Bug 824919 (CVE-2012-2652) - CVE-2012-2652 qemu: vulnerable to temporary file symlink attacks
Summary: CVE-2012-2652 qemu: vulnerable to temporary file symlink attacks
Alias: CVE-2012-2652
Product: Security Response
Classification: Other
Component: vulnerability   
(Show other bugs)
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Whiteboard: impact=moderate,public=20120528,repor...
Keywords: Security
Depends On: 825686 825687 825690 825691 825697
Blocks: 824924
TreeView+ depends on / blocked
Reported: 2012-05-24 15:35 UTC by Vincent Danen
Modified: 2014-11-20 20:09 UTC (History)
19 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Last Closed: 2013-08-24 13:31:40 UTC
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)

Description Vincent Danen 2012-05-24 15:35:39 UTC
A flaw was found in how qemu, in snapshot mode (-snapshot command line argument), handled the creation and opening of the temporary file used to store the difference of the virtualized guest's read-only image and the current state.  In snapshot mode, bdrv_open() creates an empty temporary file without checking for any mkstemp() or close() failures; it also ignores the possibility of a buffer overrun given an exceptionally long $TMPDIR.  Because qemu re-opens that file after creation, it is possible to race qemu and insert a symbolic link with the same expected name as the temporary file, pointing to an attacker-chosen file.  This can be used to either overwrite the destination file with the privileges of the user running qemu (typically root), or to point to an attacker-readable file that could expose data from the guest to the attacker.

This flaw has been assigned the name CVE-2012-2652.

Comment 1 Jim Meyering 2012-05-28 07:32:05 UTC
To accommodate the imminent release of qemu-1.1,
I've posted the report and patch on the upstream mailing list:


Comment 5 Petr Matousek 2012-05-28 08:55:15 UTC
Created qemu tracking bugs for this issue

Affects: fedora-all [bug 825697]

Comment 9 Fedora Update System 2012-08-09 22:59:55 UTC
qemu-0.15.1-7.fc16 has been pushed to the Fedora 16 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 10 Fedora Update System 2012-08-09 23:02:02 UTC
qemu-1.0.1-1.fc17 has been pushed to the Fedora 17 stable repository.  If problems still persist, please make note of it in this bug report.

Note You need to log in before you can comment on or make changes to this bug.