ipv6: fix race condition between ipv6_get_ifaddr and ipv6_del_addr

Although ipv6_get_ifaddr walks inet6_addr_lst under the RCU lock, it
still means hlist_for_each_entry_rcu can return an item that got removed
from the list. The memory itself of such item is not freed thanks to RCU
but nothing guarantees the actual content of the memory is sane.

In particular, the reference count can be zero. This can happen if
ipv6_del_addr is called in parallel. ipv6_del_addr removes the entry
from inet6_addr_lst (hlist_del_init_rcu(&ifp->addr_lst)) and drops all
references (__in6_ifa_put(ifp) + in6_ifa_put(ifp)). With bad enough
timing, this can happen:

1. In ipv6_get_ifaddr, hlist_for_each_entry_rcu returns an entry.

2. Then, the whole ipv6_del_addr is executed for the given entry. The
reference count drops to zero and kfree_rcu is scheduled.

3. ipv6_get_ifaddr continues and tries to increments the reference count
(in6_ifa_hold).

4. The rcu is unlocked and the entry is freed.

5. The freed entry is returned.

Prevent increasing of the reference count in such case. The name
in6_ifa_hold_safe is chosen to mimic the existing fib6_info_hold_safe.

[ 41.506330] refcount_t: addition on 0; use-after-free.
[ 41.506760] WARNING: CPU: 0 PID: 595 at lib/refcount.c:25 refcount_warn_saturate+0xa5/0x130
[ 41.507413] Modules linked in: veth bridge stp llc
[ 41.507821] CPU: 0 PID: 595 Comm: python3 Not tainted 6.9.0-rc2.main-00208-g49563be82afa #14
[ 41.508479] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
[ 41.509163] RIP: 0010:refcount_warn_saturate+0xa5/0x130
[ 41.509586] Code: ad ff 90 0f 0b 90 90 c3 cc cc cc cc 80 3d c0 30 ad 01 00 75 a0 c6 05 b7 30 ad 01 01 90 48 c7 c7 38 cc 7a 8c e8 cc 18 ad ff 90 <0f> 0b 90 90 c3 cc cc cc cc 80 3d 98 30 ad 01 00 0f 85 75 ff ff ff
[ 41.510956] RSP: 0018:ffffbda3c026baf0 EFLAGS: 00010282
[ 41.511368] RAX: 0000000000000000 RBX: ffff9e9c46914800 RCX: 0000000000000000
[ 41.511910] RDX: ffff9e9c7ec29c00 RSI: ffff9e9c7ec1c900 RDI: ffff9e9c7ec1c900
[ 41.512445] RBP: ffff9e9c43660c9c R08: 0000000000009ffb R09: 00000000ffffdfff
[ 41.512998] R10: 00000000ffffdfff R11: ffffffff8ca58a40 R12: ffff9e9c4339a000
[ 41.513534] R13: 0000000000000001 R14: ffff9e9c438a0000 R15: ffffbda3c026bb48
[ 41.514086] FS: 00007fbc4cda1740(0000) GS:ffff9e9c7ec00000(0000) knlGS:0000000000000000
[ 41.514726] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 41.515176] CR2: 000056233b337d88 CR3: 000000000376e006 CR4: 0000000000370ef0
[ 41.515713] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 41.516252] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 41.516799] Call Trace:
[ 41.517037] <TASK>
[ 41.517249] ? __warn+0x7b/0x120
[ 41.517535] ? refcount_warn_saturate+0xa5/0x130
[ 41.517923] ? report_bug+0x164/0x190
[ 41.518240] ? handle_bug+0x3d/0x70
[ 41.518541] ? exc_invalid_op+0x17/0x70
[ 41.520972] ? asm_exc_invalid_op+0x1a/0x20
[ 41.521325] ? refcount_warn_saturate+0xa5/0x130
[ 41.521708] ipv6_get_ifaddr+0xda/0xe0
[ 41.522035] inet6_rtm_getaddr+0x342/0x3f0
[ 41.522376] ? __pfx_inet6_rtm_getaddr+0x10/0x10
[ 41.522758] rtnetlink_rcv_msg+0x334/0x3d0
[ 41.523102] ? netlink_unicast+0x30f/0x390
[ 41.523445] ? __pfx_rtnetlink_rcv_msg+0x10/0x10
[ 41.523832] netlink_rcv_skb+0x53/0x100
[ 41.524157] netlink_unicast+0x23b/0x390
[ 41.524484] netlink_sendmsg+0x1f2/0x440
[ 41.524826] __sys_sendto+0x1d8/0x1f0
[ 41.525145] __x64_sys_sendto+0x1f/0x30
[ 41.525467] do_syscall_64+0xa5/0x1b0
[ 41.525794] entry_SYSCALL_64_after_hwframe+0x72/0x7a
[ 41.526213] RIP: 0033:0x7fbc4cfcea9a
[ 41.526528] Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb b8 0f 1f 00 f3 0f 1e fa 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 15 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 7e c3 0f 1f 44 00 00 41 54 48 83 ec 30 44 89
[ 41.527942] RSP: 002b:00007ffcf54012a8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
[ 41.528593] RAX: ffffffffffffffda RBX: 00007ffcf5401368 RCX: 00007fbc4cfcea9a
[ 41.529173] RDX: 000000000000002c RSI: 00007fbc4b9d9bd0 RDI: 0000000000000005
[ 41.529786] RBP: 00007fbc4bafb040 R08: 00007ffcf54013e0 R09: 000000000000000c
[ 41.530375] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
[ 41.530977] R13: ffffffffc4653600 R14: 0000000000000001 R15: 00007fbc4ca85d1b
[ 41.531573] </TASK>

Fixes: 5c578aedcb21d ("IPv6: convert addrconf hash list to RCU")
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Link: https://lore.kernel.org/r/8ab821e36073a4a406c50ec83c9e8dc586c539e4.1712585809.git.jbenc@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6: Fix address dump when IPv6 is disabled on an interface

Cited commit started returning an error when user space requests to dump
the interface's IPv6 addresses and IPv6 is disabled on the interface.
Restore the previous behavior and do not return an error.

Before cited commit:

# ip address show dev dummy1
2: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
link/ether 1a:52:02:5a:c2:6e brd ff:ff:ff:ff:ff:ff
inet6 fe80::1852:2ff:fe5a:c26e/64 scope link proto kernel_ll
valid_lft forever preferred_lft forever
# ip link set dev dummy1 mtu 1000
# ip address show dev dummy1
2: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1000 qdisc noqueue state UNKNOWN group default qlen 1000
link/ether 1a:52:02:5a:c2:6e brd ff:ff:ff:ff:ff:ff

After cited commit:

# ip address show dev dummy1
2: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
link/ether 1e:9b:94:00:ac:e8 brd ff:ff:ff:ff:ff:ff
inet6 fe80::1c9b:94ff:fe00:ace8/64 scope link proto kernel_ll
valid_lft forever preferred_lft forever
# ip link set dev dummy1 mtu 1000
# ip address show dev dummy1
RTNETLINK answers: No such device
Dump terminated

With this patch:

# ip address show dev dummy1
2: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
link/ether 42:35:fc:53:66:cf brd ff:ff:ff:ff:ff:ff
inet6 fe80::4035:fcff:fe53:66cf/64 scope link proto kernel_ll
valid_lft forever preferred_lft forever
# ip link set dev dummy1 mtu 1000
# ip address show dev dummy1
2: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1000 qdisc noqueue state UNKNOWN group default qlen 1000
link/ether 42:35:fc:53:66:cf brd ff:ff:ff:ff:ff:ff

Fixes: 9cc4cc329d30 ("ipv6: use xa_array iterator to implement inet6_dump_addr()")
Reported-by: Gal Pressman <gal@nvidia.com>
Closes: https://lore.kernel.org/netdev/7e261328-42eb-411d-b1b4-ad884eeaae4d@linux.dev/
Tested-by: Gal Pressman <gal@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240321173042.2151756-1-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6: remove RTNL protection from inet6_dump_addr()

We can now remove RTNL acquisition while running
inet6_dump_addr(), inet6_dump_ifmcaddr()
and inet6_dump_ifacaddr().

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: use xa_array iterator to implement inet6_dump_addr()

inet6_dump_addr() can use the new xa_array iterator
for better scalability.

Make it ready for RCU-only protection.
RTNL use is removed in the following patch.

Also properly return 0 at the end of a dump to avoid
and extra recvmsg() to get NLMSG_DONE.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: make in6_dump_addrs() lockless

in6_dump_addrs() is called with RCU protection.

There is no need holding idev->lock to iterate through unicast addresses.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: make inet6_fill_ifaddr() lockless

Make inet6_fill_ifaddr() lockless, and add approriate annotations
on ifa->tstamp, ifa->valid_lft, ifa->preferred_lft, ifa->ifa_proto
and ifa->rt_priority.

Also constify 2nd argument of inet6_fill_ifaddr(), inet6_fill_ifmcaddr()
and inet6_fill_ifacaddr().

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

netlink: let core handle error cases in dump operations

After commit b5a899154aa9 ("netlink: handle EMSGSIZE errors
in the core"), we can remove some code that was not 100 % correct
anyway.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240306102426.245689-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6: use xa_array iterator to implement inet6_netconf_dump_devconf()

1) inet6_netconf_dump_devconf() can run under RCU protection
instead of RTNL.

2) properly return 0 at the end of a dump, avoiding an
an extra recvmsg() system call.

3) Do not use inet6_base_seq() anymore, for_each_netdev_dump()
has nice properties. Restarting a GETDEVCONF dump if a device has
been added/removed or if net->ipv6.dev_addr_genid has changed is moot.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6/addrconf: annotate data-races around devconf fields (II)

Final (?) round of this series.

Annotate lockless reads on following devconf fields,
because they be changed concurrently from /proc/net/ipv6/conf.

- accept_dad
- optimistic_dad
- use_optimistic
- use_oif_addrs_only
- ra_honor_pio_life
- keep_addr_on_down
- ndisc_notify
- ndisc_evict_nocarrier
- suppress_frag_ndisc
- addr_gen_mode
- seg6_enabled
- ioam6_enabled
- ioam6_id
- ioam6_id_wide
- drop_unicast_in_l2_multicast
- mldv[12]_unsolicited_report_interval
- force_mld_version
- force_tllao
- accept_untracked_na
- drop_unsolicited_na
- accept_source_route

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6/addrconf: annotate data-races around devconf fields (I)

Annotate lockless reads and writes on following devconf fields:

- regen_min_advance
- regen_max_retry
- dad_transmits
- use_tempaddr
- max_addresses
- max_desync_factor
- temp_valid_lft
- rtr_solicits
- rtr_solicit_max_interval
- rtr_solicit_interval
- rtr_solicit_delay
- enhanced_dad
- accept_redirects

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: addrconf_disable_policy() optimization

Writing over /proc/sys/net/ipv6/conf/default/disable_policy
does not need to hold RTNL.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: annotate data-races around devconf->disable_policy

idev->cnf.disable_policy and net->ipv6.devconf_all->disable_policy
can be read locklessly. Add appropriate annotations on reads
and writes.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: annotate data-races around devconf->proxy_ndp

devconf->proxy_ndp can be read and written locklessly,
add appropriate annotations.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: annotate data-races around idev->cnf.ignore_routes_with_linkdown

idev->cnf.ignore_routes_with_linkdown can be used without any locks,
add appropriate annotations.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: annotate data-races around cnf.forwarding

idev->cnf.forwarding and net->ipv6.devconf_all->forwarding
might be read locklessly, add appropriate READ_ONCE()
and WRITE_ONCE() annotations.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: annotate data-races around cnf.mtu6

idev->cnf.mtu6 might be read locklessly, add appropriate READ_ONCE()
and WRITE_ONCE() annotations.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: addrconf_disable_ipv6() optimization

Writing over /proc/sys/net/ipv6/conf/default/disable_ipv6
does not need to hold RTNL.

v3: remove a wrong change (Jakub Kicinski feedback)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: annotate data-races around cnf.disable_ipv6

disable_ipv6 is read locklessly, add appropriate READ_ONCE()
and WRITE_ONCE() annotations.

v2: do not preload net before rtnl_trylock() in
addrconf_disable_ipv6() (Jiri)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

inet6: expand rcu_read_lock() scope in inet6_dump_addr()

I missed that inet6_dump_addr() is calling in6_dump_addrs()
from two points.

First one under RTNL protection, and second one under rcu_read_lock().

Since we want to remove RTNL use from inet6_dump_addr() very soon,
no longer assume in6_dump_addrs() is protected by RTNL (even
if this is still the case).

Use rcu_read_lock() earlier to fix this lockdep splat:

WARNING: suspicious RCU usage
6.8.0-rc5-syzkaller-01618-gf8cbf6bde4c8 #0 Not tainted

net/ipv6/addrconf.c:5317 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
3 locks held by syz-executor.2/8834:
#0: ffff88802f554678 (nlk_cb_mutex-ROUTE){+.+.}-{3:3}, at: __netlink_dump_start+0x119/0x780 net/netlink/af_netlink.c:2338
#1: ffffffff8f377a88 (rtnl_mutex){+.+.}-{3:3}, at: netlink_dump+0x676/0xda0 net/netlink/af_netlink.c:2265
#2: ffff88807e5f0580 (&ndev->lock){++--}-{2:2}, at: in6_dump_addrs+0xb8/0x1de0 net/ipv6/addrconf.c:5279

stack backtrace:
CPU: 1 PID: 8834 Comm: syz-executor.2 Not tainted 6.8.0-rc5-syzkaller-01618-gf8cbf6bde4c8 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106
lockdep_rcu_suspicious+0x220/0x340 kernel/locking/lockdep.c:6712
in6_dump_addrs+0x1b47/0x1de0 net/ipv6/addrconf.c:5317
inet6_dump_addr+0x1597/0x1690 net/ipv6/addrconf.c:5428
netlink_dump+0x6a6/0xda0 net/netlink/af_netlink.c:2266
__netlink_dump_start+0x59d/0x780 net/netlink/af_netlink.c:2374
netlink_dump_start include/linux/netlink.h:340 [inline]
rtnetlink_rcv_msg+0xcf7/0x10d0 net/core/rtnetlink.c:6555
netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2547
netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1361
netlink_sendmsg+0x8e0/0xcb0 net/netlink/af_netlink.c:1902
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:745
____sys_sendmsg+0x525/0x7d0 net/socket.c:2584
___sys_sendmsg net/socket.c:2638 [inline]
__sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667

Fixes: c3718936ec47 ("ipv6: anycast: complete RCU handling of struct ifacaddr6")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20240227222259.4081489-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6: anycast: complete RCU handling of struct ifacaddr6

struct ifacaddr6 are already freed after RCU grace period.

Add __rcu qualifier to aca_next pointer, and idev->ac_list

Add relevant rcu_assign_pointer() and dereference accessors.

ipv6_chk_acast_dev() no longer needs to acquire idev->lock.

/proc/net/anycast6 is now purely RCU protected, it no
longer acquires idev->lock.

Similarly in6_dump_addrs() can use RCU protection to iterate
through anycast addresses. It was relying on a mixture of RCU
and RTNL but next patches will get rid of RTNL there.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20240223201054.220534-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6: switch inet6_dump_ifinfo() to RCU protection

No longer hold RTNL while calling inet6_dump_ifinfo()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: use xarray iterator to implement inet6_dump_ifinfo()

Prepare inet6_dump_ifinfo() to run with RCU protection
instead of RTNL and use for_each_netdev_dump() interface.

Also properly return 0 at the end of a dump, avoiding
an extra recvmsg() system call and RTNL acquisition.

Note that RTNL-less dumps need core changes, coming later
in the series.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: prepare inet6_fill_ifinfo() for RCU protection

We want to use RCU protection instead of RTNL
for inet6_fill_ifinfo().

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: prepare inet6_fill_ifla6_attrs() for RCU

We want to no longer hold RTNL while calling inet6_fill_ifla6_attrs()
in the future. Add needed READ_ONCE()/WRITE_ONCE() annotations.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipv6/addrconf: clamp preferred_lft to the minimum required

If the preferred lifetime was less than the minimum required lifetime,
ipv6_create_tempaddr would error out without creating any new address.
On my machine and network, this error happened immediately with the
preferred lifetime set to 5 seconds or less, after a few minutes with
the preferred lifetime set to 6 seconds, and not at all with the
preferred lifetime set to 7 seconds. During my investigation, I found a
Stack Exchange post from another person who seems to have had the same
problem: They stopped getting new addresses if they lowered the
preferred lifetime below 3 seconds, and they didn't really know why.

The preferred lifetime is a preference, not a hard requirement. The
kernel does not strictly forbid new connections on a deprecated address,
nor does it guarantee that the address will be disposed of the instant
its total valid lifetime expires. So rather than disable IPv6 privacy
extensions altogether if the minimum required lifetime swells above the
preferred lifetime, it is more in keeping with the user's intent to
increase the temporary address's lifetime to the minimum necessary for
the current network conditions.

With these fixes, setting the preferred lifetime to 5 or 6 seconds "just
works" because the extra fraction of a second is practically
unnoticeable. It's even possible to reduce the time before deprecation
to 1 or 2 seconds by setting /proc/sys/net/ipv6/conf/*/regen_min_advance
and /proc/sys/net/ipv6/conf/*/dad_transmits to 0. I realize that that is
a pretty niche use case, but I know at least one person who would gladly
sacrifice performance and convenience to be sure that they are getting
the maximum possible level of privacy.

Link: https://serverfault.com/a/1031168/310447
Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

net: ipv6/addrconf: introduce a regen_min_advance sysctl

In RFC 8981, REGEN_ADVANCE cannot be less than 2 seconds, and the RFC
does not permit the creation of temporary addresses with lifetimes
shorter than that:

> When processing a Router Advertisement with a
> Prefix Information option carrying a prefix for the purposes of
> address autoconfiguration (i.e., the A bit is set), the host MUST
> perform the following steps:

> 5. A temporary address is created only if this calculated preferred
> lifetime is greater than REGEN_ADVANCE time units.

However, some users want to change their IPv6 address as frequently as
possible regardless of the RFC's arbitrary minimum lifetime. For the
benefit of those users, add a regen_min_advance sysctl parameter that
can be set to below or above 2 seconds.

Link: https://datatracker.ietf.org/doc/html/rfc8981
Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

net: ipv6/addrconf: ensure that regen_advance is at least 2 seconds

RFC 8981 defines REGEN_ADVANCE as follows:

REGEN_ADVANCE = 2 + (TEMP_IDGEN_RETRIES * DupAddrDetectTransmits * RetransTimer / 1000)

Thus, allowing it to be less than 2 seconds is technically a protocol
violation.

Link: https://datatracker.ietf.org/doc/html/rfc8981#name-defined-protocol-parameters
Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

net-sysfs: convert dev->operstate reads to lockless ones

operstate_show() can omit dev_base_lock acquisition only
to read dev->operstate.

Annotate accesses to dev->operstate.

Writers still acquire dev_base_lock for mutual exclusion.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: set expires in modify_prefix_route() if RTF_EXPIRES is set.

Make the decision to set or clean the expires of a route based on the
RTF_EXPIRES flag, rather than the value of the "expires" argument.

This patch doesn't make difference logically, but make inet6_addr_modify()
and modify_prefix_route() consistent.

The function inet6_addr_modify() is the only caller of
modify_prefix_route(), and it passes the RTF_EXPIRES flag and an expiration
value. The RTF_EXPIRES flag is turned on or off based on the value of
valid_lft. The RTF_EXPIRES flag is turned on if valid_lft is a finite value
(not infinite, not 0xffffffff). Even if valid_lft is 0, the RTF_EXPIRES
flag remains on. The expiration value being passed is equal to the
valid_lft value if the flag is on. However, if the valid_lft value is
infinite, the expiration value becomes 0 and the RTF_EXPIRES flag is turned
off. Despite this, modify_prefix_route() decides to set the expiration
value if the received expiration value is not zero. This mixing of infinite
and zero cases creates an inconsistency.

Reviewed-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Remove expired routes with a separated list of routes.

FIB6 GC walks trees of fib6_tables to remove expired routes. Walking a tree
can be expensive if the number of routes in a table is big, even if most of
them are permanent. Checking routes in a separated list of routes having
expiration will avoid this potential issue.

Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: make addrconf_wq single threaded

Both addrconf_verify_work() and addrconf_dad_work() acquire rtnl,
there is no point trying to have one thread per cpu.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240201173031.3654257-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6: fix potential "struct net" leak in inet6_rtm_getaddr()

It seems that if userspace provides a correct IFA_TARGET_NETNSID value
but no IFA_ADDRESS and IFA_LOCAL attributes, inet6_rtm_getaddr()
returns -EINVAL with an elevated "struct net" refcount.

Fixes: 6ecf4c37eb3e ("ipv6: enable IFA_TARGET_NETNSID for RTM_GETADDR")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Ahern <dsahern@kernel.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: properly combine dev_base_seq and ipv6.dev_addr_genid

net->dev_base_seq and ipv6.dev_addr_genid are monotonically increasing.

If we XOR their values, we could miss to detect if both values
were changed with the same amount.

Fixes: 63998ac24f83 ("ipv6: provide addr and netconf dump consistency info")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Revert "net: ipv6/addrconf: clamp preferred_lft to the minimum required"

The commit had a bug and might not have been the right approach anyway.

Fixes: 629df6701c8a ("net: ipv6/addrconf: clamp preferred_lft to the minimum required")
Fixes: ec575f885e3e ("Documentation: networking: explain what happens if temp_prefered_lft is too small or too large")
Reported-by: Dan Moulding <dan@danm.net>
Closes: https://lore.kernel.org/netdev/20231221231115.12402-1-dan@danm.net/
Link: https://lore.kernel.org/netdev/CAMMLpeTdYhd=7hhPi2Y7pwdPCgnnW5JYh-bu3hSc7im39uxnEA@mail.gmail.com/
Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20231230043252.10530-1-alexhenrie24@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipv6: support reporting otherwise unknown prefix flags in RTM_NEWPREFIX

Lorenzo points out that we effectively clear all unknown
flags from PIO when copying them to userspace in the netlink
RTM_NEWPREFIX notification.

We could fix this one at a time as new flags are defined,
or in one fell swoop - I choose the latter.

We could either define 6 new reserved flags (reserved1..6) and handle
them individually (and rename them as new flags are defined), or we
could simply copy the entire unmodified byte over - I choose the latter.

This unfortunately requires some anonymous union/struct magic,
so we add a static assert on the struct size for a little extra safety.

Cc: David Ahern <dsahern@kernel.org>
Cc: Lorenzo Colitti <lorenzo@google.com>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipv6/addrconf: clamp preferred_lft to the minimum required

If the preferred lifetime was less than the minimum required lifetime,
ipv6_create_tempaddr would error out without creating any new address.
On my machine and network, this error happened immediately with the
preferred lifetime set to 1 second, after a few minutes with the
preferred lifetime set to 4 seconds, and not at all with the preferred
lifetime set to 5 seconds. During my investigation, I found a Stack
Exchange post from another person who seems to have had the same
problem: They stopped getting new addresses if they lowered the
preferred lifetime below 3 seconds, and they didn't really know why.

The preferred lifetime is a preference, not a hard requirement. The
kernel does not strictly forbid new connections on a deprecated address,
nor does it guarantee that the address will be disposed of the instant
its total valid lifetime expires. So rather than disable IPv6 privacy
extensions altogether if the minimum required lifetime swells above the
preferred lifetime, it is more in keeping with the user's intent to
increase the temporary address's lifetime to the minimum necessary for
the current network conditions.

