The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
Possible dependencies:
21e43569685d ("mptcp: fix locking for setsockopt corner-case")
d3d429047cc6 ("mptcp: sockopt: make 'tcp_fastopen_connect' generic")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 21e43569685de4ad773fb060c11a15f3fd5e7ac4 Mon Sep 17 00:00:00 2001
From: Paolo Abeni <pabeni@xxxxxxxxxx>
Date: Tue, 7 Feb 2023 14:04:14 +0100
Subject: [PATCH] mptcp: fix locking for setsockopt corner-case
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>
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index d4b1e6ec1b36..7f2c3727ab23 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -760,14 +760,21 @@ static int mptcp_setsockopt_v4(struct mptcp_sock *msk, int optname,
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,
