net: ppp: make ppp_class constant

Since commit 43a7206b0963 ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so move the ppp_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240302-class_cleanup-net-next-v1-3-8fa378595b93@marliere.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ppp: constify the struct device_type usage

Since commit aed65af1cc2f ("drivers: make device_type const"), the driver
core can properly handle constant struct device_type. Move the ppp_type
variable to be a constant structure as well, placing it into read-only
memory which can not be modified at runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: fill in MODULE_DESCRIPTION()s for ppp

W=1 builds now warn if module is built without a MODULE_DESCRIPTION().
Add descriptions to the PPP modules.

Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/20240214152741.670178-6-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ppp: use standard array-copy-function

In ppp_generic.c, memdup_user() is utilized to copy a userspace array.
This is done without an overflow-check, which is, however, not critical
because the multiplicands are an unsigned short and struct sock_filter,
which is currently of size 8.

Regardless, string.h now provides memdup_array_user(), a wrapper for
copying userspace arrays in a standardized manner, which has the
advantage of making it more obvious to the reader that an array is being
copied.
The wrapper additionally performs an obligatory overflow check, saving
the reader the effort of analyzing the potential for overflow, and
making the code a bit more robust in case of future changes to the
multiplicands len * size.

Replace memdup_user() with memdup_array_user().

Suggested-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

driver core: class: remove module * from class_create()

The module pointer in class_create() never actually did anything, and it
shouldn't have been requred to be set as a parameter even if it did
something. So just remove it and fix up all callers of the function in
the kernel tree at the same time.

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20230313181843.1207845-4-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

use less confusing names for iov_iter direction initializers

READ/WRITE proved to be actively confusing - the meanings are
"data destination, as used with read(2)" and "data source, as
used with write(2)", but people keep interpreting those as
"we read data from it" and "we write data to it", i.e. exactly
the wrong way.

Call them ITER_DEST and ITER_SOURCE - at least that is harder
to misinterpret...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

ppp: associate skb with a device at tx

Syzkaller triggered flow dissector warning with the following:

r0 = openat$ppp(0xffffffffffffff9c, &(0x7f0000000000), 0xc0802, 0x0)
ioctl$PPPIOCNEWUNIT(r0, 0xc004743e, &(0x7f00000000c0))
ioctl$PPPIOCSACTIVE(r0, 0x40107446, &(0x7f0000000240)={0x2, &(0x7f0000000180)=[{0x20, 0x0, 0x0, 0xfffff034}, {0x6}]})
pwritev(r0, &(0x7f0000000040)=[{&(0x7f0000000140)='\x00!', 0x2}], 0x1, 0x0, 0x0)

[ 9.485814] WARNING: CPU: 3 PID: 329 at net/core/flow_dissector.c:1016 __skb_flow_dissect+0x1ee0/0x1fa0
[ 9.485929] skb_get_poff+0x53/0xa0
[ 9.485937] bpf_skb_get_pay_offset+0xe/0x20
[ 9.485944] ? ppp_send_frame+0xc2/0x5b0
[ 9.485949] ? _raw_spin_unlock_irqrestore+0x40/0x60
[ 9.485958] ? __ppp_xmit_process+0x7a/0xe0
[ 9.485968] ? ppp_xmit_process+0x5b/0xb0
[ 9.485974] ? ppp_write+0x12a/0x190
[ 9.485981] ? do_iter_write+0x18e/0x2d0
[ 9.485987] ? __import_iovec+0x30/0x130
[ 9.485997] ? do_pwritev+0x1b6/0x240
[ 9.486016] ? trace_hardirqs_on+0x47/0x50
[ 9.486023] ? __x64_sys_pwritev+0x24/0x30
[ 9.486026] ? do_syscall_64+0x3d/0x80
[ 9.486031] ? entry_SYSCALL_64_after_hwframe+0x63/0xcd

Flow dissector tries to find skb net namespace either via device
or via socket. Neigher is set in ppp_send_frame, so let's manually
use ppp->dev.

Cc: Paul Mackerras <paulus@samba.org>
Cc: linux-ppp@vger.kernel.org
Reported-by: syzbot+41cab52ab62ee99ed24a@syzkaller.appspotmail.com
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: Fix typo in comment

Delete the redundant word 'the'.

Signed-off-by: Xiang wangx <wangxiang@cdjrlc.com>
Link: https://lore.kernel.org/r/20220616142624.3397-1-wangxiang@cdjrlc.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ppp: ensure minimum packet size in ppp_write()

It seems pretty clear ppp layer assumed user space
would always be kind to provide enough data
in their write() to a ppp device.

This patch makes sure user provides at least
2 bytes.

It adds PPP_PROTO_LEN macro that could replace
in net-next many occurrences of hard-coded 2 value.

I replaced only one occurrence to ease backports
to stable kernels.

The bug manifests in the following report:

BUG: KMSAN: uninit-value in ppp_send_frame+0x28d/0x27c0 drivers/net/ppp/ppp_generic.c:1740
ppp_send_frame+0x28d/0x27c0 drivers/net/ppp/ppp_generic.c:1740
__ppp_xmit_process+0x23e/0x4b0 drivers/net/ppp/ppp_generic.c:1640
ppp_xmit_process+0x1fe/0x480 drivers/net/ppp/ppp_generic.c:1661
ppp_write+0x5cb/0x5e0 drivers/net/ppp/ppp_generic.c:513
do_iter_write+0xb0c/0x1500 fs/read_write.c:853
vfs_writev fs/read_write.c:924 [inline]
do_writev+0x645/0xe00 fs/read_write.c:967
__do_sys_writev fs/read_write.c:1040 [inline]
__se_sys_writev fs/read_write.c:1037 [inline]
__x64_sys_writev+0xe5/0x120 fs/read_write.c:1037
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x44/0xae

Uninit was created at:
slab_post_alloc_hook mm/slab.h:524 [inline]
slab_alloc_node mm/slub.c:3251 [inline]
__kmalloc_node_track_caller+0xe0c/0x1510 mm/slub.c:4974
kmalloc_reserve net/core/skbuff.c:354 [inline]
__alloc_skb+0x545/0xf90 net/core/skbuff.c:426
alloc_skb include/linux/skbuff.h:1126 [inline]
ppp_write+0x11d/0x5e0 drivers/net/ppp/ppp_generic.c:501
do_iter_write+0xb0c/0x1500 fs/read_write.c:853
vfs_writev fs/read_write.c:924 [inline]
do_writev+0x645/0xe00 fs/read_write.c:967
__do_sys_writev fs/read_write.c:1040 [inline]
__se_sys_writev fs/read_write.c:1037 [inline]
__x64_sys_writev+0xe5/0x120 fs/read_write.c:1037
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x44/0xae

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linux-ppp@vger.kernel.org
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: add netns refcount tracker

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

ppp: use the correct function to check if a netdev name is in use

A new helper to detect if a net device name is in use was added. Use it
here as the return reference from __dev_get_by_name was discarded.

Signed-off-by: Antoine Tenart <atenart@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

bpf: Refactor BPF_PROG_RUN into a function

Turn BPF_PROG_RUN into a proper always inlined function. No functional and
performance changes are intended, but it makes it much easier to understand
what's going on with how BPF programs are actually get executed. It's more
obvious what types and callbacks are expected. Also extra () around input
parameters can be dropped, as well as `__` variable prefixes intended to avoid
naming collisions, which makes the code simpler to read and write.

This refactoring also highlighted one extra issue. BPF_PROG_RUN is both
a macro and an enum value (BPF_PROG_RUN == BPF_PROG_TEST_RUN). Turning
BPF_PROG_RUN into a function causes naming conflict compilation error. So
rename BPF_PROG_RUN into lower-case bpf_prog_run(), similar to
bpf_prog_run_xdp(), bpf_prog_run_pin_on_cpu(), etc. All existing callers of
BPF_PROG_RUN, the macro, are switched to bpf_prog_run() explicitly.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210815070609.987780-2-andrii@kernel.org

ppp: use ndo_siocdevprivate

ppp has a custom statistics interface using SIOCDEVPRIVATE
ioctl commands that works correctly in compat mode.

Convert it to use ndo_siocdevprivate as a cleanup.

Cc: Paul Mackerras <paulus@samba.org>
Cc: linux-ppp@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: Fix generating ppp unit id when ifname is not specified

When registering new ppp interface via PPPIOCNEWUNIT ioctl then kernel has
to choose interface name as this ioctl API does not support specifying it.

Kernel in this case register new interface with name "ppp<id>" where <id>
is the ppp unit id, which can be obtained via PPPIOCGUNIT ioctl. This
applies also in the case when registering new ppp interface via rtnl
without supplying IFLA_IFNAME.

PPPIOCNEWUNIT ioctl allows to specify own ppp unit id which will kernel
assign to ppp interface, in case this ppp id is not already used by other
ppp interface.

In case user does not specify ppp unit id then kernel choose the first free
ppp unit id. This applies also for case when creating ppp interface via
rtnl method as it does not provide a way for specifying own ppp unit id.

If some network interface (does not have to be ppp) has name "ppp<id>"
with this first free ppp id then PPPIOCNEWUNIT ioctl or rtnl call fails.

And registering new ppp interface is not possible anymore, until interface
which holds conflicting name is renamed. Or when using rtnl method with
custom interface name in IFLA_IFNAME.

As list of allocated / used ppp unit ids is not possible to retrieve from
kernel to userspace, userspace has no idea what happens nor which interface
is doing this conflict.

So change the algorithm how ppp unit id is generated. And choose the first
number which is not neither used as ppp unit id nor in some network
interface with pattern "ppp<id>".

This issue can be simply reproduced by following pppd call when there is no
ppp interface registered and also no interface with name pattern "ppp<id>":

pppd ifname ppp1 +ipv6 noip noauth nolock local nodetach pty "pppd +ipv6 noip noauth nolock local nodetach notty"

Or by creating the one ppp interface (which gets assigned ppp unit id 0),
renaming it to "ppp1" and then trying to create a new ppp interface (which
will always fails as next free ppp unit id is 1, but network interface with
name "ppp1" exists).

This patch fixes above described issue by generating new and new ppp unit
id until some non-conflicting id with network interfaces is generated.

Signed-off-by: Pali Rohár <pali@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: Fix generating ifname when empty IFLA_IFNAME is specified

IFLA_IFNAME is nul-term string which means that IFLA_IFNAME buffer can be
larger than length of string which contains.

Function __rtnl_newlink() generates new own ifname if either IFLA_IFNAME
was not specified at all or userspace passed empty nul-term string.

It is expected that if userspace does not specify ifname for new ppp netdev
then kernel generates one in format "ppp<id>" where id matches to the ppp
unit id which can be later obtained by PPPIOCGUNIT ioctl.

And it works in this way if IFLA_IFNAME is not specified at all. But it
does not work when IFLA_IFNAME is specified with empty string.

So fix this logic also for empty IFLA_IFNAME in ppp_nl_newlink() function
and correctly generates ifname based on ppp unit identifier if userspace
did not provided preferred ifname.

Without this patch when IFLA_IFNAME was specified with empty string then
kernel created a new ppp interface in format "ppp<id>" but id did not
match ppp unit id returned by PPPIOCGUNIT ioctl. In this case id was some
number generated by __rtnl_newlink() function.

Signed-off-by: Pali Rohár <pali@kernel.org>
Fixes: bb8082f69138 ("ppp: build ifname using unit identifier for rtnl based devices")
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ppp: resolve forwarding path for bridge pppoe devices

Pass on the PPPoE session ID, destination hardware address and the real
device.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: fix refcount underflow on channel unbridge

When setting up a channel bridge, ppp_bridge_channels sets the
pch->bridge field before taking the associated reference on the bridge
file instance.

This opens up a refcount underflow bug if ppp_bridge_channels called
via. iotcl runs concurrently with ppp_unbridge_channels executing via.
file release.

