cli-runopts.c: add BatchMode option

The BatchMode same as PasswordAuthentication=no but it has more priority.
So you can't re-enable the PasswordAuthentication like in:

    dbclient -v -o BatchMode=yes -o PasswordAuthentication=yes example.com

It also disables the interactive confirmation when a host key changed.

Close #224

src/cli-auth.c

@@ -245,7 +245,7 @@ void recv_msg_userauth_failure() {
 			}
 #endif
 #if DROPBEAR_CLI_PASSWORD_AUTH
-			if (cli_opts.password_authentication && strncmp(AUTH_METHOD_PASSWORD, tok,
+			if (!cli_opts.batch_mode && cli_opts.password_authentication && strncmp(AUTH_METHOD_PASSWORD, tok,
 				AUTH_METHOD_PASSWORD_LEN) == 0) {
 				ses.authstate.authtypes |= AUTH_TYPE_PASSWORD;
 			}
@@ -311,7 +311,7 @@ int cli_auth_try() {
 #endif
 
 #if DROPBEAR_CLI_PASSWORD_AUTH
-	if (!finished && cli_opts.password_authentication && (ses.authstate.authtypes & AUTH_TYPE_PASSWORD)) {
+	if (!finished && !cli_opts.batch_mode && cli_opts.password_authentication && (ses.authstate.authtypes & AUTH_TYPE_PASSWORD)) {
 		if (ses.keys->trans.algo_crypt->cipherdesc == NULL) {
 			fprintf(stderr, "Sorry, I won't let you use password auth unencrypted.\n");
 		} else {

src/cli-kex.c

@@ -217,11 +217,16 @@ static void ask_to_confirm(const unsigned char* keyblob, unsigned int keybloblen
 		m_free(fp);
 		return;
 	}
-	fprintf(stderr, "\nHost '%s' is not in the trusted hosts file.\n(%s fingerprint %s)\nDo you want to continue connecting? (y/n) ", 
+
+	fprintf(stderr, "\nHost '%s' is not in the trusted hosts file.\n(%s fingerprint %s)\n",
 			cli_opts.remotehost, 
 			algoname,
 			fp);
 	m_free(fp);
+	if (cli_opts.batch_mode) {
+		dropbear_exit("Didn't validate host key");
+	}
+	fprintf(stderr, "Do you want to continue connecting? (y/n) ");
 
 	tty = fopen(_PATH_TTY, "r");
 	if (tty) {

src/cli-runopts.c

@@ -155,6 +155,7 @@ void cli_getopts(int argc, char ** argv) {
 #endif
 	cli_opts.disable_trivial_auth = 0;
 	cli_opts.password_authentication = 1;
+	cli_opts.batch_mode = 0;
 #if DROPBEAR_CLI_LOCALTCPFWD
 	cli_opts.localfwds = list_new();
 	opts.listen_fwd_all = 0;
@@ -889,6 +890,7 @@ static void add_extendedopt(const char* origstr) {
 
 	if (strcmp(origstr, "help") == 0) {
 		dropbear_log(LOG_INFO, "Available options:\n"
+			"\tBatchMode\n"
 			"\tBindAddress\n"
 			"\tDisableTrivialAuth\n"
 #if DROPBEAR_CLI_ANYTCPFWD
@@ -917,6 +919,11 @@ static void add_extendedopt(const char* origstr) {
 		exit(EXIT_SUCCESS);
 	}
 
+	if (match_extendedopt(&optstr, "BatchMode") == DROPBEAR_SUCCESS) {
+		cli_opts.batch_mode = parse_flag_value(optstr);
+		return;
+	}
+
 	if (match_extendedopt(&optstr, "BindAddress") == DROPBEAR_SUCCESS) {
 		cli_opts.bind_arg = optstr;
 		return;

src/runopts.h

@@ -170,7 +170,10 @@ typedef struct cli_runopts {
 	int exit_on_fwd_failure;
 #endif
 	int disable_trivial_auth;
+	/** Use a password authentication or a key auth only.
+	For a BatchMode it's always -o PasswordAuthentication=no */
 	int password_authentication;
+	int batch_mode;
 #if DROPBEAR_CLI_REMOTETCPFWD
 	m_list * remotefwds;
 #endif