From: Yun Lu <luyun@kylinos.cn> stable inclusion from stable-v5.10.241 commit dbf3580aec1fed8143917efffd195838d894a7dd category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18208 CVE: CVE-2026-74668 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit c1ba3c0cbdb5e53a8ec5d708e99cd4c497028a13 upstream. Due to the changes in commit 581073f626e3 ("af_packet: do not call packet_read_pending() from tpacket_destruct_skb()"), every time tpacket_destruct_skb() is executed, the skb_completion is marked as completed. When wait_for_completion_interruptible_timeout() returns completed, the pending_refcnt has not yet been reduced to zero. Therefore, when ph is NULL, the wait function may need to be called multiple times until packet_read_pending() finally returns zero. We should call sock_sndtimeo() only once, otherwise the SO_SNDTIMEO constraint could be way off. Fixes: 581073f626e3 ("af_packet: do not call packet_read_pending() from tpacket_destruct_skb()") Cc: stable@kernel.org Suggested-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Yun Lu <luyun@kylinos.cn> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: JiangJieHua <jiangjiehua1@huawei.com> --- net/packet/af_packet.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 4b640bab5a7d9..64dc01fb2c28d 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2694,7 +2694,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg) int len_sum = 0; int status = TP_STATUS_AVAILABLE; int hlen, tlen, copylen = 0; - long timeo = 0; + long timeo; mutex_lock(&po->pg_vec_lock); @@ -2748,6 +2748,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg) if ((size_max > dev->mtu + reserve + VLAN_HLEN) && !po->has_vnet_hdr) size_max = dev->mtu + reserve + VLAN_HLEN; + timeo = sock_sndtimeo(&po->sk, msg->msg_flags & MSG_DONTWAIT); reinit_completion(&po->skb_completion); do { @@ -2755,7 +2756,6 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg) TP_STATUS_SEND_REQUEST); if (unlikely(ph == NULL)) { if (need_wait && skb) { - timeo = sock_sndtimeo(&po->sk, msg->msg_flags & MSG_DONTWAIT); timeo = wait_for_completion_interruptible_timeout(&po->skb_completion, timeo); if (timeo <= 0) { err = !timeo ? -ETIMEDOUT : -ERESTARTSYS; -- 2.33.8