linux-stable.git/net/core, branch v6.12.95

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

2026-07-04T11:43:32+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

2026-07-04T11:43:32+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: Drop the lock in skb_may_tx_timestamp()

2026-07-04T11:43:24+00:00

[ Upstream commit 983512f3a87fd8dc4c94dfa6b596b6e57df5aad7 ]

skb_may_tx_timestamp() may acquire sock::sk_callback_lock. The lock must
not be taken in IRQ context, only softirq is okay. A few drivers receive
the timestamp via a dedicated interrupt and complete the TX timestamp
from that handler. This will lead to a deadlock if the lock is already
write-locked on the same CPU.

Taking the lock can be avoided. The socket (pointed by the skb) will
remain valid until the skb is released. The ->sk_socket and ->file
member will be set to NULL once the user closes the socket which may
happen before the timestamp arrives.
If we happen to observe the pointer while the socket is closing but
before the pointer is set to NULL then we may use it because both
pointer (and the file's cred member) are RCU freed.

Drop the lock. Use READ_ONCE() to obtain the individual pointer. Add a
matching WRITE_ONCE() where the pointer are cleared.

Link: https://lore.kernel.org/all/20260205145104.iWinkXHv@linutronix.de
Fixes: b245be1f4db1a ("net-timestamp: no-payload only sysctl")
Signed-off-by: Sebastian Andrzej Siewior 
Reviewed-by: Willem de Bruijn 
Reviewed-by: Jason Xing 
Reviewed-by: Eric Dumazet 
Link: https://patch.msgid.link/20260220183858.N4ERjFW6@linutronix.de
Signed-off-by: Paolo Abeni 
[adapted sk_set_socket() in include/net/sock.h to fix the conflict  from
 not having commit 5d6b58c932ec ("net: lockless sock_i_ino()") and the
 additional previous changes required by it.
 It comes down to just now having the lines of
    if (sock) {
            WRITE_ONCE(sk->sk_uid, SOCK_INODE(sock)->i_uid);
            WRITE_ONCE(sk->sk_ino, SOCK_INODE(sock)->i_ino);
    }
 below the changed line.
 I've tested this on a device running an nfs-root and did some
 additional network stress-testing.]
Signed-off-by: Heiko Stuebner 
Signed-off-by: Sasha Levin

tcp: secure_seq: add back ports to TS offset

2026-06-19T11:42:39+00:00

[ Upstream commit 165573e41f2f66ef98940cf65f838b2cb575d9d1 ]

This reverts 28ee1b746f49 ("secure_seq: downgrade to per-host timestamp offsets")

tcp_tw_recycle went away in 2017.

Zhouyan Deng reported off-path TCP source port leakage via
SYN cookie side-channel that can be fixed in multiple ways.

One of them is to bring back TCP ports in TS offset randomization.

As a bonus, we perform a single siphash() computation
to provide both an ISN and a TS offset.

Fixes: 28ee1b746f49 ("secure_seq: downgrade to per-host timestamp offsets")
Reported-by: Zhouyan Deng 
Signed-off-by: Eric Dumazet 
Reviewed-by: Kuniyuki Iwashima 
Acked-by: Florian Westphal 
Link: https://patch.msgid.link/20260302205527.1982836-1-edumazet@google.com
Signed-off-by: Jakub Kicinski 
(cherry picked from commit 165573e41f2f66ef98940cf65f838b2cb575d9d1)
[kept the DCCP functions in the header, as DCCP was not retired yet
 in 6.12]
Signed-off-by: Heiko Stuebner 
Signed-off-by: Greg Kroah-Hartman

tcp: use EXPORT_IPV6_MOD[_GPL]()

2026-06-19T11:42:39+00:00

[ Upstream commit 6dc4c2526f6d11f36c4e26d0231b345eabab584c ]

Use EXPORT_IPV6_MOD[_GPL]() for symbols that don't need
to be exported unless CONFIG_IPV6=m

tcp_hashinfo and tcp_openreq_init_rwin() are no longer
used from any module anyway.

Signed-off-by: Eric Dumazet 
Reviewed-by: Kuniyuki Iwashima 
Reviewed-by: Mateusz Polchlopek 
Link: https://patch.msgid.link/20250212132418.1524422-4-edumazet@google.com
Signed-off-by: Jakub Kicinski 
(cherry picked from commit 6dc4c2526f6d11f36c4e26d0231b345eabab584c)
[needed as dependency for tcp: secure_seq: add back ports to TS offset]
Signed-off-by: Heiko Stuebner 
Signed-off-by: Greg Kroah-Hartman

net: guard timestamp cmsgs to real error queue skbs

2026-06-19T11:42:25+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()

2026-06-19T11:42:24+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()

2026-06-19T11:42:23+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

2026-06-19T11:42:23+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.

2026-06-19T11:42:19+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