Bug 2028468 (CVE-2020-19861)

Summary:	CVE-2020-19861 ldns: Heap out-of-bound read vulnerability in ldns_nsec3_salt_data function
Product:	[Other] Security Response	Reporter:	Pedro Sampaio <psampaio>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	paul.wouters, pemensik, rlescak
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:	2021-12-14 07:08:20 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:	2028469
Bug Blocks:	2028476

Description Pedro Sampaio 2021-12-02 12:44:50 UTC

In ldns before 1.8.0 when the zone file is parsed, the function ldns_nsec3_salt_data is too trusted for the length value obtained from the zone file. When the memcpy is copied, the 0xfe - ldns_rdf_size(salt_rdf) byte data can be copied, causing heap information leakage.

References:

https://github.com/NLnetLabs/ldns/blob/d3955248eb409b6af0cc6f33e3d458e7f1f555cf/Changelog
https://github.com/NLnetLabs/ldns/issues/51

Comment 1 Pedro Sampaio 2021-12-02 12:45:05 UTC

Created ldns tracking bugs for this issue:

Affects: fedora-all [bug 2028469]