From nobody Wed Mar 19 21:20:40 2025 X-Original-To: freebsd-security@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4ZJ1pX1zKhz5qjX6 for ; Wed, 19 Mar 2025 21:20:52 +0000 (UTC) (envelope-from crest@rlwinm.de) Received: from mail.rlwinm.de (mail.rlwinm.de [IPv6:2a01:4f8:171:f902::5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4ZJ1pV6sZsz3TP0 for ; Wed, 19 Mar 2025 21:20:50 +0000 (UTC) (envelope-from crest@rlwinm.de) Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=pass (mx1.freebsd.org: domain of crest@rlwinm.de designates 2a01:4f8:171:f902::5 as permitted sender) smtp.mailfrom=crest@rlwinm.de Received: from [IPV6:2001:9e8:957:c200:70c1:4d22:5c7a:16fc] (unknown [IPv6:2001:9e8:957:c200:70c1:4d22:5c7a:16fc]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1) server-digest SHA384) (No client certificate requested) by mail.rlwinm.de (Postfix) with ESMTPSA id D8D37C632 for ; Wed, 19 Mar 2025 21:20:41 +0000 (UTC) Message-ID: <76933d66-eff5-4d43-a7a6-98a153e71d77@rlwinm.de> Date: Wed, 19 Mar 2025 22:20:40 +0100 List-Id: Security issues List-Archive: https://lists.freebsd.org/archives/freebsd-security List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: freebsd-security@freebsd.org Sender: owner-freebsd-security@FreeBSD.org MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: Heads-up: DSA key support being removed from OpenSSH To: freebsd-security@freebsd.org References: Content-Language: en-US From: Jan Bramkamp In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spamd-Result: default: False [0.71 / 15.00]; NEURAL_SPAM_LONG(0.95)[0.947]; NEURAL_SPAM_MEDIUM(0.84)[0.838]; NEURAL_HAM_SHORT(-0.77)[-0.772]; R_SPF_ALLOW(-0.20)[+mx]; MIME_GOOD(-0.10)[text/plain]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCPT_COUNT_ONE(0.00)[1]; ASN(0.00)[asn:24940, ipnet:2a01:4f8::/32, country:DE]; MIME_TRACE(0.00)[0:+]; RCVD_COUNT_ONE(0.00)[1]; MID_RHS_MATCH_FROM(0.00)[]; R_DKIM_NA(0.00)[]; MLMMJ_DEST(0.00)[freebsd-security@freebsd.org]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; ARC_NA(0.00)[]; TO_DN_NONE(0.00)[]; PREVIOUSLY_DELIVERED(0.00)[freebsd-security@freebsd.org]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DMARC_NA(0.00)[rlwinm.de]; RCVD_TLS_ALL(0.00)[] X-Rspamd-Queue-Id: 4ZJ1pV6sZsz3TP0 X-Spamd-Bar: / On 10.02.25 17:57, Ed Maste wrote: > Upstream OpenSSH has been working on deprecating DSA keys for some > time, and I intend to follow suit in FreeBSD. > > From the OpenSSH 9.8p1 release notes: > > === > OpenSSH has disabled DSA keys by default since 2015 but has retained > run-time optional support for them. DSA was the only mandatory-to- > implement algorithm in the SSHv2 RFCs, mostly because alternative > algorithms were encumbered by patents when the SSHv2 protocol was > specified. > > This has not been the case for decades at this point and better > algorithms are well supported by all actively-maintained SSH > implementations. We do not consider the costs of maintaining DSA > in OpenSSH to be justified and hope that removing it from OpenSSH > can accelerate its wider deprecation in supporting cryptography > libraries. > > This release, and its deactivation of DSA by default at compile-time, > marks the second step in our timeline to finally deprecate DSA. The > final step of removing DSA support entirely is planned for the first > OpenSSH release of 2025. > === > > As part of the update to OpenSSH 9.8p1 I intend to disable DSA key > support at compile time. I intend to make this change in main only, > leaving DSA key support enabled in stable/14 and stable/13. > > The change is a trivial update in config.h -- https://reviews.freebsd.org/D48910 As long as it's "only" a compile-time option away for FreeBSD to enable this flawed cipher I would like to have it compiled in by default so it doesn't require installing SSH from ports to connect to some stupid old router/switch/UPS/whatever over SSH. As long as it won't negotiate that cipher with the default configuration that's safe enough for my needs. TL;DR: Please keep it enabled it at compile-time, but configured disabled. FreeBSD shouldn't require recompiling the base system to connect to older embedded devices.