This is a note to let you know that I've just added the patch titled
tcp: fix 0 divide in __tcp_select_window()
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tcp-fix-0-divide-in-__tcp_select_window.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Tue Feb 14 17:03:08 PST 2017
From: Eric Dumazet <edumazet@xxxxxxxxxx>
Date: Wed, 1 Feb 2017 08:33:53 -0800
Subject: tcp: fix 0 divide in __tcp_select_window()
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ 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@xxxxxxxxxx>
Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Acked-by: Neal Cardwell <ncardwell@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/tcp_output.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2436,9 +2436,11 @@ 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;
Patches currently in stable-queue which might be from edumazet@xxxxxxxxxx are
queue-4.9/ipv6-pointer-math-error-in-ip6_tnl_parse_tlv_enc_lim.patch
queue-4.9/netlabel-out-of-bound-access-in-cipso_v4_validate.patch
queue-4.9/packet-round-up-linear-to-header-len.patch
queue-4.9/tun-read-vnet_hdr_sz-once.patch
queue-4.9/ipv6-fix-ip6_tnl_parse_tlv_enc_lim.patch
queue-4.9/l2tp-do-not-use-udp_ioctl.patch
queue-4.9/tcp-fix-0-divide-in-__tcp_select_window.patch
queue-4.9/can-fix-kernel-panic-at-security_sock_rcv_skb.patch
queue-4.9/net-introduce-device-min_header_len.patch
queue-4.9/macvtap-read-vnet_hdr_size-once.patch
queue-4.9/tcp-avoid-infinite-loop-in-tcp_splice_read.patch
queue-4.9/mlx4-invoke-softirqs-after-napi_reschedule.patch
queue-4.9/ipv6-tcp-add-a-missing-tcp_v6_restore_cb.patch
queue-4.9/ipv4-keep-skb-dst-around-in-presence-of-ip-options.patch
queue-4.9/net-use-a-work-queue-to-defer-net_disable_timestamp-work.patch
queue-4.9/ip6_gre-fix-ip6gre_err-invalid-reads.patch