Bug 1029664 (CVE-2013-4560) - CVE-2013-4560 lighttpd: Use after free if FAMMonitorDirectory fails
Summary: CVE-2013-4560 lighttpd: Use after free if FAMMonitorDirectory fails
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2013-4560
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1029666 1029667 1029669
Blocks:
TreeView+ depends on / blocked
 
Reported: 2013-11-12 21:22 UTC by Kurt Seifried
Modified: 2019-09-29 13:09 UTC (History)
6 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2015-09-05 19:10:11 UTC


Attachments (Terms of Use)

Description Kurt Seifried 2013-11-12 21:22:52 UTC
Stefan Bühler of the lighthttpd project reports:

 Use after free if FAMMonitorDirectory fails
=============================================

 Description
-------------

If the "fam" is enabled:

    server.stat-cache-engine = "fam"

and there are directories reachable from configured doc roots and aliases on 
which FAMMonitorDirectory fails (probably depends on file system), a remote 
client could trigger a DoS.

This bug was found with the clang static analyzer.

 Detailed analysis
-------------------

If FAMMonitorDirectory fails, the memory intended to store the context is 
released; some lines below the "version" compoment of that context is read.
Reading invalid data doesn't matter, but the memory access could trigger a 
segfault.

 Affected versions
-------------------

All versions before 1.4.33.

 Patch
-------

See http://download.lighttpd.net/lighttpd/security/lighttpd-1.4.33_fix_fam_use_after_free.patch

 Fixed in
----------

1.4.x: http://redmine.lighttpd.net/projects/lighttpd/repository/revisions/2921
1.4.34: not released yet (http://www.lighttpd.net/)

 Solutions or workaround
-------------------------

Don't enable "fam".

 References
------------

[1] http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-XXXX (TBD)
[2] http://redmine.lighttpd.net/projects/lighttpd/repository/revisions/2921/diff/

 GPG signatures
----------------

* http://download.lighttpd.net/lighttpd/security/lighttpd-1.4.33_fix_fam_use_after_free.patch.asc
* http://download.lighttpd.net/lighttpd/security/lighttpd_sa_2013_03.txt.asc

Comment 1 Kurt Seifried 2013-11-12 21:24:38 UTC
Created lighttpd tracking bugs for this issue:

Affects: fedora-all [bug 1029666]

Comment 2 Kurt Seifried 2013-11-12 21:26:28 UTC
Created lighttpd tracking bugs for this issue:

Affects: epel-all [bug 1029667]


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