X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;ds=sidebyside;f=loginutils%2Fsu.c;h=72dd0f06f0b6a59ed1fd2885177aac8c25af4deb;hb=b8709032a3fb57b3ec536bdf9b92b526ed63b995;hp=e1c1591aa6dab292b9005f476a7eb612877ddd4d;hpb=e13a537795751bee8e2b7fe2b88c75436acd9da0;p=oweals%2Fbusybox.git

diff --git a/loginutils/su.c b/loginutils/su.c
index e1c1591aa..72dd0f06f 100644
--- a/loginutils/su.c
+++ b/loginutils/su.c
@@ -1,65 +1,100 @@
 /* vi: set sw=4 ts=4: */
 /*
- *  Mini su implementation for busybox
+ * Mini su implementation for busybox
  *
- *  Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 
-#include "busybox.h"
+#include "libbb.h"
 #include <syslog.h>
 
+//usage:#define su_trivial_usage
+//usage:       "[OPTIONS] [-] [USER]"
+//usage:#define su_full_usage "\n\n"
+//usage:       "Run shell under USER (by default, root)\n"
+//usage:     "\nOptions:"
+//usage:     "\n	-,-l	Clear environment, run shell as login shell"
+//usage:     "\n	-p,-m	Do not set new $HOME, $SHELL, $USER, $LOGNAME"
+//usage:     "\n	-c CMD	Command to pass to 'sh -c'"
+//usage:     "\n	-s SH	Shell to use instead of user's default"
+
+#if ENABLE_FEATURE_SU_CHECKS_SHELLS
+/* Return 1 if SHELL is a restricted shell (one not returned by
+ * getusershell), else 0, meaning it is a standard shell.  */
+static int restricted_shell(const char *shell)
+{
+	char *line;
+	int result = 1;
+
+	/*setusershell(); - getusershell does it itself*/
+	while ((line = getusershell()) != NULL) {
+		if (/* *line != '#' && */ strcmp(line, shell) == 0) {
+			result = 0;
+			break;
+		}
+	}
+	if (ENABLE_FEATURE_CLEAN_UP)
+		endusershell();
+	return result;
+}
+#endif
+
 #define SU_OPT_mp (3)
-#define SU_OPT_l (4)
+#define SU_OPT_l  (4)
 
-int su_main(int argc, char **argv)
+int su_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int su_main(int argc UNUSED_PARAM, char **argv)
 {
 	unsigned flags;
-	char *opt_shell = 0;
-	char *opt_command = 0;
-	char *opt_username = "root";
+	char *opt_shell = NULL;
+	char *opt_command = NULL;
+	const char *opt_username = "root";
 	struct passwd *pw;
 	uid_t cur_uid = getuid();
 	const char *tty;
-	char *old_user;
+#if ENABLE_FEATURE_UTMP
+	char user_buf[64];
+#endif
+	const char *old_user;
 
-	flags = getopt32(argc, argv, "mplc:s:", &opt_command, &opt_shell);
-	argc -= optind;
+	flags = getopt32(argv, "mplc:s:", &opt_command, &opt_shell);
+	//argc -= optind;
 	argv += optind;
 
-	if (argc && LONE_DASH(argv[0])) {
+	if (argv[0] && LONE_DASH(argv[0])) {
 		flags |= SU_OPT_l;
-		argc--;
 		argv++;
 	}
 
