From c8e74731fff0afdf4e5d52bd5f6a22efc5075608 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Tue, 14 Nov 2023 00:16:16 +0100 Subject: [PATCH] mptcp: fix setsockopt(IP_TOS) subflow locking commit 7679d34f97b7a09fd565f5729f79fd61b7c55329 upstream. The MPTCP implementation of the IP_TOS socket option uses the lockless variant of the TOS manipulation helper and does not hold such lock at the helper invocation time. Add the required locking. Fixes: ffcacff87cd6 ("mptcp: Support for IP_TOS for MPTCP setsockopt()") Cc: stable@vger.kernel.org Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/457 Signed-off-by: Paolo Abeni Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts Link: https://lore.kernel.org/r/20231114-upstream-net-20231113-mptcp-misc-fixes-6-7-rc2-v1-4-7b9cd6a7b7f4@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/mptcp/sockopt.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c index a3f1fe810cc9..7b878ea29e3a 100644 --- a/net/mptcp/sockopt.c +++ b/net/mptcp/sockopt.c @@ -737,8 +737,11 @@ static int mptcp_setsockopt_v4_set_tos(struct mptcp_sock *msk, int optname, val = inet_sk(sk)->tos; mptcp_for_each_subflow(msk, subflow) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); + bool slow; + slow = lock_sock_fast(ssk); __ip_sock_set_tos(ssk, val); + unlock_sock_fast(ssk, slow); } release_sock(sk);