Contents of /trunk/mkinitrd-magellan/busybox/loginutils/su.c
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Wed Aug 18 21:56:57 2010 UTC (14 years, 1 month ago) by niro
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Wed Aug 18 21:56:57 2010 UTC (14 years, 1 month ago) by niro
File MIME type: text/plain
File size: 3601 byte(s)
-updated to busybox-1.17.1
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 | #if ENABLE_FEATURE_SU_CHECKS_SHELLS |
12 | /* Return 1 if SHELL is a restricted shell (one not returned by |
13 | * getusershell), else 0, meaning it is a standard shell. */ |
14 | static int restricted_shell(const char *shell) |
15 | { |
16 | char *line; |
17 | int result = 1; |
18 | |
19 | /*setusershell(); - getusershell does it itself*/ |
20 | while ((line = getusershell()) != NULL) { |
21 | if (/* *line != '#' && */ strcmp(line, shell) == 0) { |
22 | result = 0; |
23 | break; |
24 | } |
25 | } |
26 | if (ENABLE_FEATURE_CLEAN_UP) |
27 | endusershell(); |
28 | return result; |
29 | } |
30 | #endif |
31 | |
32 | #define SU_OPT_mp (3) |
33 | #define SU_OPT_l (4) |
34 | |
35 | int su_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
36 | int su_main(int argc UNUSED_PARAM, char **argv) |
37 | { |
38 | unsigned flags; |
39 | char *opt_shell = NULL; |
40 | char *opt_command = NULL; |
41 | const char *opt_username = "root"; |
42 | struct passwd *pw; |
43 | uid_t cur_uid = getuid(); |
44 | const char *tty; |
45 | char user_buf[64]; |
46 | const char *old_user; |
47 | |
48 | flags = getopt32(argv, "mplc:s:", &opt_command, &opt_shell); |
49 | //argc -= optind; |
50 | argv += optind; |
51 | |
52 | if (argv[0] && LONE_DASH(argv[0])) { |
53 | flags |= SU_OPT_l; |
54 | argv++; |
55 | } |
56 | |
57 | /* get user if specified */ |
58 | if (argv[0]) { |
59 | opt_username = argv[0]; |
60 | argv++; |
61 | } |
62 | |
63 | if (ENABLE_FEATURE_SU_SYSLOG) { |
64 | /* The utmp entry (via getlogin) is probably the best way to |
65 | * identify the user, especially if someone su's from a su-shell. |
66 | * But getlogin can fail -- usually due to lack of utmp entry. |
67 | * in this case resort to getpwuid. */ |
68 | #if ENABLE_FEATURE_UTMP |
69 | old_user = user_buf; |
70 | if (getlogin_r(user_buf, sizeof(user_buf)) != 0) |
71 | #endif |
72 | { |
73 | pw = getpwuid(cur_uid); |
74 | old_user = pw ? xstrdup(pw->pw_name) : ""; |
75 | } |
76 | tty = xmalloc_ttyname(2); |
77 | if (!tty) { |
78 | tty = "none"; |
79 | } |
80 | openlog(applet_name, 0, LOG_AUTH); |
81 | } |
82 | |
83 | pw = xgetpwnam(opt_username); |
84 | |
85 | if (cur_uid == 0 || correct_password(pw)) { |
86 | if (ENABLE_FEATURE_SU_SYSLOG) |
87 | syslog(LOG_NOTICE, "%c %s %s:%s", |
88 | '+', tty, old_user, opt_username); |
89 | } else { |
90 | if (ENABLE_FEATURE_SU_SYSLOG) |
91 | syslog(LOG_NOTICE, "%c %s %s:%s", |
92 | '-', tty, old_user, opt_username); |
93 | bb_error_msg_and_die("incorrect password"); |
94 | } |
95 | |
96 | if (ENABLE_FEATURE_CLEAN_UP && ENABLE_FEATURE_SU_SYSLOG) { |
97 | closelog(); |
98 | } |
99 | |
100 | if (!opt_shell && (flags & SU_OPT_mp)) { |
101 | /* -s SHELL is not given, but "preserve env" opt is */ |
102 | opt_shell = getenv("SHELL"); |
103 | } |
104 | |
105 | /* Make sure pw->pw_shell is non-NULL. It may be NULL when NEW_USER |
106 | * is a username that is retrieved via NIS (YP), that doesn't have |
107 | * a default shell listed. */ |
108 | if (!pw->pw_shell || !pw->pw_shell[0]) |
109 | pw->pw_shell = (char *)DEFAULT_SHELL; |
110 | |
111 | #if ENABLE_FEATURE_SU_CHECKS_SHELLS |
112 | if (opt_shell && cur_uid != 0 && restricted_shell(pw->pw_shell)) { |
113 | /* The user being su'd to has a nonstandard shell, and so is |
114 | * probably a uucp account or has restricted access. Don't |
115 | * compromise the account by allowing access with a standard |
116 | * shell. */ |
117 | bb_error_msg("using restricted shell"); |
118 | opt_shell = NULL; |
119 | } |
120 | /* else: user can run whatever he wants via "su -s PROG USER". |
121 | * This is safe since PROG is run under user's uid/gid. */ |
122 | #endif |
123 | if (!opt_shell) |
124 | opt_shell = pw->pw_shell; |
125 | |
126 | change_identity(pw); |
127 | setup_environment(opt_shell, |
128 | ((flags & SU_OPT_l) / SU_OPT_l * SETUP_ENV_CLEARENV) |
129 | + (!(flags & SU_OPT_mp) * SETUP_ENV_CHANGEENV), |
130 | pw); |
131 | IF_SELINUX(set_current_security_context(NULL);) |
132 | |
133 | /* Never returns */ |
134 | run_shell(opt_shell, flags & SU_OPT_l, opt_command, (const char**)argv); |
135 | |
136 | /* return EXIT_FAILURE; - not reached */ |
137 | } |