With these fixes, setting the preferred lifetime to 3 or 4 seconds "just
works" because the extra fraction of a second is practically
unnoticeable. It's even possible to reduce the time before deprecation
to 1 or 2 seconds by also disabling duplicate address detection (setting
/proc/sys/net/ipv6/conf/*/dad_transmits to 0). I realize that that is a
pretty niche use case, but I know at least one person who would gladly
sacrifice performance and convenience to be sure that they are getting
the maximum possible level of privacy.

Link: https://serverfault.com/a/1031168/310447
Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20231024212312.299370-3-alexhenrie24@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipv6/addrconf: clamp preferred_lft to the maximum allowed

Without this patch, there is nothing to stop the preferred lifetime of a
temporary address from being greater than its valid lifetime. If that
was the case, the valid lifetime was effectively ignored.

Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20231024212312.299370-2-alexhenrie24@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: add sysctl to disable rfc4862 5.5.3e lifetime handling

This change adds a sysctl to opt-out of RFC4862 section 5.5.3e's valid
lifetime derivation mechanism.

RFC4862 section 5.5.3e prescribes that the valid lifetime in a Router
Advertisement PIO shall be ignored if it less than 2 hours and to reset
the lifetime of the corresponding address to 2 hours. An in-progress
6man draft (see draft-ietf-6man-slaac-renum-07 section 4.2) is currently
looking to remove this mechanism. While this draft has not been moving
particularly quickly for other reasons, there is widespread consensus on
section 4.2 which updates RFC4862 section 5.5.3e.

Cc: Maciej Żenczykowski <maze@google.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Cc: Jen Linkova <furry@google.com>
Signed-off-by: Patrick Rohr <prohr@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20230925214711.959704-1-prohr@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipv6/addrconf: avoid integer underflow in ipv6_create_tempaddr

The existing code incorrectly casted a negative value (the result of a
subtraction) to an unsigned value without checking. For example, if
/proc/sys/net/ipv6/conf/*/temp_prefered_lft was set to 1, the preferred
lifetime would jump to 4 billion seconds. On my machine and network the
shortest lifetime that avoided underflow was 3 seconds.

Fixes: 76506a986dc3 ("IPv6: fix DESYNC_FACTOR")
Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: release reference to inet6_dev pointer

addrconf_prefix_rcv returned early without releasing the inet6_dev
pointer when the PIO lifetime is less than accept_ra_min_lft.

Fixes: 5027d54a9c30 ("net: change accept_ra_min_rtr_lft to affect all RA lifetimes")
Cc: Maciej Żenczykowski <maze@google.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Cc: David Ahern <dsahern@kernel.org>
Cc: Simon Horman <horms@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Patrick Rohr <prohr@google.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

networking: Update to register_net_sysctl_sz

Move from register_net_sysctl to register_net_sysctl_sz for all the
networking related files. Do this while making sure to mirror the NULL
assignments with a table_size of zero for the unprivileged users.

We need to move to the new function in preparation for when we change
SIZE_MAX to ARRAY_SIZE() in the register_net_sysctl macro. Failing to do
so would erroneously allow ARRAY_SIZE() to be called on a pointer. We
hold off the SIZE_MAX to ARRAY_SIZE change until we have migrated all
the relevant net sysctl registering functions to register_net_sysctl_sz
in subsequent commits.

An additional size function was added to the following files in order to
calculate the size of an array that is defined in another file:
include/net/ipv6.h
net/ipv6/icmp.c
net/ipv6/route.c
net/ipv6/sysctl_net_ipv6.c

Signed-off-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

net: change accept_ra_min_rtr_lft to affect all RA lifetimes

accept_ra_min_rtr_lft only considered the lifetime of the default route
and discarded entire RAs accordingly.

This change renames accept_ra_min_rtr_lft to accept_ra_min_lft, and
applies the value to individual RA sections; in particular, router
lifetime, PIO preferred lifetime, and RIO lifetime. If any of those
lifetimes are lower than the configured value, the specific RA section
is ignored.

In order for the sysctl to be useful to Android, it should really apply
to all lifetimes in the RA, since that is what determines the minimum
frequency at which RAs must be processed by the kernel. Android uses
hardware offloads to drop RAs for a fraction of the minimum of all
lifetimes present in the RA (some networks have very frequent RAs (5s)
with high lifetimes (2h)). Despite this, we have encountered networks
that set the router lifetime to 30s which results in very frequent CPU
wakeups. Instead of disabling IPv6 (and dropping IPv6 ethertype in the
WiFi firmware) entirely on such networks, it seems better to ignore the
misconfigured routers while still processing RAs from other IPv6 routers
on the same network (i.e. to support IoT applications).

The previous implementation dropped the entire RA based on router
lifetime. This turned out to be hard to expand to the other lifetimes
present in the RA in a consistent manner; dropping the entire RA based
on RIO/PIO lifetimes would essentially require parsing the whole thing
twice.

Fixes: 1671bcfd76fd ("net: add sysctl accept_ra_min_rtr_lft")
Cc: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: Patrick Rohr <prohr@google.com>
Reviewed-by: Maciej Żenczykowski <maze@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20230726230701.919212-1-prohr@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

IPv6: add extack info for IPv6 address add/delete

Add extack info for IPv6 address add/delete, which would be useful for
users to understand the problem without having to read kernel code.

Suggested-by: Beniamino Galvani <bgalvani@redhat.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: add sysctl accept_ra_min_rtr_lft

This change adds a new sysctl accept_ra_min_rtr_lft to specify the
minimum acceptable router lifetime in an RA. If the received RA router
lifetime is less than the configured value (and not 0), the RA is
ignored.
This is useful for mobile devices, whose battery life can be impacted
by networks that configure RAs with a short lifetime. On such networks,
the device should never gain IPv6 provisioning and should attempt to
drop RAs via hardware offload, if available.

Signed-off-by: Patrick Rohr <prohr@google.com>
Cc: Maciej Żenczykowski <maze@google.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6 addrconf: fix bug where deleting a mngtmpaddr can create a new temporary address

currently on 6.4 net/main:

# ip link add dummy1 type dummy
# echo 1 > /proc/sys/net/ipv6/conf/dummy1/use_tempaddr
# ip link set dummy1 up
# ip -6 addr add 2000::1/64 mngtmpaddr dev dummy1
# ip -6 addr show dev dummy1

11: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
inet6 2000::44f3:581c:8ca:3983/64 scope global temporary dynamic
valid_lft 604800sec preferred_lft 86172sec
inet6 2000::1/64 scope global mngtmpaddr
valid_lft forever preferred_lft forever
inet6 fe80::e8a8:a6ff:fed5:56d4/64 scope link
valid_lft forever preferred_lft forever

# ip -6 addr del 2000::44f3:581c:8ca:3983/64 dev dummy1

(can wait a few seconds if you want to, the above delete isn't [directly] the problem)

# ip -6 addr show dev dummy1

11: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
inet6 2000::1/64 scope global mngtmpaddr
valid_lft forever preferred_lft forever
inet6 fe80::e8a8:a6ff:fed5:56d4/64 scope link
valid_lft forever preferred_lft forever

# ip -6 addr del 2000::1/64 mngtmpaddr dev dummy1
# ip -6 addr show dev dummy1

11: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
inet6 2000::81c9:56b7:f51a:b98f/64 scope global temporary dynamic
valid_lft 604797sec preferred_lft 86169sec
inet6 fe80::e8a8:a6ff:fed5:56d4/64 scope link
valid_lft forever preferred_lft forever

This patch prevents this new 'global temporary dynamic' address from being
created by the deletion of the related (same subnet prefix) 'mngtmpaddr'
(which is triggered by there already being no temporary addresses).

Cc: Jiri Pirko <jiri@resnulli.us>
Fixes: 53bd67491537 ("ipv6 addrconf: introduce IFA_F_MANAGETEMPADDR to tell kernel to manage temporary addresses")
Reported-by: Xiao Ma <xiaom@google.com>
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20230720160022.1887942-1-maze@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6/addrconf: fix a potential refcount underflow for idev

Now in addrconf_mod_rs_timer(), reference idev depends on whether
rs_timer is not pending. Then modify rs_timer timeout.

There is a time gap in [1], during which if the pending rs_timer
becomes not pending. It will miss to hold idev, but the rs_timer
is activated. Thus rs_timer callback function addrconf_rs_timer()
will be executed and put idev later without holding idev. A refcount
underflow issue for idev can be caused by this.

if (!timer_pending(&idev->rs_timer))
in6_dev_hold(idev);
<--------------[1]
mod_timer(&idev->rs_timer, jiffies + when);

To fix the issue, hold idev if mod_timer() return 0.

Fixes: b7b1bfce0bb6 ("ipv6: split duplicate address detection and router solicitation timer")
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: lower "link become ready"'s level message

This following message is printed in the console each time a network
device configured with an IPv6 addresses is ready to be used:

ADDRCONF(NETDEV_CHANGE): <iface>: link becomes ready

When netns are being extensively used -- e.g. by re-creating netns' with
veth to discuss with each others for testing purposes like mptcp_join.sh
selftest does -- it generates a lot of messages like that: more than 700
when executing mptcp_join.sh with the latest version.

It looks like this message is not that helpful after all: maybe it can
be used as a sign to know if there is something wrong, e.g. if a device
is being regularly reconfigured by accident? But even then, there are
better ways to monitor and diagnose such issues.

When looking at commit 3c21edbd1137 ("[IPV6]: Defer IPv6 device
initialization until the link becomes ready.") which introduces this new
message, it seems it had been added to verify that the new feature was
working as expected. It could have then used a lower level than "info"
from the beginning but it was fine like that back then: 17 years ago.

It seems then OK today to simply lower its level, similar to commit
7c62b8dd5ca8 ("net/ipv6: lower the level of "link is not ready" messages")
and as suggested by Mat [1], Stephen and David [2].

Link: https://lore.kernel.org/mptcp/614e76ac-184e-c553-af72-084f792e60b0@kernel.org/T/ [1]
Link: https://lore.kernel.org/netdev/68035bad-b53e-91cb-0e4a-007f27d62b05@tessares.net/T/ [2]
Suggested-by: Mat Martineau <martineau@kernel.org>
Suggested-by: Stephen Hemminger <stephen@networkplumber.org>
Suggested-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: prevent router_solicitations for team port

The issue fixed for bonding in commit c2edacf80e15 ("bonding / ipv6: no
addrconf for slaves separately from master") also exists in team driver.
However, we can't just disable ipv6 addrconf for team ports, as 'teamd'
will need it when nsns_ping watch is used in the user space.

Instead of preventing ipv6 addrconf, this patch only prevents RS packets
for team ports, as it did in commit b52e1cce31ca ("ipv6: Don't send rs
packets to the interface of ARPHRD_TUNNEL").

Note that we do not prevent DAD packets, to avoid the changes getting
intricate / hacky. Also, usually sysctl dad_transmits is set to 1 and
only 1 DAD packet will be sent, and by now no libteam user complains
about DAD packets on team ports, unlike RS packets.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

neighbour: switch to standard rcu, instead of rcu_bh

rcu_bh is no longer a win, especially for objects freed
with standard call_rcu().

Switch neighbour code to no longer disable BH when not necessary.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ip/ip6_gre: Fix non-point-to-point tunnel not generating IPv6 link local address

We recently found that our non-point-to-point tunnels were not
generating any IPv6 link local address and instead generating an
IPv6 compat address, breaking IPv6 communication on the tunnel.

Previously, addrconf_gre_config always would call addrconf_addr_gen
and generate a EUI64 link local address for the tunnel.
Then commit e5dd729460ca changed the code path so that add_v4_addrs
is called but this only generates a compat IPv6 address for
non-point-to-point tunnels.

I assume the compat address is specifically for SIT tunnels so
have kept that only for SIT - GRE tunnels now always generate link
local addresses.

Fixes: e5dd729460ca ("ip/ip6_gre: use the same logic as SIT interfaces when computing v6LL address")
Signed-off-by: Thomas Winter <Thomas.Winter@alliedtelesis.co.nz>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ip/ip6_gre: Fix changing addr gen mode not generating IPv6 link local address

For our point-to-point GRE tunnels, they have IN6_ADDR_GEN_MODE_NONE
when they are created then we set IN6_ADDR_GEN_MODE_EUI64 when they
come up to generate the IPv6 link local address for the interface.
Recently we found that they were no longer generating IPv6 addresses.
This issue would also have affected SIT tunnels.

Commit e5dd729460ca changed the code path so that GRE tunnels
generate an IPv6 address based on the tunnel source address.
It also changed the code path so GRE tunnels don't call addrconf_addr_gen
in addrconf_dev_config which is called by addrconf_sysctl_addr_gen_mode
when the IN6_ADDR_GEN_MODE is changed.

This patch aims to fix this issue by moving the code in addrconf_notify
which calls the addr gen for GRE and SIT into a separate function
and calling it in the places that expect the IPv6 address to be
generated.

The previous addrconf_dev_config is renamed to addrconf_eth_config
since it only expected eth type interfaces and follows the
addrconf_gre/sit_config format.

A part of this changes means that the loopback address will be
attempted to be configured when changing addr_gen_mode for lo.
This should not be a problem because the address should exist anyway
and if does already exist then no error is produced.

Fixes: e5dd729460ca ("ip/ip6_gre: use the same logic as SIT interfaces when computing v6LL address")
Signed-off-by: Thomas Winter <Thomas.Winter@alliedtelesis.co.nz>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: add IFF_NO_ADDRCONF and use it in bonding to prevent ipv6 addrconf

Currently, in bonding it reused the IFF_SLAVE flag and checked it
in ipv6 addrconf to prevent ipv6 addrconf.

However, it is not a proper flag to use for no ipv6 addrconf, for
bonding it has to move IFF_SLAVE flag setting ahead of dev_open()
in bond_enslave(). Also, IFF_MASTER/SLAVE are historical flags
used in bonding and eql, as Jiri mentioned, the new devices like
Team, Failover do not use this flag.

So as Jiri suggested, this patch adds IFF_NO_ADDRCONF in priv_flags
of the device to indicate no ipv6 addconf, and uses it in bonding
and moves IFF_SLAVE flag setting back to its original place.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

treewide: use get_random_u32_inclusive() when possible

These cases were done with this Coccinelle:

@@
expression H;
expression L;
@@
- (get_random_u32_below(H) + L)
+ get_random_u32_inclusive(L, H + L - 1)

@@
expression H;
expression L;
expression E;
@@
get_random_u32_inclusive(L,
H
- + E
- - E
)

@@
expression H;
expression L;
expression E;
@@
get_random_u32_inclusive(L,
H
- - E
- + E
)

@@
expression H;
expression L;
expression E;
expression F;
@@
get_random_u32_inclusive(L,
H
- - E
+ F
- + E
)

@@
expression H;
expression L;
expression E;
expression F;
@@
get_random_u32_inclusive(L,
H
- + E
+ F
- - E
)

And then subsequently cleaned up by hand, with several automatic cases
rejected if it didn't make sense contextually.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> # for infiniband
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

treewide: use get_random_u32_below() instead of deprecated function

This is a simple mechanical transformation done by:

@@
expression E;
@@
- prandom_u32_max
+ get_random_u32_below
(E)

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Reviewed-by: SeongJae Park <sj@kernel.org> # for damon
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> # for infiniband
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> # for arm
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

ip6mr: fix UAF issue in ip6mr_sk_done() when addrconf_init_net() failed

If the initialization fails in calling addrconf_init_net(), devconf_all is
the pointer that has been released. Then ip6mr_sk_done() is called to
release the net, accessing devconf->mc_forwarding directly causes invalid
pointer access.

The process is as follows:
setup_net()
ops_init()
addrconf_init_net()
all = kmemdup(...) ---> alloc "all"
...
net->ipv6.devconf_all = all;
__addrconf_sysctl_register() ---> failed
...
kfree(all); ---> ipv6.devconf_all invalid
...
ops_exit_list()
...
ip6mr_sk_done()
devconf = net->ipv6.devconf_all;
//devconf is invalid pointer
if (!devconf || !atomic_read(&devconf->mc_forwarding))

The following is the Call Trace information:
BUG: KASAN: use-after-free in ip6mr_sk_done+0x112/0x3a0
Read of size 4 at addr ffff888075508e88 by task ip/14554
Call Trace:
<TASK>
dump_stack_lvl+0x8e/0xd1
print_report+0x155/0x454
kasan_report+0xba/0x1f0
kasan_check_range+0x35/0x1b0
ip6mr_sk_done+0x112/0x3a0
rawv6_close+0x48/0x70
inet_release+0x109/0x230
inet6_release+0x4c/0x70
sock_release+0x87/0x1b0
igmp6_net_exit+0x6b/0x170
ops_exit_list+0xb0/0x170
setup_net+0x7ac/0xbd0
copy_net_ns+0x2e6/0x6b0
create_new_namespaces+0x382/0xa50
unshare_nsproxy_namespaces+0xa6/0x1c0
ksys_unshare+0x3a4/0x7e0
__x64_sys_unshare+0x2d/0x40
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7f7963322547

</TASK>
Allocated by task 14554:
kasan_save_stack+0x1e/0x40
kasan_set_track+0x21/0x30
__kasan_kmalloc+0xa1/0xb0
__kmalloc_node_track_caller+0x4a/0xb0
kmemdup+0x28/0x60
addrconf_init_net+0x1be/0x840
ops_init+0xa5/0x410
setup_net+0x5aa/0xbd0
copy_net_ns+0x2e6/0x6b0
create_new_namespaces+0x382/0xa50
unshare_nsproxy_namespaces+0xa6/0x1c0
ksys_unshare+0x3a4/0x7e0
__x64_sys_unshare+0x2d/0x40
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0

Freed by task 14554:
kasan_save_stack+0x1e/0x40
kasan_set_track+0x21/0x30
kasan_save_free_info+0x2a/0x40
____kasan_slab_free+0x155/0x1b0
slab_free_freelist_hook+0x11b/0x220
__kmem_cache_free+0xa4/0x360
addrconf_init_net+0x623/0x840
ops_init+0xa5/0x410
setup_net+0x5aa/0xbd0
copy_net_ns+0x2e6/0x6b0
create_new_namespaces+0x382/0xa50
unshare_nsproxy_namespaces+0xa6/0x1c0
ksys_unshare+0x3a4/0x7e0
__x64_sys_unshare+0x2d/0x40
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0

Fixes: 7d9b1b578d67 ("ip6mr: fix use-after-free in ip6mr_sk_done()")
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20221017080331.16878-1-shaozhengchao@huawei.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

treewide: use prandom_u32_max() when possible, part 1

Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:

@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
|
- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)

@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@

- RAND = get_random_u32();
... when != RAND
- RAND %= (E);
+ RAND = prandom_u32_max(E);

// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@

((T)get_random_u32()@p & (LITERAL))

// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@

value = None
if literal.startswith('0x'):
value = int(literal, 16)
elif literal[0] in '123456789':
value = int(literal, 10)
if value is None:
print("I don't know how to handle %s" % (literal))
cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
print("Skipping 0x%x for cleanup elsewhere" % (value))
cocci.include_match(False)
elif value & (value + 1) != 0:
print("Skipping 0x%x because it's not a power of two minus one" % (value))
cocci.include_match(False)
elif literal.startswith('0x'):
coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))

// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@

- (FUNC()@p & (LITERAL))
+ prandom_u32_max(RESULT)

@collapse_ret@
type T;
identifier VAR;
expression E;
@@

{
- T VAR;
- VAR = (E);
- return VAR;
+ return E;
}

@drop_var@
type T;
identifier VAR;
@@

{
- T VAR;
... when != VAR
}

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

bonding: add all node mcast address when slave up

When a link is enslave to bond, it need to set the interface down first.
This makes the slave remove mac multicast address 33:33:00:00:00:01(The
IPv6 multicast address ff02::1 is kept even when the interface down). When
bond set the slave up, ipv6_mc_up() was not called due to commit c2edacf80e15
("bonding / ipv6: no addrconf for slaves separately from master").

This is not an issue before we adding the lladdr target feature for bonding,
as the mac multicast address will be added back when bond interface up and
join group ff02::1.

But after adding lladdr target feature for bonding. When user set a lladdr
target, the unsolicited NA message with all-nodes multicast dest will be
dropped as the slave interface never add 33:33:00:00:00:01 back.

Fix this by calling ipv6_mc_up() to add 33:33:00:00:00:01 back when
the slave interface up.

Reported-by: LiLiang <liali@redhat.com>
Fixes: 5e1eeef69c0f ("bonding: NS target should accept link local address")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Fix data-races around sysctl_devconf_inherit_init_net.

While reading sysctl_devconf_inherit_init_net, it can be changed
concurrently. Thus, we need to add READ_ONCE() to its readers.

Fixes: 856c395cfa63 ("net: introduce a knob to control whether to inherit devconf config")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipv6: avoid accepting values greater than 2 for accept_untracked_na

The accept_untracked_na sysctl changed from a boolean to an integer
when a new knob '2' was added. This patch provides a safeguard to avoid
accepting values that are not defined in the sysctl. When setting a
value greater than 2, the user will get an 'invalid argument' warning.

Fixes: aaa5f515b16b ("net: ipv6: new accept_untracked_na option to accept na only if in-network")
Signed-off-by: Jaehee Park <jhpark1013@gmail.com>
Suggested-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Suggested-by: Roopa Prabhu <roopa@nvidia.com>
Reviewed-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20220720183632.376138-1-jhpark1013@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipv6: new accept_untracked_na option to accept na only if in-network

This patch adds a third knob, '2', which extends the
accept_untracked_na option to learn a neighbor only if the src ip is
in the same subnet as an address configured on the interface that
received the neighbor advertisement. This is similar to the arp_accept
configuration for ipv4.

Signed-off-by: Jaehee Park <jhpark1013@gmail.com>
Suggested-by: Roopa Prabhu <roopa@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6/addrconf: fix timing bug in tempaddr regen

The addrconf_verify_rtnl() function uses a big if/elseif/elseif/... block
to categorize each address by what type of attention it needs. An
about-to-expire (RFC 4941) temporary address is one such category, but the
previous elseif branch catches addresses that have already run out their
prefered_lft. This means that if addrconf_verify_rtnl() fails to run in
the necessary time window (i.e. REGEN_ADVANCE time units before the end of
the prefered_lft), the temporary address will never be regenerated, and no
temporary addresses will be available until each one's valid_lft runs out
and manage_tempaddrs() begins anew.

Fix this by moving the entire temporary address regeneration case out of
that block. That block is supposed to implement the "destructive" part of
an address's lifecycle, and regenerating a fresh temporary address is not,
semantically speaking, actually tied to any particular lifecycle stage.
The age test is also changed from `age >= prefered_lft - regen_advance`
to `age + regen_advance >= prefered_lft` instead, to ensure no underflow
occurs if the system administrator increases the regen_advance to a value
greater than the already-set prefered_lft.

Note that this does not fix the problem of addrconf_verify_rtnl() sometimes
not running in time, resulting in the race condition described in RFC 4941
section 3.4 - it only ensures that the address is regenerated. Fixing THAT
problem may require either using jiffies instead of seconds for all time
arithmetic here, or always rounding up when regen_advance is converted to
seconds.

