1 files changed, 62 insertions, 0 deletions
diff --git a/Propellor/Property/Ssh.hs b/Propellor/Property/Ssh.hs
new file mode 100644
index 00000000..59845f8f
--- /dev/null
+++ b/Propellor/Property/Ssh.hs
@@ -0,0 +1,62 @@
+module Propellor.Property.Ssh (
+	setSshdConfig,
+	permitRootLogin,
+	passwordAuthentication,
+	hasAuthorizedKeys,
+	restartSshd,
+	uniqueHostKeys
+) where
+
+import Propellor
+import qualified Propellor.Property.File as File
+import Propellor.Property.User
+import Utility.SafeCommand
+
+sshBool :: Bool -> String
+sshBool True = "yes"
+sshBool False = "no"
+
+sshdConfig :: FilePath
+sshdConfig = "/etc/ssh/sshd_config"
+
+setSshdConfig :: String -> Bool -> Property
+setSshdConfig setting allowed = combineProperties "sshd config"
+	[ sshdConfig `File.lacksLine` (sshline $ not allowed)
+	, sshdConfig `File.containsLine` (sshline allowed)
+	]
+	`onChange` restartSshd
+	`describe` unwords [ "ssh config:", setting, sshBool allowed ]
+  where
+	sshline v = setting ++ " " ++ sshBool v
+
+permitRootLogin :: Bool -> Property
+permitRootLogin = setSshdConfig "PermitRootLogin"
+
+passwordAuthentication :: Bool -> Property
+passwordAuthentication = setSshdConfig "PasswordAuthentication"
+
+hasAuthorizedKeys :: UserName -> IO Bool
+hasAuthorizedKeys = go <=< homedir
+  where
+	go Nothing = return False
+	go (Just home) = not . null <$> catchDefaultIO ""
+		(readFile $ home </> ".ssh" </> "authorized_keys")
+
+restartSshd :: Property
+restartSshd = cmdProperty "service" ["ssh", "restart"]
+
+-- | Blows away existing host keys and make new ones.
+-- Useful for systems installed from an image that might reuse host keys.
+-- A flag file is used to only ever do this once.
+uniqueHostKeys :: Property
+uniqueHostKeys = flagFile prop "/etc/ssh/.unique_host_keys"
+	`onChange` restartSshd
+  where
+	prop = Property "ssh unique host keys" $ do
+		void $ liftIO $ boolSystem "sh"
+			[ Param "-c"
+			, Param "rm -f /etc/ssh/ssh_host_*"
+			]
+		ensureProperty $
+			cmdProperty "/var/lib/dpkg/info/openssh-server.postinst"
+				["configure"]