tools/rtrclient: implement ssh password auth

Author: mroethke

tools/rtrclient.1

@@ -24,7 +24,7 @@ rtrclient \- rtr rpki client
 .IR HOST
 .IR PORT
 .IR USERNAME
-.IR PRIVATE_KEY
+(\fIPRIVATE_KEY\fR|\fIPASSWORD\fR)
 [\fIHOST_KEY\fR]
 .SH DESCRIPTION
 \fBrtrclient\fR connects to an RPKI/RTR cache server and prints prefix, origin AS, and router key updates.
@@ -33,7 +33,8 @@ The amount is not limited and different transport types can be mixed arbitrarily
 .LP
 For \fBtcp\fR you must specify the \fIHOST\fR and \fIPORT\fR.
 .LP
-For \fBssh\fR you must specify the \fIHOST\fR, \fIPORT\fR, \fIUSERNAME\fR and a file containing the \fIPRIVATE_KEY\fR.
+For \fBssh\fR you must specify the \fIHOST\fR, \fIPORT\fR, \fIUSERNAME\fR and a file containing the \fIPRIVATE_KEY\fR or a \fIPASSWORD\fR.
+By default the rtrclient will try to guess which of the two was entered. If you want to explicitly specify this see \fB-w\fR and \fB-s\fR.
 You may specify a file containing a list of \fIHOST_KEY\fRs, in the well known
 .B SSH_KNOWN_HOSTS
 file format. See \fIsshd(8)\fR for details.
@@ -53,6 +54,7 @@ Print information about router key updates
 \fB-p\fR
 .RS 4
 Print information about prefix and origin AS updates
+.RE
 \fB-s\fR
 .RS 4
 Print information about connection status updates
@@ -72,6 +74,14 @@ Print available templates and exit. Prints specified templated, when used with -
 \fB-o\fR
 .RS 4
 Output file for export
+.RE
+\fB-w\fR
+.RS 4
+force ssh authentication information to be interpreted as a password
+.RE
+\fB-s\fR
+.RS 4
+force ssh authentication information to be interpreted as a private key
 .SH TEMPLATES
 Templates can be used to export ROA information in a custom format. They are written in the \fBmustache\fR(\fIhttps://mustache.github.io/\fR) templating language.
 

tools/rtrclient.c

@@ -29,6 +29,20 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#ifdef RTRLIB_HAVE_LIBSSH
+// constants for utf8 validation
+static const uint8_t UTF8_ONE_BYTE_PREFIX = 0b00000000;
+static const uint8_t UTF8_ONE_BYTE_MASK = 0b10000000;
+static const uint8_t UTF8_TWO_BYTE_PREFIX = 0b11000000;
+static const uint8_t UTF8_TWO_BYTE_MASK = 0b11100000;
+static const uint8_t UTF8_THREE_BYTE_PREFIX = 0b11100000;
+static const uint8_t UTF8_THREE_BYTE_MASK = 0b11110000;
+static const uint8_t UTF8_FOUR_BYTE_PREFIX = 0b11110000;
+static const uint8_t UTF8_FOUR_BYTE_MASK = 0b11111000;
+static const uint8_t UTF8_SUBSEQUENT_BYTE_PREFIX = 0b10000000;
+static const uint8_t UTF8_SUBSEQUENT_BYTE_MASK = 0b11000000;
+#endif
+
 __attribute__((format(printf, 1, 2), noreturn)) static void print_error_exit(const char *fmt, ...);
 
 static bool is_readable_file(const char *str);
@@ -53,6 +67,9 @@ struct socket_config {
 	char *ssh_username;
 	char *ssh_private_key;
 	char *ssh_host_key;
+	char *ssh_password;
+	bool force_password;
+	bool force_key;
 #endif
 };
 
@@ -230,6 +247,44 @@ static bool is_readable_file(const char *str)
 	return is_file(str);
 }
 
+#ifdef RTRLIB_HAVE_LIBSSH
+static bool is_utf8(const char *str)
+{
+	size_t len = strlen(str);
+	size_t i = 0;
+
+	while (i < len) {
+		// check if current byte is a single utf8 char
+		if ((str[i] & UTF8_ONE_BYTE_MASK) == UTF8_ONE_BYTE_PREFIX) {
+			i += 1;
+
+		// check if current byte is the start of a two byte utf8 char and validate subsequent bytes
+		} else if ((str[i] & UTF8_TWO_BYTE_MASK) == UTF8_TWO_BYTE_PREFIX && i + 1 < len &&
+			   (str[i + 1] & UTF8_SUBSEQUENT_BYTE_MASK) == UTF8_SUBSEQUENT_BYTE_PREFIX) {
+			i += 2;
+
+		// check if current byte is the start of a three byte utf8 char and validate subsequent bytes
+		} else if ((str[i] & UTF8_THREE_BYTE_MASK) == UTF8_THREE_BYTE_PREFIX && i + 2 < len &&
+			   (str[i + 1] & UTF8_SUBSEQUENT_BYTE_MASK) == UTF8_SUBSEQUENT_BYTE_PREFIX &&
+			   (str[i + 2] & UTF8_SUBSEQUENT_BYTE_MASK) == UTF8_SUBSEQUENT_BYTE_PREFIX) {
+			i += 3;
+
+		// check if current byte is the start of a four byte utf8 char and validate subsequent bytes
+		} else if ((str[i] & UTF8_FOUR_BYTE_MASK) == UTF8_FOUR_BYTE_PREFIX && i + 3 < len &&
+			   (str[i + 1] & UTF8_SUBSEQUENT_BYTE_MASK) == UTF8_SUBSEQUENT_BYTE_PREFIX &&
+			   (str[i + 2] & UTF8_SUBSEQUENT_BYTE_MASK) == UTF8_SUBSEQUENT_BYTE_PREFIX &&
+			   (str[i + 3] & UTF8_SUBSEQUENT_BYTE_MASK) == UTF8_SUBSEQUENT_BYTE_PREFIX) {
+			i += 4;
+
+		// if none of the conditions matched. The string contains at least one byte that is not valid utf8
+		} else {
+			return false;
+		}
+	}
+	return true;
+}
+#endif
+
 struct exporter_state {
 	bool roa_section;
 	tommy_count_t current_roa;
@@ -359,11 +414,16 @@ static void print_usage(char **argv)
 	printf("\nSocket:\n");
 	printf(" tcp [-hpkb bindaddr] <host> <port>\n");
 #ifdef RTRLIB_HAVE_LIBSSH
-	printf(" ssh [-hpkb bindaddr] <host> <port> <username> <private_key> [<host_key>]\n");
+	printf(" ssh [-hpkb bindaddr] <host> <port> <username> (<private_key> | <password>) [<host_key>]\n");
 #endif
 	printf("\nOptions:\n");
 	printf("-b  bindaddr Hostnamne or IP address to connect from\n\n");
 
