From: Eric Dumazet <eduma...@google.com> 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. https://jira.sw.ru/browse/PSBM-71285 Back-port of ML commit: 06425c308b92eaf60767bc71d359f4cbc7a561f8 Signed-off-by: Eric Dumazet <eduma...@google.com> Reported-by: Dmitry Vyukov <dvyu...@google.com> Acked-by: Neal Cardwell <ncardw...@google.com> Signed-off-by: David S. Miller <da...@davemloft.net> Signed-off-by: Stanislav Kinsburskiy <skinsbur...@virtuozzo.com> --- net/ipv4/tcp_output.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index f395a09..3d24481 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2295,9 +2295,11 @@ 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; _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel