kernel/linux.git/net/core/sock.c, branch v7.1.12

net: remove WARN_ON_ONCE() from sk_mc_loop()

2026-08-19T16:20:20+00:00

[ Upstream commit b8a39a09ae4eaae04309e1e38ed6a1101d967496 ] sk_mc_loop() can be called for sockets that are neither AF_INET nor AF_INET6 (e.g. AF_PACKET sockets when sending packets via raw/packet socket over virtual devices such as VRF or ipvlan). In such cases, sk_family is not AF_INET/AF_INET6 and sk_mc_loop() falls through the switch statement and triggers WARN_ON_ONCE(1). Non-INET sockets do not support IP_MULTICAST_LOOP or IPV6_MULTICAST_LOOP options, so loopback should default to true without generating a warning. Fixes: f60e5990d9c1 ("ipv6: protect skb->sk accesses from recursive dereference inside the stack") Reported-by: syzbot+22c3218a6fa219e47321@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/6a72024c.13623e66.bdc14.0019.GAE@google.com/T/#u Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260804152048.2134341-1-edumazet@google.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

net: Call net_enable_timestamp() before failure in sk_clone().

2026-08-03T09:25:32+00:00

[ Upstream commit d50557779257a00162411e3048d82971ff1f644c ] When sk_clone() fails, sk_destruct() is called for the new socket. If the parent socket has SK_FLAGS_TIMESTAMP in sk->sk_flags, net_disable_timestamp() is called for the child socket even though net_enable_timestamp() is not called for it. Let's call net_enable_timestamp() before any failure path in sk_clone(). Fixes: 704da560c0a0 ("tcp: update the netstamp_needed counter when cloning sockets") Reported-by: Sashiko Closes: https://lore.kernel.org/all/20260709032007.9E4D61F000E9@smtp.kernel.org/ Signed-off-by: Kuniyuki Iwashima Reviewed-by: Willem de Bruijn Reviewed-by: Jason Xing Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260709183315.965751-3-kuniyu@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

soreuseport: Clear sk_reuseport_cb before failure in sk_clone().

2026-08-03T09:25:32+00:00

[ Upstream commit 98da8ce87dd561f08fbe44f75865edc5d9b2ba5f ] When sk_clone() fails, sk_destruct() is called for the new socket. If the parent socket has sk->sk_reuseport_cb, the child will call reuseport_detach_sock() for the reuseport group. Let's clear sk->sk_reuseport_cb before any failure path in sk_clone(). Note that this was not a problem before the cited commit because reuseport_detach_sock() did nothing if the socket was not found in the reuseport array. Fixes: 5dc4c4b7d4e8 ("bpf: Introduce BPF_MAP_TYPE_REUSEPORT_SOCKARRAY") Reported-by: Sashiko Closes: https://lore.kernel.org/all/20260709032007.9E4D61F000E9@smtp.kernel.org/ Signed-off-by: Kuniyuki Iwashima Reviewed-by: Willem de Bruijn Reviewed-by: Jason Xing Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260709183315.965751-2-kuniyu@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

bpf: Fix UAF in sock clone early bailouts

2026-08-03T09:25:20+00:00

[ Upstream commit 7cbd0c4cebe4c9f678d15e6b9ba975e1155a107f ] Similar to recent commit 9b51a6155d14 ("bpf,fork: wipe ->bpf_storage before bailouts that access it"), sk_clone() performs an initial shallow copy of the socket field ->sk_bpf_storage via sock_copy() for the cloned socket newsk. If sk_clone() bails out early (e.g. if sk_filter_charge() fails) prior to calling bpf_sk_storage_clone(), newsk->sk_bpf_storage still points to the parent socket's BPF local storage. When newsk is subsequently freed via sk_free(), the deallocation path (__sk_destruct() -> bpf_sk_storage_free()) destroys the parent socket's BPF local storage, leading to a use-after-free (UAF) on the parent socket. Fix this by resetting newsk->sk_bpf_storage to NULL immediately after sock_copy() in sk_clone(), and remove the now redundant initialization from bpf_sk_storage_clone(). Fixes: 6ac99e8f23d4 ("bpf: Introduce bpf sk local storage") Fixes: f12dd75959b0 ("bpf: net: Set sk_bpf_storage back to NULL for cloned sk") Signed-off-by: Matt Bobrowski Signed-off-by: Daniel Borkmann Reviewed-by: Kuniyuki Iwashima Acked-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20260709025316.999913-1-mattbobrowski@google.com Signed-off-by: Sasha Levin

