Merge pull request #275 from hallyn/2020-08-27/test-su

Add tests on top of #254

src/su.c

@@ -55,7 +55,6 @@
 
 #ident "$Id$"
 
-#include <getopt.h>
 #include <grp.h>
 #include <pwd.h>
 #include <signal.h>
@@ -91,10 +90,12 @@ static bool caller_on_console = false;
 static /*@only@*/char *caller_pass;
 #endif
 #endif				/* !USE_PAM */
-static bool doshell = false;
+static bool do_interactive_shell = false;
 static bool fakelogin = false;
 static /*@observer@*/const char *shellstr;
 static /*@null@*/char *command = NULL;
+static /*@null@*/char *exec_command = NULL;
+static int optidx;
 
 
 /* not needed by sulog.c anymore */
@@ -327,11 +328,11 @@ static void prepare_pam_close_session (void)
 		if (   (sigaddset (&ourset, SIGTERM) != 0)
 		    || (sigaddset (&ourset, SIGALRM) != 0)
 		    || (sigaction (SIGTERM, &action, NULL) != 0)
-		    || (   !doshell /* handle SIGINT (Ctrl-C), SIGQUIT
-		                     * (Ctrl-\), and SIGTSTP (Ctrl-Z)
-		                     * since the child will not control
-		                     * the tty.
-		                     */
+		    || (!do_interactive_shell /* handle SIGINT (Ctrl-C), SIGQUIT
+		                               * (Ctrl-\), and SIGTSTP (Ctrl-Z)
+		                               * since the child will not control
+		                               * the tty.
+		                               */
 		        && (   (sigaddset (&ourset, SIGINT)  != 0)
 		            || (sigaddset (&ourset, SIGQUIT) != 0)
 		            || (sigaddset (&ourset, SIGTSTP) != 0)
@@ -440,12 +441,14 @@ static void usage (int status)
 	         "\n"
 	         "Options:\n"
 	         "  -c, --command COMMAND         pass COMMAND to the invoked shell\n"
+	         "  -e, --exec PATH               run PATH without shell, follow -- with args\n"
 	         "  -h, --help                    display this help message and exit\n"
 	         "  -, -l, --login                make the shell a login shell\n"
 	         "  -m, -p,\n"
 	         "  --preserve-environment        do not reset environment variables, and\n"
 	         "                                keep the same shell\n"
 	         "  -s, --shell SHELL             use SHELL instead of the default in passwd\n"
+	         "  --                            pass all subsequent arguments on as-is\n"
 	         "\n"
 	         "If no username is given, assume root.\n"), (E_SUCCESS != status) ? stderr : stdout);
 	exit (status);
@@ -760,6 +763,48 @@ static void save_caller_context (char **argv)
 	pw_free (pw);
 }
 
+/*
+ * flags_match - test arg against flag candidates
+ */
+static bool flags_match(const char *arg, const char *a, const char *b, const char *c)
+{
+	return	(a != NULL && strcmp (arg, a) == 0) ||
+		(b != NULL && strcmp (arg, b) == 0) ||
+		(c != NULL && strcmp (arg, c) == 0);
+}
+
+/* is_flag_like - test if arg resembles a flag
+ *
+ *	lone "--" and bare leading-hyphen-less words are not flag-like,
+ *	everything else is considered a probable flag.
+ */
+static bool is_flag_like(const char *arg)
+{
+	if (arg[0] != '-')
+		return false;
+
+	if (strcmp (arg, "--") == 0)
+		return false;
+
+	return true;
+}
+
+static void flag_arg_required(const char *arg)
+{
+	fprintf (stderr,
+	         _("%s: option \'%s\' requires an argument\n"),
+		 Prog, arg);
+	usage (E_USAGE);
+}
+
+static void flag_unknown(const char *arg)
+{
+	fprintf (stderr,
+	         _("%s: unrecognized option \'%s\'\n"),
+		 Prog, arg);
+	usage (E_BAD_ARG);
+}
+
 /*
  * process_flags - Process the command line arguments
  *
@@ -769,51 +814,58 @@ static void save_caller_context (char **argv)
  */
 static void process_flags (int argc, char **argv)
 {
-	int c;
-	static struct option long_options[] = {
-		{"command",              required_argument, NULL, 'c'},
-		{"help",                 no_argument,       NULL, 'h'},
-		{"login",                no_argument,       NULL, 'l'},
-		{"preserve-environment", no_argument,       NULL, 'p'},
-		{"shell",                required_argument, NULL, 's'},
-		{NULL, 0, NULL, '\0'}
-	};
+	for (optidx = 1; optidx < argc; optidx++) {
+		const char *arg = argv[optidx];
 