The bug is triggered by ppp_bridge_channels taking the error path
through the 'err_unset' label. In this scenario, pch->bridge is set,
but the reference on the bridged channel will not be taken because
the function errors out. If ppp_unbridge_channels observes pch->bridge
before it is unset by the error path, it will erroneously drop the
reference on the bridged channel and cause a refcount underflow.

To avoid this, ensure that ppp_bridge_channels holds a reference on
each channel in advance of setting the bridge pointers.

Signed-off-by: Tom Parkin <tparkin@katalix.com>
Fixes: 4cf476ced45d ("ppp: add PPPIOCBRIDGECHAN and PPPIOCUNBRIDGECHAN ioctls")
Acked-by: Guillaume Nault <gnault@redhat.com>
Link: https://lore.kernel.org/r/20210107181315.3128-1-tparkin@katalix.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ppp: add PPPIOCBRIDGECHAN and PPPIOCUNBRIDGECHAN ioctls

This new ioctl pair allows two ppp channels to be bridged together:
frames arriving in one channel are transmitted in the other channel
and vice versa.

The practical use for this is primarily to support the L2TP Access
Concentrator use-case. The end-user session is presented as a ppp
channel (typically PPPoE, although it could be e.g. PPPoA, or even PPP
over a serial link) and is switched into a PPPoL2TP session for
transmission to the LNS. At the LNS the PPP session is terminated in
the ISP's network.

When a PPP channel is bridged to another it takes a reference on the
other's struct ppp_file. This reference is dropped when the channels
are unbridged, which can occur either explicitly on userspace calling
the PPPIOCUNBRIDGECHAN ioctl, or implicitly when either channel in the
bridge is unregistered.

In order to implement the channel bridge, struct channel is extended
with a new field, 'bridge', which points to the other struct channel
making up the bridge.

This pointer is RCU protected to avoid adding another lock to the data
path.

To guard against concurrent writes to the pointer, the existing struct
channel lock 'upl' coverage is extended rather than adding a new lock.

The 'upl' lock is used to protect the existing unit pointer. Since the
bridge effectively replaces the unit (they're mutually exclusive for a
channel) it makes coding easier to use the same lock to cover them
both.

Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: partially revert dynamic lockdep key changes

This patch reverts the folowing commits:

commit 064ff66e2bef84f1153087612032b5b9eab005bd
"bonding: add missing netdev_update_lockdep_key()"

commit 53d374979ef147ab51f5d632dfe20b14aebeccd0
"net: avoid updating qdisc_xmit_lock_key in netdev_update_lockdep_key()"

commit 1f26c0d3d24125992ab0026b0dab16c08df947c7
"net: fix kernel-doc warning in <linux/netdevice.h>"

commit ab92d68fc22f9afab480153bd82a20f6e2533769
"net: core: add generic lockdep keys"

but keeps the addr_list_lock_key because we still lock
addr_list_lock nestedly on stack devices, unlikely xmit_lock
this is safe because we don't take addr_list_lock on any fast
path.

Reported-and-tested-by: syzbot+aaa6fa4949cc5d9b7b25@syzkaller.appspotmail.com
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: Remove redundant BUG_ON() check in ppp_pernet

Passing NULL to ppp_pernet causes a crash via BUG_ON.
Dereferencing net in net_generic() also has the same effect.
This patch removes the redundant BUG_ON check on the same parameter.

Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: fix out-of-bounds access in bpf_prog_create()

sock_fprog_kern::len is in units of struct sock_filter, not bytes.

Fixes: 3e859adf3643 ("compat_ioctl: unify copy-in of ppp filters")
Reported-by: syzbot+eb853b51b10f1befa0b7@syzkaller.appspotmail.com
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: core: add generic lockdep keys

Some interface types could be nested.
(VLAN, BONDING, TEAM, MACSEC, MACVLAN, IPVLAN, VIRT_WIFI, VXLAN, etc..)
These interface types should set lockdep class because, without lockdep
class key, lockdep always warn about unexisting circular locking.

In the current code, these interfaces have their own lockdep class keys and
these manage itself. So that there are so many duplicate code around the
/driver/net and /net/.
This patch adds new generic lockdep keys and some helper functions for it.

This patch does below changes.
a) Add lockdep class keys in struct net_device
- qdisc_running, xmit, addr_list, qdisc_busylock
- these keys are used as dynamic lockdep key.
b) When net_device is being allocated, lockdep keys are registered.
- alloc_netdev_mqs()
c) When net_device is being free'd llockdep keys are unregistered.
- free_netdev()
d) Add generic lockdep key helper function
- netdev_register_lockdep_key()
- netdev_unregister_lockdep_key()
- netdev_update_lockdep_key()
e) Remove unnecessary generic lockdep macro and functions
f) Remove unnecessary lockdep code of each interfaces.

After this patch, each interface modules don't need to maintain
their lockdep keys.

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

compat_ioctl: ppp: move simple commands into ppp_generic.c

All ppp commands that are not already handled in ppp_compat_ioctl()
are compatible, so they can now handled by calling the native
ppp_ioctl() directly.

Without CONFIG_BLOCK, the generic compat_ioctl table is now empty,
so add a check to avoid a build failure in the looking function for
that configuration.

Cc: netdev@vger.kernel.org
Cc: linux-ppp@vger.kernel.org
Cc: Paul Mackerras <paulus@samba.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

compat_ioctl: handle PPPIOCGIDLE for 64-bit time_t

The ppp_idle structure is defined in terms of __kernel_time_t, which is
defined as 'long' on all architectures, and this usage is not affected
by the y2038 problem since it transports a time interval rather than an
absolute time.

However, the ppp user space defines the same structure as time_t, which
may be 64-bit wide on new libc versions even on 32-bit architectures.

It's easy enough to just handle both possible structure layouts on
all architectures, to deal with the possibility that a user space ppp
implementation comes with its own ppp_idle structure definition, as well
as to document the fact that the driver is y2038-safe.

Doing this also avoids the need for a special compat mode translation,
since 32-bit and 64-bit kernels now support the same interfaces. The old
32-bit structure is also available on native 64-bit architectures now,
but this is harmless.

Cc: netdev@vger.kernel.org
Cc: linux-ppp@vger.kernel.org
Cc: Paul Mackerras <paulus@samba.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

compat_ioctl: move PPPIOCSCOMPRESS to ppp_generic

Rather than using a compat_alloc_user_space() buffer, moving
this next to the native handler allows sharing most of
the code, leaving only the user copy portion distinct.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: netdev@vger.kernel.org
Cc: linux-ppp@vger.kernel.org
Cc: Paul Mackerras <paulus@samba.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

compat_ioctl: unify copy-in of ppp filters

Now that isdn4linux is gone, the is only one implementation of PPPIOCSPASS
and PPPIOCSACTIVE in ppp_generic.c, so this is where the compat_ioctl
support should be implemented.

The two commands are implemented in very similar ways, so introduce
new helpers to allow sharing between the two and between native and
compat mode.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[arnd: rebased, and added changelog text]
Cc: netdev@vger.kernel.org
Cc: linux-ppp@vger.kernel.org
Cc: Paul Mackerras <paulus@samba.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

ppp: Fix memory leak in ppp_write

When ppp is closing, __ppp_xmit_process() failed to enqueue skb
and skb allocated in ppp_write() is leaked.

syzbot reported :
BUG: memory leak
unreferenced object 0xffff88812a17bc00 (size 224):
comm "syz-executor673", pid 6952, jiffies 4294942888 (age 13.040s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<00000000d110fff9>] kmemleak_alloc_recursive include/linux/kmemleak.h:43 [inline]
[<00000000d110fff9>] slab_post_alloc_hook mm/slab.h:522 [inline]
[<00000000d110fff9>] slab_alloc_node mm/slab.c:3262 [inline]
[<00000000d110fff9>] kmem_cache_alloc_node+0x163/0x2f0 mm/slab.c:3574
[<000000002d616113>] __alloc_skb+0x6e/0x210 net/core/skbuff.c:197
[<000000000167fc45>] alloc_skb include/linux/skbuff.h:1055 [inline]
[<000000000167fc45>] ppp_write+0x48/0x120 drivers/net/ppp/ppp_generic.c:502
[<000000009ab42c0b>] __vfs_write+0x43/0xa0 fs/read_write.c:494
[<00000000086b2e22>] vfs_write fs/read_write.c:558 [inline]
[<00000000086b2e22>] vfs_write+0xee/0x210 fs/read_write.c:542
[<00000000a2b70ef9>] ksys_write+0x7c/0x130 fs/read_write.c:611
[<00000000ce5e0fdd>] __do_sys_write fs/read_write.c:623 [inline]
[<00000000ce5e0fdd>] __se_sys_write fs/read_write.c:620 [inline]
[<00000000ce5e0fdd>] __x64_sys_write+0x1e/0x30 fs/read_write.c:620
[<00000000d9d7b370>] do_syscall_64+0x76/0x1a0 arch/x86/entry/common.c:296
[<0000000006e6d506>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fix this by freeing skb, if ppp is closing.

Fixes: 6d066734e9f0 ("ppp: avoid loop in xmit recursion detection code")
Reported-and-tested-by: syzbot+d9c8bf24e56416d7ce2c@syzkaller.appspotmail.com
Signed-off-by: Takeshi Misawa <jeliantsurux@gmail.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Tested-by: Guillaume Nault <gnault@redhat.com>
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>

ppp: Move PFC decompression to PPP generic layer

Extract "Protocol" field decompression code from transport protocols to
PPP generic layer, where it actually belongs. As a consequence, this
patch fixes incorrect place of PFC decompression in L2TP driver (when
it's not PPPOX_BOUND) and also enables this decompression for other
protocols, like PPPoE.

Protocol field decompression also happens in PPP Multilink Protocol
code and in PPP compression protocols implementations (bsd, deflate,
mppe). It looks like there is no easy way to get rid of that, so it was
decided to leave it as is, but provide those cases with appropriate
comments instead.

Changes in v2:
- Fix the order of checking skb data room and proto decompression
- Remove "inline" keyword from ppp_decompress_proto()
- Don't split line before function name
- Prefix ppp_decompress_proto() function with "__"
- Add ppp_decompress_proto() function with skb data room checks
- Add description for introduced functions
- Fix comments (as per review on mailing list)

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: Remove direct skb_queue_head list pointer access.

Add a helper, __skb_peek(), and use it in ppp_mp_reconstruct().

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

ppp: remove the PPPIOCDETACH ioctl

The PPPIOCDETACH ioctl effectively tries to "close" the given ppp file
before f_count has reached 0, which is fundamentally a bad idea. It
does check 'f_count < 2', which excludes concurrent operations on the
file since they would only be possible with a shared fd table, in which
case each fdget() would take a file reference. However, it fails to
account for the fact that even with 'f_count == 1' the file can still be
linked into epoll instances. As reported by syzbot, this can trivially
be used to cause a use-after-free.

Yet, the only known user of PPPIOCDETACH is pppd versions older than
ppp-2.4.2, which was released almost 15 years ago (November 2003).
Also, PPPIOCDETACH apparently stopped working reliably at around the
same time, when the f_count check was added to the kernel, e.g. see
https://lkml.org/lkml/2002/12/31/83. Also, the current 'f_count < 2'
check makes PPPIOCDETACH only work in single-threaded applications; it
always fails if called from a multithreaded application.

All pppd versions released in the last 15 years just close() the file
descriptor instead.

Therefore, instead of hacking around this bug by exporting epoll
internals to modules, and probably missing other related bugs, just
remove the PPPIOCDETACH ioctl and see if anyone actually notices. Leave
a stub in place that prints a one-time warning and returns EINVAL.

Reported-by: syzbot+16363c99d4134717c05b@syzkaller.appspotmail.com
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Reviewed-by: Guillaume Nault <g.nault@alphalink.fr>
Tested-by: Guillaume Nault <g.nault@alphalink.fr>
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>

drivers/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>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: avoid loop in xmit recursion detection code

We already detect situations where a PPP channel sends packets back to
its upper PPP device. While this is enough to avoid deadlocking on xmit
locks, this doesn't prevent packets from looping between the channel
and the unit.

The problem is that ppp_start_xmit() enqueues packets in ppp->file.xq
before checking for xmit recursion. Therefore, __ppp_xmit_process()
might dequeue a packet from ppp->file.xq and send it on the channel
which, in turn, loops it back on the unit. Then ppp_start_xmit()
queues the packet back to ppp->file.xq and __ppp_xmit_process() picks
it up and sends it again through the channel. Therefore, the packet
will loop between __ppp_xmit_process() and ppp_start_xmit() until some
other part of the xmit path drops it.

For L2TP, we rapidly fill the skb's headroom and pppol2tp_xmit() drops
the packet after a few iterations. But PPTP reallocates the headroom
if necessary, letting the loop run and exhaust the machine resources
(as reported in https://bugzilla.kernel.org/show_bug.cgi?id=199109).

Fix this by letting __ppp_xmit_process() enqueue the skb to
ppp->file.xq, so that we can check for recursion before adding it to
the queue. Now ppp_xmit_process() can drop the packet when recursion is
detected.

__ppp_channel_push() is a bit special. It calls __ppp_xmit_process()
without having any actual packet to send. This is used by
ppp_output_wakeup() to re-enable transmission on the parent unit (for
implementations like ppp_async.c, where the .start_xmit() function
might not consume the skb, leaving it in ppp->xmit_pending and
disabling transmission).
Therefore, __ppp_xmit_process() needs to handle the case where skb is
NULL, dequeuing as many packets as possible from ppp->file.xq.

Reported-by: xu heng <xuheng333@zoho.com>
Fixes: 55454a565836 ("ppp: avoid dealock on recursive xmit")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: prevent unregistered channels from connecting to PPP units

PPP units don't hold any reference on the channels connected to it.
It is the channel's responsibility to ensure that it disconnects from
its unit before being destroyed.
In practice, this is ensured by ppp_unregister_channel() disconnecting
the channel from the unit before dropping a reference on the channel.

However, it is possible for an unregistered channel to connect to a PPP
unit: register a channel with ppp_register_net_channel(), attach a
/dev/ppp file to it with ioctl(PPPIOCATTCHAN), unregister the channel
with ppp_unregister_channel() and finally connect the /dev/ppp file to
a PPP unit with ioctl(PPPIOCCONNECT).

Once in this situation, the channel is only held by the /dev/ppp file,
which can be released at anytime and free the channel without letting
the parent PPP unit know. Then the ppp structure ends up with dangling
pointers in its ->channels list.

Prevent this scenario by forbidding unregistered channels from
connecting to PPP units. This maintains the code logic by keeping
ppp_unregister_channel() responsible from disconnecting the channel if
necessary and avoids modification on the reference counting mechanism.

This issue seems to predate git history (successfully reproduced on
Linux 2.6.26 and earlier PPP commits are unrelated).

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Convert ppp_net_ops

These pernet_operations are similar to bond_net_ops. Exit method
unregisters all net ppp devices, and it looks like another
pernet_operations are not interested in foreign net ppp list.
So, it's possible to mark them async.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

vfs: do bulk POLL* -> EPOLL* replacement

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do. But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ppp: unlock all_ppp_mutex before registering device

ppp_dev_uninit(), which is the .ndo_uninit() handler of PPP devices,
needs to lock pn->all_ppp_mutex. Therefore we mustn't call
register_netdevice() with pn->all_ppp_mutex already locked, or we'd
deadlock in case register_netdevice() fails and calls .ndo_uninit().

Fortunately, we can unlock pn->all_ppp_mutex before calling
register_netdevice(). This lock protects pn->units_idr, which isn't
used in the device registration process.

However, keeping pn->all_ppp_mutex locked during device registration
did ensure that no device in transient state would be published in
pn->units_idr. In practice, unlocking it before calling
register_netdevice() doesn't change this property: ppp_unit_register()
is called with 'ppp_mutex' locked and all searches done in
pn->units_idr hold this lock too.

Fixes: 8cb775bc0a34 ("ppp: fix device unregistration upon netns deletion")
Reported-and-tested-by: syzbot+367889b9c9e279219175@syzkaller.appspotmail.com
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

the rest of drivers/*: annotate ->poll() instances

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

ppp: exit_net cleanup checks added

Be sure that lists initialized in net_init hook were return
to initial state.

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

ppp: Destroy the mutex when cleanup

The mutex_destroy only makes sense when enable DEBUG_MUTEX. For the
good readbility, it's better to invoke it in exit func when the init
func invokes mutex_init.

Signed-off-by: Gao Feng <gfree.wind@vip.163.com>
Acked-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: allow usage in namespaces

Check for CAP_NET_ADMIN with ns_capable() instead of capable()
to allow usage of ppp in user namespace other than the init one.

Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers, net, ppp: convert ppp_file.refcnt from atomic_t to refcount_t

atomic_t variables are currently used to implement reference
counters with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)

Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.

The variable ppp_file.refcnt is used as pure reference counter.
Convert it to refcount_t and fix up the operations.

Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: fix race in ppp device destruction

ppp_release() tries to ensure that netdevices are unregistered before
decrementing the unit refcount and running ppp_destroy_interface().

This is all fine as long as the the device is unregistered by
ppp_release(): the unregister_netdevice() call, followed by
rtnl_unlock(), guarantee that the unregistration process completes
before rtnl_unlock() returns.

However, the device may be unregistered by other means (like
ppp_nl_dellink()). If this happens right before ppp_release() calling
rtnl_lock(), then ppp_release() has to wait for the concurrent
unregistration code to release the lock.
But rtnl_unlock() releases the lock before completing the device
unregistration process. This allows ppp_release() to proceed and
eventually call ppp_destroy_interface() before the unregistration
process completes. Calling free_netdev() on this partially unregistered
device will BUG():

------------[ cut here ]------------
kernel BUG at net/core/dev.c:8141!
invalid opcode: 0000 [#1] SMP

CPU: 1 PID: 1557 Comm: pppd Not tainted 4.14.0-rc2+ #4
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1.fc26 04/01/2014

Call Trace:
ppp_destroy_interface+0xd8/0xe0 [ppp_generic]
ppp_disconnect_channel+0xda/0x110 [ppp_generic]
ppp_unregister_channel+0x5e/0x110 [ppp_generic]
pppox_unbind_sock+0x23/0x30 [pppox]
pppoe_connect+0x130/0x440 [pppoe]
SYSC_connect+0x98/0x110
? do_fcntl+0x2c0/0x5d0
SyS_connect+0xe/0x10
entry_SYSCALL_64_fastpath+0x1a/0xa5

RIP: free_netdev+0x107/0x110 RSP: ffffc28a40573d88
---[ end trace ed294ff0cc40eeff ]---

We could set the ->needs_free_netdev flag on PPP devices and move the
ppp_destroy_interface() logic in the ->priv_destructor() callback. But
that'd be quite intrusive as we'd first need to unlink from the other
channels and units that depend on the device (the ones that used the
PPPIOCCONNECT and PPPIOCATTACH ioctls).

Instead, we can just let the netdevice hold a reference on its
ppp_file. This reference is dropped in ->priv_destructor(), at the very
end of the unregistration process, so that neither ppp_release() nor
ppp_disconnect_channel() can call ppp_destroy_interface() in the interim.

Reported-by: Beniamino Galvani <bgalvani@redhat.com>
Fixes: 8cb775bc0a34 ("ppp: fix device unregistration upon netns deletion")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: fix __percpu annotation

Move sparse annotation right after pointer type.

Fixes sparse warning:
drivers/net/ppp/ppp_generic.c:1422:13: warning: incorrect type in initializer (different address spaces)
drivers/net/ppp/ppp_generic.c:1422:13: expected void const [noderef] <asn:3>*__vpp_verify
drivers/net/ppp/ppp_generic.c:1422:13: got int *<noident>
...

Fixes: e5dadc65f9e0 ("ppp: Fix false xmit recursion detect with two ppp devices")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: fix xmit recursion detection on ppp channels

Commit e5dadc65f9e0 ("ppp: Fix false xmit recursion detect with two ppp
devices") dropped the xmit_recursion counter incrementation in
ppp_channel_push() and relied on ppp_xmit_process() for this task.
But __ppp_channel_push() can also send packets directly (using the
.start_xmit() channel callback), in which case the xmit_recursion
counter isn't incremented anymore. If such packets get routed back to
the parent ppp unit, ppp_xmit_process() won't notice the recursion and
will call ppp_channel_push() on the same channel, effectively creating
the deadlock situation that the xmit_recursion mechanism was supposed
to prevent.

This patch re-introduces the xmit_recursion counter incrementation in
ppp_channel_push(). Since the xmit_recursion variable is now part of
the parent ppp unit, incrementation is skipped if the channel doesn't
have any. This is fine because only packets routed through the parent
unit may enter the channel recursively.

Finally, we have to ensure that pch->ppp is not going to be modified
while executing ppp_channel_push(). Instead of taking this lock only
while calling ppp_xmit_process(), we now have to hold it for the full
ppp_channel_push() execution. This respects the ppp locks ordering
which requires locking ->upl before ->downl.

Fixes: e5dadc65f9e0 ("ppp: Fix false xmit recursion detect with two ppp devices")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: Fix false xmit recursion detect with two ppp devices

The global percpu variable ppp_xmit_recursion is used to detect the ppp
xmit recursion to avoid the deadlock, which is caused by one CPU tries to
lock the xmit lock twice. But it would report false recursion when one CPU
wants to send the skb from two different PPP devices, like one L2TP on the
PPPoE. It is a normal case actually.

Now use one percpu member of struct ppp instead of the gloable variable to
detect the xmit recursion of one ppp device.

Fixes: 55454a565836 ("ppp: avoid dealock on recursive xmit")
Signed-off-by: Gao Feng <gfree.wind@vip.163.com>
Signed-off-by: Liu Jianying <jianying.liu@ikuai8.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: add netlink_ext_ack argument to rtnl_link_ops.validate

Add support for extended error reporting.

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: add netlink_ext_ack argument to rtnl_link_ops.newlink

Add support for extended error reporting.

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

networking: make skb_push & __skb_push return void pointers

It seems like a historic accident that these return unsigned char *,
and in many places that means casts are required, more often than not.

Make these functions return void * and remove all the casts across
the tree, adding a (u8 *) cast only where the unsigned char pointer
was used directly, all done with the following spatch:

@@
expression SKB, LEN;
typedef u8;
identifier fn = { skb_push, __skb_push, skb_push_rcsum };
@@
- *(fn(SKB, LEN))
+ *(u8 *)fn(SKB, LEN)

@@
expression E, SKB, LEN;
identifier fn = { skb_push, __skb_push, skb_push_rcsum };
type T;
@@
- E = ((T *)(fn(SKB, LEN)))
+ E = fn(SKB, LEN)

@@
expression SKB, LEN;
identifier fn = { skb_push, __skb_push, skb_push_rcsum };
@@
- fn(SKB, LEN)[0]
+ *(u8 *)fn(SKB, LEN)

Note that the last part there converts from push(...)[0] to the
more idiomatic *(u8 *)push(...).

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

ppp: remove unnecessary bh disable in xmit path

Since the commit 55454a565836 ("ppp: avoid dealock on recursive xmit"),
the PPP xmit path is protected by wrapper functions which disable the
bh already. So it is unnecessary to disable the bh again in the real
xmit path.

Signed-off-by: Gao Feng <gfree.wind@vip.163.com>
Acked-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h>

Fix up affected files that include this signal functionality via sched.h.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

net: make ndo_get_stats64 a void function

The network device operation for reading statistics is only called
in one place, and it ignores the return value. Having a structure
return value is potentially confusing because some future driver could
incorrectly assume that the return value was used.

Fix all drivers with ndo_get_stats64 to have a void function.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

netns: make struct pernet_operations::id unsigned int

Make struct pernet_operations::id unsigned.

There are 2 reasons to do so:

1)
This field is really an index into an zero based array and
thus is unsigned entity. Using negative value is out-of-bound
access by definition.

2)
On x86_64 unsigned 32-bit data which are mixed with pointers
via array indexing or offsets added or subtracted to pointers
are preffered to signed 32-bit data.

"int" being used as an array index needs to be sign-extended
to 64-bit before being used.

void f(long *p, int i)
{
g(p[i]);
}

roughly translates to

movsx rsi, esi
mov rdi, [rsi+...]
call g

MOVSX is 3 byte instruction which isn't necessary if the variable is
unsigned because x86_64 is zero extending by default.

Now, there is net_generic() function which, you guessed it right, uses
"int" as an array index:

static inline void *net_generic(const struct net *net, int id)
{
...
ptr = ng->ptr[id - 1];
...
}

And this function is used a lot, so those sign extensions add up.

Patch snipes ~1730 bytes on allyesconfig kernel (without all junk
messing with code generation):

add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)

Unfortunately some functions actually grow bigger.
This is a semmingly random artefact of code generation with register
allocator being used differently. gcc decides that some variable
needs to live in new r8+ registers and every access now requires REX
prefix. Or it is shifted into r12, so [r12+0] addressing mode has to be
used which is longer than [r8]

However, overall balance is in negative direction:

add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)
function old new delta
nfsd4_lock 3886 3959 +73
tipc_link_build_proto_msg 1096 1140 +44
mac80211_hwsim_new_radio 2776 2808 +32
tipc_mon_rcv 1032 1058 +26
svcauth_gss_legacy_init 1413 1429 +16
tipc_bcbase_select_primary 379 392 +13
nfsd4_exchange_id 1247 1260 +13
nfsd4_setclientid_confirm 782 793 +11
...
put_client_renew_locked 494 480 -14
ip_set_sockfn_get 730 716 -14
geneve_sock_add 829 813 -16
nfsd4_sequence_done 721 703 -18
nlmclnt_lookup_host 708 686 -22
nfsd4_lockt 1085 1063 -22
nfs_get_client 1077 1050 -27
tcf_bpf_init 1106 1076 -30
nfsd4_encode_fattr 5997 5930 -67
Total: Before=154856051, After=154854321, chg -0.00%

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: declare PPP devices as LLTX

ppp_xmit_process() already locks the xmit path. If HARD_TX_LOCK() tries
to hold the _xmit_lock we can get lock inversion.

[ 973.726130] ======================================================
[ 973.727311] [ INFO: possible circular locking dependency detected ]
[ 973.728546] 4.8.0-rc2 #1 Tainted: G O
[ 973.728986] -------------------------------------------------------
[ 973.728986] accel-pppd/1806 is trying to acquire lock:
[ 973.728986] (&qdisc_xmit_lock_key){+.-...}, at: [<ffffffff8146f6fe>] sch_direct_xmit+0x8d/0x221
[ 973.728986]
[ 973.728986] but task is already holding lock:
[ 973.728986] (l2tp_sock){+.-...}, at: [<ffffffffa0202c4a>] l2tp_xmit_skb+0x1e8/0x5d7 [l2tp_core]
[ 973.728986]
[ 973.728986] which lock already depends on the new lock.
[ 973.728986]
[ 973.728986]
[ 973.728986] the existing dependency chain (in reverse order) is:
[ 973.728986]
-> #3 (l2tp_sock){+.-...}:
[ 973.728986] [<ffffffff810b3130>] lock_acquire+0x150/0x217
[ 973.728986] [<ffffffff815752f4>] _raw_spin_lock+0x2d/0x3c
[ 973.728986] [<ffffffffa0202c4a>] l2tp_xmit_skb+0x1e8/0x5d7 [l2tp_core]
[ 973.728986] [<ffffffffa01b2466>] pppol2tp_xmit+0x1f2/0x25e [l2tp_ppp]
[ 973.728986] [<ffffffffa0184f59>] ppp_channel_push+0xb5/0x14a [ppp_generic]
[ 973.728986] [<ffffffffa01853ed>] ppp_write+0x104/0x11c [ppp_generic]
[ 973.728986] [<ffffffff811b2ec6>] __vfs_write+0x56/0x120
[ 973.728986] [<ffffffff811b3f4c>] vfs_write+0xbd/0x11b
[ 973.728986] [<ffffffff811b4cb2>] SyS_write+0x5e/0x96
[ 973.728986] [<ffffffff81575ba5>] entry_SYSCALL_64_fastpath+0x18/0xa8
[ 973.728986]
-> #2 (&(&pch->downl)->rlock){+.-...}:
[ 973.728986] [<ffffffff810b3130>] lock_acquire+0x150/0x217
[ 973.728986] [<ffffffff81575334>] _raw_spin_lock_bh+0x31/0x40
[ 973.728986] [<ffffffffa01808e2>] ppp_push+0xa7/0x82d [ppp_generic]
[ 973.728986] [<ffffffffa0184675>] __ppp_xmit_process+0x48/0x877 [ppp_generic]
[ 973.728986] [<ffffffffa018505b>] ppp_xmit_process+0x4b/0xaf [ppp_generic]
[ 973.728986] [<ffffffffa01853f7>] ppp_write+0x10e/0x11c [ppp_generic]
[ 973.728986] [<ffffffff811b2ec6>] __vfs_write+0x56/0x120
[ 973.728986] [<ffffffff811b3f4c>] vfs_write+0xbd/0x11b
[ 973.728986] [<ffffffff811b4cb2>] SyS_write+0x5e/0x96
[ 973.728986] [<ffffffff81575ba5>] entry_SYSCALL_64_fastpath+0x18/0xa8
[ 973.728986]
-> #1 (&(&ppp->wlock)->rlock){+.-...}:
[ 973.728986] [<ffffffff810b3130>] lock_acquire+0x150/0x217
[ 973.728986] [<ffffffff81575334>] _raw_spin_lock_bh+0x31/0x40
[ 973.728986] [<ffffffffa0184654>] __ppp_xmit_process+0x27/0x877 [ppp_generic]
[ 973.728986] [<ffffffffa018505b>] ppp_xmit_process+0x4b/0xaf [ppp_generic]
[ 973.728986] [<ffffffffa01852da>] ppp_start_xmit+0x21b/0x22a [ppp_generic]
[ 973.728986] [<ffffffff8143f767>] dev_hard_start_xmit+0x1a9/0x43d
[ 973.728986] [<ffffffff8146f747>] sch_direct_xmit+0xd6/0x221
[ 973.728986] [<ffffffff814401e4>] __dev_queue_xmit+0x62a/0x912
[ 973.728986] [<ffffffff814404d7>] dev_queue_xmit+0xb/0xd
[ 973.728986] [<ffffffff81449978>] neigh_direct_output+0xc/0xe
[ 973.728986] [<ffffffff8150e62b>] ip6_finish_output2+0x5a9/0x623
[ 973.728986] [<ffffffff81512128>] ip6_output+0x15e/0x16a
[ 973.728986] [<ffffffff8153ef86>] dst_output+0x76/0x7f
[ 973.728986] [<ffffffff8153f737>] mld_sendpack+0x335/0x404
[ 973.728986] [<ffffffff81541c61>] mld_send_initial_cr.part.21+0x99/0xa2
[ 973.728986] [<ffffffff8154441d>] ipv6_mc_dad_complete+0x42/0x71
[ 973.728986] [<ffffffff8151c4bd>] addrconf_dad_completed+0x1cf/0x2ea
[ 973.728986] [<ffffffff8151e4fa>] addrconf_dad_work+0x453/0x520
[ 973.728986] [<ffffffff8107a393>] process_one_work+0x365/0x6f0
[ 973.728986] [<ffffffff8107aecd>] worker_thread+0x2de/0x421
[ 973.728986] [<ffffffff810816fb>] kthread+0x121/0x130
[ 973.728986] [<ffffffff81575dbf>] ret_from_fork+0x1f/0x40
[ 973.728986]
-> #0 (&qdisc_xmit_lock_key){+.-...}:
[ 973.728986] [<ffffffff810b28d6>] __lock_acquire+0x1118/0x1483
[ 973.728986] [<ffffffff810b3130>] lock_acquire+0x150/0x217
[ 973.728986] [<ffffffff815752f4>] _raw_spin_lock+0x2d/0x3c
[ 973.728986] [<ffffffff8146f6fe>] sch_direct_xmit+0x8d/0x221
[ 973.728986] [<ffffffff814401e4>] __dev_queue_xmit+0x62a/0x912
[ 973.728986] [<ffffffff814404d7>] dev_queue_xmit+0xb/0xd
[ 973.728986] [<ffffffff81449978>] neigh_direct_output+0xc/0xe
[ 973.728986] [<ffffffff81487811>] ip_finish_output2+0x5db/0x609
[ 973.728986] [<ffffffff81489590>] ip_finish_output+0x152/0x15e
[ 973.728986] [<ffffffff8148a0d4>] ip_output+0x8c/0x96
[ 973.728986] [<ffffffff81489652>] ip_local_out+0x41/0x4a
[ 973.728986] [<ffffffff81489e7d>] ip_queue_xmit+0x5a5/0x609
[ 973.728986] [<ffffffffa0202fe4>] l2tp_xmit_skb+0x582/0x5d7 [l2tp_core]
[ 973.728986] [<ffffffffa01b2466>] pppol2tp_xmit+0x1f2/0x25e [l2tp_ppp]
[ 973.728986] [<ffffffffa0184f59>] ppp_channel_push+0xb5/0x14a [ppp_generic]
[ 973.728986] [<ffffffffa01853ed>] ppp_write+0x104/0x11c [ppp_generic]
[ 973.728986] [<ffffffff811b2ec6>] __vfs_write+0x56/0x120
[ 973.728986] [<ffffffff811b3f4c>] vfs_write+0xbd/0x11b
[ 973.728986] [<ffffffff811b4cb2>] SyS_write+0x5e/0x96
[ 973.728986] [<ffffffff81575ba5>] entry_SYSCALL_64_fastpath+0x18/0xa8
[ 973.728986]
[ 973.728986] other info that might help us debug this:
[ 973.728986]
[ 973.728986] Chain exists of:
&qdisc_xmit_lock_key --> &(&pch->downl)->rlock --> l2tp_sock

