netfilter: ctnetlink: fix filtering for zone 0

previously filtering for the default zone would actually skip the zone
filter and flush all zones.

Fixes: eff3c558bb7e ("netfilter: ctnetlink: support filtering by zone")
Reported-by: Ilya Maximets <i.maximets@ovn.org>
Closes: https://lore.kernel.org/netdev/2032238f-31ac-4106-8f22-522e76df5a12@ovn.org/
Signed-off-by: Felix Huettner <felix.huettner@mail.schwarz>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: support filtering by zone

conntrack zones are heavily used by tools like openvswitch to run
multiple virtual "routers" on a single machine. In this context each
conntrack zone matches to a single router, thereby preventing
overlapping IPs from becoming issues.
In these systems it is common to operate on all conntrack entries of a
given zone, e.g. to delete them when a router is deleted. Previously this
required these tools to dump the full conntrack table and filter out the
relevant entries in userspace potentially causing performance issues.

To do this we reuse the existing CTA_ZONE attribute. This was previous
parsed but not used during dump and flush requests. Now if CTA_ZONE is
set we filter these operations based on the provided zone.
However this means that users that previously passed CTA_ZONE will
experience a difference in functionality.

Alternatively CTA_FILTER could have been used for the same
functionality. However it is not yet supported during flush requests and
is only available when using AF_INET or AF_INET6.

Co-developed-by: Luca Czesla <luca.czesla@mail.schwarz>
Signed-off-by: Luca Czesla <luca.czesla@mail.schwarz>
Co-developed-by: Max Lamprecht <max.lamprecht@mail.schwarz>
Signed-off-by: Max Lamprecht <max.lamprecht@mail.schwarz>
Signed-off-by: Felix Huettner <felix.huettner@mail.schwarz>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: add missing module descriptions

W=1 builds warn on missing MODULE_DESCRIPTION, add them.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: validate cta_ip via parsing

In current ctnetlink_parse_tuple_ip() function, nested parsing and
validation is splitting as two parts, which could be cleanup to a
simplified form. As the nla_parse_nested_deprecated function
supports validation in the fly. These two finially reach same place
__nla_validate_parse with same validate flag.

nla_parse_nested_deprecated
__nla_parse(.., NL_VALIDATE_LIBERAL, ..)
__nla_validate_parse

nla_validate_nested_deprecated
__nla_validate_nested(.., NL_VALIDATE_LIBERAL, ..)
__nla_validate
__nla_validate_parse

This commit removes the call to nla_validate_nested_deprecated and pass
cta_ip_nla_policy when do parsing.

Signed-off-by: Lin Ma <linma@zju.edu.cn>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: conntrack: define variables exp_nat_nla_policy and any_addr with CONFIG_NF_NAT

gcc with W=1 and ! CONFIG_NF_NAT
net/netfilter/nf_conntrack_netlink.c:3463:32: error:
‘exp_nat_nla_policy’ defined but not used [-Werror=unused-const-variable=]
3463 | static const struct nla_policy exp_nat_nla_policy[CTA_EXPECT_NAT_MAX+1] = {
| ^~~~~~~~~~~~~~~~~~
net/netfilter/nf_conntrack_netlink.c:2979:33: error:
‘any_addr’ defined but not used [-Werror=unused-const-variable=]
2979 | static const union nf_inet_addr any_addr;
| ^~~~~~~~

These variables use is controlled by CONFIG_NF_NAT, so should their definitions.

Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: conntrack: fix wrong ct->timeout value

(struct nf_conn)->timeout is an interval before the conntrack
confirmed. After confirmed, it becomes a timestamp.

It is observed that timeout of an unconfirmed conntrack:
- Set by calling ctnetlink_change_timeout(). As a result,
`nfct_time_stamp` was wrongly added to `ct->timeout` twice.
- Get by calling ctnetlink_dump_timeout(). As a result,
`nfct_time_stamp` was wrongly subtracted.

Call Trace:
<TASK>
dump_stack_lvl
ctnetlink_dump_timeout
__ctnetlink_glue_build
ctnetlink_glue_build
__nfqnl_enqueue_packet
nf_queue
nf_hook_slow
ip_mc_output
? __pfx_ip_finish_output
ip_send_skb
? __pfx_dst_output
udp_send_skb
udp_sendmsg
? __pfx_ip_generic_getfrag
sock_sendmsg

Separate the 2 cases in:
- Setting `ct->timeout` in __nf_ct_set_timeout().
- Getting `ct->timeout` in ctnetlink_dump_timeout().

Pablo appends:

Update ctnetlink to set up the timeout _after_ the IPS_CONFIRMED flag is
set on, otherwise conntrack creation via ctnetlink breaks.

Note that the problem described in this patch occurs since the
introduction of the nfnetlink_queue conntrack support, select a
sufficiently old Fixes: tag for -stable kernel to pick up this fix.

Fixes: a4b4766c3ceb ("netfilter: nfnetlink_queue: rename related to nfqueue attaching conntrack info")
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: restore IPS_CONFIRMED out of nf_conntrack_hash_check_insert()

e6d57e9ff0ae ("netfilter: conntrack: fix rmmod double-free race")
consolidates IPS_CONFIRMED bit set in nf_conntrack_hash_check_insert().
However, this breaks ctnetlink:

# conntrack -I -p tcp --timeout 123 --src 1.2.3.4 --dst 5.6.7.8 --state ESTABLISHED --sport 1 --dport 4 -u SEEN_REPLY
conntrack v1.4.6 (conntrack-tools): Operation failed: Device or resource busy

This is a partial revert of the aforementioned commit to restore
IPS_CONFIRMED.

Fixes: e6d57e9ff0ae ("netfilter: conntrack: fix rmmod double-free race")
Reported-by: Stéphane Graber <stgraber@stgraber.org>
Tested-by: Stéphane Graber <stgraber@stgraber.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: Support offloaded conntrack entry deletion

Currently, offloaded conntrack entries (flows) can only be deleted
after they are removed from offload, which is either by timeout,
tcp state change or tc ct rule deletion. This can cause issues for
users wishing to manually delete or flush existing entries.

Support deletion of offloaded conntrack entries.

Example usage:
# Delete all offloaded (and non offloaded) conntrack entries
# whose source address is 1.2.3.4
$ conntrack -D -s 1.2.3.4
# Delete all entries
$ conntrack -F

Signed-off-by: Paul Blakey <paulb@nvidia.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: ctnetlink: revert to dumping mark regardless of event type

It seems that change was unintentional, we have userspace code that
needs the mark while listening for events like REPLY, DESTROY, etc.
Also include 0-marks in requested dumps, as they were before that fix.

Fixes: 1feeae071507 ("netfilter: ctnetlink: fix compilation warning after data race fixes in ct mark")
Signed-off-by: Ivan Delalande <colona@arista.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: fix rmmod double-free race

nf_conntrack_hash_check_insert() callers free the ct entry directly, via
nf_conntrack_free.

This isn't safe anymore because
nf_conntrack_hash_check_insert() might place the entry into the conntrack
table and then delteted the entry again because it found that a conntrack
extension has been removed at the same time.

In this case, the just-added entry is removed again and an error is
returned to the caller.

Problem is that another cpu might have picked up this entry and
incremented its reference count.

This results in a use-after-free/double-free, once by the other cpu and
once by the caller of nf_conntrack_hash_check_insert().

Fix this by making nf_conntrack_hash_check_insert() not fail anymore
after the insertion, just like before the 'Fixes' commit.

This is safe because a racing nf_ct_iterate() has to wait for us
to release the conntrack hash spinlocks.

While at it, make the function return -EAGAIN in the rmmod (genid
changed) case, this makes nfnetlink replay the command (suggested
by Pablo Neira).

Fixes: c56716c69ce1 ("netfilter: extensions: introduce extension genid count")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: fix possible refcount leak in ctnetlink_create_conntrack()

nf_ct_put() needs to be called to put the refcount got by
nf_conntrack_find_get() to avoid refcount leak when
nf_conntrack_hash_check_insert() fails.

Fixes: 7d367e06688d ("netfilter: ctnetlink: fix soft lockup when netlink adds new entries (v2)")
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netlink: fix spelling mistake in dump size assert

Commit 2c7bc10d0f7b ("netlink: add macro for checking dump ctx size")
misspelled the name of the assert as asset, missing an R.

Reported-by: Ido Schimmel <idosch@idosch.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/20230123222224.732338-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

netlink: add macro for checking dump ctx size

We encourage casting struct netlink_callback::ctx to a local
struct (in a comment above the field). Provide a convenience
macro for checking if the local struct fits into the ctx.

Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

netfilter: ctnetlink: fix compilation warning after data race fixes in ct mark

All warnings (new ones prefixed by >>):

net/netfilter/nf_conntrack_netlink.c: In function '__ctnetlink_glue_build':
>> net/netfilter/nf_conntrack_netlink.c:2674:13: warning: unused variable 'mark' [-Wunused-variable]
2674 | u32 mark;
| ^~~~

Fixes: 52d1aa8b8249 ("netfilter: conntrack: Fix data-races around ct mark")
Reported-by: kernel test robot <lkp@intel.com>
Tested-by: Ivan Babrou <ivan@ivan.computer>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: Fix data-races around ct mark

nf_conn:mark can be read from and written to in parallel. Use
READ_ONCE()/WRITE_ONCE() for reads and writes to prevent unwanted
compiler optimizations.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: remove nf_conntrack_helper sysctl and modparam toggles

__nf_ct_try_assign_helper() remains in place but it now requires a
template to configure the helper.

A toggle to disable automatic helper assignment was added by:

a9006892643a ("netfilter: nf_ct_helper: allow to disable automatic helper assignment")

in 2012 to address the issues described in "Secure use of iptables and
connection tracking helpers". Automatic conntrack helper assignment was
disabled by:

3bb398d925ec ("netfilter: nf_ct_helper: disable automatic helper assignment")

back in 2016.

This patch removes the sysctl and modparam toggles, users now have to
rely on explicit conntrack helper configuration via ruleset.

Update tools/testing/selftests/netfilter/nft_conntrack_helper.sh to
check that auto-assignment does not happen anymore.

Acked-by: Aaron Conole <aconole@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net: netfilter: Add kfuncs to set and change CT status

Introduce bpf_ct_set_status and bpf_ct_change_status kfunc helpers in
order to set nf_conn field of allocated entry or update nf_conn status
field of existing inserted entry. Use nf_ct_change_status_common to
share the permitted status field changes between netlink and BPF side
by refactoring ctnetlink_change_status.

It is required to introduce two kfuncs taking nf_conn___init and nf_conn
instead of sharing one because KF_TRUSTED_ARGS flag causes strict type
checking. This would disallow passing nf_conn___init to kfunc taking
nf_conn, and vice versa. We cannot remove the KF_TRUSTED_ARGS flag as we
only want to accept refcounted pointers and not e.g. ct->master.

Hence, bpf_ct_set_* kfuncs are meant to be used on allocated CT, and
bpf_ct_change_* kfuncs are meant to be used on inserted or looked up
CT entry.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Co-developed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220721134245.2450-10-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

net: netfilter: Add kfuncs to set and change CT timeout

Introduce bpf_ct_set_timeout and bpf_ct_change_timeout kfunc helpers in
order to change nf_conn timeout. This is same as ctnetlink_change_timeout,
hence code is shared between both by extracting it out to
__nf_ct_change_timeout. It is also updated to return an error when it
sees IPS_FIXED_TIMEOUT_BIT bit in ct->status, as that check was missing.

It is required to introduce two kfuncs taking nf_conn___init and nf_conn
instead of sharing one because KF_TRUSTED_ARGS flag causes strict type
checking. This would disallow passing nf_conn___init to kfunc taking
nf_conn, and vice versa. We cannot remove the KF_TRUSTED_ARGS flag as we
only want to accept refcounted pointers and not e.g. ct->master.

Apart from this, bpf_ct_set_timeout is only called for newly allocated
CT so it doesn't need to inspect the status field just yet. Sharing the
helpers even if it was possible would make timeout setting helper
sensitive to order of setting status and timeout after allocation.

Hence, bpf_ct_set_* kfuncs are meant to be used on allocated CT, and
bpf_ct_change_* kfuncs are meant to be used on inserted or looked up
CT entry.

Co-developed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220721134245.2450-9-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

net: netfilter: Add kfuncs to allocate and insert CT

Introduce bpf_xdp_ct_alloc, bpf_skb_ct_alloc and bpf_ct_insert_entry
kfuncs in order to insert a new entry from XDP and TC programs.
Introduce bpf_nf_ct_tuple_parse utility routine to consolidate common
code.

We extract out a helper __nf_ct_set_timeout, used by the ctnetlink and
nf_conntrack_bpf code, extract it out to nf_conntrack_core, so that
nf_conntrack_bpf doesn't need a dependency on CONFIG_NF_CT_NETLINK.
Later this helper will be reused as a helper to set timeout of allocated
but not yet inserted CT entry.

The allocation functions return struct nf_conn___init instead of
nf_conn, to distinguish allocated CT from an already inserted or looked
up CT. This is later used to enforce restrictions on what kfuncs
allocated CT can be used with.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Co-developed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220721134245.2450-8-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

netfilter: nf_conntrack: use rcu accessors where needed

Sparse complains about direct access to the 'helper' and timeout members.
Both have __rcu annotation, so use the accessors.

xt_CT is fine, accesses occur before the structure is visible to other
cpus. Switch to rcu accessors there as well to reduce noise.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: fix crash due to confirmed bit load reordering

Kajetan Puchalski reports crash on ARM, with backtrace of:

__nf_ct_delete_from_lists
nf_ct_delete
early_drop
__nf_conntrack_alloc

Unlike atomic_inc_not_zero, refcount_inc_not_zero is not a full barrier.
conntrack uses SLAB_TYPESAFE_BY_RCU, i.e. it is possible that a 'newly'
allocated object is still in use on another CPU:

CPU1 CPU2
encounter 'ct' during hlist walk
delete_from_lists
refcount drops to 0
kmem_cache_free(ct);
__nf_conntrack_alloc() // returns same object
refcount_inc_not_zero(ct); /* might fail */

/* If set, ct is public/in the hash table */
test_bit(IPS_CONFIRMED_BIT, &ct->status);

In case CPU1 already set refcount back to 1, refcount_inc_not_zero()
will succeed.

The expected possibilities for a CPU that obtained the object 'ct'
(but no reference so far) are:

1. refcount_inc_not_zero() fails. CPU2 ignores the object and moves to
the next entry in the list. This happens for objects that are about
to be free'd, that have been free'd, or that have been reallocated
by __nf_conntrack_alloc(), but where the refcount has not been
increased back to 1 yet.

2. refcount_inc_not_zero() succeeds. CPU2 checks the CONFIRMED bit
in ct->status. If set, the object is public/in the table.

If not, the object must be skipped; CPU2 calls nf_ct_put() to
un-do the refcount increment and moves to the next object.

Parallel deletion from the hlists is prevented by a
'test_and_set_bit(IPS_DYING_BIT, &ct->status);' check, i.e. only one
cpu will do the unlink, the other one will only drop its reference count.

Because refcount_inc_not_zero is not a full barrier, CPU2 may try to
delete an object that is not on any list:

1. refcount_inc_not_zero() successful (refcount inited to 1 on other CPU)
2. CONFIRMED test also successful (load was reordered or zeroing
of ct->status not yet visible)
3. delete_from_lists unlinks entry not on the hlist, because
IPS_DYING_BIT is 0 (already cleared).

2) is already wrong: CPU2 will handle a partially initited object
that is supposed to be private to CPU1.

Add needed barriers when refcount_inc_not_zero() is successful.

It also inserts a smp_wmb() before the refcount is set to 1 during
allocation.

Because other CPU might still see the object, refcount_set(1)
"resurrects" it, so we need to make sure that other CPUs will also observe
the right content. In particular, the CONFIRMED bit test must only pass
once the object is fully initialised and either in the hash or about to be
inserted (with locks held to delay possible unlink from early_drop or
gc worker).

I did not change flow_offload_alloc(), as far as I can see it should call
refcount_inc(), not refcount_inc_not_zero(): the ct object is attached to
the skb so its refcount should be >= 1 in all cases.

v2: prefer smp_acquire__after_ctrl_dep to smp_rmb (Will Deacon).
v3: keep smp_acquire__after_ctrl_dep close to refcount_inc_not_zero call
add comment in nf_conntrack_netlink, no control dependency there
due to locks.

Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/all/Yr7WTfd6AVTQkLjI@e126311.manchester.arm.com/
Reported-by: Kajetan Puchalski <kajetan.puchalski@arm.com>
Diagnosed-by: Will Deacon <will@kernel.org>
Fixes: 719774377622 ("netfilter: conntrack: convert to refcount_t api")
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Will Deacon <will@kernel.org>

netfilter: ctnetlink: fix up for "netfilter: conntrack: remove unconfirmed list"

After merging the net-next tree, today's linux-next build (powerpc
ppc64_defconfig) produced this warning:

nf_conntrack_netlink.c:1717 warning: 'ctnetlink_dump_one_entry' defined but not used

Fixes: 8a75a2c17410 ("netfilter: conntrack: remove unconfirmed list")
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: conntrack: add nf_ct_iter_data object for nf_ct_iterate_cleanup*()

This patch adds a structure to collect all the context data that is
passed to the cleanup iterator.

struct nf_ct_iter_data {
struct net *net;
void *data;
u32 portid;
int report;
};

There is a netns field that allows to clean up conntrack entries
specifically owned by the specified netns.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: remove unconfirmed list

It has no function anymore and can be removed.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: remove the percpu dying list

Its no longer needed. Entries that need event redelivery are placed
on the new pernet dying list.

The advantage is that there is no need to take additional spinlock on
conntrack removal unless event redelivery failed or the conntrack entry
was never added to the table in the first place (confirmed bit not set).

The IPS_CONFIRMED bit now needs to be set as soon as the entry has been
unlinked from the unconfirmed list, else the destroy function may
attempt to unlink it a second time.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: include ecache dying list in dumps

The new pernet dying list includes conntrack entries that await
delivery of the 'destroy' event via ctnetlink.

The old percpu dying list will be removed soon.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: split inner loop of list dumping to own function

This allows code re-use in the followup patch.
No functional changes intended.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: use dump structure instead of raw args

netlink_dump structure has a union of 'long args[6]' and a context
buffer as scratch space.

Convert ctnetlink to use a structure, its easier to read than the
raw 'args' usage which comes with no type checks and no readable names.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: disable helper autoassign

When userspace, e.g. conntrackd, inserts an entry with a specified helper,
its possible that the helper is lost immediately after its added:

ctnetlink_create_conntrack
-> nf_ct_helper_ext_add + assign helper
-> ctnetlink_setup_nat
-> ctnetlink_parse_nat_setup
-> parse_nat_setup -> nfnetlink_parse_nat_setup
-> nf_nat_setup_info
-> nf_conntrack_alter_reply
-> __nf_ct_try_assign_helper

... and __nf_ct_try_assign_helper will zero the helper again.

Set IPS_HELPER bit to bypass auto-assign logic, its unwanted, just like
when helper is assigned via ruleset.

Dropped old 'not strictly necessary' comment, it referred to use of
rcu_assign_pointer() before it got replaced by RCU_INIT_POINTER().

NB: Fixes tag intentionally incorrect, this extends the referenced commit,
but this change won't build without IPS_HELPER introduced there.

Fixes: 6714cf5465d280 ("netfilter: nf_conntrack: fix explicit helper attachment and NAT")
Reported-by: Pham Thanh Tuyen <phamtyn@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: make function op structures const

No functional changes, these structures should be const.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: convert to refcount_t api

Convert nf_conn reference counting from atomic_t to refcount_t based api.
refcount_t api provides more runtime sanity checks and will warn on
certain constructs, e.g. refcount_inc() on a zero reference count, which
usually indicates use-after-free.

For this reason template allocation is changed to init the refcount to
1, the subsequenct add operations are removed.

Likewise, init_conntrack() is changed to set the initial refcount to 1
instead refcount_inc().

This is safe because the new entry is not (yet) visible to other cpus.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: remove useless type conversion to bool

dying is bool, the type conversion to true/false value is not
needed.

Signed-off-by: Bernard Zhao <bernard@vivo.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net: align static siphash keys

siphash keys use 16 bytes.

Define siphash_aligned_key_t macro so that we can make sure they
are not crossing a cache line boundary.

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

netfilter: ctnetlink: remove expired entries first

When dumping conntrack table to userspace via ctnetlink, check if the ct has
already expired before doing any of the 'skip' checks.

This expires dead entries faster.
/proc handler also removes outdated entries first.

Reported-by: Vitaly Zuevsky <vzuevsky@ns1.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: annotate data-races around ct->timeout

(struct nf_conn)->timeout can be read/written locklessly,
add READ_ONCE()/WRITE_ONCE() to prevent load/store tearing.

BUG: KCSAN: data-race in __nf_conntrack_alloc / __nf_conntrack_find_get

write to 0xffff888132e78c08 of 4 bytes by task 6029 on cpu 0:
__nf_conntrack_alloc+0x158/0x280 net/netfilter/nf_conntrack_core.c:1563
init_conntrack+0x1da/0xb30 net/netfilter/nf_conntrack_core.c:1635
resolve_normal_ct+0x502/0x610 net/netfilter/nf_conntrack_core.c:1746
nf_conntrack_in+0x1c5/0x88f net/netfilter/nf_conntrack_core.c:1901
ipv6_conntrack_local+0x19/0x20 net/netfilter/nf_conntrack_proto.c:414
nf_hook_entry_hookfn include/linux/netfilter.h:142 [inline]
nf_hook_slow+0x72/0x170 net/netfilter/core.c:619
nf_hook include/linux/netfilter.h:262 [inline]
NF_HOOK include/linux/netfilter.h:305 [inline]
ip6_xmit+0xa3a/0xa60 net/ipv6/ip6_output.c:324
inet6_csk_xmit+0x1a2/0x1e0 net/ipv6/inet6_connection_sock.c:135
__tcp_transmit_skb+0x132a/0x1840 net/ipv4/tcp_output.c:1402
tcp_transmit_skb net/ipv4/tcp_output.c:1420 [inline]
tcp_write_xmit+0x1450/0x4460 net/ipv4/tcp_output.c:2680
__tcp_push_pending_frames+0x68/0x1c0 net/ipv4/tcp_output.c:2864
tcp_push_pending_frames include/net/tcp.h:1897 [inline]
tcp_data_snd_check+0x62/0x2e0 net/ipv4/tcp_input.c:5452
tcp_rcv_established+0x880/0x10e0 net/ipv4/tcp_input.c:5947
tcp_v6_do_rcv+0x36e/0xa50 net/ipv6/tcp_ipv6.c:1521
sk_backlog_rcv include/net/sock.h:1030 [inline]
__release_sock+0xf2/0x270 net/core/sock.c:2768
release_sock+0x40/0x110 net/core/sock.c:3300
sk_stream_wait_memory+0x435/0x700 net/core/stream.c:145
tcp_sendmsg_locked+0xb85/0x25a0 net/ipv4/tcp.c:1402
tcp_sendmsg+0x2c/0x40 net/ipv4/tcp.c:1440
inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:644
sock_sendmsg_nosec net/socket.c:704 [inline]
sock_sendmsg net/socket.c:724 [inline]
__sys_sendto+0x21e/0x2c0 net/socket.c:2036
__do_sys_sendto net/socket.c:2048 [inline]
__se_sys_sendto net/socket.c:2044 [inline]
__x64_sys_sendto+0x74/0x90 net/socket.c:2044
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888132e78c08 of 4 bytes by task 17446 on cpu 1:
nf_ct_is_expired include/net/netfilter/nf_conntrack.h:286 [inline]
____nf_conntrack_find net/netfilter/nf_conntrack_core.c:776 [inline]
__nf_conntrack_find_get+0x1c7/0xac0 net/netfilter/nf_conntrack_core.c:807
resolve_normal_ct+0x273/0x610 net/netfilter/nf_conntrack_core.c:1734
nf_conntrack_in+0x1c5/0x88f net/netfilter/nf_conntrack_core.c:1901
ipv6_conntrack_local+0x19/0x20 net/netfilter/nf_conntrack_proto.c:414
nf_hook_entry_hookfn include/linux/netfilter.h:142 [inline]
nf_hook_slow+0x72/0x170 net/netfilter/core.c:619
nf_hook include/linux/netfilter.h:262 [inline]
NF_HOOK include/linux/netfilter.h:305 [inline]
ip6_xmit+0xa3a/0xa60 net/ipv6/ip6_output.c:324
inet6_csk_xmit+0x1a2/0x1e0 net/ipv6/inet6_connection_sock.c:135
__tcp_transmit_skb+0x132a/0x1840 net/ipv4/tcp_output.c:1402
__tcp_send_ack+0x1fd/0x300 net/ipv4/tcp_output.c:3956
tcp_send_ack+0x23/0x30 net/ipv4/tcp_output.c:3962
__tcp_ack_snd_check+0x2d8/0x510 net/ipv4/tcp_input.c:5478
tcp_ack_snd_check net/ipv4/tcp_input.c:5523 [inline]
tcp_rcv_established+0x8c2/0x10e0 net/ipv4/tcp_input.c:5948
tcp_v6_do_rcv+0x36e/0xa50 net/ipv6/tcp_ipv6.c:1521
sk_backlog_rcv include/net/sock.h:1030 [inline]
__release_sock+0xf2/0x270 net/core/sock.c:2768
release_sock+0x40/0x110 net/core/sock.c:3300
tcp_sendpage+0x94/0xb0 net/ipv4/tcp.c:1114
inet_sendpage+0x7f/0xc0 net/ipv4/af_inet.c:833
rds_tcp_xmit+0x376/0x5f0 net/rds/tcp_send.c:118
rds_send_xmit+0xbed/0x1500 net/rds/send.c:367
rds_send_worker+0x43/0x200 net/rds/threads.c:200
process_one_work+0x3fc/0x980 kernel/workqueue.c:2298
worker_thread+0x616/0xa70 kernel/workqueue.c:2445
kthread+0x2c7/0x2e0 kernel/kthread.c:327
ret_from_fork+0x1f/0x30

value changed: 0x00027cc2 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 17446 Comm: kworker/u4:5 Tainted: G W 5.16.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: krdsd rds_send_worker

Note: I chose an arbitrary commit for the Fixes: tag,
because I do not think we need to backport this fix to very old kernels.

Fixes: e37542ba111f ("netfilter: conntrack: avoid possible false sharing")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: do not erase error code with EINVAL

And be consistent in error management for both orig/reply filtering

Fixes: cb8aa9a3affb ("netfilter: ctnetlink: add kernel side filtering for dump")
Signed-off-by: Florent Fourcot <florent.fourcot@wifirst.fr>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: fix filtering with CTA_TUPLE_REPLY

filter->orig_flags was used for a reply context.

Fixes: cb8aa9a3affb ("netfilter: ctnetlink: add kernel side filtering for dump")
Signed-off-by: Florent Fourcot <florent.fourcot@wifirst.fr>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: refuse insertion if chain has grown too large

Also add a stat counter for this that gets exported both via old /proc
interface and ctnetlink.

Assuming the old default size of 16536 buckets and max hash occupancy of
64k, this results in 128k insertions (origin+reply), so ~8 entries per
chain on average.

The revised settings in this series will result in about two entries per
bucket on average.

This allows a hard-limit ceiling of 64.

This is not tunable at the moment, but its possible to either increase
nf_conntrack_buckets or decrease nf_conntrack_max to reduce average
lengths.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: missing counters and timestamp in nfnetlink_{log,queue}

Add counters and timestamps (if available) to the conntrack object
that is represented in nfnetlink_log and _queue messages.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ecache: remove nf_exp_event_notifier structure

Reuse the conntrack event notofier struct, this allows to remove the
extra register/unregister functions and avoids a pointer in struct net.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ecache: prepare for event notifier merge

This prepares for merge for ct and exp notifier structs.

The 'fcn' member is renamed to something unique.
Second, the register/unregister api is simplified. There is only
one implementation so there is no need to do any error checking.

Replace the EBUSY logic with WARN_ON_ONCE. This allows to remove
error unwinding.

The exp notifier register/unregister function is removed in
a followup patch.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ecache: remove one indent level

nf_conntrack_eventmask_report and nf_ct_deliver_cached_events shared
most of their code. This unifies the layout by changing

if (nf_ct_is_confirmed(ct)) {
foo
}

to
if (!nf_ct_is_confirmed(ct)))
return
foo

This removes one level of indentation.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: allow to filter dump by status bits

If CTA_STATUS is present, but CTA_STATUS_MASK is not, then the
mask is automatically set to 'status', so that kernel returns those
entries that have all of the requested bits set.

This makes more sense than using a all-one mask since we'd hardly
ever find a match.

There are no other checks for status bits, so if e.g. userspace
sets impossible combinations it will get an empty dump.

If kernel would reject unknown status bits, then a program that works on
a future kernel that has IPS_FOO bit fails on old kernels.

Same for 'impossible' combinations:

Kernel never sets ASSURED without first having set SEEN_REPLY, but its
possible that a future kernel could do so.

Therefore no sanity tests other than a 0-mask.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: add and use a helper for mark parsing

ctnetlink dumps can be filtered based on the connmark.

Prepare for status bit filtering by using a named structure and by
moving the mark parsing code to a helper.

Else ctnetlink_alloc_filter size grows a bit too big for my taste
when status handling is added.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: suspicious RCU usage in ctnetlink_dump_helpinfo

Two patches listed below removed ctnetlink_dump_helpinfo call from under
rcu_read_lock. Now its rcu_dereference generates following warning:
=============================
WARNING: suspicious RCU usage
5.13.0+ #5 Not tainted
-----------------------------
net/netfilter/nf_conntrack_netlink.c:221 suspicious rcu_dereference_check() usage!

other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
stack backtrace:
CPU: 1 PID: 2251 Comm: conntrack Not tainted 5.13.0+ #5
Call Trace:
dump_stack+0x7f/0xa1
ctnetlink_dump_helpinfo+0x134/0x150 [nf_conntrack_netlink]
ctnetlink_fill_info+0x2c2/0x390 [nf_conntrack_netlink]
ctnetlink_dump_table+0x13f/0x370 [nf_conntrack_netlink]
netlink_dump+0x10c/0x370
__netlink_dump_start+0x1a7/0x260
ctnetlink_get_conntrack+0x1e5/0x250 [nf_conntrack_netlink]
nfnetlink_rcv_msg+0x613/0x993 [nfnetlink]
netlink_rcv_skb+0x50/0x100
nfnetlink_rcv+0x55/0x120 [nfnetlink]
netlink_unicast+0x181/0x260
netlink_sendmsg+0x23f/0x460
sock_sendmsg+0x5b/0x60
__sys_sendto+0xf1/0x160
__x64_sys_sendto+0x24/0x30
do_syscall_64+0x36/0x70
entry_SYSCALL_64_after_hwframe+0x44/0xae

Fixes: 49ca022bccc5 ("netfilter: ctnetlink: don't dump ct extensions of unconfirmed conntracks")
Fixes: 0b35f6031a00 ("netfilter: Remove duplicated rcu_read_lock.")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nfnetlink: add struct nfgenmsg to struct nfnl_info and use it

Update the nfnl_info structure to add a pointer to the nfnetlink header.
This simplifies the existing codebase since this header is usually
accessed. Update existing clients to use this new field.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: use nfnetlink_unicast()

Replace netlink_unicast() calls by nfnetlink_unicast() which already
deals with translating EAGAIN to ENOBUFS as the nfnetlink core expects.

nfnetlink_unicast() calls nlmsg_unicast() which returns zero in case of
success, otherwise the netlink core function netlink_rcv_skb() turns
err > 0 into an acknowlegment.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nfnetlink: consolidate callback types

Add enum nfnl_callback_type to identify the callback type to provide one
single callback.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nfnetlink: add struct nfnl_info and pass it to callbacks

Add a new structure to reduce callback footprint and to facilite
extensions of the nfnetlink callback interface in the future.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: move ct counter to net_generic data

Its only needed from slowpath (sysctl, ctnetlink, gc worker) and
when a new conntrack object is allocated.

Furthermore, each write dirties the otherwise read-mostly pernet
data in struct net.ct, which are accessed from packet path.

Move it to the net_generic data. This makes struct netns_ct
read-mostly.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: add helper function to set up the nfnetlink header and use it

This patch adds a helper function to set up the netlink and nfnetlink headers.
Update existing codebase to use it.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: fix dump of the expect mask attribute

Before this change, the mask is never included in the netlink message, so
"conntrack -E expect" always prints 0.0.0.0.

In older kernels the l3num callback struct was passed as argument, based
on tuple->src.l3num. After the l3num indirection got removed, the call
chain is based on m.src.l3num, but this value is 0xffff.

Init l3num to the correct value.

Fixes: f957be9d349a3 ("netfilter: conntrack: remove ctnetlink callbacks from l3 protocol trackers")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: remove get_ct indirection

Use nf_ct_get() directly, its a small inline helper without dependencies.

Add CONFIG_NF_CONNTRACK guards to elide the relevant part when conntrack
isn't available at all.

v2: add ifdef guard around nf_ct_get call (kernel test robot)
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: add timeout and protoinfo to destroy events

DESTROY events do not include the remaining timeout.

Add the timeout if the entry was removed explicitly. This can happen
when a conntrack gets deleted prematurely, e.g. due to a tcp reset,
module removal, netdev notifier (nat/masquerade device went down),
ctnetlink and so on.

Add the protocol state too for the destroy message to check for abnormal
state on connection termination.

Joint work with Pablo.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: fix mark based dump filtering regression

conntrack mark based dump filtering may falsely skip entries if a mask
is given: If the mask-based check does not filter out the entry, the
else-if check is always true and compares the mark without considering
the mask. The if/else-if logic seems wrong.

Given that the mask during filter setup is implicitly set to 0xffffffff
if not specified explicitly, the mark filtering flags seem to just
complicate things. Restore the previously used approach by always
matching against a zero mask is no filter mark is given.

Fixes: cb8aa9a3affb ("netfilter: ctnetlink: add kernel side filtering for dump")
Signed-off-by: Martin Willi <martin@strongswan.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: add a range check for l3/l4 protonum

The indexes to the nf_nat_l[34]protos arrays come from userspace. So
check the tuple's family, e.g. l3num, when creating the conntrack in
order to prevent an OOB memory access during setup. Here is an example
kernel panic on 4.14.180 when userspace passes in an index greater than
NFPROTO_NUMPROTO.

Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
Modules linked in:...
Process poc (pid: 5614, stack limit = 0x00000000a3933121)
CPU: 4 PID: 5614 Comm: poc Tainted: G S W O 4.14.180-g051355490483
Hardware name: Qualcomm Technologies, Inc. SM8150 V2 PM8150 Google Inc. MSM
task: 000000002a3dfffe task.stack: 00000000a3933121
pc : __cfi_check_fail+0x1c/0x24
lr : __cfi_check_fail+0x1c/0x24
...
Call trace:
__cfi_check_fail+0x1c/0x24
name_to_dev_t+0x0/0x468
nfnetlink_parse_nat_setup+0x234/0x258
ctnetlink_parse_nat_setup+0x4c/0x228
ctnetlink_new_conntrack+0x590/0xc40
nfnetlink_rcv_msg+0x31c/0x4d4
netlink_rcv_skb+0x100/0x184
nfnetlink_rcv+0xf4/0x180
netlink_unicast+0x360/0x770
netlink_sendmsg+0x5a0/0x6a4
___sys_sendmsg+0x314/0x46c
SyS_sendmsg+0xb4/0x108
el0_svc_naked+0x34/0x38

This crash is not happening since 5.4+, however, ctnetlink still
allows for creating entries with unsupported layer 3 protocol number.

Fixes: c1d10adb4a521 ("[NETFILTER]: Add ctnetlink port for nf_conntrack")
Signed-off-by: Will McVicker <willmcvicker@google.com>
[pablo@netfilter.org: rebased original patch on top of nf.git]
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: add clash resolution stat counter

There is a misconception about what "insert_failed" means.

We increment this even when a clash got resolved, so it might not indicate
a problem.

Add a dedicated counter for clash resolution and only increment
insert_failed if a clash cannot be resolved.

For the old /proc interface, export this in place of an older stat
that got removed a while back.
For ctnetlink, export this with a new attribute.

Also correct an outdated comment that implies we add a duplicate tuple --
we only add the (unique) reply direction.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: remove ignore stats

This counter increments when nf_conntrack_in sees a packet that already
has a conntrack attached or when the packet is marked as UNTRACKED.
Neither is an error.

The former is normal for loopback traffic. The second happens for
certain ICMPv6 packets or when nftables/ip(6)tables rules are in place.

In case someone needs to count UNTRACKED packets, or packets
that are marked as untracked before conntrack_in this can be done with
both nftables and ip(6)tables rules.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: memleak in filter initialization error path

Release the filter object in case of error.

Fixes: cb8aa9a3affb ("netfilter: ctnetlink: add kernel side filtering for dump")
Reported-by: syzbot+38b8b548a851a01793c5@syzkaller.appspotmail.com
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: add kernel side filtering for dump

Conntrack dump does not support kernel side filtering (only get exists,
but it returns only one entry. And user has to give a full valid tuple)

It means that userspace has to implement filtering after receiving many
irrelevant entries, consuming resources (conntrack table is sometimes
very huge, much more than a routing table for example).

This patch adds filtering in kernel side. To achieve this goal, we:

* Add a new CTA_FILTER netlink attributes, actually a flag list to
parametize filtering
* Convert some *nlattr_to_tuple() functions, to allow a partial parsing
of CTA_TUPLE_ORIG and CTA_TUPLE_REPLY (so nf_conntrack_tuple it not
fully set)

Filtering is now possible on:
* IP SRC/DST values
* Ports for TCP and UDP flows
* IMCP(v6) codes types and IDs

Filtering is done as an "AND" operator. For example, when flags
PROTO_SRC_PORT, PROTO_NUM and IP_SRC are sets, only entries matching all
values are dumped.

Changes since v1:
Set NLM_F_DUMP_FILTERED in nlm flags if entries are filtered

Changes since v2:
Move several constants to nf_internals.h
Move a fix on netlink values check in a separate patch
Add a check on not-supported flags
Return EOPNOTSUPP if CDA_FILTER is set in ctnetlink_flush_conntrack
(not yet implemented)
Code style issues

Changes since v3:
Fix compilation warning reported by kbuild test robot

Changes since v4:
Fix a regression introduced in v3 (returned EINVAL for valid netlink
messages without CTA_MARK)

Changes since v5:
Change definition of CTA_FILTER_F_ALL
Fix a regression when CTA_TUPLE_ZONE is not set

Signed-off-by: Romain Bellan <romain.bellan@wifirst.fr>
Signed-off-by: Florent Fourcot <florent.fourcot@wifirst.fr>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: be more strict when NF_CONNTRACK_MARK is not set

When CONFIG_NF_CONNTRACK_MARK is not set, any CTA_MARK or CTA_MARK_MASK
in netlink message are not supported. We should return an error when one
of them is set, not both

Fixes: 9306425b70bf ("netfilter: ctnetlink: must check mark attributes vs NULL")
Signed-off-by: Romain Bellan <romain.bellan@wifirst.fr>
Signed-off-by: Florent Fourcot <florent.fourcot@wifirst.fr>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: Add missing annotation for ctnetlink_parse_nat_setup()

Sparse reports a warning at ctnetlink_parse_nat_setup()

warning: context imbalance in ctnetlink_parse_nat_setup()
- unexpected unlock

The root cause is the missing annotation at ctnetlink_parse_nat_setup()
Add the missing __must_hold(RCU) annotation

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: netns exit must wait for callbacks

Curtis Taylor and Jon Maxwell reported and debugged a crash on 3.10
based kernel.

Crash occurs in ctnetlink_conntrack_events because net->nfnl socket is
NULL. The nfnl socket was set to NULL by netns destruction running on
another cpu.

The exiting network namespace calls the relevant destructors in the
following order:

1. ctnetlink_net_exit_batch

This nulls out the event callback pointer in struct netns.

2. nfnetlink_net_exit_batch

This nulls net->nfnl socket and frees it.

3. nf_conntrack_cleanup_net_list

This removes all remaining conntrack entries.

This is order is correct. The only explanation for the crash so ar is:

cpu1: conntrack is dying, eviction occurs:
-> nf_ct_delete()
-> nf_conntrack_event_report \
-> nf_conntrack_eventmask_report
-> notify->fcn() (== ctnetlink_conntrack_events).

cpu1: a. fetches rcu protected pointer to obtain ctnetlink event callback.
b. gets interrupted.
cpu2: runs netns exit handlers:
a runs ctnetlink destructor, event cb pointer set to NULL.
b runs nfnetlink destructor, nfnl socket is closed and set to NULL.
cpu1: c. resumes and trips over NULL net->nfnl.

Problem appears to be that ctnetlink_net_exit_batch only prevents future
callers of nf_conntrack_eventmask_report() from obtaining the callback.
It doesn't wait of other cpus that might have already obtained the
callbacks address.

I don't see anything in upstream kernels that would prevent similar
crash: We need to wait for all cpus to have exited the event callback.

Fixes: 9592a5c01e79dbc59eb56fa ("netfilter: ctnetlink: netns support")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: don't dump ct extensions of unconfirmed conntracks

When dumping the unconfirmed lists, the cpu that is processing the ct
entry can reallocate ct->ext at any time.

Right now accessing the extensions from another CPU is ok provided
we're holding rcu read lock: extension reallocation does use rcu.

Once RCU isn't used anymore this becomes unsafe, so skip extensions for
the unconfirmed list.

Dumping the extension area for confirmed or dying conntracks is fine:
no reallocations are allowed and list iteration holds appropriate
locks that prevent ct (and this ct->ext) from getting free'd.

v2: fix compiler warnings due to misue of 'const' and missing return
statement (kbuild robot).

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: honor IPS_OFFLOAD flag

If this flag is set, timeout and state are irrelevant to userspace.

Fixes: 90964016e5d3 ("netfilter: nf_conntrack: add IPS_OFFLOAD status bit")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_conntrack_sip: fix expectation clash

When conntracks change during a dialog, SDP messages may be sent from
different conntracks to establish expects with identical tuples. In this
case expects conflict may be detected for the 2nd SDP message and end up
with a process failure.

The fixing here is to reuse an existing expect who has the same tuple for a
different conntrack if any.

Here are two scenarios for the case.

1)
SERVER CPE

| INVITE SDP |
5060 |<----------------------|5060
| 100 Trying |
5060 |---------------------->|5060
| 183 SDP |
5060 |---------------------->|5060 ===> Conntrack 1
| PRACK |
50601 |<----------------------|5060
| 200 OK (PRACK) |
50601 |---------------------->|5060
| 200 OK (INVITE) |
5060 |---------------------->|5060
| ACK |
50601 |<----------------------|5060
| |
|<--- RTP stream ------>|
| |
| INVITE SDP (t38) |
50601 |---------------------->|5060 ===> Conntrack 2

With a certain configuration in the CPE, SIP messages "183 with SDP" and
"re-INVITE with SDP t38" will go through the sip helper to create
expects for RTP and RTCP.

It is okay to create RTP and RTCP expects for "183", whose master
connection source port is 5060, and destination port is 5060.

In the "183" message, port in Contact header changes to 50601 (from the
original 5060). So the following requests e.g. PRACK and ACK are sent to
port 50601. It is a different conntrack (let call Conntrack 2) from the
original INVITE (let call Conntrack 1) due to the port difference.

In this example, after the call is established, there is RTP stream but no
RTCP stream for Conntrack 1, so the RTP expect created upon "183" is
cleared, and RTCP expect created for Conntrack 1 retains.

When "re-INVITE with SDP t38" arrives to create RTP&RTCP expects, current
ALG implementation will call nf_ct_expect_related() for RTP and RTCP. The
expects tuples are identical to those for Conntrack 1. RTP expect for
Conntrack 2 succeeds in creation as the one for Conntrack 1 has been
removed. RTCP expect for Conntrack 2 fails in creation because it has
idential tuples and 'conflict' with the one retained for Conntrack 1. And
then result in a failure in processing of the re-INVITE.

2)

SERVER A CPE

| REGISTER |
5060 |<------------------| 5060 ==> CT1
| 200 |
5060 |------------------>| 5060
| |
| INVITE SDP(1) |
5060 |<------------------| 5060
| 300(multi choice) |
5060 |------------------>| 5060 SERVER B
| ACK |
5060 |<------------------| 5060
| INVITE SDP(2) |
5060 |-------------------->| 5060 ==> CT2
| 100 |
5060 |<--------------------| 5060
| 200(contact changes)|
5060 |<--------------------| 5060
| ACK |
5060 |-------------------->| 50601 ==> CT3
| |
|<--- RTP stream ---->|
| |
| BYE |
5060 |<--------------------| 50601
| 200 |
5060 |-------------------->| 50601
| INVITE SDP(3) |
5060 |<------------------| 5060 ==> CT1

CPE sends an INVITE request(1) to Server A, and creates a RTP&RTCP expect
pair for this Conntrack 1 (CT1). Server A responds 300 to redirect to
Server B. The RTP&RTCP expect pairs created on CT1 are removed upon 300
response.

CPE sends the INVITE request(2) to Server B, and creates an expect pair
for the new conntrack (due to destination address difference), let call
CT2. Server B changes the port to 50601 in 200 OK response, and the
following requests ACK and BYE from CPE are sent to 50601. The call is
established. There is RTP stream and no RTCP stream. So RTP expect is
removed and RTCP expect for CT2 retains.

As BYE request is sent from port 50601, it is another conntrack, let call
CT3, different from CT2 due to the port difference. So the BYE request will
not remove the RTCP expect for CT2.

Then another outgoing call is made, with the same RTP port being used (not
definitely but possibly). CPE firstly sends the INVITE request(3) to Server
A, and tries to create a RTP&RTCP expect pairs for this CT1. In current ALG
implementation, the RTCP expect for CT1 fails in creation because it
'conflicts' with the residual one for CT2. As a result the INVITE request
fails to send.

Signed-off-by: xiao ruizhu <katrina.xiaorz@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: Fix regression in conntrack entry deletion

Commit f8e608982022 ("netfilter: ctnetlink: Resolve conntrack
L3-protocol flush regression") introduced a regression in which deletion
of conntrack entries would fail because the L3 protocol information
is replaced by AF_UNSPEC. As a result the search for the entry to be
deleted would turn up empty due to the tuple used to perform the search
is now different from the tuple used to initially set up the entry.

For flushing the conntrack table we do however want to keep the option
for nfgenmsg->version to have a non-zero value to allow for newer
user-space tools to request treatment under the new behavior. With that
it is possible to independently flush tables for a defined L3 protocol.
This was introduced with the enhancements in in commit 59c08c69c278
("netfilter: ctnetlink: Support L3 protocol-filter on flush").

Older user-space tools will retain the behavior of flushing all tables
regardless of defined L3 protocol.

Fixes: f8e608982022 ("netfilter: ctnetlink: Resolve conntrack L3-protocol flush regression")
Suggested-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Felix Kaechele <felix@kaechele.ca>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: Resolve conntrack L3-protocol flush regression

Commit 59c08c69c278 ("netfilter: ctnetlink: Support L3 protocol-filter
on flush") introduced a user-space regression when flushing connection
track entries. Before this commit, the nfgen_family field was not used
by the kernel and all entries were removed. Since this commit,
nfgen_family is used to filter out entries that should not be removed.
One example a broken tool is conntrack. conntrack always sets
nfgen_family to AF_INET, so after 59c08c69c278 only IPv4 entries were
removed with the -F parameter.

Pablo Neira Ayuso suggested using nfgenmsg->version to resolve the
regression, and this commit implements his suggestion. nfgenmsg->version
is so far set to zero, so it is well-suited to be used as a flag for
selecting old or new flush behavior. If version is 0, nfgen_family is
ignored and all entries are used. If user-space sets the version to one
(or any other value than 0), then the new behavior is used. As version
only can have two valid values, I chose not to add a new
NFNETLINK_VERSION-constant.

Fixes: 59c08c69c278 ("netfilter: ctnetlink: Support L3 protocol-filter on flush")
Reported-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Suggested-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Kristian Evensen <kristian.evensen@gmail.com>
Tested-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netlink: make validation more configurable for future strictness

We currently have two levels of strict validation:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

netlink: make nla_nest_start() add NLA_F_NESTED flag

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

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

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

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

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

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

netfilter: ctnetlink: don't use conntrack/expect object addresses as id

else, we leak the addresses to userspace via ctnetlink events
and dumps.

Compute an ID on demand based on the immutable parts of nf_conn struct.

Another advantage compared to using an address is that there is no
immediate re-use of the same ID in case the conntrack entry is freed and
reallocated again immediately.

Fixes: 3583240249ef ("[NETFILTER]: nf_conntrack_expect: kill unique ID")
Fixes: 7f85f914721f ("[NETFILTER]: nf_conntrack: kill unique ID")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: replace NF_NAT_NEEDED with IS_ENABLED(CONFIG_NF_NAT)

NF_NAT_NEEDED is true whenever nat support for either ipv4 or ipv6 is
enabled. Now that the af-specific nat configuration switches have been
removed, IS_ENABLED(CONFIG_NF_NAT) has the same effect.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nat: remove nf_nat_l3proto.h and nf_nat_core.h

The l3proto name is gone, its header file is the last trace.
While at it, also remove nf_nat_core.h, its very small and all users
include nf_nat.h too.

before:
text data bss dec hex filename
22948 1612 4136 28696 7018 nf_nat.ko

after removal of l3proto register/unregister functions:
text data bss dec hex filename
22196 1516 4136 27848 6cc8 nf_nat.ko

checkpatch complains about overly long lines, but line breaks
do not make things more readable and the line length gets smaller
here, not larger.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: fix indentation issue

A statement in an if block is not indented correctly. Fix this.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: remove nf_ct_l4proto_find_get

Its now same as __nf_ct_l4proto_find(), so rename that to
nf_ct_l4proto_find and use it everywhere.

It never returns NULL and doesn't need locks or reference counts.

Before this series:
302824 net/netfilter/nf_conntrack.ko
21504 net/netfilter/nf_conntrack_proto_gre.ko

text data bss dec hex filename
6281 1732 4 8017 1f51 nf_conntrack_proto_gre.ko
108356 20613 236 129205 1f8b5 nf_conntrack.ko

After:
294864 net/netfilter/nf_conntrack.ko
text data bss dec hex filename
106979 19557 240 126776 1ef38 nf_conntrack.ko

so, even with builtin gre, total size got reduced.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nat: remove nf_nat_l4proto struct

This removes the (now empty) nf_nat_l4proto struct, all its instances
and all the no longer needed runtime (un)register functionality.

nf_nat_need_gre() can be axed as well: the module that calls it (to
load the no-longer-existing nat_gre module) also calls other nat core
functions. GRE nat is now always available if kernel is built with it.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: always honor CTA_MARK_MASK

Useful to only set a particular range of the conntrack mark while
leaving existing parts of the value alone, e.g. when updating
conntrack marks via netlink from userspace.

For NFQUEUE it was already implemented in commit 534473c6080e
("netfilter: ctnetlink: honor CTA_MARK_MASK when setting ctmark").

This now adds the same functionality also for the other netlink
conntrack mark changes.

Signed-off-by: Andreas Jaggi <andreas.jaggi@waterwave.ch>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: must check mark attributes vs NULL

else we will oops (null deref) when the attributes aren't present.

Also add back the EOPNOTSUPP in case MARK filtering is requested but
kernel doesn't support it.

