Bug 1050928 (CVE-2014-0011)

Summary: CVE-2014-0011 tigervnc: ZRLE decoding heap-based buffer overflow in vncviewer
Product: [Other] Security Response Reporter: Ratul Gupta <ratulg>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED NOTABUG QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: jkurik, pfrields, scorneli, security-response-team, twaugh, vkrizan
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: tigervnc 1.3.1 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2014-03-19 20:04:58 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: 1048994, 1074555, 1078508    
Bug Blocks: 1050929    
Attachments:
Description Flags
tigervnc-CVE-2014-0011.patch (Fedora/master) none

Description Ratul Gupta 2014-01-09 11:24:08 UTC 
A heap-based buffer overflow was found in the way vncviewer rendered certain screen images from a vnc server. If a user could be tricked into connecting to a malicious vnc server, it may cause the vncviewer to crash, or could possibly execute arbitrary code with the permissions of the user running it.
Comment 14 Tomas Hoger 2014-03-11 15:56:58 UTC 
This issue was tracked to an issue in the ZRLE_DECODE() function which perform RLE decoding.  The function already contained boundary checks inside assert().  Those checks were, however, disabled in builds with NDEBUG, such as tigervnc packages in Fedora.

The tigervnc packages in Red Hat Enterprise Linux 6, and the vnc packages in Red Hat Enterprise Linux 5, were not built with NDEBUG and have those checks enabled.  Therefore, they are not affected by this issue.

Tim Waugh prepared a patch that:
- replaces relevant asserts with explicit checks that raise exception
- changing build configuration to not use NDEBUG

Patch is attached as attachment 859269 [details]
Comment 15 Tomas Hoger 2014-03-19 17:16:16 UTC 
The issue is now fixed upstream in TigerVNC 1.3.1:
http://sourceforge.net/p/tigervnc/mailman/message/32120476/

Upstream commits (applying patch mentioned in commnet 14):
http://sourceforge.net/p/tigervnc/code/5163
http://sourceforge.net/p/tigervnc/code/5164
Comment 17 Tomas Hoger 2014-03-19 19:34:41 UTC 
Statement:

Not vulnerable. This issue did not affect the tigervnc packages as shipped with Red Hat Enterprise Linux 6, and the vnc packages as shipped with Red Hat Enterprise Linux 5.
Comment 18 Fedora Update System 2014-03-24 06:41:32 UTC 
tigervnc-1.3.0-14.fc20 has been pushed to the Fedora 20 stable repository.  If problems still persist, please make note of it in this bug report.
Comment 19 Fedora Update System 2014-04-05 04:56:37 UTC 
tigervnc-1.3.0-10.fc19 has been pushed to the Fedora 19 stable repository.  If problems still persist, please make note of it in this bug report.