This is a note to let you know that I've just added the patch titled
mptcp: fix locking for setsockopt corner-case
to the 6.1-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:
mptcp-fix-locking-for-setsockopt-corner-case.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit fece5c1a01a999db819c9829adf15e07a33069a5
Author: Paolo Abeni <pabeni@xxxxxxxxxx>
Date: Tue Feb 7 14:04:14 2023 +0100
mptcp: fix locking for setsockopt corner-case
[ Upstream commit 21e43569685de4ad773fb060c11a15f3fd5e7ac4 ]
We need to call the __mptcp_nmpc_socket(), and later subflow socket
access under the msk socket lock, or e.g. a racing connect() could
change the socket status under the hood, with unexpected results.
Fixes: 54635bd04701 ("mptcp: add TCP_FASTOPEN_CONNECT socket option")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Reviewed-by: Matthieu Baerts <matthieu.baerts@xxxxxxxxxxxx>
Signed-off-by: Matthieu Baerts <matthieu.baerts@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 8d3b09d75c3ae..696ba398d699a 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -772,14 +772,21 @@ static int mptcp_setsockopt_sol_tcp_defer(struct mptcp_sock *msk, sockptr_t optv
static int mptcp_setsockopt_first_sf_only(struct mptcp_sock *msk, int level, int optname,
sockptr_t optval, unsigned int optlen)
{
+ struct sock *sk = (struct sock *)msk;
struct socket *sock;
+ int ret = -EINVAL;
/* Limit to first subflow, before the connection establishment */
+ lock_sock(sk);
sock = __mptcp_nmpc_socket(msk);
if (!sock)
- return -EINVAL;
+ goto unlock;
- return tcp_setsockopt(sock->sk, level, optname, optval, optlen);
+ ret = tcp_setsockopt(sock->sk, level, optname, optval, optlen);
+
+unlock:
+ release_sock(sk);
+ return ret;
}
static int mptcp_setsockopt_sol_tcp(struct mptcp_sock *msk, int optname,
