Bug 1964012 (CVE-2021-28904)

Summary:	CVE-2021-28904 libyang: NULL pointer dereference in ext_get_plugin()
Product:	[Other] Security Response	Reporter:	Guilherme de Almeida Suckevicz <gsuckevi>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	mruprich, tkorbar
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	libyang 1.0.225	Doc Type:	If docs needed, set a value
Doc Text:	A flaw was found in libyang. A NULL pointer dereference in ext_get_plugin function allows a remote attacker to crash an application that uses libyang with user-controlled YANG data. The highest threat from this vulnerability is the service availability.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-10-28 12:28:46 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:	1964013, 1965256, 1965257
Bug Blocks:	1964021

Description Guilherme de Almeida Suckevicz 2021-05-24 14:41:36 UTC

In function ext_get_plugin() in libyang <= v1.0.225, it doesn't check whether the value of revision is NULL. If revision is NULL, the operation of strcmp(revision, ext_plugins[u].revision) will lead to a crash.

Reference:
https://github.com/CESNET/libyang/issues/1451

Comment 1 Guilherme de Almeida Suckevicz 2021-05-24 14:41:54 UTC

Created libyang tracking bugs for this issue:

Affects: fedora-all [bug 1964013]

Comment 2 Riccardo Schirone 2021-05-27 09:39:01 UTC

Upstream patch:
https://github.com/CESNET/libyang/commit/59a0bff1a5a2f0a0eac07e4bf94d4aea9dd3708d