Signed-off-by: Sam Edwards <CFSworks@gmail.com>
Link: https://lore.kernel.org/r/20220623181103.7033-1-CFSworks@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

net: rename reference+tracking helpers

Netdev reference helpers have a dev_ prefix for historic
reasons. Renaming the old helpers would be too much churn
but we can rename the tracking ones which are relatively
recent and should be the default for new code.

Rename:
dev_hold_track() -> netdev_hold()
dev_put_track() -> netdev_put()
dev_replace_track() -> netdev_ref_replace()

Link: https://lore.kernel.org/r/20220608043955.919359-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6: fix lockdep splat in in6_dump_addrs()

As reported by syzbot, we should not use rcu_dereference()
when rcu_read_lock() is not held.

WARNING: suspicious RCU usage
5.19.0-rc2-syzkaller #0 Not tainted

net/ipv6/addrconf.c:5175 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
1 lock held by syz-executor326/3617:
#0: ffffffff8d5848e8 (rtnl_mutex){+.+.}-{3:3}, at: netlink_dump+0xae/0xc20 net/netlink/af_netlink.c:2223

stack backtrace:
CPU: 0 PID: 3617 Comm: syz-executor326 Not tainted 5.19.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
in6_dump_addrs+0x12d1/0x1790 net/ipv6/addrconf.c:5175
inet6_dump_addr+0x9c1/0xb50 net/ipv6/addrconf.c:5300
netlink_dump+0x541/0xc20 net/netlink/af_netlink.c:2275
__netlink_dump_start+0x647/0x900 net/netlink/af_netlink.c:2380
netlink_dump_start include/linux/netlink.h:245 [inline]
rtnetlink_rcv_msg+0x73e/0xc90 net/core/rtnetlink.c:6046
netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2501
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x543/0x7f0 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x917/0xe10 net/netlink/af_netlink.c:1921
sock_sendmsg_nosec net/socket.c:714 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:734
____sys_sendmsg+0x6eb/0x810 net/socket.c:2492
___sys_sendmsg+0xf3/0x170 net/socket.c:2546
__sys_sendmsg net/socket.c:2575 [inline]
__do_sys_sendmsg net/socket.c:2584 [inline]
__se_sys_sendmsg net/socket.c:2582 [inline]
__x64_sys_sendmsg+0x132/0x220 net/socket.c:2582
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x46/0xb0

Fixes: 88e2ca308094 ("mld: convert ifmcaddr6 to RCU")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Taehee Yoo <ap420073@gmail.com>
Link: https://lore.kernel.org/r/20220628121248.858695-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6: take care of disable_policy when restoring routes

When routes corresponding to addresses are restored by
fixup_permanent_addr(), the dst_nopolicy parameter was not set.
The typical use case is a user that configures an address on a down
interface and then put this interface up.

Let's take care of this flag in addrconf_f6i_alloc(), so that every callers
benefit ont it.

CC: stable@kernel.org
CC: David Forster <dforster@brocade.com>
Fixes: df789fe75206 ("ipv6: Provide ipv6 version of "disable_policy" sysctl")
Reported-by: Siwar Zitouni <siwar.zitouni@6wind.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20220623120015.32640-1-nicolas.dichtel@6wind.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/ipv6: Expand and rename accept_unsolicited_na to accept_untracked_na

RFC 9131 changes default behaviour of handling RX of NA messages when the
corresponding entry is absent in the neighbour cache. The current
implementation is limited to accept just unsolicited NAs. However, the
RFC is more generic where it also accepts solicited NAs. Both types
should result in adding a STALE entry for this case.

Expand accept_untracked_na behaviour to also accept solicited NAs to
be compliant with the RFC and rename the sysctl knob to
accept_untracked_na.

Fixes: f9a2fb73318e ("net/ipv6: Introduce accept_unsolicited_na knob to implement router-side changes for RFC9131")
Signed-off-by: Arun Ajith S <aajith@arista.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20220530101414.65439-1-aajith@arista.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

random32: use real rng for non-deterministic randomness

random32.c has two random number generators in it: one that is meant to
be used deterministically, with some predefined seed, and one that does
the same exact thing as random.c, except does it poorly. The first one
has some use cases. The second one no longer does and can be replaced
with calls to random.c's proper random number generator.

The relatively recent siphash-based bad random32.c code was added in
response to concerns that the prior random32.c was too deterministic.
Out of fears that random.c was (at the time) too slow, this code was
anonymously contributed. Then out of that emerged a kind of shadow
entropy gathering system, with its own tentacles throughout various net
code, added willy nilly.

Stop👏making👏bespoke👏random👏number👏generators👏.

Fortunately, recent advances in random.c mean that we can stop playing
with this sketchiness, and just use get_random_u32(), which is now fast
enough. In micro benchmarks using RDPMC, I'm seeing the same median
cycle count between the two functions, with the mean being _slightly_
higher due to batches refilling (which we can optimize further need be).
However, when doing *real* benchmarks of the net functions that actually
use these random numbers, the mean cycles actually *decreased* slightly
(with the median still staying the same), likely because the additional
prandom code means icache misses and complexity, whereas random.c is
generally already being used by something else nearby.

The biggest benefit of this is that there are many users of prandom who
probably should be using cryptographically secure random numbers. This
makes all of those accidental cases become secure by just flipping a
switch. Later on, we can do a tree-wide cleanup to remove the static
inline wrapper functions that this commit adds.

There are also some low-ish hanging fruits for making this even faster
in the future: a get_random_u16() function for use in the networking
stack will give a 2x performance boost there, using SIMD for ChaCha20
will let us compute 4 or 8 or 16 blocks of output in parallel, instead
of just one, giving us large buffers for cheap, and introducing a
get_random_*_bh() function that assumes irqs are already disabled will
shave off a few cycles for ordinary calls. These are things we can chip
away at down the road.

Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

memcg: accounting for objects allocated for new netdevice

Creating a new netdevice allocates at least ~50Kb of memory for various
kernel objects, but only ~5Kb of them are accounted to memcg. As a result,
creating an unlimited number of netdevice inside a memcg-limited container
does not fall within memcg restrictions, consumes a significant part
of the host's memory, can cause global OOM and lead to random kills of
host processes.

The main consumers of non-accounted memory are:
~10Kb 80+ kernfs nodes
~6Kb ipv6_add_dev() allocations
6Kb __register_sysctl_table() allocations
4Kb neigh_sysctl_register() allocations
4Kb __devinet_sysctl_register() allocations
4Kb __addrconf_sysctl_register() allocations

Accounting of these objects allows to increase the share of memcg-related
memory up to 60-70% (~38Kb accounted vs ~54Kb total for dummy netdevice
on typical VM with default Fedora 35 kernel) and this should be enough
to somehow protect the host from misuse inside container.

Other related objects are quite small and may not be taken into account
to minimize the expected performance degradation.

It should be separately mentonied ~300 bytes of percpu allocation
of struct ipstats_mib in snmp6_alloc_dev(), on huge multi-cpu nodes
it can become the main consumer of memory.

This patch does not enables kernfs accounting as it affects
other parts of the kernel and should be discussed separately.
However, even without kernfs, this patch significantly improves the
current situation and allows to take into account more than half
of all netdevice allocations.

Signed-off-by: Vasily Averin <vvs@openvz.org>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/354a0a5f-9ec3-a25c-3215-304eab2157bc@openvz.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6: Don't send rs packets to the interface of ARPHRD_TUNNEL

ARPHRD_TUNNEL interface can't process rs packets
and will generate TX errors

ex:
ip tunnel add ethn mode ipip local 192.168.1.1 remote 192.168.1.2
ifconfig ethn x.x.x.x

ethn: flags=209<UP,POINTOPOINT,RUNNING,NOARP> mtu 1480
inet x.x.x.x netmask 255.255.255.255 destination x.x.x.x
inet6 fe80::5efe:ac1e:3cdb prefixlen 64 scopeid 0x20<link>
tunnel txqueuelen 1000 (IPIP Tunnel)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 3 dropped 0 overruns 0 carrier 0 collisions 0

Signed-off-by: jianghaoran <jianghaoran@kylinos.cn>
Link: https://lore.kernel.org/r/20220429053802.246681-1-jianghaoran@kylinos.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/ipv6: Enforce limits for accept_unsolicited_na sysctl

Fix mistake in the original patch where limits were specified but the
handler didn't take care of the limits.

Signed-off-by: Arun Ajith S <aajith@arista.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Introduce accept_unsolicited_na knob to implement router-side changes for RFC9131

Add a new neighbour cache entry in STALE state for routers on receiving
an unsolicited (gratuitous) neighbour advertisement with
target link-layer-address option specified.
This is similar to the arp_accept configuration for IPv4.
A new sysctl endpoint is created to turn on this behaviour:
/proc/sys/net/ipv6/conf/interface/accept_unsolicited_na.

Signed-off-by: Arun Ajith S <aajith@arista.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: fix locking issues with loops over idev->addr_list

idev->addr_list needs to be protected by idev->lock. However, it is not
always possible to do so while iterating and performing actions on
inet6_ifaddr instances. For example, multiple functions (like
addrconf_{join,leave}_anycast) eventually call down to other functions
that acquire the idev->lock. The current code temporarily unlocked the
idev->lock during the loops, which can cause race conditions. Moving the
locks up is also not an appropriate solution as the ordering of lock
acquisition will be inconsistent with for example mc_lock.

This solution adds an additional field to inet6_ifaddr that is used
to temporarily add the instances to a temporary list while holding
idev->lock. The temporary list can then be traversed without holding
idev->lock. This change was done in two places. In addrconf_ifdown, the
list_for_each_entry_safe variant of the list loop is also no longer
necessary as there is no deletion within that specific loop.

Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Niels Dossche <dossche.niels@gmail.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20220403231523.45843-1-dossche.niels@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: Add new protocol attribute to IP addresses

This patch adds a new protocol attribute to IPv4 and IPv6 addresses.
Inspiration was taken from the protocol attribute of routes. User space
applications like iproute2 can set/get the protocol with the Netlink API.

The attribute is stored as an 8-bit unsigned integer.

The protocol attribute is set by kernel for these categories:

- IPv4 and IPv6 loopback addresses
- IPv6 addresses generated from router announcements
- IPv6 link local addresses

User space may pass custom protocols, not defined by the kernel.

Grouping addresses on their origin is useful in scenarios where you want
to distinguish between addresses based on who added them, e.g. kernel
vs. user space.

Tagging addresses with a string label is an existing feature that could be
used as a solution. Unfortunately the max length of a label is
15 characters, and for compatibility reasons the label must be prefixed
with the name of the device followed by a colon. Since device names also
have a max length of 15 characters, only -1 characters is guaranteed to be
available for any origin tag, which is not that much.

A reference implementation of user space setting and getting protocols
is available for iproute2:

https://github.com/westermo/iproute2/commit/9a6ea18bd79f47f293e5edc7780f315ea42ff540

Signed-off-by: Jacques de Laval <Jacques.De.Laval@westermo.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20220217150202.80802-1-Jacques.De.Laval@westermo.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6/addrconf: ensure addrconf_verify_rtnl() has completed

Before freeing the hash table in addrconf_exit_net(),
we need to make sure the work queue has completed,
or risk NULL dereference or UAF.

Thus, use cancel_delayed_work_sync() to enforce this.
We do not hold RTNL in addrconf_exit_net(), making this safe.

Fixes: 8805d13ff1b2 ("ipv6/addrconf: use one delayed work per netns")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20220216182037.3742-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6: blackhole_netdev needs snmp6 counters

Whenever rt6_uncached_list_flush_dev() swaps rt->rt6_idev
to the blackhole device, parts of IPv6 stack might still need
to increment one SNMP counter.

Root cause, patch from Ido, changelog from Eric :)

This bug suggests that we need to audit rt->rt6_idev usages
and make sure they are properly using RCU protection.

Fixes: e5f80fcf869a ("ipv6: give an IPv6 dev to blackhole_netdev")
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: give an IPv6 dev to blackhole_netdev

IPv6 addrconf notifiers wants the loopback device to
be the last device being dismantled at netns deletion.

This caused many limitations and work arounds.

Back in linux-5.3, Mahesh added a per host blackhole_netdev
that can be used whenever we need to make sure objects no longer
refer to a disappearing device.

If we attach to blackhole_netdev an ip6_ptr (allocate an idev),
then we can use this special device (which is never freed)
in place of the loopback_dev (which can be freed).

This will permit improvements in netdev_run_todo() and other parts
of the stack where had steps to make sure loopback_dev was
the last device to disappear.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6/addrconf: switch to per netns inet6_addr_lst hash table

IPv6 does not scale very well with the number of IPv6 addresses.
It uses a global (shared by all netns) hash table with 256 buckets.

Some functions like addrconf_verify_rtnl() and addrconf_ifdown()
have to iterate all addresses in the hash table.

I have seen addrconf_verify_rtnl() holding the cpu for 10ms or more.

Switch to the per netns hashtable (and spinlock) added
in prior patches.

This considerably speeds up netns dismantle times on hosts
with thousands of netns. This also has an impact
on regular (fast path) IPv6 processing.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6/addrconf: use one delayed work per netns

Next step for using per netns inet6_addr_lst
is to have per netns work item to ultimately
call addrconf_verify_rtnl() and addrconf_verify()
with a new 'struct net*' argument.

Everything is still using the global inet6_addr_lst[] table.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6/addrconf: allocate a per netns hash table

Add a per netns hash table and a dedicated spinlock,
first step to get rid of the global inet6_addr_lst[] one.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ip6mr: fix use-after-free in ip6mr_sk_done()

Apparently addrconf_exit_net() is called before igmp6_net_exit()
and ndisc_net_exit() at netns dismantle time:

net_namespace: call ip6table_mangle_net_exit()
net_namespace: call ip6_tables_net_exit()
net_namespace: call ipv6_sysctl_net_exit()
net_namespace: call ioam6_net_exit()
net_namespace: call seg6_net_exit()
net_namespace: call ping_v6_proc_exit_net()
net_namespace: call tcpv6_net_exit()
ip6mr_sk_done sk=ffffa354c78a74c0
net_namespace: call ipv6_frags_exit_net()
net_namespace: call addrconf_exit_net()
net_namespace: call ip6addrlbl_net_exit()
net_namespace: call ip6_flowlabel_net_exit()
net_namespace: call ip6_route_net_exit_late()
net_namespace: call fib6_rules_net_exit()
net_namespace: call xfrm6_net_exit()
net_namespace: call fib6_net_exit()
net_namespace: call ip6_route_net_exit()
net_namespace: call ipv6_inetpeer_exit()
net_namespace: call if6_proc_net_exit()
net_namespace: call ipv6_proc_exit_net()
net_namespace: call udplite6_proc_exit_net()
net_namespace: call raw6_exit_net()
net_namespace: call igmp6_net_exit()
ip6mr_sk_done sk=ffffa35472b2a180
ip6mr_sk_done sk=ffffa354c78a7980
net_namespace: call ndisc_net_exit()
ip6mr_sk_done sk=ffffa35472b2ab00
net_namespace: call ip6mr_net_exit()
net_namespace: call inet6_net_exit()

This was fine because ip6mr_sk_done() would not reach the point decreasing
net->ipv6.devconf_all->mc_forwarding until my patch in ip6mr_sk_done().

To fix this without changing struct pernet_operations ordering,
we can clear net->ipv6.devconf_dflt and net->ipv6.devconf_all
when they are freed from addrconf_exit_net()

BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:71 [inline]
BUG: KASAN: use-after-free in atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]
BUG: KASAN: use-after-free in ip6mr_sk_done+0x11b/0x410 net/ipv6/ip6mr.c:1578
Read of size 4 at addr ffff88801ff08688 by task kworker/u4:4/963

CPU: 0 PID: 963 Comm: kworker/u4:4 Not tainted 5.17.0-rc2-syzkaller-00650-g5a8fb33e5305 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description.constprop.0.cold+0x8d/0x336 mm/kasan/report.c:255
__kasan_report mm/kasan/report.c:442 [inline]
kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
check_region_inline mm/kasan/generic.c:183 [inline]
kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
instrument_atomic_read include/linux/instrumented.h:71 [inline]
atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]
ip6mr_sk_done+0x11b/0x410 net/ipv6/ip6mr.c:1578
rawv6_close+0x58/0x80 net/ipv6/raw.c:1201
inet_release+0x12e/0x280 net/ipv4/af_inet.c:428
inet6_release+0x4c/0x70 net/ipv6/af_inet6.c:478
__sock_release net/socket.c:650 [inline]
sock_release+0x87/0x1b0 net/socket.c:678
inet_ctl_sock_destroy include/net/inet_common.h:65 [inline]
igmp6_net_exit+0x6b/0x170 net/ipv6/mcast.c:3173
ops_exit_list+0xb0/0x170 net/core/net_namespace.c:168
cleanup_net+0x4ea/0xb00 net/core/net_namespace.c:600
process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
worker_thread+0x657/0x1110 kernel/workqueue.c:2454
kthread+0x2e9/0x3a0 kernel/kthread.c:377
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>

Fixes: f2f2325ec799 ("ip6mr: ip6mr_sk_done() can exit early in common cases")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: make mc_forwarding atomic

This fixes minor data-races in ip6_mc_input() and
batadv_mcast_mla_rtr_flags_softif_get_ipv6()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipv6: ensure we call ipv6_mc_down() at most once

There are two reasons for addrconf_notify() to be called with NETDEV_DOWN:
either the network device is actually going down, or IPv6 was disabled
on the interface.

If either of them stays down while the other is toggled, we repeatedly
call the code for NETDEV_DOWN, including ipv6_mc_down(), while never
calling the corresponding ipv6_mc_up() in between. This will cause a
new entry in idev->mc_tomb to be allocated for each multicast group
the interface is subscribed to, which in turn leaks one struct ifmcaddr6
per nontrivial multicast group the interface is subscribed to.

The following reproducer will leak at least $n objects:

ip addr add ff2e::4242/32 dev eth0 autojoin
sysctl -w net.ipv6.conf.eth0.disable_ipv6=1
for i in $(seq 1 $n); do
ip link set up eth0; ip link set down eth0
done

Joining groups with IPV6_ADD_MEMBERSHIP (unprivileged) or setting the
sysctl net.ipv6.conf.eth0.forwarding to 1 (=> subscribing to ff02::2)
can also be used to create a nontrivial idev->mc_list, which will the
leak objects with the right up-down-sequence.

Based on both sources for NETDEV_DOWN events the interface IPv6 state
should be considered:

- not ready if the network interface is not ready OR IPv6 is disabled
for it
- ready if the network interface is ready AND IPv6 is enabled for it

The functions ipv6_mc_up() and ipv6_down() should only be run when this
state changes.

Implement this by remembering when the IPv6 state is ready, and only
run ipv6_mc_down() if it actually changed from ready to not ready.

The other direction (not ready -> ready) already works correctly, as:

- the interface notification triggered codepath for NETDEV_UP /
NETDEV_CHANGE returns early if ipv6 is disabled, and
- the disable_ipv6=0 triggered codepath skips fully initializing the
interface as long as addrconf_link_ready(dev) returns false
- calling ipv6_mc_up() repeatedly does not leak anything

Fixes: 3ce62a84d53c ("ipv6: exit early in addrconf_notify() if IPv6 is disabled")
Signed-off-by: Johannes Nixdorf <j.nixdorf@avm.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: prevent a possible race condition with lifetimes

valid_lft, prefered_lft and tstamp are always accessed under the lock
"lock" in other places. Reading these without taking the lock may result
in inconsistencies regarding the calculation of the valid and preferred
variables since decisions are taken on these fields for those variables.

Signed-off-by: Niels Dossche <dossche.niels@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Niels Dossche <niels.dossche@ugent.be>
Link: https://lore.kernel.org/r/20220223131954.6570-1-niels.dossche@ugent.be
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6: mcast: use rcu-safe version of ipv6_get_lladdr()

Some time ago 8965779d2c0e ("ipv6,mcast: always hold idev->lock before mca_lock")
switched ipv6_get_lladdr() to __ipv6_get_lladdr(), which is rcu-unsafe
version. That was OK, because idev->lock was held for these codepaths.

In 88e2ca308094 ("mld: convert ifmcaddr6 to RCU") these external locks were
removed, so we probably need to restore the original rcu-safe call.

Otherwise, we occasionally get a machine crashed/stalled with the following
in dmesg:

[ 3405.966610][T230589] general protection fault, probably for non-canonical address 0xdead00000000008c: 0000 [#1] SMP NOPTI
[ 3405.982083][T230589] CPU: 44 PID: 230589 Comm: kworker/44:3 Tainted: G O 5.15.19-cloudflare-2022.2.1 #1
[ 3405.998061][T230589] Hardware name: SUPA-COOL-SERV
[ 3406.009552][T230589] Workqueue: mld mld_ifc_work
[ 3406.017224][T230589] RIP: 0010:__ipv6_get_lladdr+0x34/0x60
[ 3406.025780][T230589] Code: 57 10 48 83 c7 08 48 89 e5 48 39 d7 74 3e 48 8d 82 38 ff ff ff eb 13 48 8b 90 d0 00 00 00 48 8d 82 38 ff ff ff 48 39 d7 74 22 <66> 83 78 32 20 77 1b 75 e4 89 ca 23 50 2c 75 dd 48 8b 50 08 48 8b
[ 3406.055748][T230589] RSP: 0018:ffff94e4b3fc3d10 EFLAGS: 00010202
[ 3406.065617][T230589] RAX: dead00000000005a RBX: ffff94e4b3fc3d30 RCX: 0000000000000040
[ 3406.077477][T230589] RDX: dead000000000122 RSI: ffff94e4b3fc3d30 RDI: ffff8c3a31431008
[ 3406.089389][T230589] RBP: ffff94e4b3fc3d10 R08: 0000000000000000 R09: 0000000000000000
[ 3406.101445][T230589] R10: ffff8c3a31430000 R11: 000000000000000b R12: ffff8c2c37887100
[ 3406.113553][T230589] R13: ffff8c3a39537000 R14: 00000000000005dc R15: ffff8c3a31431000
[ 3406.125730][T230589] FS: 0000000000000000(0000) GS:ffff8c3b9fc80000(0000) knlGS:0000000000000000
[ 3406.138992][T230589] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3406.149895][T230589] CR2: 00007f0dfea1db60 CR3: 000000387b5f2000 CR4: 0000000000350ee0
[ 3406.162421][T230589] Call Trace:
[ 3406.170235][T230589] <TASK>
[ 3406.177736][T230589] mld_newpack+0xfe/0x1a0
[ 3406.186686][T230589] add_grhead+0x87/0xa0
[ 3406.195498][T230589] add_grec+0x485/0x4e0
[ 3406.204310][T230589] ? newidle_balance+0x126/0x3f0
[ 3406.214024][T230589] mld_ifc_work+0x15d/0x450
[ 3406.223279][T230589] process_one_work+0x1e6/0x380
[ 3406.232982][T230589] worker_thread+0x50/0x3a0
[ 3406.242371][T230589] ? rescuer_thread+0x360/0x360
[ 3406.252175][T230589] kthread+0x127/0x150
[ 3406.261197][T230589] ? set_kthread_struct+0x40/0x40
[ 3406.271287][T230589] ret_from_fork+0x22/0x30
[ 3406.280812][T230589] </TASK>
[ 3406.288937][T230589] Modules linked in: ... [last unloaded: kheaders]
[ 3406.476714][T230589] ---[ end trace 3525a7655f2f3b9e ]---

Fixes: 88e2ca308094 ("mld: convert ifmcaddr6 to RCU")
Reported-by: David Pinilla Caparros <dpini@cloudflare.com>
Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Revert "ipv6: Honor all IPv6 PIO Valid Lifetime values"

This reverts commit b75326c201242de9495ff98e5d5cff41d7fc0d9d.

