SSH: Add sntrup761x25519-sha512@openssh.com key exchange to configurations

This algorithm was introduced in OpenSSH 9.0p1; also, align the
curve25519-sha256* key exchanges to keep things tidy.

Signed-off-by: Peter Müller <peter.mueller@ipfire.org>

diff --git a/config/ssh/ssh_config b/config/ssh/ssh_config
index 2e2ee60c39e7f5ba68ea955077b046add2dbaa41..ee0954d5c92a4807ddf38b1b2cd2c9e4c7867c64 100644 (file)
--- a/config/ssh/ssh_config
+++ b/config/ssh/ssh_config
@@ -9,7 +9,7 @@ Host *
         UseRoaming no
 
         # Only use secure crypto algorithms
-        KexAlgorithms curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256
+        KexAlgorithms sntrup761x25519-sha512@openssh.com,curve25519-sha256,curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256
         Ciphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@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
 

diff --git a/config/ssh/sshd_config b/config/ssh/sshd_config
index bea5cee5340e3841c6ade17232a814ade8b8c95b..4565565403caf08c49f01a1b2f8e18c68ed206b2 100644 (file)
--- a/config/ssh/sshd_config
+++ b/config/ssh/sshd_config
@@ -19,9 +19,8 @@ LoginGraceTime 30s
 # Limit maximum instanctes to prevent DoS
 MaxStartups 5
 
-# Only allow safe crypto algorithms (may break some _very_ outdated clients)
-# See also: https://stribika.github.io/2015/01/04/secure-secure-shell.html
-KexAlgorithms curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256
+# Only allow safe crypto algorithms
+KexAlgorithms sntrup761x25519-sha512@openssh.com,curve25519-sha256,curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256
 Ciphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@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