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| author | Eric Dumazet <edumazet@google.com> | 2017-02-01 08:33:53 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-02-01 12:55:42 -0500 |
| commit | 06425c308b92eaf60767bc71d359f4cbc7a561f8 (patch) | |
| tree | a08cfa26bccb18c96d087ee257d8a99f0f804f53 | |
| parent | 63117f09c768be05a0bf465911297dc76394f686 (diff) | |
| download | linux-stable-06425c308b92eaf60767bc71d359f4cbc7a561f8.tar.gz linux-stable-06425c308b92eaf60767bc71d359f4cbc7a561f8.tar.bz2 linux-stable-06425c308b92eaf60767bc71d359f4cbc7a561f8.zip | |
tcp: fix 0 divide in __tcp_select_window()
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>
| -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 1d5331a1b1dc..8ce50dc3ab8c 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2518,9 +2518,11 @@ 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; |