busybox/loginutils/su.c

/* vi: set sw=4 ts=4: */
/*
 *  Mini su implementation for busybox
 *
 *  Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
 */

#include "libbb.h"
#include <syslog.h>

#define SU_OPT_mp (3)
#define SU_OPT_l (4)

int su_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int su_main(int argc UNUSED_PARAM, char **argv)
{
	unsigned flags;
	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;

	flags = getopt32(argv, "mplc:s:", &opt_command, &opt_shell);
	//argc -= optind;
	argv += optind;

	if (argv[0] && LONE_DASH(argv[0])) {
		flags |= SU_OPT_l;
		argv++;
	}

	/* get user if specified */
	if (argv[0]) {
		opt_username = argv[0];
		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.  */
		const char *user;
#if ENABLE_FEATURE_UTMP
		char user_buf[64];
		user = user_buf;
		if (getlogin_r(user_buf, sizeof(user_buf)) != 0)
#endif
		{
			pw = getpwuid(cur_uid);
			user = pw ? pw->pw_name : "";
		}
		old_user = xstrdup(user);
		tty = xmalloc_ttyname(2);
		if (!tty) {
			tty = "none";
		}
		openlog(applet_name, 0, LOG_AUTH);
	}

	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 (ENABLE_FEATURE_SU_SYSLOG)
			syslog(LOG_NOTICE, "%c %s %s:%s",
				'+', tty, old_user, opt_username);
	} else {
		if (ENABLE_FEATURE_SU_SYSLOG)
			syslog(LOG_NOTICE, "%c %s %s:%s",
				'-', tty, old_user, opt_username);
		bb_error_msg_and_die("incorrect password");
	}

	if (ENABLE_FEATURE_CLEAN_UP && ENABLE_FEATURE_SU_SYSLOG) {
		closelog();
		free(old_user);
	}

	if (!opt_shell && (flags & SU_OPT_mp))
		opt_shell = getenv("SHELL");

#if ENABLE_FEATURE_SU_CHECKS_SHELLS
	if (opt_shell && cur_uid && 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.  */
		bb_error_msg("using restricted shell");
		opt_shell = NULL;
	}
#endif
	if (!opt_shell)
		opt_shell = pw->pw_shell;

	change_identity(pw);
	/* setup_environment params: shell, clear_env, change_env, pw */
	setup_environment(opt_shell, flags & SU_OPT_l, !(flags & SU_OPT_mp), 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; - not reached */
}
1	/* vi: set sw=4 ts=4: */
2	/*
3	* Mini su implementation for busybox
4	*
5	* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
6	*/
7
8	#include "libbb.h"
9	#include <syslog.h>
10
11	#define SU_OPT_mp (3)
12	#define SU_OPT_l (4)
13
14	int su_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
15	int su_main(int argc UNUSED_PARAM, char **argv)
16	{
17	unsigned flags;
18	char *opt_shell = NULL;
19	char *opt_command = NULL;
20	const char *opt_username = "root";
21	struct passwd *pw;
22	uid_t cur_uid = getuid();
23	const char *tty;
24	char *old_user;
25
26	flags = getopt32(argv, "mplc:s:", &opt_command, &opt_shell);
27	//argc -= optind;
28	argv += optind;
29
30	if (argv[0] && LONE_DASH(argv[0])) {
31	flags \|= SU_OPT_l;
32	argv++;
33	}
34
35	/* get user if specified */
36	if (argv[0]) {
37	opt_username = argv[0];
38	argv++;
39	}
40
41	if (ENABLE_FEATURE_SU_SYSLOG) {
42	/* The utmp entry (via getlogin) is probably the best way to identify
43	* the user, especially if someone su's from a su-shell.
44	* But getlogin can fail -- usually due to lack of utmp entry.
45	* in this case resort to getpwuid. */
46	const char *user;
47	#if ENABLE_FEATURE_UTMP
48	char user_buf[64];
49	user = user_buf;
50	if (getlogin_r(user_buf, sizeof(user_buf)) != 0)
51	#endif
52	{
53	pw = getpwuid(cur_uid);
54	user = pw ? pw->pw_name : "";
55	}
56	old_user = xstrdup(user);
57	tty = xmalloc_ttyname(2);
58	if (!tty) {
59	tty = "none";
60	}
61	openlog(applet_name, 0, LOG_AUTH);
62	}
63
64	pw = xgetpwnam(opt_username);
65
66	/* Make sure pw->pw_shell is non-NULL. It may be NULL when NEW_USER
67	is a username that is retrieved via NIS (YP), but that doesn't have
68	a default shell listed. */
69	if (!pw->pw_shell \|\| !pw->pw_shell[0])
70	pw->pw_shell = (char *)DEFAULT_SHELL;
71
72	if ((cur_uid == 0) \|\| correct_password(pw)) {
73	if (ENABLE_FEATURE_SU_SYSLOG)
74	syslog(LOG_NOTICE, "%c %s %s:%s",
75	'+', tty, old_user, opt_username);
76	} else {
77	if (ENABLE_FEATURE_SU_SYSLOG)
78	syslog(LOG_NOTICE, "%c %s %s:%s",
79	'-', tty, old_user, opt_username);
80	bb_error_msg_and_die("incorrect password");
81	}
82
83	if (ENABLE_FEATURE_CLEAN_UP && ENABLE_FEATURE_SU_SYSLOG) {
84	closelog();
85	free(old_user);
86	}
87
88	if (!opt_shell && (flags & SU_OPT_mp))
89	opt_shell = getenv("SHELL");
90
91	#if ENABLE_FEATURE_SU_CHECKS_SHELLS
92	if (opt_shell && cur_uid && restricted_shell(pw->pw_shell)) {
93	/* The user being su'd to has a nonstandard shell, and so is
94	probably a uucp account or has restricted access. Don't
95	compromise the account by allowing access with a standard
96	shell. */
97	bb_error_msg("using restricted shell");
98	opt_shell = NULL;
99	}
100	#endif
101	if (!opt_shell)
102	opt_shell = pw->pw_shell;
103
104	change_identity(pw);
105	/* setup_environment params: shell, clear_env, change_env, pw */
106	setup_environment(opt_shell, flags & SU_OPT_l, !(flags & SU_OPT_mp), pw);
107	IF_SELINUX(set_current_security_context(NULL);)
108
109	/* Never returns */
110	run_shell(opt_shell, flags & SU_OPT_l, opt_command, (const char**)argv);
111
112	/* return EXIT_FAILURE; - not reached */
113	}