op-mode: T5653: command to display SSH server public key fingerprints

op-mode-definitions/show-ssh.xml.in

@@ -0,0 +1,28 @@
+<?xml version="1.0"?>
+<interfaceDefinition>
+  <node name="show">
+    <children>
+      <node name="ssh">
+        <properties>
+          <help>Show SSH server information</help>
+        </properties>
+        <children>
+          <node name="fingerprints">
+            <properties>
+              <help>Show SSH server public key fingerprints</help>
+            </properties>
+            <command>${vyos_op_scripts_dir}/show-ssh-fingerprints.py</command>
+            <children>
+              <node name="ascii">
+                <properties>
+                  <help>Show visual ASCII art representation of the public key</help>
+                </properties>
+                <command>${vyos_op_scripts_dir}/show-ssh-fingerprints.py --ascii</command>
+              </node>
+            </children>
+          </node>
+        </children>
+      </node>
+    </children>
+  </node>
+</interfaceDefinition>

src/op_mode/show-ssh-fingerprints.py

@@ -0,0 +1,49 @@
+#!/usr/bin/env python3
+#
+# Copyright 2017-2023 VyOS maintainers and contributors <[email protected]>
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library.  If not, see <http://www.gnu.org/licenses/>.
+
+import sys
+import glob
+import argparse
+from vyos.utils.process import cmd
+
+# Parse command line
+parser = argparse.ArgumentParser()
+parser.add_argument("--ascii", help="Show visual ASCII art representation of the public key", action="store_true")
+args = parser.parse_args()
+
+# Get list of server public keys
+publickeys = glob.glob("/etc/ssh/*.pub")
+
+if publickeys:
+    print("SSH server public key fingerprints:\n", flush=True)
+    for keyfile in publickeys:
+        if args.ascii:
+            try:
+                print(cmd("ssh-keygen -l -v -E sha256 -f " + keyfile) + "\n", flush=True)
+            # Ignore invalid public keys
+            except:
+                pass
+        else:
+            try:
+                print(cmd("ssh-keygen -l -E sha256 -f " + keyfile) + "\n", flush=True)
+            # Ignore invalid public keys
+            except:
+                pass
+else:
+    print("No SSH server public keys are found.", flush=True)
+
+sys.exit(0)