tcp: Add a tcp_filter hook before handle ack packet

Currently in both ipv4 and ipv6 code path, the ack packet received when
sk at TCP_NEW_SYN_RECV state is not filtered by socket filter or cgroup
filter since it is handled from tcp_child_process and never reaches the
tcp_filter inside tcp_v4_rcv or tcp_v6_rcv. Adding a tcp_filter hooks
here can make sure all the ingress tcp packet can be correctly filtered.

Signed-off-by: Chenbo Feng <fengc@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index e20bcf0061af..d774bcd9a54b 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1729,6 +1729,8 @@ process:
                 }
                 if (nsk == sk) {
                         reqsk_put(req);
+                } else if (tcp_filter(sk, skb)) {
+                        goto discard_and_relse;
                 } else if (tcp_child_process(sk, nsk, skb)) {
                         tcp_v4_send_reset(nsk, skb);
                         goto discard_and_relse;