loginutils/adduser.c

   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 (15 kb)"
  12 //config:       default y
  13 //config:       select LONG_OPTS
  14 //config:       help
  15 //config:       Utility for creating a new user account.
  16 //config:
  17 //config:config FEATURE_CHECK_NAMES
  18 //config:       bool "Enable sanity check on user/group names in adduser and addgroup"
  19 //config:       default n
  20 //config:       depends on ADDUSER || ADDGROUP
  21 //config:       help
  22 //config:       Enable sanity check on user and group names in adduser and addgroup.
  23 //config:       To avoid problems, the user or group name should consist only of
  24 //config:       letters, digits, underscores, periods, at signs and dashes,
  25 //config:       and not start with a dash (as defined by IEEE Std 1003.1-2001).
  26 //config:       For compatibility with Samba machine accounts "$" is also supported
  27 //config:       at the end of the user or group name.
  28 //config:
  29 //config:config LAST_ID
  30 //config:       int "Last valid uid or gid for adduser and addgroup"
  31 //config:       depends on ADDUSER || ADDGROUP
  32 //config:       default 60000
  33 //config:       help
  34 //config:       Last valid uid or gid for adduser and addgroup
  35 //config:
  36 //config:config FIRST_SYSTEM_ID
  37 //config:       int "First valid system uid or gid for adduser and addgroup"
  38 //config:       depends on ADDUSER || ADDGROUP
  39 //config:       range 0 LAST_ID
  40 //config:       default 100
  41 //config:       help
  42 //config:       First valid system uid or gid for adduser and addgroup
  43 //config:
  44 //config:config LAST_SYSTEM_ID
  45 //config:       int "Last valid system uid or gid for adduser and addgroup"
  46 //config:       depends on ADDUSER || ADDGROUP
  47 //config:       range FIRST_SYSTEM_ID LAST_ID
  48 //config:       default 999
  49 //config:       help
  50 //config:       Last valid system uid or gid for adduser and addgroup
  51
  52 //applet:IF_ADDUSER(APPLET_NOEXEC(adduser, adduser, BB_DIR_USR_SBIN, BB_SUID_DROP, adduser))
  53
  54 //kbuild:lib-$(CONFIG_ADDUSER) += adduser.o
  55
  56 //usage:#define adduser_trivial_usage
  57 //usage:       "[OPTIONS] USER [GROUP]"
  58 //usage:#define adduser_full_usage "\n\n"
  59 //usage:       "Create new user, or add USER to GROUP\n"
  60 //usage:     "\n        -h DIR          Home directory"
  61 //usage:     "\n        -g GECOS        GECOS field"
  62 //usage:     "\n        -s SHELL        Login shell"
  63 //usage:     "\n        -G GRP          Group"
  64 //usage:     "\n        -S              Create a system user"
  65 //usage:     "\n        -D              Don't assign a password"
  66 //usage:     "\n        -H              Don't create home directory"
  67 //usage:     "\n        -u UID          User id"
  68 //usage:     "\n        -k SKEL         Skeleton directory (/etc/skel)"
  69
  70 #include "libbb.h"
  71
  72 #if CONFIG_LAST_SYSTEM_ID < CONFIG_FIRST_SYSTEM_ID
  73 #error Bad LAST_SYSTEM_ID or FIRST_SYSTEM_ID in .config
  74 #endif
  75 #if CONFIG_LAST_ID < CONFIG_LAST_SYSTEM_ID
  76 #error Bad LAST_ID or LAST_SYSTEM_ID in .config
  77 #endif
  78
  79
  80 /* #define OPT_HOME           (1 << 0) */ /* unused */
  81 /* #define OPT_GECOS          (1 << 1) */ /* unused */
  82 #define OPT_SHELL          (1 << 2)
  83 #define OPT_GID            (1 << 3)
  84 #define OPT_DONT_SET_PASS  (1 << 4)
  85 #define OPT_SYSTEM_ACCOUNT (1 << 5)
  86 #define OPT_DONT_MAKE_HOME (1 << 6)
  87 #define OPT_UID            (1 << 7)
  88 #define OPT_SKEL           (1 << 8)
  89
  90 /* remix */
  91 /* recoded such that the uid may be passed in *p */
  92 static void passwd_study(struct passwd *p)
  93 {
  94         int max = CONFIG_LAST_ID;
  95
  96         if (getpwnam(p->pw_name)) {
  97                 bb_error_msg_and_die("%s '%s' in use", "user", p->pw_name);
  98                 /* this format string is reused in adduser and addgroup */
  99         }
 100
 101         if (!(option_mask32 & OPT_UID)) {
 102                 if (option_mask32 & OPT_SYSTEM_ACCOUNT) {
 103                         p->pw_uid = CONFIG_FIRST_SYSTEM_ID;
 104                         max = CONFIG_LAST_SYSTEM_ID;
 105                 } else {
 106                         p->pw_uid = CONFIG_LAST_SYSTEM_ID + 1;
 107                 }
 108         }
 109         /* check for a free uid (and maybe gid) */
 110         while (getpwuid(p->pw_uid) || (p->pw_gid == (gid_t)-1 && getgrgid(p->pw_uid))) {
 111                 if (option_mask32 & OPT_UID) {
 112                         /* -u N, cannot pick uid other than N: error */
 113                         bb_error_msg_and_die("%s '%s' in use", "uid", itoa(p->pw_uid));
 114                         /* this format string is reused in adduser and addgroup */
 115                 }
 116                 if (p->pw_uid == max) {
 117                         bb_error_msg_and_die("no %cids left", 'u');
 118                         /* this format string is reused in adduser and addgroup */
 119                 }
 120                 p->pw_uid++;
 121         }
 122
 123         if (p->pw_gid == (gid_t)-1) {
 124                 p->pw_gid = p->pw_uid; /* new gid = uid */
 125                 if (getgrnam(p->pw_name)) {
 126                         bb_error_msg_and_die("%s '%s' in use", "group", p->pw_name);
 127                         /* this format string is reused in adduser and addgroup */
 128                 }
 129         }
 130 }
 131
 132 static int addgroup_wrapper(struct passwd *p, const char *group_name)
 133 {
 134         char *argv[6];
 135
 136         argv[0] = (char*)"addgroup";
 137         if (group_name) {
 138                 /* Add user to existing group */
 139                 argv[1] = (char*)"--";
 140                 argv[2] = p->pw_name;
 141                 argv[3] = (char*)group_name;
 142                 argv[4] = NULL;
 143         } else {
 144                 /* Add user to his own group with the first free gid
 145                  * found in passwd_study.
 146                  */
 147                 argv[1] = (char*)"--gid";
 148                 argv[2] = utoa(p->pw_gid);
 149                 argv[3] = (char*)"--";
 150                 argv[4] = p->pw_name;
 151                 argv[5] = NULL;
 152         }
 153
 154         return spawn_and_wait(argv);
 155 }
 156
 157 static void passwd_wrapper(const char *login_name) NORETURN;
 158
 159 static void passwd_wrapper(const char *login_name)
 160 {
 161         BB_EXECLP("passwd", "passwd", "--", login_name, NULL);
 162         bb_simple_error_msg_and_die("can't execute passwd, you must set password manually");
 163 }
 164
 165 //FIXME: upstream adduser has no short options! NOT COMPATIBLE!
 166 static const char adduser_longopts[] ALIGN1 =
 167                 "home\0"                Required_argument "h"
 168                 "gecos\0"               Required_argument "g"
 169                 "shell\0"               Required_argument "s"
 170                 "ingroup\0"             Required_argument "G"
 171                 "disabled-password\0"   No_argument       "D"
 172                 "empty-password\0"      No_argument       "D"
 173                 "system\0"              No_argument       "S"
 174                 "no-create-home\0"      No_argument       "H"
 175                 "uid\0"                 Required_argument "u"
 176                 "skel\0"                Required_argument "k"
 177                 ;
 178
 179 /*
 180  * adduser will take a login_name as its first parameter.
 181  * home, shell, gecos:
 182  * can be customized via command-line parameters.
 183  */
 184 int adduser_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 185 int adduser_main(int argc UNUSED_PARAM, char **argv)
 186 {
 187         struct passwd pw;
 188         const char *usegroup = NULL;
 189         char *p;
 190         unsigned opts;
 191         char *uid;
 192         const char *skel = "/etc/skel";
 193
 194         /* got root? */
 195         if (geteuid()) {
 196                 bb_simple_error_msg_and_die(bb_msg_perm_denied_are_you_root);
 197         }
 198
 199         pw.pw_gecos = (char *)"Linux User,,,";
 200         /* We assume that newly created users "inherit" root's shell setting */
 201         pw.pw_shell = xstrdup(get_shell_name()); /* might come from getpwnam(), need to make a copy */
 202         pw.pw_dir = NULL;
 203
 204         opts = getopt32long(argv, "^"
 205                         "h:g:s:G:DSHu:k:"
 206                         /* at least one and at most two non-option args */
 207                         /* disable interactive passwd for system accounts */
 208                         "\0" "-1:?2:SD",
 209                         adduser_longopts,
 210                         &pw.pw_dir, &pw.pw_gecos, &pw.pw_shell,
 211                         &usegroup, &uid, &skel
 212         );
 213         if (opts & OPT_UID)
 214                 pw.pw_uid = xatou_range(uid, 0, CONFIG_LAST_ID);
 215
 216         argv += optind;
 217         pw.pw_name = argv[0];
 218
 219         if (!opts && argv[1]) {
 220                 /* if called with two non-option arguments, adduser
 221                  * will add an existing user to an existing group.
