Merge pull request #1894 from LabNConsulting/working/master/vtysh-not-enabled

vtysh: add -u/--user flag to run commands without enable

doc/manpages/vtysh.rst

@@ -53,6 +53,10 @@ OPTIONS available for the vtysh command:
 
    When executing cli that does not invoke a vtysh shell, if an error ocurrs ignore it for purposes of return codes from vtysh.
 
+.. option:: -u, --user
+
+   Run as an unprivileged user. This limits access to non-privileged commands, i.e., the same commands when directly accessing a daemon   before running the enable command. It also provides the same limited security as such direct access.
+
 .. option:: -h, --help
 
    Display a usage message on standard output and exit.

vtysh/vtysh.c

@@ -312,6 +312,13 @@ static int vtysh_execute_func(const char *line, int pager)
 	if (vline == NULL)
 		return CMD_SUCCESS;
 
+	if (user_mode) {
+		if (strncmp("en", vector_slot(vline, 0), 2) == 0) {
+			fprintf(stdout, "%% Command not allowed: enable\n");
+			return CMD_WARNING;
+		}
+	}
+
 	saved_ret = ret = cmd_execute_command(vline, vty, &cmd, 1);
 	saved_node = vty->node;
 
@@ -387,13 +394,13 @@ static int vtysh_execute_func(const char *line, int pager)
 			fprintf(stdout, "Warning...\n");
 		break;
 	case CMD_ERR_AMBIGUOUS:
-		fprintf(stdout, "%% Ambiguous command.\n");
+		fprintf(stdout, "%% Ambiguous command: %s\n", line);
 		break;
 	case CMD_ERR_NO_MATCH:
-		fprintf(stdout, "%% Unknown command.\n");
+		fprintf(stdout, "%% Unknown command: %s\n", line);
 		break;
 	case CMD_ERR_INCOMPLETE:
-		fprintf(stdout, "%% Command incomplete.\n");
+		fprintf(stdout, "%% Command incomplete: %s\n", line);
 		break;
 	case CMD_SUCCESS_DAEMON: {
 		/*

vtysh/vtysh.h

@@ -100,4 +100,6 @@ extern int execute_flag;
 
 extern struct vty *vty;
 
+extern int user_mode;
+
 #endif /* VTYSH_H */

vtysh/vtysh_main.c

@@ -60,6 +60,9 @@ static char history_file[MAXPATHLEN];
 /* Flag for indicate executing child command. */
 int execute_flag = 0;
 
+/* Flag to indicate if in user/unprivileged mode. */
+int user_mode;
+
 /* For sigsetjmp() & siglongjmp(). */
 static sigjmp_buf jmpbuf;
 
@@ -150,6 +153,7 @@ static void usage(int status)
 		       "    --vty_socket         Override vty socket path\n"
 		       "    --config_dir         Override config directory path\n"
 		       "-N  --pathspace          Insert prefix into config & socket paths\n"
+		       "-u  --user               Run as an unprivileged user\n"
 		       "-w, --writeconfig        Write integrated config (frr.conf) and exit\n"
 		       "-h, --help               Display this help and exit\n\n"
 		       "Note that multiple commands may be executed from the command\n"
@@ -180,6 +184,7 @@ struct option longopts[] = {
 	{"mark", no_argument, NULL, 'm'},
 	{"writeconfig", no_argument, NULL, 'w'},
 	{"pathspace", required_argument, NULL, 'N'},
+	{"user", no_argument, NULL, 'u'},
 	{0}};
 
 /* Read a string, and return a pointer to it.  Returns NULL on EOF. */
@@ -310,6 +315,8 @@ int main(int argc, char **argv, char **env)
 	realgid = getgid();
 	suid_off();
 
+	user_mode = 0;		/* may be set in options processing */
+
 	/* Preserve name of myself. */
 	progname = ((p = strrchr(argv[0], '/')) ? ++p : argv[0]);
 
@@ -318,7 +325,8 @@ int main(int argc, char **argv, char **env)
 
 	/* Option handling. */
 	while (1) {
-		opt = getopt_long(argc, argv, "be:c:d:nf:mEhCwN:", longopts, 0);
+		opt = getopt_long(argc, argv, "be:c:d:nf:mEhCwN:u",
+				  longopts, 0);
 
 		if (opt == EOF)
 			break;
@@ -375,6 +383,9 @@ int main(int argc, char **argv, char **env)
 		case 'C':
 			dryrun = 1;
 			break;
+		case 'u':
+			user_mode = 1;
+			break;
 		case 'w':
 			writeconfig = 1;
 			break;
@@ -425,11 +436,13 @@ int main(int argc, char **argv, char **env)
 
 	vty_init_vtysh();
 
+	if (!user_mode) {
 		/* Read vtysh configuration file before connecting to daemons.
 		 * (file may not be readable to calling user in SUID mode) */
 		suid_on();
 		vtysh_read_config(vtysh_config);
 		suid_off();
+	}
 
 	if (markfile) {
 		if (!inputfile) {