linux-stable.git/net/ipv6, branch linux-6.16.y Linux kernel stable tree net: remove sock_i_uid() 2025-09-09T17:02:26+00:00 Eric Dumazet edumazet@google.com 2025-06-20T13:30:01+00:00 242124e3e3a7f958e805da5c991307026188b8c5 [ Upstream commit c51da3f7a161c6822232be832abdffe47eb55b4c ] Difference between sock_i_uid() and sk_uid() is that after sock_orphan(), sock_i_uid() returns GLOBAL_ROOT_UID while sk_uid() returns the last cached sk->sk_uid value. None of sock_i_uid() callers care about this. Use sk_uid() which is much faster and inlined. Note that diag/dump users are calling sock_i_ino() and can not see the full benefit yet. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Lorenzo Colitti <lorenzo@google.com> Reviewed-by: Maciej Żenczykowski <maze@google.com> Link: https://patch.msgid.link/20250620133001.4090592-3-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Stable-dep-of: 5d6b58c932ec ("net: lockless sock_i_ino()") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit c51da3f7a161c6822232be832abdffe47eb55b4c ]

Difference between sock_i_uid() and sk_uid() is that
after sock_orphan(), sock_i_uid() returns GLOBAL_ROOT_UID
while sk_uid() returns the last cached sk->sk_uid value.

None of sock_i_uid() callers care about this.

Use sk_uid() which is much faster and inlined.

Note that diag/dump users are calling sock_i_ino() and
can not see the full benefit yet.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Reviewed-by: Maciej Żenczykowski <maze@google.com>
Link: https://patch.msgid.link/20250620133001.4090592-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: 5d6b58c932ec ("net: lockless sock_i_ino()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
net/tcp: Fix socket memory leak in TCP-AO failure handling for IPv6 2025-09-09T17:02:24+00:00 Christoph Paasch cpaasch@openai.com 2025-08-30T22:55:38+00:00 3d2b356d994a8801acb397cafd28b13672c37ab5 [ Upstream commit fa390321aba0a54d0f7ae95ee4ecde1358bb9234 ] When tcp_ao_copy_all_matching() fails in tcp_v6_syn_recv_sock() it just exits the function. This ends up causing a memory-leak: unreferenced object 0xffff0000281a8200 (size 2496): comm "softirq", pid 0, jiffies 4295174684 hex dump (first 32 bytes): 7f 00 00 06 7f 00 00 06 00 00 00 00 cb a8 88 13 ................ 0a 00 03 61 00 00 00 00 00 00 00 00 00 00 00 00 ...a............ backtrace (crc 5ebdbe15): kmemleak_alloc+0x44/0xe0 kmem_cache_alloc_noprof+0x248/0x470 sk_prot_alloc+0x48/0x120 sk_clone_lock+0x38/0x3b0 inet_csk_clone_lock+0x34/0x150 tcp_create_openreq_child+0x3c/0x4a8 tcp_v6_syn_recv_sock+0x1c0/0x620 tcp_check_req+0x588/0x790 tcp_v6_rcv+0x5d0/0xc18 ip6_protocol_deliver_rcu+0x2d8/0x4c0 ip6_input_finish+0x74/0x148 ip6_input+0x50/0x118 ip6_sublist_rcv+0x2fc/0x3b0 ipv6_list_rcv+0x114/0x170 __netif_receive_skb_list_core+0x16c/0x200 netif_receive_skb_list_internal+0x1f0/0x2d0 This is because in tcp_v6_syn_recv_sock (and the IPv4 counterpart), when exiting upon error, inet_csk_prepare_forced_close() and tcp_done() need to be called. They make sure the newsk will end up being correctly free'd. tcp_v4_syn_recv_sock() makes this very clear by having the put_and_exit label that takes care of things. So, this patch here makes sure tcp_v4_syn_recv_sock and tcp_v6_syn_recv_sock have similar error-handling and thus fixes the leak for TCP-AO. Fixes: 06b22ef29591 ("net/tcp: Wire TCP-AO to request sockets") Signed-off-by: Christoph Paasch <cpaasch@openai.com> Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com> Link: https://patch.msgid.link/20250830-tcpao_leak-v1-1-e5878c2c3173@openai.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit fa390321aba0a54d0f7ae95ee4ecde1358bb9234 ]

When tcp_ao_copy_all_matching() fails in tcp_v6_syn_recv_sock() it just
exits the function. This ends up causing a memory-leak:

unreferenced object 0xffff0000281a8200 (size 2496):
  comm "softirq", pid 0, jiffies 4295174684
  hex dump (first 32 bytes):
    7f 00 00 06 7f 00 00 06 00 00 00 00 cb a8 88 13  ................
    0a 00 03 61 00 00 00 00 00 00 00 00 00 00 00 00  ...a............
  backtrace (crc 5ebdbe15):
    kmemleak_alloc+0x44/0xe0
    kmem_cache_alloc_noprof+0x248/0x470
    sk_prot_alloc+0x48/0x120
    sk_clone_lock+0x38/0x3b0
    inet_csk_clone_lock+0x34/0x150
    tcp_create_openreq_child+0x3c/0x4a8
    tcp_v6_syn_recv_sock+0x1c0/0x620
    tcp_check_req+0x588/0x790
    tcp_v6_rcv+0x5d0/0xc18
    ip6_protocol_deliver_rcu+0x2d8/0x4c0
    ip6_input_finish+0x74/0x148
    ip6_input+0x50/0x118
    ip6_sublist_rcv+0x2fc/0x3b0
    ipv6_list_rcv+0x114/0x170
    __netif_receive_skb_list_core+0x16c/0x200
    netif_receive_skb_list_internal+0x1f0/0x2d0

This is because in tcp_v6_syn_recv_sock (and the IPv4 counterpart), when
exiting upon error, inet_csk_prepare_forced_close() and tcp_done() need
to be called. They make sure the newsk will end up being correctly
free'd.

tcp_v4_syn_recv_sock() makes this very clear by having the put_and_exit
label that takes care of things. So, this patch here makes sure
tcp_v4_syn_recv_sock and tcp_v6_syn_recv_sock have similar
error-handling and thus fixes the leak for TCP-AO.

Fixes: 06b22ef29591 ("net/tcp: Wire TCP-AO to request sockets")
Signed-off-by: Christoph Paasch <cpaasch@openai.com>
Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Link: https://patch.msgid.link/20250830-tcpao_leak-v1-1-e5878c2c3173@openai.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
icmp: fix icmp_ndo_send address translation for reply direction 2025-09-09T17:02:22+00:00 Fabian Bläse fabian@blaese.de 2025-08-28T09:14:35+00:00 c3e20abfd33d8bed59acdd105024b2d90e1df5d9 [ Upstream commit c6dd1aa2cbb72b33e0569f3e71d95792beab5042 ] The icmp_ndo_send function was originally introduced to ensure proper rate limiting when icmp_send is called by a network device driver, where the packet's source address may have already been transformed by SNAT. However, the original implementation only considers the IP_CT_DIR_ORIGINAL direction for SNAT and always replaced the packet's source address with that of the original-direction tuple. This causes two problems: 1. For SNAT: Reply-direction packets were incorrectly translated using the source address of the CT original direction, even though no translation is required. 2. For DNAT: Reply-direction packets were not handled at all. In DNAT, the original direction's destination is translated. Therefore, in the reply direction the source address must be set to the reply-direction source, so rate limiting works as intended. Fix this by using the connection direction to select the correct tuple for source address translation, and adjust the pre-checks to handle reply-direction packets in case of DNAT. Additionally, wrap the `ct->status` access in READ_ONCE(). This avoids possible KCSAN reports about concurrent updates to `ct->status`. Fixes: 0b41713b6066 ("icmp: introduce helper for nat'd source address in network device context") Signed-off-by: Fabian Bläse <fabian@blaese.de> Cc: Jason A. Donenfeld <Jason@zx2c4.com> Reviewed-by: Florian Westphal <fw@strlen.de> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit c6dd1aa2cbb72b33e0569f3e71d95792beab5042 ]

The icmp_ndo_send function was originally introduced to ensure proper
rate limiting when icmp_send is called by a network device driver,
where the packet's source address may have already been transformed
by SNAT.

However, the original implementation only considers the
IP_CT_DIR_ORIGINAL direction for SNAT and always replaced the packet's
source address with that of the original-direction tuple. This causes
two problems:

1. For SNAT:
   Reply-direction packets were incorrectly translated using the source
   address of the CT original direction, even though no translation is
   required.

