1 /* vi: set sw=4 ts=4: */
2 /*
3 * adduser - add users to /etc/passwd and /etc/shadow
4 *
5 * Copyright (C) 1999 by Lineo, inc. and John Beppu
6 * Copyright (C) 1999,2000,2001 by John Beppu <beppu@codepoet.org>
7 *
8 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
9 */
10 //config:config ADDUSER
11 //config: bool "adduser"
12 //config: default y
13 //config: help
14 //config: Utility for creating a new user account.
15 //config:
16 //config:config FEATURE_ADDUSER_LONG_OPTIONS
17 //config: bool "Enable long options"
18 //config: default y
19 //config: depends on ADDUSER && LONG_OPTS
20 //config: help
21 //config: Support long options for the adduser applet.
22 //config:
23 //config:config FEATURE_CHECK_NAMES
24 //config: bool "Enable sanity check on user/group names in adduser and addgroup"
25 //config: default n
26 //config: depends on ADDUSER || ADDGROUP
27 //config: help
28 //config: Enable sanity check on user and group names in adduser and addgroup.
29 //config: To avoid problems, the user or group name should consist only of
30 //config: letters, digits, underscores, periods, at signs and dashes,
31 //config: and not start with a dash (as defined by IEEE Std 1003.1-2001).
32 //config: For compatibility with Samba machine accounts "$" is also supported
33 //config: at the end of the user or group name.
34 //config:
35 //config:config LAST_ID
36 //config: int "Last valid uid or gid for adduser and addgroup"
37 //config: depends on ADDUSER || ADDGROUP
38 //config: default 60000
39 //config: help
40 //config: Last valid uid or gid for adduser and addgroup
41 //config:
42 //config:config FIRST_SYSTEM_ID
43 //config: int "First valid system uid or gid for adduser and addgroup"
44 //config: depends on ADDUSER || ADDGROUP
45 //config: range 0 LAST_ID
46 //config: default 100
47 //config: help
48 //config: First valid system uid or gid for adduser and addgroup
49 //config:
50 //config:config LAST_SYSTEM_ID
51 //config: int "Last valid system uid or gid for adduser and addgroup"
52 //config: depends on ADDUSER || ADDGROUP
53 //config: range FIRST_SYSTEM_ID LAST_ID
54 //config: default 999
55 //config: help
56 //config: Last valid system uid or gid for adduser and addgroup
57
58 //applet:IF_ADDUSER(APPLET(adduser, BB_DIR_USR_SBIN, BB_SUID_DROP))
59
60 //kbuild:lib-$(CONFIG_ADDUSER) += adduser.o
61
62 //usage:#define adduser_trivial_usage
63 //usage: "[OPTIONS] USER [GROUP]"
64 //usage:#define adduser_full_usage "\n\n"
65 //usage: "Create new user, or add USER to GROUP\n"
66 //usage: "\n -h DIR Home directory"
67 //usage: "\n -g GECOS GECOS field"
68 //usage: "\n -s SHELL Login shell"
69 //usage: "\n -G GRP Add user to existing group"
70 //usage: "\n -S Create a system user"
71 //usage: "\n -D Don't assign a password"
72 //usage: "\n -H Don't create home directory"
73 //usage: "\n -u UID User id"
74 //usage: "\n -k SKEL Skeleton directory (/etc/skel)"
75
76 #include "libbb.h"
77
78 #if CONFIG_LAST_SYSTEM_ID < CONFIG_FIRST_SYSTEM_ID
79 #error Bad LAST_SYSTEM_ID or FIRST_SYSTEM_ID in .config
80 #endif
81 #if CONFIG_LAST_ID < CONFIG_LAST_SYSTEM_ID
82 #error Bad LAST_ID or LAST_SYSTEM_ID in .config
83 #endif
84
85
86 /* #define OPT_HOME (1 << 0) */ /* unused */
87 /* #define OPT_GECOS (1 << 1) */ /* unused */
88 #define OPT_SHELL (1 << 2)
89 #define OPT_GID (1 << 3)
90 #define OPT_DONT_SET_PASS (1 << 4)
91 #define OPT_SYSTEM_ACCOUNT (1 << 5)
92 #define OPT_DONT_MAKE_HOME (1 << 6)
93 #define OPT_UID (1 << 7)
94 #define OPT_SKEL (1 << 8)
95
96 /* remix */
97 /* recoded such that the uid may be passed in *p */
passwd_study(struct passwd * p)98 static void passwd_study(struct passwd *p)
99 {
100 int max = CONFIG_LAST_ID;
101
102 if (getpwnam(p->pw_name)) {
103 bb_error_msg_and_die("%s '%s' in use", "user", p->pw_name);
104 /* this format string is reused in adduser and addgroup */
105 }
106
107 if (!(option_mask32 & OPT_UID)) {
108 if (option_mask32 & OPT_SYSTEM_ACCOUNT) {
109 p->pw_uid = CONFIG_FIRST_SYSTEM_ID;
110 max = CONFIG_LAST_SYSTEM_ID;
