linux-stable.git/net/netfilter, branch v5.4.296

netfilter: nft_socket: fix sk refcount leaks

2025-06-27T10:02:44+00:00

commit 8b26ff7af8c32cb4148b3e147c52f9e4c695209c upstream.

We must put 'sk' reference before returning.

Fixes: 039b1f4f24ec ("netfilter: nft_socket: fix erroneous socket assignment")
Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Greg Kroah-Hartman

netfilter: nf_tables: do not defer rule destruction via call_rcu

2025-06-04T12:32:36+00:00

commit b04df3da1b5c6f6dc7cdccc37941740c078c4043 upstream.

nf_tables_chain_destroy can sleep, it can't be used from call_rcu
callbacks.

Moreover, nf_tables_rule_release() is only safe for error unwinding,
while transaction mutex is held and the to-be-desroyed rule was not
exposed to either dataplane or dumps, as it deactives+frees without
the required synchronize_rcu() in-between.

nft_rule_expr_deactivate() callbacks will change ->use counters
of other chains/sets, see e.g. nft_lookup .deactivate callback, these
must be serialized via transaction mutex.

Also add a few lockdep asserts to make this more explicit.

Calling synchronize_rcu() isn't ideal, but fixing this without is hard
and way more intrusive. As-is, we can get:

WARNING: .. net/netfilter/nf_tables_api.c:5515 nft_set_destroy+0x..
Workqueue: events nf_tables_trans_destroy_work
RIP: 0010:nft_set_destroy+0x3fe/0x5c0
Call Trace:

nf_tables_trans_destroy_work+0x6b7/0xad0
process_one_work+0x64a/0xce0
worker_thread+0x613/0x10d0

In case the synchronize_rcu becomes an issue, we can explore alternatives.

One way would be to allocate nft_trans_rule objects + one nft_trans_chain
object, deactivate the rules + the chain and then defer the freeing to the
nft destroy workqueue. We'd still need to keep the synchronize_rcu path as
a fallback to handle -ENOMEM corner cases though.

Reported-by: syzbot+b26935466701e56cfdc2@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/67478d92.050a0220.253251.0062.GAE@google.com/T/
Fixes: c03d278fdf35 ("netfilter: nf_tables: wait for rcu grace period on net_device removal")
Signed-off-by: Florian Westphal
Signed-off-by: Pablo Neira Ayuso
Signed-off-by: Greg Kroah-Hartman

netfilter: nf_tables: wait for rcu grace period on net_device removal

2025-06-04T12:32:36+00:00

commit c03d278fdf35e73dd0ec543b9b556876b9d9a8dc upstream.

8c873e219970 ("netfilter: core: free hooks with call_rcu") removed
synchronize_net() call when unregistering basechain hook, however,
net_device removal event handler for the NFPROTO_NETDEV was not updated
to wait for RCU grace period.

Note that 835b803377f5 ("netfilter: nf_tables_netdev: unregister hooks
on net_device removal") does not remove basechain rules on device
removal, I was hinted to remove rules on net_device removal later, see
5ebe0b0eec9d ("netfilter: nf_tables: destroy basechain and rules on
netdevice removal").

Although NETDEV_UNREGISTER event is guaranteed to be handled after
synchronize_net() call, this path needs to wait for rcu grace period via
rcu callback to release basechain hooks if netns is alive because an
ongoing netlink dump could be in progress (sockets hold a reference on
the netns).

Note that nf_tables_pre_exit_net() unregisters and releases basechain
hooks but it is possible to see NETDEV_UNREGISTER at a later stage in
the netns exit path, eg. veth peer device in another netns:

 cleanup_net()
  default_device_exit_batch()
   unregister_netdevice_many_notify()
    notifier_call_chain()
     nf_tables_netdev_event()
      __nft_release_basechain()

In this particular case, same rule of thumb applies: if netns is alive,
then wait for rcu grace period because netlink dump in the other netns
could be in progress. Otherwise, if the other netns is going away then
no netlink dump can be in progress and basechain hooks can be released
inmediately.

While at it, turn WARN_ON() into WARN_ON_ONCE() for the basechain
validation, which should not ever happen.

Fixes: 835b803377f5 ("netfilter: nf_tables_netdev: unregister hooks on net_device removal")
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Greg Kroah-Hartman

netfilter: nf_tables: pass nft_chain to destroy function, not nft_ctx

2025-06-04T12:32:36+00:00

commit 8965d42bcf54d42cbc72fe34a9d0ec3f8527debd upstream.

It would be better to not store nft_ctx inside nft_trans object,
the netlink ctx strucutre is huge and most of its information is
never needed in places that use trans->ctx.

Avoid/reduce its usage if possible, no runtime behaviour change
intended.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Greg Kroah-Hartman

netfilter: conntrack: Bound nf_conntrack sysctl writes

2025-06-04T12:32:31+00:00

[ Upstream commit 8b6861390ffee6b8ed78b9395e3776c16fec6579 ]

nf_conntrack_max and nf_conntrack_expect_max sysctls were authorized to
be written any negative value, which would then be stored in the
unsigned int variables nf_conntrack_max and nf_ct_expect_max variables.

While the do_proc_dointvec_conv function is supposed to limit writing
handled by proc_dointvec proc_handler to INT_MAX. Such a negative value
being written in an unsigned int leads to a very high value, exceeding
this limit.

Moreover, the nf_conntrack_expect_max sysctl documentation specifies the
minimum value is 1.

The proc_handlers have thus been updated to proc_dointvec_minmax in
order to specify the following write bounds :

* Bound nf_conntrack_max sysctl writings between SYSCTL_ZERO
  and SYSCTL_INT_MAX.

* Bound nf_conntrack_expect_max sysctl writings between SYSCTL_ONE
  and SYSCTL_INT_MAX as defined in the sysctl documentation.

With this patch applied, sysctl writes outside the defined in the bound
will thus lead to a write error :

```
sysctl -w net.netfilter.nf_conntrack_expect_max=-1
sysctl: setting key "net.netfilter.nf_conntrack_expect_max": Invalid argument
```

Signed-off-by: Nicolas Bouchinet 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

netfilter: ipset: fix region locking in hash types

2025-06-04T12:32:26+00:00

[ Upstream commit 8478a729c0462273188263136880480729e9efca ]

Region locking introduced in v5.6-rc4 contained three macros to handle
the region locks: ahash_bucket_start(), ahash_bucket_end() which gave
back the start and end hash bucket values belonging to a given region
lock and ahash_region() which should give back the region lock belonging
to a given hash bucket. The latter was incorrect which can lead to a
race condition between the garbage collector and adding new elements
when a hash type of set is defined with timeouts.

Fixes: f66ee0410b1c ("netfilter: ipset: Fix "INFO: rcu detected stall in hash_xxx" reports")
Reported-by: Kota Toda 
Signed-off-by: Jozsef Kadlecsik 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

netfilter: nft_exthdr: fix offset with ipv4_find_option()

2025-04-10T12:29:35+00:00

[ Upstream commit 6edd78af9506bb182518da7f6feebd75655d9a0e ]

There is an incorrect calculation in the offset variable which causes
the nft_skb_copy_to_reg() function to always return -EFAULT. Adding the
start variable is redundant. In the __ip_options_compile() function the
correct offset is specified when finding the function. There is no need
to add the size of the iphdr structure to the offset.

Fixes: dbb5281a1f84 ("netfilter: nf_tables: add support for matching IPv4 options")
Signed-off-by: Alexey Kashavkin 
Reviewed-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

ipvs: prevent integer overflow in do_ip_vs_get_ctl()

2025-04-10T12:29:35+00:00

[ Upstream commit 80b78c39eb86e6b55f56363b709eb817527da5aa ]

The get->num_services variable is an unsigned int which is controlled by
the user.  The struct_size() function ensures that the size calculation
does not overflow an unsigned long, however, we are saving the result to
an int so the calculation can overflow.

