mptcp: fix setsockopt(IP_TOS) subflow locking

The mptcp implementation of the IP_TOS socket option uses the lockless variant of the TOS manipulation helper and does not hold suck lock at the helper invocation time. Add the required locking. Fixes: ffcacff ("mptcp: Support for IP_TOS for MPTCP setsockopt()") Closes: multipath-tcp/mptcp_net-next#457 Signed-off-by: Paolo Abeni <[email protected]>
intel-lab-lkp · Nov 8, 2023 · 88da875 · 88da875
1 parent 22dcc06
commit 88da875
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
@@ -738,8 +738,11 @@ static int mptcp_setsockopt_v4_set_tos(struct mptcp_sock *msk, int optname,
 	val = READ_ONCE(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);