111 } else {
112 p->pw_uid = CONFIG_LAST_SYSTEM_ID + 1;
113 }
114 }
115 /* check for a free uid (and maybe gid) */
116 while (getpwuid(p->pw_uid) || (p->pw_gid == (gid_t)-1 && getgrgid(p->pw_uid))) {
117 if (option_mask32 & OPT_UID) {
118 /* -u N, cannot pick uid other than N: error */
119 bb_error_msg_and_die("%s '%s' in use", "uid", itoa(p->pw_uid));
120 /* this format string is reused in adduser and addgroup */
121 }
122 if (p->pw_uid == max) {
123 bb_error_msg_and_die("no %cids left", 'u');
124 /* this format string is reused in adduser and addgroup */
125 }
126 p->pw_uid++;
127 }
128
129 if (p->pw_gid == (gid_t)-1) {
130 p->pw_gid = p->pw_uid; /* new gid = uid */
131 if (getgrnam(p->pw_name)) {
132 bb_error_msg_and_die("%s '%s' in use", "group", p->pw_name);
133 /* this format string is reused in adduser and addgroup */
134 }
135 }
136 }
137
addgroup_wrapper(struct passwd * p,const char * group_name)138 static int addgroup_wrapper(struct passwd *p, const char *group_name)
139 {
140 char *argv[6];
141
142 argv[0] = (char*)"addgroup";
143 if (group_name) {
144 /* Add user to existing group */
145 argv[1] = (char*)"--";
146 argv[2] = p->pw_name;
147 argv[3] = (char*)group_name;
148 argv[4] = NULL;
149 } else {
150 /* Add user to his own group with the first free gid
151 * found in passwd_study.
152 */
153 #if ENABLE_FEATURE_ADDGROUP_LONG_OPTIONS || !ENABLE_ADDGROUP
154 /* We try to use --gid, not -g, because "standard" addgroup
155 * has no short option -g, it has only long --gid.
156 */
157 argv[1] = (char*)"--gid";
158 #else
159 /* Breaks if system in fact does NOT use busybox addgroup */
160 argv[1] = (char*)"-g";
161 #endif
162 argv[2] = utoa(p->pw_gid);
163 argv[3] = (char*)"--";
164 argv[4] = p->pw_name;
165 argv[5] = NULL;
166 }
167
168 return spawn_and_wait(argv);
169 }
170
171 static void passwd_wrapper(const char *login_name) NORETURN;
172
passwd_wrapper(const char * login_name)173 static void passwd_wrapper(const char *login_name)
174 {
175 BB_EXECLP("passwd", "passwd", "--", login_name, NULL);
176 bb_error_msg_and_die("can't execute passwd, you must set password manually");
177 }
178
179 #if ENABLE_FEATURE_ADDUSER_LONG_OPTIONS
180 static const char adduser_longopts[] ALIGN1 =
181 "home\0" Required_argument "h"
182 "gecos\0" Required_argument "g"
183 "shell\0" Required_argument "s"
184 "ingroup\0" Required_argument "G"
185 "disabled-password\0" No_argument "D"
186 "empty-password\0" No_argument "D"
187 "system\0" No_argument "S"
188 "no-create-home\0" No_argument "H"
189 "uid\0" Required_argument "u"
190 "skel\0" Required_argument "k"
191 ;
192 #endif
193
194 /*
195 * adduser will take a login_name as its first parameter.
196 * home, shell, gecos:
197 * can be customized via command-line parameters.
198 */
199 int adduser_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
adduser_main(int argc UNUSED_PARAM,char ** argv)200 int adduser_main(int argc UNUSED_PARAM, char **argv)
201 {
202 struct passwd pw;
203 const char *usegroup = NULL;
204 char *p;
205 unsigned opts;
206 char *uid;
207 const char *skel = "/etc/skel";
208
209 #if ENABLE_FEATURE_ADDUSER_LONG_OPTIONS
210 applet_long_options = adduser_longopts;
211 #endif
212
213 /* got root? */
214 if (geteuid()) {
215 bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
216 }
217
218 pw.pw_gecos = (char *)"Linux User,,,";
219 /* We assume that newly created users "inherit" root's shell setting */
220 pw.pw_shell = (char *)get_shell_name();
221 pw.pw_dir = NULL;
222
223 /* at least one and at most two non-option args */
224 /* disable interactive passwd for system accounts */
225 opt_complementary = "-1:?2:SD";
226 opts = getopt32(argv, "h:g:s:G:DSHu:k:", &pw.pw_dir, &pw.pw_gecos, &pw.pw_shell, &usegroup, &uid, &skel);
227 if (opts & OPT_UID)
228 pw.pw_uid = xatou_range(uid, 0, CONFIG_LAST_ID);
229
230 argv += optind;
231 pw.pw_name = argv[0];
232
233 if (!opts && argv[1]) {
234 /* if called with two non-option arguments, adduser
235 * will add an existing user to an existing group.