Fixes: 59c08c69c2788 ("netfilter: ctnetlink: Support L3 protocol-filter on flush")
Reported-by: syzbot+e45eda8eda6e93a03959@syzkaller.appspotmail.com
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: remove l3->l4 mapping information

l4 protocols are demuxed by l3num, l4num pair.

However, almost all l4 trackers are l3 agnostic.

Only exceptions are:
- gre, icmp (ipv4 only)
- icmpv6 (ipv6 only)

This commit gets rid of the l3 mapping, l4 trackers can now be looked up
by their IPPROTO_XXX value alone, which gets rid of the additional l3
indirection.

For icmp, ipcmp6 and gre, add a check on state->pf and
return -NF_ACCEPT in case we're asked to track e.g. icmpv6-in-ipv4,
this seems more fitting than using the generic tracker.

Additionally we can kill the 2nd l4proto definitions that were needed
for v4/v6 split -- they are now the same so we can use single l4proto
struct for each protocol, rather than two.

The EXPORT_SYMBOLs can be removed as all these object files are
part of nf_conntrack with no external references.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: Support L3 protocol-filter on flush

The same connection mark can be set on flows belonging to different
address families. This commit adds support for filtering on the L3
protocol when flushing connection track entries. If no protocol is
specified, then all L3 protocols match.

In order to avoid code duplication and a redundant check, the protocol
comparison in ctnetlink_dump_table() has been removed. Instead, a filter
is created if the GET-message triggering the dump contains an address
family. ctnetlink_filter_match() is then used to compare the L3
protocols.

Signed-off-by: Kristian Evensen <kristian.evensen@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: fix memory leaks on netlink_dump_start error

Shaochun Chen points out we leak dumper filter state allocations
stored in dump_control->data in case there is an error before netlink sets
cb_running (after which ->done will be called at some point).

In order to fix this, add .start functions and move allocations there.

Same pattern as used in commit 90fd131afc565159c9e0ea742f082b337e10f8c6
("netfilter: nf_tables: move dumper state allocation into ->start").

Reported-by: shaochun chen <cscnull@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: Remove useless param helper of nf_ct_helper_ext_add

The param helper of nf_ct_helper_ext_add is useless now, then remove
it now.

Signed-off-by: Gao Feng <gfree.wind@vip.163.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: remove ctnetlink callbacks from l3 protocol trackers

handle everything from ctnetlink directly.

After all these years we still only support ipv4 and ipv6, so it
seems reasonable to remove l3 protocol tracker support and instead
handle ipv4/ipv6 from a common, always builtin inet tracker.

Step 1: Get rid of all the l3proto->func() calls.

Start with ctnetlink, then move on to packet-path ones.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: avoid null pointer dereference

Dan Carpenter points out that deref occurs after NULL check, we should
re-fetch the pointer and check that instead.

Fixes: 2c205dd3981f7 ("netfilter: add struct nf_nat_hook and use it")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: add struct nf_nat_hook and use it

Move decode_session() and parse_nat_setup_hook() indirections to struct
nf_nat_hook structure.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: export nf_conntrack_max

IPCTNL_MSG_CT_GET_STATS netlink command allow to monitor current number
of conntrack entries. However, if one wants to compare it with the
maximum (and detect exhaustion), the only solution is currently to read
sysctl value.

This patch add nf_conntrack_max value in netlink message, and simplify
monitoring for application built on netlink API.

Signed-off-by: Florent Fourcot <florent.fourcot@wifirst.fr>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: Merge assignment with return

Merge assignment with return statement to directly return the value.

Signed-off-by: Arushi Singhal <arushisinghal19971997@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

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>

netfilter: ctnetlink: synproxy support

This patch exposes synproxy information per-conntrack. Moreover, send
sequence adjustment events once server sends us the SYN,ACK packet, so
we can synchronize the sequence adjustment too for packets going as
reply from the server, as part of the synproxy logic.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net: Convert ctnetlink_net_ops

These pernet_operations register and unregister
two conntrack notifiers, and they seem to be safe
to be executed in parallel.

General/not related to async pernet_operations JFI:
ctnetlink_net_exit_batch() actions are grouped in batch,
and this could look like there is synchronize_rcu()
is forgotten. But there is synchronize_rcu() on module
exit patch (in ctnetlink_exit()), so this batch may
be reworked as simple .exit method.

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

netfilter: remove messages print and boot/module load time

Several reasons for this:

* Several modules maintain internal version numbers, that they print at
boot/module load time, that are not exposed to userspace, as a
primitive mechanism to make revision number control from the earlier
days of Netfilter.

* IPset shows the protocol version at boot/module load time, instead
display this via module description, as Jozsef suggested.

* Remove copyright notice at boot/module load time in two spots, the
Netfilter codebase is a collective development effort, if we would
have to display copyrights for each contributor at boot/module load
time for each extensions we have, we would probably fill up logs with
lots of useless information - from a technical standpoint.

So let's be consistent and remove them all.

Acked-by: Florian Westphal <fw@strlen.de>
Acked-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_conntrack: add IPS_OFFLOAD status bit

This new bit tells us that the conntrack entry is owned by the flow
table offload infrastructure.

# cat /proc/net/nf_conntrack
ipv4 2 tcp 6 src=10.141.10.2 dst=147.75.205.195 sport=36392 dport=443 src=147.75.205.195 dst=192.168.2.195 sport=443 dport=36392 [OFFLOAD] mark=0 zone=0 use=2

Note the [OFFLOAD] tag in the listing.

The timer of such conntrack entries look like stopped from userspace.
In practise, to make sure the conntrack entry does not go away, the
conntrack timer is periodically set to an arbitrary large value that
gets refreshed on every iteration from the garbage collector, so it
never expires- and they display no internal state in the case of TCP
flows. This allows us to save a bitcheck from the packet path via
nf_ct_is_expired().

Conntrack entries that have been offloaded to the flow table
infrastructure cannot be deleted/flushed via ctnetlink. The flow table
infrastructure is also responsible for releasing this conntrack entry.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: remove nlattr_size pointer from l4proto trackers

similar to previous commit, but instead compute this at compile time
and turn nlattr_size into an u16.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net: remove duplicate includes

These duplicate includes have been found with scripts/checkincludes.pl but
they have been removed manually to avoid removing false positives.

Signed-off-by: Pravin Shedge <pravin.shedge4linux@gmail.com>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

netfilter: conntrack: clamp timeouts to INT_MAX

When the conntracking code multiplies a timeout by HZ, it can overflow
from positive to negative; this causes it to instantly expire. To
protect against this the multiplication is done in 64-bit so we can
prevent it from exceeding INT_MAX.

Signed-off-by: Jay Elliott <jelliott@arista.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: add ifdef around ctnetlink_proto_size

This function is no longer marked 'inline', so we now get a warning
when it is unused:

net/netfilter/nf_conntrack_netlink.c:536:15: error: 'ctnetlink_proto_size' defined but not used [-Werror=unused-function]

We could mark it inline again, mark it __maybe_unused, or add an #ifdef
around the definition. I'm picking the third approach here since that
seems to be what the rest of the file has.

Fixes: 5caaed151a68 ("netfilter: conntrack: don't cache nlattr_tuple_size result in nla_size")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

netfilter: conntrack: don't cache nlattr_tuple_size result in nla_size

We currently call ->nlattr_tuple_size() once at register time and
cache result in l4proto->nla_size.

nla_size is the only member that is written to, avoiding this would
allow to make l4proto trackers const.

We can use ->nlattr_tuple_size() at run time, and cache result in
the individual trackers instead.

This is an intermediate step, next patch removes nlattr_size()
callback and computes size at compile time, then removes nla_size.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: make protocol tracker pointers const

Doesn't change generated code, but will make it easier to eventually
make the actual trackers themselvers const.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: compute l3proto nla size at compile time

avoids a pointer and allows struct to be const later on.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: constify nf_conntrack_l3/4proto parameters

When a nf_conntrack_l3/4proto parameter is not on the left hand side
of an assignment, its address is not taken, and it is not passed to a
function that may modify its fields, then it can be declared as const.

This change is useful from a documentation point of view, and can
possibly facilitate making some nf_conntrack_l3/4proto structures const
subsequently.

Done with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: expect: add and use nf_ct_expect_iterate helpers

We have several spots that open-code a expect walk, add a helper
that is similar to nf_ct_iterate_destroy/nf_ct_iterate_cleanup.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: Remove duplicated rcu_read_lock.

This patch removes duplicate rcu_read_lock().

1. IPVS part:

According to Julian Anastasov's mention, contexts of ipvs are described
at: http://marc.info/?l=netfilter-devel&m=149562884514072&w=2, in summary:

- packet RX/TX: does not need locks because packets come from hooks.
- sync msg RX: backup server uses RCU locks while registering new
connections.
- ip_vs_ctl.c: configuration get/set, RCU locks needed.
- xt_ipvs.c: It is a netfilter match, running from hook context.

As result, rcu_read_lock and rcu_read_unlock can be removed from:

- ip_vs_core.c: all
- ip_vs_ctl.c:
- only from ip_vs_has_real_service
- ip_vs_ftp.c: all
- ip_vs_proto_sctp.c: all
- ip_vs_proto_tcp.c: all
- ip_vs_proto_udp.c: all
- ip_vs_xmit.c: all (contains only packet processing)

2. Netfilter part:

There are three types of functions that are guaranteed the rcu_read_lock().
First, as result, functions are only called by nf_hook():

- nf_conntrack_broadcast_help(), pptp_expectfn(), set_expected_rtp_rtcp().
- tcpmss_reverse_mtu(), tproxy_laddr4(), tproxy_laddr6().
- match_lookup_rt6(), check_hlist(), hashlimit_mt_common().
- xt_osf_match_packet().

Second, functions that caller already held the rcu_read_lock().
- destroy_conntrack(), ctnetlink_conntrack_event().
- ctnl_timeout_find_get(), nfqnl_nf_hook_drop().

Third, functions that are mixed with type1 and type2.

These functions are called by nf_hook() also these are called by
ordinary functions that already held the rcu_read_lock():

- __ctnetlink_glue_build(), ctnetlink_expect_event().
- ctnetlink_proto_size().

Applied files are below:

- nf_conntrack_broadcast.c, nf_conntrack_core.c, nf_conntrack_netlink.c.
- nf_conntrack_pptp.c, nf_conntrack_sip.c, nfnetlink_cttimeout.c.
- nfnetlink_queue.c, xt_TCPMSS.c, xt_TPROXY.c, xt_addrtype.c.
- xt_connlimit.c, xt_hashlimit.c, xt_osf.c

Detailed calltrace can be found at:
http://marc.info/?l=netfilter-devel&m=149667610710350&w=2

Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nfnetlink: extended ACK reporting

Pass down struct netlink_ext_ack as parameter to all of our nfnetlink
subsystem callbacks, so we can work on follow up patches to provide
finer grain error reporting using the new infrastructure that
2d4bc93368f5 ("netlink: extended ACK reporting") provides.

No functional change, just pass down this new object to callbacks.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: rename nf_ct_iterate_cleanup

There are several places where we needlesly call nf_ct_iterate_cleanup,
we should instead iterate the full table at module unload time.

This is a leftover from back when the conntrack table got duplicated
per net namespace.

So rename nf_ct_iterate_cleanup to nf_ct_iterate_cleanup_net.
A later patch will then add a non-net variant.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: delete extra spaces

This patch cleans up extra spaces.

Signed-off-by: linzhang <xiaolou4617@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: fix incorrect nf_ct_put during hash resize

If nf_conntrack_htable_size was adjusted by the user during the ct
dump operation, we may invoke nf_ct_put twice for the same ct, i.e.
the "last" ct. This will cause the ct will be freed but still linked
in hash buckets.

It's very easy to reproduce the problem by the following commands:
# while : ; do
echo $RANDOM > /proc/sys/net/netfilter/nf_conntrack_buckets
done
# while : ; do
conntrack -L
done
# iperf -s 127.0.0.1 &
# iperf -c 127.0.0.1 -P 60 -t 36000

After a while, the system will hang like this:
NMI watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [bash:20184]
NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [iperf:20382]
...

So at last if we find cb->args[1] is equal to "last", this means hash
resize happened, then we can set cb->args[1] to 0 to fix the above
issue.

Fixes: d205dc40798d ("[NETFILTER]: ctnetlink: fix deadlock in table dumping")
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: synproxy: fix conntrackd interaction

This patch fixes the creation of connection tracking entry from
netlink when synproxy is used. It was missing the addition of
the synproxy extension.

This was causing kernel crashes when a conntrack entry created by
conntrackd was used after the switch of traffic from active node
to the passive node.

Signed-off-by: Eric Leblond <eric@regit.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: Make some parameters integer to avoid enum mismatch

Not all parameters passed to ctnetlink_parse_tuple() and
ctnetlink_exp_dump_tuple() match the enum type in the signatures of these
functions. Since this is intended change the argument type of to be an
unsigned integer value.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: acquire ct->lock before operating nf_ct_seqadj

We should acquire the ct->lock before accessing or modifying the
nf_ct_seqadj, as another CPU may modify the nf_ct_seqadj at the same
time during its packet proccessing.

Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: make it safer when updating ct->status

After converting to use rcu for conntrack hash, one CPU may update
the ct->status via ctnetlink, while another CPU may process the
packets and update the ct->status.

So the non-atomic operation "ct->status |= status;" via ctnetlink
becomes unsafe, and this may clear the IPS_DYING_BIT bit set by
another CPU unexpectedly. For example:
CPU0 CPU1
ctnetlink_change_status __nf_conntrack_find_get
old = ct->status nf_ct_gc_expired
- nf_ct_kill
- test_and_set_bit(IPS_DYING_BIT
new = old | status; -
ct->status = new; <-- oops, _DYING_ is cleared!

Now using a series of atomic bit operation to solve the above issue.

Also note, user shouldn't set IPS_TEMPLATE, IPS_SEQ_ADJUST directly,
so make these two bits be unchangable too.

If we set the IPS_TEMPLATE_BIT, ct will be freed by nf_ct_tmpl_free,
but actually it is alloced by nf_conntrack_alloc.
If we set the IPS_SEQ_ADJUST_BIT, this may cause the NULL pointer
deference, as the nfct_seqadj(ct) maybe NULL.

Last, add some comments to describe the logic change due to the
commit a963d710f367 ("netfilter: ctnetlink: Fix regression in CTA_STATUS
processing"), which makes me feel a little confusing.

Fixes: 76507f69c44e ("[NETFILTER]: nf_conntrack: use RCU for conntrack hash")
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: fix deadlock due to acquire _expect_lock twice

Currently, ctnetlink_change_conntrack is always protected by _expect_lock,
but this will cause a deadlock when deleting the helper from a conntrack,
as the _expect_lock will be acquired again by nf_ct_remove_expectations:

CPU0
----
lock(nf_conntrack_expect_lock);
lock(nf_conntrack_expect_lock);

*** DEADLOCK ***
May be due to missing lock nesting notation

2 locks held by lt-conntrack_gr/12853:
#0: (&table[i].mutex){+.+.+.}, at: [<ffffffffa05e2009>]
nfnetlink_rcv_msg+0x399/0x6a9 [nfnetlink]
#1: (nf_conntrack_expect_lock){+.....}, at: [<ffffffffa05f2c1f>]
ctnetlink_new_conntrack+0x17f/0x408 [nf_conntrack_netlink]

Call Trace:
dump_stack+0x85/0xc2
__lock_acquire+0x1608/0x1680
? ctnetlink_parse_tuple_proto+0x10f/0x1c0 [nf_conntrack_netlink]
lock_acquire+0x100/0x1f0
? nf_ct_remove_expectations+0x32/0x90 [nf_conntrack]
_raw_spin_lock_bh+0x3f/0x50
? nf_ct_remove_expectations+0x32/0x90 [nf_conntrack]
nf_ct_remove_expectations+0x32/0x90 [nf_conntrack]
ctnetlink_change_helper+0xc6/0x190 [nf_conntrack_netlink]
ctnetlink_new_conntrack+0x1b2/0x408 [nf_conntrack_netlink]
nfnetlink_rcv_msg+0x60a/0x6a9 [nfnetlink]
? nfnetlink_rcv_msg+0x1b9/0x6a9 [nfnetlink]
? nfnetlink_bind+0x1a0/0x1a0 [nfnetlink]
netlink_rcv_skb+0xa4/0xc0
nfnetlink_rcv+0x87/0x770 [nfnetlink]

Since the operations are unrelated to nf_ct_expect, so we can drop the
_expect_lock. Also note, after removing the _expect_lock protection,
another CPU may invoke nf_conntrack_helper_unregister, so we should
use rcu_read_lock to protect __nf_conntrack_helper_find invoked by
ctnetlink_change_helper.

Fixes: ca7433df3a67 ("netfilter: conntrack: seperate expect locking from nf_conntrack_lock")
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: drop the incorrect cthelper module request

First, when creating a new ct, we will invoke request_module to try to
load the related inkernel cthelper. So there's no need to call the
request_module again when updating the ct helpinfo.

Second, ctnetlink_change_helper may be called with rcu_read_lock held,
i.e. rcu_read_lock -> nfqnl_recv_verdict -> nfqnl_ct_parse ->
ctnetlink_glue_parse -> ctnetlink_glue_parse_ct ->
ctnetlink_change_helper. But the request_module invocation may sleep,
so we can't call it with the rcu_read_lock held.

Remove it now.

Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: remove nf_ct_is_untracked

This function is now obsolete and always returns false.
This change has no effect on generated code.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netlink: pass extended ACK struct to parsing functions

Pass the new extended ACK reporting struct to all of the generic
netlink parsing functions. For now, pass NULL in almost all callers
(except for some in the core.)

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

netfilter: nf_ct_expect: use proper RCU list traversal/update APIs

We should use proper RCU list APIs to manipulate help->expectations,
as we can dump the conntrack's expectations via nfnetlink, i.e. in
ctnetlink_exp_ct_dump_table(), where only rcu_read_lock is acquired.

So for list traversal, use hlist_for_each_entry_rcu; for list add/del,
use hlist_add_head_rcu and hlist_del_rcu.

Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: skip dumping expect when nfct_help(ct) is NULL

For IPCTNL_MSG_EXP_GET, if the CTA_EXPECT_MASTER attr is specified, then
the NLM_F_DUMP request will dump the expectations related to this
connection tracking.

But we forget to check whether the conntrack has nf_conn_help or not,
so if nfct_help(ct) is NULL, oops will happen:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
IP: ctnetlink_exp_ct_dump_table+0xf9/0x1e0 [nf_conntrack_netlink]
Call Trace:
? ctnetlink_exp_ct_dump_table+0x75/0x1e0 [nf_conntrack_netlink]
netlink_dump+0x124/0x2a0
__netlink_dump_start+0x161/0x190
ctnetlink_dump_exp_ct+0x16c/0x1bc [nf_conntrack_netlink]
? ctnetlink_exp_fill_info.constprop.33+0xf0/0xf0 [nf_conntrack_netlink]
? ctnetlink_glue_seqadj+0x20/0x20 [nf_conntrack_netlink]
ctnetlink_get_expect+0x32e/0x370 [nf_conntrack_netlink]
? debug_lockdep_rcu_enabled+0x1d/0x20
nfnetlink_rcv_msg+0x60a/0x6a9 [nfnetlink]
? nfnetlink_rcv_msg+0x1b9/0x6a9 [nfnetlink]
[...]

Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: make it safer when checking the ct helper name

One CPU is doing ctnetlink_change_helper(), while another CPU is doing
unhelp() at the same time. So even if help->helper is not NULL at first,
the later statement strcmp(help->helper->name, ...) may still access
the NULL pointer.

So we must use rcu_read_lock and rcu_dereference to avoid such _bad_
thing happen.

Fixes: f95d7a46bc57 ("netfilter: ctnetlink: Fix regression in CTA_HELP processing")
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: helper: Add the rcu lock when call __nf_conntrack_helper_find

When invoke __nf_conntrack_helper_find, it needs the rcu lock to
protect the helper module which would not be unloaded.

Now there are two caller nf_conntrack_helper_try_module_get and
ctnetlink_create_expect which don't hold rcu lock. And the other
callers left like ctnetlink_change_helper, ctnetlink_create_conntrack,
and ctnetlink_glue_attach_expect, they already hold the rcu lock
or spin_lock_bh.

Remove the rcu lock in functions nf_ct_helper_expectfn_find_by_name
and nf_ct_helper_expectfn_find_by_symbol. Because they return one pointer
which needs rcu lock, so their caller should hold the rcu lock, not in
these two functions.

Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: using bit to represent the ct event

Otherwise, creating a new conntrack via nfnetlink:
# conntrack -I -p udp -s 1.1.1.1 -d 2.2.2.2 -t 10 --sport 10 --dport 20

will emit the wrong ct events(where UPDATE should be NEW):
# conntrack -E
[UPDATE] udp 17 10 src=1.1.1.1 dst=2.2.2.2 sport=10 dport=20
[UNREPLIED] src=2.2.2.2 dst=1.1.1.1 sport=20 dport=10 mark=0

Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: Add nfnl_msg_type() helper function

Add and use nfnl_msg_type() function to replace opencoded nfnetlink
message type. I suggested this change, Arushi Singhal made an initial
patch to address this but was missing several spots.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: Expectations must have a conntrack helper area

The expect check function __nf_ct_expect_check() asks the master_help is
necessary. So it is unnecessary to go ahead in ctnetlink_alloc_expect
when there is no help.

Actually the commit bc01befdcf3e ("netfilter: ctnetlink: add support for
user-space expectation helpers") permits ctnetlink create one expect
even though there is no master help. But the latter commit 3d058d7bc2c5
("netfilter: rework user-space expectation helper support") disables it
again.

Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: invoke synchronize_rcu after set the _hook_ to NULL

Otherwise, another CPU may access the invalid pointer. For example:
CPU0 CPU1
- rcu_read_lock();
- pfunc = _hook_;
_hook_ = NULL; -
mod unload -
- pfunc(); // invalid, panic
- rcu_read_unlock();

So we must call synchronize_rcu() to wait the rcu reader to finish.

Also note, in nf_nat_snmp_basic_fini, synchronize_rcu() will be invoked
by later nf_conntrack_helper_unregister, but I'm inclined to add a
explicit synchronize_rcu after set the nf_nat_snmp_hook to NULL. Depend
on such obscure assumptions is not a good idea.

Last, in nfnetlink_cttimeout, we use kfree_rcu to free the time object,
so in cttimeout_exit, invoking rcu_barrier() is not necessary at all,
remove it too.

Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: refcounter conversions

refcount_t type and corresponding API (see include/linux/refcount.h)
should be used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: Fix regression in CTA_HELP processing

Prior to Linux 4.4, it was usually harmless to send a CTA_HELP attribute
containing the name of the current helper. That is no longer the case:
as of Linux 4.4, if ctnetlink_change_helper() returns an error from
the ct->master check, processing of the request will fail, skipping the
NFQA_EXP attribute (if present).

This patch changes the behavior to improve compatibility with user
programs that expect the kernel interface to work the way it did prior
to Linux 4.4. If a user program specifies CTA_HELP but the argument
matches the current conntrack helper name, ignore it instead of generating
an error.

Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: Fix regression in CTA_STATUS processing

The libnetfilter_conntrack userland library always sets IPS_CONFIRMED
when building a CTA_STATUS attribute. If this toggles the bit from
0->1, the parser will return an error. On Linux 4.4+ this will cause any
NFQA_EXP attribute in the packet to be ignored. This breaks conntrackd's
userland helpers because they operate on unconfirmed connections.

Instead of returning -EBUSY if the user program asks to modify an
unchangeable bit, simply ignore the change.

Also, fix the logic so that user programs are allowed to clear
the bits that they are allowed to change.

Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: remove packet hotpath stats

These counters sit in hot path and do show up in perf, this is especially
true for 'found' and 'searched' which get incremented for every packet
processed.

Information like

searched=212030105
new=623431
found=333613
delete=623327

does not seem too helpful nowadays:

- on busy systems found and searched will overflow every few hours
(these are 32bit integers), other more busy ones every few days.

- for debugging there are better methods, such as iptables' trace target,
the conntrack log sysctls. Nowadays we also have perf tool.

This removes packet path stat counters except those that
are expected to be 0 (or close to 0) on a normal system, e.g.
'insert_failed' (race happened) or 'invalid' (proto tracker rejects).

The insert stat is retained for the ctnetlink case.
The found stat is retained for the tuple-is-taken check when NAT has to
determine if it needs to pick a different source address.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: evict stale entries on netlink dumps

When dumping we already have to look at the entire table, so we might
as well toss those entries whose timeout value is in the past.

We also look at every entry during resize operations.
However, eviction there is not as simple because we hold the
global resize lock so we can't evict without adding a 'expired' list
to drop from later. Considering that resizes are very rare it doesn't
seem worth doing it.

Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: get rid of conntrack timer

With stats enabled this eats 80 bytes on x86_64 per nf_conn entry, as
Eric Dumazet pointed out during netfilter workshop 2016.

Eric also says: "Another reason was the fact that Thomas was about to
change max timer range [..]" (500462a9de657f8, 'timers: Switch to
a non-cascading wheel').

Remove the timer and use a 32bit jiffies value containing timestamp until
entry is valid.

During conntrack lookup, even before doing tuple comparision, check
the timeout value and evict the entry in case it is too old.

The dying bit is used as a synchronization point to avoid races where
multiple cpus try to evict the same entry.

Because lookup is always lockless, we need to bump the refcnt once
when we evict, else we could try to evict already-dead entry that
is being recycled.

This is the standard/expected way when conntrack entries are destroyed.

Followup patches will introduce garbage colliction via work queue
and further places where we can reap obsoleted entries (e.g. during
netlink dumps), this is needed to avoid expired conntracks from hanging
around for too long when lookup rate is low after a busy period.

Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: use_nf_conn_expires helper in more places

... so we don't need to touch all of these places when we get rid of the
timer in nf_conn.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: reject new conntrack request with different l4proto

Currently, user can add a conntrack with different l4proto via nfnetlink.
For example, original tuple is TCP while reply tuple is SCTP. This is
invalid combination, we should report EINVAL to userspace.

Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nfnetlink_queue: fix memory leak when attach expectation successfully

User can use NFQA_EXP to attach expectations to conntracks, but we
forget to put back nf_conntrack_expect when it is inserted successfully,
i.e. in this normal case, expect's use refcnt will be 3. So even we
unlink it and put it back later, the use refcnt is still 1, then the
memory will be leaked forever.

Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: support a fixed size of 128 distinct labels

The conntrack label extension is currently variable-sized, e.g. if
only 2 labels are used by iptables rules then the labels->bits[] array
will only contain one element.

We track size of each label storage area in the 'words' member.

But in nftables and openvswitch we always have to ask for worst-case
since we don't know what bit will be used at configuration time.

As most arches are 64bit we need to allocate 24 bytes in this case:

struct nf_conn_labels {
u8 words; /* 0 1 */
/* XXX 7 bytes hole, try to pack */
long unsigned bits[2]; /* 8 24 */

Make bits a fixed size and drop the words member, it simplifies
the code and only increases memory requirements on x86 when
less than 64bit labels are required.

We still only allocate the extension if its needed.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: use a single expectation table for all namespaces

We already include netns address in the hash and compare the netns pointers
during lookup, so even if namespaces have overlapping addresses entries
will be spread across the expectation table.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: check netns when walking expect hash

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: use a single hashtable for all namespaces

We already include netns address in the hash and compare the netns pointers
during lookup, so even if namespaces have overlapping addresses entries
will be spread across the table.

Assuming 64k bucket size, this change saves 0.5 mbyte per namespace on a
64bit system.

NAT bysrc and expectation hash is still per namespace, those will
changed too soon.

Future patch will also make conntrack object slab cache global again.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: check netns when comparing conntrack objects

Once we place all conntracks in the same hash table we must also compare
the netns pointer to skip conntracks that belong to a different namespace.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

libnl: nla_put_be64(): align on a 64-bit area

nla_data() is now aligned on a 64-bit area.

A temporary version (nla_put_be64_32bit()) is added for nla_put_net64().
This function is removed in the next patch.

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

netfilter: ctnetlink: restore inlining for netlink message size calculation

Calm down gcc warnings:

net/netfilter/nf_conntrack_netlink.c:529:15: warning: 'ctnetlink_proto_size' defined but not used [-Wunused-function]
static size_t ctnetlink_proto_size(const struct nf_conn *ct)
^
net/netfilter/nf_conntrack_netlink.c:546:15: warning: 'ctnetlink_acct_size' defined but not used [-Wunused-function]
static size_t ctnetlink_acct_size(const struct nf_conn *ct)
^
net/netfilter/nf_conntrack_netlink.c:556:12: warning: 'ctnetlink_secctx_size' defined but not used [-Wunused-function]
static int ctnetlink_secctx_size(const struct nf_conn *ct)
^
net/netfilter/nf_conntrack_netlink.c:572:15: warning: 'ctnetlink_timestamp_size' defined but not used [-Wunused-function]
static size_t ctnetlink_timestamp_size(const struct nf_conn *ct)
^

So gcc compiles them out when CONFIG_NF_CONNTRACK_EVENTS and
CONFIG_NETFILTER_NETLINK_GLUE_CT are not set.

Fixes: 4054ff45454a9a4 ("netfilter: ctnetlink: remove unnecessary inlining")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>

netfilter: ctnetlink: remove unnecessary inlining

Many of these functions are called from control plane path. Move
ctnetlink_nlmsg_size() under CONFIG_NF_CONNTRACK_EVENTS to avoid a
compilation warning when CONFIG_NF_CONNTRACK_EVENTS=n.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_conntrack: use safer way to lock all buckets

When we need to lock all buckets in the connection hashtable we'd attempt to
lock 1024 spinlocks, which is way more preemption levels than supported by
the kernel. Furthermore, this behavior was hidden by checking if lockdep is
enabled, and if it was - use only 8 buckets(!).

Fix this by using a global lock and synchronize all buckets on it when we
need to lock them all. This is pretty heavyweight, but is only done when we
need to resize the hashtable, and that doesn't happen often enough (or at all).

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nfnetlink: pass down netns pointer to call() and call_rcu()

Adapt callsites to avoid recurrent lookup of the netns pointer.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: add const qualifier to nfnl_hook.get_ct

get_ct as is and will not update its skb argument, and users of
nfnl_ct_hook is currently only nfqueue, we can add const qualifier.

Signed-off-by: Ken-ichirou MATSUZAWA <chamas@h4.dion.ne.jp>

netfilter: Kconfig rename QUEUE_CT to GLUE_CT

Conntrack information attaching infrastructure is now generic and
update it's name to use `glue' in previous patch. This patch updates
Kconfig symbol name and adding NF_CT_NETLINK dependency.

Signed-off-by: Ken-ichirou MATSUZAWA <chamas@h4.dion.ne.jp>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nfnetlink_queue: rename related to nfqueue attaching conntrack info

The idea of this series of patch is to attach conntrack information to
nflog like nfqueue has already done. nfqueue conntrack info attaching
basis is generic, rename those names to generic one, glue.

Signed-off-by: Ken-ichirou MATSUZAWA <chamas@h4.dion.ne.jp>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nfnetlink_queue: get rid of nfnetlink_queue_ct.c

The original intention was to avoid dependencies between nfnetlink_queue and
conntrack without ifdef pollution. However, we can achieve this by moving the
conntrack dependent code into ctnetlink and keep some glue code to access the
nfq_ct indirection from nfqueue.

After this patch, the nfq_ct indirection is always compiled in the netfilter
core to avoid polluting nfqueue with ifdefs. Thus, if nf_conntrack is not
compiled this results in only 8-bytes of memory waste in x86_64.

This patch also adds ctnetlink_nfqueue_seqadj() to avoid that the nf_conn
structure layout if exposed to nf_queue, which creates another dependency with
nf_conntrack at compilation time.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_conntrack: add efficient mark to zone mapping

This work adds the possibility of deriving the zone id from the skb->mark
field in a scalable manner. This allows for having only a single template
serving hundreds/thousands of different zones, for example, instead of the
need to have one match for each zone as an extra CT jump target.

Note that we'd need to have this information attached to the template as at
the time when we're trying to lookup a possible ct object, we already need
to know zone information for a possible match when going into
__nf_conntrack_find_get(). This work provides a minimal implementation for
a possible mapping.

In order to not add/expose an extra ct->status bit, the zone structure has
been extended to carry a flag for deriving the mark.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_conntrack: add direction support for zones

This work adds a direction parameter to netfilter zones, so identity
separation can be performed only in original/reply or both directions
(default). This basically opens up the possibility of doing NAT with
conflicting IP address/port tuples from multiple, isolated tenants
on a host (e.g. from a netns) without requiring each tenant to NAT
twice resp. to use its own dedicated IP address to SNAT to, meaning
overlapping tuples can be made unique with the zone identifier in
original direction, where the NAT engine will then allocate a unique
tuple in the commonly shared default zone for the reply direction.
In some restricted, local DNAT cases, also port redirection could be
used for making the reply traffic unique w/o requiring SNAT.

The consensus we've reached and discussed at NFWS and since the initial
implementation [1] was to directly integrate the direction meta data
into the existing zones infrastructure, as opposed to the ct->mark
approach we proposed initially.

As we pass the nf_conntrack_zone object directly around, we don't have
to touch all call-sites, but only those, that contain equality checks
of zones. Thus, based on the current direction (original or reply),
we either return the actual id, or the default NF_CT_DEFAULT_ZONE_ID.
CT expectations are direction-agnostic entities when expectations are
being compared among themselves, so we can only use the identifier
in this case.

Note that zone identifiers can not be included into the hash mix
anymore as they don't contain a "stable" value that would be equal
for both directions at all times, f.e. if only zone->id would
unconditionally be xor'ed into the table slot hash, then replies won't
find the corresponding conntracking entry anymore.

If no particular direction is specified when configuring zones, the
behaviour is exactly as we expect currently (both directions).

Support has been added for the CT netlink interface as well as the
x_tables raw CT target, which both already offer existing interfaces
to user space for the configuration of zones.

Below a minimal, simplified collision example (script in [2]) with
netperf sessions:

+--- tenant-1 ---+ mark := 1
| netperf |--+
+----------------+ | CT zone := mark [ORIGINAL]
[ip,sport] := X +--------------+ +--- gateway ---+
| mark routing |--| SNAT |-- ... +
+--------------+ +---------------+ |
+--- tenant-2 ---+ | ~~~|~~~
| netperf |--+ +-----------+ |
+----------------+ mark := 2 | netserver |------ ... +
[ip,sport] := X +-----------+
[ip,port] := Y
On the gateway netns, example:

iptables -t raw -A PREROUTING -j CT --zone mark --zone-dir ORIGINAL
iptables -t nat -A POSTROUTING -o <dev> -j SNAT --to-source <ip> --random-fully

iptables -t mangle -A PREROUTING -m conntrack --ctdir ORIGINAL -j CONNMARK --save-mark
iptables -t mangle -A POSTROUTING -m conntrack --ctdir REPLY -j CONNMARK --restore-mark

conntrack dump from gateway netns:

netperf -H 10.1.1.2 -t TCP_STREAM -l60 -p12865,5555 from each tenant netns

tcp 6 431995 ESTABLISHED src=40.1.1.1 dst=10.1.1.2 sport=5555 dport=12865 zone-orig=1
src=10.1.1.2 dst=10.1.1.1 sport=12865 dport=1024
[ASSURED] mark=1 secctx=system_u:object_r:unlabeled_t:s0 use=1

tcp 6 431994 ESTABLISHED src=40.1.1.1 dst=10.1.1.2 sport=5555 dport=12865 zone-orig=2
src=10.1.1.2 dst=10.1.1.1 sport=12865 dport=5555
[ASSURED] mark=2 secctx=system_u:object_r:unlabeled_t:s0 use=1

tcp 6 299 ESTABLISHED src=40.1.1.1 dst=10.1.1.2 sport=39438 dport=33768 zone-orig=1
src=10.1.1.2 dst=10.1.1.1 sport=33768 dport=39438
[ASSURED] mark=1 secctx=system_u:object_r:unlabeled_t:s0 use=1

tcp 6 300 ESTABLISHED src=40.1.1.1 dst=10.1.1.2 sport=32889 dport=40206 zone-orig=2
src=10.1.1.2 dst=10.1.1.1 sport=40206 dport=32889
[ASSURED] mark=2 secctx=system_u:object_r:unlabeled_t:s0 use=2

Taking this further, test script in [2] creates 200 tenants and runs
original-tuple colliding netperf sessions each. A conntrack -L dump in
the gateway netns also confirms 200 overlapping entries, all in ESTABLISHED
state as expected.

I also did run various other tests with some permutations of the script,
to mention some: SNAT in random/random-fully/persistent mode, no zones (no
overlaps), static zones (original, reply, both directions), etc.

[1] http://thread.gmane.org/gmane.comp.security.firewalls.netfilter.devel/57412/
[2] https://paste.fedoraproject.org/242835/65657871/

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_conntrack: push zone object into functions

This patch replaces the zone id which is pushed down into functions
with the actual zone object. It's a bigger one-time change, but
needed for later on extending zones with a direction parameter, and
thus decoupling this additional information from all call-sites.

No functional changes in this patch.

The default zone becomes a global const object, namely nf_ct_zone_dflt
and will be returned directly in various cases, one being, when there's
f.e. no zoning support.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: put back references to master ct and expect objects

We have to put back the references to the master conntrack and the expectation
that we just created, otherwise we'll leak them.

Fixes: 0ef71ee1a5b9 ("netfilter: ctnetlink: refactor ctnetlink_create_expect")
Reported-by: Tim Wiess <Tim.Wiess@watchguard.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: Flush connections with a given mark

This patch adds support for selective flushing of conntrack mappings.
By adding CTA_MARK and CTA_MARK_MASK to a delete-message, the mark (and
mask) is checked before a connection is deleted while flushing.

Configuring the flush is moved out of ctnetlink_del_conntrack(), and
instead of calling nf_conntrack_flush_report(), we always call
nf_ct_iterate_cleanup(). This enables us to only make one call from the
new ctnetlink_flush_conntrack() and makes it easy to add more filter
parameters.

Filtering is done in the ctnetlink_filter_match()-function, which is
also called from ctnetlink_dump_table(). ctnetlink_dump_filter has been
renamed ctnetlink_filter, to indicated that it is no longer only used
when dumping conntrack entries.

Moreover, reject mark filters with -EOPNOTSUPP if no ct mark support is
available.

Signed-off-by: Kristian Evensen <kristian.evensen@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net: use ktime_get_ns() and ktime_get_real_ns() helpers

ktime_get_ns() replaces ktime_to_ns(ktime_get())

ktime_get_real_ns() replaces ktime_to_ns(ktime_get_real())

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

netfilter: ctnetlink: remove null test before kfree

Fix checkpatch warning:
WARNING: kfree(NULL) is safe this check is probably not required

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: add zone size to length

Signed-off-by: Ken-ichirou MATSUZAWA <chamas@h4.dion.ne.jp>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: fix refcnt leak in dying/unconfirmed list dumper

'last' keeps track of the ct that had its refcnt bumped during previous
dump cycle. Thus it must not be overwritten until end-of-function.

Another (unrelated, theoretical) issue: Don't attempt to bump refcnt of a conntrack
whose reference count is already 0. Such conntrack is being destroyed
right now, its memory is freed once we release the percpu dying spinlock.

Fixes: b7779d06 ('netfilter: conntrack: spinlock per cpu to protect special lists.')
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: fix dumping of dying/unconfirmed conntracks

The dumping prematurely stops, it seems the callback argument that
indicates that all entries have been dumped is set after iterating
on the first cpu list. The dumping also may stop before the entire
per-cpu list content is also dumped.

With this patch, conntrack -L dying now shows the dying list content
again.

Fixes: b7779d06 ("netfilter: conntrack: spinlock per cpu to protect special lists.")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: don't add null bindings if no nat requested

commit 0eba801b64cc8284d9024c7ece30415a2b981a72 tried to fix a race
where nat initialisation can happen after ctnetlink-created conntrack
has been created.

However, it causes the nat module(s) to be loaded needlessly on
systems that are not using NAT.

Fortunately, we do not have to create null bindings in that case.

conntracks injected via ctnetlink always have the CONFIRMED bit set,
which prevents addition of the nat extension in nf_nat_ipv4/6_fn().

We only need to make sure that either no nat extension is added
or that we've created both src and dst manips.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: remove central spinlock nf_conntrack_lock

nf_conntrack_lock is a monolithic lock and suffers from huge contention
on current generation servers (8 or more core/threads).

Perf locking congestion is clear on base kernel:

- 72.56% ksoftirqd/6 [kernel.kallsyms] [k] _raw_spin_lock_bh
- _raw_spin_lock_bh
+ 25.33% init_conntrack
+ 24.86% nf_ct_delete_from_lists
+ 24.62% __nf_conntrack_confirm
+ 24.38% destroy_conntrack
+ 0.70% tcp_packet
+ 2.21% ksoftirqd/6 [kernel.kallsyms] [k] fib_table_lookup
+ 1.15% ksoftirqd/6 [kernel.kallsyms] [k] __slab_free
+ 0.77% ksoftirqd/6 [kernel.kallsyms] [k] inet_getpeer
+ 0.70% ksoftirqd/6 [nf_conntrack] [k] nf_ct_delete
+ 0.55% ksoftirqd/6 [ip_tables] [k] ipt_do_table

This patch change conntrack locking and provides a huge performance
improvement. SYN-flood attack tested on a 24-core E5-2695v2(ES) with
10Gbit/s ixgbe (with tool trafgen):

Base kernel: 810.405 new conntrack/sec
After patch: 2.233.876 new conntrack/sec

Notice other floods attack (SYN+ACK or ACK) can easily be deflected using:
# iptables -A INPUT -m state --state INVALID -j DROP
# sysctl -w net/netfilter/nf_conntrack_tcp_loose=0

Use an array of hashed spinlocks to protect insertions/deletions of
conntracks into the hash table. 1024 spinlocks seem to give good
results, at minimal cost (4KB memory). Due to lockdep max depth,
1024 becomes 8 if CONFIG_LOCKDEP=y

The hash resize is a bit tricky, because we need to take all locks in
the array. A seqcount_t is used to synchronize the hash table users
with the resizing process.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: seperate expect locking from nf_conntrack_lock

Netfilter expectations are protected with the same lock as conntrack
entries (nf_conntrack_lock). This patch split out expectations locking
to use it's own lock (nf_conntrack_expect_lock).

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: spinlock per cpu to protect special lists.

One spinlock per cpu to protect dying/unconfirmed/template special lists.
(These lists are now per cpu, a bit like the untracked ct)
Add a @cpu field to nf_conn, to make sure we hold the appropriate
spinlock at removal time.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nft_ct: labels get support

This also adds NF_CT_LABELS_MAX_SIZE so it can be re-used
as BUILD_BUG_ON in nft_ct.

At this time, nft doesn't yet support writing to the label area;
when this changes the label->words handling needs to be moved
out of xt_connlabel.c into nf_conntrack_labels.c.

Also removes a useless run-time check: words cannot grow beyond
4 (32 bit) or 2 (64bit) since xt_connlabel enforces a maximum of
128 labels.

Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: force null nat binding on insert

Quoting Andrey Vagin:
When a conntrack is created by kernel, it is initialized (sets
IPS_{DST,SRC}_NAT_DONE_BIT bits in nf_nat_setup_info) and only then it
is added in hashes (__nf_conntrack_hash_insert), so one conntract
can't be initialized from a few threads concurrently.

ctnetlink can add an uninitialized conntrack (w/o
IPS_{DST,SRC}_NAT_DONE_BIT) in hashes, then a few threads can look up
this conntrack and start initialize it concurrently. It's dangerous,
because BUG can be triggered from nf_nat_setup_info.

Fix this race by always setting up nat, even if no CTA_NAT_ attribute
was requested before inserting the ct into the hash table. In absence
of CTA_NAT_ attribute, a null binding is created.

This alters current behaviour: Before this patch, the first packet
matching the newly injected conntrack would be run through the nat
table since nf_nat_initialized() returns false. IOW, this forces
ctnetlink users to specify the desired nat transformation on ct
creation time.

Thanks for Florian Westphal, this patch is based on his original
patch to address this problem, including this patch description.

Reported-By: Andrey Vagin <avagin@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Florian Westphal <fw@strlen.de>

netfilter: ctnetlink: honor CTA_MARK_MASK when setting ctmark

Useful to only set a particular range of the conntrack mark while
leaving exisiting parts of the value alone, e.g. when setting
conntrack marks via NFQUEUE.

Follows same scheme as MARK/CONNMARK targets, i.e. the mask defines
those bits that should be altered. No mask is equal to '~0', ie.
the old value is replaced by new one.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: account both directions in one step

With the intent to dump other accounting data later.
This patch is a cleanup.

Signed-off-by: Holger Eitzenberger <holger@eitzenberger.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: introduce nf_conn_acct structure

Encapsulate counters for both directions into nf_conn_acct. During
that process also consistently name pointers to the extend 'acct',
not 'counters'. This patch is a cleanup.

Signed-off-by: Holger Eitzenberger <holger@eitzenberger.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: fix uninitialized variable

net/netfilter/nf_conntrack_netlink.c: In function 'ctnetlink_nfqueue_attach_expect':
'helper' may be used uninitialized in this function

It was only initialized in if CTA_EXPECT_HELP_NAME attribute was
present, it must be NULL otherwise.

Problem added recently in bd077937
(netfilter: nfnetlink_queue: allow to attach expectations to conntracks).

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_conntrack: make sequence number adjustments usuable without NAT

Split out sequence number adjustments from NAT and move them to the conntrack
core to make them usable for SYN proxying. The sequence number adjustment
information is moved to a seperate extend. The extend is added to new
conntracks when a NAT mapping is set up for a connection using a helper.

As a side effect, this saves 24 bytes per connection with NAT in the common
case that a connection does not have a helper assigned.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Tested-by: Martin Topholm <mph@one.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nfnetlink_queue: allow to attach expectations to conntracks

This patch adds the capability to attach expectations via nfnetlink_queue.
This is required by conntrack helpers that trigger expectations based on
the first packet seen like the TFTP and the DHCPv6 user-space helpers.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: refactor ctnetlink_create_expect

This patch refactors ctnetlink_create_expect by spliting it in two
chunks. As a result, we have a new function ctnetlink_alloc_expect
to allocate and to setup the expectation from ctnetlink.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_conntrack: remove duplicate code in ctnetlink

ctnetlink contains copy-paste code from death_by_timeout. In order to
avoid changing both places in upcoming event delivery patch,
export death_by_timeout functionality and use it in the ctnetlink code.

Based on earlier patch from Pablo Neira.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: send event when conntrack label was modified

commit 0ceabd83875b72a29f33db4ab703d6ba40ea4c58
(netfilter: ctnetlink: deliver labels to userspace) sets the event bit
when we raced with another packet, instead of raising the event bit
when the label bit is set for the first time.

commit 9b21f6a90924dfe8e5e686c314ddb441fb06501e
(netfilter: ctnetlink: allow userspace to modify labels) forgot to update
the event mask in the "conntrack already exists" case.

Both issues result in CTA_LABELS attribute not getting included in the
conntrack event.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: check return code from nla_parse_tested

These are the only calls under net/ that do not check nla_parse_nested()
for its error code, but simply continue execution. If parsing of netlink
attributes fails, we should return with an error instead of continuing.
In nearly all of these calls we have a policy attached, that is being
type verified during nla_parse_nested(), which we would miss checking
for otherwise.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: allow to dump expectation per master conntrack

This patch adds the ability to dump all existing expectations
per master conntrack.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

hlist: drop the node parameter from iterators

I'm not sure why, but the hlist for each entry iterators were conceived

list_for_each_entry(pos, head, member)

The hlist ones were greedy and wanted an extra parameter:

hlist_for_each_entry(tpos, pos, head, member)

Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.

Besides the semantic patch, there was some manual work required:

- Fix up the actual hlist iterators in linux/list.h
- Fix up the declaration of other iterators based on the hlist ones.
- A very small amount of places were using the 'node' parameter, this
was modified to use 'obj->member' instead.
- Coccinelle didn't handle the hlist_for_each_entry_safe iterator
properly, so those had to be fixed up manually.

The semantic patch which is mostly the work of Peter Senna Tschudin is here:

@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;

type T;
expression a,c,d,e;
identifier b;
statement S;
@@

-T b;
<+... when != b
(
hlist_for_each_entry(a,
- b,
c, d) S
|
hlist_for_each_entry_continue(a,
- b,
c) S
|
hlist_for_each_entry_from(a,
- b,
c) S
|
hlist_for_each_entry_rcu(a,
- b,
c, d) S
|
hlist_for_each_entry_rcu_bh(a,
- b,
c, d) S
|
hlist_for_each_entry_continue_rcu_bh(a,
- b,
c) S
|
for_each_busy_worker(a, c,
- b,
d) S
|
ax25_uid_for_each(a,
- b,
c) S
|
ax25_for_each(a,
- b,
c) S
|
inet_bind_bucket_for_each(a,
- b,
c) S
|
sctp_for_each_hentry(a,
- b,
c) S
|
sk_for_each(a,
- b,
c) S
|
sk_for_each_rcu(a,
- b,
c) S
|
sk_for_each_from
-(a, b)
+(a)
S
+ sk_for_each_from(a) S
|
sk_for_each_safe(a,
- b,
c, d) S
|
sk_for_each_bound(a,
- b,
c) S
|
hlist_for_each_entry_safe(a,
- b,
c, d, e) S
|
hlist_for_each_entry_continue_rcu(a,
- b,
c) S
|
nr_neigh_for_each(a,
- b,
c) S
|
nr_neigh_for_each_safe(a,
- b,
c, d) S
|
nr_node_for_each(a,
- b,
c) S
|
nr_node_for_each_safe(a,
- b,
c, d) S
|
- for_each_gfn_sp(a, c, d, b) S
+ for_each_gfn_sp(a, c, d) S
|
- for_each_gfn_indirect_valid_sp(a, c, d, b) S
+ for_each_gfn_indirect_valid_sp(a, c, d) S
|
for_each_host(a,
- b,
c) S
|
for_each_host_safe(a,
- b,
c, d) S
|
for_each_mesh_entry(a,
- b,
c, d) S
)
...+>

[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: Peter Senna Tschudin <peter.senna@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

netfilter: ctnetlink: don't permit ct creation with random tuple

Userspace can cause kernel panic by not specifying orig/reply
tuple: kernel will create a tuple with random stack values.

Problem is that tuple.dst.dir will be random, too, which
causes nf_ct_tuplehash_to_ctrack() to return garbage.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@gnumonks.org>

netfilter: nfnetlink: add mutex per subsystem

This patch replaces the global lock to one lock per subsystem.
The per-subsystem lock avoids that processes operating
with different subsystems are synchronized.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: allow userspace to modify labels

Add the ability to set/clear labels assigned to a conntrack
via ctnetlink.

To allow userspace to only alter specific bits, Pablo suggested to add
a new CTA_LABELS_MASK attribute:

The new set of active labels is then determined via

active = (active & ~mask) ^ changeset

i.e., the mask selects those bits in the existing set that should be
changed.

This follows the same method already used by MARK and CONNMARK targets.

Omitting CTA_LABELS_MASK is the same as setting all bits in CTA_LABELS_MASK
to 1: The existing set is replaced by the one from userspace.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: deliver labels to userspace

Introduce CTA_LABELS attribute to send a bit-vector of currently active labels
to userspace.

Future patch will permit userspace to also set/delete active labels.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: add connlabel conntrack extension

similar to connmarks, except labels are bit-based; i.e.
all labels may be attached to a flow at the same time.

