[Secure-testing-team] Bug#779194: kfreebsd-10: CVE-2014-0998: vt crash via ioctl

[Steven Chamberlain]

Package: src:kfreebsd-10
Version: 10.1~svn274115-2
Severity: grave
Tags: security upstream patch
Control: found -1 kfreebsd-10/10.0-3

Hi,

An unprivileged local user can trigger an out-of-bounds memory
access in the kernel via an ioctl to vt(4) (aka. newcons).
https://security.FreeBSD.org/patches/EN-15:01/vt.patch

Upstream's advisory only describes potential impact as a kernel panic.
The original researcher's advisory mentioned privilege escalation, but
it's ambiguous if that referred to this bug, and unclear if it could be
exploitable for that.

Debian GNU/kFreeBSD introduced newcons into 10.0-3 as a backport.
kfreebsd-10 in jessie/sid enables it by default.  So does
kfreebsd-11 in experimental.

kfreebsd-8 and -9 in wheezy are unaffected as they do not have newcons.

-- System Information:
Debian Release: jessie/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (500, 'stable')
Architecture: kfreebsd-amd64 (x86_64)

Kernel: kFreeBSD 9.0-2-amd64-xenhvm-ipsec
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash