linux-stable.git/net, branch v6.18.46

net/sched: cls_bpf: reject dev-bound programs bound to a different device

2026-08-23T12:27:09+00:00

[ Upstream commit 120977e2c096deea4e866e4273be9220b957c29e ]

cls_bpf_prog_from_efd() obtained a SCHED_CLS program via
bpf_prog_get_type_dev() but never verified that a device-bound (offloaded)
program's bound netdev matches the TC netdev the classifier is being
attached to. This let a program loaded with prog_ifindex for device A be
attached via cls_bpf + skip_sw to device B; deleting device A then
destroyed the program's offload state while it was still attached to
device B, triggering a netdevsim WARN (panic with panic_on_warn=1).

Mirror the XDP attach path (net/core/dev.c) and reject the attach with
-EINVAL when a dev-bound program's bound device does not match the
target device.

Fixes: 2b3486bc2d23 ("bpf: Introduce device-bound XDP programs")
Reported-by: vega@nebusec.ai
Tested-by: Victor Nogueira 
Signed-off-by: Jamal Hadi Salim 
Acked-by: Daniel Borkmann 
Link: https://patch.msgid.link/20260809094418.901607-1-jhs@mojatatu.com
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

net/sched: cls_u32: skip hash tables in u32_bind_class()

2026-08-23T12:27:08+00:00

[ Upstream commit 6d3724e616faf952c3adcf8414fc21a828ef3709 ]

u32_walk() enumerates both struct tc_u_hnode and struct tc_u_knode
through the walker callback. u32_bind_class() unconditionally casts the
passed fh to tc_u_knode and accesses &n->res, so when fh is actually a
tc_u_hnode, which has no tcf_result member, this results in a
slab-out-of-bounds read of res->classid in tc_cls_bind_class().

The issue can be reproduced with the following commands:

    tc qdisc add dev lo root handle 1: hfsc
    tc class add dev lo parent 1: classid 1:1 hfsc sc rate 1000kbit
    tc filter add dev lo parent 1:1 protocol ip prio 1 u32 match u32 0 0 flowid 1:1
    tc class add dev lo parent 1: classid 1:2 hfsc sc rate 2000kbit

Fix this by skipping hash tables via the TC_U32_KEY(handle) check.

Fixes: 07d79fc7d94e ("net_sched: add reverse binding for tc class")
Signed-off-by: Zhang Changzhong 
Acked-by: Jamal Hadi Salim 
Link: https://patch.msgid.link/1786089038-36366-1-git-send-email-zhangchangzhong@huawei.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

net/sched: act_api: fix TOCTOU NULL deref on a->goto_chain

2026-08-23T12:27:08+00:00

[ Upstream commit f60b396ee174206fe08ebf997d16cd3801b77b22 ]

tcf_action_exec() handles TC_ACT_GOTO_CHAIN by first checking
rcu_access_pointer(a->goto_chain) and then calling
tcf_action_goto_chain_exec(), which does a second, independent
rcu_dereference_bh(a->goto_chain) read and immediately dereferences
chain->filter_chain. A concurrent tcf_action_set_ctrlact() (e.g. the gact
replace path) can clear a->goto_chain between the two reads, so the second
read returns NULL and tcf_action_goto_chain_exec() dereferences NULL.

Fix the race by doing a single rcu_dereference_bh() read of a->goto_chain
in tcf_action_exec(), checking it once for NULL, and passing the resulting
chain pointer into tcf_action_goto_chain_exec(). This turns the split
check/use into a single check/use on one value.

Fixes: ee3bbfe806cd ("net/sched: let actions use RCU to access 'goto_chain'")
Reported-by: vega@nebusec.ai
Tested-by: Victor Nogueira 
Signed-off-by: Jamal Hadi Salim 
Reviewed-by: Davide Caratti 
Link: https://patch.msgid.link/20260809090928.868186-1-jhs@mojatatu.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

af_packet: Don't send zero-byte data in tpacket_snd().

