Bug 1418944 – CVE-2017-5884 gtk-vnc: Improper check of framebuffer boundaries when processing a tile

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Bug 1418944 - (CVE-2017-5884) CVE-2017-5884 gtk-vnc: Improper check of framebuffer boundaries when processing a tile

Summary:	CVE-2017-5884 gtk-vnc: Improper check of framebuffer boundaries when processi...

Status:	NEW

Aliases:	CVE-2017-5884

Product:	Security Response
Classification:	Other
Component:	vulnerability (Show other bugs)
Sub Component:
Version:	unspecified
Hardware:	All Linux

Priority	low Severity low
Target Milestone:	---
Target Release:	---
Assigned To:	Red Hat Product Security
QA Contact:
Docs Contact:

URL:
Whiteboard:	impact=low,public=20170201,reported=2...
Keywords:	Security

Depends On:	1418955 1418956 1425367
Blocks:	1415638 1418954
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Reported:	2017-02-03 03:52 EST by Adam Mariš
Modified:	2018-07-18 11:14 EDT (History)
CC List:	18 users (show)

See Also:
Fixed In Version:
Doc Type:	If docs needed, set a value
Doc Text:	It was found that gtk-vnc lacked proper bounds checking while processing messages using RRE, hextile, or copyrect encodings. A remote malicious VNC server could use this flaw to crash VNC viewers which are based on the gtk-vnc library.
Story Points:	---
Clone Of:
Environment:
Last Closed:
Type:	---
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

Attachments	(Terms of Use)
Add an attachment (proposed patch, testcase, etc.)

External Trackers
Tracker	ID	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHSA-2017:2258	normal	SHIPPED_LIVE	Moderate: gtk-vnc security, bug fix, and enhancement update	2017-08-01 14:21:01 EDT

Groups: None (edit)

Description Adam Mariš 2017-02-03 03:52:02 EST

It was found that gtk-vnc does not properly check boundaries of subrectangle-containing tiles. A malicious server can use this to overwrite parts of the client memory, potentially leading to code execution under privileges of the user running the VNC client.

Upstream bug:

https://bugzilla.gnome.org/show_bug.cgi?id=778048

Upstream patch:

https://git.gnome.org/browse/gtk-vnc/commit/?id=ea0386933214c9178

Comment 1 Adam Mariš 2017-02-03 04:12:42 EST

Created gtk-vnc tracking bugs for this issue:

Affects: fedora-all [bug 1418955]

Comment 2 Adam Mariš 2017-02-03 04:13:00 EST

Created mingw-gtk-vnc tracking bugs for this issue:

Affects: fedora-all [bug 1418956]

Comment 3 Adam Mariš 2017-02-06 03:45:06 EST

CVE assignment:

http://openwall.com/lists/oss-security/2017/02/05/5

CVE covers all issues mentioned in https://bugzilla.gnome.org/show_bug.cgi?id=778048#c1

Comment 4 Daniel Berrange 2017-02-07 09:13:49 EST

Upstream fix in git master is

commit ea0386933214c9178aaea9f2f85049ea3fa3e14a
Author: Daniel P. Berrange <berrange@redhat.com>
Date:   Thu Feb 2 17:34:47 2017 +0000

    Fix bounds checking for RRE, hextile & copyrect encodings
    
    While the client would bounds check the overall update
    region, it failed to bounds check the payload data
    parameters.
    
    Add a test case to validate bounds checking.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=778048
    
    CVE-2017-5884
    
    Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

Comment 10 errata-xmlrpc 2017-08-01 15:56:49 EDT

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2017:2258 https://access.redhat.com/errata/RHSA-2017:2258

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