From: Paolo Abeni pabeni@redhat.com
[ 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@vger.kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Matthieu Baerts matthieu.baerts@tessares.net Signed-off-by: Matthieu Baerts matthieu.baerts@tessares.net Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/mptcp/sockopt.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
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,