 	/* get user if specified */
-	if (argc) {
+	if (argv[0]) {
 		opt_username = argv[0];
-//		argc--;
 		argv++;
 	}
 
 	if (ENABLE_FEATURE_SU_SYSLOG) {
-		/* The utmp entry (via getlogin) is probably the best way to identify
-		the user, especially if someone su's from a su-shell.
-		But getlogin can fail -- usually due to lack of utmp entry.
-		in this case resort to getpwuid.  */
-		old_user = xstrdup(USE_FEATURE_UTMP(getlogin() ? : ) (pw = getpwuid(cur_uid)) ? pw->pw_name : "");
-		tty = ttyname(2) ? : "none";
+		/* The utmp entry (via getlogin) is probably the best way to
+		 * identify the user, especially if someone su's from a su-shell.
+		 * But getlogin can fail -- usually due to lack of utmp entry.
+		 * in this case resort to getpwuid.  */
+#if ENABLE_FEATURE_UTMP
+		old_user = user_buf;
+		if (getlogin_r(user_buf, sizeof(user_buf)) != 0)
+#endif
+		{
+			pw = getpwuid(cur_uid);
+			old_user = pw ? xstrdup(pw->pw_name) : "";
+		}
+		tty = xmalloc_ttyname(2);
+		if (!tty) {
+			tty = "none";
+		}
 		openlog(applet_name, 0, LOG_AUTH);
 	}
 
-	pw = getpwnam(opt_username);
-	if (!pw)
-		bb_error_msg_and_die("unknown id: %s", opt_username);
+	pw = xgetpwnam(opt_username);
 
-	/* Make sure pw->pw_shell is non-NULL.  It may be NULL when NEW_USER
-	   is a username that is retrieved via NIS (YP), but that doesn't have
-	   a default shell listed.  */
-	if (!pw->pw_shell || !pw->pw_shell[0])
-		pw->pw_shell = (char *)DEFAULT_SHELL;
-
-	if ((cur_uid == 0) || correct_password(pw)) {
+	if (cur_uid == 0 || correct_password(pw)) {
 		if (ENABLE_FEATURE_SU_SYSLOG)
 			syslog(LOG_NOTICE, "%c %s %s:%s",
 				'+', tty, old_user, opt_username);
@@ -72,31 +107,37 @@ int su_main(int argc, char **argv)
 
 	if (ENABLE_FEATURE_CLEAN_UP && ENABLE_FEATURE_SU_SYSLOG) {
 		closelog();
-		free(old_user);
 	}
 
-	if (!opt_shell && (flags & SU_OPT_mp))
+	if (!opt_shell && (flags & SU_OPT_mp)) {
+		/* -s SHELL is not given, but "preserve env" opt is */
 		opt_shell = getenv("SHELL");
+	}
 
 #if ENABLE_FEATURE_SU_CHECKS_SHELLS
-	if (opt_shell && cur_uid && restricted_shell(pw->pw_shell)) {
+	if (opt_shell && cur_uid != 0 && pw->pw_shell && restricted_shell(pw->pw_shell)) {
 		/* The user being su'd to has a nonstandard shell, and so is
-		   probably a uucp account or has restricted access.  Don't
-		   compromise the account by allowing access with a standard
-		   shell.  */
+		 * probably a uucp account or has restricted access.  Don't
+		 * compromise the account by allowing access with a standard
+		 * shell.  */
 		bb_error_msg("using restricted shell");
-		opt_shell = 0;
+		opt_shell = NULL; /* ignore -s PROG */
 	}
+	/* else: user can run whatever he wants via "su -s PROG USER".
+	 * This is safe since PROG is run under user's uid/gid. */
 #endif
 	if (!opt_shell)
 		opt_shell = pw->pw_shell;
 
 	change_identity(pw);
-	setup_environment(opt_shell, flags & SU_OPT_l, !(flags & SU_OPT_mp), pw);
-	USE_SELINUX(set_current_security_context(NULL);)
+	setup_environment(opt_shell,
+			((flags & SU_OPT_l) / SU_OPT_l * SETUP_ENV_CLEARENV)
+			+ (!(flags & SU_OPT_mp) * SETUP_ENV_CHANGEENV),
+			pw);
+	IF_SELINUX(set_current_security_context(NULL);)
 
 	/* Never returns */
 	run_shell(opt_shell, flags & SU_OPT_l, opt_command, (const char**)argv);
 
-	return EXIT_FAILURE;
+	/* return EXIT_FAILURE; - not reached */
 }