236 */
237 return addgroup_wrapper(&pw, argv[1]);
238 }
239
240 /* fill in the passwd struct */
241 die_if_bad_username(pw.pw_name);
242 if (!pw.pw_dir) {
243 /* create string for $HOME if not specified already */
244 pw.pw_dir = xasprintf("/home/%s", argv[0]);
245 }
246 pw.pw_passwd = (char *)"x";
247 if (opts & OPT_SYSTEM_ACCOUNT) {
248 if (!usegroup) {
249 usegroup = "nogroup";
250 }
251 if (!(opts & OPT_SHELL)) {
252 pw.pw_shell = (char *) "/bin/false";
253 }
254 }
255 pw.pw_gid = usegroup ? xgroup2gid(usegroup) : -1; /* exits on failure */
256
257 /* make sure everything is kosher and setup uid && maybe gid */
258 passwd_study(&pw);
259
260 p = xasprintf("x:%u:%u:%s:%s:%s",
261 (unsigned) pw.pw_uid, (unsigned) pw.pw_gid,
262 pw.pw_gecos, pw.pw_dir, pw.pw_shell);
263 if (update_passwd(bb_path_passwd_file, pw.pw_name, p, NULL) < 0) {
264 return EXIT_FAILURE;
265 }
266 if (ENABLE_FEATURE_CLEAN_UP)
267 free(p);
268 #if ENABLE_FEATURE_SHADOWPASSWDS
269 /* /etc/shadow fields:
270 * 1. username
271 * 2. encrypted password
272 * 3. last password change (unix date (unix time/24*60*60))
273 * 4. minimum days required between password changes
274 * 5. maximum days password is valid
275 * 6. days before password is to expire that user is warned
276 * 7. days after password expires that account is disabled
277 * 8. unix date when login expires (i.e. when it may no longer be used)
278 */
279 /* fields: 2 3 4 5 6 78 */
280 p = xasprintf("!:%u:0:99999:7:::", (unsigned)(time(NULL)) / (24*60*60));
281 /* ignore errors: if file is missing we suppose admin doesn't want it */
282 update_passwd(bb_path_shadow_file, pw.pw_name, p, NULL);
283 if (ENABLE_FEATURE_CLEAN_UP)
284 free(p);
285 #endif
286
287 /* add to group */
288 addgroup_wrapper(&pw, usegroup);
289
290 /* clear the umask for this process so it doesn't
291 * screw up the permissions on the mkdir and chown. */
292 umask(0);
293 if (!(opts & OPT_DONT_MAKE_HOME)) {
294 /* set the owner and group so it is owned by the new user,
295 * then fix up the permissions to 2755. Can't do it before
296 * since chown will clear the setgid bit */
297 int mkdir_err = mkdir(pw.pw_dir, 0755);
298 if (mkdir_err == 0) {
299 /* New home. Copy /etc/skel to it */
300 const char *args[] = {
301 "chown",
302 "-R",
303 xasprintf("%u:%u", (int)pw.pw_uid, (int)pw.pw_gid),
304 pw.pw_dir,
305 NULL
306 };
307 /* Be silent on any errors (like: no /etc/skel) */
308 if (!(opts & OPT_SKEL))
309 logmode = LOGMODE_NONE;
310 copy_file(skel, pw.pw_dir, FILEUTILS_RECUR);
311 logmode = LOGMODE_STDIO;
312 chown_main(4, (char**)args);
313 }
314 if ((mkdir_err != 0 && errno != EEXIST)
315 || chown(pw.pw_dir, pw.pw_uid, pw.pw_gid) != 0
316 || chmod(pw.pw_dir, 02755) != 0 /* set setgid bit on homedir */
317 ) {
318 bb_simple_perror_msg(pw.pw_dir);
319 }
320 }
321
322 if (!(opts & OPT_DONT_SET_PASS)) {
323 /* interactively set passwd */
324 passwd_wrapper(pw.pw_name);
325 }
326
327 return EXIT_SUCCESS;
328 }
329