Bug 929087 (CVE-2013-1846)

Summary: CVE-2013-1846 Subversion (mod_dav_svn): DoS (crash) via LOCK requests against an activity URL
Product: [Other] Security Response Reporter: Huzaifa S. Sidhpurwala <huzaifas>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: jkaluza, jlieskov, jorton, security-response-team
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Subversion 1.6.21, Subversion 1.7.9 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2013-11-18 13:13:43 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 947369, 947370, 947372, 947374, 948813    
Bug Blocks: 929099    
Attachments:
Description Flags
patch-against-1.6.20.patch
none
patch-against-1.7.8 none

Description Huzaifa S. Sidhpurwala 2013-03-29 08:40:55 UTC 
It was found that Subversion's mod_dav_svn Apache HTTPD server module will crash when a LOCK request is made against activity URLs. This can lead to a DoS. 

An activity URL is used by the server to map transactions in the repository to an incoming commit by a client.  They are created by using the MKACTIVITY http method on the activity URL the client wishes to create.  Activity URLs following the pattern of having /!svn/act/$uuid where $uuid is some unique id the client chooses to use.
The denial of service described here issues a LOCK request on an activity URL.  There is no meaning to this request in the DAV based HTTP  protocols that Subversion uses.  There is a flaw in mod_dav_svn that improperly tries to process this request instead of rejecting it and results in an attempt to access invalid memory (NULL).  The invalid memory access causes the httpd child process to segfault.

Acknowledgements:

Red Hat would like to thank the Apache Subversion project for reporting this issue. Upstream acknowledges Ben Reser as the original reporter of this flaw.
Comment 2 Huzaifa S. Sidhpurwala 2013-03-29 08:44:25 UTC 
Created attachment 717969 [details]
patch-against-1.6.20.patch
Comment 3 Huzaifa S. Sidhpurwala 2013-03-29 08:44:54 UTC 
Created attachment 717970 [details]
patch-against-1.7.8
Comment 5 Huzaifa S. Sidhpurwala 2013-04-04 09:09:27 UTC 
This issue affects the version of subversion as shipped with Red Hat Enterprise Linux 5 and 6.

This issue affects the version of subversion as shipped with Fedora 17 and Fedora 18.
Comment 6 Jan Lieskovsky 2013-04-05 12:29:43 UTC 
External References:

http://subversion.apache.org/security/CVE-2013-1846-advisory.txt
Comment 7 Jan Lieskovsky 2013-04-05 12:30:15 UTC 
Announcements:
http://mail-archives.apache.org/mod_mbox/subversion-announce/201304.mbox/%3CCADkdwvRoyVrZV12tgC0FMGrc6%2BMisd3qTcZ%2BDdpFGgTahkgAkQ%40mail.gmail.com%3E (v1.7.9)

http://mail-archives.apache.org/mod_mbox/subversion-announce/201304.mbox/%3CCADkdwvSTMLbn4q_KM3Ph2UOeSiPGhEK4%3DSvwEjaHW_GUGkYWPQ%40mail.gmail.com%3E (v1.6.21)
Comment 8 Jan Lieskovsky 2013-04-05 12:58:56 UTC 
Created subversion tracking bugs for this issue

Affects: fedora-all [bug 948813]
Comment 11 errata-xmlrpc 2013-04-11 17:49:19 UTC 
This issue has been addressed in following products:

  Red Hat Enterprise Linux 6
  Red Hat Enterprise Linux 5

Via RHSA-2013:0737 https://rhn.redhat.com/errata/RHSA-2013-0737.html