Both "len" and "get->num_services" come from the user.  This check is
just a sanity check to help the user and ensure they are using the API
correctly.  An integer overflow here is not a big deal.  This has no
security impact.

Save the result from struct_size() type size_t to fix this integer
overflow bug.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Dan Carpenter 
Acked-by: Julian Anastasov 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

netfilter: nf_conncount: Fully initialize struct nf_conncount_tuple in insert_tree()

2025-04-10T12:29:35+00:00

[ Upstream commit d653bfeb07ebb3499c403404c21ac58a16531607 ]

Since commit b36e4523d4d5 ("netfilter: nf_conncount: fix garbage
collection confirm race"), `cpu` and `jiffies32` were introduced to
the struct nf_conncount_tuple.

The commit made nf_conncount_add() initialize `conn->cpu` and
`conn->jiffies32` when allocating the struct.
In contrast, count_tree() was not changed to initialize them.

By commit 34848d5c896e ("netfilter: nf_conncount: Split insert and
traversal"), count_tree() was split and the relevant allocation
code now resides in insert_tree().
Initialize `conn->cpu` and `conn->jiffies32` in insert_tree().

BUG: KMSAN: uninit-value in find_or_evict net/netfilter/nf_conncount.c:117 [inline]
BUG: KMSAN: uninit-value in __nf_conncount_add+0xd9c/0x2850 net/netfilter/nf_conncount.c:143
 find_or_evict net/netfilter/nf_conncount.c:117 [inline]
 __nf_conncount_add+0xd9c/0x2850 net/netfilter/nf_conncount.c:143
 count_tree net/netfilter/nf_conncount.c:438 [inline]
 nf_conncount_count+0x82f/0x1e80 net/netfilter/nf_conncount.c:521
 connlimit_mt+0x7f6/0xbd0 net/netfilter/xt_connlimit.c:72
 __nft_match_eval net/netfilter/nft_compat.c:403 [inline]
 nft_match_eval+0x1a5/0x300 net/netfilter/nft_compat.c:433
 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline]
 nft_do_chain+0x426/0x2290 net/netfilter/nf_tables_core.c:288
 nft_do_chain_ipv4+0x1a5/0x230 net/netfilter/nft_chain_filter.c:23
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_slow+0xf4/0x400 net/netfilter/core.c:626
 nf_hook_slow_list+0x24d/0x860 net/netfilter/core.c:663
 NF_HOOK_LIST include/linux/netfilter.h:350 [inline]
 ip_sublist_rcv+0x17b7/0x17f0 net/ipv4/ip_input.c:633
 ip_list_rcv+0x9ef/0xa40 net/ipv4/ip_input.c:669
 __netif_receive_skb_list_ptype net/core/dev.c:5936 [inline]
 __netif_receive_skb_list_core+0x15c5/0x1670 net/core/dev.c:5983
 __netif_receive_skb_list net/core/dev.c:6035 [inline]
 netif_receive_skb_list_internal+0x1085/0x1700 net/core/dev.c:6126
 netif_receive_skb_list+0x5a/0x460 net/core/dev.c:6178
 xdp_recv_frames net/bpf/test_run.c:280 [inline]
 xdp_test_run_batch net/bpf/test_run.c:361 [inline]
 bpf_test_run_xdp_live+0x2e86/0x3480 net/bpf/test_run.c:390
 bpf_prog_test_run_xdp+0xf1d/0x1ae0 net/bpf/test_run.c:1316
 bpf_prog_test_run+0x5e5/0xa30 kernel/bpf/syscall.c:4407
 __sys_bpf+0x6aa/0xd90 kernel/bpf/syscall.c:5813
 __do_sys_bpf kernel/bpf/syscall.c:5902 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5900 [inline]
 __ia32_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5900
 ia32_sys_call+0x394d/0x4180 arch/x86/include/generated/asm/syscalls_32.h:358
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0xb0/0x110 arch/x86/entry/common.c:387
 do_fast_syscall_32+0x38/0x80 arch/x86/entry/common.c:412
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:450
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4121 [inline]
 slab_alloc_node mm/slub.c:4164 [inline]
 kmem_cache_alloc_noprof+0x915/0xe10 mm/slub.c:4171
 insert_tree net/netfilter/nf_conncount.c:372 [inline]
 count_tree net/netfilter/nf_conncount.c:450 [inline]
 nf_conncount_count+0x1415/0x1e80 net/netfilter/nf_conncount.c:521
 connlimit_mt+0x7f6/0xbd0 net/netfilter/xt_connlimit.c:72
 __nft_match_eval net/netfilter/nft_compat.c:403 [inline]
 nft_match_eval+0x1a5/0x300 net/netfilter/nft_compat.c:433
 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline]
 nft_do_chain+0x426/0x2290 net/netfilter/nf_tables_core.c:288
 nft_do_chain_ipv4+0x1a5/0x230 net/netfilter/nft_chain_filter.c:23
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_slow+0xf4/0x400 net/netfilter/core.c:626
 nf_hook_slow_list+0x24d/0x860 net/netfilter/core.c:663
 NF_HOOK_LIST include/linux/netfilter.h:350 [inline]
 ip_sublist_rcv+0x17b7/0x17f0 net/ipv4/ip_input.c:633
 ip_list_rcv+0x9ef/0xa40 net/ipv4/ip_input.c:669
 __netif_receive_skb_list_ptype net/core/dev.c:5936 [inline]
 __netif_receive_skb_list_core+0x15c5/0x1670 net/core/dev.c:5983
 __netif_receive_skb_list net/core/dev.c:6035 [inline]
 netif_receive_skb_list_internal+0x1085/0x1700 net/core/dev.c:6126
 netif_receive_skb_list+0x5a/0x460 net/core/dev.c:6178
 xdp_recv_frames net/bpf/test_run.c:280 [inline]
 xdp_test_run_batch net/bpf/test_run.c:361 [inline]
 bpf_test_run_xdp_live+0x2e86/0x3480 net/bpf/test_run.c:390
 bpf_prog_test_run_xdp+0xf1d/0x1ae0 net/bpf/test_run.c:1316
 bpf_prog_test_run+0x5e5/0xa30 kernel/bpf/syscall.c:4407
 __sys_bpf+0x6aa/0xd90 kernel/bpf/syscall.c:5813
 __do_sys_bpf kernel/bpf/syscall.c:5902 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5900 [inline]
 __ia32_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5900
 ia32_sys_call+0x394d/0x4180 arch/x86/include/generated/asm/syscalls_32.h:358
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0xb0/0x110 arch/x86/entry/common.c:387
 do_fast_syscall_32+0x38/0x80 arch/x86/entry/common.c:412
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:450
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Reported-by: syzbot+83fed965338b573115f7@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=83fed965338b573115f7
Fixes: b36e4523d4d5 ("netfilter: nf_conncount: fix garbage collection confirm race")
Signed-off-by: Kohei Enju 
Reviewed-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

netfilter: Replace zero-length array with flexible-array member

2025-01-09T12:23:35+00:00

[ Upstream commit 6daf14140129d30207ed6a0a69851fa6a3636bda ]

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

Lastly, fix checkpatch.pl warning
WARNING: __aligned(size) is preferred over __attribute__((aligned(size)))
in net/bridge/netfilter/ebtables.c

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva 
Signed-off-by: Pablo Neira Ayuso 
Stable-dep-of: 542ed8145e6f ("netfilter: nft_set_hash: unaligned atomic read on struct nft_set_ext")
Signed-off-by: Sasha Levin