linux-stable.git/net/core, branch v6.18.38

net: ip_gre: require CAP_NET_ADMIN in the device netns for changelink

2026-07-04T11:44:17+00:00

commit 8165f7ff57d9667d2bb477ef6af83ede7fed4ad7 upstream.

A tunnel changelink() operates on at most two netns, dev_net(dev) and
the tunnel link netns t->net. They differ once the device is created in
or moved to a netns other than the one the request runs in. The rtnl
changelink path checks CAP_NET_ADMIN only against dev_net(dev), so a
caller privileged there but not in t->net can rewrite a tunnel that
lives in t->net.

Add rtnl_dev_link_net_capable() next to rtnl_get_net_ns_capable() in
net/core/rtnetlink.c. It requires CAP_NET_ADMIN in the link netns and is
skipped when the link netns is dev_net(dev), where the rtnl path already
checked it. The other patches in this series use the same helper.

Gate ipgre_changelink() and erspan_changelink() with it, at the top of
the op before any attribute is parsed, because the parsers update live
tunnel fields first. ipgre_netlink_parms() sets t->collect_md before
ip_tunnel_changelink() runs.

Commit 8b484efd5cb4 ("ip6: vti: Use ip6_tnl.net in
vti6_siocdevprivate().") added the same check on the ioctl path. This
adds it on RTM_NEWLINK.

Reported-by: Xiao Liang 
Closes: https://lore.kernel.org/netdev/CABAhCOSzP1vaThGV35_VnsRCb=87_CPjPVsTHbq905k8A+BuUg@mail.gmail.com/
Fixes: b57708add314 ("gre: add x-netns support")
Cc: stable@vger.kernel.org
Signed-off-by: Maoyi Xie 
Reviewed-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20260612085941.3158249-2-maoyixie.tju@gmail.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

net: skmsg: preserve sg.copy across SG transforms

2026-07-04T11:44:17+00:00

commit 406e8a651a7b854c41fecd5117bb282b3a6c2c6b upstream.

The sk_msg sg.copy bitmap is part of the scatterlist entry ownership
state. A set bit tells sk_msg_compute_data_pointers() not to expose the
entry through writable BPF ctx->data. This protects entries backed by
pages that are not private to the sk_msg, such as splice-backed file
page-cache pages.

Several sk_msg transform paths move, copy, split, or compact
msg->sg.data[] entries without moving the matching sg.copy bit. This can
make an externally backed entry arrive at a new slot with a clear copy
bit. A later SK_MSG verdict can then expose sg_virt(sge) as writable
ctx->data and BPF stores can modify the original page cache.

Keep sg.copy synchronized with sg.data[] whenever entries are
transferred, shifted, split, or copied into a new sk_msg. Clear the bit
when an entry is replaced by a newly allocated private page or freed.
This covers the BPF pull/push/pop helpers, sk_msg_shift_left/right(),
sk_msg_xfer(), and tls_split_open_record(), including the partial tail
entry created during TLS open-record splitting.

Fixes: d3b18ad31f93 ("tls: add bpf support to sk_msg handling")
Cc: stable@vger.kernel.org
Reported-by: Yiming Qian 
Reported-by: Keenan Dong 
Signed-off-by: Yiming Qian 
Link: https://patch.msgid.link/20260610062137.49075-1-yimingqian591@gmail.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

net: net_failover: Fix the deadlock in slave register

2026-06-27T10:06:49+00:00

commit b84c5632c7b31f8910167075a8128cfb9e50fcfe upstream.

There is netdev_lock_ops() before the NETDEV_REGISTER notifier
in register_netdevice(), so use the non-locking functions
in net_failover_slave_register().
failover_slave_register() in failover_existing_slave_register() adds lock
and unlock ops too.

Call Trace:
 
 __schedule+0x30d/0x7a0
 schedule+0x27/0x90
 schedule_preempt_disabled+0x15/0x30
 __mutex_lock.constprop.0+0x538/0x9e0
 __mutex_lock_slowpath+0x13/0x20
 mutex_lock+0x3b/0x50
 dev_set_mtu+0x40/0xe0
 net_failover_slave_register+0x24/0x280
 failover_slave_register+0x103/0x1b0
 failover_event+0x15e/0x210
 ? dropmon_net_event+0xac/0xe0
 notifier_call_chain+0x5e/0xe0
 raw_notifier_call_chain+0x16/0x30
 call_netdevice_notifiers_info+0x52/0xa0
 register_netdevice+0x5f4/0x7c0
 register_netdev+0x1e/0x40
 _mlx5e_probe+0xe2/0x370 [mlx5_core]
 mlx5e_probe+0x59/0x70 [mlx5_core]
 ? __pfx_mlx5e_probe+0x10/0x10 [mlx5_core]

Fixes: 4c975fd70002 ("net: hold instance lock during NETDEV_REGISTER/UP")
Signed-off-by: Faicker Mo 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

net: export netif_open for self_test usage

2026-06-27T10:06:49+00:00

commit 3fdd33697c2be9184668c89ba4f24a5ecbc8ec51 upstream.

dev_open() already is exported, but drivers which use the netdev
instance lock need to use netif_open() instead. netif_close() is
also already exported [1] so this completes the pairing.

This export is required for the following fbnic self tests to
avoid calling ndo_stop() and ndo_open() in favor of the
more appropriate netif_open() and netif_close() that notifies
any listeners that the interface went down to test and is now
coming back up.

Link: https://patch.msgid.link/20250309215851.2003708-1-sdf@fomichev.me [1]
Signed-off-by: Mike Marciniszyn (Meta) 
Link: https://patch.msgid.link/20260307105847.1438-2-mike.marciniszyn@gmail.com
Signed-off-by: Paolo Abeni 
Signed-off-by: Greg Kroah-Hartman

net: guard timestamp cmsgs to real error queue skbs

2026-06-19T11:43:59+00:00

[ Upstream commit 1ee90b77b727df903033db873c75caac5c27ec98 ]

skb_is_err_queue() treats PACKET_OUTGOING as the sole marker for an skb
from sk_error_queue. That assumption is not true for AF_PACKET sockets:
outgoing packet taps are also delivered to packet sockets with
skb->pkt_type == PACKET_OUTGOING, but their skb->cb is owned by AF_PACKET
instead of struct sock_exterr_skb.

If such an skb is received with timestamping enabled, the generic
timestamp cmsg path can read AF_PACKET control-buffer state as
sock_exterr_skb::opt_stats. With SO_RXQ_OVFL enabled, the packet drop
counter overlaps opt_stats. An odd drop count makes the path emit
SCM_TIMESTAMPING_OPT_STATS with skb->len and skb->data. For non-linear
skbs this copies past the linear head and can trigger hardened usercopy or
disclose adjacent heap contents.

Keep skb_is_err_queue() local to net/socket.c, but make it verify that
the PACKET_OUTGOING marker is paired with the sock_rmem_free destructor
installed by sock_queue_err_skb(). AF_PACKET receive skbs use normal
receive ownership and no longer pass as error-queue skbs, while legitimate
sk_error_queue entries keep the PACKET_OUTGOING marker and sock_rmem_free
ownership.

Fixes: 8605330aac5a ("tcp: fix SCM_TIMESTAMPING_OPT_STATS for normal skbs")
Signed-off-by: Kyle Zeng 
Reviewed-by: Kuniyuki Iwashima 
Reviewed-by: Willem de Bruijn 
Link: https://patch.msgid.link/20260607021819.49698-1-kylebot@openai.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

netdev: fix double-free in netdev_nl_bind_rx_doit()

2026-06-19T11:43:58+00:00

[ Upstream commit c849de7d8757a7af801fc4a4058f71d481d367f2 ]

Sashiko flags that genlmsg_reply() always consumes the skb.
The error path calls nlmsg_free(rsp) so we can't jump directly
to it. Let's not unbind, just propagate the error to the user.
This is the typical way of handling genlmsg_reply() failures.
They shouldn't happen unless user does something silly like
calling the kernel with an already-full rcvbuf.

Reported-by: Sashiko 
Fixes: 170aafe35cb9 ("netdev: support binding dma-buf to netdevice")
Reviewed-by: Bobby Eshleman 
Acked-by: Daniel Borkmann 
Reviewed-by: Nikolay Aleksandrov 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

net: add pskb_may_pull() to skb_gro_receive_list()

2026-06-19T11:43:58+00:00

[ Upstream commit f2bb3434544454099a5b6dec213567267b05d79d ]

skb_gro_receive_list() calls skb_pull(skb, skb_gro_offset(skb)) without
first ensuring the data is in the linear area via pskb_may_pull(). When
the skb arrives via napi_gro_frags(), skb_headlen can be 0 (all data in
page fragments) while skb_gro_offset is non-zero (after IP+TCP header
parsing). The skb_pull() then decrements skb->len by skb_gro_offset
but skb->data_len stays unchanged, hitting BUG_ON(skb->len < skb->data_len)
in __skb_pull().

The UDP fraglist GRO path already contains this guard at
udp_offload.c:749. Adding it to skb_gro_receive_list() itself provides
centralized protection for all callers (TCP, UDP, and any future
protocols), and ensures the precondition of skb_pull() is satisfied
before it is called.

On pskb_may_pull() failure, set NAPI_GRO_CB(skb)->flush = 1 so the
skb is not held as a new GRO head and is instead delivered through the
normal receive path, matching the UDP handling.

Fixes: 8d95dc474f85 ("net: add code for TCP fraglist GRO")
Reported-by: HanQuan 
Reported-by: MingXuan 
Signed-off-by: HanQuan 
Reviewed-by: Eric Dumazet 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

tcp: restrict SO_ATTACH_FILTER to priv users

2026-06-19T11:43:58+00:00

[ Upstream commit 5d39580f68e6ddeedd15e587282207489dfb3da2 ]

This patch restricts the use of SO_ATTACH_FILTER (cBPF) on TCP sockets
to users with CAP_NET_ADMIN capability.

This blocks potential side-channel attack where an unprivileged application
attaches a filter to leak TCP sequence/acknowledgment numbers.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet 
Reported-by: Tamir Shahar 
Reported-by: Amit Klein 
Cc: Willem de Bruijn 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: Andrii Nakryiko 
Cc: Martin KaFai Lau 
Cc: Eduard Zingerman 
Cc: Kumar Kartikeya Dwivedi 
Cc: Song Liu 
Cc: Yonghong Song 
Cc: Jiri Olsa 
Cc: John Fastabend 
Cc: Stanislav Fomichev 
Acked-by: Daniel Borkmann 
Reviewed-by: Willem de Bruijn 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

net: Annotate sk->sk_write_space() for UDP SOCKMAP.

2026-06-19T11:43:53+00:00

[ Upstream commit b748765019fe9e9234660327090fc1a9665cdbdd ]

UDP TX skb->destructor() is sock_wfree(), and UDP holds lock_sock()
only for UDP_CORK / MSG_MORE sendmsg().

Otherwise, sk->sk_write_space() may be read locklessly while SOCKMAP
rewrites sk->sk_write_space().

Let's use WRITE_ONCE() and READ_ONCE() for sk->sk_write_space().

Note that the write side is annotated by commit 2ef2b20cf4e0
("net: annotate data-races around sk->sk_{data_ready,write_space}").

Fixes: 7b98cd42b049 ("bpf: sockmap: Add UDP support")
Signed-off-by: Kuniyuki Iwashima 
Reviewed-by: Jakub Sitnicki 
Link: https://patch.msgid.link/20260529193941.3897256-1-kuniyu@google.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

bpf: Free reuseport cBPF prog after RCU grace period.

2026-06-19T11:43:50+00:00

[ Upstream commit 18fc650ccd7fe3376eca89203668cfb8268f60df ]

Eulgyu Kim reported the splat below with a repro. [0]

The repro sets up a UDP reuseport group with a cBPF prog and
replaces it with a new one while another thread is sending
a UDP packet to the group.

