4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Frank van der Linden fllinden@amazon.com
[ 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 --- net/ipv4/tcp_ipv4.c | 4 ++++ net/ipv6/tcp_ipv6.c | 4 ++++ 2 files changed, 8 insertions(+)
--- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1627,6 +1627,10 @@ 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; --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1415,6 +1415,10 @@ 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;