mptcp: don't leak msk in token container

If a listening MPTCP socket has unaccepted sockets at close
time, the related msks are freed via mptcp_sock_destruct(),
which in turn does not invoke the proto->destroy() method
nor the mptcp_token_destroy() function.

Due to the above, the child msk socket is not removed from
the token container, leading to later UaF.

Address the issue explicitly removing the token even in the
above error path.

Fixes: 79c0949e9a09 ("mptcp: Add key generation and token tree")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 493b98a0825c02182b1268f1f2e9ae929777d865..bf132575040d115591d1ebcc0cab1932c1d86510 100644 (file)
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -393,6 +393,7 @@ static void mptcp_sock_destruct(struct sock *sk)
                sock_orphan(sk);
        }
 
+       mptcp_token_destroy(mptcp_sk(sk)->token);
        inet_sock_destruct(sk);
 }