This commit breaks Linux compatibility with USGv6 tests. The RFC this
commit was based on is actually an expired draft: no published RFC
currently allows the new behaviour it introduced.

Without full IETF endorsement, the flash renumbering scenario this
patch was supposed to enable is never going to work, as other IPv6
equipements on the same LAN will keep the 2 hours limit.

Fixes: b75326c20124 ("ipv6: Honor all IPv6 PIO Valid Lifetime values")
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: add net device refcount tracker to struct inet6_dev

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ndisc: introduce ndisc_evict_nocarrier sysctl parameter

In most situations the neighbor discovery cache should be cleared on a
NOCARRIER event which is currently done unconditionally. But for wireless
roams the neighbor discovery cache can and should remain intact since
the underlying network has not changed.

This patch introduces a sysctl option ndisc_evict_nocarrier which can
be disabled by a wireless supplicant during a roam. This allows packets
to be sent after a roam immediately without having to wait for
neighbor discovery.

A user reported roughly a 1 second delay after a roam before packets
could be sent out (note, on IPv4). This delay was due to the ARP
cache being cleared. During testing of this same scenario using IPv6
no delay was noticed, but regardless there is no reason to clear
the ndisc cache for wireless roams.

Signed-off-by: James Prestwood <prestwoj@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

gre/sit: Don't generate link-local addr if addr_gen_mode is IN6_ADDR_GEN_MODE_NONE

When addr_gen_mode is set to IN6_ADDR_GEN_MODE_NONE, the link-local addr
should not be generated. But it isn't the case for GRE (as well as GRE6)
and SIT tunnels. Make it so that tunnels consider the addr_gen_mode,
especially for IN6_ADDR_GEN_MODE_NONE.

Do this in add_v4_addrs() to cover both GRE and SIT only if the addr
scope is link.

Signed-off-by: Stephen Suryaputra <ssuryaextr@gmail.com>
Acked-by: Antonio Quartulli <a@unstable.cc>
Link: https://lore.kernel.org/r/20211020200618.467342-1-ssuryaextr@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6: constify dev_addr passing

In preparation for netdev->dev_addr being constant
make all relevant arguments in ndisc constant.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ip/ip6_gre: use the same logic as SIT interfaces when computing v6LL address

GRE interfaces are not Ether-like and therefore it is not
possible to generate the v6LL address the same way as (for example)
GRETAP devices.

With default settings, a GRE interface will attempt generating its v6LL
address using the EUI64 approach, but this will fail when the local
endpoint of the GRE tunnel is set to "any". In this case the GRE
interface will end up with no v6LL address, thus violating RFC4291.

SIT interfaces already implement a different logic to ensure that a v6LL
address is always computed.

Change the GRE v6LL generation logic to follow the same approach as SIT.
This way GRE interfaces will always have a v6LL address as well.

Behaviour of GRETAP interfaces has not been changed as they behave like
classic Ether-like interfaces.

To avoid code duplication sit_add_v4_addrs() has been renamed to
add_v4_addrs() and adapted to handle also the IP6GRE/GRE cases.

Signed-off-by: Antonio Quartulli <a@unstable.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: add IFLA_INET6_RA_MTU to expose mtu value

The kernel provides a "/proc/sys/net/ipv6/conf/<iface>/mtu"
file, which can temporarily record the mtu value of the last
received RA message when the RA mtu value is lower than the
interface mtu, but this proc has following limitations:

(1) when the interface mtu (/sys/class/net/<iface>/mtu) is
updeated, mtu6 (/proc/sys/net/ipv6/conf/<iface>/mtu) will
be updated to the value of interface mtu;
(2) mtu6 (/proc/sys/net/ipv6/conf/<iface>/mtu) only affect
ipv6 connection, and not affect ipv4.

Therefore, when the mtu option is carried in the RA message,
there will be a problem that the user sometimes cannot obtain
RA mtu value correctly by reading mtu6.

After this patch set, if a RA message carries the mtu option,
you can send a netlink msg which nlmsg_type is RTM_GETLINK,
and then by parsing the attribute of IFLA_INET6_RA_MTU to
get the mtu value carried in the RA message received on the
inet6 device. In addition, you can also get a link notification
when ra_mtu is updated so it doesn't have to poll.

In this way, if the MTU values that the device receives from
the network in the PCO IPv4 and the RA IPv6 procedures are
different, the user can obtain the correct ipv6 ra_mtu value
and compare the value of ra_mtu and ipv4 mtu, then the device
can use the lower MTU value for both IPv4 and IPv6.

Signed-off-by: Rocco Yue <rocco.yue@mediatek.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20210827150412.9267-1-rocco.yue@mediatek.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: Remove redundant if statements

The 'if (dev)' statement already move into dev_{put , hold}, so remove
redundant if statements.

Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: add extack arg for link ops

Pass extack arg to validate_linkmsg and validate_link_af callbacks.
If a netlink attribute has a reject_message, use the extended ack
mechanism to carry the message back to user space.

Signed-off-by: Rocco Yue <rocco.yue@mediatek.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: fix "'ioam6_if_id_max' defined but not used" warn

When compiling without CONFIG_SYSCTL, this warning appears:

net/ipv6/addrconf.c:99:12: error: 'ioam6_if_id_max' defined but not used [-Werror=unused-variable]
99 | static u32 ioam6_if_id_max = U16_MAX;
| ^~~~~~~~~~~~~~~
cc1: all warnings being treated as errors

Simply moving the declaration of this variable under ...

#ifdef CONFIG_SYSCTL

... with other similar variables fixes the issue.

Fixes: 9ee11f0fff20 ("ipv6: ioam: Data plane support for Pre-allocated Trace")
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: ioam: Data plane support for Pre-allocated Trace

Implement support for processing the IOAM Pre-allocated Trace with IPv6,
see [1] and [2]. Introduce a new IPv6 Hop-by-Hop TLV option, see IANA [3].

A new per-interface sysctl is introduced. The value is a boolean to accept (=1)
or ignore (=0, by default) IPv6 IOAM options on ingress for an interface:
- net.ipv6.conf.XXX.ioam6_enabled

Two other sysctls are introduced to define IOAM IDs, represented by an integer.
They are respectively per-namespace and per-interface:
- net.ipv6.ioam6_id
- net.ipv6.conf.XXX.ioam6_id

The value of the first one represents the IOAM ID of the node itself (u32; max
and default value = U32_MAX>>8, due to hop limit concatenation) while the other
represents the IOAM ID of an interface (u16; max and default value = U16_MAX).

Each "ioam6_id" sysctl has a "_wide" equivalent:
- net.ipv6.ioam6_id_wide
- net.ipv6.conf.XXX.ioam6_id_wide

The value of the first one represents the wide IOAM ID of the node itself (u64;
max and default value = U64_MAX>>8, due to hop limit concatenation) while the
other represents the wide IOAM ID of an interface (u32; max and default value
= U32_MAX).

The use of short and wide equivalents is not exclusive, a deployment could
choose to leverage both. For example, net.ipv6.conf.XXX.ioam6_id (short format)
could be an identifier for a physical interface, whereas
net.ipv6.conf.XXX.ioam6_id_wide (wide format) could be an identifier for a
logical sub-interface. Documentation about new sysctls is provided at the end
of this patchset.

Two relativistic hash tables are used: one for IOAM namespaces, the other for
IOAM schemas. A namespace can only have a single active schema and a schema
can only be attached to a single namespace (1:1 relationship).

[1] https://tools.ietf.org/html/draft-ietf-ippm-ioam-ipv6-options
[2] https://tools.ietf.org/html/draft-ietf-ippm-ioam-data
[3] https://www.iana.org/assignments/ipv6-parameters/ipv6-parameters.xhtml#ipv6-parameters-2

Signed-off-by: Justin Iurman <justin.iurman@uliege.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

memcg: enable accounting for IP address and routing-related objects

An netadmin inside container can use 'ip a a' and 'ip r a'
to assign a large number of ipv4/ipv6 addresses and routing entries
and force kernel to allocate megabytes of unaccounted memory
for long-lived per-netdevice related kernel objects:
'struct in_ifaddr', 'struct inet6_ifaddr', 'struct fib6_node',
'struct rt6_info', 'struct fib_rules' and ip_fib caches.

These objects can be manually removed, though usually they lives
in memory till destroy of its net namespace.

It makes sense to account for them to restrict the host's memory
consumption from inside the memcg-limited container.

One of such objects is the 'struct fib6_node' mostly allocated in
net/ipv6/route.c::__ip6_ins_rt() inside the lock_bh()/unlock_bh() section:

write_lock_bh(&table->tb6_lock);
err = fib6_add(&table->tb6_root, rt, info, mxc);
write_unlock_bh(&table->tb6_lock);

In this case it is not enough to simply add SLAB_ACCOUNT to corresponding
kmem cache. The proper memory cgroup still cannot be found due to the
incorrect 'in_interrupt()' check used in memcg_kmem_bypass().

Obsoleted in_interrupt() does not describe real execution context properly.
>From include/linux/preempt.h:

The following macros are deprecated and should not be used in new code:
in_interrupt() - We're in NMI,IRQ,SoftIRQ context or have BH disabled

To verify the current execution context new macro should be used instead:
in_task() - We're in task context

Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: remove unnecessary local variable

The local variable "struct net *net" in the two functions of
inet6_rtm_getaddr() and inet6_dump_addr() are actually useless,
so remove them.

Signed-off-by: Rocco Yue <rocco.yue@mediatek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: align code with context

The Tab key is used three times, causing the code block to
be out of alignment with the context.

Signed-off-by: Rocco Yue <rocco.yue@mediatek.com>
Link: https://lore.kernel.org/r/20210530113811.8817-1-rocco.yue@mediatek.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipv4: Remove unneed BUG() function

When 'nla_parse_nested_deprecated' failed, it's no need to
BUG() here, return -EINVAL is ok.

Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

mld: fix suspicious RCU usage in __ipv6_dev_mc_dec()

__ipv6_dev_mc_dec() internally uses sleepable functions so that caller
must not acquire atomic locks. But caller, which is addrconf_verify_rtnl()
acquires rcu_read_lock_bh().
So this warning occurs in the __ipv6_dev_mc_dec().

Test commands:
ip netns add A
ip link add veth0 type veth peer name veth1
ip link set veth1 netns A
ip link set veth0 up
ip netns exec A ip link set veth1 up
ip a a 2001:db8::1/64 dev veth0 valid_lft 2 preferred_lft 1

Splat looks like:
============================
WARNING: suspicious RCU usage
5.12.0-rc6+ #515 Not tainted
-----------------------------
kernel/sched/core.c:8294 Illegal context switch in RCU-bh read-side
critical section!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
4 locks held by kworker/4:0/1997:
#0: ffff88810bd72d48 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at:
process_one_work+0x761/0x1440
#1: ffff888105c8fe00 ((addr_chk_work).work){+.+.}-{0:0}, at:
process_one_work+0x795/0x1440
#2: ffffffffb9279fb0 (rtnl_mutex){+.+.}-{3:3}, at:
addrconf_verify_work+0xa/0x20
#3: ffffffffb8e30860 (rcu_read_lock_bh){....}-{1:2}, at:
addrconf_verify_rtnl+0x23/0xc60

stack backtrace:
CPU: 4 PID: 1997 Comm: kworker/4:0 Not tainted 5.12.0-rc6+ #515
Workqueue: ipv6_addrconf addrconf_verify_work
Call Trace:
dump_stack+0xa4/0xe5
___might_sleep+0x27d/0x2b0
__mutex_lock+0xc8/0x13f0
? lock_downgrade+0x690/0x690
? __ipv6_dev_mc_dec+0x49/0x2a0
? mark_held_locks+0xb7/0x120
? mutex_lock_io_nested+0x1270/0x1270
? lockdep_hardirqs_on_prepare+0x12c/0x3e0
? _raw_spin_unlock_irqrestore+0x47/0x50
? trace_hardirqs_on+0x41/0x120
? __wake_up_common_lock+0xc9/0x100
? __wake_up_common+0x620/0x620
? memset+0x1f/0x40
? netlink_broadcast_filtered+0x2c4/0xa70
? __ipv6_dev_mc_dec+0x49/0x2a0
__ipv6_dev_mc_dec+0x49/0x2a0
? netlink_broadcast_filtered+0x2f6/0xa70
addrconf_leave_solict.part.64+0xad/0xf0
? addrconf_join_solict.part.63+0xf0/0xf0
? nlmsg_notify+0x63/0x1b0
__ipv6_ifa_notify+0x22c/0x9c0
? inet6_fill_ifaddr+0xbe0/0xbe0
? lockdep_hardirqs_on_prepare+0x12c/0x3e0
? __local_bh_enable_ip+0xa5/0xf0
? ipv6_del_addr+0x347/0x870
ipv6_del_addr+0x3b1/0x870
? addrconf_ifdown+0xfe0/0xfe0
? rcu_read_lock_any_held.part.27+0x20/0x20
addrconf_verify_rtnl+0x8a9/0xc60
addrconf_verify_work+0xf/0x20
process_one_work+0x84c/0x1440

In order to avoid this problem, it uses rcu_read_unlock_bh() for
a short time. RCU is used for avoiding freeing
ifp(struct *inet6_ifaddr) while ifp is being used. But this will
not be released even if rcu_read_unlock_bh() is used.
Because before rcu_read_unlock_bh(), it uses in6_ifa_hold(ifp).
So this is safe.

Fixes: 63ed8de4be81 ("mld: add mc_lock for protecting per-interface mld data")
Suggested-by: Eric Dumazet <edumazet@google.com>
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: addrconf.c: Fix a typo

s/Identifers/Identifiers/

Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

mld: convert ifmcaddr6 to RCU

The ifmcaddr6 has been protected by inet6_dev->lock(rwlock) so that
the critical section is atomic context. In order to switch this context,
changing locking is needed. The ifmcaddr6 actually already protected by
RTNL So if it's converted to use RCU, its control path context can be
switched to sleepable.

Suggested-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: report errors for iftoken via netlink extack

Setting iftoken can fail for several different reasons but there
and there was no report to user as to the cause. Add netlink
extended errors to the processing of the request.

This requires adding additional argument through rtnl_af_ops
set_link_af callback.

Reported-by: Hongren Zheng <li@zenithal.me>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: allow user to set metric on default route learned via Router Advertisement

For IPv4, default route is learned via DHCPv4 and user is allowed to change
metric using config etc/network/interfaces. But for IPv6, default route can
be learned via RA, for which, currently a fixed metric value 1024 is used.

Ideally, user should be able to configure metric on default route for IPv6
similar to IPv4. This patch adds sysctl for the same.

Logs:

For IPv4:

Config in etc/network/interfaces:
auto eth0
iface eth0 inet dhcp
metric 4261413864

IPv4 Kernel Route Table:
$ ip route list
default via 172.21.47.1 dev eth0 metric 4261413864

FRR Table, if a static route is configured:
[In real scenario, it is useful to prefer BGP learned default route over DHCPv4 default route.]
Codes: K - kernel route, C - connected, S - static, R - RIP,
O - OSPF, I - IS-IS, B - BGP, P - PIM, E - EIGRP, N - NHRP,
T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
> - selected route, * - FIB route

S>* 0.0.0.0/0 [20/0] is directly connected, eth0, 00:00:03
K 0.0.0.0/0 [254/1000] via 172.21.47.1, eth0, 6d08h51m

i.e. User can prefer Default Router learned via Routing Protocol in IPv4.
Similar behavior is not possible for IPv6, without this fix.

After fix [for IPv6]:
sudo sysctl -w net.ipv6.conf.eth0.net.ipv6.conf.eth0.ra_defrtr_metric=1996489705

IP monitor: [When IPv6 RA is received]
default via fe80::xx16:xxxx:feb3:ce8e dev eth0 proto ra metric 1996489705 pref high

Kernel IPv6 routing table
$ ip -6 route list
default via fe80::be16:65ff:feb3:ce8e dev eth0 proto ra metric 1996489705 expires 21sec hoplimit 64 pref high

FRR Table, if a static route is configured:
[In real scenario, it is useful to prefer BGP learned default route over IPv6 RA default route.]
Codes: K - kernel route, C - connected, S - static, R - RIPng,
O - OSPFv3, I - IS-IS, B - BGP, N - NHRP, T - Table,
v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
> - selected route, * - FIB route

S>* ::/0 [20/0] is directly connected, eth0, 00:00:06
K ::/0 [119/1001] via fe80::xx16:xxxx:feb3:ce8e, eth0, 6d07h43m

If the metric is changed later, the effect will be seen only when next IPv6
RA is received, because the default route must be fully controlled by RA msg.
Below metric is changed from 1996489705 to 1996489704.

$ sudo sysctl -w net.ipv6.conf.eth0.ra_defrtr_metric=1996489704
net.ipv6.conf.eth0.ra_defrtr_metric = 1996489704

IP monitor:
[On next IPv6 RA msg, Kernel deletes prev route and installs new route with updated metric]

Deleted default via fe80::xx16:xxxx:feb3:ce8e dev eth0 proto ra metric 1996489705 expires 3sec hoplimit 64 pref high
default via fe80::xx16:xxxx:feb3:ce8e dev eth0 proto ra metric 1996489704 pref high

Signed-off-by: Praveen Chaudhary <pchaudhary@linkedin.com>
Signed-off-by: Zhenggen Xu <zxu@linkedin.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20210125214430.24079-1-pchaudhary@linkedin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6: set multicast flag on the multicast route

The multicast route ff00::/8 is created with type RTN_UNICAST:

$ ip -6 -d route
unicast ::1 dev lo proto kernel scope global metric 256 pref medium
unicast fe80::/64 dev eth0 proto kernel scope global metric 256 pref medium
unicast ff00::/8 dev eth0 proto kernel scope global metric 256 pref medium

Set the type to RTN_MULTICAST which is more appropriate.

Fixes: e8478e80e5a7 ("net/ipv6: Save route type in rt6_info")
Signed-off-by: Matteo Croce <mcroce@microsoft.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6: create multicast route with RTPROT_KERNEL

The ff00::/8 multicast route is created without specifying the fc_protocol
field, so the default RTPROT_BOOT value is used:

$ ip -6 -d route
unicast ::1 dev lo proto kernel scope global metric 256 pref medium
unicast fe80::/64 dev eth0 proto kernel scope global metric 256 pref medium
unicast ff00::/8 dev eth0 proto boot scope global metric 256 pref medium

As the documentation says, this value identifies routes installed during
boot, but the route is created when interface is set up.
Change the value to RTPROT_KERNEL which is a better value.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Matteo Croce <mcroce@microsoft.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6: Fix error path to cancel the meseage

genlmsg_cancel() needs to be called in the error path of
inet6_fill_ifmcaddr and inet6_fill_ifacaddr to cancel
the message.

Fixes: 6ecf4c37eb3e ("ipv6: enable IFA_TARGET_NETNSID for RTM_GETADDR")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com>
Link: https://lore.kernel.org/r/20201112080950.1476302-1-zhangqilong3@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipv6: For kerneldoc warnings with W=1

net/ipv6/addrconf.c:2005: warning: Function parameter or member 'dev' not described in 'ipv6_dev_find'
net/ipv6/ip6_vti.c:138: warning: Function parameter or member 'ip6n' not described in 'vti6_tnl_bucket'
net/ipv6/ip6_tunnel.c:218: warning: Function parameter or member 'ip6n' not described in 'ip6_tnl_bucket'
net/ipv6/ip6_tunnel.c:238: warning: Function parameter or member 'ip6n' not described in 'ip6_tnl_link'
net/ipv6/ip6_tunnel.c:254: warning: Function parameter or member 'ip6n' not described in 'ip6_tnl_unlink'
net/ipv6/ip6_tunnel.c:427: warning: Function parameter or member 'raw' not described in 'ip6_tnl_parse_tlv_enc_lim'
net/ipv6/ip6_tunnel.c:499: warning: Function parameter or member 'skb' not described in 'ip6_tnl_err'
net/ipv6/ip6_tunnel.c:499: warning: Function parameter or member 'ipproto' not described in 'ip6_tnl_err'
net/ipv6/ip6_tunnel.c:499: warning: Function parameter or member 'opt' not described in 'ip6_tnl_err'
net/ipv6/ip6_tunnel.c:499: warning: Function parameter or member 'type' not described in 'ip6_tnl_err'
net/ipv6/ip6_tunnel.c:499: warning: Function parameter or member 'code' not described in 'ip6_tnl_err'
net/ipv6/ip6_tunnel.c:499: warning: Function parameter or member 'msg' not described in 'ip6_tnl_err'
net/ipv6/ip6_tunnel.c:499: warning: Function parameter or member 'info' not described in 'ip6_tnl_err'
net/ipv6/ip6_tunnel.c:499: warning: Function parameter or member 'offset' not described in 'ip6_tnl_err'

ip6_tnl_err() is an internal function, so remove the kerneldoc. For
the others, add the missing parameters.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20201031183044.1082193-1-andrew@lunn.ch
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv6: some fixes for ipv6_dev_find()

This patch is to do 3 things for ipv6_dev_find():

As David A. noticed,

- rt6_lookup() is not really needed. Different from __ip_dev_find(),
ipv6_dev_find() doesn't have a compatibility problem, so remove it.

As Hideaki suggested,

- "valid" (non-tentative) check for the address is also needed.
ipv6_chk_addr() calls ipv6_chk_addr_and_flags(), which will
traverse the address hash list, but it's heavy to be called
inside ipv6_dev_find(). This patch is to reuse the code of
ipv6_chk_addr_and_flags() for ipv6_dev_find().

- dev parameter is passed into ipv6_dev_find(), as link-local
addresses from user space has sin6_scope_id set and the dev
lookup needs it.

Fixes: 81f6cb31222d ("ipv6: add ipv6_dev_find()")
Suggested-by: YOSHIFUJI Hideaki <hideaki.yoshifuji@miraclelinux.com>
Reported-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: add ipv6_dev_find()

This is to add an ip_dev_find like function for ipv6, used to find
the dev by saddr.

It will be used by TIPC protocol. So also export it.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6/addrconf: use a boolean to choose between UNREGISTER/DOWN

"how" was used as a boolean. Change the type to bool, and improve
variable name

Signed-off-by: Florent Fourcot <florent.fourcot@wifirst.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6/addrconf: call addrconf_ifdown with consistent values

Second parameter of addrconf_ifdown "how" is used as a boolean
internally. It does not make sense to call it with something different
of 0 or 1.

This value is set to 2 in all git history.

Signed-off-by: Florent Fourcot <florent.fourcot@wifirst.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: use ->ndo_tunnel_ctl in addrconf_set_dstaddr

Use the new ->ndo_tunnel_ctl instead of overriding the address limit
and using ->ndo_do_ioctl just to do a pointless user copy.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: streamline addrconf_set_dstaddr

Factor out a addrconf_set_sit_dstaddr helper for the actual work if we
found a SIT device, and only hold the rtnl lock around the device lookup
and that new helper, as there is no point in holding it over a
copy_from_user call.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: stub out even more of addrconf_set_dstaddr if SIT is disabled

There is no point in copying the structure from userspace or looking up
a device if SIT support is not disabled and we'll eventually return
-ENODEV anyway.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

netns: enable to inherit devconf from current netns

The goal is to be able to inherit the initial devconf parameters from the
current netns, ie the netns where this new netns has been created.