 222                  */
 223                 return addgroup_wrapper(&pw, argv[1]);
 224         }
 225
 226         /* fill in the passwd struct */
 227         die_if_bad_username(pw.pw_name);
 228         if (!pw.pw_dir) {
 229                 /* create string for $HOME if not specified already */
 230                 pw.pw_dir = xasprintf("/home/%s", argv[0]);
 231         }
 232         pw.pw_passwd = (char *)"x";
 233         if (opts & OPT_SYSTEM_ACCOUNT) {
 234                 if (!usegroup) {
 235                         usegroup = "nogroup";
 236                 }
 237                 if (!(opts & OPT_SHELL)) {
 238                         pw.pw_shell = (char *) "/bin/false";
 239                 }
 240         }
 241         pw.pw_gid = usegroup ? xgroup2gid(usegroup) : -1; /* exits on failure */
 242
 243         /* make sure everything is kosher and setup uid && maybe gid */
 244         passwd_study(&pw);
 245
 246         p = xasprintf("x:%u:%u:%s:%s:%s",
 247                         (unsigned) pw.pw_uid, (unsigned) pw.pw_gid,
 248                         pw.pw_gecos, pw.pw_dir, pw.pw_shell);
 249         if (update_passwd(bb_path_passwd_file, pw.pw_name, p, NULL) < 0) {
 250                 return EXIT_FAILURE;
 251         }
 252         if (ENABLE_FEATURE_CLEAN_UP)
 253                 free(p);
 254 #if ENABLE_FEATURE_SHADOWPASSWDS
 255         /* /etc/shadow fields:
 256          * 1. username
 257          * 2. encrypted password
 258          * 3. last password change (unix date (unix time/24*60*60))
 259          * 4. minimum days required between password changes
 260          * 5. maximum days password is valid
 261          * 6. days before password is to expire that user is warned
 262          * 7. days after password expires that account is disabled
 263          * 8. unix date when login expires (i.e. when it may no longer be used)
 264          */
 265         /* fields:     2 3  4 5     6 78 */
 266         p = xasprintf("!:%u:0:99999:7:::", (unsigned)(time(NULL)) / (24*60*60));
 267         /* ignore errors: if file is missing we suppose admin doesn't want it */
 268         update_passwd(bb_path_shadow_file, pw.pw_name, p, NULL);
 269         if (ENABLE_FEATURE_CLEAN_UP)
 270                 free(p);
 271 #endif
 272
 273         /* add to group */
 274         addgroup_wrapper(&pw, usegroup);
 275
 276         /* clear the umask for this process so it doesn't
 277          * screw up the permissions on the mkdir and chown. */
 278         umask(0);
 279         if (!(opts & OPT_DONT_MAKE_HOME)) {
 280                 /* set the owner and group so it is owned by the new user,
 281                  * then fix up the permissions to 2755. Can't do it before
 282                  * since chown will clear the setgid bit */
 283                 int mkdir_err = mkdir(pw.pw_dir, 0755);
 284                 if (mkdir_err == 0) {
 285                         /* New home. Copy /etc/skel to it */
 286                         const char *args[] = {
 287                                 "chown",
 288                                 "-R",
 289                                 xasprintf("%u:%u", (int)pw.pw_uid, (int)pw.pw_gid),
 290                                 pw.pw_dir,
 291                                 NULL
 292                         };
 293                         /* Be silent on any errors (like: no /etc/skel) */
 294                         if (!(opts & OPT_SKEL))
 295                                 logmode = LOGMODE_NONE;
 296                         copy_file(skel, pw.pw_dir, FILEUTILS_RECUR);
 297                         logmode = LOGMODE_STDIO;
 298                         chown_main(4, (char**)args);
 299                 }
 300                 if ((mkdir_err != 0 && errno != EEXIST)
 301                  || chown(pw.pw_dir, pw.pw_uid, pw.pw_gid) != 0
 302                  || chmod(pw.pw_dir, 02755) != 0 /* set setgid bit on homedir */
 303                 ) {
 304                         bb_simple_perror_msg(pw.pw_dir);
 305                 }
 306         }
 307
 308         if (!(opts & OPT_DONT_SET_PASS)) {
 309                 /* interactively set passwd */
 310                 passwd_wrapper(pw.pw_name);
 311         }
 312
 313         return EXIT_SUCCESS;
 314 }