This is a note to let you know that I've just added the patch titled tcp: initialize tp->copied_seq in case of cross SYN connection to the 3.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: tcp-initialize-tp-copied_seq-in-case-of-cross-syn-connection.patch and it can be found in the queue-3.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Fri Dec 11 11:39:46 EST 2015 From: Eric Dumazet <edumazet@xxxxxxxxxx> Date: Thu, 26 Nov 2015 08:18:14 -0800 Subject: tcp: initialize tp->copied_seq in case of cross SYN connection From: Eric Dumazet <edumazet@xxxxxxxxxx> [ 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 <edumazet@xxxxxxxxxx> Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Tested-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv4/tcp_input.c | 1 + 1 file changed, 1 insertion(+) --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5575,6 +5575,7 @@ 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 Patches currently in stable-queue which might be from edumazet@xxxxxxxxxx are queue-3.10/packet-infer-protocol-from-ethernet-header-if-unset.patch queue-3.10/ipv6-sctp-implement-sctp_v6_destroy_sock.patch queue-3.10/net-scm-fix-pax-detected-msg_controllen-overflow-in-scm_detach_fds.patch queue-3.10/tcp-md5-fix-lockdep-annotation.patch queue-3.10/tcp-initialize-tp-copied_seq-in-case-of-cross-syn-connection.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html