Bug 1456763 (CVE-2017-6891)

Summary:	CVE-2017-6891 libtasn1: Stack-based buffer overflow in asn1_find_node()
Product:	[Other] Security Response	Reporter:	Adam Mariš <amaris>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	bkearney, bmcclain, cbillett, cfergeau, dblechte, eedri, erik-fedora, jmatthew, klember, lsurette, mgoldboi, michal.skrivanek, mike, mmccune, nmavrogi, ohadlevy, rbalakri, rh-spice-bugs, sardella, sherold, srevivo, tjay, tlestach, tmraz, tsanders, ykaul, ylavi
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2017-06-26 02:41:30 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:	1456764, 1456765, 1456766
Bug Blocks:	1456767

Description Adam Mariš 2017-05-30 10:19:00 UTC

Two errors in the "asn1_find_node()" function (lib/parser_aux.c) within GnuTLS libtasn1 version 4.10 can be exploited to cause a stacked-based buffer overflow by tricking a user into processing a specially crafted assignments file via the e.g. asn1Coding utility.

Upstream patch:

https://git.savannah.gnu.org/gitweb/?p=libtasn1.git;a=commit;h=5520704d075802df25ce4ffccc010ba1641bd484

Comment 1 Adam Mariš 2017-05-30 10:19:47 UTC

Created libtasn1 tracking bugs for this issue:

Affects: fedora-all [bug 1456765]


Created mingw-libtasn1 tracking bugs for this issue:

Affects: epel-7 [bug 1456766]
Affects: fedora-all [bug 1456764]

Comment 2 Doran Moppert 2017-06-26 02:38:56 UTC

This is Secunia SA76125.  There is some discussion on the upstream mailing list which supports the assessment that the security consequences here are minimal:  typically the overflowed field is provided as a constant by the developer, or parsed by libtasn1 from a ".asn" file (in which case the parser truncates names more than 64 characters).

https://lists.gnu.org/archive/html/htlp-libtasn1/2017-05/

Comment 3 Doran Moppert 2017-06-26 02:39:11 UTC

Statement:

Red Hat Product Security has rated this issue as having Low 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/.