linux-stable.git/include/net, branch v6.12.109

net: cap advertised IP tunnel headroom

2026-09-07T15:18:22+00:00

commit 6b222adeb9340306e2ff97127c76117abb9b3df8 upstream.

IP tunnel devices derive their advertised needed_headroom from lower
output devices. A stack of user-created devices can make the derived
value larger than the 16-bit skb header offsets can represent. Once IP
output reserves it, skb head expansion can wrap those offsets.

The runtime transmit path already caps a growing needed_headroom at 512.
Apply the same cap when tunnel configuration publishes needed_headroom
derived from a lower output device.

Capping the advertised value is safe: IP tunnel transmit still expands
the skb when a packet needs more headroom. A nonsensical stacked
configuration can therefore incur an extra reallocation, but it cannot
publish an unbounded reservation to upper layers.

Fixes: 1a37e412a022 ("net: Use 16bits for *_headers fields of struct skbuff")
Cc: stable@vger.kernel.org
Reported-by: Vega 
Signed-off-by: Zhiling Zou 
Reviewed-by: Ido Schimmel 
Link: https://patch.msgid.link/ba04a1fd6bfae2377607fad5d8f80f7eb80fd4c4.1786542637.git.zhilinz@nebusec.ai
Signed-off-by: Paolo Abeni 
Signed-off-by: Greg Kroah-Hartman

sctp: fix stream->outcnt underflow on duplicate RECONF responses

2026-09-07T15:18:16+00:00

commit 3faf13aff243ca9f78d08b1a2956ef5a6fc77b6e upstream.

A cached RECONF chunk may contain more than one request parameter.  A
duplicate response can therefore find and process the same ADD_OUT request
again while another parameter is still outstanding, rolling back outcnt
twice and possibly underflowing it.

Track outstanding request types as bits and clear each bit after its first
response.  Later responses for the same request are then ignored.

Fixes: 11ae76e67a17 ("sctp: implement receiver-side procedures for the Reconf Response Parameter")
Cc: stable@kernel.org
Reported-by: TencentOS Corvus AI 
Link: https://lore.kernel.org/netdev/20260730110225.37371-1-juny24602@gmail.com/
Suggested-by: Xin Long 
Assisted-by: tencentos-corvus-ai:kimi-k3
Signed-off-by: Jun Yang 
Link: https://patch.msgid.link/20260824081832.98717-3-juny24602@gmail.com
Signed-off-by: Paolo Abeni 
Signed-off-by: Greg Kroah-Hartman

inet: frags: change inet_frag_kill() to defer refcount updates

2026-08-27T12:32:04+00:00

[ Upstream commit eb0dfc0ef195a04e519b15d73cf25d8c25ee8df7 ]

In the following patch, we no longer assume inet_frag_kill()
callers own a reference.

Consuming two refcounts from inet_frag_kill() would lead in UAF.

Propagate the pointer to the refs that will be consumed later
by the final inet_frag_putn() call.

Signed-off-by: Eric Dumazet 
Link: https://patch.msgid.link/20250312082250.1803501-4-edumazet@google.com
Signed-off-by: Paolo Abeni 
Stable-dep-of: 653d7ddf6cba ("inet: frags: publish queues before arming timer")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

inet: frags: add inet_frag_putn() helper

2026-08-27T12:32:04+00:00

[ Upstream commit ae2d90355aa5592b0e99c8bbb4c3fa1d8e205f1b ]

inet_frag_putn() can release multiple references
in one step.

Use it in inet_frags_free_cb().

Replace inet_frag_put(X) with inet_frag_putn(X, 1)

Signed-off-by: Eric Dumazet 
Link: https://patch.msgid.link/20250312082250.1803501-2-edumazet@google.com
Signed-off-by: Paolo Abeni 
Stable-dep-of: 653d7ddf6cba ("inet: frags: publish queues before arming timer")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

ip_tunnel: adapt iptunnel_xmit_stats() to NETDEV_PCPU_STAT_DSTATS

2026-08-23T12:22:51+00:00

commit 8431c602f551549f082bbfa67f3003f2d8e3e132 upstream.