[ 973.728986] Possible unsafe locking scenario:
[ 973.728986]
[ 973.728986] CPU0 CPU1
[ 973.728986] ---- ----
[ 973.728986] lock(l2tp_sock);
[ 973.728986] lock(&(&pch->downl)->rlock);
[ 973.728986] lock(l2tp_sock);
[ 973.728986] lock(&qdisc_xmit_lock_key);
[ 973.728986]
[ 973.728986] *** DEADLOCK ***
[ 973.728986]
[ 973.728986] 6 locks held by accel-pppd/1806:
[ 973.728986] #0: (&(&pch->downl)->rlock){+.-...}, at: [<ffffffffa0184efa>] ppp_channel_push+0x56/0x14a [ppp_generic]
[ 973.728986] #1: (l2tp_sock){+.-...}, at: [<ffffffffa0202c4a>] l2tp_xmit_skb+0x1e8/0x5d7 [l2tp_core]
[ 973.728986] #2: (rcu_read_lock){......}, at: [<ffffffff81486981>] rcu_lock_acquire+0x0/0x20
[ 973.728986] #3: (rcu_read_lock_bh){......}, at: [<ffffffff81486981>] rcu_lock_acquire+0x0/0x20
[ 973.728986] #4: (rcu_read_lock_bh){......}, at: [<ffffffff814340e3>] rcu_lock_acquire+0x0/0x20
[ 973.728986] #5: (dev->qdisc_running_key ?: &qdisc_running_key#2){+.....}, at: [<ffffffff8144011e>] __dev_queue_xmit+0x564/0x912
[ 973.728986]
[ 973.728986] stack backtrace:
[ 973.728986] CPU: 2 PID: 1806 Comm: accel-pppd Tainted: G O 4.8.0-rc2 #1
[ 973.728986] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
[ 973.728986] ffff7fffffffffff ffff88003436f850 ffffffff812a20f4 ffffffff82156e30
[ 973.728986] ffffffff82156920 ffff88003436f890 ffffffff8115c759 ffff88003344ae00
[ 973.728986] ffff88003344b5c0 0000000000000002 0000000000000006 ffff88003344b5e8
[ 973.728986] Call Trace:
[ 973.728986] [<ffffffff812a20f4>] dump_stack+0x67/0x90
[ 973.728986] [<ffffffff8115c759>] print_circular_bug+0x22e/0x23c
[ 973.728986] [<ffffffff810b28d6>] __lock_acquire+0x1118/0x1483
[ 973.728986] [<ffffffff810b3130>] lock_acquire+0x150/0x217
[ 973.728986] [<ffffffff810b3130>] ? lock_acquire+0x150/0x217
[ 973.728986] [<ffffffff8146f6fe>] ? sch_direct_xmit+0x8d/0x221
[ 973.728986] [<ffffffff815752f4>] _raw_spin_lock+0x2d/0x3c
[ 973.728986] [<ffffffff8146f6fe>] ? sch_direct_xmit+0x8d/0x221
[ 973.728986] [<ffffffff8146f6fe>] sch_direct_xmit+0x8d/0x221
[ 973.728986] [<ffffffff814401e4>] __dev_queue_xmit+0x62a/0x912
[ 973.728986] [<ffffffff814404d7>] dev_queue_xmit+0xb/0xd
[ 973.728986] [<ffffffff81449978>] neigh_direct_output+0xc/0xe
[ 973.728986] [<ffffffff81487811>] ip_finish_output2+0x5db/0x609
[ 973.728986] [<ffffffff81486853>] ? dst_mtu+0x29/0x2e
[ 973.728986] [<ffffffff81489590>] ip_finish_output+0x152/0x15e
[ 973.728986] [<ffffffff8148a0bc>] ? ip_output+0x74/0x96
[ 973.728986] [<ffffffff8148a0d4>] ip_output+0x8c/0x96
[ 973.728986] [<ffffffff81489652>] ip_local_out+0x41/0x4a
[ 973.728986] [<ffffffff81489e7d>] ip_queue_xmit+0x5a5/0x609
[ 973.728986] [<ffffffff814c559e>] ? udp_set_csum+0x207/0x21e
[ 973.728986] [<ffffffffa0202fe4>] l2tp_xmit_skb+0x582/0x5d7 [l2tp_core]
[ 973.728986] [<ffffffffa01b2466>] pppol2tp_xmit+0x1f2/0x25e [l2tp_ppp]
[ 973.728986] [<ffffffffa0184f59>] ppp_channel_push+0xb5/0x14a [ppp_generic]
[ 973.728986] [<ffffffffa01853ed>] ppp_write+0x104/0x11c [ppp_generic]
[ 973.728986] [<ffffffff811b2ec6>] __vfs_write+0x56/0x120
[ 973.728986] [<ffffffff8124c11d>] ? fsnotify_perm+0x27/0x95
[ 973.728986] [<ffffffff8124d41d>] ? security_file_permission+0x4d/0x54
[ 973.728986] [<ffffffff811b3f4c>] vfs_write+0xbd/0x11b
[ 973.728986] [<ffffffff811b4cb2>] SyS_write+0x5e/0x96
[ 973.728986] [<ffffffff81575ba5>] entry_SYSCALL_64_fastpath+0x18/0xa8
[ 973.728986] [<ffffffff810ae0fa>] ? trace_hardirqs_off_caller+0x121/0x12f

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: avoid dealock on recursive xmit

In case of misconfiguration, a virtual PPP channel might send packets
back to their parent PPP interface. This typically happens in
misconfigured L2TP setups, where PPP's peer IP address is set with the
IP of the L2TP peer.
When that happens the system hangs due to PPP trying to recursively
lock its xmit path.

[ 243.332155] BUG: spinlock recursion on CPU#1, accel-pppd/926
[ 243.333272] lock: 0xffff880033d90f18, .magic: dead4ead, .owner: accel-pppd/926, .owner_cpu: 1
[ 243.334859] CPU: 1 PID: 926 Comm: accel-pppd Not tainted 4.8.0-rc2 #1
[ 243.336010] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
[ 243.336018] ffff7fffffffffff ffff8800319a77a0 ffffffff8128de85 ffff880033d90f18
[ 243.336018] ffff880033ad8000 ffff8800319a77d8 ffffffff810ad7c0 ffffffff0000039e
[ 243.336018] ffff880033d90f18 ffff880033d90f60 ffff880033d90f18 ffff880033d90f28
[ 243.336018] Call Trace:
[ 243.336018] [<ffffffff8128de85>] dump_stack+0x4f/0x65
[ 243.336018] [<ffffffff810ad7c0>] spin_dump+0xe1/0xeb
[ 243.336018] [<ffffffff810ad7f0>] spin_bug+0x26/0x28
[ 243.336018] [<ffffffff810ad8b9>] do_raw_spin_lock+0x5c/0x160
[ 243.336018] [<ffffffff815522aa>] _raw_spin_lock_bh+0x35/0x3c
[ 243.336018] [<ffffffffa01a88e2>] ? ppp_push+0xa7/0x82d [ppp_generic]
[ 243.336018] [<ffffffffa01a88e2>] ppp_push+0xa7/0x82d [ppp_generic]
[ 243.336018] [<ffffffff810adada>] ? do_raw_spin_unlock+0xc2/0xcc
[ 243.336018] [<ffffffff81084962>] ? preempt_count_sub+0x13/0xc7
[ 243.336018] [<ffffffff81552438>] ? _raw_spin_unlock_irqrestore+0x34/0x49
[ 243.336018] [<ffffffffa01ac657>] ppp_xmit_process+0x48/0x877 [ppp_generic]
[ 243.336018] [<ffffffff81084962>] ? preempt_count_sub+0x13/0xc7
[ 243.336018] [<ffffffff81408cd3>] ? skb_queue_tail+0x71/0x7c
[ 243.336018] [<ffffffffa01ad1c5>] ppp_start_xmit+0x21b/0x22a [ppp_generic]
[ 243.336018] [<ffffffff81426af1>] dev_hard_start_xmit+0x15e/0x32c
[ 243.336018] [<ffffffff81454ed7>] sch_direct_xmit+0xd6/0x221
[ 243.336018] [<ffffffff814273a8>] __dev_queue_xmit+0x52a/0x820
[ 243.336018] [<ffffffff814276a9>] dev_queue_xmit+0xb/0xd
[ 243.336018] [<ffffffff81430a3c>] neigh_direct_output+0xc/0xe
[ 243.336018] [<ffffffff8146b5d7>] ip_finish_output2+0x4d2/0x548
[ 243.336018] [<ffffffff8146a8e6>] ? dst_mtu+0x29/0x2e
[ 243.336018] [<ffffffff8146d49c>] ip_finish_output+0x152/0x15e
[ 243.336018] [<ffffffff8146df84>] ? ip_output+0x74/0x96
[ 243.336018] [<ffffffff8146df9c>] ip_output+0x8c/0x96
[ 243.336018] [<ffffffff8146d55e>] ip_local_out+0x41/0x4a
[ 243.336018] [<ffffffff8146dd15>] ip_queue_xmit+0x531/0x5c5
[ 243.336018] [<ffffffff814a82cd>] ? udp_set_csum+0x207/0x21e
[ 243.336018] [<ffffffffa01f2f04>] l2tp_xmit_skb+0x582/0x5d7 [l2tp_core]
[ 243.336018] [<ffffffffa01ea458>] pppol2tp_xmit+0x1eb/0x257 [l2tp_ppp]
[ 243.336018] [<ffffffffa01acf17>] ppp_channel_push+0x91/0x102 [ppp_generic]
[ 243.336018] [<ffffffffa01ad2d8>] ppp_write+0x104/0x11c [ppp_generic]
[ 243.336018] [<ffffffff811a3c1e>] __vfs_write+0x56/0x120
[ 243.336018] [<ffffffff81239801>] ? fsnotify_perm+0x27/0x95
[ 243.336018] [<ffffffff8123ab01>] ? security_file_permission+0x4d/0x54
[ 243.336018] [<ffffffff811a4ca4>] vfs_write+0xbd/0x11b
[ 243.336018] [<ffffffff811a5a0a>] SyS_write+0x5e/0x96
[ 243.336018] [<ffffffff81552a1b>] entry_SYSCALL_64_fastpath+0x13/0x94

The main entry points for sending packets over a PPP unit are the
.write() and .ndo_start_xmit() callbacks (simplified view):

.write(unit fd) or .ndo_start_xmit()
\
CALL ppp_xmit_process()
\
LOCK unit's xmit path (ppp->wlock)
|
CALL ppp_push()
\
LOCK channel's xmit path (chan->downl)
|
CALL lower layer's .start_xmit() callback
\
... might recursively call .ndo_start_xmit() ...
/
RETURN from .start_xmit()
|
UNLOCK channel's xmit path
/
RETURN from ppp_push()
|
UNLOCK unit's xmit path
/
RETURN from ppp_xmit_process()

Packets can also be directly sent on channels (e.g. LCP packets):

.write(channel fd) or ppp_output_wakeup()
\
CALL ppp_channel_push()
\
LOCK channel's xmit path (chan->downl)
|
CALL lower layer's .start_xmit() callback
\
... might call .ndo_start_xmit() ...
/
RETURN from .start_xmit()
|
UNLOCK channel's xmit path
/
RETURN from ppp_channel_push()

Key points about the lower layer's .start_xmit() callback:

* It can be called directly by a channel fd .write() or by
ppp_output_wakeup() or indirectly by a unit fd .write() or by
.ndo_start_xmit().

* In any case, it's always called with chan->downl held.

* It might route the packet back to its parent unit using
.ndo_start_xmit() as entry point.

This patch detects and breaks recursion in ppp_xmit_process(). This
function is a good candidate for the task because it's called early
enough after .ndo_start_xmit(), it's always part of the recursion
loop and it's on the path of whatever entry point is used to send
a packet on a PPP unit.

Recursion detection is done using the per-cpu ppp_xmit_recursion
variable.

Since ppp_channel_push() too locks the channel's xmit path and calls
the lower layer's .start_xmit() callback, we need to also increment
ppp_xmit_recursion there. However there's no need to check for
recursion, as it's out of the recursion loop.

Reported-by: Feng Gao <gfree.wind@gmail.com>
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: build ifname using unit identifier for rtnl based devices

Userspace programs generally need to know the name of the ppp devices
they create. Both ioctl and rtnl interfaces use the ppp<suffix> sheme
to name them. But although the suffix used by the ioctl interface can
be known by userspace (it's the PPP unit identifier returned by the
PPPIOCGUNIT ioctl), the one used by the rtnl is only known by the
kernel.

This patch brings more consistency between ioctl and rtnl based ppp
devices by generating device names using the PPP unit identifer as
suffix in both cases. This way, userspace can always infer the name of
the devices they create.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: defer netns reference release for ppp channel

Matt reported that we have a NULL pointer dereference
in ppp_pernet() from ppp_connect_channel(),
i.e. pch->chan_net is NULL.

This is due to that a parallel ppp_unregister_channel()
could happen while we are in ppp_connect_channel(), during
which pch->chan_net set to NULL. Since we need a reference
to net per channel, it makes sense to sync the refcnt
with the life time of the channel, therefore we should
release this reference when we destroy it.

Fixes: 1f461dcdd296 ("ppp: take reference on channels netns")
Reported-by: Matt Bennett <Matt.Bennett@alliedtelesis.co.nz>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linux-ppp@vger.kernel.org
Cc: Guillaume Nault <g.nault@alphalink.fr>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: add netdev_lockdep_set_classes() helper

It is time to add netdev_lockdep_set_classes() helper
so that lockdep annotations per device type are easier to manage.

This removes a lot of copies and missing annotations.

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

net_sched: transform qdisc running bit into a seqcount

Instead of using a single bit (__QDISC___STATE_RUNNING)
in sch->__state, use a seqcount.

