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| author | Eric Dumazet <edumazet@google.com> | 2015-11-26 08:18:14 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-11-30 15:34:17 -0500 |
| commit | 142a2e7ece8d8ac0e818eb2c91f99ca894730e2a (patch) | |
| tree | 5450f107e0d9bec8edd1b7857b8a38b43175c9dc /net | |
| parent | 0f2c0d32e6536ad39c3e9589d42c53d0ee3bfa08 (diff) | |
| download | lwn-142a2e7ece8d8ac0e818eb2c91f99ca894730e2a.tar.gz lwn-142a2e7ece8d8ac0e818eb2c91f99ca894730e2a.zip | |
tcp: initialize tp->copied_seq in case of cross SYN connection
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@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp_input.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index a4a0b6b3bcf2..2d656eef7f8e 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5683,6 +5683,7 @@ 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 |