This is useful in a containers environment where /proc/sys is read only.
For example, if a pod is created with specifics devconf parameters and has
the capability to create netns, the user expects to get the same parameters
than his 'init_net', which is not the real init_net in this case.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

crypto: lib/sha1 - rename "sha" to "sha1"

The library implementation of the SHA-1 compression function is
confusingly called just "sha_transform()". Alongside it are some "SHA_"
constants and "sha_init()". Presumably these are left over from a time
when SHA just meant SHA-1. But now there are also SHA-2 and SHA-3, and
moreover SHA-1 is now considered insecure and thus shouldn't be used.

Therefore, rename these functions and constants to make it very clear
that they are for SHA-1. Also add a comment to make it clear that these
shouldn't be used.

For the extra-misleadingly named "SHA_MESSAGE_BYTES", rename it to
SHA1_BLOCK_SIZE and define it to just '64' rather than '(512/8)' so that
it matches the same definition in <crypto/sha.h>. This prepares for
merging <linux/cryptohash.h> into <crypto/sha.h>.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

ipv6: Implement draft-ietf-6man-rfc4941bis

Implement the upcoming rev of RFC4941 (IPv6 temporary addresses):
https://tools.ietf.org/html/draft-ietf-6man-rfc4941bis-09

* Reduces the default Valid Lifetime to 2 days
The number of extra addresses employed when Valid Lifetime was
7 days exacerbated the stress caused on network
elements/devices. Additionally, the motivation for temporary
addresses is indeed privacy and reduced exposure. With a
default Valid Lifetime of 7 days, an address that becomes
revealed by active communication is reachable and exposed for
one whole week. The only use case for a Valid Lifetime of 7
days could be some application that is expecting to have long
lived connections. But if you want to have a long lived
connections, you shouldn't be using a temporary address in the
first place. Additionally, in the era of mobile devices, general
applications should nevertheless be prepared and robust to
address changes (e.g. nodes swap wifi <-> 4G, etc.)

* Employs different IIDs for different prefixes
To avoid network activity correlation among addresses configured
for different prefixes

* Uses a simpler algorithm for IID generation
No need to store "history" anywhere

Signed-off-by: Fernando Gont <fgont@si6networks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipv6: new arg skip_notify to ip6_rt_del

Used in subsequent work to skip route delete
notifications on nexthop deletes.

Suggested-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sysctl: pass kernel pointers to ->proc_handler

Instead of having all the sysctl handlers deal with user pointers, which
is rather hairy in terms of the BPF interaction, copy the input to and
from userspace in common code. This also means that the strings are
always NUL-terminated by the common code, making the API a little bit
safer.

As most handler just pass through the data to one of the common handlers
a lot of the changes are mechnical.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

ipv6: Honor all IPv6 PIO Valid Lifetime values

RFC4862 5.5.3 e) prevents received Router Advertisements from reducing
the Valid Lifetime of configured addresses to less than two hours, thus
preventing hosts from reacting to the information provided by a router
that has positive knowledge that a prefix has become invalid.

This patch makes hosts honor all Valid Lifetime values, as per
draft-gont-6man-slaac-renum-06, Section 4.2. This is meant to help
mitigate the problem discussed in draft-ietf-v6ops-slaac-renum.

Note: Attacks aiming at disabling an advertised prefix via a Valid
Lifetime of 0 are not really more harmful than other attacks
that can be performed via forged RA messages, such as those
aiming at completely disabling a next-hop router via an RA that
advertises a Router Lifetime of 0, or performing a Denial of
Service (DoS) attack by advertising illegitimate prefixes via
forged PIOs. In scenarios where RA-based attacks are of concern,
proper mitigations such as RA-Guard [RFC6105] [RFC7113] should
be implemented.

Signed-off-by: Fernando Gont <fgont@si6networks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

neigh: support smaller retrans_time settting

Currently, we limited the retrans_time to be greater than HZ/2. i.e.
setting retrans_time less than 500ms will not work. This makes the user
unable to achieve a more accurate control for bonding arp fast failover.

Update the sanity check to HZ/100, which is 10ms, to let users have more
ability on the retrans_time control.

v3: sync the behavior with IPv6 and update all the timer handler
v2: use HZ instead of hard code number

Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: don't auto-add link-local address to lag ports

Bonding slave and team port devices should not have link-local addresses
automatically added to them, as it can interfere with openvswitch being
able to properly add tc ingress.

Basic reproducer, courtesy of Marcelo:

$ ip link add name bond0 type bond
$ ip link set dev ens2f0np0 master bond0
$ ip link set dev ens2f1np2 master bond0
$ ip link set dev bond0 up
$ ip a s
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens2f0np0: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc
mq master bond0 state UP group default qlen 1000
link/ether 00:0f:53:2f:ea:40 brd ff:ff:ff:ff:ff:ff
5: ens2f1np2: <NO-CARRIER,BROADCAST,MULTICAST,SLAVE,UP> mtu 1500 qdisc
mq master bond0 state DOWN group default qlen 1000
link/ether 00:0f:53:2f:ea:40 brd ff:ff:ff:ff:ff:ff
11: bond0: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> mtu 1500 qdisc
noqueue state UP group default qlen 1000
link/ether 00:0f:53:2f:ea:40 brd ff:ff:ff:ff:ff:ff
inet6 fe80::20f:53ff:fe2f:ea40/64 scope link
valid_lft forever preferred_lft forever

(above trimmed to relevant entries, obviously)

$ sysctl net.ipv6.conf.ens2f0np0.addr_gen_mode=0
net.ipv6.conf.ens2f0np0.addr_gen_mode = 0
$ sysctl net.ipv6.conf.ens2f1np2.addr_gen_mode=0
net.ipv6.conf.ens2f1np2.addr_gen_mode = 0

$ ip a l ens2f0np0
2: ens2f0np0: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc
mq master bond0 state UP group default qlen 1000
link/ether 00:0f:53:2f:ea:40 brd ff:ff:ff:ff:ff:ff
inet6 fe80::20f:53ff:fe2f:ea40/64 scope link tentative
valid_lft forever preferred_lft forever
$ ip a l ens2f1np2
5: ens2f1np2: <NO-CARRIER,BROADCAST,MULTICAST,SLAVE,UP> mtu 1500 qdisc
mq master bond0 state DOWN group default qlen 1000
link/ether 00:0f:53:2f:ea:40 brd ff:ff:ff:ff:ff:ff
inet6 fe80::20f:53ff:fe2f:ea40/64 scope link tentative
valid_lft forever preferred_lft forever

Looks like addrconf_sysctl_addr_gen_mode() bypasses the original "is
this a slave interface?" check added by commit c2edacf80e15, and
results in an address getting added, while w/the proposed patch added,
no address gets added. This simply adds the same gating check to another
code path, and thus should prevent the same devices from erroneously
obtaining an ipv6 link-local address.

Fixes: d35a00b8e33d ("net/ipv6: allow sysctl to change link-local address generation mode")
Reported-by: Moshe Levi <moshele@mellanox.com>
CC: Stephen Hemminger <stephen@networkplumber.org>
CC: Marcelo Ricardo Leitner <mleitner@redhat.com>
CC: netdev@vger.kernel.org
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipv6: add support for rpl sr exthdr

This patch adds rpl source routing receive handling. Everything works
only if sysconf "rpl_seg_enabled" and source routing is enabled. Mostly
the same behaviour as IPv6 segmentation routing. To handle compression
and uncompression a rpl.c file is created which contains the necessary
functionality. The receive handling will also care about IPv6
encapsulated so far it's specified as possible nexthdr in RFC 6554.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

addrconf: add functionality to check on rpl requirements

This patch adds a functionality to addrconf to check on a specific RPL
address configuration. According to RFC 6554:

To detect loops in the SRH, a router MUST determine if the SRH
includes multiple addresses assigned to any interface on that
router. If such addresses appear more than once and are separated by
at least one address not assigned to that router.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

inet: Use fallthrough;

Convert the various uses of fallthrough comments to fallthrough;

Done via script
Link: https://lore.kernel.org/lkml/b56602fcf79f849e733e7b521bb0e17895d390fa.1582230379.git.joe@perches.com/

And by hand:

net/ipv6/ip6_fib.c has a fallthrough comment outside of an #ifdef block
that causes gcc to emit a warning if converted in-place.

So move the new fallthrough; inside the containing #ifdef/#endif too.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6/addrconf: call ipv6_mc_up() for non-Ethernet interface

Rafał found an issue that for non-Ethernet interface, if we down and up
frequently, the memory will be consumed slowly.

The reason is we add allnodes/allrouters addressed in multicast list in
ipv6_add_dev(). When link down, we call ipv6_mc_down(), store all multicast
addresses via mld_add_delrec(). But when link up, we don't call ipv6_mc_up()
for non-Ethernet interface to remove the addresses. This makes idev->mc_tomb
getting bigger and bigger. The call stack looks like:

addrconf_notify(NETDEV_REGISTER)
ipv6_add_dev
ipv6_dev_mc_inc(ff01::1)
ipv6_dev_mc_inc(ff02::1)
ipv6_dev_mc_inc(ff02::2)

addrconf_notify(NETDEV_UP)
addrconf_dev_config
/* Alas, we support only Ethernet autoconfiguration. */
return;

addrconf_notify(NETDEV_DOWN)
addrconf_ifdown
ipv6_mc_down
igmp6_group_dropped(ff02::2)
mld_add_delrec(ff02::2)
igmp6_group_dropped(ff02::1)
igmp6_group_dropped(ff01::1)

After investigating, I can't found a rule to disable multicast on
non-Ethernet interface. In RFC2460, the link could be Ethernet, PPP, ATM,
tunnels, etc. In IPv4, it doesn't check the dev type when calls ip_mc_up()
in inetdev_event(). Even for IPv6, we don't check the dev type and call
ipv6_add_dev(), ipv6_dev_mc_inc() after register device.

So I think it's OK to fix this memory consumer by calling ipv6_mc_up() for
non-Ethernet interface.

v2: Also check IFF_MULTICAST flag to make sure the interface supports
multicast

Reported-by: Rafał Miłecki <zajec5@gmail.com>
Tested-by: Rafał Miłecki <zajec5@gmail.com>
Fixes: 74235a25c673 ("[IPV6] addrconf: Fix IPv6 on tuntap tunnels")
Fixes: 1666d49e1d41 ("mld: do not remove mld souce list info when set link down")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: remove the old peer route if change it to a new one

When we modify the peer route and changed it to a new one, we should
remove the old route first. Before the fix:

+ ip addr add dev dummy1 2001:db8::1 peer 2001:db8::2
+ ip -6 route show dev dummy1
2001:db8::1 proto kernel metric 256 pref medium
2001:db8::2 proto kernel metric 256 pref medium
+ ip addr change dev dummy1 2001:db8::1 peer 2001:db8::3
+ ip -6 route show dev dummy1
2001:db8::1 proto kernel metric 256 pref medium
2001:db8::2 proto kernel metric 256 pref medium

After the fix:
+ ip addr change dev dummy1 2001:db8::1 peer 2001:db8::3
+ ip -6 route show dev dummy1
2001:db8::1 proto kernel metric 256 pref medium
2001:db8::3 proto kernel metric 256 pref medium

This patch depend on the previous patch "net/ipv6: need update peer route
when modify metric" to update new peer route after delete old one.

Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: need update peer route when modify metric

When we modify the route metric, the peer address's route need also
be updated. Before the fix:

+ ip addr add dev dummy1 2001:db8::1 peer 2001:db8::2 metric 60
+ ip -6 route show dev dummy1
2001:db8::1 proto kernel metric 60 pref medium
2001:db8::2 proto kernel metric 60 pref medium
+ ip addr change dev dummy1 2001:db8::1 peer 2001:db8::2 metric 61
+ ip -6 route show dev dummy1
2001:db8::1 proto kernel metric 61 pref medium
2001:db8::2 proto kernel metric 60 pref medium

After the fix:
+ ip addr change dev dummy1 2001:db8::1 peer 2001:db8::2 metric 61
+ ip -6 route show dev dummy1
2001:db8::1 proto kernel metric 61 pref medium
2001:db8::2 proto kernel metric 61 pref medium

Fixes: 8308f3ff1753 ("net/ipv6: Add support for specifying metric of connected routes")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: use configured metric when add peer route

When we add peer address with metric configured, IPv4 could set the dest
metric correctly, but IPv6 do not. e.g.

]# ip addr add 192.0.2.1 peer 192.0.2.2/32 dev eth1 metric 20
]# ip route show dev eth1
192.0.2.2 proto kernel scope link src 192.0.2.1 metric 20
]# ip addr add 2001:db8::1 peer 2001:db8::2/128 dev eth1 metric 20
]# ip -6 route show dev eth1
2001:db8::1 proto kernel metric 20 pref medium
2001:db8::2 proto kernel metric 256 pref medium

Fix this by using configured metric instead of default one.

Reported-by: Jianlin Shi <jishi@redhat.com>
Fixes: 8308f3ff1753 ("net/ipv6: Add support for specifying metric of connected routes")
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6/addrconf: fix potential NULL deref in inet6_set_link_af()

__in6_dev_get(dev) called from inet6_set_link_af() can return NULL.

The needed check has been recently removed, let's add it back.

While do_setlink() does call validate_linkmsg() :
...
err = validate_linkmsg(dev, tb); /* OK at this point */
...

It is possible that the following call happening before the
->set_link_af() removes IPv6 if MTU is less than 1280 :

if (tb[IFLA_MTU]) {
err = dev_set_mtu_ext(dev, nla_get_u32(tb[IFLA_MTU]), extack);
if (err < 0)
goto errout;
status |= DO_SETLINK_MODIFIED;
}
...

if (tb[IFLA_AF_SPEC]) {
...
err = af_ops->set_link_af(dev, af);
->inet6_set_link_af() // CRASH because idev is NULL

Please note that IPv4 is immune to the bug since inet_set_link_af() does :

struct in_device *in_dev = __in_dev_get_rcu(dev);
if (!in_dev)
return -EAFNOSUPPORT;

This problem has been mentioned in commit cf7afbfeb8ce ("rtnl: make
link af-specific updates atomic") changelog :

This method is not fail proof, while it is currently sufficient
to make set_link_af() inerrable and thus 100% atomic, the
validation function method will not be able to detect all error
scenarios in the future, there will likely always be errors
depending on states which are f.e. not protected by rtnl_mutex
and thus may change between validation and setting.

IPv6: ADDRCONF(NETDEV_CHANGE): lo: link becomes ready
general protection fault, probably for non-canonical address 0xdffffc0000000056: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000002b0-0x00000000000002b7]
CPU: 0 PID: 9698 Comm: syz-executor712 Not tainted 5.5.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:inet6_set_link_af+0x66e/0xae0 net/ipv6/addrconf.c:5733
Code: 38 d0 7f 08 84 c0 0f 85 20 03 00 00 48 8d bb b0 02 00 00 45 0f b6 64 24 04 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 1a 03 00 00 44 89 a3 b0 02 00
RSP: 0018:ffffc90005b06d40 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff86df39a6
RDX: 0000000000000056 RSI: ffffffff86df3e74 RDI: 00000000000002b0
RBP: ffffc90005b06e70 R08: ffff8880a2ac0380 R09: ffffc90005b06db0
R10: fffff52000b60dbe R11: ffffc90005b06df7 R12: 0000000000000000
R13: 0000000000000000 R14: ffff8880a1fcc424 R15: dffffc0000000000
FS: 0000000000c46880(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055f0494ca0d0 CR3: 000000009e4ac000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
do_setlink+0x2a9f/0x3720 net/core/rtnetlink.c:2754
rtnl_group_changelink net/core/rtnetlink.c:3103 [inline]
__rtnl_newlink+0xdd1/0x1790 net/core/rtnetlink.c:3257
rtnl_newlink+0x69/0xa0 net/core/rtnetlink.c:3377
rtnetlink_rcv_msg+0x45e/0xaf0 net/core/rtnetlink.c:5438
netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5456
netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
netlink_unicast+0x59e/0x7e0 net/netlink/af_netlink.c:1328
netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917
sock_sendmsg_nosec net/socket.c:652 [inline]
sock_sendmsg+0xd7/0x130 net/socket.c:672
____sys_sendmsg+0x753/0x880 net/socket.c:2343
___sys_sendmsg+0x100/0x170 net/socket.c:2397
__sys_sendmsg+0x105/0x1d0 net/socket.c:2430
__do_sys_sendmsg net/socket.c:2439 [inline]
__se_sys_sendmsg net/socket.c:2437 [inline]
__x64_sys_sendmsg+0x78/0xb0 net/socket.c:2437
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4402e9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fffd62fbcf8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004402e9
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000000000008 R09: 00000000004002c8
R10: 0000000000000005 R11: 0000000000000246 R12: 0000000000401b70
R13: 0000000000401c00 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace cfa7664b8fdcdff3 ]---
RIP: 0010:inet6_set_link_af+0x66e/0xae0 net/ipv6/addrconf.c:5733
Code: 38 d0 7f 08 84 c0 0f 85 20 03 00 00 48 8d bb b0 02 00 00 45 0f b6 64 24 04 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 1a 03 00 00 44 89 a3 b0 02 00
RSP: 0018:ffffc90005b06d40 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff86df39a6
RDX: 0000000000000056 RSI: ffffffff86df3e74 RDI: 00000000000002b0
RBP: ffffc90005b06e70 R08: ffff8880a2ac0380 R09: ffffc90005b06db0
R10: fffff52000b60dbe R11: ffffc90005b06df7 R12: 0000000000000000
R13: 0000000000000000 R14: ffff8880a1fcc424 R15: dffffc0000000000
FS: 0000000000c46880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000004 CR3: 000000009e4ac000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Fixes: 7dc2bccab0ee ("Validate required parameters in inet6_validate_link_af")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Bisected-and-reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6/addrconf: only check invalid header values when NETLINK_F_STRICT_CHK is set

In commit 4b1373de73a3 ("net: ipv6: addr: perform strict checks also for
doit handlers") we add strict check for inet6_rtm_getaddr(). But we did
the invalid header values check before checking if NETLINK_F_STRICT_CHK
is set. This may break backwards compatibility if user already set the
ifm->ifa_prefixlen, ifm->ifa_flags, ifm->ifa_scope in their netlink code.

I didn't move the nlmsg_len check because I thought it's a valid check.

Reported-by: Jianlin Shi <jishi@redhat.com>
Fixes: 4b1373de73a3 ("net: ipv6: addr: perform strict checks also for doit handlers")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>

Revert "blackhole_netdev: fix syzkaller reported issue"

This reverts commit b0818f80c8c1bc215bba276bd61c216014fab23b.

Started seeing weird behavior after this patch especially in
the IPv6 code path. Haven't root caused it, but since this was
applied to net branch, taking a precautionary measure to revert
it and look / analyze those failures

Revert this now and I'll send a better fix after analysing / fixing
the weirdness observed.

CC: Eric Dumazet <edumazet@google.com>
CC: Wei Wang <weiwan@google.com>
CC: David S. Miller <davem@davemloft.net>
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

blackhole_netdev: fix syzkaller reported issue

While invalidating the dst, we assign backhole_netdev instead of
loopback device. However, this device does not have idev pointer
and hence no ip6_ptr even if IPv6 is enabled. Possibly this has
triggered the syzbot reported crash.

The syzbot report does not have reproducer, however, this is the
only device that doesn't have matching idev created.

Crash instruction is :

static inline bool ip6_ignore_linkdown(const struct net_device *dev)
{
const struct inet6_dev *idev = __in6_dev_get(dev);

return !!idev->cnf.ignore_routes_with_linkdown; <= crash
}

Also ipv6 always assumes presence of idev and never checks for it
being NULL (as does the above referenced code). So adding a idev
for the blackhole_netdev to avoid this class of crashes in the future.

Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: Handle missing host route in __ipv6_ifa_notify

Rajendra reported a kernel panic when a link was taken down:

[ 6870.263084] BUG: unable to handle kernel NULL pointer dereference at 00000000000000a8
[ 6870.271856] IP: [<ffffffff8efc5764>] __ipv6_ifa_notify+0x154/0x290

<snip>

[ 6870.570501] Call Trace:
[ 6870.573238] [<ffffffff8efc58c6>] ? ipv6_ifa_notify+0x26/0x40
[ 6870.579665] [<ffffffff8efc98ec>] ? addrconf_dad_completed+0x4c/0x2c0
[ 6870.586869] [<ffffffff8efe70c6>] ? ipv6_dev_mc_inc+0x196/0x260
[ 6870.593491] [<ffffffff8efc9c6a>] ? addrconf_dad_work+0x10a/0x430
[ 6870.600305] [<ffffffff8f01ade4>] ? __switch_to_asm+0x34/0x70
[ 6870.606732] [<ffffffff8ea93a7a>] ? process_one_work+0x18a/0x430
[ 6870.613449] [<ffffffff8ea93d6d>] ? worker_thread+0x4d/0x490
[ 6870.619778] [<ffffffff8ea93d20>] ? process_one_work+0x430/0x430
[ 6870.626495] [<ffffffff8ea99dd9>] ? kthread+0xd9/0xf0
[ 6870.632145] [<ffffffff8f01ade4>] ? __switch_to_asm+0x34/0x70
[ 6870.638573] [<ffffffff8ea99d00>] ? kthread_park+0x60/0x60
[ 6870.644707] [<ffffffff8f01ae77>] ? ret_from_fork+0x57/0x70
[ 6870.650936] Code: 31 c0 31 d2 41 b9 20 00 08 02 b9 09 00 00 0

addrconf_dad_work is kicked to be scheduled when a device is brought
up. There is a race between addrcond_dad_work getting scheduled and
taking the rtnl lock and a process taking the link down (under rtnl).
The latter removes the host route from the inet6_addr as part of
addrconf_ifdown which is run for NETDEV_DOWN. The former attempts
to use the host route in __ipv6_ifa_notify. If the down event removes
the host route due to the race to the rtnl, then the BUG listed above
occurs.

Since the DAD sequence can not be aborted, add a check for the missing
host route in __ipv6_ifa_notify. The only way this should happen is due
to the previously mentioned race. The host route is created when the
address is added to an interface; it is only removed on a down event
where the address is kept. Add a warning if the host route is missing
AND the device is up; this is a situation that should never happen.

Fixes: f1705ec197e7 ("net: ipv6: Make address flushing on ifdown optional")
Reported-by: Rajendra Dendukuri <rajendra.dendukuri@broadcom.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Revert "ipv6: Handle race in addrconf_dad_work"

This reverts commit a3ce2a21bb8969ae27917281244fa91bf5f286d7.

Eric reported tests failings with commit. After digging into it,
the bottom line is that the DAD sequence is not to be messed with.
There are too many cases that are expected to proceed regardless
of whether a device is up.

Revert the patch and I will send a different solution for the
problem Rajendra reported.