Blamed commits forgot that vxlan/geneve use udp_tunnel[6]_xmit_skb() which
call iptunnel_xmit_stats().

iptunnel_xmit_stats() was assuming tunnels were only using
NETDEV_PCPU_STAT_TSTATS.

@syncp offset in pcpu_sw_netstats and pcpu_dstats is different.

32bit kernels would either have corruptions or freezes if the syncp
sequence was overwritten.

This patch also moves pcpu_stat_type closer to dev->{t,d}stats to avoid
a potential cache line miss since iptunnel_xmit_stats() needs to read it.

Fixes: 6fa6de302246 ("geneve: Handle stats using NETDEV_PCPU_STAT_DSTATS.")
Fixes: be226352e8dc ("vxlan: Handle stats using NETDEV_PCPU_STAT_DSTATS.")
Signed-off-by: Eric Dumazet 
Reviewed-by: Guillaume Nault 
Link: https://patch.msgid.link/20260311123110.1471930-1-edumazet@google.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

tcp: challenge ACK for non-exact RST in SYN-RECEIVED

2026-08-23T12:22:45+00:00

[ Upstream commit a28c4fcbf774e23b4779cae468e3497a5ad1f4a1 ]

The SYN-RECEIVED request-socket path in tcp_check_req() accepts an
in-window RST without requiring SEG.SEQ to exactly match RCV.NXT.  A
non-exact RST therefore removes the request instead of eliciting a
challenge ACK.

RFC 9293 section 3.10.7.4 applies the RFC 5961 reset check in
SYN-RECEIVED: an exact RST resets the connection, while a non-exact
in-window RST must trigger a challenge ACK and be dropped.

Apply that check before the ACK-field validation, following the RFC
sequence-number, RST, then ACK processing order.  Factor the per-netns
challenge ACK quota out of tcp_send_challenge_ack() so request sockets
can share it.  Use the request socket's send_ack() callback and its own
out-of-window ACK timestamp to send and rate-limit the response.

Reported-by: Yuxiang Yang 
Reported-by: Yizhou Zhao 
Reported-by: Ao Wang 
Reported-by: Xuewei Feng 
Reported-by: Qi Li 
Reported-by: Ke Xu 
Fixes: 282f23c6ee34 ("tcp: implement RFC 5961 3.2")
Cc: stable@vger.kernel.org
Signed-off-by: Yuxiang Yang 
Reviewed-by: Eric Dumazet 
Link: https://patch.msgid.link/20260717081443.809393-2-yangyx22@mails.tsinghua.edu.cn
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

tcp: fast path functions later

2026-08-23T12:22:45+00:00

[ Upstream commit 61b2f7baa9779b12a7bf1b9800a3f2a2549a1315 ]

The following patch will use tcp_ecn_mode_accecn(),
TCP_ACCECN_CEP_INIT_OFFSET, TCP_ACCECN_CEP_ACE_MASK in
__tcp_fast_path_on() to make new flag for AccECN.

No functional changes.

Signed-off-by: Ilpo Järvinen 
Signed-off-by: Chia-Yu Chang 
Reviewed-by: Eric Dumazet 
Link: https://patch.msgid.link/20250911110642.87529-3-chia-yu.chang@nokia-bell-labs.com
Signed-off-by: Jakub Kicinski 
Stable-dep-of: a28c4fcbf774 ("tcp: challenge ACK for non-exact RST in SYN-RECEIVED")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

tcp: Pass flags to __tcp_send_ack

2026-08-23T12:22:45+00:00

[ Upstream commit 9866884ce8ef25338c5b33cbb97c2b5d92088528 ]

Accurate ECN needs to send custom flags to handle IP-ECN
field reflection during handshake.

Signed-off-by: Ilpo Järvinen 
Signed-off-by: Chia-Yu Chang 
Reviewed-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Stable-dep-of: a28c4fcbf774 ("tcp: challenge ACK for non-exact RST in SYN-RECEIVED")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

ipvs: separate destination availability state

2026-08-23T12:22:35+00:00

commit cdcc4e46180df8161f4d2f3c6fd6beaf6990133d upstream.

IPVS configuration paths update destination availability while connection
accounting updates destination overload state. The two independent states
share dest->flags, so their read-modify-write updates can race and lose one
another.

