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

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Date: Tue, 17 Jan 2017 17:48:59 +0530 (IST)
From: P J P <ppandit@...hat.com>
To: oss security list <oss-security@...ts.openwall.com>
cc: Jann Horn <jannh@...gle.com>, Greg Kurz <groug@...d.org>
Subject: CVE-2016-9602 Qemu: 9p: virtfs allows guest to access host
 filesystem

   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
View attachment "qemu-9pfs-only-allow-directories-during-walk.patch" of type "text/plain" (1785 bytes)

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