This adds lockdep support, but more importantly it will allow us
to sample qdisc/class statistics without having to grab qdisc root lock.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: add rtnetlink device creation support

Define PPP device handler for use with rtnetlink.
The only PPP specific attribute is IFLA_PPP_DEV_FD. It is mandatory and
contains the file descriptor of the associated /dev/ppp instance (the
file descriptor which would have been used for ioctl(PPPIOCNEWUNIT) in
the ioctl-based API). The PPP device is removed when this file
descriptor is released (same behaviour as with ioctl based PPP
devices).

PPP devices created with the rtnetlink API behave like the ones created
with ioctl(PPPIOCNEWUNIT). In particular existing ioctls work the same
way, no matter how the PPP device was created.
The rtnl callbacks are also assigned to ioctl based PPP devices. This
way, rtnl messages have the same effect on any PPP devices.
The immediate effect is that all PPP devices, even ioctl-based
ones, can now be removed with "ip link del".

A minor difference still exists between ioctl and rtnl based PPP
interfaces: in the device name, the number following the "ppp" prefix
corresponds to the PPP unit number for ioctl based devices, while it is
just an unrelated incrementing index for rtnl ones.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: define reusable device creation functions

Move PPP device initialisation and registration out of
ppp_create_interface().
This prepares code for device registration with rtnetlink.

While there, simplify the prototype of ppp_create_interface():

* Since ppp_dev_configure() takes care of setting file->private_data,
there's no need to return a ppp structure to ppp_unattached_ioctl()
anymore.

* The unit parameter is made read/write so that ppp_create_interface()
can tell which unit number has been assigned.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: take reference on channels netns

Let channels hold a reference on their network namespace.
Some channel types, like ppp_async and ppp_synctty, can have their
userspace controller running in a different namespace. Therefore they
can't rely on them to preclude their netns from being removed from
under them.

==================================================================
BUG: KASAN: use-after-free in ppp_unregister_channel+0x372/0x3a0 at
addr ffff880064e217e0
Read of size 8 by task syz-executor/11581
=============================================================================
BUG net_namespace (Not tainted): kasan: bad access detected
-----------------------------------------------------------------------------

Disabling lock debugging due to kernel taint
INFO: Allocated in copy_net_ns+0x6b/0x1a0 age=92569 cpu=3 pid=6906
[< none >] ___slab_alloc+0x4c7/0x500 kernel/mm/slub.c:2440
[< none >] __slab_alloc+0x4c/0x90 kernel/mm/slub.c:2469
[< inline >] slab_alloc_node kernel/mm/slub.c:2532
[< inline >] slab_alloc kernel/mm/slub.c:2574
[< none >] kmem_cache_alloc+0x23a/0x2b0 kernel/mm/slub.c:2579
[< inline >] kmem_cache_zalloc kernel/include/linux/slab.h:597
[< inline >] net_alloc kernel/net/core/net_namespace.c:325
[< none >] copy_net_ns+0x6b/0x1a0 kernel/net/core/net_namespace.c:360
[< none >] create_new_namespaces+0x2f6/0x610 kernel/kernel/nsproxy.c:95
[< none >] copy_namespaces+0x297/0x320 kernel/kernel/nsproxy.c:150
[< none >] copy_process.part.35+0x1bf4/0x5760 kernel/kernel/fork.c:1451
[< inline >] copy_process kernel/kernel/fork.c:1274
[< none >] _do_fork+0x1bc/0xcb0 kernel/kernel/fork.c:1723
[< inline >] SYSC_clone kernel/kernel/fork.c:1832
[< none >] SyS_clone+0x37/0x50 kernel/kernel/fork.c:1826
[< none >] entry_SYSCALL_64_fastpath+0x16/0x7a kernel/arch/x86/entry/entry_64.S:185

INFO: Freed in net_drop_ns+0x67/0x80 age=575 cpu=2 pid=2631
[< none >] __slab_free+0x1fc/0x320 kernel/mm/slub.c:2650
[< inline >] slab_free kernel/mm/slub.c:2805
[< none >] kmem_cache_free+0x2a0/0x330 kernel/mm/slub.c:2814
[< inline >] net_free kernel/net/core/net_namespace.c:341
[< none >] net_drop_ns+0x67/0x80 kernel/net/core/net_namespace.c:348
[< none >] cleanup_net+0x4e5/0x600 kernel/net/core/net_namespace.c:448
[< none >] process_one_work+0x794/0x1440 kernel/kernel/workqueue.c:2036
[< none >] worker_thread+0xdb/0xfc0 kernel/kernel/workqueue.c:2170
[< none >] kthread+0x23f/0x2d0 kernel/drivers/block/aoe/aoecmd.c:1303
[< none >] ret_from_fork+0x3f/0x70 kernel/arch/x86/entry/entry_64.S:468
INFO: Slab 0xffffea0001938800 objects=3 used=0 fp=0xffff880064e20000
flags=0x5fffc0000004080
INFO: Object 0xffff880064e20000 @offset=0 fp=0xffff880064e24200

CPU: 1 PID: 11581 Comm: syz-executor Tainted: G B 4.4.0+
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.8.2-0-g33fbe13 by qemu-project.org 04/01/2014
00000000ffffffff ffff8800662c7790 ffffffff8292049d ffff88003e36a300
ffff880064e20000 ffff880064e20000 ffff8800662c77c0 ffffffff816f2054
ffff88003e36a300 ffffea0001938800 ffff880064e20000 0000000000000000
Call Trace:
[< inline >] __dump_stack kernel/lib/dump_stack.c:15
[<ffffffff8292049d>] dump_stack+0x6f/0xa2 kernel/lib/dump_stack.c:50
[<ffffffff816f2054>] print_trailer+0xf4/0x150 kernel/mm/slub.c:654
[<ffffffff816f875f>] object_err+0x2f/0x40 kernel/mm/slub.c:661
[< inline >] print_address_description kernel/mm/kasan/report.c:138
[<ffffffff816fb0c5>] kasan_report_error+0x215/0x530 kernel/mm/kasan/report.c:236
[< inline >] kasan_report kernel/mm/kasan/report.c:259
[<ffffffff816fb4de>] __asan_report_load8_noabort+0x3e/0x40 kernel/mm/kasan/report.c:280
[< inline >] ? ppp_pernet kernel/include/linux/compiler.h:218
[<ffffffff83ad71b2>] ? ppp_unregister_channel+0x372/0x3a0 kernel/drivers/net/ppp/ppp_generic.c:2392
[< inline >] ppp_pernet kernel/include/linux/compiler.h:218
[<ffffffff83ad71b2>] ppp_unregister_channel+0x372/0x3a0 kernel/drivers/net/ppp/ppp_generic.c:2392
[< inline >] ? ppp_pernet kernel/drivers/net/ppp/ppp_generic.c:293
[<ffffffff83ad6f26>] ? ppp_unregister_channel+0xe6/0x3a0 kernel/drivers/net/ppp/ppp_generic.c:2392
[<ffffffff83ae18f3>] ppp_asynctty_close+0xa3/0x130 kernel/drivers/net/ppp/ppp_async.c:241
[<ffffffff83ae1850>] ? async_lcp_peek+0x5b0/0x5b0 kernel/drivers/net/ppp/ppp_async.c:1000
[<ffffffff82c33239>] tty_ldisc_close.isra.1+0x99/0xe0 kernel/drivers/tty/tty_ldisc.c:478
[<ffffffff82c332c0>] tty_ldisc_kill+0x40/0x170 kernel/drivers/tty/tty_ldisc.c:744
[<ffffffff82c34943>] tty_ldisc_release+0x1b3/0x260 kernel/drivers/tty/tty_ldisc.c:772
[<ffffffff82c1ef21>] tty_release+0xac1/0x13e0 kernel/drivers/tty/tty_io.c:1901
[<ffffffff82c1e460>] ? release_tty+0x320/0x320 kernel/drivers/tty/tty_io.c:1688
[<ffffffff8174de36>] __fput+0x236/0x780 kernel/fs/file_table.c:208
[<ffffffff8174e405>] ____fput+0x15/0x20 kernel/fs/file_table.c:244
[<ffffffff813595ab>] task_work_run+0x16b/0x200 kernel/kernel/task_work.c:115
[< inline >] exit_task_work kernel/include/linux/task_work.h:21
[<ffffffff81307105>] do_exit+0x8b5/0x2c60 kernel/kernel/exit.c:750
[<ffffffff813fdd20>] ? debug_check_no_locks_freed+0x290/0x290 kernel/kernel/locking/lockdep.c:4123
[<ffffffff81306850>] ? mm_update_next_owner+0x6f0/0x6f0 kernel/kernel/exit.c:357
[<ffffffff813215e6>] ? __dequeue_signal+0x136/0x470 kernel/kernel/signal.c:550
[<ffffffff8132067b>] ? recalc_sigpending_tsk+0x13b/0x180 kernel/kernel/signal.c:145
[<ffffffff81309628>] do_group_exit+0x108/0x330 kernel/kernel/exit.c:880
[<ffffffff8132b9d4>] get_signal+0x5e4/0x14f0 kernel/kernel/signal.c:2307
[< inline >] ? kretprobe_table_lock kernel/kernel/kprobes.c:1113
[<ffffffff8151d355>] ? kprobe_flush_task+0xb5/0x450 kernel/kernel/kprobes.c:1158
[<ffffffff8115f7d3>] do_signal+0x83/0x1c90 kernel/arch/x86/kernel/signal.c:712
[<ffffffff8151d2a0>] ? recycle_rp_inst+0x310/0x310 kernel/include/linux/list.h:655
[<ffffffff8115f750>] ? setup_sigcontext+0x780/0x780 kernel/arch/x86/kernel/signal.c:165
[<ffffffff81380864>] ? finish_task_switch+0x424/0x5f0 kernel/kernel/sched/core.c:2692
[< inline >] ? finish_lock_switch kernel/kernel/sched/sched.h:1099
[<ffffffff81380560>] ? finish_task_switch+0x120/0x5f0 kernel/kernel/sched/core.c:2678
[< inline >] ? context_switch kernel/kernel/sched/core.c:2807
[<ffffffff85d794e9>] ? __schedule+0x919/0x1bd0 kernel/kernel/sched/core.c:3283
[<ffffffff81003901>] exit_to_usermode_loop+0xf1/0x1a0 kernel/arch/x86/entry/common.c:247
[< inline >] prepare_exit_to_usermode kernel/arch/x86/entry/common.c:282
[<ffffffff810062ef>] syscall_return_slowpath+0x19f/0x210 kernel/arch/x86/entry/common.c:344
[<ffffffff85d88022>] int_ret_from_sys_call+0x25/0x9f kernel/arch/x86/entry/entry_64.S:281
Memory state around the buggy address:
ffff880064e21680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff880064e21700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff880064e21780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff880064e21800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff880064e21880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Fixes: 273ec51dd7ce ("net: ppp_generic - introduce net-namespace functionality v2")
Reported-by: Baozeng Ding <sploving1@gmail.com>
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: ensure file->private_data can't be overridden

Locking ppp_mutex must be done before dereferencing file->private_data,
otherwise it could be modified before ppp_unattached_ioctl() takes the
lock. This could lead ppp_unattached_ioctl() to override ->private_data,
thus leaking reference to the ppp_file previously pointed to.

v2: lock all ppp_ioctl() instead of just checking private_data in
ppp_unattached_ioctl(), to avoid ambiguous behaviour.

Fixes: f3ff8a4d80e8 ("ppp: push BKL down into the driver")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: release rtnl mutex when interface creation fails

Add missing rtnl_unlock() in the error path of ppp_create_interface().

