Bug 824919 - (CVE-2012-2652) CVE-2012-2652 qemu: vulnerable to temporary file symlink attacks
CVE-2012-2652 qemu: vulnerable to temporary file symlink attacks
Status: CLOSED ERRATA
Product: Security Response
Classification: Other
Component: vulnerability (Show other bugs)
unspecified
All Linux
medium Severity medium
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Assigned To: Red Hat Product Security
impact=moderate,public=20120528,repor...
: Security
Depends On: 825686 825687 825690 825691 825697
Blocks: 824924
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Reported: 2012-05-24 11:35 EDT by Vincent Danen
Modified: 2014-11-20 15:09 EST (History)
19 users (show)

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Doc Type: Bug Fix
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Last Closed: 2013-08-24 09:31:40 EDT
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RHEL 7.3 requirements from Atomic Host:


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Description Vincent Danen 2012-05-24 11:35:39 EDT
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 03:32:05 EDT
To accommodate the imminent release of qemu-1.1,
I've posted the report and patch on the upstream mailing list:

  http://marc.info/?l=qemu-devel&m=133819025731504&w=2
Comment 5 Petr Matousek 2012-05-28 04:55:15 EDT
Created qemu tracking bugs for this issue

Affects: fedora-all [bug 825697]
Comment 9 Fedora Update System 2012-08-09 18:59:55 EDT
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 19:02:02 EDT
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.

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