2026-08-23T12:27:08+00:00

[ Upstream commit 6bcd76c134c55c697148acb5c0194e9666abdf84 ]

syzbot reported a WARNING in __dev_queue_xmit() triggered via tpacket_snd():

skb_assert_len
WARNING: at include/linux/skbuff.h:2753 skb_assert_len
WARNING: at __dev_queue_xmit+0x21bc/0x4970 net/core/dev.c:4781

Call Trace:
 
 dev_queue_xmit include/linux/netdevice.h:3448 [inline]
 packet_xmit+0x243/0x310 net/packet/af_packet.c:276
 tpacket_snd net/packet/af_packet.c:2907 [inline]
 packet_sendmsg+0x28d6/0x4eb0 net/packet/af_packet.c:3134

When sending 0-byte packets via TPACKET ring buffer on devices with no
hard header (e.g. dev->hard_header_len == 0), tpacket_fill_skb()
populates an skb with skb->len == 0 and returns 0. tpacket_snd() then
forwards this empty skb to packet_xmit(), causing __dev_queue_xmit() to
hit skb_assert_len(skb).

Similar checks exist in packet_snd() via commit dc633700f00f
("net/af_packet: check len when min_header_len equals to 0") and in
packet_sendmsg_spkt() via commit 6a341729fb31 ("af_packet: Don't send
zero-byte data in packet_sendmsg_spkt().").

Return -EINVAL in tpacket_fill_skb() when skb->len is zero to reject
zero-length packets in tpacket_snd().

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot+30b93b6845b19cc38581@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/6a79e807.01d0871a.3a0d52.00ac.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet 
Reviewed-by: Willem de Bruijn 
Reviewed-by: Jiayuan Chen 
Link: https://patch.msgid.link/20260810150447.1220864-1-edumazet@google.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

net/tls: Fail tls_sw_splice_read() after a failed async decrypt

2026-08-23T12:27:08+00:00

[ Upstream commit 976df67f463db1fddaf2a32fb04f57ad2891a23d ]

When an async decrypt fails, tls_decrypt_done() records the error in
ctx->async_wait.err and calls tls_err_abort(), which stores it in
sk_err. tls_sw_recvmsg() and tls_sw_read_sock() each read
async_wait.err once they hold the reader lock and fail the call: a
record that did not authenticate breaks the connection.

tls_sw_splice_read() has no such check, and sk_err does not stand in
for one. tls_rx_rec_wait() tests sk_err only inside the loop it
skips whenever a record is already parsed, and the first reader to
reach sock_error() clears it, while async_wait.err persists. A
splice therefore keeps delivering records on a connection that
recvmsg() and read_sock() refuse to read.

Read async_wait.err in tls_sw_splice_read() as the other two readers
do.

Fixes: f314bfee81b1 ("tls: rx: return the already-copied data on crypto error")
Reviewed-by: Jakub Kicinski 
Signed-off-by: Chuck Lever 
Reviewed-by: Sabrina Dubroca 
Link: https://patch.msgid.link/20260806-tls-splice-crypto-fix-v1-1-a2624005a286@kernel.org
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

net: packet: fix wrong transport_header when sending VLAN-tagged frame

2026-08-23T12:27:08+00:00

[ Upstream commit 01fdecc0480d916c799dbee584833a4a37e94d06 ]

In packet_parse_headers(), when processing a VLAN-tagged frame,
skb_set_network_header() is called to advance network_header past the
VLAN tag to the inner protocol header. skb_probe_transport_header() is
then called with skb->protocol still set to the outer VLAN EtherType
(e.g. ETH_P_8021Q), while nhoff (derived from skb_network_offset())
already points past the VLAN tag to the inner protocol header.

In __skb_flow_dissect(), proto is initialized to ETH_P_8021Q and nhoff
points past the VLAN tag. When the dissector hits case ETH_P_8021Q, it
reads a struct vlan_hdr at nhoff via __skb_header_pointer(), but that
offset contains the inner protocol header (e.g. an IP header). The bytes
are misinterpreted as a VLAN header, yielding a garbage encapsulated
EtherType that matches no known protocol. The dissector returns false,
so skb_probe_transport_header() never calls skb_set_transport_header(),
leaving transport_header at its uninitialized sentinel value (~0U).

Move skb_probe_transport_header() to before skb_set_network_header(). At
the time skb_probe_transport_header() is called, network_header still
points to the VLAN header, so nhoff correctly points to the VLAN header.
The flow dissector can then parse the VLAN header, extract the inner
EtherType, and advance nhoff to the inner protocol header, allowing
transport_header to be set correctly.

Fixes: dfed913e8b55 ("net/af_packet: add VLAN support for AF_PACKET SOCK_RAW GSO")
Assisted-by: WChat:claude-opus-4-8
Signed-off-by: Wei Fang 
Reviewed-by: Willem de Bruijn 
Link: https://patch.msgid.link/20260807063405.688780-2-wei.fang@oss.nxp.com
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

tcp: fix icsk_ack.ato bitfield overflow

2026-08-23T12:27:08+00:00

[ Upstream commit 60837e4b840a9c3f7ec826e3584df0bc6542a2c2 ]

On cross-region connections we observed delayed ACKs suddenly turning
into immediate ACKs plus a TCP_MAX_QUICKACKS burst, as if the
connection had just received its first data segment.

Commit 95b9a87c6a6b ("tcp: record last received ipv6 flowlabel")
squeezed icsk_ack.ato into 8 bits, sized for TCP_DELACK_MAX. But both
writers still bound ato by icsk_rto, which can be well above 255
jiffies, so the bitfield assignment silently wraps mod 256: repeated
delack timer misses double ato up to icsk_rto, storing 320 as 64 and
256 as 0, and ato == 0 is the "first data packet" sentinel in
tcp_event_data_recv().

Clamp both writers to TCP_DELACK_MAX, which the static_assert already
guarantees to fit and tcp_send_delayed_ack() effectively caps ato at
anyway.

Fixes: 95b9a87c6a6b ("tcp: record last received ipv6 flowlabel")
Signed-off-by: Jiayuan Chen 
Reviewed-by: Neal Cardwell 
Link: https://patch.msgid.link/20260807014437.36687-1-jiayuan.chen@linux.dev
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

netfilter: ipset: let destroy callbacks adjust ext mem size

2026-08-23T12:27:07+00:00

[ Upstream commit 490937b88cb592cc0c5367758edd700fd5abd15c ]

For bitmap this change makes no difference, because destructors are
called synchronously.

List type however calls them via call_rcu() so accounting decrement can
happen after list_set_flush() set ext_size to 0.

'set->elements = 0' can be removed for the same reason in the list type
case, it calls 'set->elements--' for each element.

Fixes: 9e41f26a505c ("netfilter: ipset: Count non-static extension memory for userspace")
Suggested-by: Jozsef Kadlecsik 
Signed-off-by: Florian Westphal 
Acked-by: Jozsef Kadlecsik 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

netfilter: ipset: fix list type element drift bug

2026-08-23T12:27:07+00:00

[ Upstream commit 4cbd69766b35a089664cadb1f613bb85f7ef77a9 ]

If list_set_uadd() calls list_set_replace() to swap an expired entry,
the element count remains the same, therefore the increment must be elided.

Fixes: 702b71e7c666 ("netfilter: ipset: Add element count to all set types header")
Link: https://sashiko.dev/#/patchset/20260806101947.2802-1-fw%40strlen.de
Signed-off-by: Florian Westphal 
Acked-by: Jozsef Kadlecsik 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

netfilter: flowtable: publish GC-visible tuple last

2026-08-23T12:27:07+00:00

[ Upstream commit 2014ac62df9d45bb9a004a043e85df7be09ed780 ]

nf_flow_table_iterate() only treats original-direction tuple nodes as
owning entries. Publishing the original node first lets GC observe and
free a flow while flow_offload_add() is still inserting the reply node.
Publish the reply node first and the original node last so GC never
sees a partially installed flow.

KASAN can trigger slab-use-after-free read and write reports in the
flowtable/rhashtable path (rht_deferred_worker, jhash, flow_offload_del,
flow_offload_lookup, etc.).

Fixes: ac2a66665e23 ("netfilter: add generic flow table infrastructure")
Signed-off-by: Jérémy Jean 
Assisted-by: Codex:gpt-5
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin