Security Enhancements

This patch enhances libStorage security:

* If discovered in '$LIBSTORAGE_PATHS_TLS' the following files
  are automatically loaded:

  * `libstorage.crt`
  * `libstorage.key`
  * `cacerts`

* If `$LIBSTORAGE_PATHS_ETC/known_hosts` exists it is automatically
  loaded unless the property `libstorage.tls.knownHosts` is explicitly
  defined. This is the system's `known_hosts` file.

* If `$HOME/.libstorage/known_hosts` exists it is automatically used
  when TLS security is set to verify peer certificates. This is the
  user's `known_hosts` file.

* The above `known_hosts` files are line-delimited with each line
  following the format: 'HOST ALGORITHM FINGERPRINT'

* The property `libstorage.tls.verifyPeers` is introduced. It's a
  boolean flag that indicates TLS connections should be verified
  against a known list of peer certificate fingerprints in the
  system's and user's `known_hosts` files.

  Enabling this property also sets `libstorage.tls.insecure` to `true`.
  The connection will be encrypted, but the certificate verification is
  disabled and deferred to the peer verification.

* The property `libstorage.tls` can now be set to a simple string value
  of `verifyPeers` to indicate TLS connections should be verified
  against the system's and user's `known_hosts` files.

api/types/types_config.go

@@ -99,6 +99,12 @@ const (
 	// ConfigTLSServerName is a config key.
 	ConfigTLSServerName = ConfigTLS + ".serverName"
 
+	// ConfigTLSKnownHosts is a config key.
+	ConfigTLSKnownHosts = ConfigTLS + ".knownHosts"
+
+	// ConfigTLSVerifyPeers is a config key.
+	ConfigTLSVerifyPeers = ConfigTLS + ".verifyPeers"
+
 	// ConfigTLSClientCertRequired is a config key.
 	ConfigTLSClientCertRequired = ConfigTLS + ".clientCertRequired"
 

api/types/types_paths.go

@@ -109,6 +109,22 @@ const (
 	// LSX is the path to the libStorage executor.
 	LSX
 
+	// DefaultTLSCertFile is the default path to the TLS cert file,
+	// libstorage.crt.
+	DefaultTLSCertFile
+
+	// DefaultTLSKeyFile is the default path to the TLS key file,
+	// libstorage.key.
+	DefaultTLSKeyFile
+
+	// DefaultTLSTrustedRootsFile is the default path to the TLS trusted roots
+	// file, cacerts.
+	DefaultTLSTrustedRootsFile
+
+	// DefaultTLSKnownHosts is the default path to the TLS known hosts file,
+	// known_hosts file.
+	DefaultTLSKnownHosts
+
 	maxFileKey
 )
 
@@ -167,6 +183,10 @@ func (k fileKey) parent() fileKey {
 		return Etc
 	case LSX:
 		return Lib
+	case DefaultTLSCertFile,
+		DefaultTLSKeyFile,
+		DefaultTLSTrustedRootsFile:
+		return TLS
 	default:
 		return Home
 	}
@@ -195,6 +215,14 @@ func (k fileKey) key() string {
 		return "tls"
 	case LSX:
 		return "lsx"
+	case DefaultTLSCertFile:
+		return "crt"
+	case DefaultTLSKeyFile:
+		return "key"
+	case DefaultTLSTrustedRootsFile:
+		return "tca"
+	case DefaultTLSKnownHosts:
+		return "hst"
 	}
 	return ""
 }
@@ -239,6 +267,14 @@ func (k fileKey) defaultVal() string {
 		default:
 			return fmt.Sprintf("lsx-%s", runtime.GOOS)
 		}
+	case DefaultTLSCertFile:
+		return "libstorage.crt"
+	case DefaultTLSKeyFile:
+		return "libstorage.key"
+	case DefaultTLSTrustedRootsFile:
+		return "cacerts"
+	case DefaultTLSKnownHosts:
+		return "known_hosts"
 	}
 	return ""
 }

api/types/types_paths_test.go

@@ -25,6 +25,11 @@ func TestPaths(t *testing.T) {
 	t.Logf("%5[1]s  %[2]s", Home.key(), Home)
 	t.Logf("%5[1]s  %[2]s", Etc.key(), Etc)
 	t.Logf("%5[1]s  %[2]s", TLS.key(), TLS)
+	t.Logf("%5[1]s  %[2]s", DefaultTLSCertFile.key(), DefaultTLSCertFile)
+	t.Logf("%5[1]s  %[2]s", DefaultTLSKeyFile.key(), DefaultTLSKeyFile)
+	t.Logf("%5[1]s  %[2]s",
+		DefaultTLSTrustedRootsFile.key(), DefaultTLSTrustedRootsFile)
+	t.Logf("%5[1]s  %[2]s", DefaultTLSKnownHosts.key(), DefaultTLSKnownHosts)
 	t.Logf("%5[1]s  %[2]s", Lib.key(), Lib)
 	t.Logf("%5[1]s  %[2]s", Log.key(), Log)
 	t.Logf("%5[1]s  %[2]s", Run.key(), Run)

api/types/types_tls.go

@@ -7,6 +7,16 @@ import "crypto/tls"
 type TLSConfig struct {
 	tls.Config
 
+	// VerifyPeers is a flag that indicates whether peer certificates
+	// should be validated against a PeerFingerprint or known hosts files.
+	VerifyPeers bool
+
+	// SysKnownHosts is the path to the system's known_hosts file.
+	SysKnownHosts string
+
+	// UsrKnownHosts is the path to the user's known_hosts file.
+	UsrKnownHosts string
+
 	// PeerFingerprint is the expected SHA256 fingerprint of a peer certificate.
 	PeerFingerprint []byte
 }