2. For DNAT:
   Reply-direction packets were not handled at all. In DNAT, the original
   direction's destination is translated. Therefore, in the reply
   direction the source address must be set to the reply-direction
   source, so rate limiting works as intended.

Fix this by using the connection direction to select the correct tuple
for source address translation, and adjust the pre-checks to handle
reply-direction packets in case of DNAT.

Additionally, wrap the `ct->status` access in READ_ONCE(). This avoids
possible KCSAN reports about concurrent updates to `ct->status`.

Fixes: 0b41713b6066 ("icmp: introduce helper for nat'd source address in network device context")
Signed-off-by: Fabian Bläse <fabian@blaese.de>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
netfilter: nf_reject: don't leak dst refcount for loopback packets 2025-08-28T14:34:51+00:00 Florian Westphal fw@strlen.de 2025-08-20T12:37:07+00:00 b32e1590a8d22cf7d7f965e46d5576051acf8e42 [ Upstream commit 91a79b792204313153e1bdbbe5acbfc28903b3a5 ] recent patches to add a WARN() when replacing skb dst entry found an old bug: WARNING: include/linux/skbuff.h:1165 skb_dst_check_unset include/linux/skbuff.h:1164 [inline] WARNING: include/linux/skbuff.h:1165 skb_dst_set include/linux/skbuff.h:1210 [inline] WARNING: include/linux/skbuff.h:1165 nf_reject_fill_skb_dst+0x2a4/0x330 net/ipv4/netfilter/nf_reject_ipv4.c:234 [..] Call Trace: nf_send_unreach+0x17b/0x6e0 net/ipv4/netfilter/nf_reject_ipv4.c:325 nft_reject_inet_eval+0x4bc/0x690 net/netfilter/nft_reject_inet.c:27 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] .. This is because blamed commit forgot about loopback packets. Such packets already have a dst_entry attached, even at PRE_ROUTING stage. Instead of checking hook just check if the skb already has a route attached to it. Fixes: f53b9b0bdc59 ("netfilter: introduce support for reject at prerouting stage") Signed-off-by: Florian Westphal <fw@strlen.de> Link: https://patch.msgid.link/20250820123707.10671-1-fw@strlen.de Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 91a79b792204313153e1bdbbe5acbfc28903b3a5 ]

recent patches to add a WARN() when replacing skb dst entry found an
old bug:

WARNING: include/linux/skbuff.h:1165 skb_dst_check_unset include/linux/skbuff.h:1164 [inline]
WARNING: include/linux/skbuff.h:1165 skb_dst_set include/linux/skbuff.h:1210 [inline]
WARNING: include/linux/skbuff.h:1165 nf_reject_fill_skb_dst+0x2a4/0x330 net/ipv4/netfilter/nf_reject_ipv4.c:234
[..]
Call Trace:
 nf_send_unreach+0x17b/0x6e0 net/ipv4/netfilter/nf_reject_ipv4.c:325
 nft_reject_inet_eval+0x4bc/0x690 net/netfilter/nft_reject_inet.c:27
 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
 ..

This is because blamed commit forgot about loopback packets.
Such packets already have a dst_entry attached, even at PRE_ROUTING stage.

Instead of checking hook just check if the skb already has a route
attached to it.

Fixes: f53b9b0bdc59 ("netfilter: introduce support for reject at prerouting stage")
Signed-off-by: Florian Westphal <fw@strlen.de>
Link: https://patch.msgid.link/20250820123707.10671-1-fw@strlen.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
ipv6: sr: validate HMAC algorithm ID in seg6_hmac_info_add 2025-08-28T14:34:47+00:00 Minhong He heminhong@kylinos.cn 2025-08-15T06:38:45+00:00 60f6f39cd57be67e91749e74f224c5b0254a3391 [ Upstream commit 84967deee9d9870b15bc4c3acb50f1d401807902 ] The seg6_genl_sethmac() directly uses the algorithm ID provided by the userspace without verifying whether it is an HMAC algorithm supported by the system. If an unsupported HMAC algorithm ID is configured, packets using SRv6 HMAC will be dropped during encapsulation or decapsulation. Fixes: 4f4853dc1c9c ("ipv6: sr: implement API to control SR HMAC structure") Signed-off-by: Minhong He <heminhong@kylinos.cn> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20250815063845.85426-1-heminhong@kylinos.cn Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 84967deee9d9870b15bc4c3acb50f1d401807902 ]

The seg6_genl_sethmac() directly uses the algorithm ID provided by the
userspace without verifying whether it is an HMAC algorithm supported
by the system.
If an unsupported HMAC algorithm ID is configured, packets using SRv6 HMAC
will be dropped during encapsulation or decapsulation.

Fixes: 4f4853dc1c9c ("ipv6: sr: implement API to control SR HMAC structure")
Signed-off-by: Minhong He <heminhong@kylinos.cn>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250815063845.85426-1-heminhong@kylinos.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
ipv6: sr: Fix MAC comparison to be constant-time 2025-08-28T14:34:32+00:00 Eric Biggers ebiggers@kernel.org 2025-08-18T20:27:24+00:00 f7878d47560d61e3f370aca3cebb8f42a55b990a commit a458b2902115b26a25d67393b12ddd57d1216aaa upstream. To prevent timing attacks, MACs need to be compared in constant time. Use the appropriate helper function for this. Fixes: bf355b8d2c30 ("ipv6: sr: add core files for SR HMAC support") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@kernel.org> Reviewed-by: Andrea Mayer <andrea.mayer@uniroma2.it> Link: https://patch.msgid.link/20250818202724.15713-1-ebiggers@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit a458b2902115b26a25d67393b12ddd57d1216aaa upstream.

To prevent timing attacks, MACs need to be compared in constant time.
Use the appropriate helper function for this.

Fixes: bf355b8d2c30 ("ipv6: sr: add core files for SR HMAC support")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Reviewed-by: Andrea Mayer <andrea.mayer@uniroma2.it>
Link: https://patch.msgid.link/20250818202724.15713-1-ebiggers@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ipv6: mcast: Check inet6_dev->dead under idev->mc_lock in __ipv6_dev_mc_inc(). 2025-08-20T16:41:11+00:00 Kuniyuki Iwashima kuniyu@google.com 2025-07-02T23:01:20+00:00 f8aadf19786d672d5d148829e202b642185902aa [ Upstream commit dbd40f318cf2f59759bd170c401adc20ba360a3e ] Since commit 63ed8de4be81 ("mld: add mc_lock for protecting per-interface mld data"), every multicast resource is protected by inet6_dev->mc_lock. RTNL is unnecessary in terms of protection but still needed for synchronisation between addrconf_ifdown() and __ipv6_dev_mc_inc(). Once we removed RTNL, there would be a race below, where we could add a multicast address to a dead inet6_dev. CPU1 CPU2 ==== ==== addrconf_ifdown() __ipv6_dev_mc_inc() if (idev->dead) <-- false dead = true return -ENODEV; ipv6_mc_destroy_dev() / ipv6_mc_down() mutex_lock(&idev->mc_lock) ... mutex_unlock(&idev->mc_lock) mutex_lock(&idev->mc_lock) ... mutex_unlock(&idev->mc_lock) The race window can be easily closed by checking inet6_dev->dead under inet6_dev->mc_lock in __ipv6_dev_mc_inc() as addrconf_ifdown() will acquire it after marking inet6_dev dead. Let's check inet6_dev->dead under mc_lock in __ipv6_dev_mc_inc(). Note that now __ipv6_dev_mc_inc() no longer depends on RTNL and we can remove ASSERT_RTNL() there and the RTNL comment above addrconf_join_solict(). Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250702230210.3115355-4-kuni1840@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit dbd40f318cf2f59759bd170c401adc20ba360a3e ]

Since commit 63ed8de4be81 ("mld: add mc_lock for protecting
per-interface mld data"), every multicast resource is protected
by inet6_dev->mc_lock.

RTNL is unnecessary in terms of protection but still needed for
synchronisation between addrconf_ifdown() and __ipv6_dev_mc_inc().

Once we removed RTNL, there would be a race below, where we could
add a multicast address to a dead inet6_dev.

  CPU1                            CPU2
  ====                            ====
  addrconf_ifdown()               __ipv6_dev_mc_inc()
                                    if (idev->dead) <-- false
    dead = true                       return -ENODEV;
    ipv6_mc_destroy_dev() / ipv6_mc_down()
      mutex_lock(&idev->mc_lock)
      ...
      mutex_unlock(&idev->mc_lock)
                                    mutex_lock(&idev->mc_lock)
                                    ...
                                    mutex_unlock(&idev->mc_lock)

The race window can be easily closed by checking inet6_dev->dead
under inet6_dev->mc_lock in __ipv6_dev_mc_inc() as addrconf_ifdown()
will acquire it after marking inet6_dev dead.

Let's check inet6_dev->dead under mc_lock in __ipv6_dev_mc_inc().

Note that now __ipv6_dev_mc_inc() no longer depends on RTNL and
we can remove ASSERT_RTNL() there and the RTNL comment above
addrconf_join_solict().

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250702230210.3115355-4-kuni1840@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
xfrm: flush all states in xfrm_state_fini 2025-08-20T16:40:50+00:00 Sabrina Dubroca sd@queasysnail.net 2025-08-04T09:05:43+00:00 34a4558b69e6c78d78831fbb0013ef700357aee8 [ Upstream commit 42e42562c9cfcdacf000f1b42284a4fad24f8546 ] While reverting commit f75a2804da39 ("xfrm: destroy xfrm_state synchronously on net exit path"), I incorrectly changed xfrm_state_flush's "proto" argument back to IPSEC_PROTO_ANY. This reverts some of the changes in commit dbb2483b2a46 ("xfrm: clean up xfrm protocol checks"), and leads to some states not being removed when we exit the netns. Pass 0 instead of IPSEC_PROTO_ANY from both xfrm_state_fini xfrm6_tunnel_net_exit, so that xfrm_state_flush deletes all states. Fixes: 2a198bbec691 ("Revert "xfrm: destroy xfrm_state synchronously on net exit path"") Reported-by: syzbot+6641a61fe0e2e89ae8c5@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=6641a61fe0e2e89ae8c5 Tested-by: syzbot+6641a61fe0e2e89ae8c5@syzkaller.appspotmail.com Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Reviewed-by: Simon Horman <horms@kernel.org> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 42e42562c9cfcdacf000f1b42284a4fad24f8546 ]

While reverting commit f75a2804da39 ("xfrm: destroy xfrm_state
synchronously on net exit path"), I incorrectly changed
xfrm_state_flush's "proto" argument back to IPSEC_PROTO_ANY. This
reverts some of the changes in commit dbb2483b2a46 ("xfrm: clean up
xfrm protocol checks"), and leads to some states not being removed
when we exit the netns.

Pass 0 instead of IPSEC_PROTO_ANY from both xfrm_state_fini
xfrm6_tunnel_net_exit, so that xfrm_state_flush deletes all states.

Fixes: 2a198bbec691 ("Revert "xfrm: destroy xfrm_state synchronously on net exit path"")
Reported-by: syzbot+6641a61fe0e2e89ae8c5@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=6641a61fe0e2e89ae8c5
Tested-by: syzbot+6641a61fe0e2e89ae8c5@syzkaller.appspotmail.com
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
ipv6: reject malicious packets in ipv6_gso_segment() 2025-08-15T14:39:25+00:00 Eric Dumazet edumazet@google.com 2025-07-30T13:17:38+00:00 ee851768e4b8371ce151fd446d24bf3ae2d18789 [ Upstream commit d45cf1e7d7180256e17c9ce88e32e8061a7887fe ] syzbot was able to craft a packet with very long IPv6 extension headers leading to an overflow of skb->transport_header. This 16bit field has a limited range. Add skb_reset_transport_header_careful() helper and use it from ipv6_gso_segment() WARNING: CPU: 0 PID: 5871 at ./include/linux/skbuff.h:3032 skb_reset_transport_header include/linux/skbuff.h:3032 [inline] WARNING: CPU: 0 PID: 5871 at ./include/linux/skbuff.h:3032 ipv6_gso_segment+0x15e2/0x21e0 net/ipv6/ip6_offload.c:151 Modules linked in: CPU: 0 UID: 0 PID: 5871 Comm: syz-executor211 Not tainted 6.16.0-rc6-syzkaller-g7abc678e3084 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:skb_reset_transport_header include/linux/skbuff.h:3032 [inline] RIP: 0010:ipv6_gso_segment+0x15e2/0x21e0 net/ipv6/ip6_offload.c:151 Call Trace: <TASK> skb_mac_gso_segment+0x31c/0x640 net/core/gso.c:53 nsh_gso_segment+0x54a/0xe10 net/nsh/nsh.c:110 skb_mac_gso_segment+0x31c/0x640 net/core/gso.c:53 __skb_gso_segment+0x342/0x510 net/core/gso.c:124 skb_gso_segment include/net/gso.h:83 [inline] validate_xmit_skb+0x857/0x11b0 net/core/dev.c:3950 validate_xmit_skb_list+0x84/0x120 net/core/dev.c:4000 sch_direct_xmit+0xd3/0x4b0 net/sched/sch_generic.c:329 __dev_xmit_skb net/core/dev.c:4102 [inline] __dev_queue_xmit+0x17b6/0x3a70 net/core/dev.c:4679 Fixes: d1da932ed4ec ("ipv6: Separate ipv6 offload support") Reported-by: syzbot+af43e647fd835acc02df@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/688a1a05.050a0220.5d226.0008.GAE@google.com/T/#u Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Dawid Osuchowski <dawid.osuchowski@linux.intel.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20250730131738.3385939-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit d45cf1e7d7180256e17c9ce88e32e8061a7887fe ]

syzbot was able to craft a packet with very long IPv6 extension headers
leading to an overflow of skb->transport_header.

This 16bit field has a limited range.

Add skb_reset_transport_header_careful() helper and use it
from ipv6_gso_segment()

WARNING: CPU: 0 PID: 5871 at ./include/linux/skbuff.h:3032 skb_reset_transport_header include/linux/skbuff.h:3032 [inline]
WARNING: CPU: 0 PID: 5871 at ./include/linux/skbuff.h:3032 ipv6_gso_segment+0x15e2/0x21e0 net/ipv6/ip6_offload.c:151
Modules linked in:
CPU: 0 UID: 0 PID: 5871 Comm: syz-executor211 Not tainted 6.16.0-rc6-syzkaller-g7abc678e3084 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
 RIP: 0010:skb_reset_transport_header include/linux/skbuff.h:3032 [inline]
 RIP: 0010:ipv6_gso_segment+0x15e2/0x21e0 net/ipv6/ip6_offload.c:151
Call Trace:
 <TASK>
  skb_mac_gso_segment+0x31c/0x640 net/core/gso.c:53
  nsh_gso_segment+0x54a/0xe10 net/nsh/nsh.c:110
  skb_mac_gso_segment+0x31c/0x640 net/core/gso.c:53
  __skb_gso_segment+0x342/0x510 net/core/gso.c:124
  skb_gso_segment include/net/gso.h:83 [inline]
  validate_xmit_skb+0x857/0x11b0 net/core/dev.c:3950
  validate_xmit_skb_list+0x84/0x120 net/core/dev.c:4000
  sch_direct_xmit+0xd3/0x4b0 net/sched/sch_generic.c:329
  __dev_xmit_skb net/core/dev.c:4102 [inline]
  __dev_queue_xmit+0x17b6/0x3a70 net/core/dev.c:4679

Fixes: d1da932ed4ec ("ipv6: Separate ipv6 offload support")
Reported-by: syzbot+af43e647fd835acc02df@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/688a1a05.050a0220.5d226.0008.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Dawid Osuchowski <dawid.osuchowski@linux.intel.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250730131738.3385939-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
ipv6: annotate data-races around rt->fib6_nsiblings 2025-08-15T14:38:55+00:00 Eric Dumazet edumazet@google.com 2025-07-25T14:07:25+00:00 8ec2c728912a61107aebf8a526f5cbcdea7d3572 [ Upstream commit 31d7d67ba1274f42494256d52e86da80ed09f3cb ] rt->fib6_nsiblings can be read locklessly, add corresponding READ_ONCE() and WRITE_ONCE() annotations. Fixes: 66f5d6ce53e6 ("ipv6: replace rwlock with rcu and spinlock in fib6_table") Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250725140725.3626540-5-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 31d7d67ba1274f42494256d52e86da80ed09f3cb ]

rt->fib6_nsiblings can be read locklessly, add corresponding
READ_ONCE() and WRITE_ONCE() annotations.

Fixes: 66f5d6ce53e6 ("ipv6: replace rwlock with rcu and spinlock in fib6_table")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250725140725.3626540-5-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>