-patched helper.rb to use /etc/ssh/ssh_known_hosts also

lib/ssh/key/helper.rb

@@ -12,17 +12,58 @@ def add_key_file(path, passphrase=nil)
 
   # Add a public key from your known_hosts file
   def add_key_from_host(hostname)
-    hostkey = %x{ssh-keygen -F "#{hostname}"}.split("\n")[1].chomp.split(" ",2)[-1] rescue nil
+    hostkey = SSH::Key::Helper.known_host_key('/etc/ssh/ssh_known_hosts', hostname)
     if hostkey == nil
-      raise SSH::Key::KeyNotFound.new("Could not find host key '#{hostname}' " \
-                                       "in known_hosts (using ssh-keygen -F)")
+      hostkey = SSH::Key::Helper.known_host_key('~/.ssh/known_hosts', hostname)
+      if hostkey == nil
+        SSH::Key::KeyNotFound.new("Could not find host key '#{hostname}' " \
+                                       "in known_hosts file")
+      end
     end
-    @keys << Net::SSH::KeyFactory.load_data_public_key(hostkey)
+    @keys << hostkey
   end
 
   # Add a public key from a ublic key string
   def add_public_key_data(data)
     @logger.info "Adding key from data #{data}"
     @keys << Net::SSH::KeyFactory.load_data_public_key(data)
   end # def add_key_file
+
+  def self.known_host_key(host_file, hostname)
+    @@known_hosts ||= {}
+    keys = @@known_hosts[host_file] ||= read_keys(host_file)
+    keys[hostname]
+  end
+
+  # adapted from Net::SSH::KnownHosts#keys_for(host)
+  def self.read_keys(host_file)
+      keys = {}
+      return keys unless File.readable?(host_file)
+
+      File.open(host_file) do |file|
+        scanner = StringScanner.new("")
+        file.each_line do |line|
+          scanner.string = line
+
+          scanner.skip(/\s*/)
+          next if scanner.match?(/$|#/)
+
+          hostlist = scanner.scan(/\S+/).split(/,/)
+
+          scanner.skip(/\s*/)
+          type = scanner.scan(/\S+/)
+
+          next unless Net::SSH::KnownHosts::SUPPORTED_TYPE.include?(type)
+
+          scanner.skip(/\s*/)
+          blob = scanner.rest.unpack("m*").first
+          key = Net::SSH::Buffer.new(blob).read_key
+
+          # only store first key
+          hostlist.each {|host|  keys[host] ||= key }
+        end
+      end
+
+      keys
+  end
 end; end; end # module SSH::Key::Helper

lib/ssh/key/verifier.rb

@@ -99,6 +99,7 @@ def verify(signatures, original)
 
     inputs.each do |signature|
       identities.each do |identity|
+        next unless identity
         key = [signature, identity]
         results[key] = identity.ssh_do_verify(signature, original)
         @logger.info "Trying key #{identity.to_s.split("\n")[1]}... #{results[key]}"