Pablo Neira Ayuso says:
====================
Netfilter fixes for net
The following patchset contains Netfilter fixes for net:
1) Revalidate bridge ports, add missing NULL checks to fetch the bridge
device by the port. From Florian Westphal.
2) Fix netdevice refcount leak in the error path of nft_fwd hardware
offload function, also from Florian.
3) Unregister helper expectfn callback on conntrack helper module
removal, otherwise dangling pointer remains in place,
from Weiming Shi.
4) Fix possible pointer infoleak in getsockopt() IPT_SO_GET_ENTRIES,
From Kyle Zeng.
5) Validate that device MAC header is present before nf_syslog
accesses it. From Xiang Mei.
6-8) Three patches to address a possible infoleak of stale stack
data in three nf_tables expressions, due to mismatch in the
_init() and _eval() function which is possible since 14fb07130c.
From Davide Ornaghi and Florian Westphal.
netfilter pull request 26-06-10
* tag 'nf-26-06-10' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
netfilter: nft_meta_bridge: fix stale stack leak via IIFHWADDR register
netfilter: nft_fib: fix stale stack leak via the OIFNAME register
netfilter: nft_exthdr: fix register tracking for F_PRESENT flag
netfilter: nf_log: validate MAC header was set before dumping it
netfilter: x_tables: avoid leaking percpu counter pointers
netfilter: nf_conntrack: destroy stale expectfn expectations on unregister
netfilter: nf_tables_offload: drop device refcount on error
netfilter: revalidate bridge ports
====================
Link: https://patch.msgid.link/20260610161629.214092-1-pablo@netfilter.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Steffen Klassert says:
====================
pull request (net): ipsec 2026-06-10
1) xfrm: iptfs: preserve shared-frag marker in iptfs_consume_frags()
Propagate SKBFL_SHARED_FRAG when paged fragments are moved between
skbs so ESP can decide whether in-place crypto is safe.
2) xfrm: iptfs: fix use-after-free on first_skb in __input_process_payload
Replace the unlocked read of xtfs->ra_newskb with a local flag so a
concurrent reassembly can no longer free first_skb between
spin_unlock and the post-loop check.
3) xfrm: policy: fix use-after-free on inexact bin in xfrm_policy_bysel_ctx()
Prune the inexact bin under xfrm_policy_lock so a concurrent
xfrm_hash_rebuild() can no longer free it before xfrm_policy_kill()
dereferences it.
4) xfrm: iptfs: fix ABBA deadlock in iptfs_destroy_state()
Move hrtimer_cancel() for the output and drop timers ahead of their
spinlocks, breaking the softirq/lock cycle that could deadlock
against the timer callbacks on SMP.
5) xfrm: espintcp: do not reuse an in-progress partial send
Fail a new send when espintcp_push_msgs() returns with emsg->len
still set, so a blocking caller can no longer overwrite ctx->partial
while a previous transfer still owns it.
6) esp: fix page frag reference leak on skb_to_sgvec failure
Add a flag to esp_ssg_unref() to unconditionally unref the source
scatterlist, releasing the old page references that are otherwise
leaked when the second skb_to_sgvec() in esp_output_tail() fails.
Please pull or let me know if there are problems.
ipsec-2026-06-10
* tag 'ipsec-2026-06-10' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec:
esp: fix page frag reference leak on skb_to_sgvec failure
xfrm: espintcp: do not reuse an in-progress partial send
xfrm: iptfs: fix ABBA deadlock in iptfs_destroy_state()
xfrm: policy: fix use-after-free on inexact bin in xfrm_policy_bysel_ctx()
xfrm: iptfs: fix use-after-free on first_skb in __input_process_payload
xfrm: iptfs: preserve shared-frag marker in iptfs_consume_frags()
====================
Link: https://patch.msgid.link/20260610140800.2562818-1-steffen.klassert@secunet.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
For NFT_FIB_RESULT_OIFNAME the destination register is declared with
len = IFNAMSIZ (four 32-bit registers), but on the lookup-fail,
RTN_LOCAL and oif-mismatch paths nft_fib{4,6}_eval() only writes one
register via "*dest = 0". The remaining three registers are left as
whatever was on the stack in nft_do_chain()'s struct nft_regs, and a
downstream expression that loads the register span can leak that
uninitialised kernel stack to userspace.
The NFTA_FIB_F_PRESENT existence check has the same shape: it is only
meaningful for NFT_FIB_RESULT_OIF, yet it was accepted for any result type
while the eval stores a single byte via nft_reg_store8(), leaving the rest
of the declared span stale.
Fix both:
- replace the bare "*dest = 0" in the eval with nft_fib_store_result(),
which strscpy_pad()s the whole IFNAMSIZ for OIFNAME (and is already
used on the other early-return path), and
- restrict NFTA_FIB_F_PRESENT to NFT_FIB_RESULT_OIF and declare its
destination as a single u8, so the marked span matches the one byte
the eval writes.
Fixes: f6d0cbcf09 ("netfilter: nf_tables: add fib expression")
Suggested-by: Florian Westphal <fw@strlen.de>
Cc: stable@vger.kernel.org
Signed-off-by: Davide Ornaghi <d.ornaghi97@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The native and compat get-entries paths copy the fixed rule entry header
from the kernelized rule blob to userspace before overwriting the entry's
counter fields with a sanitized counter snapshot.
On SMP kernels, entry->counters.pcnt contains the percpu allocation
address used by x_tables rule counters. A caller can provide a userspace
buffer that faults during the initial fixed-header copy after pcnt has
been copied but before the later sanitized counter copy runs. The syscall
then returns -EFAULT while leaving the raw percpu pointer in userspace.
Copy only the fixed entry prefix before counters from the kernelized rule
blob, then copy the sanitized counter snapshot into the counter field.
Apply this ordering to the IPv4, IPv6, and ARP native and compat
get-entries implementations so a fault cannot expose the internal percpu
counter pointer.
Fixes: 71ae0dff02 ("netfilter: xtables: use percpu rule counters")
Signed-off-by: Kyle Zeng <kylebot@openai.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
NAT helpers such as nf_nat_h323 store a raw pointer to module text in
exp->expectfn (e.g. ip_nat_q931_expect). nf_ct_helper_expectfn_unregister()
only unlinks the callback descriptor and never walks the expectation table,
so an expectation pending at module removal survives with a dangling
exp->expectfn into freed module text.
When the expected connection arrives, init_conntrack() invokes
exp->expectfn(), now a stale pointer into the unloaded module. Reproduced
on a KASAN build by loading the H.323 helpers, creating a Q.931
expectation, unloading nf_nat_h323, then connecting to the expected port:
Oops: int3: 0000 [#1] SMP KASAN NOPTI
RIP: 0010:0xffffffffa06102d1
init_conntrack.isra.0 (net/netfilter/nf_conntrack_core.c:1862)
nf_conntrack_in (net/netfilter/nf_conntrack_core.c:2049)
ipv4_conntrack_local (net/netfilter/nf_conntrack_proto.c:223)
nf_hook_slow (net/netfilter/core.c:619)
__ip_local_out (net/ipv4/ip_output.c:120)
__tcp_transmit_skb (net/ipv4/tcp_output.c:1715)
tcp_connect (net/ipv4/tcp_output.c:4374)
tcp_v4_connect (net/ipv4/tcp_ipv4.c:345)
__sys_connect (net/socket.c:2167)
Modules linked in: nf_conntrack_h323 [last unloaded: nf_nat_h323]
Reaching the dangling state requires CAP_SYS_MODULE in the initial user
namespace to remove a NAT helper that still has live expectations, so this
is a robustness fix; leaving an expectation pointing at freed text is wrong
regardless.
Add nf_ct_helper_expectfn_destroy(), which walks the expectation table and
drops every expectation whose ->expectfn matches the descriptor being torn
down. Call it from each NAT helper's exit path after the existing RCU grace
period, so no expectation outlives the code it points at and no extra
synchronize_rcu() is introduced. With the fix, the same reproducer runs to
completion without the Oops.