tcp: restrict SO_ATTACH_FILTER to priv users

2026-06-08T22:37:10+00:00

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

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

2026-06-02T18:44:43+00:00

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

tcp: update window_clamp when SO_RCVBUF is set

2026-04-13T13:32:35+00:00

Commit under Fixes moved recomputing the window clamp to tcp_measure_rcv_mss() (when scaling_ratio changes). I suspect it missed the fact that we don't recompute the clamp when rcvbuf is set. Until scaling_ratio changes we are stuck with the old window clamp which may be based on the small initial buffer. scaling_ratio may never change. Inspired by Eric's recent commit d1361840f8c5 ("tcp: fix SO_RCVLOWAT and RCVBUF autotuning") plumb the user action thru to TCP and have it update the clamp. A smaller fix would be to just have tcp_rcvbuf_grow() adjust the clamp even if SOCK_RCVBUF_LOCK is set. But IIUC this is what we were trying to get away from in the first place. Fixes: a2cbb1603943 ("tcp: Update window clamping condition") Signed-off-by: Jakub Kicinski Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20260408001438.129165-1-kuba@kernel.org Signed-off-by: Paolo Abeni

net: change sk_filter_trim_cap() to return a drop_reason by value

2026-04-12T21:30:25+00:00

Current return value can be replaced with the drop_reason, reducing kernel bloat: $ scripts/bloat-o-meter -t vmlinux.old vmlinux.new add/remove: 0/2 grow/shrink: 1/11 up/down: 32/-603 (-571) Function old new delta tcp_v6_rcv 3135 3167 +32 unix_dgram_sendmsg 1731 1726 -5 netlink_unicast 957 945 -12 netlink_dump 1372 1359 -13 sk_filter_trim_cap 882 858 -24 tcp_v4_rcv 3143 3111 -32 __pfx_tcp_filter 32 - -32 netlink_broadcast_filtered 1633 1595 -38 sock_queue_rcv_skb_reason 126 76 -50 tun_net_xmit 1127 1074 -53 __sk_receive_skb 690 632 -58 udpv6_queue_rcv_one_skb 935 869 -66 udp_queue_rcv_one_skb 919 853 -66 tcp_filter 154 - -154 Total: Before=29722783, After=29722212, chg -0.00% Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260409145625.2306224-6-edumazet@google.com Signed-off-by: Jakub Kicinski

net: change sk_filter_reason() to return the reason by value

2026-04-12T21:30:25+00:00

sk_filter_trim_cap will soon return the reason by value, do the same for sk_filter_reason(). $ scripts/bloat-o-meter -t vmlinux.old vmlinux.new add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-21 (-21) Function old new delta sock_queue_rcv_skb_reason 128 126 -2 tun_net_xmit 1146 1127 -19 Total: Before=29722661, After=29722640, chg -0.00% Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260409145625.2306224-4-edumazet@google.com Signed-off-by: Jakub Kicinski

net: change sock_queue_rcv_skb_reason() to return a drop_reason

2026-04-12T21:30:25+00:00

Change sock_queue_rcv_skb_reason() to return the drop_reason directly instead of using a reference. This is part of an effort to remove stack canaries and reduce bloat. $ scripts/bloat-o-meter -t vmlinux.old vmlinux.new add/remove: 0/0 grow/shrink: 3/7 up/down: 79/-301 (-222) Function old new delta vsock_queue_rcv_skb 50 79 +29 ipmr_cache_report 1290 1315 +25 ip6mr_cache_report 1322 1347 +25 packet_rcv_spkt 329 327 -2 sock_queue_rcv_skb_reason 166 128 -38 raw_rcv_skb 122 80 -42 ping_queue_rcv_skb 109 61 -48 ping_rcv 215 162 -53 rawv6_rcv_skb 278 224 -54 raw_rcv 591 527 -64 Total: Before=29722890, After=29722668, chg -0.00% Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260409145625.2306224-2-edumazet@google.com Signed-off-by: Jakub Kicinski