diff options
| author | Eric Dumazet <edumazet@google.com> | 2017-02-01 08:33:53 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-02-18 16:39:26 +0100 |
| commit | f3ece3b38437fd06b60a74cd640d95f8d32f5b96 (patch) | |
| tree | b3db8741fa60501fe94b8bf3bc3cacb134571c67 | |
| parent | 3f5b5134ec7c9418415e4e660adebe6c6ec112fd (diff) | |
tcp: fix 0 divide in __tcp_select_window()
[ Upstream commit 06425c308b92eaf60767bc71d359f4cbc7a561f8 ]
syszkaller fuzzer was able to trigger a divide by zero, when
TCP window scaling is not enabled.
SO_RCVBUF can be used not only to increase sk_rcvbuf, also
to decrease it below current receive buffers utilization.
If mss is negative or 0, just return a zero TCP window.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/ipv4/tcp_output.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 0795647e94c6..de95714d021c 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2383,9 +2383,11 @@ u32 __tcp_select_window(struct sock *sk) int full_space = min_t(int, tp->window_clamp, allowed_space); int window; - if (mss > full_space) + if (unlikely(mss > full_space)) { mss = full_space; - + if (mss <= 0) + return 0; + } if (free_space < (full_space >> 1)) { icsk->icsk_ack.quick = 0; |