+#ifdef RTRLIB_HAVE_LIBSSH
+	printf("-w  force ssh authentication information to be interpreted as a password\n");
+	printf("-r  force ssh authentication information to be interpreted as a private key\n\n");
+#endif
+
 	printf("-k  Print information about SPKI updates.\n");
 	printf("-p  Print information about PFX updates.\n");
 	printf("-s  Print information about connection status updates.\n\n");
@@ -536,7 +596,7 @@ static void parse_socket_opts(int argc, char **argv, struct socket_config *confi
 {
 	int opt;
 
-	while ((opt = getopt(argc, argv, "+kphb:")) != -1) {
+	while ((opt = getopt(argc, argv, "+kphwrb:")) != -1) {
 		switch (opt) {
 		case 'k':
 			activate_spki_update_cb = true;
@@ -552,6 +612,22 @@ static void parse_socket_opts(int argc, char **argv, struct socket_config *confi
 			config->bindaddr = optarg;
 			break;
 
+#ifdef RTRLIB_HAVE_LIBSSH
+		case 'w':
+			if (config->force_key)
+				print_error_exit("-w and -r are mutually exclusive");
+
+			config->force_password = true;
+			break;
+
+		case 'r':
+			if (config->force_password)
+				print_error_exit("-w and -r are mutually exclusive");
+
+			config->force_key = true;
+			break;
+#endif
+
 		default:
 			print_usage(argv);
 			exit(EXIT_FAILURE);
@@ -590,7 +666,7 @@ static int parse_cli(int argc, char **argv)
 		CLI_PARSE_STATE_SOCKET_SSH_HOST,
 		CLI_PARSE_STATE_SOCKET_SSH_PORT,
 		CLI_PARSE_STATE_SOCKET_SSH_USERNAME,
-		CLI_PARSE_STATE_SOCKET_SSH_PRIVATE_KEY,
+		CLI_PARSE_STATE_SOCKET_SSH_PRIVATE_KEY_PASSWORD,
 		CLI_PARSE_STATE_SOCKET_SSH_HOST_KEY,
 #endif
 		CLI_PARSE_STATE_END,
@@ -714,15 +790,36 @@ static int parse_cli(int argc, char **argv)
 		case CLI_PARSE_STATE_SOCKET_SSH_USERNAME:
 			current_config->ssh_username = argv[optind++];
 
-			state = CLI_PARSE_STATE_SOCKET_SSH_PRIVATE_KEY;
+			state = CLI_PARSE_STATE_SOCKET_SSH_PRIVATE_KEY_PASSWORD;
 			break;
 
-		case CLI_PARSE_STATE_SOCKET_SSH_PRIVATE_KEY:
-			if (!is_readable_file(argv[optind]))
+		case CLI_PARSE_STATE_SOCKET_SSH_PRIVATE_KEY_PASSWORD:
+			if (current_config->force_key && !is_readable_file(argv[optind])) {
 				print_error_exit("\"%s\" is not a readable file\n", argv[optind]);
 
-			current_config->ssh_private_key = argv[optind++];
+			} else if (!current_config->force_password && !current_config->force_key &&
+				   is_readable_file(argv[optind])) {
+				current_config->ssh_private_key = argv[optind];
 
+			} else if (!current_config->force_password && is_utf8(argv[optind])) {
+				fprintf(stderr, "\"%s\" does not seem to be a file. Trying password authentication.\n",
+					argv[optind]);
+				fprintf(stderr, "Use -r to force key authentication or -w to silence this warning");
+				current_config->ssh_password = argv[optind];
+
+			} else if (current_config->force_password && !is_utf8(argv[optind])) {
+				print_error_exit("\"%s\" is not a valid utf8 string", argv[optind]);
+
+			} else if (current_config->force_password && !current_config->force_key &&
+				   is_utf8(argv[optind])) {
+				current_config->ssh_password = argv[optind];
+
+			} else {
+				print_error_exit("\"%s\" is neither a readable file nor a valid utf8 string",
+						 argv[optind]);
+			}
+
+			++optind;
 			state = CLI_PARSE_STATE_SOCKET_SSH_HOST_KEY;
 			break;
 
@@ -778,6 +875,7 @@ static void init_sockets(void)
 			ssh_config.username = config->ssh_username;
 			ssh_config.client_privkey_path = config->ssh_private_key;
 			ssh_config.server_hostkey_path = config->ssh_host_key;
+			ssh_config.password = config->ssh_password;
 
 			tr_ssh_init(&ssh_config, &config->tr_socket);
 			config->socket.tr_socket = &config->tr_socket;