Up to 128 labels are supported. Supporting more labels
is possible, but requires increasing the ct offset delta
from u8 to u16 type due to increased extension sizes.

Mapping of bit-identifier to label name is done in userspace.

The extension is enabled at run-time once "-m connlabel" netfilter
rules are added.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: fix leak in error path of ctnetlink_create_expect

This patch fixes a leak in one of the error paths of
ctnetlink_create_expect if no helper and no timeout is specified.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: nla_policy updates

Add stricter checking for a few attributes.
Note that these changes don't fix any bug in the current code base.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: dump entries from the dying and unconfirmed lists

This patch adds a new operation to dump the content of the dying and
unconfirmed lists.

Under some situations, the global conntrack counter can be inconsistent
with the number of entries that we can dump from the conntrack table.
The way to resolve this is to allow dumping the content of the unconfirmed
and dying lists, so far it was not possible to look at its content.

This provides some extra instrumentation to resolve problematic situations
in which anyone suspects memory leaks.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_conntrack: improve nf_conn object traceability

This patch modifies the conntrack subsystem so that all existing
allocated conntrack objects can be found in any of the following
places:

* the hash table, this is the typical place for alive conntrack objects.
* the unconfirmed list, this is the place for newly created conntrack objects
that are still traversing the stack.
* the dying list, this is where you can find conntrack objects that are dying
or that should die anytime soon (eg. once the destroy event is delivered to
the conntrackd daemon).

Thus, we make sure that we follow the track for all existing conntrack
objects. This patch, together with some extension of the ctnetlink interface
to dump the content of the dying and unconfirmed lists, will help in case
to debug suspected nf_conn object leaks.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_ct_ftp: add sequence tracking pickup facility for injected entries

This patch allows the FTP helper to pickup the sequence tracking from
the first packet seen. This is useful to fix the breakage of the first
FTP command after the failover while using conntrackd to synchronize
states.

The seq_aft_nl_num field in struct nf_ct_ftp_info has been shrinked to
16-bits (enough for what it does), so we can use the remaining 16-bits
to store the flags while using the same size for the private FTP helper
data.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: fix module auto-load in ctnetlink_parse_nat

(c7232c9 netfilter: add protocol independent NAT core) added
incorrect locking for the module auto-load case in ctnetlink_parse_nat.

That function is always called from ctnetlink_create_conntrack which
requires no locking.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netlink: Rename pid to portid to avoid confusion

It is a frequent mistake to confuse the netlink port identifier with a
process identifier. Try to reduce this confusion by renaming fields
that hold port identifiers portid instead of pid.

I have carefully avoided changing the structures exported to
userspace to avoid changing the userspace API.

I have successfully built an allyesconfig kernel with this change.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

netfilter: ctnetlink: fix error return code in init path

Initialize return variable before exiting on an error path.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
(
if@p1 (\(ret < 0\|ret != 0\))
{ ... return ret; }
|
ret@p1 = 0
)
... when != ret = e1
when != &ret
*if(...)
{
... when != ret = e2
when forall
return ret;
}

// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: add protocol independent NAT core

Convert the IPv4 NAT implementation to a protocol independent core and
address family specific modules.

Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: ctnetlink: fix missing locking while changing conntrack from nfqueue

Since 9cb017665 netfilter: add glue code to integrate nfnetlink_queue and
ctnetlink, we can modify the conntrack entry via nfnl_queue. However, the
change of the conntrack entry via nfnetlink_queue requires appropriate
locking to avoid concurrent updates.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: add new messages to obtain statistics

This patch adds the following messages to ctnetlink:

IPCTNL_MSG_CT_GET_STATS_CPU
IPCTNL_MSG_CT_GET_STATS
IPCTNL_MSG_EXP_GET_STATS_CPU

To display connection tracking system per-cpu and global statistics.

This provides a replacement for the following /proc interfaces:

/proc/net/stat/nf_conntrack
/proc/sys/net/netfilter/nf_conntrack_count

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: fix compilation with NF_CONNTRACK_EVENTS=n

This patch fixes compilation with NF_CONNTRACK_EVENTS=n and
NETFILTER_NETLINK_QUEUE_CT=y.

I'm leaving all those static inline functions that calculate the size
of the event message out of the ifdef area of NF_CONNTRACK_EVENTS since
they will not be included by gcc in case they are unused.

Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nfnetlink_queue: fix compilation with CONFIG_NF_NAT=m and CONFIG_NF_CT_NETLINK=y

LD init/built-in.o
net/built-in.o:(.data+0x4408): undefined reference to `nf_nat_tcp_seq_adjust'
make: *** [vmlinux] Error 1

This patch adds a new pointer hook (nfq_ct_nat_hook) similar to other existing
in Netfilter to solve our complicated configuration dependencies.

Reported-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nfnetlink_queue: fix compilation with NF_CONNTRACK disabled

In "9cb0176 netfilter: add glue code to integrate nfnetlink_queue and ctnetlink"
the compilation with NF_CONNTRACK disabled is broken. This patch fixes this
issue.

I have moved the conntrack part into nfnetlink_queue_ct.c to avoid
peppering the entire nfnetlink_queue.c code with ifdefs.

I also needed to rename nfnetlink_queue.c to nfnetlink_queue_pkt.c
to update the net/netfilter/Makefile to support conditional compilation
of the conntrack integration.

This patch also adds CONFIG_NETFILTER_QUEUE_CT in case you want to explicitly
disable the integration between nf_conntrack and nfnetlink_queue.

Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: fix NULL dereference while trying to change helper

The patch 1afc56794e03: "netfilter: nf_ct_helper: implement variable
length helper private data" from Jun 7, 2012, leads to the following
Smatch complaint:

net/netfilter/nf_conntrack_netlink.c:1231 ctnetlink_change_helper()
error: we previously assumed 'help->helper' could be null (see line 1228)

This NULL dereference can be triggered with the following sequence:

1) attach the helper for first time when the conntrack is created.
2) remove the helper module or detach the helper from the conntrack
via ctnetlink.
3) attach helper again (the same or different one, no matter) to the
that existing conntrack again via ctnetlink.

This patch fixes the problem by removing the use case that allows you
to re-assign again a helper for one conntrack entry via ctnetlink since
I cannot find any practical use for it.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: add CTA_HELP_INFO attribute

This attribute can be used to modify and to dump the internal
protocol information.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nfnetlink_queue: add NAT TCP sequence adjustment if packet mangled

User-space programs that receive traffic via NFQUEUE may mangle packets.
If NAT is enabled, this usually puzzles sequence tracking, leading to
traffic disruptions.

With this patch, nfnl_queue will make the corresponding NAT TCP sequence
adjustment if:

1) The packet has been mangled,
2) the NFQA_CFG_F_CONNTRACK flag has been set, and
3) NAT is detected.

There are some records on the Internet complaning about this issue:
http://stackoverflow.com/questions/260757/packet-mangling-utilities-besides-iptables

By now, we only support TCP since we have no helpers for DCCP or SCTP.
Better to add this if we ever have some helper over those layer 4 protocols.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: add glue code to integrate nfnetlink_queue and ctnetlink

This patch allows you to include the conntrack information together
with the packet that is sent to user-space via NFQUEUE.

Previously, there was no integration between ctnetlink and
nfnetlink_queue. If you wanted to access conntrack information
from your libnetfilter_queue program, you required to query
ctnetlink from user-space to obtain it. Thus, delaying the packet
processing even more.

Including the conntrack information is optional, you can set it
via NFQA_CFG_F_CONNTRACK flag with the new NFQA_CFG_FLAGS attribute.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_ct_helper: implement variable length helper private data

This patch uses the new variable length conntrack extensions.

Instead of using union nf_conntrack_help that contain all the
helper private data information, we allocate variable length
area to store the private helper data.

This patch includes the modification of all existing helpers.
It also includes a couple of include header to avoid compilation
warnings.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_ct_expect: partially implement ctnetlink_change_expect

This refreshes the "timeout" attribute in existing expectations if one is
given.

The use case for this would be for userspace helpers to extend the lifetime
of the expectation when requested, as this is not possible right now
without deleting/recreating the expectation.

I use this specifically for forwarding DCERPC traffic through:

DCERPC has a port mapper daemon that chooses a (seemingly) random port for
future traffic to go to. We expect this traffic (with a reasonable
timeout), but sometimes the port mapper will tell the client to continue
using the same port. This allows us to extend the expectation accordingly.

Signed-off-by: Kelvie Wong <kelvie@ieee.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

nf_conntrack_netlink: Stop using NLA_PUT*().

These macros contain a hidden goto, and are thus extremely error
prone and make code hard to audit.

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

netfilter: ctnetlink: fix race between delete and timeout expiration

Kerin Millar reported hardlockups while running `conntrackd -c'
in a busy firewall. That system (with several processors) was
acting as backup in a primary-backup setup.

After several tries, I found a race condition between the deletion
operation of ctnetlink and timeout expiration. This patch fixes
this problem.

Tested-by: Kerin Millar <kerframil@gmail.com>
Reported-by: Kerin Millar <kerframil@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

netfilter: ctnetlink: fix lockep splats

net/netfilter/nf_conntrack_proto.c:70 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 1, debug_locks = 0
3 locks held by conntrack/3235:
nfnl_lock+0x17/0x20
netlink_dump+0x32/0x240
ctnetlink_dump_table+0x3e/0x170 [nf_conntrack_netlink]

stack backtrace:
Pid: 3235, comm: conntrack Tainted: G W 3.2.0+ #511
Call Trace:
[<ffffffff8108ce45>] lockdep_rcu_suspicious+0xe5/0x100
[<ffffffffa00ec6e1>] __nf_ct_l4proto_find+0x81/0xb0 [nf_conntrack]
[<ffffffffa0115675>] ctnetlink_fill_info+0x215/0x5f0 [nf_conntrack_netlink]
[<ffffffffa0115dc1>] ctnetlink_dump_table+0xd1/0x170 [nf_conntrack_netlink]
[<ffffffff815fbdbf>] netlink_dump+0x7f/0x240
[<ffffffff81090f9d>] ? trace_hardirqs_on+0xd/0x10
[<ffffffff815fd34f>] netlink_dump_start+0xdf/0x190
[<ffffffffa0111490>] ? ctnetlink_change_nat_seq_adj+0x160/0x160 [nf_conntrack_netlink]
[<ffffffffa0115cf0>] ? ctnetlink_get_conntrack+0x2a0/0x2a0 [nf_conntrack_netlink]
[<ffffffffa0115ad9>] ctnetlink_get_conntrack+0x89/0x2a0 [nf_conntrack_netlink]
[<ffffffff81603a47>] nfnetlink_rcv_msg+0x467/0x5f0
[<ffffffff81603a7c>] ? nfnetlink_rcv_msg+0x49c/0x5f0
[<ffffffff81603922>] ? nfnetlink_rcv_msg+0x342/0x5f0
[<ffffffff81071b21>] ? get_parent_ip+0x11/0x50
[<ffffffff816035e0>] ? nfnetlink_subsys_register+0x60/0x60
[<ffffffff815fed49>] netlink_rcv_skb+0xa9/0xd0
[<ffffffff81603475>] nfnetlink_rcv+0x15/0x20
[<ffffffff815fe70e>] netlink_unicast+0x1ae/0x1f0
[<ffffffff815fea16>] netlink_sendmsg+0x2c6/0x320
[<ffffffff815b2a87>] sock_sendmsg+0x117/0x130
[<ffffffff81125093>] ? might_fault+0x53/0xb0
[<ffffffff811250dc>] ? might_fault+0x9c/0xb0
[<ffffffff81125093>] ? might_fault+0x53/0xb0
[<ffffffff815b5991>] ? move_addr_to_kernel+0x71/0x80
[<ffffffff815b644e>] sys_sendto+0xfe/0x130
[<ffffffff815b5c94>] ? sys_bind+0xb4/0xd0
[<ffffffff817a8a0e>] ? retint_swapgs+0xe/0x13
[<ffffffff817afcd2>] system_call_fastpath+0x16/0x1b

Reported-by: Hans Schillstrom <hans.schillstrom@ericsson.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Hans Schillstrom <hans.schillstrom@ericsson.com>

netfilter: ctnetlink: allow to set expectfn for expectations

This patch allows you to set expectfn which is specifically used
by the NAT side of most of the existing conntrack helpers.

I have added a symbol map that uses a string as key to look up for
the function that is attached to the expectation object. This is
the best solution I came out with to solve this issue.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: add NAT support for expectations

This patch adds the missing bits to create expectations that
are created in NAT setups.

netfilter: ctnetlink: allow to set expectation class

This patch allows you to set the expectation class.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: allow to set helper for new expectations

This patch allow you to set the helper for newly created
expectations based of the CTA_EXPECT_HELP_NAME attribute.
Before this, the helper set was NULL.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: remove incorrect spin_[un]lock_bh on NAT module autoload

Since 7d367e0, ctnetlink_new_conntrack is called without holding
the nf_conntrack_lock spinlock. Thus, ctnetlink_parse_nat_setup
does not require to release that spinlock anymore in the NAT module
autoload case.

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

netfilter: ctnetlink: support kernel-space dump filtering by ctmark

This patch adds CTA_MARK_MASK which, together with CTA_MARK, allows
you to selectively send conntrack entries to user-space by
returning those that match mark & mask.

With this, we can save cycles in the building and the parsing of
the entries that may be later on filtered out in user-space by using
the ctmark & mask.

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

netlink: add netlink_dump_control structure for netlink_dump_start()

Davem considers that the argument list of this interface is getting
out of control. This patch tries to address this issue following
his proposal:

struct netlink_dump_control c = { .dump = dump, .done = done, ... };

netlink_dump_start(..., &c);

Suggested by David S. Miller.

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

netfilter: ctnetlink: fix soft lockup when netlink adds new entries (v2)

Marcell Zambo and Janos Farago noticed and reported that when
new conntrack entries are added via netlink and the conntrack table
gets full, soft lockup happens. This is because the nf_conntrack_lock
is held while nf_conntrack_alloc is called, which is in turn wants
to lock nf_conntrack_lock while evicting entries from the full table.

The patch fixes the soft lockup with limiting the holding of the
nf_conntrack_lock to the minimum, where it's absolutely required.
It required to extend (and thus change) nf_conntrack_hash_insert
so that it makes sure conntrack and ctnetlink do not add the same entry
twice to the conntrack table.

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Revert "netfilter: ctnetlink: fix soft lockup when netlink adds new entries"

This reverts commit af14cca162ddcdea017b648c21b9b091e4bf1fa4.

This patch contains a race condition between packets and ctnetlink
in the conntrack addition. A new patch to fix this issue follows up.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: fix soft lockup when netlink adds new entries

Marcell Zambo and Janos Farago noticed and reported that when
new conntrack entries are added via netlink and the conntrack table
gets full, soft lockup happens. This is because the nf_conntrack_lock
is held while nf_conntrack_alloc is called, which is in turn wants
to lock nf_conntrack_lock while evicting entries from the full table.

The patch fixes the soft lockup with limiting the holding of the
nf_conntrack_lock to the minimum, where it's absolutely required.

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: revert user-space expectation helper support

This patch partially reverts:
3d058d7 netfilter: rework user-space expectation helper support
that was applied during the 3.2 development cycle.

After this patch, the tree remains just like before patch bc01bef,
that initially added the preliminary infrastructure.

I decided to partially revert this patch because the approach
that I proposed to resolve this problem is broken in NAT setups.
Moreover, a new infrastructure will be submitted for the 3.3.x
development cycle that resolve the existing issues while
providing a neat solution.

Since nobody has been seriously using this infrastructure in
user-space, the removal of this feature should affect any know
FOSS project (to my knowledge).

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net: reintroduce missing rcu_assign_pointer() calls

commit a9b3cd7f32 (rcu: convert uses of rcu_assign_pointer(x, NULL) to
RCU_INIT_POINTER) did a lot of incorrect changes, since it did a
complete conversion of rcu_assign_pointer(x, y) to RCU_INIT_POINTER(x,
y).

We miss needed barriers, even on x86, when y is not NULL.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Stephen Hemminger <shemminger@vyatta.com>
CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

netfilter: ctnetlink: fix timeout calculation

The sanity check (timeout < 0) never works; the dividend is unsigned
and so is the division, which should have been a signed division.

long timeout = (ct->timeout.expires - jiffies) / HZ;
if (timeout < 0)
timeout = 0;

This patch converts the time values to signed for the division.

Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: fix scheduling while atomic if helper is autoloaded

This patch fixes one scheduling while atomic error:

[ 385.565186] ctnetlink v0.93: registering with nfnetlink.
[ 385.565349] BUG: scheduling while atomic: lt-expect_creat/16163/0x00000200

It can be triggered with utils/expect_create included in
libnetfilter_conntrack if the FTP helper is not loaded.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: fix return value of ctnetlink_get_expect()

This fixes one bogus error that is returned to user-space:

libnetfilter_conntrack/utils# ./expect_get
TEST: get expectation (-1)(Unknown error 18446744073709551504)

This patch includes the correct handling for EAGAIN (nfnetlink
uses this error value to restart the operation after module
auto-loading).

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: get and zero operations must be atomic

The get and zero operations have to be done in an atomic context,
otherwise counters added between them will be lost.

This problem was spotted by Changli Gao while discussing the
nfacct infrastructure.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_nat: export NAT definitions to userspace

Export the NAT definitions to userspace. So far userspace (specifically,
iptables) has been copying the headers files from include/net. Also
rename some structures and definitions in preparation for IPv6 NAT.
Since these have never been officially exported, this doesn't affect
existing userspace code.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: rework user-space expectation helper support

This partially reworks bc01befdcf3e40979eb518085a075cbf0aacede0
which added userspace expectation support.

This patch removes the nf_ct_userspace_expect_list since now we
force to use the new iptables CT target feature to add the helper
extension for conntracks that have attached expectations from
userspace.

A new version of the proof-of-concept code to implement userspace
helpers from userspace is available at:

http://people.netfilter.org/pablo/userspace-conntrack-helpers/nf-ftp-helper-POC.tar.bz2

This patch also modifies the CT target to allow to set the
conntrack's userspace helper status flags. This flag is used
to tell the conntrack system to explicitly allocate the helper
extension.

This helper extension is useful to link the userspace expectations
with the master conntrack that is being tracked from one userspace
helper.

This feature fixes a problem in the current approach of the
userspace helper support. Basically, if the master conntrack that
has got a userspace expectation vanishes, the expectations point to
one invalid memory address. Thus, triggering an oops in the
expectation deletion event path.

I decided not to add a new revision of the CT target because
I only needed to add a new flag for it. I'll document in this
issue in the iptables manpage. I have also changed the return
value from EINVAL to EOPNOTSUPP if one flag not supported is
specified. Thus, in the future adding new features that only
require a new flag can be added without a new revision.

There is no official code using this in userspace (apart from
the proof-of-concept) that uses this infrastructure but there
will be some by beginning 2012.

Reported-by: Sam Roberts <vieuxtech@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: support individual atomic-get-and-reset of counters

This allows to use the get operation to atomically get-and-reset
counters.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: ctnetlink: use expect instead of master tuple in get operation

Use the expect tuple (if possible) instead of the master tuple for
the get operation. If two or more expectations come from the same
master, the returned expectation may not be the one that user-space
is requesting.

This is how it works for the expect deletion operation.

Although I think that nobody has been seriously using this. We
accept both possibilities, using the expect tuple if possible.
I decided to do it like this to avoid breaking backward
compatibility.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_conntrack: use atomic64 for accounting counters

We can use atomic64_t infrastructure to avoid taking a spinlock in fast
path, and remove inaccuracies while reading values in
ctnetlink_dump_counters() and connbytes_mt() on 32bit arches.

Suggested by Pablo.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_conntrack: make event callback registration per-netns

This patch fixes an oops that can be triggered following this recipe:

0) make sure nf_conntrack_netlink and nf_conntrack_ipv4 are loaded.
1) container is started.
2) connect to it via lxc-console.
3) generate some traffic with the container to create some conntrack
entries in its table.
4) stop the container: you hit one oops because the conntrack table
cleanup tries to report the destroy event to user-space but the
per-netns nfnetlink socket has already gone (as the nfnetlink
socket is per-netns but event callback registration is global).

To fix this situation, we make the ctnl_notifier per-netns so the
callback is registered/unregistered if the container is
created/destroyed.

Alex Bligh and Alexey Dobriyan originally proposed one small patch to
check if the nfnetlink socket is gone in nfnetlink_has_listeners,
but this is a very visited path for events, thus, it may reduce
performance and it looks a bit hackish to check for the nfnetlink
socket only to workaround this situation. As a result, I decided
to follow the bigger path choice, which seems to look nicer to me.

Cc: Alexey Dobriyan <adobriyan@gmail.com>
Reported-by: Alex Bligh <alex@alex.org.uk>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

rcu: convert uses of rcu_assign_pointer(x, NULL) to RCU_INIT_POINTER

When assigning a NULL value to an RCU protected pointer, no barrier
is needed. The rcu_assign_pointer, used to handle that but will soon
change to not handle the special case.

Convert all rcu_assign_pointer of NULL value.

//smpl
@@ expression P; @@

- rcu_assign_pointer(P, NULL)
+ RCU_INIT_POINTER(P, NULL)

// </smpl>

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rtnetlink: Compute and store minimum ifinfo dump size

The message size allocated for rtnl ifinfo dumps was limited to
a single page. This is not enough for additional interface info
available with devices that support SR-IOV and caused a bug in
which VF info would not be displayed if more than approximately
40 VFs were created per interface.

Implement a new function pointer for the rtnl_register service that will
calculate the amount of data required for the ifinfo dump and allocate
enough data to satisfy the request.

Signed-off-by: Greg Rose <gregory.v.rose@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

netfilter: ctnetlink: fix timestamp support for new conntracks

This patch fixes the missing initialization of the start time if
the timestamp support is enabled.

libnetfilter_conntrack/utils# conntrack -E &
libnetfilter_conntrack/utils# ./conntrack_create
tcp 6 109 ESTABLISHED src=1.1.1.1 dst=2.2.2.2 sport=1025 dport=21 packets=0 bytes=0 [UNREPLIED] src=2.2.2.2 dst=1.1.1.1 sport=21 dport=1025 packets=0 bytes=0 mark=0 delta-time=1303296401 use=2

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: ctnetlink: fix timestamp support for new conntracks

This patch fixes the missing initialization of the start time if
the timestamp support is enabled.

libnetfilter_conntrack/utils# conntrack -E &
libnetfilter_conntrack/utils# ./conntrack_create
tcp 6 109 ESTABLISHED src=1.1.1.1 dst=2.2.2.2 sport=1025 dport=21 packets=0 bytes=0 [UNREPLIED] src=2.2.2.2 dst=1.1.1.1 sport=21 dport=1025 packets=0 bytes=0 mark=0 delta-time=1303296401 use=2

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: ctnetlink: fix ctnetlink_parse_tuple() warning

net/netfilter/nf_conntrack_netlink.c: In function 'ctnetlink_parse_tuple':
net/netfilter/nf_conntrack_netlink.c:832:11: warning: comparison between 'enum ctattr_tuple' and 'enum ctattr_type'

Use ctattr_type for the 'type' parameter since that's the type of all attributes
passed to this function.

Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: ctnetlink: fix missing refcount increment during dumps

In 13ee6ac netfilter: fix race in conntrack between dump_table and
destroy, we recovered spinlocks to protect the dump of the conntrack
table according to reports from Stephen and acknowledgments on the
issue from Eric.

In that patch, the refcount bump that allows to keep a reference
to the current ct object was removed. However, we still decrement
the refcount for that object in the output path of
ctnetlink_dump_table():

if (last)
nf_ct_put(last)

Cc: Stephen Hemminger <stephen.hemminger@vyatta.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

Revert "netlink: test for all flags of the NLM_F_DUMP composite"

This reverts commit 0ab03c2b1478f2438d2c80204f7fef65b1bca9cf.

It breaks several things including the avahi daemon.

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

netfilter: nf_conntrack_tstamp: add flow-based timestamp extension

This patch adds flow-based timestamping for conntracks. This
conntrack extension is disabled by default. Basically, we use
two 64-bits variables to store the creation timestamp once the
conntrack has been confirmed and the other to store the deletion
time. This extension is disabled by default, to enable it, you
have to:

echo 1 > /proc/sys/net/netfilter/nf_conntrack_timestamp

This patch allows to save memory for user-space flow-based
loogers such as ulogd2. In short, ulogd2 does not need to
keep a hashtable with the conntrack in user-space to know
when they were created and destroyed, instead we use the
kernel timestamp. If we want to have a sane IPFIX implementation
in user-space, this nanosecs resolution timestamps are also
useful. Other custom user-space applications can benefit from
this via libnetfilter_conntrack.

This patch modifies the /proc output to display the delta time
in seconds since the flow start. You can also obtain the
flow-start date by means of the conntrack-tools.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: ctnetlink: fix loop in ctnetlink_get_conntrack()

This patch fixes a loop in ctnetlink_get_conntrack() that can be
triggered if you use the same socket to receive events and to
perform a GET operation. Under heavy load, netlink_unicast()
may return -EAGAIN, this error code is reserved in nfnetlink for
the module load-on-demand. Instead, we return -ENOBUFS which is
the appropriate error code that has to be propagated to
user-space.

Reported-by: Holger Eitzenberger <holger@eitzenberger.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: fix race in conntrack between dump_table and destroy

The netlink interface to dump the connection tracking table has a race
when entries are deleted at the same time. A customer reported a crash
and the backtrace showed thatctnetlink_dump_table was running while a
conntrack entry was being destroyed.
(see https://bugzilla.vyatta.com/show_bug.cgi?id=6402).

According to RCU documentation, when using hlist_nulls the reader
must handle the case of seeing a deleted entry and not proceed
further down the linked list. The old code would continue
which caused the scan to walk into the free list.

This patch uses locking (rather than RCU) for this operation which
is guaranteed safe, and no longer requires getting reference while
doing dump operation.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netlink: test for all flags of the NLM_F_DUMP composite

Due to NLM_F_DUMP is composed of two bits, NLM_F_ROOT | NLM_F_MATCH,
when doing "if (x & NLM_F_DUMP)", it tests for _either_ of the bits
being set. Because NLM_F_MATCH's value overlaps with NLM_F_EXCL,
non-dump requests with NLM_F_EXCL set are mistaken as dump requests.

Substitute the condition to test for _all_ bits being set.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

netfilter: fix export secctx error handling

In 1ae4de0cdf855305765592647025bde55e85e451, the secctx was exported
via the /proc/net/netfilter/nf_conntrack and ctnetlink interfaces
instead of the secmark.

That patch introduced the use of security_secid_to_secctx() which may
return a non-zero value on error.

In one of my setups, I have NF_CONNTRACK_SECMARK enabled but no
security modules. Thus, security_secid_to_secctx() returns a negative
value that results in the breakage of the /proc and `conntrack -L'
outputs. To fix this, we skip the inclusion of secctx if the
aforementioned function fails.

This patch also fixes the dynamic netlink message size calculation
if security_secid_to_secctx() returns an error, since its logic is
also wrong.

This problem exists in Linux kernel >= 2.6.37.

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

netfilter: nf_conntrack: don't always initialize ct->proto

ct->proto is big(60 bytes) due to structure ip_ct_tcp, and we don't need
to initialize the whole for all the other protocols. This patch moves
proto to the end of structure nf_conn, and pushes the initialization down
to the individual protocols.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

secmark: fix config problem when CONFIG_NF_CONNTRACK_SECMARK is not set

When CONFIG_NF_CONNTRACK_SECMARK is not set we accidentally attempt to use
the secmark fielf of struct nf_conn. Problem is when that config isn't set
the field doesn't exist. whoops. Wrap the incorrect usage in the config.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>

conntrack: export lsm context rather than internal secid via netlink

The conntrack code can export the internal secid to userspace. These are
dynamic, can change on lsm changes, and have no meaning in userspace. We
should instead be sending lsm contexts to userspace instead. This patch sends
the secctx (rather than secid) to userspace over the netlink socket. We use a
new field CTA_SECCTX and stop using the the old CTA_SECMARK field since it did
not send particularly useful information.

Signed-off-by: Eric Paris <eparis@redhat.com>
Reviewed-by: Paul Moore <paul.moore@hp.com>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: James Morris <jmorris@namei.org>

netfilter: ctnetlink: add expectation deletion events

This patch allows to listen to events that inform about
expectations destroyed.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: ctnetlink: add support for user-space expectation helpers

This patch adds the basic infrastructure to support user-space
expectation helpers via ctnetlink and the netfilter queuing
infrastructure NFQUEUE. Basically, this patch:

* adds NF_CT_EXPECT_USERSPACE flag to identify user-space
created expectations. I have also added a sanity check in
__nf_ct_expect_check() to avoid that kernel-space helpers
may create an expectation if the master conntrack has no
helper assigned.
* adds some branches to check if the master conntrack helper
exists, otherwise we skip the code that refers to kernel-space
helper such as the local expectation list and the expectation
policy.
* allows to set the timeout for user-space expectations with
no helper assigned.
* a list of expectations created from user-space that depends
on ctnetlink (if this module is removed, they are deleted).
* includes USERSPACE in the /proc output for expectations
that have been created by a user-space helper.

This patch also modifies ctnetlink to skip including the helper
name in the Netlink messages if no kernel-space helper is set
(since no user-space expectation has not kernel-space kernel
assigned).

You can access an example user-space FTP conntrack helper at:
http://people.netfilter.org/pablo/userspace-conntrack-helpers/nf-ftp-helper-userspace-POC.tar.bz

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: ctnetlink: allow to specify the expectation flags

With this patch, you can specify the expectation flags for user-space
created expectations.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: ctnetlink: missing validation of CTA_EXPECT_ZONE attribute

This patch adds the missing validation of the CTA_EXPECT_ZONE
attribute in the ctnetlink code.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: nf_conntrack: IPS_UNTRACKED bit

NOTRACK makes all cpus share a cache line on nf_conntrack_untracked
twice per packet. This is bad for performance.
__read_mostly annotation is also a bad choice.

This patch introduces IPS_UNTRACKED bit so that we can use later a
per_cpu untrack structure more easily.

A new helper, nf_ct_untracked_get() returns a pointer to
nf_conntrack_untracked.

Another one, nf_ct_untracked_status_or() is used by nf_nat_init() to add
IPS_NAT_DONE_MASK bits to untracked status.

nf_ct_is_untracked() prototype is changed to work on a nf_conn pointer.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: remove unnecessary returns from void function()s

This patch removes from net/ netfilter files
all the unnecessary return; statements that precede the
last closing brace of void functions.

It does not remove the returns that are immediately
preceded by a label as gcc doesn't like that.

Done via:
$ grep -rP --include=*.[ch] -l "return;\n}" net/ | \
xargs perl -i -e 'local $/ ; while (<>) { s/\n[ \t\n]+return;\n}/\n}/g; print; }'

Signed-off-by: Joe Perches <joe@perches.com>
[Patrick: changed to keep return statements in otherwise empty function bodies]
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: cleanup printk messages

Make sure all printk messages have a severity level.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: ctnetlink: compute message size properly

Message size should be dependent on the presence of an accounting
extension, not on CONFIG_NF_CT_ACCT definition.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.

2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).

* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

netfilter: ctnetlink: fix reliable event delivery if message building fails

This patch fixes a bug that allows to lose events when reliable
event delivery mode is used, ie. if NETLINK_BROADCAST_SEND_ERROR
and NETLINK_RECV_NO_ENOBUFS socket options are set.

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

netfilter: ctnetlink: fix creation of conntrack with helpers

This patch fixes a bug that triggers an assertion if you create
a conntrack entry with a helper and netfilter debugging is enabled.
Basically, we hit the assertion because the confirmation flag is
set before the conntrack extensions are added. To fix this, we
move the extension addition before the aforementioned flag is
set.

This patch also removes the possibility of setting a helper for
existing conntracks. This operation would also trigger the
assertion since we are not allowed to add new extensions for
existing conntracks. We know noone that could benefit from
this operation sanely.

Thanks to Eric Dumazet for initial posting a preliminary patch
to address this issue.

Reported-by: David Ramblewski <David.Ramblewski@atosorigin.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: ctnetlink: add zone support

Parse and dump the conntrack zone in ctnetlink.

Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: nf_conntrack: add support for "conntrack zones"

Normally, each connection needs a unique identity. Conntrack zones allow
to specify a numerical zone using the CT target, connections in different
zones can use the same identity.

Example:

iptables -t raw -A PREROUTING -i veth0 -j CT --zone 1
iptables -t raw -A OUTPUT -o veth1 -j CT --zone 1

Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: ctnetlink: dump expectation helper name

Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: ctnetlink: add missing netlink attribute policies

Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: nf_conntrack: fix hash resizing with namespaces

As noticed by Jon Masters <jonathan@jonmasters.org>, the conntrack hash
size is global and not per namespace, but modifiable at runtime through
/sys/module/nf_conntrack/hashsize. Changing the hash size will only
resize the hash in the current namespace however, so other namespaces
will use an invalid hash size. This can cause crashes when enlarging
the hashsize, or false negative lookups when shrinking it.

Move the hash size into the per-namespace data and only use the global
hash size to initialize the per-namespace value when instanciating a
new namespace. Additionally restrict hash resizing to init_net for
now as other namespaces are not handled currently.

Cc: stable@kernel.org
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

netfilter: nf_conntrack: fix hash resizing with namespaces

As noticed by Jon Masters <jonathan@jonmasters.org>, the conntrack hash
size is global and not per namespace, but modifiable at runtime through
/sys/module/nf_conntrack/hashsize. Changing the hash size will only
resize the hash in the current namespace however, so other namespaces
will use an invalid hash size. This can cause crashes when enlarging
the hashsize, or false negative lookups when shrinking it.

Move the hash size into the per-namespace data and only use the global
hash size to initialize the per-namespace value when instanciating a
new namespace. Additionally restrict hash resizing to init_net for
now as other namespaces are not handled currently.

Cc: stable@kernel.org
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: nf_conntrack: support conntrack templates

Support initializing selected parameters of new conntrack entries from a
"conntrack template", which is a specially marked conntrack entry attached
to the skb.

Currently the helper and the event delivery masks can be initialized this
way.

Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: ctnetlink: support selective event delivery

Add two masks for conntrack end expectation events to struct nf_conntrack_ecache
and use them to filter events. Their default value is "all events" when the
event sysctl is on and "no events" when it is off. A following patch will add
specific initializations. Expectation events depend on the ecache struct of
their master conntrack.

Signed-off-by: Patrick McHardy <kaber@trash.net>