Fixes: 58a89ecaca53 ("ppp: fix lockdep splat in ppp_dev_uninit()")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: lock ppp->flags in ppp_read() and ppp_poll()

ppp_read() and ppp_poll() can be called concurrently with ppp_ioctl().
In this case, ppp_ioctl() might call ppp_ccp_closed(), which may update
ppp->flags while ppp_read() or ppp_poll() is reading it.
The update done by ppp_ccp_closed() isn't atomic due to the bit mask
operation ('ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP)'), so concurrent
readers might get transient values.
Reading incorrect ppp->flags may disturb the 'ppp->flags & SC_LOOP_TRAFFIC'
test in ppp_read() and ppp_poll(), which in turn can lead to improper
decision on whether the PPP unit file is ready for reading or not.

Since ppp_ccp_closed() is protected by the Rx and Tx locks (with
ppp_lock()), taking the Rx lock is enough for ppp_read() and ppp_poll()
to guarantee that ppp_ccp_closed() won't update ppp->flags
concurrently.

The same reasoning applies to ppp->n_channels. The 'n_channels' field
can also be written to concurrently by ppp_ioctl() (through
ppp_connect_channel() or ppp_disconnect_channel()). These writes aren't
atomic (simple increment/decrement), but are protected by both the Rx
and Tx locks (like in the ppp->flags case). So holding the Rx lock
before reading ppp->n_channels also prevents concurrent writes.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: clarify parsing of user supplied data in ppp_set_compress()

* Split big conditional statement.
* Check (data.length <= CCP_MAX_OPTION_LENGTH) only once.
* Don't read ccp_option[1] if not initialised.

Reading uninitialised ccp_option[1] was harmless, because this could
only happen when data.length was 0 or 1. So even then, we couldn't pass
the (ccp_option[1] < 2 || ccp_option[1] > data.length) test anyway.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: declare ppp devices as enumerated interfaces

Let user space be aware of the naming scheme used by ppp interfaces
(visible in /sys/class/net/<iface>/name_assign_type).

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: define "ppp" device type

Let PPP devices be identified as such in /sys/class/net/<iface>/uevent.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp, slip: Validate VJ compression slot parameters completely

Currently slhc_init() treats out-of-range values of rslots and tslots
as equivalent to 0, except that if tslots is too large it will
dereference a null pointer (CVE-2015-7799).

Add a range-check at the top of the function and make it return an
ERR_PTR() on error instead of NULL. Change the callers accordingly.

Compile-tested only.

Reported-by: 郭永刚 <guoyonggang@360.cn>
References: http://article.gmane.org/gmane.comp.security.oss.general/17908
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: fix lockdep splat in ppp_dev_uninit()

ppp_dev_uninit() locks all_ppp_mutex while under rtnl mutex protection.
ppp_create_interface() must then lock these mutexes in that same order
to avoid possible deadlock.

[ 120.880011] ======================================================
[ 120.880011] [ INFO: possible circular locking dependency detected ]
[ 120.880011] 4.2.0 #1 Not tainted
[ 120.880011] -------------------------------------------------------
[ 120.880011] ppp-apitest/15827 is trying to acquire lock:
[ 120.880011] (&pn->all_ppp_mutex){+.+.+.}, at: [<ffffffffa0145f56>] ppp_dev_uninit+0x64/0xb0 [ppp_generic]
[ 120.880011]
[ 120.880011] but task is already holding lock:
[ 120.880011] (rtnl_mutex){+.+.+.}, at: [<ffffffff812e4255>] rtnl_lock+0x12/0x14
[ 120.880011]
[ 120.880011] which lock already depends on the new lock.
[ 120.880011]
[ 120.880011]
[ 120.880011] the existing dependency chain (in reverse order) is:
[ 120.880011]
[ 120.880011] -> #1 (rtnl_mutex){+.+.+.}:
[ 120.880011] [<ffffffff81073a6f>] lock_acquire+0xcf/0x10e
[ 120.880011] [<ffffffff813ab18a>] mutex_lock_nested+0x56/0x341
[ 120.880011] [<ffffffff812e4255>] rtnl_lock+0x12/0x14
[ 120.880011] [<ffffffff812d9d94>] register_netdev+0x11/0x27
[ 120.880011] [<ffffffffa0147b17>] ppp_ioctl+0x289/0xc98 [ppp_generic]
[ 120.880011] [<ffffffff8113b367>] do_vfs_ioctl+0x4ea/0x532
[ 120.880011] [<ffffffff8113b3fd>] SyS_ioctl+0x4e/0x7d
[ 120.880011] [<ffffffff813ad7d7>] entry_SYSCALL_64_fastpath+0x12/0x6f
[ 120.880011]
[ 120.880011] -> #0 (&pn->all_ppp_mutex){+.+.+.}:
[ 120.880011] [<ffffffff8107334e>] __lock_acquire+0xb07/0xe76
[ 120.880011] [<ffffffff81073a6f>] lock_acquire+0xcf/0x10e
[ 120.880011] [<ffffffff813ab18a>] mutex_lock_nested+0x56/0x341
[ 120.880011] [<ffffffffa0145f56>] ppp_dev_uninit+0x64/0xb0 [ppp_generic]
[ 120.880011] [<ffffffff812d5263>] rollback_registered_many+0x19e/0x252
[ 120.880011] [<ffffffff812d5381>] rollback_registered+0x29/0x38
[ 120.880011] [<ffffffff812d53fa>] unregister_netdevice_queue+0x6a/0x77
[ 120.880011] [<ffffffffa0146a94>] ppp_release+0x42/0x79 [ppp_generic]
[ 120.880011] [<ffffffff8112d9f6>] __fput+0xec/0x192
[ 120.880011] [<ffffffff8112dacc>] ____fput+0x9/0xb
[ 120.880011] [<ffffffff8105447a>] task_work_run+0x66/0x80
[ 120.880011] [<ffffffff81001801>] prepare_exit_to_usermode+0x8c/0xa7
[ 120.880011] [<ffffffff81001900>] syscall_return_slowpath+0xe4/0x104
[ 120.880011] [<ffffffff813ad931>] int_ret_from_sys_call+0x25/0x9f
[ 120.880011]
[ 120.880011] other info that might help us debug this:
[ 120.880011]
[ 120.880011] Possible unsafe locking scenario:
[ 120.880011]
[ 120.880011] CPU0 CPU1
[ 120.880011] ---- ----
[ 120.880011] lock(rtnl_mutex);
[ 120.880011] lock(&pn->all_ppp_mutex);
[ 120.880011] lock(rtnl_mutex);
[ 120.880011] lock(&pn->all_ppp_mutex);
[ 120.880011]
[ 120.880011] *** DEADLOCK ***

Fixes: 8cb775bc0a34 ("ppp: fix device unregistration upon netns deletion")
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: implement x-netns support

Let packets move from one netns to the other at PPP encapsulation and
decapsulation time.

PPP units and channels remain in the netns in which they were
originally created. Only the net_device may move to a different
namespace. Cross netns handling is thus transparent to lower PPP
layers (PPPoE, L2TP, etc.).

PPP devices are automatically unregistered when their netns gets
removed. So read() and poll() on the unit file descriptor will
respectively receive EOF and POLLHUP. Channels aren't affected.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: fix device unregistration upon netns deletion

PPP devices may get automatically unregistered when their network
namespace is getting removed. This happens if the ppp control plane
daemon (e.g. pppd) exits while it is the last user of this namespace.

This leads to several races:

* ppp_exit_net() may destroy the per namespace idr (pn->units_idr)
before all file descriptors were released. Successive ppp_release()
calls may then cleanup PPP devices with ppp_shutdown_interface() and
try to use the already destroyed idr.

* Automatic device unregistration may also happen before the
ppp_release() call for that device gets executed. Once called on
the file owning the device, ppp_release() will then clean it up and
try to unregister it a second time.

To fix these issues, operations defined in ppp_shutdown_interface() are
moved to the PPP device's ndo_uninit() callback. This allows PPP
devices to be properly cleaned up by unregister_netdev() and friends.
So checking for ppp->owner is now an accurate test to decide if a PPP
device should be unregistered.

Setting ppp->owner is done in ppp_create_interface(), before device
registration, in order to avoid unprotected modification of this field.

Finally, ppp_exit_net() now starts by unregistering all remaining PPP
devices to ensure that none will get unregistered after the call to
idr_destroy().

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: call skb_checksum_complete_unset in ppp_receive_frame

Call checksum_complete_unset in PPP receive to discard checksum-complete
value. PPP does not pull checksum for headers and also modifies packet
as in VJ compression.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp_read(): switch to skb_copy_datagram_iter()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

net: ppp: Don't call bpf_prog_create() in ppp_lock

In ppp_ioctl(), bpf_prog_create() is called inside ppp_lock, which
eventually calls vmalloc() and hits BUG_ON() in vmalloc.c. This patch
works around the problem by moving the allocation outside the lock.

The bug was revealed by the recent change in net/core/filter.c, as it
allocates via vmalloc() instead of kmalloc() now.

Reported-and-tested-by: Stefan Seyfried <stefan.seyfried@googlemail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

fix misuses of f_count() in ppp and netlink

we used to check for "nobody else could start doing anything with
that opened file" by checking that refcount was 2 or less - one
for descriptor table and one we'd acquired in fget() on the way to
wherever we are. That was race-prone (somebody else might have
had a reference to descriptor table and do fget() just as we'd
been checking) and it had become flat-out incorrect back when
we switched to fget_light() on those codepaths - unlike fget(),
it doesn't grab an extra reference unless the descriptor table
is shared. The same change allowed a race-free check, though -
we are safe exactly when refcount is less than 2.

It was a long time ago; pre-2.6.12 for ioctl() (the codepath leading
to ppp one) and 2.6.17 for sendmsg() (netlink one). OTOH,
netlink hadn't grown that check until 3.9 and ppp used to live
in drivers/net, not drivers/net/ppp until 3.1. The bug existed
well before that, though, and the same fix used to apply in old
location of file.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

net: better IFF_XMIT_DST_RELEASE support

Testing xmit_more support with netperf and connected UDP sockets,
I found strange dst refcount false sharing.

Current handling of IFF_XMIT_DST_RELEASE is not optimal.

Dropping dst in validate_xmit_skb() is certainly too late in case
packet was queued by cpu X but dequeued by cpu Y

The logical point to take care of drop/force is in __dev_queue_xmit()
before even taking qdisc lock.

As Julian Anastasov pointed out, need for skb_dst() might come from some
packet schedulers or classifiers.

This patch adds new helper to cleanly express needs of various drivers
or qdiscs/classifiers.

Drivers that need skb_dst() in their ndo_start_xmit() should call
following helper in their setup instead of the prior :

dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
->
netif_keep_dst(dev);

Instead of using a single bit, we use two bits, one being
eventually rebuilt in bonding/team drivers.