Keep OVERLOAD in flags, where the preceding patch serializes its updates
with dst_lock, and move AVAILABLE to cflags. This keeps configuration-
controlled availability out of the scheduler hot cacheline until a
scheduler needs to check it. It also prevents availability updates from
clobbering overload state.

The destination status bits are not exposed through the IPVS sockopt or
netlink interfaces, so keep their definitions in the internal IPVS header.

Readers can still observe stale destination state; this does not provide a
cross-field snapshot.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Reported-by: Yizhou Zhao 
Reported-by: Yuxiang Yang 
Reported-by: Ao Wang 
Reported-by: Xuewei Feng 
Reported-by: Qi Li 
Reported-by: Ke Xu 
Link: https://lore.kernel.org/all/8913381c-1e02-35c7-0ec4-61de5a12fd35@ssi.bg/
Assisted-by: Claude-Code:GLM-5.2
Suggested-by: Julian Anastasov 
Signed-off-by: Yizhou Zhao 
Acked-by: Julian Anastasov 
Signed-off-by: Pablo Neira Ayuso 
(cherry picked from commit cdcc4e46180df8161f4d2f3c6fd6beaf6990133d)
[ Julian: Backport by removing the hunks from ip_vs_xmit.c ]
Signed-off-by: Julian Anastasov 
Signed-off-by: Sasha Levin

net/sched: act_gact, act_police: range check the fallback control action

2026-08-19T16:14:27+00:00

commit 883b56ae58fe657d8497806c7059646e9ba6dbd0 upstream.

tcf_action_check_ctrlact() range checks the primary control action:

	if (!opcode)
		ret = action > TC_ACT_VALUE_MAX ? -EINVAL : 0;

TC_ACT_VALUE_MAX is TC_ACT_TRAP, so kernel-internal verdicts above it
cannot be set that way. But act_gact and act_police each carry a second,
independent control action supplied by user space that never reaches that
helper - TCA_GACT_PROB.paction and TCA_POLICE_RESULT. Both only reject
TC_ACT_GOTO_CHAIN, so any other value is stored verbatim and returned
verbatim from the action.

In particular user space can store TC_ACT_CONSUMED, which is
TC_ACT_VALUE_MAX + 1 and is deliberately not part of the UAPI value
range. That verdict tells every caller the action took ownership of the
skb, so nobody frees it: sch_handle_ingress(), sch_handle_egress() and
tcf_qevent_handle() all deliberately skip the free for it. The result is
one leaked sk_buff plus its data buffer per packet traversing the filter,
unbounded, for all traffic on the chain including kernel-generated
packets.

Both are trivially deterministic. act_gact clamps tcfg_pval to >= 1, so
with pval = 1 gact_determ() returns the fallback for every packet.
act_police has no mandatory rate, so rate = 0 leaves tcfp_mtu = ~0 and
tcf_police_mtu_check() always passes.

TC_ACT_CONSUMED was added by commit 720f22fed81b ("net: sched: refactor
reinsert action"), after both goto-chain guards were written:
commit 9469f375ab09 ("net/sched: act_gact: disallow 'goto chain' on
fallback control action") and
commit c08f5ed5d625 ("net/sched: act_police: disallow 'goto chain' on
fallback control action"). Neither guard was widened when the new
verdict appeared.

Factor the existing range test out of tcf_action_check_ctrlact() as
tcf_action_valid() and apply it to both fallbacks. The helper cannot call
tcf_action_check_ctrlact() directly because that also allocates a
goto_chain, which is exactly what these two sites must not do.

Reproduced on v7.2-rc6: kmemleak reports one leaked 232-byte
skbuff_head_cache object plus its 704-byte data buffer per packet. With
this patch both configurations are rejected with -EINVAL and kmemleak
reports none.

Fixes: 720f22fed81b ("net: sched: refactor reinsert action")
Cc: stable@vger.kernel.org # v5.3+
Signed-off-by: Hyunjung Ko 
Acked-by: Jamal Hadi Salim 
Tested-by: Victor Nogueira 
Link: https://patch.msgid.link/20260806101252.809593-1-hj351016@gmail.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman