Bug 1678661

Summary:	openssh: KexAlgorithms=curve25519-sha256 not compatible with DEFAULT profile
Product:	Red Hat Enterprise Linux 8	Reporter:	Stanislav Zidek <szidek>
Component:	crypto-policies	Assignee:	Tomas Mraz <tmraz>
Status:	CLOSED ERRATA	QA Contact:	Simo Sorce <ssorce>
Severity:	medium	Docs Contact:	Mirek Jahoda <mjahoda>
Priority:	medium
Version:	8.0	CC:	hkario, igkioka, jjelen, lmanasko, mjahoda, nmavrogi, omoris, pasik, ssorce, szidek, tmraz
Target Milestone:	rc	Keywords:	Triaged
Target Release:	8.1
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	crypto-policies-20190613-1.git21ffdc8.el8	Doc Type:	Bug Fix
Doc Text:	.`curve25519-sha256` is now supported by default in OpenSSH Previously, the `curve25519-sha256` SSH key exchange algorithm was missing in the system-wide crypto policies configurations for the OpenSSH client and server even though it was compliant with the default policy level. As a consequence, if a client or a server used `curve25519-sha256` and this algorithm was not supported by the host, the connection might fail. This update of the `crypto-policies` package fixes the bug, and SSH connections no longer fail in the described scenario.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2019-11-05 22:33:24 UTC	Type:	Bug
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:	1682515
Bug Blocks:

Description Stanislav Zidek 2019-02-19 10:44:25 UTC

Description of problem:
curve25519-sha256 is not compatible with DEFAULT profile (and perhaps others)

Version-Release number of selected component (if applicable):
RHEL-8.0.0-20190213.0
# rpm -q crypto-policies openssh
crypto-policies-20181217-5.git9a35207.el8.noarch
openssh-7.8p1-4.el8.x86_64

How reproducible:
always

Steps to Reproduce:
1. ssh -o KexAlgorithms=curve25519-sha256 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no localhost

Actual results:
Unable to negotiate with ::1 port 22: no matching key exchange method found. Their offer: curve25519-sha256,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1

Expected results:
Connects normally.

Additional info:
This is regression against RHEL-7, so we need to at least document it as known issue. Not a blocker material.

Comment 1 Tomas Mraz 2019-02-19 10:58:37 UTC

Mirek, can we document it as known issue in RHEL-8.0?
Do we need a separate bug for the documentation?

Comment 19 Simo Sorce 2019-07-08 16:23:25 UTC

Verify test runs in CI: https://baseos-jenkins.rhev-ci-vms.eng.rdu2.redhat.com/job/ci-openstack/29584//console

[10.0.132.116        ] T:       5 [-ciphers-in-practice-do-not-meet-the-stated] Running
[10.0.132.116        ] 1562575727 [Setup                                      ] PASS Score: 0
[10.0.132.116        ] 1562575728 [Test-available-ciphers                     ] PASS Score: 0
[10.0.132.116        ] 1562575729 [Test-available-macs                        ] PASS Score: 0
[10.0.132.116        ] 1562575730 [KEX-algorithms                             ] PASS Score: 0
[10.0.132.116        ] 1562575731 [Key-types                                  ] PASS Score: 0
[10.0.132.116        ] 1562575732 [Cleanup                                    ] PASS Score: 0
[10.0.132.116        ] T:       5 [-ciphers-in-practice-do-not-meet-the-stated] Completed: PASS

Comment 22 errata-xmlrpc 2019-11-05 22:33:24 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, 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-2019:3644