Contents of /tags/mkinitrd-6_1_11/busybox/loginutils/su.c
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Wed Oct 28 13:31:19 2009 UTC (14 years, 11 months ago) by niro
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File size: 2845 byte(s)
Wed Oct 28 13:31:19 2009 UTC (14 years, 11 months ago) by niro
File MIME type: text/plain
File size: 2845 byte(s)
tagged 'mkinitrd-6_1_11'
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 | 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 | opt_shell = NULL; |
88 | } |
89 | #endif |
90 | if (!opt_shell) |
91 | opt_shell = pw->pw_shell; |
92 | |
93 | change_identity(pw); |
94 | /* setup_environment params: shell, clear_env, change_env, pw */ |
95 | 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 | /* return EXIT_FAILURE; - not reached */ |
102 | } |