Bug 1429936

Summary: subversion: SHA-1 collision causes repository breakage
Product: [Other] Security Response Reporter: Andrej Nemec <anemec>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED WONTFIX QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dmoppert, jorton, vanmeeuwen+fedora
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: subversion 1.8.18, subversion 1.9.6 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2019-06-08 03:08:47 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: 1429939    
Bug Blocks: 1429938    

Comment 1 Andrej Nemec 2017-03-07 14:31:30 UTC
Created subversion tracking bugs for this issue:

Affects: fedora-all [bug 1429939]

Comment 3 Doran Moppert 2017-04-03 05:19:09 UTC
Mitigation:

If you have a Subversion repository which accepts commits from untrusted users, installing the following script as a commit hook will reject files which correspond to known SHA-1 collisions.

https://svn.apache.org/viewvc/subversion/trunk/tools/hook-scripts/reject-known-sha1-collisions.sh?view=log

Further measures to protect the repository or recover from a malicious commit are described in this mailing list post:

https://svn.haxx.se/dev/archive-2017-02/0174.shtml

Comment 4 Doran Moppert 2017-04-04 06:36:28 UTC
subversion-1.6 is not impacted as badly by this issue because it does not include the `enable-rep-sharing` feature.  If two colliding files are committed, they can both be checked out correctly.  On subversion-1.7 this is not the case unless `enable-rep-sharing` has been set to `false` in the repository configuration.

This issue does not appear to cause any irrecoverable damage to the affected repository.  Downstream components such as trac can be adversely affected until one of the colliding files is removed.

Comment 5 Doran Moppert 2017-04-04 06:40:39 UTC
Statement:

Red Hat Product Security has rated this issue as having Moderate security impact. This issue is not currently planned to be addressed in future updates. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.

Comment 6 Adam Mariš 2017-07-04 08:19:33 UTC
External References:

https://subversion.apache.org/security/sha1-advisory.txt