-	while ((c = getopt_long (argc, argv, "c:hlmps:",
-	                         long_options, NULL)) != -1) {
-		switch (c) {
-		case 'c':
-			command = optarg;
-			break;
-		case 'h':
+		if (flags_match (arg, "--command", "-c", NULL)) {
+			if (optidx == argc - 1) {
+				flag_arg_required (arg);
+			}
+
+			command = argv[++optidx];
+		} else if (flags_match (arg, "--exec", "-e", NULL)) {
+			if (optidx == argc - 1) {
+				flag_arg_required (arg);
+			}
+
+			exec_command = argv[++optidx];
+		} else if (flags_match (arg, "--help", "-h", NULL)) {
 			usage (E_SUCCESS);
-			break;
-		case 'l':
+		} else if (flags_match (arg, "--login", "-l", "-")) {
 			fakelogin = true;
-			break;
-		case 'm':
-		case 'p':
+		} else if (flags_match (arg, "--preserve-environment", "-p", "-m")) {
 			/* This will only have an effect if the target
 			 * user do not have a restricted shell, or if
 			 * su is called by root.
 			 */
 			change_environment = false;
+		} else if (flags_match (arg, "--shell", "-s", NULL)) {
+			if (optidx == argc - 1) {
+				flag_arg_required (arg);
+			}
+
+			shellstr = argv[++optidx];
+		} else if (is_flag_like (arg)) {
+			flag_unknown (arg);
+		} else {
 			break;
-		case 's':
-			shellstr = optarg;
-			break;
-		default:
-			usage (E_USAGE);	/* NOT REACHED */
 		}
 	}
 
-	if ((optind < argc) && (strcmp (argv[optind], "-") == 0)) {
-		fakelogin = true;
-		optind++;
+	if (NULL != exec_command && NULL != command) {
+		fprintf (stderr,
+		         _("%s: COMMAND and PATH are mutually exclusive\n"),
+		         argv[0]);
+		usage (E_USAGE);
 	}
 
-	if (optind < argc) {
-		STRFCPY (name, argv[optind++]);	/* use this login id */
+	if (NULL != exec_command) {
+		command = exec_command;
+	}
+
+	/* if next arg is not "--", treat as USER */
+	if (optidx < argc && strcmp (argv[optidx], "--")) {
+		STRFCPY (name, argv[optidx++]);	/* use this login id */
 	}
 	if ('\0' == name[0]) {		/* use default user */
 		struct passwd *root_pw = getpwnam ("root");
@@ -829,9 +881,14 @@ static void process_flags (int argc, char **argv)
 		}
 	}
 
-	doshell = (argc == optind);	/* any arguments remaining? */
+	/* if more and next arg is "--", skip it and leave rest as-is */
+	if (optidx < argc && strcmp (argv[optidx], "--") == 0) {
+		optidx++;
+	}
+
+	do_interactive_shell = (argc == optidx);	/* any arguments remaining? */
 	if (NULL != command) {
-		doshell = false;
+		do_interactive_shell = false;
 	}
 }
 
@@ -1107,7 +1164,7 @@ int main (int argc, char **argv)
 
 	set_environment (pw);
 
-	if (!doshell) {
+	if (!do_interactive_shell) {
 		/* There is no need for a controlling terminal.
 		 * This avoids the callee to inject commands on
 		 * the caller's tty. */
@@ -1175,10 +1232,10 @@ int main (int argc, char **argv)
 		cp = Basename (shellstr);
 	}
 
-	if (!doshell) {
+	if (!do_interactive_shell) {
 		int err;
 		/* Position argv to the remaining arguments */
-		argv += optind;
+		argv += optidx;
 		if (NULL != command) {
 			argv -= 2;
 			argv[0] = "-c";
@@ -1189,10 +1246,18 @@ int main (int argc, char **argv)
 		 * with the rest of the command line included.
 		 */
 		argv[-1] = cp;
-		execve_shell (shellstr, &argv[-1], environ);
-		err = errno;
-		(void) fprintf (stderr,
-		                _("Cannot execute %s\n"), shellstr);
+
+		if (NULL != exec_command) {
+			(void) execve (command, &argv[1], environ);
+			err = errno;
+			(void) fprintf (stderr,
+					_("Cannot execute \'%s\'\n"), command);
+		} else {
+			execve_shell (shellstr, &argv[-1], environ);
+			err = errno;
+			(void) fprintf (stderr,
+					_("Cannot execute \'%s\'\n"), shellstr);
+		}
 		errno = err;
 	} else {
 		(void) shell (shellstr, cp, environ);