[Devel] [PATCH RHEL7 COMMIT] ms/tcp: avoid infinite loop in tcp_splice_read()

[Konstantin Khorenko]

Please consider this to ReadyKernel.

https://readykernel.com/

--
Best regards,

Konstantin Khorenko,
Virtuozzo Linux Kernel Team

On 02/27/2017 04:53 PM, Konstantin Khorenko wrote:
> The commit is pushed to "branch-rh7-3.10.0-514.6.1.vz7.28.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
> after rh7-3.10.0-514.6.1.vz7.28.7
> ------>
> commit b207397b05680d0d47b484ff3090194eb10f5cc8
> Author: Eric Dumazet <edumazet at google.com>
> Date:   Fri Feb 3 14:59:38 2017 -0800
>
>     ms/tcp: avoid infinite loop in tcp_splice_read()
>
>     Splicing from TCP socket is vulnerable when a packet with URG flag is
>     received and stored into receive queue.
>
>     __tcp_splice_read() returns 0, and sk_wait_data() immediately
>     returns since there is the problematic skb in queue.
>
>     This is a nice way to burn cpu (aka infinite loop) and trigger
>     soft lockups.
>
>     Again, this gem was found by syzkaller tool.
>
>     Fixes: 9c55e01c0cc8 ("[TCP]: Splice receive support.")
>     Signed-off-by: Eric Dumazet <edumazet at google.com>
>     Reported-by: Dmitry Vyukov  <dvyukov at google.com>
>     Cc: Willy Tarreau <w at 1wt.eu>
>     Signed-off-by: David S. Miller <davem at davemloft.net>
>
>     https://jira.sw.ru/browse/PSBM-61135
>     https://bugzilla.redhat.com/show_bug.cgi?id=1426542
>     CVE-2017-6214 kernel: ipv4/tcp: Infinite loop in tcp_splice_read()
>
>     (cherry picked from commit ccf7abb93af09ad0868ae9033d1ca8108bdaec82)
>     Signed-off-by: Konstantin Khorenko <khorenko at virtuozzo.com>