linux-stable.git/include/net, branch linux-6.1.y

netfilter: nft_ct: fix use-after-free in timeout object destroy

2026-04-18T08:35:57+00:00

commit f8dca15a1b190787bbd03285304b569631160eda upstream.

nft_ct_timeout_obj_destroy() frees the timeout object with kfree()
immediately after nf_ct_untimeout(), without waiting for an RCU grace
period. Concurrent packet processing on other CPUs may still hold
RCU-protected references to the timeout object obtained via
rcu_dereference() in nf_ct_timeout_data().

Add an rcu_head to struct nf_ct_timeout and use kfree_rcu() to defer
freeing until after an RCU grace period, matching the approach already
used in nfnetlink_cttimeout.c.

KASAN report:
 BUG: KASAN: slab-use-after-free in nf_conntrack_tcp_packet+0x1381/0x29d0
 Read of size 4 at addr ffff8881035fe19c by task exploit/80

 Call Trace:
  nf_conntrack_tcp_packet+0x1381/0x29d0
  nf_conntrack_in+0x612/0x8b0
  nf_hook_slow+0x70/0x100
  __ip_local_out+0x1b2/0x210
  tcp_sendmsg_locked+0x722/0x1580
  __sys_sendto+0x2d8/0x320

 Allocated by task 75:
  nft_ct_timeout_obj_init+0xf6/0x290
  nft_obj_init+0x107/0x1b0
  nf_tables_newobj+0x680/0x9c0
  nfnetlink_rcv_batch+0xc29/0xe00

 Freed by task 26:
  nft_obj_destroy+0x3f/0xa0
  nf_tables_trans_destroy_work+0x51c/0x5c0
  process_one_work+0x2c4/0x5a0

Fixes: 7e0b2b57f01d ("netfilter: nft_ct: add ct timeout support")
Cc: stable@vger.kernel.org
Signed-off-by: Tuan Do 
Signed-off-by: Florian Westphal 
Signed-off-by: Greg Kroah-Hartman

netfilter: nf_conntrack_expect: store netns and zone in expectation

2026-04-11T12:16:22+00:00

[ Upstream commit 02a3231b6d82efe750da6554ebf280e4a6f78756 ]

__nf_ct_expect_find() and nf_ct_expect_find_get() are called under
rcu_read_lock() but they dereference the master conntrack via
exp->master.

Since the expectation does not hold a reference on the master conntrack,
this could be dying conntrack or different recycled conntrack than the
real master due to SLAB_TYPESAFE_RCU.

Store the netns, the master_tuple and the zone in struct
nf_conntrack_expect as a safety measure.

This patch is required by the follow up fix not to dump expectations
that do not belong to this netns.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso 
Stable-dep-of: 917b61fa2042 ("netfilter: ctnetlink: ignore explicit helper on new expectations")
Signed-off-by: Sasha Levin

netfilter: nf_conntrack_expect: honor expectation helper field

2026-04-11T12:16:22+00:00

[ Upstream commit 9c42bc9db90a154bc61ae337a070465f3393485a ]

The expectation helper field is mostly unused. As a result, the
netfilter codebase relies on accessing the helper through exp->master.

Always set on the expectation helper field so it can be used to reach
the helper.

nf_ct_expect_init() is called from packet path where the skb owns
the ct object, therefore accessing exp->master for the newly created
expectation is safe. This saves a lot of updates in all callsites
to pass the ct object as parameter to nf_ct_expect_init().

This is a preparation patches for follow up fixes.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso 
Stable-dep-of: 917b61fa2042 ("netfilter: ctnetlink: ignore explicit helper on new expectations")
Signed-off-by: Sasha Levin

netfilter: Reorder fields in 'struct nf_conntrack_expect'

2026-04-11T12:16:22+00:00

[ Upstream commit 61e03e912da8212c3de2529054502e8388dfd484 ]

Group some variables based on their sizes to reduce holes.
On x86_64, this shrinks the size of 'struct nf_conntrack_expect' from 264
to 256 bytes.

This structure deserve a dedicated cache, so reducing its size looks nice.

Signed-off-by: Christophe JAILLET 
Reviewed-by: Simon Horman 
Signed-off-by: Florian Westphal 
Stable-dep-of: 917b61fa2042 ("netfilter: ctnetlink: ignore explicit helper on new expectations")
Signed-off-by: Sasha Levin

netlink: allow be16 and be32 types in all uint policy checks

2026-04-11T12:16:09+00:00

[ Upstream commit 5fac9b7c16c50c6c7699517f582b56e3743f453a ]

__NLA_IS_BEINT_TYPE(tp) isn't useful.  NLA_BE16/32 are identical to
NLA_U16/32, the only difference is that it tells the netlink validation
functions that byteorder conversion might be needed before comparing
the value to the policy min/max ones.

After this change all policy macros that can be used with UINT types,
such as NLA_POLICY_MASK() can also be used with NLA_BE16/32.

This will be used to validate nf_tables flag attributes which
are in bigendian byte order.

Signed-off-by: Florian Westphal 
Stable-dep-of: 8f15b5071b45 ("netfilter: ctnetlink: use netlink policy range checks")
Signed-off-by: Sasha Levin

udp: Fix wildcard bind conflict check when using hash2

2026-04-11T12:16:08+00:00

[ Upstream commit e537dd15d0d4ad989d56a1021290f0c674dd8b28 ]

When binding a udp_sock to a local address and port, UDP uses
two hashes (udptable->hash and udptable->hash2) for collision
detection. The current code switches to "hash2" when
hslot->count > 10.