Signed-off-by: David Ahern <dsahern@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: Handle race in addrconf_dad_work

Rajendra reported a kernel panic when a link was taken down:

[ 6870.263084] BUG: unable to handle kernel NULL pointer dereference at 00000000000000a8
[ 6870.271856] IP: [<ffffffff8efc5764>] __ipv6_ifa_notify+0x154/0x290

<snip>

[ 6870.570501] Call Trace:
[ 6870.573238] [<ffffffff8efc58c6>] ? ipv6_ifa_notify+0x26/0x40
[ 6870.579665] [<ffffffff8efc98ec>] ? addrconf_dad_completed+0x4c/0x2c0
[ 6870.586869] [<ffffffff8efe70c6>] ? ipv6_dev_mc_inc+0x196/0x260
[ 6870.593491] [<ffffffff8efc9c6a>] ? addrconf_dad_work+0x10a/0x430
[ 6870.600305] [<ffffffff8f01ade4>] ? __switch_to_asm+0x34/0x70
[ 6870.606732] [<ffffffff8ea93a7a>] ? process_one_work+0x18a/0x430
[ 6870.613449] [<ffffffff8ea93d6d>] ? worker_thread+0x4d/0x490
[ 6870.619778] [<ffffffff8ea93d20>] ? process_one_work+0x430/0x430
[ 6870.626495] [<ffffffff8ea99dd9>] ? kthread+0xd9/0xf0
[ 6870.632145] [<ffffffff8f01ade4>] ? __switch_to_asm+0x34/0x70
[ 6870.638573] [<ffffffff8ea99d00>] ? kthread_park+0x60/0x60
[ 6870.644707] [<ffffffff8f01ae77>] ? ret_from_fork+0x57/0x70
[ 6870.650936] Code: 31 c0 31 d2 41 b9 20 00 08 02 b9 09 00 00 0

addrconf_dad_work is kicked to be scheduled when a device is brought
up. There is a race between addrcond_dad_work getting scheduled and
taking the rtnl lock and a process taking the link down (under rtnl).
The latter removes the host route from the inet6_addr as part of
addrconf_ifdown which is run for NETDEV_DOWN. The former attempts
to use the host route in ipv6_ifa_notify. If the down event removes
the host route due to the race to the rtnl, then the BUG listed above
occurs.

This scenario does not occur when the ipv6 address is not kept
(net.ipv6.conf.all.keep_addr_on_down = 0) as addrconf_ifdown sets the
state of the ifp to DEAD. Handle when the addresses are kept by checking
IF_READY which is reset by addrconf_ifdown.

The 'dead' flag for an inet6_addr is set only under rtnl, in
addrconf_ifdown and it means the device is getting removed (or IPv6 is
disabled). The interesting cases for changing the idev flag are
addrconf_notify (NETDEV_UP and NETDEV_CHANGE) and addrconf_ifdown
(reset the flag). The former does not have the idev lock - only rtnl;
the latter has both. Based on that the existing dead + IF_READY check
can be moved to right after the rtnl_lock in addrconf_dad_work.

Fixes: f1705ec197e7 ("net: ipv6: Make address flushing on ifdown optional")
Reported-by: Rajendra Dendukuri <rajendra.dendukuri@broadcom.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: minor code reorg in inet6_fill_ifla6_attrs()

Just put related code together to ease code reading: the memcpy() is
related to the nla_reserve().

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: propagate ipv6_add_dev's error returns out of ipv6_find_idev

Currently, ipv6_find_idev returns NULL when ipv6_add_dev fails,
ignoring the specific error value. This results in addrconf_add_dev
returning ENOBUFS in all cases, which is unfortunate in cases such as:

# ip link add dummyX type dummy
# ip link set dummyX mtu 1200 up
# ip addr add 2000::/64 dev dummyX
RTNETLINK answers: No buffer space available

Commit a317a2f19da7 ("ipv6: fail early when creating netdev named all
or default") introduced error returns in ipv6_add_dev. Before that,
that function would simply return NULL for all failures.

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6/addrconf: allow adding multicast addr if IFA_F_MCAUTOJOIN is set

In commit 93a714d6b53d ("multicast: Extend ip address command to enable
multicast group join/leave on") we added a new flag IFA_F_MCAUTOJOIN
to make user able to add multicast address on ethernet interface.

This works for IPv4, but not for IPv6. See the inet6_addr_add code.

static int inet6_addr_add()
{
...
if (cfg->ifa_flags & IFA_F_MCAUTOJOIN) {
ipv6_mc_config(net->ipv6.mc_autojoin_sk, true...)
}

ifp = ipv6_add_addr(idev, cfg, true, extack); <- always fail with maddr
if (!IS_ERR(ifp)) {
...
} else if (cfg->ifa_flags & IFA_F_MCAUTOJOIN) {
ipv6_mc_config(net->ipv6.mc_autojoin_sk, false...)
}
}

But in ipv6_add_addr() it will check the address type and reject multicast
address directly. So this feature is never worked for IPv6.

We should not remove the multicast address check totally in ipv6_add_addr(),
but could accept multicast address only when IFA_F_MCAUTOJOIN flag supplied.

v2: update commit description

Fixes: 93a714d6b53d ("multicast: Extend ip address command to enable multicast group join/leave on")
Reported-by: Jianlin Shi <jishi@redhat.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

proc/sysctl: add shared variables for range check

In the sysctl code the proc_dointvec_minmax() function is often used to
validate the user supplied value between an allowed range. This
function uses the extra1 and extra2 members from struct ctl_table as
minimum and maximum allowed value.

On sysctl handler declaration, in every source file there are some
readonly variables containing just an integer which address is assigned
to the extra1 and extra2 members, so the sysctl range is enforced.

The special values 0, 1 and INT_MAX are very often used as range
boundary, leading duplication of variables like zero=0, one=1,
int_max=INT_MAX in different source files:

$ git grep -E '\.extra[12].*&(zero|one|int_max)' |wc -l
248

Add a const int array containing the most commonly used values, some
macros to refer more easily to the correct array member, and use them
instead of creating a local one for every object file.

This is the bloat-o-meter output comparing the old and new binary
compiled with the default Fedora config:

# scripts/bloat-o-meter -d vmlinux.o.old vmlinux.o
add/remove: 2/2 grow/shrink: 0/2 up/down: 24/-188 (-164)
Data old new delta
sysctl_vals - 12 +12
__kstrtab_sysctl_vals - 12 +12
max 14 10 -4
int_max 16 - -16
one 68 - -68
zero 128 28 -100
Total: Before=20583249, After=20583085, chg -0.00%

[mcroce@redhat.com: tipc: remove two unused variables]
Link: http://lkml.kernel.org/r/20190530091952.4108-1-mcroce@redhat.com
[akpm@linux-foundation.org: fix net/ipv6/sysctl_net_ipv6.c]
[arnd@arndb.de: proc/sysctl: make firmware loader table conditional]
Link: http://lkml.kernel.org/r/20190617130014.1713870-1-arnd@arndb.de
[akpm@linux-foundation.org: fix fs/eventpoll.c]
Link: http://lkml.kernel.org/r/20190430180111.10688-1-mcroce@redhat.com
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Aaron Tomlin <atomlin@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ipv6: Plumb support for nexthop object in a fib6_info

Add struct nexthop and nh_list list_head to fib6_info. nh_list is the
fib6_info side of the nexthop <-> fib_info relationship. Since a fib6_info
referencing a nexthop object can not have 'sibling' entries (the old way
of doing multipath routes), the nh_list is a union with fib6_siblings.

Add f6i_list list_head to 'struct nexthop' to track fib6_info entries
using a nexthop instance. Update __remove_nexthop_fib to walk f6_list
and delete fib entries using the nexthop.

Add a few nexthop helpers for use when a nexthop is added to fib6_info:
- nexthop_fib6_nh - return first fib6_nh in a nexthop object
- fib6_info_nh_dev moved to nexthop.h and updated to use nexthop_fib6_nh
if the fib6_info references a nexthop object
- nexthop_path_fib6_result - similar to ipv4, select a path within a
multipath nexthop object. If the nexthop is a blackhole, set
fib6_result type to RTN_BLACKHOLE, and set the REJECT flag

Update the fib6_info references to check for nh and take a different path
as needed:
- rt6_qualify_for_ecmp - if a fib entry uses a nexthop object it can NOT
be coalesced with other fib entries into a multipath route
- rt6_duplicate_nexthop - use nexthop_cmp if either fib6_info references
a nexthop
- addrconf (host routes), RA's and info entries (anything configured via
ndisc) does not use nexthop objects
- fib6_info_destroy_rcu - put reference to nexthop object
- fib6_purge_rt - drop fib6_info from f6i_list
- fib6_select_path - update to use the new nexthop_path_fib6_result when
fib entry uses a nexthop object
- rt6_device_match - update to catch use of nexthop object as a blackhole
and set fib6_type and flags.
- ip6_route_info_create - don't add space for fib6_nh if fib entry is
going to reference a nexthop object, take a reference to nexthop object,
disallow use of source routing
- rt6_nlmsg_size - add space for RTA_NH_ID
- add rt6_fill_node_nexthop to add nexthop data on a dump

As with ipv4, most of the changes push existing code into the else branch
of whether the fib entry uses a nexthop object.

Update the nexthop code to walk f6i_list on a nexthop deleted to remove
fib entries referencing it.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: use new in_dev_ifa iterators

Use in_dev_for_each_ifa_rcu/rtnl instead.
This prevents sparse warnings once proper __rcu annotations are added.

Signed-off-by: Florian Westphal <fw@strlen.de>

t di# Last commands done (6 commands done):

Signed-off-by: David S. Miller <davem@davemloft.net>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ipv6: Make fib6_nh optional at the end of fib6_info

Move fib6_nh to the end of fib6_info and make it an array of
size 0. Pass a flag to fib6_info_alloc indicating if the
allocation needs to add space for a fib6_nh.

The current code path always has a fib6_nh allocated with a
fib6_info; with nexthop objects they will be separate.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: Move pcpu cached routes to fib6_nh

rt6_info are specific instances of a fib entry and are tied to a
device and gateway - ie., a nexthop. Before nexthop objects, IPv6 fib
entries have separate fib6_info for each nexthop in a multipath route,
so the location of the pcpu cache in the fib6_info struct worked.
However, with nexthop objects a fib6_info can point to a set of nexthops
(yet another alignment of ipv6 with ipv4). Accordingly, the pcpu
cache needs to be moved to the fib6_nh struct so the cached entries
are local to the nexthop specification used to create the rt6_info.

Initialization and free of the pcpu entries moved to fib6_nh_init and
fib6_nh_release.

Change in location only, from fib6_info down to fib6_nh; no other
functional change intended.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Validate required parameters in inet6_validate_link_af

inet6_set_link_af requires that at least one of IFLA_INET6_TOKEN or
IFLA_INET6_ADDR_GET_MODE is passed. If none of them is passed, it
returns -EINVAL, which may cause do_setlink() to fail in the middle of
processing other commands and give the following warning message:

A link change request failed with some changes committed already.
Interface eth0 may have been left with an inconsistent configuration,
please check.

Check the presence of at least one of them in inet6_validate_link_af to
detect invalid parameters at an early stage, before do_setlink does
anything. Also validate the address generation mode at an early stage.

Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

netlink: make validation more configurable for future strictness

We currently have two levels of strict validation:

1) liberal (default)
- undefined (type >= max) & NLA_UNSPEC attributes accepted
- attribute length >= expected accepted
- garbage at end of message accepted
2) strict (opt-in)
- NLA_UNSPEC attributes accepted
- attribute length >= expected accepted

Split out parsing strictness into four different options:
* TRAILING - check that there's no trailing data after parsing
attributes (in message or nested)
* MAXTYPE - reject attrs > max known type
* UNSPEC - reject attributes with NLA_UNSPEC policy entries
* STRICT_ATTRS - strictly validate attribute size

The default for future things should be *everything*.
The current *_strict() is a combination of TRAILING and MAXTYPE,
and is renamed to _deprecated_strict().
The current regular parsing has none of this, and is renamed to
*_parse_deprecated().

Additionally it allows us to selectively set one of the new flags
even on old policies. Notably, the UNSPEC flag could be useful in
this case, since it can be arranged (by filling in the policy) to
not be an incompatible userspace ABI change, but would then going
forward prevent forgetting attribute entries. Similar can apply
to the POLICY flag.

We end up with the following renames:
* nla_parse -> nla_parse_deprecated
* nla_parse_strict -> nla_parse_deprecated_strict
* nlmsg_parse -> nlmsg_parse_deprecated
* nlmsg_parse_strict -> nlmsg_parse_deprecated_strict
* nla_parse_nested -> nla_parse_nested_deprecated
* nla_validate_nested -> nla_validate_nested_deprecated

Using spatch, of course:
@@
expression TB, MAX, HEAD, LEN, POL, EXT;
@@
-nla_parse(TB, MAX, HEAD, LEN, POL, EXT)
+nla_parse_deprecated(TB, MAX, HEAD, LEN, POL, EXT)

@@
expression NLH, HDRLEN, TB, MAX, POL, EXT;
@@
-nlmsg_parse(NLH, HDRLEN, TB, MAX, POL, EXT)
+nlmsg_parse_deprecated(NLH, HDRLEN, TB, MAX, POL, EXT)

@@
expression NLH, HDRLEN, TB, MAX, POL, EXT;
@@
-nlmsg_parse_strict(NLH, HDRLEN, TB, MAX, POL, EXT)
+nlmsg_parse_deprecated_strict(NLH, HDRLEN, TB, MAX, POL, EXT)

@@
expression TB, MAX, NLA, POL, EXT;
@@
-nla_parse_nested(TB, MAX, NLA, POL, EXT)
+nla_parse_nested_deprecated(TB, MAX, NLA, POL, EXT)

@@
expression START, MAX, POL, EXT;
@@
-nla_validate_nested(START, MAX, POL, EXT)
+nla_validate_nested_deprecated(START, MAX, POL, EXT)

@@
expression NLH, HDRLEN, MAX, POL, EXT;
@@
-nlmsg_validate(NLH, HDRLEN, MAX, POL, EXT)
+nlmsg_validate_deprecated(NLH, HDRLEN, MAX, POL, EXT)

For this patch, don't actually add the strict, non-renamed versions
yet so that it breaks compile if I get it wrong.

Also, while at it, make nla_validate and nla_parse go down to a
common __nla_validate_parse() function to avoid code duplication.

Ultimately, this allows us to have very strict validation for every
new caller of nla_parse()/nlmsg_parse() etc as re-introduced in the
next patch, while existing things will continue to work as is.

In effect then, this adds fully strict validation for any new command.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

netlink: make nla_nest_start() add NLA_F_NESTED flag

Even if the NLA_F_NESTED flag was introduced more than 11 years ago, most
netlink based interfaces (including recently added ones) are still not
setting it in kernel generated messages. Without the flag, message parsers
not aware of attribute semantics (e.g. wireshark dissector or libmnl's
mnl_nlmsg_fprintf()) cannot recognize nested attributes and won't display
the structure of their contents.

Unfortunately we cannot just add the flag everywhere as there may be
userspace applications which check nlattr::nla_type directly rather than
through a helper masking out the flags. Therefore the patch renames
nla_nest_start() to nla_nest_start_noflag() and introduces nla_nest_start()
as a wrapper adding NLA_F_NESTED. The calls which add NLA_F_NESTED manually
are rewritten to use nla_nest_start().

Except for changes in include/net/netlink.h, the patch was generated using
this semantic patch:

@@ expression E1, E2; @@
-nla_nest_start(E1, E2)
+nla_nest_start_noflag(E1, E2)

@@ expression E1, E2; @@
-nla_nest_start_noflag(E1, E2 | NLA_F_NESTED)
+nla_nest_start(E1, E2)

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Replace nhc_has_gw with nhc_gw_family

Allow the gateway in a fib_nh_common to be from a different address
family than the outer fib{6}_nh. To that end, replace nhc_has_gw with
nhc_gw_family and update users of nhc_has_gw to check nhc_gw_family.
Now nhc_family is used to know if the nh_common is part of a fib_nh
or fib6_nh (used for container_of to get to route family specific data),
and nhc_gw_family represents the address family for the gateway.

Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: Rename fib6_nh entries

Rename fib6_nh entries that will be moved to a fib_nh_common struct.
Specifically, the device, gateway, flags, and lwtstate are common
with all nexthop definitions. In some places new temporary variables
are declared or local variables renamed to maintain line lengths.

Rename only; no functional change intended.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: Move gateway checks to a fib6_nh setting

The gateway setting is not per fib6_info entry but per-fib6_nh. Add a new
fib_nh_has_gw flag to fib6_nh and convert references to RTF_GATEWAY to
the new flag. For IPv6 address the flag is cheaper than checking that
nh_gw is non-0 like IPv4 does.

While this increases fib6_nh by 8-bytes, the effective allocation size of
a fib6_info is unchanged. The 8 bytes is recovered later with a
fib_nh_common change.

Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ignore sysctl_devconf_inherit_init_net without SYSCTL

When CONFIG_SYSCTL is turned off, we get a link failure for
the newly introduced tuning knob.

net/ipv6/addrconf.o: In function `addrconf_init_net':
addrconf.c:(.text+0x31dc): undefined reference to `sysctl_devconf_inherit_init_net'

Add an IS_ENABLED() check to fall back to the default behavior
(sysctl_devconf_inherit_init_net=0) here.

Fixes: 856c395cfa63 ("net: introduce a knob to control whether to inherit devconf config")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Christian Brauner <christian@brauner.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: fix IPv6 prefix route residue

Follow those steps:
# ip addr add 2001:123::1/32 dev eth0
# ip addr add 2001:123:456::2/64 dev eth0
# ip addr del 2001:123::1/32 dev eth0
# ip addr del 2001:123:456::2/64 dev eth0
and then prefix route of 2001:123::1/32 will still exist.

This is because ipv6_prefix_equal in check_cleanup_prefix_route
func does not check whether two IPv6 addresses have the same
prefix length. If the prefix of one address starts with another
shorter address prefix, even though their prefix lengths are
different, the return value of ipv6_prefix_equal is true.

Here I add a check of whether two addresses have the same prefix
to decide whether their prefixes are equal.

Fixes: 5b84efecb7d9 ("ipv6 addrconf: don't cleanup prefix route for IFA_F_NOPREFIXROUTE")
Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Reported-by: Wenhao Zhang <zhangwenhao8@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: lower the level of "link is not ready" messages

This message gets logged far too often for how interesting is it.

Most distributions nowadays configure NetworkManager to use randomly
generated MAC addresses for Wi-Fi network scans. The interfaces end up
being periodically brought down for the address change. When they're
subsequently brought back up, the message is logged, eventually flooding
the log.

Perhaps the message is not all that helpful: it seems to be more
interesting to hear when the addrconf actually start, not when it does
not. Let's lower its level.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Acked-By: Thomas Haller <thaller@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: don't return positive numbers when nothing was dumped

in6_dump_addrs() returns a positive 1 if there was nothing to dump.
This return value can not be passed as return from inet6_dump_addr()
as is, because it will confuse rtnetlink, resulting in NLMSG_DONE
never getting set:

$ ip addr list dev lo
EOF on netlink
Dump terminated

v2: flip condition to avoid a new goto (DaveA)

Fixes: 7c1e8a3817c5 ("netlink: fixup regression in RTM_GETADDR")
Reported-by: Brendan Galloway <brendan.galloway@netronome.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Tested-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: introduce a knob to control whether to inherit devconf config

There have been many people complaining about the inconsistent
behaviors of IPv4 and IPv6 devconf when creating new network
namespaces. Currently, for IPv4, we inherit all current settings
from init_net, but for IPv6 we reset all setting to default.

This patch introduces a new /proc file
/proc/sys/net/core/devconf_inherit_init_net to control the
behavior of whether to inhert sysctl current settings from init_net.
This file itself is only available in init_net.

As demonstrated below:

Initial setup in init_net:
# cat /proc/sys/net/ipv4/conf/all/rp_filter
2
# cat /proc/sys/net/ipv6/conf/all/accept_dad
1

Default value 0 (current behavior):
# ip netns del test
# ip netns add test
# ip netns exec test cat /proc/sys/net/ipv4/conf/all/rp_filter
2
# ip netns exec test cat /proc/sys/net/ipv6/conf/all/accept_dad
0

Set to 1 (inherit from init_net):
# echo 1 > /proc/sys/net/core/devconf_inherit_init_net
# ip netns del test
# ip netns add test
# ip netns exec test cat /proc/sys/net/ipv4/conf/all/rp_filter
2
# ip netns exec test cat /proc/sys/net/ipv6/conf/all/accept_dad
1

Set to 2 (reset to default):
# echo 2 > /proc/sys/net/core/devconf_inherit_init_net
# ip netns del test
# ip netns add test
# ip netns exec test cat /proc/sys/net/ipv4/conf/all/rp_filter
0
# ip netns exec test cat /proc/sys/net/ipv6/conf/all/accept_dad
0

Set to a value out of range (invalid):
# echo 3 > /proc/sys/net/core/devconf_inherit_init_net
-bash: echo: write error: Invalid argument
# echo -1 > /proc/sys/net/core/devconf_inherit_init_net
-bash: echo: write error: Invalid argument

Reported-by: Zhu Yanjun <Yanjun.Zhu@windriver.com>
Reported-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipv6: netconf: perform strict checks also for doit handlers

Make RTM_GETNETCONF's doit handler use strict checks when
NETLINK_F_STRICT_CHK is set.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipv6: addr: perform strict checks also for doit handlers

Make RTM_GETADDR's doit handler use strict checks when
NETLINK_F_STRICT_CHK is set.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

netlink: fixup regression in RTM_GETADDR

This commit fixes a regression in AF_INET/RTM_GETADDR and
AF_INET6/RTM_GETADDR.

Before this commit, the kernel would stop dumping addresses once the first
skb was full and end the stream with NLMSG_DONE(-EMSGSIZE). The error
shouldn't be sent back to netlink_dump so the callback is kept alive. The
userspace is expected to call back with a new empty skb.

Changes from V1:
- The error is not handled in netlink_dump anymore but rather in
inet_dump_ifaddr and inet6_dump_addr directly as suggested by
David Ahern.

Fixes: d7e38611b81e ("net/ipv4: Put target net when address dump fails due to bad attributes")
Fixes: 242afaa6968c ("net/ipv6: Put target net when address dump fails due to bad attributes")

Cc: David Ahern <dsahern@gmail.com>
Cc: "David S . Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Signed-off-by: Arthur Gautier <baloo@gandi.net>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Fix a test against 'ipv6_find_idev()' return value

'ipv6_find_idev()' returns NULL on error, not an error pointer.
Update the test accordingly and return -ENOBUFS, as already done in
'addrconf_add_dev()', if NULL is returned.

Fixes: ("ipv6: allow userspace to add IFA_F_OPTIMISTIC addresses")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: core: dev: Add extack argument to dev_open()

In order to pass extack together with NETDEV_PRE_UP notifications, it's
necessary to route the extack to __dev_open() from diverse (possibly
indirect) callers. One prominent API through which the notification is
invoked is dev_open().

Therefore extend dev_open() with and extra extack argument and update
all users. Most of the calls end up just encoding NULL, but bond and
team drivers have the extack readily available.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: re-do dad when interface has IFF_NOARP flag change

When we add a new IPv6 address, we should also join corresponding solicited-node
multicast address, unless the interface has IFF_NOARP flag, as function
addrconf_join_solict() did. But if we remove IFF_NOARP flag later, we do
not do dad and add the mcast address. So we will drop corresponding neighbour
discovery message that came from other nodes.

A typical example is after creating a ipvlan with mode l3, setting up an ipv6
address and changing the mode to l2. Then we will not be able to ping this
address as the interface doesn't join related solicited-node mcast address.

