Bug 1844607

Summary:	OpenSSL will use unsafe FFDH primes with 2048 bit RSA keys
Product:	Red Hat Enterprise Linux 8	Reporter:	Alicja Kario <hkario>
Component:	openssl	Assignee:	Tomas Mraz <tmraz>
Status:	CLOSED ERRATA	QA Contact:	Alicja Kario <hkario>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	8.2	CC:	crypto-team, extras-qa, jorton, tmraz
Target Milestone:	rc	Keywords:	Triaged
Target Release:	8.3
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	openssl-1.1.1g-8.el8	Doc Type:	Bug Fix
Doc Text:	OpenSSL will use safe primes in automatically selected DH parameters Previous versions of OpenSSL configured to automatically select Diffie-Hellman parameters in Transport Layer Security (TLS) connection would use group 22 and group 23 from RFC 5114 when configured with 1024 bit or 2048 bit RSA keys. As those groups use primes with known small subgroups, some implementations may reject them (like OpenSSL from RHEL 8.3 working in FIPS mode). This change makes OpenSSL select known safe primes defined in RFC 2409 and RFC 3526.	Story Points:	---
Clone Of:	1844575	Environment:
Last Closed:	2020-11-04 01:54:39 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:	1844575
Bug Blocks:

Description Alicja Kario 2020-06-05 18:35:21 UTC

Description of problem:
When openssl s_server is configured with 2048 bit RSA keys and a DHE cipher is negotiated, it will use the RFC5114 group 23.

Version-Release number of selected component (if applicable):
openssl-1.1.1c-15.el8_2.x86_64

How reproducible:
always

Steps to Reproduce:
1. generate 2048 bit keys
2. connect client to server, force negotiation of DHE ciphers

Actual results:
Server proposes RFC 5114 group 23 in ServerKeyExchange message

Expected results:
Server should select one of the parameters that use safe primes, from either RFC 3526 or RFC 7919


Additional info:

Comment 7 errata-xmlrpc 2020-11-04 01:54:39 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 (Low: openssl 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-2020:4514