CVE-2016-9602 Qemu: 9p: virtfs allows guest to access host filesystem

[P J P <ppandit () redhat com>]

  Hello,

Quick Emulator(Qemu) built with the VirtFS, host directory sharing via Plan 9 
File System(9pfs) support, is vulnerable to an improper link following issue. 
It could occur while accessing symbolic link files on a shared host directory.

A privileged user inside guest could use this flaw to access host file system 
beyond the shared folder and potentially escalating their privileges on a 
host.

Reference:
----------
  -> http://wiki.qemu.org/Documentation/9psetup
  -> https://bugzilla.redhat.com/show_bug.cgi?id=1413929


Please see a proposed patch to fix this issue attached herein.

This issue was discovered by Jann Horn of Google Project Zero.

'CVE-2016-9602' has been assigned to this issue by Red Hat Inc.

Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
47AF CE69 3A90 54AA 9045 1053 DD13 3D32 FE5B 041F

Attachment: qemu-9pfs-only-allow-directories-during-walk.patch
Description: