Syzkaller found a way to trigger division by zero
in mptcp_subflow_cleanup_rbuf().
The current checks implemented into tcp_can_send_ack()
are too week, let's be more accurate.
Reported-by: Christoph Paasch <cpaa...@apple.com>
Fixes: ea4ca586b16f ("mptcp: refine MPTCP-level ack scheduling")
Fixes: fd8976790a6c ("mptcp: be careful on MPTCP-level ack.")
Signed-off-by: Paolo Abeni <pab...@redhat.com>
---
net/mptcp/protocol.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 6628d8d74203..2ff8c7caf74f 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -427,7 +427,7 @@ static bool mptcp_subflow_active(struct
mptcp_subflow_context *subflow)
static bool tcp_can_send_ack(const struct sock *ssk)
{
return !((1 << inet_sk_state_load(ssk)) &
- (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE));
+ (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE |
TCPF_LISTEN));
}
static void mptcp_send_ack(struct mptcp_sock *msk)
--
2.26.2
