Bug 2071543

Summary:	Unbound fails resolution of any SHA-1 signed domain [rhel-9.1.0]
Product:	Red Hat Enterprise Linux 9	Reporter:	RHEL Program Management Team <pgm-rhel-tools>
Component:	unbound	Assignee:	Petr Menšík <pemensik>
Status:	CLOSED ERRATA	QA Contact:	Petr Sklenar <psklenar>
Severity:	high	Docs Contact:	Jan Fiala <jafiala>
Priority:	high
Version:	9.0	CC:	jafiala, jjelen, omejzlik, pemensik, psklenar, pvlasin
Target Milestone:	rc	Keywords:	Triaged
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	unbound-1.13.1-13.el9	Doc Type:	Bug Fix
Doc Text:	.Unbound no longer validates SHA-1-based RSA signatures Previously, OpenSSL did not validate SHA-1-based RSA signatures in the DEFAULT system-wide cryptographic policy. As a consequence, when Unbound tried to validate such signatures, the error from OpenSSL caused the resolution to fail. With this update, Unbound disables validation support of all RSA/SHA1 (algorithm number 5) and RSASHA1-NSEC3-SHA1 (algorithm number 7) signatures, which resolves the query. Note that this makes the result insecure under all system-wide cryptographic policies.	Story Points:	---
Clone Of:	2070495
Clones:	2135933 (view as bug list)		Environment:
Last Closed:	2022-11-15 10:15:56 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:	2070495, 2087120
Bug Blocks:	2077909, 2135933

Comment 2 Petr Menšík 2022-04-27 10:41:45 UTC

I would like to modify this behaviour in unbound to follow crypto-policy settings. It has to disable SHA-1 validation under DEFAULT crypto-policy, but it should allow secure reply in DEFAULT:SHA1 policy.

Proposal to upstream were offered [1], but it did not trigger any response from them yet. Perhaps they think this is only our internal problem.

1. https://github.com/NLnetLabs/unbound/issues/656

Comment 7 Petr Menšík 2022-08-11 12:01:59 UTC

With a rebase to recent 1.16.2 version, the build should be able to disable validation on DEFAULT policy, but keep it enabled in DEFAULT:SHA1 or LEGACY policies.

Comment 10 Petr Menšík 2022-08-25 18:24:27 UTC

It seems the change I offered to upstream (and which is merged in this version) were not complete. I wanted algorithm 7 signatures to become (secure) when update-crypto-policies --set DEFAULT:SHA1 is used. But if I enable SHA-1 algorithm again, it fails in unittest.

Failing MR 17. Unit tests result has to be reviewed, maybe there is hidden issue. On the first glance resolution becomes secure on DEFAULT:SHA1 policy and insecure on DEFAULT policy, but I think we can postpone this dynamic switching to 9.2. Better to have always insecure SHA-1 signatures than resulting to SERVFAIL bogus results in a few cases.

[1] https://gitlab.com/redhat/centos-stream/rpms/unbound/-/merge_requests/17

Comment 13 errata-xmlrpc 2022-11-15 10:15:56 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (Moderate: unbound security, bug fix, and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2022:8062