From 4fd44a98ffe0d048246efef67ed640fdf2098a62 Mon Sep 17 00:00:00 2001 From: Frank van der Linden Date: Tue, 12 Jun 2018 23:09:37 +0000 Subject: [PATCH] tcp: verify the checksum of the first data segment in a new connection 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 Signed-off-by: Eric Dumazet Tested-by: Balbir Singh Reviewed-by: Balbir Singh Signed-off-by: David S. Miller --- net/ipv4/tcp_ipv4.c | 4 ++++ net/ipv6/tcp_ipv6.c | 4 ++++ 2 files changed, 8 insertions(+) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index fed3f1c66167..bea17f1e8302 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1730,6 +1730,10 @@ 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 b620d9b72e59..7efa9fd7e109 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1479,6 +1479,10 @@ 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;