Fix it by re-doing dad when interface changed IFF_NOARP flag. Then we will add
corresponding mcast group and check if there is a duplicate address on the
network.

Reported-by: Jianlin Shi <jishi@redhat.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/{ipv4,ipv6}: Do not put target net if input nsid is invalid

The cleanup path will put the target net when netnsid is set. So we must
reset netnsid if the input is invalid.

Fixes: d7e38611b81e ("net/ipv4: Put target net when address dump fails due to bad attributes")
Fixes: 242afaa6968c ("net/ipv6: Put target net when address dump fails due to bad attributes")
Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Put target net when address dump fails due to bad attributes

If tgt_net is set based on IFA_TARGET_NETNSID attribute in the dump
request, make sure all error paths call put_net.

Fixes: 6371a71f3a3b ("net/ipv6: Add support for dumping addresses for a specific device")
Fixes: ed6eff11790a ("net/ipv6: Update inet6_dump_addr for strict data checking")
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Add support for dumping addresses for a specific device

If an RTM_GETADDR dump request has ifa_index set in the ifaddrmsg
header, then return only the addresses for that device.

Since inet6_dump_addr is reused for multicast and anycast addresses,
this adds support for device specfic dumps of RTM_GETMULTICAST and
RTM_GETANYCAST as well.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Remove ip_idx arg to in6_dump_addrs

ip_idx is always 0 going into in6_dump_addrs; it is passed as a pointer
to save the last good index into cb. Since cb is already argument to
in6_dump_addrs, just save the value there.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Fix index counter for unicast addresses in in6_dump_addrs

The loop wants to skip previously dumped addresses, so loops until
current index >= saved index. If the message fills it wants to save
the index for the next address to dump - ie., the one that did not
fit in the current message.

Currently, it is incrementing the index counter before comparing to the
saved index, and then the saved index is off by 1 - it assumes the
current address is going to fit in the message.

Change the index handling to increment only after a succesful dump.

Fixes: 502a2ffd7376a ("ipv6: convert idev_list to list macros")
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Update netconf dump handlers for strict data checking

Update inet_netconf_dump_devconf, inet6_netconf_dump_devconf, and
mpls_netconf_dump_devconf for strict data checking. If the flag is set,
the dump request is expected to have an netconfmsg struct as the header.
The struct only has the family member and no attributes can be appended.

Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Christian Brauner <christian@brauner.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

rtnetlink: Update inet6_dump_ifinfo for strict data checking

Update inet6_dump_ifinfo for strict data checking. If the flag is
set, the dump request is expected to have an ifinfomsg struct as
the header. All elements of the struct are expected to be 0 and no
attributes can be appended.

Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Christian Brauner <christian@brauner.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Update inet6_dump_addr for strict data checking

Update inet6_dump_addr for strict data checking. If the flag is set, the
dump request is expected to have an ifaddrmsg struct as the header
potentially followed by one or more attributes. Any data passed in the
header or as an attribute is taken as a request to influence the data
returned. Only values suppored by the dump handler are allowed to be
non-0 or set in the request. At the moment only the IFA_TARGET_NETNSID
attribute is supported. Follow on patches can add support for other fields
(e.g., honor ifa_index and only return data for the given device index).

Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Christian Brauner <christian@brauner.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Refactor address dump to push inet6_fill_args to in6_dump_addrs

Pull the inet6_fill_args arg up to in6_dump_addrs and move netnsid
into it.

Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Christian Brauner <christian@brauner.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Add extack to nlmsg_parse

Make sure extack is passed to nlmsg_parse where easy to do so.
Most of these are dump handlers and leveraging the extack in
the netlink_callback.

Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Christian Brauner <christian@brauner.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Display all addresses in output of /proc/net/if_inet6

The backend handling for /proc/net/if_inet6 in addrconf.c doesn't properly
handle starting/stopping the iteration. The problem is that at some point
during the iteration, an overflow is detected and the process is
subsequently stopped. The item being shown via seq_printf() when the
overflow occurs is not actually shown, though. When start() is
subsequently called to resume iterating, it returns the next item, and
thus the item that was being processed when the overflow occurred never
gets printed.

Alter the meaning of the private data member "offset". Currently, when it
is not 0 (which only happens at the very beginning), "offset" represents
the next hlist item to be printed. After this change, "offset" always
represents the current item.

This is also consistent with the private data member "bucket", which
represents the current bucket, and also the use of "pos" as defined in
seq_file.txt:
The pos passed to start() will always be either zero, or the most
recent pos used in the previous session.

Signed-off-by: Jeff Barnhill <0xeffeff@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: Allow the l3mdev to be a loopback

There is no way currently for an IPv6 client connect using a loopback
address in a VRF, whereas for IPv4 the loopback address can be added:

$ sudo ip addr add dev vrfred 127.0.0.1/8
$ sudo ip -6 addr add ::1/128 dev vrfred
RTNETLINK answers: Cannot assign requested address

So allow ::1 to be configured on an L3 master device. In order for
this to be usable ip_route_output_flags needs to not consider ::1 to
be a link scope address (since oif == l3mdev and so it would be
dropped), and ipv6_rcv needs to consider the l3mdev to be a loopback
device so that it doesn't drop the packets.

Signed-off-by: Robert Shearman <rshearma@vyatta.att-mail.com>
Signed-off-by: Mike Manning <mmanning@vyatta.att-mail.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: add inet6_fill_args

inet6_fill_if{addr,mcaddr, acaddr}() already took 6 arguments which
meant the 7th argument would need to be pushed onto the stack on x86.
Add a new struct inet6_fill_args which holds common information passed
to inet6_fill_if{addr,mcaddr, acaddr}() and shortens the functions to
three pointer arguments.

Signed-off-by: Christian Brauner <christian@brauner.io>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: enable IFA_TARGET_NETNSID for RTM_GETADDR

- Backwards Compatibility:
If userspace wants to determine whether ipv6 RTM_GETADDR requests
support the new IFA_TARGET_NETNSID property it should verify that the
reply includes the IFA_TARGET_NETNSID property. If it does not
userspace should assume that IFA_TARGET_NETNSID is not supported for
ipv6 RTM_GETADDR requests on this kernel.
- From what I gather from current userspace tools that make use of
RTM_GETADDR requests some of them pass down struct ifinfomsg when they
should actually pass down struct ifaddrmsg. To not break existing
tools that pass down the wrong struct we will do the same as for
RTM_GETLINK | NLM_F_DUMP requests and not error out when the
nlmsg_parse() fails.

- Security:
Callers must have CAP_NET_ADMIN in the owning user namespace of the
target network namespace.

Signed-off-by: Christian Brauner <christian@brauner.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

addrconf: reduce unnecessary atomic allocations

All the 3 callers of addrconf_add_mroute() assert RTNL
lock, they don't take any additional lock either, so
it is safe to convert it to GFP_KERNEL.

Same for sit_add_v4_addrs().

Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: use fib6_info_hold_safe() when necessary

In the code path where only rcu read lock is held, e.g. in the route
lookup code path, it is not safe to directly call fib6_info_hold()
because the fib6_info may already have been deleted but still exists
in the rcu grace period. Holding reference to it could cause double
free and crash the kernel.

This patch adds a new function fib6_info_hold_safe() and replace
fib6_info_hold() in all necessary places.

Syzbot reported 3 crash traces because of this. One of them is:
8021q: adding VLAN 0 to HW filter on device team0
IPv6: ADDRCONF(NETDEV_CHANGE): team0: link becomes ready
dst_release: dst:(____ptrval____) refcnt:-1
dst_release: dst:(____ptrval____) refcnt:-2
WARNING: CPU: 1 PID: 4845 at include/net/dst.h:239 dst_hold include/net/dst.h:239 [inline]
WARNING: CPU: 1 PID: 4845 at include/net/dst.h:239 ip6_setup_cork+0xd66/0x1830 net/ipv6/ip6_output.c:1204
dst_release: dst:(____ptrval____) refcnt:-1
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 4845 Comm: syz-executor493 Not tainted 4.18.0-rc3+ #10
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
panic+0x238/0x4e7 kernel/panic.c:184
dst_release: dst:(____ptrval____) refcnt:-2
dst_release: dst:(____ptrval____) refcnt:-3
__warn.cold.8+0x163/0x1ba kernel/panic.c:536
dst_release: dst:(____ptrval____) refcnt:-4
report_bug+0x252/0x2d0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:178 [inline]
do_error_trap+0x1fc/0x4d0 arch/x86/kernel/traps.c:296
dst_release: dst:(____ptrval____) refcnt:-5
do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992
RIP: 0010:dst_hold include/net/dst.h:239 [inline]
RIP: 0010:ip6_setup_cork+0xd66/0x1830 net/ipv6/ip6_output.c:1204
Code: c1 ed 03 89 9d 18 ff ff ff 48 b8 00 00 00 00 00 fc ff df 41 c6 44 05 00 f8 e9 2d 01 00 00 4c 8b a5 c8 fe ff ff e8 1a f6 e6 fa <0f> 0b e9 6a fc ff ff e8 0e f6 e6 fa 48 8b 85 d0 fe ff ff 48 8d 78
RSP: 0018:ffff8801a8fcf178 EFLAGS: 00010293
RAX: ffff8801a8eba5c0 RBX: 0000000000000000 RCX: ffffffff869511e6
RDX: 0000000000000000 RSI: ffffffff869515b6 RDI: 0000000000000005
RBP: ffff8801a8fcf2c8 R08: ffff8801a8eba5c0 R09: ffffed0035ac8338
R10: ffffed0035ac8338 R11: ffff8801ad6419c3 R12: ffff8801a8fcf720
R13: ffff8801a8fcf6a0 R14: ffff8801ad6419c0 R15: ffff8801ad641980
ip6_make_skb+0x2c8/0x600 net/ipv6/ip6_output.c:1768
udpv6_sendmsg+0x2c90/0x35f0 net/ipv6/udp.c:1376
inet_sendmsg+0x1a1/0x690 net/ipv4/af_inet.c:798
sock_sendmsg_nosec net/socket.c:641 [inline]
sock_sendmsg+0xd5/0x120 net/socket.c:651
___sys_sendmsg+0x51d/0x930 net/socket.c:2125
__sys_sendmmsg+0x240/0x6f0 net/socket.c:2220
__do_sys_sendmmsg net/socket.c:2249 [inline]
__se_sys_sendmmsg net/socket.c:2246 [inline]
__x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2246
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x446ba9
Code: e8 cc bb 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fb39a469da8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00000000006dcc54 RCX: 0000000000446ba9
RDX: 00000000000000b8 RSI: 0000000020001b00 RDI: 0000000000000003
RBP: 00000000006dcc50 R08: 00007fb39a46a700 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 45c828efc7a64843
R13: e6eeb815b9d8a477 R14: 5068caf6f713c6fc R15: 0000000000000001
Dumping ftrace buffer:
(ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..

Fixes: 93531c674315 ("net/ipv6: separate handling of FIB entries from dst based routes")
Reported-by: syzbot+902e2a1bcd4f7808cef5@syzkaller.appspotmail.com
Reported-by: syzbot+8ae62d67f647abeeceb9@syzkaller.appspotmail.com
Reported-by: syzbot+3f08feb14086930677d0@syzkaller.appspotmail.com
Signed-off-by: Wei Wang <weiwan@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: propagate net.ipv6.conf.all.addr_gen_mode to devices

This aligns the addr_gen_mode sysctl with the expected behavior of the
"all" variant.

Fixes: d35a00b8e33d ("net/ipv6: allow sysctl to change link-local address generation mode")
Suggested-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: reserve room for IFLA_INET6_ADDR_GEN_MODE

inet6_ifla6_size() is called to check how much space is needed by
inet6_fill_link_af() and inet6_fill_ifinfo(), both of which include
the IFLA_INET6_ADDR_GEN_MODE attribute. Reserve some room for it.

Fixes: bc91b0f07ada ("ipv6: addrconf: implement address generation modes")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: don't reinitialize ndev->cnf.addr_gen_mode on new inet6_dev

The value has already been copied from this netns's devconf_dflt, it
shouldn't be reset to the global kernel default.

Fixes: d35a00b8e33d ("net/ipv6: allow sysctl to change link-local address generation mode")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: fix addrconf_sysctl_addr_gen_mode

addrconf_sysctl_addr_gen_mode() has multiple problems. First, it ignores
the errors returned by proc_dointvec().

addrconf_sysctl_addr_gen_mode() calls proc_dointvec() directly, which
writes the value to memory, and then checks if it's valid and may return
EINVAL. If a bad value is given, the value displayed when reading
net.ipv6.conf.foo.addr_gen_mode next time will be invalid. In case the
value provided by the user was valid, addrconf_dev_config() won't be
called since idev->cnf.addr_gen_mode has already been updated.

Fix this in the usual way we deal with values that need to be checked
after the proc_do*() helper has returned: define a local ctl_table and
storage, call proc_dointvec() on that temporary area, then check and
store.

addrconf_sysctl_addr_gen_mode() also writes the new value to the global
ipv6_devconf_dflt, when we're writing to some netns's default, so that
new netns will inherit the value that was set by the change occuring in
any netns. That doesn't make any sense, so let's drop this assignment.

Finally, since addr_gen_mode is a __u32, switch to proc_douintvec().

Fixes: d35a00b8e33d ("net/ipv6: allow sysctl to change link-local address generation mode")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Fix updates to prefix route

Sowmini reported that a recent commit broke prefix routes for linklocal
addresses. The newly added modify_prefix_route is attempting to add a
new prefix route when the ifp priority does not match the route metric
however the check needs to account for the default priority. In addition,
the route add fails because the route already exists, and then the delete
removes the one that exists. Flip the order to do the delete first.

Fixes: 8308f3ff1753 ("net/ipv6: Add support for specifying metric of connected routes")
Reported-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Tested-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Ensure cfg is properly initialized in ipv6_create_tempaddr

Valdis reported a BUG in ipv6_add_addr:

[ 1820.832682] BUG: unable to handle kernel NULL pointer dereference at 0000000000000209
[ 1820.832728] RIP: 0010:ipv6_add_addr+0x280/0xd10
[ 1820.832732] Code: 49 8b 1f 0f 84 6a 0a 00 00 48 85 db 0f 84 4e 0a 00 00 48 8b 03 48 8b 53 08 49 89 45 00 49 8b 47 10
49 89 55 08 48 85 c0 74 15 <48> 8b 50 08 48 8b 00 49 89 95 b8 01 00 00 49 89 85 b0 01 00 00 4c
[ 1820.832847] RSP: 0018:ffffaa07c2fd7880 EFLAGS: 00010202
[ 1820.832853] RAX: 0000000000000201 RBX: ffffaa07c2fd79b0 RCX: 0000000000000000
[ 1820.832858] RDX: a4cfbfba2cbfa64c RSI: 0000000000000000 RDI: ffffffff8a8e9fa0
[ 1820.832862] RBP: ffffaa07c2fd7920 R08: 000000000000017a R09: ffffffff8a555300
[ 1820.832866] R10: 0000000000000000 R11: 0000000000000000 R12: ffff888d18e71c00
[ 1820.832871] R13: ffff888d0a9b1200 R14: 0000000000000000 R15: ffffaa07c2fd7980
[ 1820.832876] FS: 00007faa51bdb800(0000) GS:ffff888d1d400000(0000) knlGS:0000000000000000
[ 1820.832880] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1820.832885] CR2: 0000000000000209 CR3: 000000021e8f8001 CR4: 00000000001606e0
[ 1820.832888] Call Trace:
[ 1820.832898] ? __local_bh_enable_ip+0x119/0x260
[ 1820.832904] ? ipv6_create_tempaddr+0x259/0x5a0
[ 1820.832912] ? __local_bh_enable_ip+0x139/0x260
[ 1820.832921] ipv6_create_tempaddr+0x2da/0x5a0
[ 1820.832926] ? ipv6_create_tempaddr+0x2da/0x5a0
[ 1820.832941] manage_tempaddrs+0x1a5/0x240
[ 1820.832951] inet6_addr_del+0x20b/0x3b0
[ 1820.832959] ? nla_parse+0xce/0x1e0
[ 1820.832968] inet6_rtm_deladdr+0xd9/0x210
[ 1820.832981] rtnetlink_rcv_msg+0x1d4/0x5f0

Looking at the code I found 1 element (peer_pfx) of the newly introduced
ifa6_config struct that is not initialized. Use a memset rather than hard
coding an init for each struct element.

Reported-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Fixes: e6464b8c63619 ("net/ipv6: Convert ipv6_add_addr to struct ifa6_config")
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipv6: Generate random IID for addresses on RAWIP devices

RAWIP devices such as rmnet do not have a hardware address and
instead require the kernel to generate a random IID for the
IPv6 addresses.

Signed-off-by: Sean Tranchetti <stranche@codeaurora.org>
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Add support for specifying metric of connected routes

Add support for IFA_RT_PRIORITY to ipv6 addresses.

If the metric is changed on an existing address then the new route
is inserted before removing the old one. Since the metric is one
of the route keys, the prefix route can not be atomically replaced.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Pass ifa6_config struct to inet6_addr_modify

Update inet6_addr_modify to take ifa6_config argument versus a parameter
list. This is an argument move only; no functional change intended.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Pass ifa6_config struct to inet6_addr_add

Move the creation of struct ifa6_config up to callers of inet6_addr_add.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Convert ipv6_add_addr to struct ifa6_config

Move config parameters for adding an ipv6 address to a struct. struct
names stem from inet6_rtm_newaddr which is the modern handler for
adding an address.

Start the conversion to ifa6_config with ipv6_add_addr. This is an argument
move only; no functional change intended. Mapping of variable changes:

addr --> cfg->pfx
peer_addr --> cfg->peer_pfx
pfxlen --> cfg->plen
flags --> cfg->ifa_flags

scope, valid_lft, prefered_lft have the same names within cfg
(with corrected spelling).

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

proc: introduce proc_create_net{,_data}

Variants of proc_create{,_data} that directly take a struct seq_operations
and deal with network namespaces in ->open and ->release. All callers of
proc_create + seq_open_net converted over, and seq_{open,release}_net are
removed entirely.

Signed-off-by: Christoph Hellwig <hch@lst.de>

ipv6: addrconf: don't evaluate keep_addr_on_down twice

The addrconf_ifdown() evaluates keep_addr_on_down state twice. There
is no need to do it.

Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: Ivan Vecera <cera@cera.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Fix gfp_flags arg to addrconf_prefix_route

Eric noticed that __ipv6_ifa_notify is called under rcu_read_lock, so
the gfp argument to addrconf_prefix_route can not be GFP_KERNEL.

While scrubbing other calls I noticed addrconf_addr_gen has one
place with GFP_ATOMIC that can be GFP_KERNEL.

Fixes: acb54e3cba404 ("net/ipv6: Add gfp_flags to route add functions")
Reported-by: syzbot+2add39b05179b31f912f@syzkaller.appspotmail.com
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Remove aca_idev

aca_idev has only 1 user - inet6_fill_ifacaddr - and it only
wants the device index which can be extracted from the fib6_info
nexthop.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Rename addrconf_dst_alloc

addrconf_dst_alloc now returns a fib6_info. Update the name
and its users to reflect the change.

Rename only; no functional change intended.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Rename fib6_info struct elements

Change the prefix for fib6_info struct elements from rt6i_ to fib6_.
rt6i_pcpu and rt6i_exception_bucket are left as is given that they
point to rt6_info entries.

Rename only; not functional change intended.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Flip FIB entries to fib6_info

Convert all code paths referencing a FIB entry from
rt6_info to fib6_info.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: separate handling of FIB entries from dst based routes

Last step before flipping the data type for FIB entries:
- use fib6_info_alloc to create FIB entries in ip6_route_info_create
and addrconf_dst_alloc
- use fib6_info_release in place of dst_release, ip6_rt_put and
rt6_release
- remove the dst_hold before calling __ip6_ins_rt or ip6_del_rt
- when purging routes, drop per-cpu routes
- replace inc and dec of rt6i_ref with fib6_info_hold and fib6_info_release
- use rt->from since it points to the FIB entry
- drop references to exception bucket, fib6_metrics and per-cpu from
dst entries (those are relevant for fib entries only)

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Add gfp_flags to route add functions

Most FIB entries can be added using memory allocated with GFP_KERNEL.
Add gfp_flags to ip6_route_add and addrconf_dst_alloc. Code paths that
can be reached from the packet path (e.g., ndisc and autoconfig) or
atomic notifiers use GFP_ATOMIC; paths from user context (adding
addresses and routes) use GFP_KERNEL.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Move dst flags to booleans in fib entries

Continuing to wean FIB paths off of dst_entry, use a bool to hold
requests for certain dst settings. Add a helper to convert the
flags to DST flags when a FIB entry is converted to a dst_entry.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: move expires into rt6_info

Add expires to rt6_info for FIB entries, and add fib6 helpers to
manage it. Data path use of dst.expires remains.

The transition is fairly straightforward: when working with fib entries,
rt->dst.expires is just rt->expires, rt6_clean_expires is replaced with
fib6_clean_expires, rt6_set_expires becomes fib6_set_expires, and
rt6_check_expired becomes fib6_check_expired, where the fib6 versions
are added by this patch.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Move nexthop data to fib6_nh

Introduce fib6_nh structure and move nexthop related data from
rt6_info and rt6_info.dst to fib6_nh. References to dev, gateway or
lwtstate from a FIB lookup perspective are converted to use fib6_nh;
datapath references to dst version are left as is.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Save route type in rt6_info

The RTN_ type for IPv6 FIB entries is currently embedded in rt6i_flags
and dst.error. Since dst is going to be removed, it can no longer be
relied on for FIB dumps so save the route type as fib6_type.

fc_type is set in current users based on the algorithm in rt6_fill_node:
- rt6i_flags contains RTF_LOCAL: fc_type = RTN_LOCAL
- rt6i_flags contains RTF_ANYCAST: fc_type = RTN_ANYCAST
- else fc_type = RTN_UNICAST

Similarly, fib6_type is set in the rt6_info templates based on the
RTF_REJECT section of rt6_fill_node converting dst.error to RTN type.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Pass net namespace to route functions

Pass network namespace reference into route add, delete and get
functions.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: send netlink notifications for manually configured addresses

Send a netlink notification when userspace adds a manually configured
address if DAD is enabled and optimistic flag isn't set.
Moreover send RTM_DELADDR notifications for tentative addresses.

Some userspace applications (e.g. NetworkManager) are interested in
addr netlink events albeit the address is still in tentative state,
however events are not sent if DAD process is not completed.
If the address is added and immediately removed userspace listeners
are not notified. This behaviour can be easily reproduced by using
veth interfaces:

$ ip -b - <<EOF
> link add dev vm1 type veth peer name vm2
> link set dev vm1 up
> link set dev vm2 up
> addr add 2001:db8:a:b:1:2:3:4/64 dev vm1
> addr del 2001:db8:a:b:1:2:3:4/64 dev vm1
EOF

This patch reverts the behaviour introduced by the commit f784ad3d79e5
("ipv6: do not send RTM_DELADDR for tentative addresses")

Suggested-by: Thomas Haller <thaller@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: remove unnecessary check in addrconf_prefix_rcv_add_addr()

Remove unnecessary check on update_lft variable in
addrconf_prefix_rcv_add_addr routine since it is always set to 0.
Moreover remove update_lft re-initialization to 0

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Drop pernet_operations::async

Synchronous pernet_operations are not allowed anymore.
All are asynchronous. So, drop the structure member.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: addrconf: Use normal debugging style

Remove local ADBG macro and use netdev_dbg/pr_debug

Miscellanea:

o Remove unnecessary debug message after allocation failure as there
already is a dump_stack() on the failure paths
o Leave the allocation failure message on snmp6_alloc_dev as there
is one code path that does not do a dump_stack()

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Use octal not symbolic permissions

Prefer the direct use of octal for permissions.

