Arch Linux Security Advisory ASA-201507-21
=========================================
Severity: Critical
Date    : 2015-07-29
CVE-ID  : CVE-2015-3214 CVE-2015-5154 CVE-2015-5158
Package : qemu
Type    : multiple issues
Remote  : Yes
Link    : https://wiki.archlinux.org/title/CVE

Summary
======
The package qemu before version 2.3.0-5 is vulnerable to multiple issues
including arbitrary code execution, information disclosure and denial of
service.

Resolution
=========
Upgrade to 2.3.0-5.

# pacman -Syu "qemu>=2.3.0-5"

The problems have been fixed upstream but no release is available yet.

Workaround
=========
None.

Description
==========
- CVE-2015-3214 (information disclosure, arbitrary code execution)

An out-of-bounds memory access flaw, leading to memory corruption or
possibly an information leak, was found in QEMU's pit_ioport_read()
function. A privileged guest user in a QEMU guest, which had QEMU PIT
emulation enabled, could potentially, in rare cases, use this flaw to
execute arbitrary code on the host with the privileges of the hosting
QEMU process.

- CVE-2015-5154 (arbitrary code execution)

A heap overflow flaw was found in the way QEMU's IDE subsystem handled
I/O buffer access while processing certain ATAPI commands. A privileged
guest user in a guest with CDROM drive enabled could potentially use
this flaw to execute arbitrary code on the host with the privileges of
the host's QEMU process corresponding to the guest.

- CVE-2015-5158 (denial of service)

This is a guest-triggerable buffer overflow. The scsi_cdb_length returns
-1 as an error value, but the caller does not check it. Luckily, the
massive overflow means that QEMU will just SIGSEGV, leading to denial of
service of the guest system.

Impact
=====
A remote attacker is able to execute arbitrary code and take over the
qemu process elevating its privilege to that of the qemu process or
perform a denial of service attack to crash the guest system.

References
=========
http://xenbits.xen.org/xsa/advisory-138.html
https://access.redhat.com/security/cve/CVE-2015-3214
https://access.redhat.com/security/cve/CVE-2015-5154
https://access.redhat.com/security/cve/CVE-2015-5158
https://github.com/qemu/qemu/commit/d4862a87e31a
https://github.com/qemu/qemu/commit/c170aad8b057
https://github.com/qemu/qemu/commit/d2ff85854512
https://github.com/qemu/qemu/commit/cb72cba83021
https://github.com/qemu/qemu/commit/03441c3a4a42