tcp: fix 0 divide in __tcp_select_window()
authorEric Dumazet <edumazet@google.com>
Wed, 1 Feb 2017 16:33:53 +0000 (08:33 -0800)
committerDavid S. Miller <davem@davemloft.net>
Wed, 1 Feb 2017 17:55:42 +0000 (12:55 -0500)
commit06425c308b92eaf60767bc71d359f4cbc7a561f8
treea08cfa26bccb18c96d087ee257d8a99f0f804f53
parent63117f09c768be05a0bf465911297dc76394f686
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>
net/ipv4/tcp_output.c