2.6.32-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Eric Dumazet <[email protected]> [ Upstream commit 142a2e7ece8d8ac0e818eb2c91f99ca894730e2a ] Dmitry provided a syzkaller (http://github.com/google/syzkaller) generated program that triggers the WARNING at net/ipv4/tcp.c:1729 in tcp_recvmsg() : WARN_ON(tp->copied_seq != tp->rcv_nxt && !(flags & (MSG_PEEK | MSG_TRUNC))); His program is specifically attempting a Cross SYN TCP exchange, that we support (for the pleasure of hackers ?), but it looks we lack proper tcp->copied_seq initialization. Thanks again Dmitry for your report and testings. Signed-off-by: Eric Dumazet <[email protected]> Reported-by: Dmitry Vyukov <[email protected]> Tested-by: Dmitry Vyukov <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Ben Hutchings <[email protected]> (cherry picked from commit 6cfa9781d3bf950eed455369966bbdf9d05871c5) Signed-off-by: Willy Tarreau <[email protected]> --- net/ipv4/tcp_input.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index c821218..83c0eae 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5559,6 +5559,7 @@ discard: } tp->rcv_nxt = TCP_SKB_CB(skb)->seq + 1; + tp->copied_seq = tp->rcv_nxt; tp->rcv_wup = TCP_SKB_CB(skb)->seq + 1; /* RFC1323: The window in SYN & SYN/ACK segments is -- 1.7.12.2.21.g234cd45.dirty