Fixes: f587de0e2f ("[NETFILTER]: nf_conntrack/nf_nat: add H.323 helper port")
Reported-by: Xiang Mei <xmei5@asu.edu>
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Weiming Shi <bestswngs@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
In esp_output_tail(), when esp->inplace is false, the old skb page frags
are replaced with a new page from the xfrm page_frag cache The source
scatterlist (sg) is built from the old frags before the replacement, and
esp_ssg_unref() is responsible for releasing the old page references
after the crypto operation completes
However, if the second skb_to_sgvec() call (which builds the destination
scatterlist from the new page) fails, the code jumps to error_free which
only calls kfree(tmp). The old page frag references captured in the
source scatterlist are never released:
1 sg[] is built from old frags via skb_to_sgvec() (no extra get_page)
2 nr_frags is set to 1 and frag[0] is replaced with the new page
3 Second skb_to_sgvec() fails -> goto error_free
Fix this by adding a bool parameter to esp_ssg_unref() that, when true,
unconditionally unrefs the source scatterlist frags. Since req->src is
not yet initialized by aead_request_set_crypt() at the point of the
error, the source scatterlist is obtained directly via esp_req_sg()
Existing callers pass false to preserve the original behavior
The same issue exists in both esp4 and esp6 as the code is identical
Fixes: cac2661c53 ("esp4: Avoid skb_cow_data whenever possible")
Fixes: 03e2a30f6a ("esp6: Avoid skb_cow_data whenever possible")
Signed-off-by: Alessandro Schino <7991aleschino@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
On netns teardown, fqdir_pre_exit() walks the fqdir rhashtable and
flushes every fragment queue that is not yet complete using
inet_frag_queue_flush(). That helper frees all the skbs queued on the
fragment queue but does not set INET_FRAG_COMPLETE, and leaves
q->fragments_tail and q->last_run_head pointing at the freed skbs.
The queue itself stays in the rhashtable.
fqdir_pre_exit() first lowers high_thresh to 0 to stop new queue lookups,
but it cannot stop a fragment that already obtained the queue through
inet_frag_find() earlier and stalled just before taking the queue lock.
Once that fragment resumes after the flush and takes the queue lock,
it passes the INET_FRAG_COMPLETE check and then dereferences the freed
fragments_tail. inet_frag_queue_insert() reads FRAG_CB() and ->len of
that pointer and, on the append path, writes ->next_frag, causing a
slab use-after-free. IPv6, nf_conntrack_reasm6 and 6lowpan reassembly
share the same flush path and are affected as well.
Reset rb_fragments, fragments_tail and last_run_head in
inet_frag_queue_flush() so a flushed queue no longer points at the
freed skbs. A fragment that resumes after the flush and takes the
queue lock then finds an empty queue and starts a new run instead of
dereferencing the freed fragments_tail. ip_frag_reinit() already
performed this reset after its own flush, so drop the now duplicate
code there.
Cc: stable@vger.kernel.org
Fixes: 006a5035b4 ("inet: frags: flush pending skbs in fqdir_pre_exit()")
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com>
Link: https://patch.msgid.link/ah6ukYq5G98LshdA@v4bel
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
On the UDP receive path skb->dev is repurposed as dev_scratch (the
truesize/state cache set by udp_set_dev_scratch()), through the
union { struct net_device *dev; unsigned long dev_scratch; } in sk_buff.
When a UDP socket is in a sockmap, sk_data_ready is
sk_psock_verdict_data_ready(), which calls udp_read_skb() -> recv_actor()
(sk_psock_verdict_recv) to run the attached SK_SKB verdict program in softirq.
If that program calls a socket-lookup helper (bpf_sk_lookup_tcp/udp,
bpf_skc_lookup_tcp), bpf_skc_lookup() does:
if (skb->dev)
caller_net = dev_net(skb->dev);
skb->dev still holds the dev_scratch value (a non-NULL integer), so dev_net()
dereferences it as a struct net_device * and the kernel takes a general
protection fault on a non-canonical address in softirq:
Oops: general protection fault, probably for non-canonical address 0x1010000800004a0
CPU: 1 UID: 0 PID: 1406 Comm: syz.2.19 Not tainted 7.1.0-rc6 #1 PREEMPT(full)
RIP: 0010:bpf_skc_lookup net/core/filter.c:7033 [inline]
RIP: 0010:bpf_sk_lookup+0x45/0x160 net/core/filter.c:7047
Call Trace:
<IRQ>
bpf_prog_4675cb904b7071f8+0x12e/0x14e
bpf_prog_run_pin_on_cpu+0xc6/0x1f0
sk_psock_verdict_recv+0x1ba/0x350
udp_read_skb+0x31a/0x370
sk_psock_verdict_data_ready+0x2e3/0x600
__udp_enqueue_schedule_skb+0x4c8/0x650
udpv6_queue_rcv_one_skb+0x3ec/0x740
udp6_unicast_rcv_skb+0x11d/0x140
ip6_protocol_deliver_rcu+0x61e/0x950
ip6_input_finish+0xa9/0x150
NF_HOOK+0x286/0x2f0
ip6_input+0x117/0x220
NF_HOOK+0x286/0x2f0
__netif_receive_skb+0x85/0x200
process_backlog+0x374/0x9a0
__napi_poll+0x4f/0x1c0
net_rx_action+0x3b0/0x770
handle_softirqs+0x15a/0x460
do_softirq+0x57/0x80
</IRQ>
The rmem charge that dev_scratch accounted for is released by skb_recv_udp() on
dequeue, just above, so the scratch is dead by the time recv_actor() runs. Clear
skb->dev so bpf_skc_lookup() falls back to sock_net(skb->sk), which
skb_set_owner_sk_safe() set just above.
Fixes: 965b57b469 ("net: Introduce a new proto_ops ->read_skb()")
Cc: stable@vger.kernel.org
Signed-off-by: Sechang Lim <rhkrqnwk98@gmail.com>
Reviewed-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260603162737.697215-1-rhkrqnwk98@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This patch restricts setting Loose Source and Record Route (LSRR)
and Strict Source and Record Route (SSRR) IP options to users
with CAP_NET_RAW capability.
This prevents unprivileged applications from forcing packets to route
through attacker-controlled nodes to leak TCP ISN and possibly other
protocol information.
While LSRR and SSRR are commonly filtered in many network environments,
they may still be supported and forwarded along some network paths.
RFC 7126 (Recommendations on Filtering of IPv4 Packets Containing
IPv4 Options) recommend to drop these options in 4.3 and 4.4.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: Tamir Shahar <tamirthesis@gmail.com>
Reported-by: Amit Klein <aksecurity@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260602161547.2642155-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
syzbot reported a weird reqsk->rsk_refcnt underflow in
__inet_csk_reqsk_queue_drop().
The captured reqsk_put() in __inet_csk_reqsk_queue_drop()
is called only when it successfully removes reqsk from ehash.
Moreover, reqsk_timer_handler() calls another reqsk_put()
after that.
This indicates that the reqsk was missing both refcnts for
ehash and the timer itself.
Since all the syzbot reports had PREEMPT_RT enabled, the only
possible scenario is that reqsk_queue_hash_req() is preempted
after mod_timer() and before refcount_set(), and then the timer
triggered after 1s aborts the reqsk due to its listener's close().
Let's wrap mod_timer() and refcount_set() with
preempt_disable_nested() and preempt_enable_nested().
Note that inet_ehash_insert() holds the normal spin_lock()
(mutex in PREEMPT_RT), so it must be called outside of
preempt_disable_nested(), but this is fine.
The lookup path just ignores 0 sk_refcnt entries in ehash
and tries to create another reqsk, but this will fail at
inet_ehash_insert().
[0]:
refcount_t: underflow; use-after-free.
