From: Frank van der Linden <fllinden@amazon.com>
Date: Tue, 12 Jun 2018 23:09:37 +0000 (+0000)
Subject: tcp: verify the checksum of the first data segment in a new connection
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=39f4ae01c1d6c6891b46d6cb1f3f869823bac21a;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

tcp: verify the checksum of the first data segment in a new connection

[ Upstream commit 4fd44a98ffe0d048246efef67ed640fdf2098a62 ]

commit 079096f103fa ("tcp/dccp: install syn_recv requests into ehash
table") introduced an optimization for the handling of child sockets
created for a new TCP connection.

But this optimization passes any data associated with the last ACK of the
connection handshake up the stack without verifying its checksum, because it
calls tcp_child_process(), which in turn calls tcp_rcv_state_process()
directly.  These lower-level processing functions do not do any checksum
verification.

Insert a tcp_checksum_complete call in the TCP_NEW_SYN_RECEIVE path to
fix this.

Fixes: 079096f103fa ("tcp/dccp: install syn_recv requests into ehash table")
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Tested-by: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index cab4b935e474..a95ccdceb797 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1675,6 +1675,10 @@ process:
 			reqsk_put(req);
 			goto discard_it;
 		}
+		if (tcp_checksum_complete(skb)) {
+			reqsk_put(req);
+			goto csum_error;
+		}
 		if (unlikely(sk->sk_state != TCP_LISTEN)) {
 			inet_csk_reqsk_queue_drop_and_put(sk, req);
 			goto lookup;
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 237cc6187c5a..35e8aef9ceed 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1453,6 +1453,10 @@ process:
 			reqsk_put(req);
 			goto discard_it;
 		}
+		if (tcp_checksum_complete(skb)) {
+			reqsk_put(req);
+			goto csum_error;
+		}
 		if (unlikely(sk->sk_state != TCP_LISTEN)) {
 			inet_csk_reqsk_queue_drop_and_put(sk, req);
 			goto lookup;