From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail02.haj.ipfire.org (localhost [IPv6:::1]) by mail02.haj.ipfire.org (Postfix) with ESMTP id 4cZcKw29N6z2xSN for ; Sun, 28 Sep 2025 21:05:40 +0000 (UTC) Received: from mail01.ipfire.org (mail01.haj.ipfire.org [IPv6:2001:678:b28::25]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature ECDSA (secp384r1) server-digest SHA384 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mail01.haj.ipfire.org", Issuer "R13" (verified OK)) by mail02.haj.ipfire.org (Postfix) with ESMTPS id 4cZcKr6kHmz2xP7 for ; Sun, 28 Sep 2025 21:05:36 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) (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) (No client certificate requested) by mail01.ipfire.org (Postfix) with ESMTPSA id 4cZcKn2r6Hz3X8 for ; Sun, 28 Sep 2025 21:05:33 +0000 (UTC) DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=ipfire.org; s=202003ed25519; t=1759093534; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=X/0pFEr+sGtcvge2NBePhBB50ShBGdKgQR5DnPUt/vA=; b=IsryebmKVySUYmrsz6kU5XlPKCb3hxDpio9E1KMi5J2/DYExdVKb4UusCQuOv9YtuTKpCx R3ewNvIcVI8/LkCg== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ipfire.org; s=202003rsa; t=1759093534; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=X/0pFEr+sGtcvge2NBePhBB50ShBGdKgQR5DnPUt/vA=; b=k1cYbSpJVaViUnbqJzgQn6qWQ3Mga9DqEWDyC4eMa3Jl8qgkiJ/ZhZVFOqeeyTPS/xzTDe +jnkotHpuonwZ4igpLEyW743AmnAKQfeZhjWQZtPsVgDeDeO0sNGdI0Int2ZQyiIVWW8X2 A4jxjRXq+053ujqWhbpoZ+6g+XhnvL0/a2YsVCTjuwx1KF7M63ZGkF17p6CvoGQLVEktsW Wd6kDqROloM8O2ShQToIGB6YQBsCeGaJl6quyqgi/kgtHLOydsOA7I+tGYY7EEXQskxnwG +CgOPAqeBoH5gEKJLW16YU6eGQXBPjeNBq3wkNaUOYRbu04ss82ZYBFE/3HJww== Message-ID: <5d3b4fdd-fe49-4997-b00c-c2fd723f0e4a@ipfire.org> Date: Sun, 28 Sep 2025 21:05:00 +0000 Precedence: list List-Id: List-Subscribe: , List-Unsubscribe: , List-Post: List-Help: Sender: Mail-Followup-To: MIME-Version: 1.0 To: "IPFire: Development" From: =?UTF-8?Q?Peter_M=C3=BCller?= Subject: [PATCH 1/3] OpenSSH: Prefer AES-GCM ciphers over AES-CTR Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This reflects the following change made upstream in OpenSSH 9.9: * ssh(1): prefer AES-GCM to AES-CTR mode when selecting a cipher for the connection. The default cipher preference list is now Chacha20/Poly1305, AES-GCM (128/256) followed by AES-CTR (128/192/256). However, we keep preferring AES-GCM over Chacha/Poly, as hardware acceleration often grants the former a better performance, while there is no security advance of Chacha/Poly usage over 256 bit AES-GCM. Signed-off-by: Peter Müller --- config/ssh/ssh_config | 2 +- config/ssh/sshd_config | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/config/ssh/ssh_config b/config/ssh/ssh_config index d5f63f315..a248001ff 100644 --- a/config/ssh/ssh_config +++ b/config/ssh/ssh_config @@ -10,7 +10,7 @@ Host * # Only use secure crypto algorithms KexAlgorithms sntrup761x25519-sha512,sntrup761x25519-sha512@openssh.com,mlkem768x25519-sha256,curve25519-sha256,curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256 - Ciphers aes256-gcm@openssh.com,aes256-ctr,chacha20-poly1305@openssh.com,aes192-ctr,aes128-gcm@openssh.com,aes128-ctr + Ciphers aes256-gcm@openssh.com,aes128-gcm@openssh.com,chacha20-poly1305@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr MACs hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,umac-128@openssh.com # Always visualise server host keys (helps to identify key based MITM attacks) diff --git a/config/ssh/sshd_config b/config/ssh/sshd_config index 7b687457c..25e5b1838 100644 --- a/config/ssh/sshd_config +++ b/config/ssh/sshd_config @@ -21,7 +21,7 @@ MaxStartups 5 # Only allow safe crypto algorithms KexAlgorithms sntrup761x25519-sha512,sntrup761x25519-sha512@openssh.com,mlkem768x25519-sha256,curve25519-sha256,curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256 -Ciphers aes256-gcm@openssh.com,aes256-ctr,chacha20-poly1305@openssh.com,aes192-ctr,aes128-gcm@openssh.com,aes128-ctr +Ciphers aes256-gcm@openssh.com,aes128-gcm@openssh.com,chacha20-poly1305@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr MACs hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,umac-128@openssh.com # Only allow cryptographically safe SSH host keys (adjust paths if needed) -- 2.51.0