From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit e05a5f510f26607616fecdd4ac136310c8bea56b ]
do_recvmmsg() can write to sk->sk_err from multiple threads.
As said before, many other points reading or writing sk_err
need annotations.
Fixes: 34b88a68f26a ("net: Fix use after free in the recvmmsg exit path")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
Reviewed-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/socket.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/socket.c b/net/socket.c
index 9c92c0e6c4da8..263fab8e49010 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -2909,7 +2909,7 @@ static int do_recvmmsg(int fd, struct mmsghdr __user *mmsg,
* error to return on the next call or if the
* app asks about it using getsockopt(SO_ERROR).
*/
- sock->sk->sk_err = -err;
+ WRITE_ONCE(sock->sk->sk_err, -err);
}
out_put:
fput_light(sock->file, fput_needed);
--
2.39.2
