Patch "af_unix: Annotate data-races around sk->sk_state in sendmsg() and recvmsg()." has been added to the 4.19-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    af_unix: Annotate data-races around sk->sk_state in sendmsg() and recvmsg().

to the 4.19-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     af_unix-annotate-data-races-around-sk-sk_state-in-se.patch
and it can be found in the queue-4.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit b7a2b87c044c2c6e416348bb66a7d4260a9add79
Author: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Date:   Tue Jun 4 09:52:33 2024 -0700

    af_unix: Annotate data-races around sk->sk_state in sendmsg() and recvmsg().
    
    [ Upstream commit 8a34d4e8d9742a24f74998f45a6a98edd923319b ]
    
    The following functions read sk->sk_state locklessly and proceed only if
    the state is TCP_ESTABLISHED.
    
      * unix_stream_sendmsg
      * unix_stream_read_generic
      * unix_seqpacket_sendmsg
      * unix_seqpacket_recvmsg
    
    Let's use READ_ONCE() there.
    
    Fixes: a05d2ad1c1f3 ("af_unix: Only allow recv on connected seqpacket sockets.")
    Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
    Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
    Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 5266908c65ec4..c01955ccf6b39 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1886,7 +1886,7 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
 		goto out_err;
 
 	if (msg->msg_namelen) {
-		err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
+		err = READ_ONCE(sk->sk_state) == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
 		goto out_err;
 	} else {
 		err = -ENOTCONN;
@@ -2088,7 +2088,7 @@ static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg,
 	if (err)
 		return err;
 
-	if (sk->sk_state != TCP_ESTABLISHED)
+	if (READ_ONCE(sk->sk_state) != TCP_ESTABLISHED)
 		return -ENOTCONN;
 
 	if (msg->msg_namelen)
@@ -2102,7 +2102,7 @@ static int unix_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg,
 {
 	struct sock *sk = sock->sk;
 
-	if (sk->sk_state != TCP_ESTABLISHED)
+	if (READ_ONCE(sk->sk_state) != TCP_ESTABLISHED)
 		return -ENOTCONN;
 
 	return unix_dgram_recvmsg(sock, msg, size, flags);
@@ -2298,7 +2298,7 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state,
 	size_t size = state->size;
 	unsigned int last_len;
 
-	if (unlikely(sk->sk_state != TCP_ESTABLISHED)) {
+	if (unlikely(READ_ONCE(sk->sk_state) != TCP_ESTABLISHED)) {
 		err = -EINVAL;
 		goto out;
 	}