From d119775f2bad827edc28071c061fdd4a91f889a5 Mon Sep 17 00:00:00 2001 From: Jiexun Wang Date: Wed, 6 May 2026 22:08:23 +0800 Subject: [PATCH] af_unix: Reject SIOCATMARK on non-stream sockets SIOCATMARK reports whether the receive queue is at the urgent mark for MSG_OOB. In AF_UNIX, MSG_OOB is supported only for SOCK_STREAM sockets. SOCK_DGRAM and SOCK_SEQPACKET reject MSG_OOB in sendmsg() and recvmsg(), so they should not support SIOCATMARK either. Return -EOPNOTSUPP for non-stream sockets before checking the receive queue. Fixes: 314001f0bf92 ("af_unix: Add OOB support") Cc: stable@kernel.org Reported-by: Yuan Tan Reported-by: Yifan Wu Reported-by: Juefei Pu Reported-by: Xin Liu Suggested-by: Kuniyuki Iwashima Signed-off-by: Jiexun Wang Signed-off-by: Ren Wei Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20260506140825.2987635-1-n05ec@lzu.edu.cn Signed-off-by: Jakub Kicinski --- net/unix/af_unix.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index e2d787ca3e74..1cbf36ea043b 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -3323,6 +3323,9 @@ static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) struct sk_buff *skb; int answ = 0; + if (sk->sk_type != SOCK_STREAM) + return -EOPNOTSUPP; + mutex_lock(&u->iolock); skb = skb_peek(&sk->sk_receive_queue); -- 2.47.3