The other one, is permanent and blocks IFF_XMIT_DST_RELEASE being
rebuilt in bonding/team. Eventually, we could add something
smarter later.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: filter: split 'struct sk_filter' into socket and bpf parts

clean up names related to socket filtering and bpf in the following way:
- everything that deals with sockets keeps 'sk_*' prefix
- everything that is pure BPF is changed to 'bpf_*' prefix

split 'struct sk_filter' into
struct sk_filter {
atomic_t refcnt;
struct rcu_head rcu;
struct bpf_prog *prog;
};
and
struct bpf_prog {
u32 jited:1,
len:31;
struct sock_fprog_kern *orig_prog;
unsigned int (*bpf_func)(const struct sk_buff *skb,
const struct bpf_insn *filter);
union {
struct sock_filter insns[0];
struct bpf_insn insnsi[0];
struct work_struct work;
};
};
so that 'struct bpf_prog' can be used independent of sockets and cleans up
'unattached' bpf use cases

split SK_RUN_FILTER macro into:
SK_RUN_FILTER to be used with 'struct sk_filter *' and
BPF_PROG_RUN to be used with 'struct bpf_prog *'

__sk_filter_release(struct sk_filter *) gains
__bpf_prog_release(struct bpf_prog *) helper function

also perform related renames for the functions that work
with 'struct bpf_prog *', since they're on the same lines:

sk_filter_size -> bpf_prog_size
sk_filter_select_runtime -> bpf_prog_select_runtime
sk_filter_free -> bpf_prog_free
sk_unattached_filter_create -> bpf_prog_create
sk_unattached_filter_destroy -> bpf_prog_destroy
sk_store_orig_filter -> bpf_prog_store_orig_filter
sk_release_orig_filter -> bpf_release_orig_filter
__sk_migrate_filter -> bpf_migrate_filter
__sk_prepare_filter -> bpf_prepare_filter

API for attaching classic BPF to a socket stays the same:
sk_attach_filter(prog, struct sock *)/sk_detach_filter(struct sock *)
and SK_RUN_FILTER(struct sk_filter *, ctx) to execute a program
which is used by sockets, tun, af_packet

API for 'unattached' BPF programs becomes:
bpf_prog_create(struct bpf_prog **)/bpf_prog_destroy(struct bpf_prog *)
and BPF_PROG_RUN(struct bpf_prog *, ctx) to execute a program
which is used by isdn, ppp, team, seccomp, ptp, xt_bpf, cls_bpf, test_bpf

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ppp: fix creating PPP pass and active filters

Commit 568f194e8bd16c353ad50f9ab95d98b20578a39d ("net: ppp: use
sk_unattached_filter api") inadvertently changed the logic when setting
PPP pass and active filters. This applies to both the generic PPP subsystem
implemented by drivers/net/ppp/ppp_generic.c and the ISDN PPP subsystem
implemented by drivers/isdn/i4l/isdn_ppp.c. The original code in ppp_ioctl()
(or isdn_ppp_ioctl(), resp.) handling PPPIOCSPASS and PPPIOCSACTIVE allowed to
remove a pass/active filter previously set by using a filter of length zero.
However, with the new code this is not possible anymore as this case is not
explicitly checked for, which leads to passing NULL as a filter to
sk_unattached_filter_create(). This results in returning EINVAL to the caller.

Additionally, the variables ppp->pass_filter and ppp->active_filter (or
is->pass_filter and is->active_filter, resp.) are not reset to NULL, although
the filters they point to may have been destroyed by
sk_unattached_filter_destroy(), so in this EINVAL case dangling pointers are
left behind (provided the pointers were previously non-NULL).

This patch corrects both problems by checking whether the filter passed is
empty or non-empty, and prevents sk_unattached_filter_create() from being
called in the first case. Moreover, the pointers are always reset to NULL
as soon as sk_unattached_filter_destroy() returns.

Signed-off-by: Christoph Schulz <develop@kristov.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ppp: access ppp->nextseq only if CONFIG_PPP_MULTILINK is defined

Commit d762d038497c9df51c19fcbe69b094b3bf8e5568 resets the counter holding the
next sequence number for multilink PPP fragments to zero whenever the
SC_MULTILINK flag is set. However, this counter only exists if
CONFIG_PPP_MULTILINK is defined. Consequently, the new code has to be enclosed
within #ifdef CONFIG_PPP_MULTILINK ... #endif.

Signed-off-by: Christoph Schulz <develop@kristov.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ppp: reset nextseq counter when enabling SC_MULTILINK

If using a demand-dialled PPP unit for a PPP multilink master, the pppd
daemon needs to reset the sequence counter between two connections. This
allows the daemon to reuse the PPP unit instead of destroying and recreating
it. As there is no API to reset the counter, this patch resets the counter
whenever the SC_MULTILINK flag is set.

Signed-off-by: Christoph Schulz <develop@kristov.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: set name_assign_type in alloc_netdev()

Extend alloc_netdev{,_mq{,s}}() to take name_assign_type as argument, and convert
all users to pass NET_NAME_UNKNOWN.

Coccinelle patch:

@@
expression sizeof_priv, name, setup, txqs, rxqs, count;
@@

(
-alloc_netdev_mqs(sizeof_priv, name, setup, txqs, rxqs)
+alloc_netdev_mqs(sizeof_priv, name, NET_NAME_UNKNOWN, setup, txqs, rxqs)
|
-alloc_netdev_mq(sizeof_priv, name, setup, count)
+alloc_netdev_mq(sizeof_priv, name, NET_NAME_UNKNOWN, setup, count)
|
-alloc_netdev(sizeof_priv, name, setup)
+alloc_netdev(sizeof_priv, name, NET_NAME_UNKNOWN, setup)
)

v9: move comments here from the wrong commit

Signed-off-by: Tom Gundersen <teg@jklm.no>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ppp: don't call sk_chk_filter twice

Commit 568f194e8bd16c353ad50f9ab95d98b20578a39d ("net: ppp: use
sk_unattached_filter api") causes sk_chk_filter() to be called twice when
setting a PPP pass or active filter. This applies to both the generic PPP
subsystem implemented by drivers/net/ppp/ppp_generic.c and the ISDN PPP
subsystem implemented by drivers/isdn/i4l/isdn_ppp.c. The first call is from
within get_filter(). The second one is through the call chain

ppp_ioctl() or isdn_ppp_ioctl()
--> sk_unattached_filter_create()
--> __sk_prepare_filter()
--> sk_chk_filter()

The first call from within get_filter() should be deleted as get_filter() is
called just before calling sk_unattached_filter_create() later on, which
eventually calls sk_chk_filter() anyway.

For 3.15.x, this proposed change is a bugfix rather than a pure optimization as
in that branch, sk_chk_filter() may replace filter codes by other codes which
are not recognized when executing sk_chk_filter() a second time. So with
3.15.x, if sk_chk_filter() is called twice, the second invocation may yield
EINVAL (this depends on the filter codes found in the filter to be set, but
because the replacement is done for frequently used codes, this is almost
always the case). The net effect is that setting pass and/or active PPP filters
does not work anymore, since sk_unattached_filter_create() always returns
EINVAL due to the second call to sk_chk_filter(), regardless whether the filter
was originally sane or not.

Signed-off-by: Christoph Schulz <develop@kristov.de>
Acked-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: filter: let unattached filters use sock_fprog_kern

The sk_unattached_filter_create() API is used by BPF filters that
are not directly attached or related to sockets, and are used in
team, ptp, xt_bpf, cls_bpf, etc. As such all users do their own
internal managment of obtaining filter blocks and thus already
have them in kernel memory and set up before calling into
sk_unattached_filter_create(). As a result, due to __user annotation
in sock_fprog, sparse triggers false positives (incorrect type in
assignment [different address space]) when filters are set up before
passing them to sk_unattached_filter_create(). Therefore, let
sk_unattached_filter_create() API use sock_fprog_kern to overcome
this issue.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ppp: use sk_unattached_filter api

For the ppp driver, there are currently two open-coded BPF filters in use,
that is, pass_filter and active_filter. Migrate both to make proper use
of sk_unattached_filter_{create,destroy} API so that the actual BPF code
is decoupled from direct access, and filters can be jited as a side-effect
by the internal filter compiler.

Joint work with Alexei Starovoitov.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linux-ppp@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: convert to idr_alloc()

Convert to the much saner new idr interface.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ppp: set qdisc_tx_busylock to avoid LOCKDEP splat

If a qdisc is installed on a ppp device, its possible to get
a lockdep splat under stress, because nested dev_queue_xmit() can
lock busylock a second time (on a different device, so its a false
positive)

Avoid this problem using a distinct lock_class_key for ppp
devices.

Reported-by: Yanko Kaneti <yaneti@declera.com>
Tested-by: Yanko Kaneti <yaneti@declera.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Add skb_unclone() helper function.

This function will be used in next GRE_GSO patch. This patch does
not change any functionality.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Eric Dumazet <edumazet@google.com>

ppp: make ppp_get_stats64 static

This was picked up by sparse.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: add 64 bit stats

Add 64 bit stats to ppp driver. The 64 bit stats include tx_bytes,
rx_bytes, tx_packets and rx_packets. Other stats are still 32 bit.
The 64 bit stats can be retrieved via the ndo_get_stats operation. The
SIOCGPPPSTATS ioctl is still 32 bit stats only.

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

ppp: avoid false drop_monitor false positives

Call consume_skb() in place of kfree_skb() were appropriate.

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

ppp: Fix race condition with queue start/stop

Commit e675f0cc9a872fd152edc0c77acfed19bf28b81e ("ppp: Don't stop and
restart queue on every TX packet") introduced a race condition which
could leave the net queue stopped even when the channel is no longer
busy. By calling netif_stop_queue() from ppp_start_xmit(), based on the
return value from ppp_xmit_process() but *after* all the locks have been
dropped, we could potentially do so *after* the channel has actually
finished transmitting and attempted to re-wake the queue.

Fix this by moving the netif_stop_queue() into ppp_xmit_process() under
the xmit lock. I hadn't done this previously, because it gets called
from other places than ppp_start_xmit(). But I now think it's the better
option. The net queue *should* be stopped if the channel becomes
congested due to writes from pppd, anyway.

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

ppp: Don't stop and restart queue on every TX packet

For every transmitted packet, ppp_start_xmit() will stop the netdev
queue and then, if appropriate, restart it. This causes the TX softirq
to run, entirely gratuitously.

This is "only" a waste of CPU time in the normal case, but it's actively
harmful when the PPP device is a TEQL slave — the wakeup will cause the
offending device to receive the next TX packet from the TEQL queue, when
it *should* have gone to the next slave in the list. We end up seeing
large bursts of packets on just *one* slave device, rather than using
the full available bandwidth over all slaves.

This patch fixes the problem by *not* unconditionally stopping the queue
in ppp_start_xmit(). It adds a return value from ppp_xmit_process()
which indicates whether the queue should be stopped or not.

It *doesn't* remove the call to netif_wake_queue() from
ppp_xmit_process(), because other code paths (especially from
ppp_output_wakeup()) need it there and it's messy to push it out to the
other callers to do it based on the return value. So we leave it in
place — it's a no-op in the case where the queue wasn't stopped, so it's
harmless in the TX path.

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

ppp: Move ioctl definitions from if_ppp.h to new ppp-ioctl.h

This moves the definitions of the ioctls, constants and structures
relating to the ppp_generic interface to userspace out from if_ppp.h
to a new file, ppp-ioctl.h. The new file has my copyright since I
designed and implemented the ppp_generic interface in the late 1990s.
None of the contents of this file comes from the original if_ppp.h
published by Carnegie Mellon University.

Of the remainder of if_ppp.h, only the PPP_MTU definition was being
used, and this replaces the uses of it with PPP_MRU (which is identical).
Therefore, this replaces the entire file with the single line

#include <linux/ppp-ioctl.h>

which clearly doesn't contain any CMU code. Thus I have removed the
CMU copyright notice with its problematic advertising clause, and in
fact since it's only one trivial line I have not added any other
copyright notice.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: fix 'ppp_mp_reconstruct bad seq' errors

This patch fixes a (mostly cosmetic) bug introduced by the patch
'ppp: Use SKB queue abstraction interfaces in fragment processing'
found here: http://www.spinics.net/lists/netdev/msg153312.html

The above patch rewrote and moved the code responsible for cleaning
up discarded fragments but the new code does not catch every case
where this is necessary. This results in some discarded fragments
remaining in the queue, and triggering a 'bad seq' error on the
subsequent call to ppp_mp_reconstruct. Fragments are discarded
whenever other fragments of the same frame have been lost.
This can generate a lot of unwanted and misleading log messages.

This patch also adds additional detail to the debug logging to
make it clearer which fragments were lost and which other fragments
were discarded as a result of losses. (Run pppd with 'kdebug 1'
option to enable debug logging.)

Signed-off-by: Ben McKeegan <ben@netservers.co.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: fix truesize underestimation

When building frag_list, head truesize should be sum of all frag
truesize.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ppp: Move the PPP drivers

Move the PPP drivers into drivers/net/ppp/ and make the
necessary Kconfig and Makefile changes.

CC: Paul Mackerras <paulus@samba.org>
CC: Frank Cusack <fcusack@fcusack.com>
CC: Michal Ostrowski <mostrows@speakeasy.net>
CC: Michal Ostrowski <mostrows@earthlink.net>
CC: Dmitry Kozlov <xeb@mail.ru>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>