Linux kernel: CVE-2017-9242: out-of-bounds write in __ip6_append_data

[Andrey Konovalov <andreyknvl () google com>]

The following CVE was assigned for an out-of-bounds write in IPv6
socket buffers.

The bug was found with syzkaller.

* CVE-2017-9242

The __ip6_append_data function in net/ipv6/ip6_output.c in the Linux
kernel through 4.11.3 is too late in checking whether an overwrite of
an skb data structure may occur, which allows local users to cause a
denial of service (system crash) via crafted system calls.

CVE: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-9242
Fix: 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=232cd35d0804cc241eb887bb8d4d9b3b9881c64a