diff options
| author | Yuchung Cheng <ycheng@google.com> | 2018-04-25 11:33:08 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-04-27 11:49:31 -0400 |
| commit | 16ae6aa1705299789f71fdea59bfb119c1fbd9c0 (patch) | |
| tree | 5ffa75389f1bcb7a45d39374bf20bf497e2169e1 /net | |
| parent | cc2180a5880d0fd8491182cdc65e8df9696a7c9e (diff) | |
| download | linux-16ae6aa1705299789f71fdea59bfb119c1fbd9c0.tar.gz | |
tcp: ignore Fast Open on repair mode
The TCP repair sequence of operation is to first set the socket in repair mode, then inject the TCP stats into the socket with repair socket options, then call connect() to re-activate the socket. The connect syscall simply returns and set state to ESTABLISHED mode. As a result Fast Open is meaningless for TCP repair. However allowing sendto() system call with MSG_FASTOPEN flag half-way during the repair operation could unexpectedly cause data to be sent, before the operation finishes changing the internal TCP stats (e.g. MSS). This in turn triggers TCP warnings on inconsistent packet accounting. The fix is to simply disallow Fast Open operation once the socket is in the repair mode. Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 9ce1c726185e..4b18ad41d4df 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1204,7 +1204,8 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) uarg->zerocopy = 0; } - if (unlikely(flags & MSG_FASTOPEN || inet_sk(sk)->defer_connect)) { + if (unlikely(flags & MSG_FASTOPEN || inet_sk(sk)->defer_connect) && + !tp->repair) { err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size); if (err == -EINPROGRESS && copied_syn > 0) goto out; |