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Bug 2087121 - ssh-keygen generates RSA keys of less than 2048 bits in FIPS mode
Summary: ssh-keygen generates RSA keys of less than 2048 bits in FIPS mode
Alias: None
Product: Red Hat Enterprise Linux 9
Classification: Red Hat
Component: openssh
Version: 9.0
Hardware: All
OS: Linux
Target Milestone: rc
: ---
Assignee: Dmitry Belyavskiy
QA Contact: Marek Havrila
Jan Fiala
Depends On:
Blocks: 2092504
TreeView+ depends on / blocked
Reported: 2022-05-17 11:25 UTC by Ondrej Moriš
Modified: 2022-11-15 13:18 UTC (History)
6 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
.OpenSSH key generation uses FIPS-compatible interfaces The OpenSSL cryptographic library, which is used by OpenSSH, provides two interfaces: legacy and modern. Previously, OpenSSH used the legacy interface for key generation, which did not comply with Federal Information Processing Standards (FIPS) requirements. With this update, the `ssh-keygen` utility uses the FIPS-compliant API instead of the low-level FIPS-incompatible API. As a result, OpenSSH key generation is FIPS-compliant.
Clone Of:
: 2092504 (view as bug list)
Last Closed: 2022-11-15 11:21:44 UTC
Type: Bug
Target Upstream Version:

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Red Hat Issue Tracker CRYPTO-7254 0 None None None 2022-05-17 12:24:46 UTC
Red Hat Issue Tracker RHELPLAN-122346 0 None None None 2022-05-17 11:42:44 UTC
Red Hat Product Errata RHBA-2022:8375 0 None None None 2022-11-15 11:21:59 UTC

Description Ondrej Moriš 2022-05-17 11:25:53 UTC
Description of problem:

Based on NIST Special Publication 800-131A (Revision 2) the length of the modulus n shall be 2048 bits or more for RSA. This was enforced in RHEL-8 and ssh-keygen refused to generate RSA keys smaller than 2048 bits in FIPS. However, this no longer works in RHEL-9.0. 

Version-Release number of selected component (if applicable):


How reproducible:

100% in FIPS mode

Steps to Reproduce:

1. Enable FIPS mode
   # fips-mode-setup --enable && reboot

2. Generate SSH RSA key of size smaller than 2048 bits.
   # ssh-keygen -b 1024 -t rsa -N '' -f /root/.ssh/id_rsa

Actual results:

Generating public/private rsa key pair.
Your identification has been saved in /root/.ssh/id_rsa
Your public key has been saved in /root/.ssh/id_rsa.pub
The key fingerprint is:
SHA256:VEflCzzZ1uaM85mZn1z3uQakLRcnTJXN6br+rBEfCsc root.lab.eng.bos.redhat.com
The key's randomart image is:
+---[RSA 1024]----+
|          ..o.oo+|
|         . o = +o|
|        .   B = o|
|       .    .O O |
|        S  .+EO.o|
|           oo=+o*|
|            ooo*+|
|             .+.B|
|            .o+B+|

Expected results:

rsa_generate_private_key: the key length might be unsupported by FIPS mode approved key generation method
sshkey_generate failed

Comment 9 Dmitry Belyavskiy 2022-06-30 16:14:02 UTC
We also should use the FIPS friendly method for EC keys.

Comment 18 errata-xmlrpc 2022-11-15 11:21:44 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 (openssh 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.


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