Done with checkpatch -f --types=SYMBOLIC_PERMS --fix-inplace
and some typing.

Miscellanea:

o Whitespace neatening around these conversions.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Add l3mdev check to ipv6_chk_addr_and_flags

Lookup the L3 master device for the passed in device. Only consider
addresses on netdev's with the same master device. If the device is
not enslaved or is NULL, then the l3mdev is NULL which means only
devices not enslaved (ie, in the default domain) are considered.

Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Change address check to always take a device argument

ipv6_chk_addr_and_flags determines if an address is a local address and
optionally if it is an address on a specific device. For example, it is
called by ip6_route_info_create to determine if a given gateway address
is a local address. The address check currently does not consider L3
domains and as a result does not allow a route to be added in one VRF
if the nexthop points to an address in a second VRF. e.g.,

$ ip route add 2001:db8:1::/64 vrf r2 via 2001:db8:102::23
Error: Invalid gateway address.

where 2001:db8:102::23 is an address on an interface in vrf r1.

ipv6_chk_addr_and_flags needs to allow callers to always pass in a device
with a separate argument to not limit the address to the specific device.
The device is used used to determine the L3 domain of interest.

To that end add an argument to skip the device check and update callers
to always pass a device where possible and use the new argument to mean
any address in the domain.

Update a handful of users of ipv6_chk_addr with a NULL dev argument. This
patch handles the change to these callers without adding the domain check.

ip6_validate_gw needs to handle 2 cases - one where the device is given
as part of the nexthop spec and the other where the device is resolved.
There is at least 1 VRF case where deferring the check to only after
the route lookup has resolved the device fails with an unintuitive error
"RTNETLINK answers: No route to host" as opposed to the preferred
"Error: Gateway can not be a local address." The 'no route to host'
error is because of the fallback to a full lookup. The check is done
twice to avoid this error.

Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: allow userspace to add IFA_F_OPTIMISTIC addresses

According to RFC 4429 (section 3.1), adding new IPv6 addresses as
optimistic addresses is acceptable, as long as the implementation
follows some rules:

* Optimistic DAD SHOULD only be used when the implementation is aware
that the address is based on a most likely unique interface
identifier (such as in [RFC2464]), generated randomly [RFC3041],
or by a well-distributed hash function [RFC3972] or assigned by
Dynamic Host Configuration Protocol for IPv6 (DHCPv6) [RFC3315].
Optimistic DAD SHOULD NOT be used for manually entered
addresses.

Thus, it seems reasonable to allow userspace to set the optimistic flag
when adding new addresses.

We must not let userspace set NODAD + OPTIMISTIC, since if the kernel is
not performing DAD we would never clear the optimistic flag. We must
also ignore userspace's request to add OPTIMISTIC flag to addresses that
have already completed DAD (addresses that don't have the TENTATIVE
flag, or that have the DADFAILED flag).

Then we also need to clear the OPTIMISTIC flag on permanent addresses
when DAD fails. Otherwise, IFA_F_OPTIMISTIC addresses added by userspace
can still be used after DAD has failed, because in
ipv6_chk_addr_and_flags(), IFA_F_OPTIMISTIC overrides IFA_F_TENTATIVE.

Setting IFA_F_OPTIMISTIC from userspace is conditional on
CONFIG_IPV6_OPTIMISTIC_DAD and the optimistic_dad sysctl.

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Convert raw6_net_ops, udplite6_net_ops, ipv6_proc_ops, if6_proc_net_ops and ip6_route_net_late_ops

These pernet_operations create and destroy /proc entries
and safely may be converted and safely may be mark as async.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Convert addrconf_ops

These pernet_operations (un)register sysctl, which
are not touched by anybody else.

So, it's safe to make them async.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Andrei Vagin <avagin@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: addrconf: break critical section in addrconf_verify_rtnl()

Heiner reported a lockdep splat [1]

This is caused by attempting GFP_KERNEL allocation while RCU lock is
held and BH blocked.

We believe that addrconf_verify_rtnl() could run for a long period,
so instead of using GFP_ATOMIC here as Ido suggested, we should break
the critical section and restart it after the allocation.

[1]
[86220.125562] =============================
[86220.125586] WARNING: suspicious RCU usage
[86220.125612] 4.15.0-rc7-next-20180110+ #7 Not tainted
[86220.125641] -----------------------------
[86220.125666] kernel/sched/core.c:6026 Illegal context switch in RCU-bh read-side critical section!
[86220.125711]
other info that might help us debug this:

[86220.125755]
rcu_scheduler_active = 2, debug_locks = 1
[86220.125792] 4 locks held by kworker/0:2/1003:
[86220.125817] #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000da8e9b73>] process_one_work+0x1de/0x680
[86220.125895] #1: ((addr_chk_work).work){+.+.}, at: [<00000000da8e9b73>] process_one_work+0x1de/0x680
[86220.125959] #2: (rtnl_mutex){+.+.}, at: [<00000000b06d9510>] rtnl_lock+0x12/0x20
[86220.126017] #3: (rcu_read_lock_bh){....}, at: [<00000000aef52299>] addrconf_verify_rtnl+0x1e/0x510 [ipv6]
[86220.126111]
stack backtrace:
[86220.126142] CPU: 0 PID: 1003 Comm: kworker/0:2 Not tainted 4.15.0-rc7-next-20180110+ #7
[86220.126185] Hardware name: ZOTAC ZBOX-CI321NANO/ZBOX-CI321NANO, BIOS B246P105 06/01/2015
[86220.126250] Workqueue: ipv6_addrconf addrconf_verify_work [ipv6]
[86220.126288] Call Trace:
[86220.126312] dump_stack+0x70/0x9e
[86220.126337] lockdep_rcu_suspicious+0xce/0xf0
[86220.126365] ___might_sleep+0x1d3/0x240
[86220.126390] __might_sleep+0x45/0x80
[86220.126416] kmem_cache_alloc_trace+0x53/0x250
[86220.126458] ? ipv6_add_addr+0xfe/0x6e0 [ipv6]
[86220.126498] ipv6_add_addr+0xfe/0x6e0 [ipv6]
[86220.126538] ipv6_create_tempaddr+0x24d/0x430 [ipv6]
[86220.126580] ? ipv6_create_tempaddr+0x24d/0x430 [ipv6]
[86220.126623] addrconf_verify_rtnl+0x339/0x510 [ipv6]
[86220.126664] ? addrconf_verify_rtnl+0x339/0x510 [ipv6]
[86220.126708] addrconf_verify_work+0xe/0x20 [ipv6]
[86220.126738] process_one_work+0x258/0x680
[86220.126765] worker_thread+0x35/0x3f0
[86220.126790] kthread+0x124/0x140
[86220.126813] ? process_one_work+0x680/0x680
[86220.126839] ? kthread_create_worker_on_cpu+0x40/0x40
[86220.126869] ? umh_complete+0x40/0x40
[86220.126893] ? call_usermodehelper_exec_async+0x12a/0x160
[86220.126926] ret_from_fork+0x4b/0x60
[86220.126999] BUG: sleeping function called from invalid context at mm/slab.h:420
[86220.127041] in_atomic(): 1, irqs_disabled(): 0, pid: 1003, name: kworker/0:2
[86220.127082] 4 locks held by kworker/0:2/1003:
[86220.127107] #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000da8e9b73>] process_one_work+0x1de/0x680
[86220.127179] #1: ((addr_chk_work).work){+.+.}, at: [<00000000da8e9b73>] process_one_work+0x1de/0x680
[86220.127242] #2: (rtnl_mutex){+.+.}, at: [<00000000b06d9510>] rtnl_lock+0x12/0x20
[86220.127300] #3: (rcu_read_lock_bh){....}, at: [<00000000aef52299>] addrconf_verify_rtnl+0x1e/0x510 [ipv6]
[86220.127414] CPU: 0 PID: 1003 Comm: kworker/0:2 Not tainted 4.15.0-rc7-next-20180110+ #7
[86220.127463] Hardware name: ZOTAC ZBOX-CI321NANO/ZBOX-CI321NANO, BIOS B246P105 06/01/2015
[86220.127528] Workqueue: ipv6_addrconf addrconf_verify_work [ipv6]
[86220.127568] Call Trace:
[86220.127591] dump_stack+0x70/0x9e
[86220.127616] ___might_sleep+0x14d/0x240
[86220.127644] __might_sleep+0x45/0x80
[86220.127672] kmem_cache_alloc_trace+0x53/0x250
[86220.127717] ? ipv6_add_addr+0xfe/0x6e0 [ipv6]
[86220.127762] ipv6_add_addr+0xfe/0x6e0 [ipv6]
[86220.127807] ipv6_create_tempaddr+0x24d/0x430 [ipv6]
[86220.127854] ? ipv6_create_tempaddr+0x24d/0x430 [ipv6]
[86220.127903] addrconf_verify_rtnl+0x339/0x510 [ipv6]
[86220.127950] ? addrconf_verify_rtnl+0x339/0x510 [ipv6]
[86220.127998] addrconf_verify_work+0xe/0x20 [ipv6]
[86220.128032] process_one_work+0x258/0x680
[86220.128063] worker_thread+0x35/0x3f0
[86220.128091] kthread+0x124/0x140
[86220.128117] ? process_one_work+0x680/0x680
[86220.128146] ? kthread_create_worker_on_cpu+0x40/0x40
[86220.128180] ? umh_complete+0x40/0x40
[86220.128207] ? call_usermodehelper_exec_async+0x12a/0x160
[86220.128243] ret_from_fork+0x4b/0x60

Fixes: f3d9832e56c4 ("ipv6: addrconf: cleanup locking in ipv6_add_addr")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipv6: send unsolicited NA after DAD

Unsolicited IPv6 neighbor advertisements should be sent after DAD
completes. Update ndisc_send_unsol_na to skip tentative, non-optimistic
addresses and have those sent by addrconf_dad_completed after DAD.

Fixes: 4a6e3c5def13c ("net: ipv6: send unsolicited NA on admin up")
Reported-by: Vivek Venkatraman <vivek@cumulusnetworks.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: delete /proc THIS_MODULE references

/proc has been ignoring struct file_operations::owner field for 10 years.
Specifically, it started with commit 786d7e1612f0b0adb6046f19b906609e4fe8b1ba
("Fix rmmod/read/write races in /proc entries"). Notice the chunk where
inode->i_fop is initialized with proxy struct file_operations for
regular files:

- if (de->proc_fops)
- inode->i_fop = de->proc_fops;
+ if (de->proc_fops) {
+ if (S_ISREG(inode->i_mode))
+ inode->i_fop = &proc_reg_file_ops;
+ else
+ inode->i_fop = de->proc_fops;
+ }

VFS stopped pinning module at this point.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: Set nexthop flags upon carrier change

Similar to IPv4, when the carrier of a netdev changes we should toggle
the 'linkdown' flag on all the nexthops using it as their nexthop
device.

This will later allow us to test for the presence of this flag during
route lookup and dump.

Up until commit 4832c30d5458 ("net: ipv6: put host and anycast routes on
device with address") host and anycast routes used the loopback netdev
as their nexthop device and thus were not marked with the 'linkdown'
flag. The patch preserves this behavior and allows one to ping the local
address even when the nexthop device does not have a carrier and the
'ignore_routes_with_linkdown' sysctl is set.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: Prepare to handle multiple netdev events

To make IPv6 more in line with IPv4 we need to be able to respond
differently to different netdev events. For example, when a netdev is
unregistered all the routes using it as their nexthop device should be
flushed, whereas when the netdev's carrier changes only the 'linkdown'
flag should be toggled.

Currently, this is not possible, as the function that traverses the
routing tables is not aware of the triggering event.

Propagate the triggering event down, so that it could be used in later
patches.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: Clear nexthop flags upon netdev up

Previous patch marked nexthops with the 'dead' and 'linkdown' flags.
Clear these flags when the netdev comes back up.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rtnetlink: ipv6: convert remaining users to rtnl_register_module

convert remaining users of rtnl_register to rtnl_register_module
and un-export rtnl_register.

Requested-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

rtnetlink: remove __rtnl_register

This removes __rtnl_register and switches callers to either
rtnl_register or rtnl_register_module.

Also, rtnl_register() will now print an error if memory allocation
failed rather than panic the kernel.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

treewide: setup_timer() -> timer_setup()

This converts all remaining cases of the old setup_timer() API into using
timer_setup(), where the callback argument is the structure already
holding the struct timer_list. These should have no behavioral changes,
since they just change which pointer is passed into the callback with
the same available pointers after conversion. It handles the following
examples, in addition to some other variations.

Casting from unsigned long:

void my_callback(unsigned long data)
{
struct something *ptr = (struct something *)data;
...
}
...
setup_timer(&ptr->my_timer, my_callback, ptr);

and forced object casts:

void my_callback(struct something *ptr)
{
...
}
...
setup_timer(&ptr->my_timer, my_callback, (unsigned long)ptr);

become:

void my_callback(struct timer_list *t)
{
struct something *ptr = from_timer(ptr, t, my_timer);
...
}
...
timer_setup(&ptr->my_timer, my_callback, 0);

Direct function assignments:

void my_callback(unsigned long data)
{
struct something *ptr = (struct something *)data;
...
}
...
ptr->my_timer.function = my_callback;

have a temporary cast added, along with converting the args:

void my_callback(struct timer_list *t)
{
struct something *ptr = from_timer(ptr, t, my_timer);
...
}
...
ptr->my_timer.function = (TIMER_FUNC_TYPE)my_callback;

And finally, callbacks without a data assignment:

void my_callback(unsigned long data)
{
...
}
...
setup_timer(&ptr->my_timer, my_callback, 0);

have their argument renamed to verify they're unused during conversion:

void my_callback(struct timer_list *unused)
{
...
}
...
timer_setup(&ptr->my_timer, my_callback, 0);

The conversion is done with the following Coccinelle script:

spatch --very-quiet --all-includes --include-headers \
-I ./arch/x86/include -I ./arch/x86/include/generated \
-I ./include -I ./arch/x86/include/uapi \
-I ./arch/x86/include/generated/uapi -I ./include/uapi \
-I ./include/generated/uapi --include ./include/linux/kconfig.h \
--dir . \
--cocci-file ~/src/data/timer_setup.cocci

@fix_address_of@
expression e;
@@

setup_timer(
-&(e)
+&e
, ...)

// Update any raw setup_timer() usages that have a NULL callback, but
// would otherwise match change_timer_function_usage, since the latter
// will update all function assignments done in the face of a NULL
// function initialization in setup_timer().
@change_timer_function_usage_NULL@
expression _E;
identifier _timer;
type _cast_data;
@@

(
-setup_timer(&_E->_timer, NULL, _E);
+timer_setup(&_E->_timer, NULL, 0);
|
-setup_timer(&_E->_timer, NULL, (_cast_data)_E);
+timer_setup(&_E->_timer, NULL, 0);
|
-setup_timer(&_E._timer, NULL, &_E);
+timer_setup(&_E._timer, NULL, 0);
|
-setup_timer(&_E._timer, NULL, (_cast_data)&_E);
+timer_setup(&_E._timer, NULL, 0);
)

@change_timer_function_usage@
expression _E;
identifier _timer;
struct timer_list _stl;
identifier _callback;
type _cast_func, _cast_data;
@@

(
-setup_timer(&_E->_timer, _callback, _E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, &_callback, _E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, _callback, (_cast_data)_E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, &_callback, (_cast_data)_E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, (_cast_func)_callback, _E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, (_cast_func)&_callback, _E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, (_cast_func)_callback, (_cast_data)_E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, (_cast_func)&_callback, (_cast_data)_E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, (_cast_data)_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, (_cast_data)&_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, &_callback, (_cast_data)_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, &_callback, (_cast_data)&_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, (_cast_func)_callback, (_cast_data)_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, (_cast_func)_callback, (_cast_data)&_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, (_cast_func)&_callback, (_cast_data)_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, (_cast_func)&_callback, (_cast_data)&_E);
+timer_setup(&_E._timer, _callback, 0);
|
_E->_timer@_stl.function = _callback;
|
_E->_timer@_stl.function = &_callback;
|
_E->_timer@_stl.function = (_cast_func)_callback;
|
_E->_timer@_stl.function = (_cast_func)&_callback;
|
_E._timer@_stl.function = _callback;
|
_E._timer@_stl.function = &_callback;
|
_E._timer@_stl.function = (_cast_func)_callback;
|
_E._timer@_stl.function = (_cast_func)&_callback;
)

// callback(unsigned long arg)
@change_callback_handle_cast
depends on change_timer_function_usage@
identifier change_timer_function_usage._callback;
identifier change_timer_function_usage._timer;
type _origtype;
identifier _origarg;
type _handletype;
identifier _handle;
@@

void _callback(
-_origtype _origarg
+struct timer_list *t
)
{
(
... when != _origarg
_handletype *_handle =
-(_handletype *)_origarg;
+from_timer(_handle, t, _timer);
... when != _origarg
|
... when != _origarg
_handletype *_handle =
-(void *)_origarg;
+from_timer(_handle, t, _timer);
... when != _origarg
|
... when != _origarg
_handletype *_handle;
... when != _handle
_handle =
-(_handletype *)_origarg;
+from_timer(_handle, t, _timer);
... when != _origarg
|
... when != _origarg
_handletype *_handle;
... when != _handle
_handle =
-(void *)_origarg;
+from_timer(_handle, t, _timer);
... when != _origarg
)
}

// callback(unsigned long arg) without existing variable
@change_callback_handle_cast_no_arg
depends on change_timer_function_usage &&
!change_callback_handle_cast@
identifier change_timer_function_usage._callback;
identifier change_timer_function_usage._timer;
type _origtype;
identifier _origarg;
type _handletype;
@@

void _callback(
-_origtype _origarg
+struct timer_list *t
)
{
+ _handletype *_origarg = from_timer(_origarg, t, _timer);
+
... when != _origarg
- (_handletype *)_origarg
+ _origarg
... when != _origarg
}

// Avoid already converted callbacks.
@match_callback_converted
depends on change_timer_function_usage &&
!change_callback_handle_cast &&
!change_callback_handle_cast_no_arg@
identifier change_timer_function_usage._callback;
identifier t;
@@

void _callback(struct timer_list *t)
{ ... }

// callback(struct something *handle)
@change_callback_handle_arg
depends on change_timer_function_usage &&
!match_callback_converted &&
!change_callback_handle_cast &&
!change_callback_handle_cast_no_arg@
identifier change_timer_function_usage._callback;
identifier change_timer_function_usage._timer;
type _handletype;
identifier _handle;
@@

void _callback(
-_handletype *_handle
+struct timer_list *t
)
{
+ _handletype *_handle = from_timer(_handle, t, _timer);
...
}

// If change_callback_handle_arg ran on an empty function, remove
// the added handler.
@unchange_callback_handle_arg
depends on change_timer_function_usage &&
change_callback_handle_arg@
identifier change_timer_function_usage._callback;
identifier change_timer_function_usage._timer;
type _handletype;
identifier _handle;
identifier t;
@@

void _callback(struct timer_list *t)
{
- _handletype *_handle = from_timer(_handle, t, _timer);
}

// We only want to refactor the setup_timer() data argument if we've found
// the matching callback. This undoes changes in change_timer_function_usage.
@unchange_timer_function_usage
depends on change_timer_function_usage &&
!change_callback_handle_cast &&
!change_callback_handle_cast_no_arg &&
!change_callback_handle_arg@
expression change_timer_function_usage._E;
identifier change_timer_function_usage._timer;
identifier change_timer_function_usage._callback;
type change_timer_function_usage._cast_data;
@@

(
-timer_setup(&_E->_timer, _callback, 0);
+setup_timer(&_E->_timer, _callback, (_cast_data)_E);
|
-timer_setup(&_E._timer, _callback, 0);
+setup_timer(&_E._timer, _callback, (_cast_data)&_E);
)

// If we fixed a callback from a .function assignment, fix the
// assignment cast now.
@change_timer_function_assignment
depends on change_timer_function_usage &&
(change_callback_handle_cast ||
change_callback_handle_cast_no_arg ||
change_callback_handle_arg)@
expression change_timer_function_usage._E;
identifier change_timer_function_usage._timer;
identifier change_timer_function_usage._callback;
type _cast_func;
typedef TIMER_FUNC_TYPE;
@@

(
_E->_timer.function =
-_callback
+(TIMER_FUNC_TYPE)_callback
;
|
_E->_timer.function =
-&_callback
+(TIMER_FUNC_TYPE)_callback
;
|
_E->_timer.function =
-(_cast_func)_callback;
+(TIMER_FUNC_TYPE)_callback
;
|
_E->_timer.function =
-(_cast_func)&_callback
+(TIMER_FUNC_TYPE)_callback
;
|
_E._timer.function =
-_callback
+(TIMER_FUNC_TYPE)_callback
;
|
_E._timer.function =
-&_callback;
+(TIMER_FUNC_TYPE)_callback
;
|
_E._timer.function =
-(_cast_func)_callback
+(TIMER_FUNC_TYPE)_callback
;
|
_E._timer.function =
-(_cast_func)&_callback
+(TIMER_FUNC_TYPE)_callback
;
)

// Sometimes timer functions are called directly. Replace matched args.
@change_timer_function_calls
depends on change_timer_function_usage &&
(change_callback_handle_cast ||
change_callback_handle_cast_no_arg ||
change_callback_handle_arg)@
expression _E;
identifier change_timer_function_usage._timer;
identifier change_timer_function_usage._callback;
type _cast_data;
@@

_callback(
(
-(_cast_data)_E
+&_E->_timer
|
-(_cast_data)&_E
+&_E._timer
|
-_E
+&_E->_timer
)
)

// If a timer has been configured without a data argument, it can be
// converted without regard to the callback argument, since it is unused.
@match_timer_function_unused_data@
expression _E;
identifier _timer;
identifier _callback;
@@

(
-setup_timer(&_E->_timer, _callback, 0);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, _callback, 0L);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, _callback, 0UL);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, 0);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, 0L);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, 0UL);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_timer, _callback, 0);
+timer_setup(&_timer, _callback, 0);
|
-setup_timer(&_timer, _callback, 0L);
+timer_setup(&_timer, _callback, 0);
|
-setup_timer(&_timer, _callback, 0UL);
+timer_setup(&_timer, _callback, 0);
|
-setup_timer(_timer, _callback, 0);
+timer_setup(_timer, _callback, 0);
|
-setup_timer(_timer, _callback, 0L);
+timer_setup(_timer, _callback, 0);
|
-setup_timer(_timer, _callback, 0UL);
+timer_setup(_timer, _callback, 0);
)

@change_callback_unused_data
depends on match_timer_function_unused_data@
identifier match_timer_function_unused_data._callback;
type _origtype;
identifier _origarg;
@@

void _callback(
-_origtype _origarg
+struct timer_list *unused
)
{
... when != _origarg
}

Signed-off-by: Kees Cook <keescook@chromium.org>