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.  */
		old_user = xstrdup(USE_FEATURE_UTMP(getlogin() ? : ) (pw = getpwuid(cur_uid)) ? pw->pw_name : "");
		tty = ttyname(2) ? : "none";
		openlog(applet_name, 0, LOG_AUTH);
	}

	pw = getpwnam(opt_username);
	if (!pw)
		bb_error_msg_and_die("unknown id: %s", 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);
	USE_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	niro	532	/* 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	niro	816	#include "libbb.h"
9	niro	532	#include <syslog.h>
10
11			#define SU_OPT_mp (3)
12			#define SU_OPT_l (4)
13
14	niro	816	int su_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
15			int su_main(int argc UNUSED_PARAM, char **argv)
16	niro	532	{
17			unsigned flags;
18	niro	816	char *opt_shell = NULL;
19			char *opt_command = NULL;
20			const char *opt_username = "root";
21	niro	532	struct passwd *pw;
22			uid_t cur_uid = getuid();
23			const char *tty;
24			char *old_user;
25
26	niro	816	flags = getopt32(argv, "mplc:s:", &opt_command, &opt_shell);
27			//argc -= optind;
28	niro	532	argv += optind;
29
30	niro	816	if (argv[0] && LONE_DASH(argv[0])) {
31	niro	532	flags \|= SU_OPT_l;
32			argv++;
33			}
34
35			/* get user if specified */
36	niro	816	if (argv[0]) {
37	niro	532	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			old_user = xstrdup(USE_FEATURE_UTMP(getlogin() ? : ) (pw = getpwuid(cur_uid)) ? pw->pw_name : "");
47			tty = ttyname(2) ? : "none";
48			openlog(applet_name, 0, LOG_AUTH);
49			}
50
51			pw = getpwnam(opt_username);
52			if (!pw)
53			bb_error_msg_and_die("unknown id: %s", opt_username);
54
55			/* Make sure pw->pw_shell is non-NULL. It may be NULL when NEW_USER
56			is a username that is retrieved via NIS (YP), but that doesn't have
57			a default shell listed. */
58			if (!pw->pw_shell \|\| !pw->pw_shell[0])
59			pw->pw_shell = (char *)DEFAULT_SHELL;
60
61			if ((cur_uid == 0) \|\| correct_password(pw)) {
62			if (ENABLE_FEATURE_SU_SYSLOG)
63			syslog(LOG_NOTICE, "%c %s %s:%s",
64			'+', tty, old_user, opt_username);
65			} else {
66			if (ENABLE_FEATURE_SU_SYSLOG)
67			syslog(LOG_NOTICE, "%c %s %s:%s",
68			'-', tty, old_user, opt_username);
69			bb_error_msg_and_die("incorrect password");
70			}
71
72			if (ENABLE_FEATURE_CLEAN_UP && ENABLE_FEATURE_SU_SYSLOG) {
73			closelog();
74			free(old_user);
75			}
76
77			if (!opt_shell && (flags & SU_OPT_mp))
78			opt_shell = getenv("SHELL");
79
80			#if ENABLE_FEATURE_SU_CHECKS_SHELLS
81			if (opt_shell && cur_uid && restricted_shell(pw->pw_shell)) {
82			/* The user being su'd to has a nonstandard shell, and so is
83			probably a uucp account or has restricted access. Don't
84			compromise the account by allowing access with a standard
85			shell. */
86			bb_error_msg("using restricted shell");
87	niro	816	opt_shell = NULL;
88	niro	532	}
89			#endif
90			if (!opt_shell)
91			opt_shell = pw->pw_shell;
92
93			change_identity(pw);
94	niro	816	/* setup_environment params: shell, clear_env, change_env, pw */
95	niro	532	setup_environment(opt_shell, flags & SU_OPT_l, !(flags & SU_OPT_mp), pw);
96			USE_SELINUX(set_current_security_context(NULL);)
97
98			/* Never returns */
99			run_shell(opt_shell, flags & SU_OPT_l, opt_command, (const char**)argv);
100
101	niro	816	/* return EXIT_FAILURE; - not reached */
102	niro	532	}