"hash2" is keyed by local address and local port.
"hash" is keyed by local port only.

The issue can be shown in the following bind sequence (pseudo code):

bind(fd1,  "[fd00::1]:8888")
bind(fd2,  "[fd00::2]:8888")
bind(fd3,  "[fd00::3]:8888")
bind(fd4,  "[fd00::4]:8888")
bind(fd5,  "[fd00::5]:8888")
bind(fd6,  "[fd00::6]:8888")
bind(fd7,  "[fd00::7]:8888")
bind(fd8,  "[fd00::8]:8888")
bind(fd9,  "[fd00::9]:8888")
bind(fd10, "[fd00::10]:8888")

/* Correctly return -EADDRINUSE because "hash" is used
 * instead of "hash2". udp_lib_lport_inuse() detects the
 * conflict.
 */
bind(fail_fd, "[::]:8888")

/* After one more socket is bound to "[fd00::11]:8888",
 * hslot->count exceeds 10 and "hash2" is used instead.
 */
bind(fd11, "[fd00::11]:8888")
bind(fail_fd, "[::]:8888")      /* succeeds unexpectedly */

The same issue applies to the IPv4 wildcard address "0.0.0.0"
and the IPv4-mapped wildcard address "::ffff:0.0.0.0". For
example, if there are existing sockets bound to
"192.168.1.[1-11]:8888", then binding "0.0.0.0:8888" or
"[::ffff:0.0.0.0]:8888" can also miss the conflict when
hslot->count > 10.

TCP inet_csk_get_port() already has the correct check in
inet_use_bhash2_on_bind(). Rename it to
inet_use_hash2_on_bind() and move it to inet_hashtables.h
so udp.c can reuse it in this fix.

Fixes: 30fff9231fad ("udp: bind() optimisation")
Reported-by: Andrew Onyshchuk 
Signed-off-by: Martin KaFai Lau 
Reviewed-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20260319181817.1901357-1-martin.lau@linux.dev
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

rtnetlink: Honour NLM_F_ECHO flag in rtnl_delete_link

2026-04-11T12:16:07+00:00

[ Upstream commit f3a63cce1b4fbde7738395c5a2dea83f05de3407 ]

This patch use the new helper unregister_netdevice_many_notify() for
rtnl_delete_link(), so that the kernel could reply unicast when userspace
 set NLM_F_ECHO flag to request the new created interface info.

At the same time, the parameters of rtnl_delete_link() need to be updated
since we need nlmsghdr and portid info.

Suggested-by: Guillaume Nault 
Signed-off-by: Hangbin Liu 
Reviewed-by: Guillaume Nault 
Signed-off-by: Jakub Kicinski 
Stable-dep-of: 6931d21f87bc ("openvswitch: defer tunnel netdev_put to RCU release")
Signed-off-by: Sasha Levin

rtnetlink: pass netlink message header and portid to rtnl_configure_link()

2026-04-11T12:16:06+00:00

[ Upstream commit 1d997f1013079c05b642c739901e3584a3ae558d ]

This patch pass netlink message header and portid to rtnl_configure_link()
All the functions in this call chain need to add the parameters so we can
use them in the last call rtnl_notify(), and notify the userspace about
the new link info if NLM_F_ECHO flag is set.

- rtnl_configure_link()
  - __dev_notify_flags()
    - rtmsg_ifinfo()
      - rtmsg_ifinfo_event()
        - rtmsg_ifinfo_build_skb()
        - rtmsg_ifinfo_send()
	  - rtnl_notify()

Also move __dev_notify_flags() declaration to net/core/dev.h, as Jakub
suggested.

Signed-off-by: Hangbin Liu 
Reviewed-by: Guillaume Nault 
Signed-off-by: Jakub Kicinski 
Stable-dep-of: 6931d21f87bc ("openvswitch: defer tunnel netdev_put to RCU release")
Signed-off-by: Sasha Levin

netfilter: nft_set_pipapo: split gc into unlink and reclaim phase

2026-03-25T10:03:23+00:00

commit 9df95785d3d8302f7c066050117b04cd3c2048c2 upstream.

Yiming Qian reports Use-after-free in the pipapo set type:
  Under a large number of expired elements, commit-time GC can run for a very
  long time in a non-preemptible context, triggering soft lockup warnings and
  RCU stall reports (local denial of service).

We must split GC in an unlink and a reclaim phase.

We cannot queue elements for freeing until pointers have been swapped.
Expired elements are still exposed to both the packet path and userspace
dumpers via the live copy of the data structure.

call_rcu() does not protect us: dump operations or element lookups starting
after call_rcu has fired can still observe the free'd element, unless the
commit phase has made enough progress to swap the clone and live pointers
before any new reader has picked up the old version.

This a similar approach as done recently for the rbtree backend in commit
35f83a75529a ("netfilter: nft_set_rbtree: don't gc elements on insert").

Fixes: 3c4287f62044 ("nf_tables: Add set type for arbitrary concatenation of ranges")
Reported-by: Yiming Qian 
Signed-off-by: Florian Westphal 
Signed-off-by: Greg Kroah-Hartman

netfilter: nf_tables: de-constify set commit ops function argument

2026-03-25T10:03:23+00:00

commit 256001672153af5786c6ca148114693d7d76d836 upstream.

The set backend using this already has to work around this via ugly
cast, don't spread this pattern.

Signed-off-by: Florian Westphal 
Signed-off-by: Greg Kroah-Hartman