CVE-2014-7840

Updated qemu packages fix security vulnerabilities:

During migration, the values read from migration stream during ram load are not validated. Especially offset in host_from_stream_offset() and also the length of the writes in the callers of the said function. A user able to alter the savevm data (either on the disk or over the wire during migration) could use either of these flaws to corrupt QEMU process memory on the (destination) host, which could potentially result in arbitrary code execution on the host with the privileges of the QEMU process (CVE-2014-7840).

Paolo Bonzini of Red Hat discovered that the blit region checks were insufficient in the Cirrus VGA emulator in qemu. A privileged guest user could use this flaw to write into qemu address space on the host, potentially escalating their privileges to those of the qemu host process (CVE-2014-8106).

QEMU was updated to fix various bugs and security issues.

Following security issues were fixed: CVE-2014-8106: Heap-based buffer overflow in the Cirrus VGA emulator (hw/display/cirrus_vga.c) in QEMU allowed local guest users to execute arbitrary code via vectors related to blit regions.

CVE-2014-7840: The host_from_stream_offset function in arch_init.c in QEMU, when loading RAM during migration, allowed remote attackers to execute arbitrary code via a crafted (1) offset or (2) length value in savevm data.

Also a bug was fixed where qemu-img convert could occasionaly corrupt images. (bsc#908380)

This collective update for KVM and libvirt provides fixes for security and non-security issues.

kvm:

* Fix NULL pointer dereference because of uninitialized UDP socket.
  (bsc#897654, CVE-2014-3640)
* Fix performance degradation after migration. (bsc#878350)
* Fix potential image corruption due to missing FIEMAP_FLAG_SYNC flag
  in FS_IOC_FIEMAP ioctl. (bsc#908381)
* Add validate hex properties for qdev. (bsc#852397)
* Add boot option to do strict boot (bsc#900084)
* Add query-command-line-options QMP command. (bsc#899144)
* Fix incorrect return value of migrate_cancel. (bsc#843074)
* Fix insufficient parameter validation during ram load. (bsc#905097,
  CVE-2014-7840)
* Fix insufficient blit region checks in qemu/cirrus. (bsc#907805,
  CVE-2014-8106)

libvirt:

* Fix security hole with migratable flag in dumpxml. (bsc#904176,
  CVE-2014-7823)
* Fix domain deadlock. (bsc#899484, CVE-2014-3657)
* Use correct definition when looking up disk in qemu blkiotune.
  (bsc#897783, CVE-2014-3633)
* Fix undefined symbol when starting virtlockd. (bsc#910145)
* Add '-boot strict' to qemu's commandline whenever possible.
  (bsc#900084)
* Add support for 'reboot-timeout' in qemu. (bsc#899144)
* Increase QEMU's monitor timeout to 30sec. (bsc#911742)
* Allow setting QEMU's migration max downtime any time. (bsc#879665)

Security Issues:

* CVE-2014-7823
  <http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-7823>
* CVE-2014-3657
  <http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-3657>
* CVE-2014-3633
  <http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-3633>
* CVE-2014-3640
  <http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-3640>
* CVE-2014-7840
  <http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-7840>
* CVE-2014-8106
  <http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-8106>

The host_from_stream_offset function in arch_init.c in QEMU, when loading RAM during migration, allows remote attackers to execute arbitrary code via a crafted (1) offset or (2) length value in savevm data.

Michael S. Tsirkin discovered that QEMU incorrectly handled certain parameters during ram load while performing a migration. An attacker able to manipulate savevm data could use this issue to possibly execute arbitrary code on the host. This issue only affected Ubuntu 12.04 LTS, Ubuntu 14.04 LTS, and Ubuntu 14.10. (CVE-2014-7840)

Paolo Bonzini discovered that QEMU incorrectly handled memory in the Cirrus VGA device. A malicious guest could possibly use this issue to write into memory of the host, leading to privilege escalation. (CVE-2014-8106)