RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.
Bug 2070495 - Unbound fails resolution of any SHA-1 signed domain
Summary: Unbound fails resolution of any SHA-1 signed domain
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 9
Classification: Red Hat
Component: unbound
Version: 9.0
Hardware: Unspecified
OS: Unspecified
high
high
Target Milestone: rc
: ---
Assignee: Petr Menšík
QA Contact: Petr Sklenar
Jan Fiala
URL:
Whiteboard:
Depends On: 2070230 2070923
Blocks: el9_dnssec_sha1 2071543 2135933
TreeView+ depends on / blocked
 
Reported: 2022-03-31 09:42 UTC by Petr Menšík
Modified: 2022-10-18 20:52 UTC (History)
7 users (show)

Fixed In Version: unbound-1.13.1-13.el9_0
Doc Type: Known Issue
Doc Text:
.Both `bind` and `unbound` disable validation of SHA-1-based signatures The `bind` and `unbound` components disable validation support of all RSA/SHA1 (algorithm number 5) and RSASHA1-NSEC3-SHA1 (algorithm number 7) signatures, and the SHA-1 usage for signatures is restricted in the DEFAULT system-wide cryptographic policy. As a result, certain DNSSEC records signed with the SHA-1, RSA/SHA1, and RSASHA1-NSEC3-SHA1 digest algorithms fail to verify in Red Hat Enterprise Linux 9 and the affected domain names become vulnerable. To work around this problem, upgrade to a different signature algorithm, such as RSA/SHA-256 or elliptic curve keys. For more information and a list of top-level domains that are affected and vulnerable, see the link:https://access.redhat.com/solutions/6955455/[DNSSEC records signed with RSASHA1 fail to verify] solution.
Clone Of:
: 2071543 (view as bug list)
Environment:
Last Closed: 2022-05-17 13:59:08 UTC
Type: Bug
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Github NLnetLabs unbound issues 656 0 None open [FR] Smart deprecation of SHA-1 signatures 2022-04-01 10:10:45 UTC
Gitlab redhat/centos-stream/rpms unbound merge_requests 12 0 None None None 2022-03-31 13:10:37 UTC
Red Hat Issue Tracker CRYPTO-3196 0 None None None 2022-03-31 09:42:04 UTC
Red Hat Issue Tracker RHELPLAN-117492 0 None None None 2022-03-31 09:47:52 UTC

Description Petr Menšík 2022-03-31 09:42:04 UTC 
Description of problem:


Version-Release number of selected component (if applicable):
unbound-1.13.1-12.el9.x86_64
openssl-libs-3.0.1-20.el9_0.x86_64


How reproducible:
always

Steps to Reproduce:
1. unbound-host -rD secure.d2a7n3.rootcanary.net
2.
3.

Actual results:
secure.d2a7n3.rootcanary.net has address 145.97.20.20
validation failure <secure.d2a7n3.rootcanary.net. A IN>: keyset not secured by DNSKEY that matches DS from 10.38.5.26 for key d2a7n3.rootcanary.net. while building chain of trust
secure.d2a7n3.rootcanary.net has IPv6 address 2001:610:188:408::20
validation failure <secure.d2a7n3.rootcanary.net. AAAA IN>: key for validation d2a7n3.rootcanary.net. is marked as invalid because of a previous validation failure <secure.d2a7n3.rootcanary.net. A IN>: keyset not secured by DNSKEY that matches DS from 10.38.5.26 for key d2a7n3.rootcanary.net. while building chain of trust
validation failure <secure.d2a7n3.rootcanary.net. MX IN>: key for validation d2a7n3.rootcanary.net. is marked as invalid because of a previous validation failure <secure.d2a7n3.rootcanary.net. A IN>: keyset not secured by DNSKEY that matches DS from 10.38.5.26 for key d2a7n3.rootcanary.net. while building chain of trust



Expected results:
unbound-host -rD secure.d2a7n3.rootcanary.net
secure.d2a7n3.rootcanary.net has address 145.97.20.20
secure.d2a7n3.rootcanary.net has IPv6 address 2001:610:188:408::20


Additional info:
Another example domain is ietf.org
Comment 1 Petr Menšík 2022-03-31 10:30:43 UTC 
Current only workaround is setting crypto-policy to DEFAULT:SHA1, which enables also SHA1 algorithm. Then it passes verification of RSASHA1 (algorithm 5) or NSEC3RSASHA1 (algorithm 7).
Comment 2 Petr Menšík 2022-03-31 10:33:01 UTC 
Of course it affects also unbound daemon running in unbound.service, unbound-host example is given just to extract more simple logs and if possible debugging.
Comment 3 Petr Menšík 2022-03-31 10:56:44 UTC 
It seems there is build time support for disabling sha1. According to ./configure --disable-sha1, it would not disable NSEC3 (which has no alternative to SHA-1), but should avoid SHA-1. That might be used as a template to enable SHA-1 if enabled by policy, but make it insecure if SHA-1 is disabled.
Comment 4 Petr Menšík 2022-03-31 12:31:44 UTC 
Quick and dirty solution would be adding --disable-sha1 flag to unbound build. It would make all SHA-1 domains insecure, but resolution should still work also on affected domains, regardless crypto-policy setting.
Comment 11 Petr Menšík 2022-04-01 10:10:45 UTC 
Create issue [1] on upstream to notify them about or problem and desire how it should be solved in ideal way. That would need more work and maybe not small changes to used validator logic. So for emergency fix we would disable validation of all SHA-1 DNSSEC signatures, but later we would like to enable its validation depending on dnssec-policy mode.

1. https://github.com/NLnetLabs/unbound/issues/656
Comment 25 Marcel Härri 2022-04-08 11:40:26 UTC 
I can confirm that the builds from this MR https://gitlab.com/redhat/centos-stream/rpms/unbound/-/merge_requests/12 re-enables the resolution of domains such as paypal.com
Comment 27 errata-xmlrpc 2022-05-17 13:59:08 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 (new packages: unbound), 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/RHBA-2022:2630
Note You need to log in before you can comment on or make changes to this bug.