WARNING: lib/refcount.c:28 at refcount_warn_saturate+0xb2/0x110 lib/refcount.c:28, CPU#0: ktimers/0/16
Modules linked in:
CPU: 0 UID: 0 PID: 16 Comm: ktimers/0 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:refcount_warn_saturate+0xb2/0x110 lib/refcount.c:28
Code: e4 7d d1 0a 67 48 0f b9 3a eb 4a e8 38 3d 23 fd 48 8d 3d e1 7d d1 0a 67 48 0f b9 3a eb 37 e8 25 3d 23 fd 48 8d 3d de 7d d1 0a <67> 48 0f b9 3a eb 24 e8 12 3d 23 fd 48 8d 3d db 7d d1 0a 67 48 0f
RSP: 0000:ffffc90000157948 EFLAGS: 00010246
RAX: ffffffff84a1301b RBX: 0000000000000003 RCX: ffff88801ca98000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffffffff8f72ae00
RBP: ffffffff99ae3b01 R08: ffff88801ca98000 R09: 0000000000000005
R10: 0000000000000100 R11: 0000000000000004 R12: ffff8880425ef568
R13: ffff8880425ef4f8 R14: ffff8880425ef578 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888126386000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7b46710e9c CR3: 000000000dbb6000 CR4: 00000000003526f0
Call Trace:
<TASK>
__refcount_sub_and_test include/linux/refcount.h:400 [inline]
__refcount_dec_and_test include/linux/refcount.h:432 [inline]
refcount_dec_and_test include/linux/refcount.h:450 [inline]
reqsk_put include/net/request_sock.h:136 [inline]
__inet_csk_reqsk_queue_drop+0x3ce/0x440 net/ipv4/inet_connection_sock.c:1007
reqsk_timer_handler+0x651/0xdf0 net/ipv4/inet_connection_sock.c:1137
call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2374 [inline]
__run_timer_base+0x6a3/0x9f0 kernel/time/timer.c:2386
run_timer_base kernel/time/timer.c:2395 [inline]
run_timer_softirq+0x67/0x170 kernel/time/timer.c:2403
handle_softirqs+0x1de/0x6d0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
run_ktimerd+0x69/0x100 kernel/softirq.c:1151
smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Fixes: d2d6422f8b ("x86: Allow to enable PREEMPT_RT.")
Reported-by: syzbot+e809069bc15f26300526@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/6a1a7bcf.0a9e871e.332604.000b.GAE@google.com/
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20260601182101.3183993-1-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Steffen Klassert says:
====================
pull request (net): ipsec 2026-05-29
1) xfrm: route MIGRATE notifications to caller's netns
Thread the caller's netns through km_migrate() so that
MIGRATE notifications go to the issuing netns, fixing both the
init_net listener leak and MOBIKE notifications inside
non-init netns. From Maoyi Xie.
2) xfrm: ipcomp: Free destination pages on acomp errors
Move the out_free_req label up so that allocated destination
pages are released on decompression errors, not only on success.
From Herbert Xu.
3) xfrm: Check for underflow in xfrm_state_mtu
Reject configurations that cause xfrm_state_mtu() to underflow,
preventing a negative TFCPAD value from becoming a memset size
that triggers an out-of-bounds write of several terabytes.
From David Ahern.
4) xfrm: ah: use skb_to_full_sk in async output callbacks
Convert the possibly-incomplete skb->sk to a full socket pointer
in async AH callbacks so that a request_sock or timewait_sock
never reaches xfrm_output_resume() downstream consumers.
From Michael Bommarito.
5) Add and revert: esp: fix page frag reference leak on skb_to_sgvec failure
The patch does not fix te issue completely.
6) xfrm: esp: restore combined single-frag length gate
Check the aligned post-trailer combined length against a page limit
in the fast path, preventing skb_page_frag_refill() from falling
back to a page too small for the destination scatterlist.
From Jingguo Tan.
7) xfrm: iptfs: reset runtime state when cloning SAs
Reinitialise the clone's mode_data runtime objects before
publishing it, preventing queued skbs from being freed with
list state copied from the original SA when migration fails.
From Shaomin Chen.
8) xfrm: move policy_bydst RCU sync from per-netns .exit to .pre_exit
Flush policy tables and drain the workqueue in a .pre_exit handler
so that cleanup_net() pays one RCU grace period per batch instead
of one per namespace, fixing stalls at high CLONE_NEWNET rates.
From Usama Arif.
9) xfrm: input: hold netns during deferred transport reinjection
Take a netns reference when queueing deferred transport reinjection
work and drop it after the callback completes, keeping the skb->cb
net pointer valid until the deferred work runs.
From Zhengchuan Liang.
* tag 'ipsec-2026-05-29' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec:
Revert "esp: fix page frag reference leak on skb_to_sgvec failure"
xfrm: input: hold netns during deferred transport reinjection
xfrm: move policy_bydst RCU sync from per-netns .exit to .pre_exit
xfrm: iptfs: reset runtime state when cloning SAs
xfrm: esp: restore combined single-frag length gate
esp: fix page frag reference leak on skb_to_sgvec failure
xfrm: ah: use skb_to_full_sk in async output callbacks
xfrm: Check for underflow in xfrm_state_mtu
xfrm: ipcomp: Free destination pages on acomp errors
xfrm: route MIGRATE notifications to caller's netns
====================
Link: https://patch.msgid.link/20260529092648.3878973-1-steffen.klassert@secunet.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This reverts commit 2982e599ff.
The patch does not fully fix the issue and the Author does
not match the 'Signed-off-by:' tag, so revert it for now.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
In some cases, iptunnel_pmtud_check_icmp() can be called while
skb transport header is not set.
This triggers an out-of-bound access, because
(typeof(skb->transport_header))~0U is 65535.
Access the icmp header based on IPv4 network header,
after making sure icmp->type is present in skb linear part.
Note that iptunnel_pmtud_check_icmpv6()) is fine.
Fixes: 4cb47a8644 ("tunnels: PMTU discovery support for directly bridged IP packets")
Reported-by: Damiano Melotti <melotti@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260522115512.1519110-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Sashiko found that iptunnel_pmtud_build_icmp() and
iptunnel_pmtud_build_icmpv6() were caching ip_hdr() and ipv6_hdr()
before an skb_cow() call which can reallocate skb->head.
Fix this possible UAF by initializing the local variables
after the skb_cow() call.
Remove skb_reset_network_header() calls which were not needed.
Fixes: 4cb47a8644 ("tunnels: PMTU discovery support for directly bridged IP packets")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Link: https://patch.msgid.link/20260525201335.2361845-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The ESP out-of-place fast path appends the trailer in esp_output_head()
before esp_output_tail() allocates the destination page frag. The
head-side gate currently checks skb->data_len and tailen separately, but
the tail code allocates a single destination frag from the combined
post-trailer skb->data_len.
Reject the page-frag fast path when the combined aligned length exceeds a
page. Otherwise skb_page_frag_refill() may fall back to a single page while
the destination sg still spans the combined skb->data_len.
Restore this combined-length page gate for both IPv4 and IPv6.
Fixes: 5bd8baab08 ("esp: limit skb_page_frag_refill use to a single page")
Cc: stable@vger.kernel.org
Signed-off-by: Lin Ma <malin89@huawei.com>
Signed-off-by: Chenyuan Mi <michenyuan@huawei.com>
Signed-off-by: Jingguo Tan <tanjingguo@huawei.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
In esp_output_tail(), when esp->inplace is false, the old skb page frags
are replaced with a new page from the xfrm page_frag cache. The source
scatterlist (sg) is built from the old frags before the replacement, and
esp_ssg_unref() is responsible for releasing the old page references
after the crypto operation completes.
However, if the second skb_to_sgvec() call (which builds the destination
scatterlist from the new page) fails, the code jumps to error_free which
only calls kfree(tmp). The old page frag references captured in the
source scatterlist are never released:
1. sg[] is built from old frags via skb_to_sgvec() (no extra get_page)
2. nr_frags is set to 1 and frag[0] is replaced with the new page
3. Second skb_to_sgvec() fails -> goto error_free
4. kfree(tmp) frees the sg[] memory but old frags are not unref'd
5. kfree_skb() only releases frag[0] (the new page), not the old ones
Fix this by adding a bool parameter to esp_ssg_unref() that, when true,
unconditionally unrefs the source scatterlist frags without checking
req->src and req->dst, since those fields are not yet initialized by
aead_request_set_crypt() at the point of the error. Existing callers
pass false to preserve the original behavior.
The same issue exists in both esp4 and esp6 as the code is identical.
Fixes: cac2661c53 ("esp4: Avoid skb_cow_data whenever possible")
Fixes: 03e2a30f6a ("esp6: Avoid skb_cow_data whenever possible")
Signed-off-by: Alessandro Schino <7991aleschino@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Two frag-transfer helpers (__pskb_copy_fclone() and skb_shift()) fail
to propagate the SKBFL_SHARED_FRAG bit in skb_shinfo()->flags when
moving frags from source to destination. __pskb_copy_fclone() defers
the rest of the shinfo metadata to skb_copy_header() after copying
frag descriptors, but that helper only carries over gso_{size,segs,
type} and never touches skb_shinfo()->flags; skb_shift() moves frag
descriptors directly and leaves flags untouched. As a result, the
destination skb keeps a reference to the same externally-owned or
page-cache-backed pages while reporting skb_has_shared_frag() as
false.
The mismatch is harmful in any in-place writer that uses
skb_has_shared_frag() to decide whether shared pages must be detoured
through skb_cow_data(). ESP input is one such writer (esp4.c,
esp6.c), and a single nft 'dup to <local>' rule -- or any other
nf_dup_ipv4() / xt_TEE caller -- is enough to land a pskb_copy()'d
skb in esp_input() with the marker stripped, letting an unprivileged
user write into the page cache of a root-owned read-only file via
authencesn-ESN stray writes.
Set SKBFL_SHARED_FRAG on the destination whenever frag descriptors
were actually moved from the source. skb_copy() and skb_copy_expand()
share skb_copy_header() too but linearize all paged data into freshly
allocated head storage and emerge with nr_frags == 0, so
skb_has_shared_frag() returns false on its own; they need no change.
The same omission exists in skb_gro_receive() and skb_gro_receive_list().
The former moves the incoming skb's frag descriptors into the
accumulator's last sub-skb via two paths (a direct frag-move loop and
the head_frag + memcpy path); the latter chains the incoming skb whole
onto p's frag_list. Downstream skb_segment() reads only
skb_shinfo(p)->flags, and skb_segment_list() reuses each sub-skb's
shinfo as the nskb -- both p and lp must carry the marker.
The same omission also exists in tcp_clone_payload(), which builds an
MTU probe skb by moving frag descriptors from skbs on sk_write_queue
into a freshly allocated nskb. The helper falls into the same family
and warrants the same fix for consistency; no TCP TX-side in-place
writer is currently known to reach a user page through this gap, but
a future consumer depending on the marker would regress silently.
The same omission exists in skb_segment(): the per-iteration flag
merge takes only head_skb's flag, and the inner switch that rebinds
frag_skb to list_skb on head_skb-frags exhaustion does not fold the
new frag_skb's flag into nskb. Fold frag_skb's flag at both sites
so segments drawing frags from frag_list members carry the marker.
Fixes: cef401de7b ("net: fix possible wrong checksum generation")
Fixes: f4c50a4034 ("xfrm: esp: avoid in-place decrypt on shared skb frags")
Suggested-by: Sabrina Dubroca <sd@queasysnail.net>
Suggested-by: Sultan Alsawaf <sultan@kerneltoast.com>
Suggested-by: Ben Hutchings <ben@decadent.org.uk>
Suggested-by: Lin Ma <malin89@huawei.com>
Suggested-by: Jingguo Tan <tanjingguo@huawei.com>
Suggested-by: Aaron Esau <aaron1esau@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com>
Tested-by: Rajat Gupta <rajat.gupta@oss.qualcomm.com>
Link: https://patch.msgid.link/ageeJfJHwgzmKXbh@v4bel
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Blamed commit moved the TIME_WAIT-derived ISN from the skb control
block to a per-CPU variable, assuming the value would always be consumed
by tcp_conn_request() for the same packet that wrote it. That assumption
is violated by multiple drop paths between the producer
(__this_cpu_write(tcp_tw_isn, isn) in tcp_v{4,6}_rcv()) and the consumer
(tcp_conn_request()):
- min_ttl / min_hopcount check
- xfrm policy check
- tcp_inbound_hash() MD5/AO mismatch
- tcp_filter() eBPF/SO_ATTACH_FILTER drop
- th->syn && th->fin discard in tcp_rcv_state_process() TCP_LISTEN
- psp_sk_rx_policy_check() in tcp_v{4,6}_do_rcv()
- tcp_checksum_complete() in tcp_v{4,6}_do_rcv()
- tcp_v{4,6}_cookie_check() returning NULL
When a packet is dropped on any of these paths, tcp_tw_isn is left set.
The next SYN processed on the same CPU then consumes the non zero value in
tcp_conn_request(), receiving a potentially predictable ISN.
This patch moves back tcp_tw_isn to skb->cb[], getting rid of the per-cpu
variable.
Note that tcp_v{4,6}_fill_cb() do not set it.
Very litle impact on overall code size/complexity:
$ scripts/bloat-o-meter -t vmlinux.old vmlinux.new
add/remove: 0/0 grow/shrink: 2/1 up/down: 8/-15 (-7)
Function old new delta
tcp_v6_rcv 3038 3042 +4
tcp_v4_rcv 3035 3039 +4
tcp_conn_request 2938 2923 -15
Total: Before=24436060, After=24436053, chg -0.00%
Fixes: 41eecbd712 ("tcp: replace TCP_SKB_CB(skb)->tcp_tw_isn with a per-cpu field")
Reported-by: Chris Mason <clm@meta.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260519084611.2485277-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The cited commit started using msslen for uh->len, but still uses newlen
to adjust uh->check. Although the checksum is ignored in most cases due
to the hardware offload, __udp_gso_segment attempts to maintain the
correct one. Fix uh->check and adjust it by the right value.
Additionally, after the fix, newlen becomes assigned and unused before
the loop. The code can be simplified a bit if mss adjustment is dropped,
so that newlen becomes equal to msslen before the loop, and msslen can
be also dropped, saving a few lines of code.
This brings us back to one variable, drops an unneeded arithmetic for
mss, and fixes the UDP checksum.
Fixes: b10b446ce7 ("udp: gso: Use single MSS length in UDP header for GSO_PARTIAL")
Signed-off-by: Alice Mikityanska <alice@isovalent.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Gal Pressman <gal@nvidia.com>
Link: https://patch.msgid.link/20260518062250.3019914-2-gal@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When AH output is offloaded to an asynchronous crypto provider
(hardware accelerators such as AMD CCP, or a forced-async software
shim used for testing), the digest completion fires
ah_output_done() / ah6_output_done() on a workqueue. The egress
skb at that point may have been originated by a TCP listener
sending a SYN-ACK, which sets skb->sk to a request_sock via
skb_set_owner_edemux(); it may also have been originated by an
inet_timewait_sock retransmit. Neither is a full struct sock, and
passing the raw skb->sk to xfrm_output_resume() then forwards a
non-full socket through the rest of the xfrm output chain.
xfrm_output_resume() and its downstream consumers expect a full
sk where they dereference at all. The natural egress path
through ah_output_done() does not crash today because the
consumers that read past sock_common are either gated by
sk_fullsock() or short-circuit on flags that are clear on a fresh
request_sock; an exhaustive walk of the 50 most plausible
consumers under sch_fq, dev_queue_xmit, netfilter, tc-egress and
cgroup-egress BPF found no current unguarded deref. The bug is
still a real type confusion that future consumer changes could
turn into a memory-corruption primitive.
This is the same bug class fixed for ESP in commit 1620c88887
("xfrm: Fix the usage of skb->sk"). Apply the analogous fix to
AH: convert skb->sk to a full socket pointer (or NULL) via
skb_to_full_sk() before handing it to xfrm_output_resume().
The same async AH callbacks were touched recently for an
independent ESN-related ICV layout bug in commit ec54093e6a
("xfrm: ah: account for ESN high bits in async callbacks"); the
sk type-confusion addressed here is orthogonal. This patch is
part of an ongoing audit of the AH callback paths; an ah_output
ihl-validation hardening series is also currently under review on
netdev.
Reproduced under UML + KASAN + lockdep with a forced-async
hmac(sha1) shim that registers at priority 9999 and wraps the
sync in-tree hmac-sha1-lib. With the shim loaded, ah_output_done
runs on every SYN-ACK egress through a transport-mode AH SA and
skb->sk arrives as a request_sock (TCP_NEW_SYN_RECV); after this
patch, xfrm_output_resume() receives the listener (the result of
sk_to_full_sk()) and consumer derefs land on full-sock fields as
intended.
Fixes: 9ab1265d52 ("xfrm: Use actual socket sk instead of skb socket for xfrm_output_resume")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
raw_send_hdrinc() validates that the caller-supplied IPv4 header
fits within the message length:
iphlen = iph->ihl * 4;
err = -EINVAL;
if (iphlen > length)
goto error_free;
if (iphlen >= sizeof(*iph)) {
/* fix up saddr, tot_len, id, csum, transport_header */
}
It does not, however, reject ihl < 5. For such a packet the
"if (iphlen >= sizeof(*iph))" branch is skipped, leaving the
crafted iphdr untouched, but the packet is still handed to
__ip_local_out() and onward. Downstream consumers that read
iph->ihl assume a sane value: net/ipv4/ah4.c:ah_output() in
particular subtracts sizeof(struct iphdr) from top_iph->ihl * 4
and passes the (signed-int-negative, then cast to size_t)
result to memcpy(), producing an OOB access of length close to
SIZE_MAX and a host kernel panic.
An IPv4 header with ihl < 5 is malformed by definition (RFC 791:
"Internet Header Length is the length of the internet header in
32 bit words ... Note that the minimum value for a correct header
is 5."). The kernel should not be willing to inject such a
packet into its own output path.
Reject "iphlen < sizeof(*iph)" alongside the existing
"iphlen > length" check. This matches the principle that locally
constructed packets that re-enter the IP stack must pass the same
basic sanity tests that a foreign packet would be subjected to.
Once this lands, the "if (iphlen >= sizeof(*iph))" wrapper around
the fixup branch becomes redundant; left in place to keep the
patch minimal and backport-friendly. A follow-up can unwrap it.
Note that commit 86f4c90a1c ("ipv4, ipv6: ensure raw socket
message is big enough to hold an IP header") ensures the message
buffer is large enough to hold an iphdr, but does not constrain
the self-reported iph->ihl.
Reachability: the malformed packet source is any caller with
CAP_NET_RAW, including an unprivileged process in a user+net
namespace on a kernel with CONFIG_USER_NS=y. The reproduced AH
crash also requires a matching xfrm AH policy on the outgoing
route; a container granted CAP_NET_ADMIN can install that state
and policy in its netns. Loopback bypasses xfrm_output, so the
trigger uses a real netdev.
Reproduced on UML + KASAN: kernel-mode fault at addr 0x0 with
memcpy_orig at the crash site. Same shape reproduces inside a
rootless Docker container with --cap-add NET_ADMIN on a stock
distro kernel.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Suggested-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Link: https://patch.msgid.link/77ec2b5e8111961c2c39883c92e8aa2709039c17.1778614451.git.michael.bommarito@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Pull networking fixes from Paolo Abeni:
"Including fixes from netfilter.
Previous releases - regressions:
- ethtool: fix NULL pointer dereference in phy_reply_size
- netfilter:
- allocate hook ops while under mutex
- close dangling table module init race
- restore nf_conntrack helper propagation via expectation
- tcp:
- fix potential UAF in reqsk_timer_handler().
- fix out-of-bounds access for twsk in tcp_ao_established_key().
- vsock: fix empty payload in tap skb for non-linear buffers
- hsr: fix NULL pointer dereference in hsr_get_node_data()
- eth:
- cortina: fix RX drop accounting
- ice: fix locking in ice_dcb_rebuild()
Previous releases - always broken:
- napi: avoid gro timer misfiring at end of busypoll
- sched:
- dualpi2: initialize timer earlier in dualpi2_init()
- sch_cbs: Call qdisc_reset for child qdisc
- shaper:
- fix ordering issue in net_shaper_commit()
- reject handle IDs exceeding internal bit-width
- ipv6: flowlabel: enforce per-netns limit for unprivileged callers
- tls: fix off-by-one in sg_chain entry count for wrapped sk_msg ring
- smc: avoid NULL deref of conn->lnk in smc_msg_event tracepoint
- sctp: revalidate list cursor after sctp_sendmsg_to_asoc() in SCTP_SENDALL
- batman-adv:
- reject new tp_meter sessions during teardown
- purge non-released claims
- eth:
- i40e: cleanup PTP registration on probe failure
- idpf: fix double free and use-after-free in aux device error paths
- ena: fix potential use-after-free in get_timestamp"
* tag 'net-7.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (88 commits)
net: phy: DP83TC811: add reading of abilities
net: tls: prevent chain-after-chain in plain text SG
net: tls: fix off-by-one in sg_chain entry count for wrapped sk_msg ring
net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot
macsec: use rcu_work to defer TX SA crypto cleanup out of softirq
macsec: use rcu_work to defer RX SA crypto cleanup out of softirq
macsec: introduce dedicated workqueue for SA crypto cleanup
net: net_failover: Fix the deadlock in slave register
MAINTAINERS: update atlantic driver maintainer
selftests/tc-testing: Add QFQ/CBS qlen underflow test
net/sched: sch_cbs: Call qdisc_reset for child qdisc
FDDI: defza: Sanitise the reset safety timer
net: ethernet: ravb: Do not check URAM suspension when WoL is active
ethtool: fix ethnl_bitmap32_not_zero() bit interval semantics
net/smc: avoid NULL deref of conn->lnk in smc_msg_event tracepoint
net/smc: fix sleep-inside-lock in __smc_setsockopt() causing local DoS
net: atm: fix skb leak in sigd_send() default branch
net: ethtool: phy: avoid NULL deref when PHY driver is unbound
net: atlantic: preserve PCI wake-from-D3 on shutdown when WOL enabled
net: shaper: reject QUEUE scope handle with missing id
...
lockdep_sock_is_held() was added in tcp_ao_established_key()
by the cited commit.
It can be called from tcp_v[46]_timewait_ack() with twsk.
Since it does not have sk->sk_lock, the lockdep annotation
results in out-of-bound access.
$ pahole -C tcp_timewait_sock vmlinux | grep size
/* size: 288, cachelines: 5, members: 8 */
$ pahole -C sock vmlinux | grep sk_lock
socket_lock_t sk_lock; /* 440 192 */
Let's not use lockdep_sock_is_held() for TCP_TIME_WAIT.
Fixes: 6b2d11e2d8 ("net/tcp: Add missing lockdep annotations for TCP-AO hlist traversals")
Reported-by: Damiano Melotti <melotti@google.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260508120853.4098365-1-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Pablo Neira Ayuso says:
====================
Netfilter fixes for net
The following batch contains Netfilter fixes for net:
1) Allow initial x_tables table replacement without emitting an audit
log message. Delay the register message until after hooks are wired up
to avoid unnecessary unregister logs during error unwinding.
2) Fix a NULL dereference by allocating hook ops before adding the
table to the per-netns list. Use `synchronize_rcu()` during error
unwinding to ensure the table stops processing packets before
teardown. Defer audit log register message until all operations
succeed.
3) Refactor xtables to use a single `xt_unregister_table_pre_exit`
function. Eliminate code duplication by centralizing table
unregistration logic within the xtables core. ebtables cannot be
changed due to incompatibility.
4) Unregister xtables templates before module removal. This prevents
a race condition where userspace instantiates a new table after the
pernet unreg removed the current table.
5) Add `xtables_unregister_table_exit` to fully unregister netfilter
tables during module removal. Unlink the table from dying lists,
then free hook operations.
6) Implement a two-stage removal scheme for ebtables following the
x_tables pattern. Assign table->ops while holding the ebt mutex to
prevent exposing partially-filled structures.
7) Fix ebtables module initialization race. Register the template last
in table initialization functions. Prevent table instantiation before
pernet operations are available.
8) Fix a race condition in x_tables module initialization. Ensure
pernet ops are fully set up before exposing the table to userspace.
9) Fix a race condition in ebtables module initialization, similar to
previous patch.
10) Restore propagation of helper to expected connection, this is a
fix-for-recent-fix.
11) Validate that the expectation tuple and mask netlink attributes are
present when adding expectation via nfqueue, this fixes a possible
null-ptr-deref.
12) Fix possible rare memleak in the SIP helper in case helper has been
detached from conntrack entry, from Li Xiasong.
13) Fix refcount leak in nft_ct when creating custom expectation, also
from Li Xiason.
Patches 1-9 from Florian Westphal.
10) Restore propagation of helper to expected connection, this is a
fix-for-recent-fix.
11) Check that tuple and mask netlink attributes are set when creating an
expectation via nfqueue.
* tag 'nf-26-05-08' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
netfilter: nft_ct: fix missing expect put in obj eval
netfilter: nf_conntrack_sip: get helper before allocating expectation
netfilter: ctnetlink: check tuple and mask in expectations created via nfqueue
netfilter: nf_conntrack_expect: restore helper propagation via expectation
netfilter: bridge: eb_tables: close module init race
netfilter: x_tables: close dangling table module init race
netfilter: ebtables: close dangling table module init race
netfilter: ebtables: move to two-stage removal scheme
netfilter: x_tables: add and use xtables_unregister_table_exit
netfilter: x_tables: unregister the templates first
netfilter: x_tables: add and use xt_unregister_table_pre_exit
netfilter: x_tables: allocate hook ops while under mutex
netfilter: x_tables: allow initial table replace without emitting audit log message
====================
Link: https://patch.msgid.link/20260507234509.603182-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When TCP socket migration happens in reqsk_timer_handler(),
@sk_listener will be updated with the new listener.
When we call __inet_csk_reqsk_queue_drop(), the listener must
be the one stored in req->rsk_listener.
The cited commit accidentally replaced oreq->rsk_listener with
sk_listener, leading to imbalanced icsk_accept_queue count.
Let's pass the correct listener to __inet_csk_reqsk_queue_drop().
Fixes: e8c526f2bd ("tcp/dccp: Don't use timer_pending() in reqsk_queue_unlink().")
Reported-by: Damiano Melotti <melotti@google.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260506035954.1563147-3-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When TCP socket migration fails at inet_ehash_insert() in
reqsk_timer_handler(), we jump to the no_ownership: label
and free the new reqsk immediately with __reqsk_free().
Thus, we must stop the new reqsk's timer before jumping to the
label, but the timer might be missed since the cited commit,
resulting in UAF.
As we are in the original reqsk's timer context, we can safely
call timer_delete_sync() for the new reqsk.
Let's pass false to __inet_csk_reqsk_queue_drop() to stop
the new reqsk's timer.
Fixes: 83fccfc394 ("inet: fix potential deadlock in reqsk_queue_unlink()")
Reported-by: Damiano Melotti <melotti@google.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260506035954.1563147-2-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Similar to the previous ebtables patch:
template add exposes the table to userspace, we must do this last to
rnsure the pernet ops are set up (contain the destructors).
Fixes: fdacd57c79 ("netfilter: x_tables: never register tables by default")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Previous change added xtables_unregister_table_pre_exit to detach the
table from the packetpath and to unlink it from the active table list.
In case of rmmod, userspace that is doing set/getsockopt for this table
will not be able to re-instantiate the table:
1. The larval table has been removed already
2. existing instantiated table is no longer on the xt pernet table list.
This adds the second stage helper:
unlink the table from the dying list, free the hook ops (if any) and do
the audit notification. It replaces xt_unregister_table().
Fixes: fdacd57c79 ("netfilter: x_tables: never register tables by default")
Reported-by: Tristan Madani <tristan@talencesecurity.com>
Reviewed-by: Tristan Madani <tristan@talencesecurity.com>
Closes: https://lore.kernel.org/netfilter-devel/20260429175613.1459342-1-tristmd@gmail.com/
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Remove the copypasted variants of _pre_exit and add one single
function in the xtables core. ebtables is not compatible with
x_tables and therefore unchanged.
This is a preparation patch to reduce noise in the followup
bug fixes.
Reviewed-by: Tristan Madani <tristan@talencesecurity.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
arp/ip(6)t_register_table() add the table to the per-netns list via
xt_register_table() before allocating the per-netns hook ops copy
via kmemdup_array(). This leaves a window where the table is
visible in the list with ops=NULL.
If the pernet exit happens runs concurrently the pre_exit callback finds
the table via xt_find_table() and passes the NULL ops pointer to
nf_unregister_net_hooks(), causing a NULL dereference:
general protection fault in nf_unregister_net_hooks+0xbc/0x150
RIP: nf_unregister_net_hooks (net/netfilter/core.c:613)
Call Trace:
ipt_unregister_table_pre_exit
iptable_mangle_net_pre_exit
ops_pre_exit_list
cleanup_net
Fix by moving the ops allocation into the xtables core so the table is
never in the list without valid ops. Also ensure the table is no longer
processing packets before its torn down on error unwind.
nf_register_net_hooks might have published at least one hook; call
synchronize_rcu() if there was an error.
audit log register message gets deferred until all operations have
passed, this avoids need to emit another ureg message in case of
error unwinding.
Based on earlier patch by Tristan Madani.
Fixes: f9006acc8d ("netfilter: arp_tables: pass table pointer via nf_hook_ops")
Fixes: ee177a5441 ("netfilter: ip6_tables: pass table pointer via nf_hook_ops")
Fixes: ae68933422 ("netfilter: ip_tables: pass table pointer via nf_hook_ops")
Link: https://lore.kernel.org/netfilter-devel/20260429175613.1459342-1-tristmd@gmail.com/
Signed-off-by: Tristan Madani <tristan@talencesecurity.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
tcp_child_process( .. child ...) currently calls sock_put(child).
Unfortunately @child (named @nsk in callers) can be used after
this point to send a RST packet.
To fix this UAF, I remove the sock_put() from tcp_child_process()
and let the callers handle this after it is safe.
Remove @rsk variable in tcp_v4_do_rcv() and change tcp_v6_do_rcv()
so that both functions look the same.
Fixes: cfb6eeb4c8 ("[TCP]: MD5 Signature Option (RFC2385) support.")
Reported-by: Damiano Melotti <melotti@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260505153927.3435532-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When performing a lockless lookup over the inet_peer rbtree,
if a matching node is found, inet_getpeer() returns it immediately
without validating the seqlock sequence.
This missing check introduces a race condition:
Trigger Path: When a host receives an incoming fragmented IPv4 packet,
ip4_frag_init() (in net/ipv4/ip_fragment.c) calls inet_getpeer_v4()
to track the peer.
The Race: If the packet is from a new source IP, CPU A acquires the
write_seqlock, allocates a new inet_peer node (p), sets its IP address
(daddr), and links it to the rbtree (rb_link_node).
Uninitialized Access: Due to the lack of memory barriers between
rb_link_node and the initialization of the rest of the struct
(like refcount_set(&p->refcnt, 1)), CPU A can make the node visible
to readers before its refcnt is initialized.
This is especially true on weakly-ordered architectures like ARM64
where the CPU can reorder the memory stores.
Lockless Reader: Concurrently, CPU B processes a second fragmented packet
from the same source IP. CPU B does a lockless lookup, finds the newly
inserted node, and returns it immediately.
Use-After-Free (UAF): CPU B reads p->refcnt as uninitialized garbage
(left over from previous kmalloc-128/192 allocations).
If the garbage is > 0, refcount_inc_not_zero(&p->refcnt) succeeds.
CPU A then executes refcount_set(&p->refcnt, 1), overwriting CPU B's increment.
When CPU B finishes with the fragment queue, it calls inet_putpeer(),
which drops the refcount to 0 and frees the node via RCU.
The node is now freed but remains linked in the rbtree,
resulting in a Use-After-Free in the rbtree.
Fixes: b145425f26 ("inetpeer: remove AVL implementation in favor of RB tree")
Reported-by: Damiano Melotti <melotti@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260505133233.3039575-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Steffen Klassert says:
====================
pull request (net): ipsec 2026-05-05
1. Fix an IPv6 encapsulation error path that leaked route references
when UDPv6 ESP decapsulation resolved to an error route.
From Yilin Zhu.
2. Fix AH with ESN on async crypto paths by accounting for the extra
high-order sequence number when reconstructing the temporary
authentication layout in the completion callbacks.
From Michael Bomarito.
3. Fix XFRM output so it does not overwrite already-correct inner header
pointers when a tunnel layer such as VXLAN has already saved them.
The fix comes with new selftests. From Cosmin Ratiu.
4. Add the missing native payload size entry for XFRM_MSG_MAPPING in the
compat translation path. From Ruijie Li.
5. Harden __xfrm_state_delete() against repeated or inconsistent unhashing
of state list nodes by keying the removal on actual list membership and
using delete-and-init helpers. From Michal Kosiorek.
6. Prevent ESP from decrypting shared splice-backed skb fragments in place
by marking UDP splice frags as shared and forcing copy-on-write in ESP
input when needed. From Kuan-Ting Chen.
* tag 'ipsec-2026-05-05' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec:
xfrm: esp: avoid in-place decrypt on shared skb frags
xfrm: defensively unhash xfrm_state lists in __xfrm_state_delete
xfrm: provide message size for XFRM_MSG_MAPPING
xfrm: Don't clobber inner headers when already set
tools/selftests: Add a VXLAN+IPsec traffic test
tools/selftests: Use a sensible timeout value for iperf3 client
xfrm: ah: account for ESN high bits in async callbacks
ipv6: xfrm6: release dst on error in xfrm6_rcv_encap()
====================
Link: https://patch.msgid.link/20260505132326.1362733-1-steffen.klassert@secunet.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
MSG_SPLICE_PAGES can attach pages from a pipe directly to an skb. TCP
marks such skbs with SKBFL_SHARED_FRAG after skb_splice_from_iter(),
so later paths that may modify packet data can first make a private
copy. The IPv4/IPv6 datagram append paths did not set this flag when
splicing pages into UDP skbs.
That leaves an ESP-in-UDP packet made from shared pipe pages looking
like an ordinary uncloned nonlinear skb. ESP input then takes the no-COW
fast path for uncloned skbs without a frag_list and decrypts in place
over data that is not owned privately by the skb.
Mark IPv4/IPv6 datagram splice frags with SKBFL_SHARED_FRAG, matching
TCP. Also make ESP input fall back to skb_cow_data() when the flag is
present, so ESP does not decrypt externally backed frags in place.
Private nonlinear skb frags still use the existing fast path.
This intentionally does not change ESP output. In esp_output_head(),
the path that appends the ESP trailer to existing skb tailroom without
calling skb_cow_data() is not reachable for nonlinear skbs:
skb_tailroom() returns zero when skb->data_len is nonzero, while ESP
tailen is positive. Thus ESP output will either use the separate
destination-frag path or fall back to skb_cow_data().
Fixes: cac2661c53 ("esp4: Avoid skb_cow_data whenever possible")
Fixes: 03e2a30f6a ("esp6: Avoid skb_cow_data whenever possible")
Fixes: 7da0dde684 ("ip, udp: Support MSG_SPLICE_PAGES")
Fixes: 6d8192bd69 ("ip6, udp6: Support MSG_SPLICE_PAGES")
Reported-by: Hyunwoo Kim <imv4bel@gmail.com>
Reported-by: Kuan-Ting Chen <h3xrabbit@gmail.com>
Tested-by: Hyunwoo Kim <imv4bel@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Kuan-Ting Chen <h3xrabbit@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Yiming Qian reported:
<quote>
ipmr_cache_report()` allocates a report skb with `alloc_skb(128,
GFP_ATOMIC)` and appends a `struct igmphdr` using `skb_put()`. In the
non-`IGMPMSG_WHOLEPKT` path it initializes only:
- `igmp->type`
- `igmp->code`
but does not initialize:
- `igmp->csum`
- `igmp->group`
Later, `igmpmsg_netlink_event()` copies the bytes after `sizeof(struct
igmpmsg)` into the `IPMRA_CREPORT_PKT` netlink attribute and emits
`RTM_NEWCACHEREPORT` on `RTNLGRP_IPV4_MROUTE_R`.
As a result, 6 bytes of stale heap data from the skb head are
disclosed to userspace.
</quote>
Let's use skb_put_zero() instead of skb_put() to fix this bug.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: Yiming Qian <yimingqian591@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260430070611.4004529-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Both nft_socket and xt_socket relies on L4 headers to perform socket
lookup in the slow path. For fragmented packets, while the IP protocol
remains constant across all fragments, only the first fragment contains
the actual L4 header.
As the expression/match could be attached to a chain with a priority
lower than -400, it could bypass defragmentation.
Add a check for fragmentation in the lookup functions directly so the
problem is handled for both nft_socket and xt_socket at the same time.
In addition, future users of the functions would not need to care about
this.
Fixes: 902d6a4c2a ("netfilter: nf_defrag: Skip defrag if NOTRACK is set")
Fixes: 554ced0a6e ("netfilter: nf_tables: add support for native socket matching")
Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Pablo Neira Ayuso says:
====================
Netfilter fixes for net
The following patchset contains Netfilter fixes for net:
1) IEEE1394 ARP payload contains no target hardware address in the
ARP packet. Apparently, arp_tables was never updated to deal with
IEEE1394 ARP properly. To deal with this, return no match in case
the target hardware address selector is used, either for inverse or
normal match. Moreover, arpt_mangle disallows mangling of the target
hardware and IP address because, it is not worth to adjust the
offset calculation to fix this, we suspect no users of arp_tables
for this family.
2) Use list_del_rcu() to delete device hooks in nf_tables, this hook
list is RCU protected, concurrent netlink dump readers can be
walking on this list, fix it by adding a helper function and use it
for consistency. From Florian Westphal.
3) Add list_splice_rcu(), this is useful for joining the local list of
new device hooks to the RCU protected hook list in chain and
flowtable. Reviewed by Paul E. McKenney.
4) Use list_splice_rcu() to publish the new device hooks in chain and
flowtable to fix concurrent netlink dump traversal.
5) Add a new hook transaction object to track device hook deletions.
The current approach moves device hooks to be deleted around during
the preparation phase, this breaks concurrent RCU reader via netlink
dump. This new hook transaction is combined with NFT_HOOK_REMOVE
flag to annotate hooks for removal in the preparation phase.
6) xt_policy inbound policy check in strict mode can lead to
out-of-bound access of the secpath array due to incorrect.
The iteration over the secpath needs to be reversed in the inbound
to check for the human readable policy, expecting inner in first
position and outer in second position, the secpath from inbound
actually stores outer in first position then in second position.
From Jiexun Wang.
7) Fix possible zero shift in nft_bitwise triggering UBSAN splat,
reject zero shift from control plane, from Kai Ma.
8) Replace simple_strtoul() in the conntrack SIP helper since it relies
on nul-terminated strings. From Florian Westphal.
* tag 'nf-26-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
netfilter: nf_conntrack_sip: don't use simple_strtoul
netfilter: reject zero shift in nft_bitwise
netfilter: xt_policy: fix strict mode inbound policy matching
netfilter: nf_tables: add hook transactions for device deletions
netfilter: nf_tables: join hook list via splice_list_rcu() in commit phase
rculist: add list_splice_rcu() for private lists
netfilter: nf_tables: use list_del_rcu for netlink hooks
netfilter: arp_tables: fix IEEE1394 ARP payload parsing
====================
Link: https://patch.msgid.link/20260428095840.51961-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
tcp_clamp_probe0_to_user_timeout() computes remaining time in jiffies
using subtraction with an unsigned lvalue. If elapsed probing time
exceeds the configured TCP_USER_TIMEOUT, the underflow yields a large
value.
This ends up re-arming the probe timer for a full backoff interval
instead of expiring immediately, delaying connection teardown beyond
the configured timeout.
Fix this by preventing underflow so user-set timeout expiration is
handled correctly without extending the probe timer.
Fixes: 344db93ae3 ("tcp: make TCP_USER_TIMEOUT accurate for zero window probes")
Link: https://lore.kernel.org/r/20260414013634.43997-1-ahacigu.linux@gmail.com
Signed-off-by: Altan Hacigumus <ahacigu.linux@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260424014639.54110-1-ahacigu.linux@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
With CONFIG_IP_MROUTE_MULTIPLE_TABLES=n, ipmr_fib_lookup()
does not check if net->ipv4.mrt is NULL.
Since default_device_exit_batch() is called after ->exit_rtnl(),
a device could receive IGMP packets and access net->ipv4.mrt
during/after ipmr_rules_exit_rtnl().
If ipmr_rules_exit_rtnl() had already cleared it and freed the
memory, the access would trigger null-ptr-deref or use-after-free.
Let's fix it by using RCU helper and free mrt after RCU grace
period.
In addition, check_net(net) is added to mroute_clean_tables()
and ipmr_cache_unresolved() to synchronise via mfc_unres_lock.
This prevents ipmr_cache_unresolved() from putting skb into
c->_c.mfc_un.unres.unresolved after mroute_clean_tables()
purges it.
For the same reason, timer_shutdown_sync() is moved after
mroute_clean_tables().
Since rhltable_destroy() holds mutex internally, rcu_work is
used, and it is placed as the first member because rcu_head
must be placed within <4K offset. mr_table is alraedy 3864
bytes without rcu_work.
Note that IP6MR is not yet converted to ->exit_rtnl(), so this
change is not needed for now but will be.
Fixes: b22b018674 ("ipmr: Convert ipmr_net_exit_batch() to ->exit_rtnl().")
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260423053456.4097409-1-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Pull networking deletions from Jakub Kicinski:
"Delete some obsolete networking code
Old code like amateur radio and NFC have long been a burden to core
networking developers. syzbot loves to find bugs in BKL-era code, and
noobs try to fix them.
If we want to have a fighting chance of surviving the LLM-pocalypse
this code needs to find a dedicated owner or get deleted. We've talked
about these deletions multiple times in the past and every time
someone wanted the code to stay. It is never very clear to me how many
of those people actually use the code vs are just nostalgic to see it
go. Amateur radio did have occasional users (or so I think) but most
users switched to user space implementations since its all super slow
stuff. Nobody stepped up to maintain the kernel code.
We were lucky enough to find someone who wants to help with NFC so
we're giving that a chance. Let's try to put the rest of this code
behind us"
* tag 'net-deletions' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next:
drivers: net: 8390: wd80x3: Remove this driver
drivers: net: 8390: ultra: Remove this driver
drivers: net: 8390: AX88190: Remove this driver
drivers: net: fujitsu: fmvj18x: Remove this driver
drivers: net: smsc: smc91c92: Remove this driver
drivers: net: smsc: smc9194: Remove this driver
drivers: net: amd: nmclan: Remove this driver
drivers: net: amd: lance: Remove this driver
drivers: net: 3com: 3c589: Remove this driver
drivers: net: 3com: 3c574: Remove this driver
drivers: net: 3com: 3c515: Remove this driver
drivers: net: 3com: 3c509: Remove this driver
net: packetengines: remove obsolete yellowfin driver and vendor dir
net: packetengines: remove obsolete hamachi driver
net: remove unused ATM protocols and legacy ATM device drivers
net: remove ax25 and amateur radio (hamradio) subsystem
net: remove ISDN subsystem and Bluetooth CMTP
caif: remove CAIF NETWORK LAYER
Pull networking fixes from Jakub Kicinski:
"Including fixes from Netfilter.
Steady stream of fixes. Last two weeks feel comparable to the two
weeks before the merge window. Lots of AI-aided bug discovery. A newer
big source is Sashiko/Gemini (Roman Gushchin's system), which points
out issues in existing code during patch review (maybe 25% of fixes
here likely originating from Sashiko). Nice thing is these are often
fixed by the respective maintainers, not drive-bys.
Current release - new code bugs:
- kconfig: MDIO_PIC64HPSC should depend on ARCH_MICROCHIP
Previous releases - regressions:
- add async ndo_set_rx_mode and switch drivers which we promised to
be called under the per-netdev mutex to it
- dsa: remove duplicate netdev_lock_ops() for conduit ethtool ops
- hv_sock: report EOF instead of -EIO for FIN
- vsock/virtio: fix MSG_PEEK calculation on bytes to copy
Previous releases - always broken:
- ipv6: fix possible UAF in icmpv6_rcv()
- icmp: validate reply type before using icmp_pointers
- af_unix: drop all SCM attributes for SOCKMAP
- netfilter: fix a number of bugs in the osf (OS fingerprinting)
- eth: intel: fix timestamp interrupt configuration for E825C
Misc:
- bunch of data-race annotations"
* tag 'net-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (148 commits)
rxrpc: Fix error handling in rxgk_extract_token()
rxrpc: Fix re-decryption of RESPONSE packets
rxrpc: Fix rxrpc_input_call_event() to only unshare DATA packets
rxrpc: Fix missing validation of ticket length in non-XDR key preparsing
rxgk: Fix potential integer overflow in length check
rxrpc: Fix conn-level packet handling to unshare RESPONSE packets
rxrpc: Fix potential UAF after skb_unshare() failure
rxrpc: Fix rxkad crypto unalignment handling
rxrpc: Fix memory leaks in rxkad_verify_response()
net: rds: fix MR cleanup on copy error
m68k: mvme147: Make me the maintainer
net: txgbe: fix firmware version check
selftests/bpf: check epoll readiness during reuseport migration
tcp: call sk_data_ready() after listener migration
vhost_net: fix sleeping with preempt-disabled in vhost_net_busy_poll()
ipv6: Cap TLV scan in ip6_tnl_parse_tlv_enc_lim
tipc: fix double-free in tipc_buf_append()
llc: Return -EINPROGRESS from llc_ui_connect()
ipv4: icmp: validate reply type before using icmp_pointers
selftests/net: packetdrill: cover RFC 5961 5.2 challenge ACK on both edges
...
When inet_csk_listen_stop() migrates an established child socket from
a closing listener to another socket in the same SO_REUSEPORT group,
the target listener gets a new accept-queue entry via
inet_csk_reqsk_queue_add(), but that path never notifies the target
listener's waiters. A nonblocking accept() still works because it
checks the queue directly, but poll()/epoll_wait() waiters and
blocking accept() callers can also remain asleep indefinitely.
Call READ_ONCE(nsk->sk_data_ready)(nsk) after a successful migration
in inet_csk_listen_stop().
However, after inet_csk_reqsk_queue_add() succeeds, the ref acquired
in reuseport_migrate_sock() is effectively transferred to
nreq->rsk_listener. Another CPU can then dequeue nreq via accept()
or listener shutdown, hit reqsk_put(), and drop that listener ref.
Since listeners are SOCK_RCU_FREE, wrap the post-queue_add()
dereferences of nsk in rcu_read_lock()/rcu_read_unlock(), which also
covers the existing sock_net(nsk) access in that path.
The reqsk_timer_handler() path does not need the same changes for two
reasons: half-open requests become readable only after the final ACK,
where tcp_child_process() already wakes the listener; and once nreq is
visible via inet_ehash_insert(), the success path no longer touches
nsk directly.
Fixes: 54b92e8419 ("tcp: Migrate TCP_ESTABLISHED/TCP_SYN_RECV sockets in accept queues.")
Cc: stable@vger.kernel.org
Suggested-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Signed-off-by: Zhenzhong Wu <jt26wzz@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260422024554.130346-2-jt26wzz@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