The reuseport prog is freed by sk_reuseport_prog_free().
bpf_prog_put() is called for "e"BPF prog to destruct through
multiple stages while cBPF prog is freed immediately by
bpf_release_orig_filter() and bpf_prog_free().

If a reuseport prog is detached from the setsockopt() path
(reuseport_attach_prog() or reuseport_detach_prog()),
sk_reuseport_prog_free() is called without waiting for RCU
readers to complete, resulting in various bugs.

Let's defer freeing the reuseport cBPF prog after one RCU
grace period.

Note "e"BPF prog is safe as is unless the fast path starts
to touch fields destroyed in bpf_prog_put_deferred() and
__bpf_prog_put_noref().

[0]:
BUG: KASAN: vmalloc-out-of-bounds in reuseport_select_sock+0xedc/0x1220 net/core/sock_reuseport.c:596
Read of size 4 at addr ffffc9000051e004 by task slowme/10208
CPU: 6 UID: 1000 PID: 10208 Comm: slowme Not tainted 7.0.0-geb7ac95ff75e #32 PREEMPT(full)
Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 reuseport_select_sock+0xedc/0x1220 net/core/sock_reuseport.c:596
 udp4_lib_lookup2+0x3bc/0x950 net/ipv4/udp.c:495
 __udp4_lib_lookup+0x768/0xe20 net/ipv4/udp.c:723
 __udp4_lib_lookup_skb+0x297/0x390 net/ipv4/udp.c:752
 __udp4_lib_rcv+0x1312/0x2620 net/ipv4/udp.c:2752
 ip_protocol_deliver_rcu+0x282/0x440 net/ipv4/ip_input.c:207
 ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:241
 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318
 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318
 __netif_receive_skb_one_core net/core/dev.c:6181 [inline]
 __netif_receive_skb net/core/dev.c:6294 [inline]
 process_backlog+0xaa4/0x1960 net/core/dev.c:6645
 __napi_poll+0xae/0x340 net/core/dev.c:7709
 napi_poll net/core/dev.c:7772 [inline]
 net_rx_action+0x5d7/0xf50 net/core/dev.c:7929
 handle_softirqs+0x22b/0x870 kernel/softirq.c:622
 do_softirq+0x76/0xd0 kernel/softirq.c:523
 
 
 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:924 [inline]
 __dev_queue_xmit+0x1dd7/0x3710 net/core/dev.c:4890
 neigh_output include/net/neighbour.h:556 [inline]
 ip_finish_output2+0xca9/0x1070 net/ipv4/ip_output.c:237
 NF_HOOK_COND include/linux/netfilter.h:307 [inline]
 ip_output+0x29f/0x450 net/ipv4/ip_output.c:438
 ip_send_skb+0x45/0xc0 net/ipv4/ip_output.c:1508
 udp_send_skb+0xb04/0x1510 net/ipv4/udp.c:1195
 udp_sendmsg+0x1a71/0x2350 net/ipv4/udp.c:1485
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 __sys_sendto+0x554/0x680 net/socket.c:2206
 __do_sys_sendto net/socket.c:2213 [inline]
 __se_sys_sendto net/socket.c:2209 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2209
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x160/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x415a2d
Code: b3 66 2e 0f 1f 84 00 00 00 00 00 66 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6bc31e41e8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f6bc31e4cdc RCX: 0000000000415a2d
RDX: 0000000000000001 RSI: 00007f6bc31e421f RDI: 0000000000000003
RBP: 00007f6bc31e4240 R08: 00007f6bc31e4220 R09: 0000000000000010
R10: 0000000000000000 R11: 0000000000000212 R12: 00007f6bc31e46c0
R13: ffffffffffffffb8 R14: 0000000000000000 R15: 00007ffc9b0d70b0
 

Fixes: 538950a1b752 ("soreuseport: setsockopt SO_ATTACH_REUSEPORT_[CE]BPF")
Reported-by: Eulgyu Kim 
Reported-by: Taeyang Lee <0wn@theori.io>
Signed-off-by: Kuniyuki Iwashima 
Signed-off-by: Daniel Borkmann 
Acked-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20260426012647.3233119-1-kuniyu@google.com
Signed-off-by: Sasha Levin