[PATCH 4.19 011/139] af_unix: Annotate data-races around sk->sk_state in sendmsg() and recvmsg().

[Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>]

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>

[ 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>
---
 net/unix/af_unix.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

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;
 	}
-- 
2.43.0