usr.bin/chpass/chpass.c

   1 /*      $NetBSD: chpass.c,v 1.33 2008/07/21 14:19:21 lukem Exp $        */
   2
   3 /*-
   4  * Copyright (c) 1988, 1993, 1994
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #ifndef lint
  34 __COPYRIGHT("@(#) Copyright (c) 1988, 1993, 1994\
  35  The Regents of the University of California.  All rights reserved.");
  36 #endif /* not lint */
  37
  38 #ifndef lint
  39 #if 0
  40 static char sccsid[] = "@(#)chpass.c    8.4 (Berkeley) 4/2/94";
  41 #else
  42 __RCSID("$NetBSD: chpass.c,v 1.33 2008/07/21 14:19:21 lukem Exp $");
  43 #endif
  44 #endif /* not lint */
  45
  46 #include <sys/param.h>
  47 #include <sys/stat.h>
  48 #include <sys/time.h>
  49 #include <sys/resource.h>
  50
  51 #include <ctype.h>
  52 #include <err.h>
  53 #include <errno.h>
  54 #include <fcntl.h>
  55 #include <pwd.h>
  56 #include <stdio.h>
  57 #include <stdlib.h>
  58 #include <string.h>
  59 #include <unistd.h>
  60 #include <util.h>
  61 #include <libgen.h>
  62
  63 #include "chpass.h"
  64 #include "pathnames.h"
  65
  66 static char tempname[] = "/tmp/pw.XXXXXX";
  67 uid_t uid;
  68 int use_yp;
  69
  70 void    (*Pw_error)(const char *, int, int);
  71
  72 #ifdef  YP
  73 extern  int _yp_check(char **); /* buried deep inside libc */
  74 #endif
  75
  76 void    baduser(void);
  77 void    cleanup(void);
  78 void    usage(void);
  79
  80 int
  81 main(int argc, char **argv)
  82 {
  83         enum { NEWSH, LOADENTRY, EDITENTRY } op;
  84         struct passwd *pw, lpw, old_pw;
  85         int ch, dfd, pfd, tfd;
  86 #ifdef YP
  87         int yflag = 0;
  88 #endif
  89         char *arg, *username = NULL;
  90
  91 #ifdef __GNUC__
  92         pw = NULL;              /* XXX gcc -Wuninitialized */
  93         arg = NULL;
  94 #endif
  95 #ifdef  YP
  96         use_yp = _yp_check(NULL);
  97 #endif
  98
  99         op = EDITENTRY;
 100         while ((ch = getopt(argc, argv, "a:s:ly")) != -1)
 101                 switch (ch) {
 102                 case 'a':
 103                         op = LOADENTRY;
 104                         arg = optarg;
 105                         break;
 106                 case 's':
 107                         op = NEWSH;
 108                         arg = optarg;
 109                         break;
 110                 case 'l':
 111                         use_yp = 0;
 112                         break;
 113                 case 'y':
 114 #ifdef  YP
 115                         if (!use_yp)
 116                                 errx(1, "YP not in use.");
 117                         yflag = 1;
 118 #else
 119                         errx(1, "YP support not compiled in.");
 120 #endif
 121                         break;
 122                 default:
 123                         usage();
 124                 }
 125         argc -= optind;
 126         argv += optind;
 127
 128         uid = getuid();
 129         switch (argc) {
 130         case 0:
 131                 /* nothing */
 132                 break;
 133
 134         case 1:
 135                 username = argv[0];
 136                 break;
 137
 138         default:
 139                 usage();
 140         }
 141
 142 #ifdef YP
 143         /*
 144          * We need to determine if we _really_ want to use YP.
 145          * If we defaulted to YP (i.e. were not given the -y flag),
 146          * and the master is not running rpc.yppasswdd, we check
 147          * to see if the user exists in the local passwd database.
 148          * If so, we use it, otherwise we error out.
 149          */
 150         if (use_yp && yflag == 0) {
 151                 if (check_yppasswdd()) {
 152                         /*
 153                          * We weren't able to contact rpc.yppasswdd.
 154                          * Check to see if we're in the local
 155                          * password database.  If we are, use it.
 156                          */
 157                         if (username != NULL)
 158                                 pw = getpwnam(username);
 159                         else
 160                                 pw = getpwuid(uid);
 161                         if (pw != NULL)
 162                                 use_yp = 0;
 163                         else {
 164                                 warnx("master YP server not running yppasswd"
 165                                     " daemon.");
 166                                 errx(1, "Can't change password.");
 167                         }
 168                 }
 169         }
 170 #endif
 171
 172 #ifdef YP
 173         if (use_yp)
 174                 Pw_error = yppw_error;
 175         else
 176 #endif
 177                 Pw_error = pw_error;
 178
 179 #ifdef  YP
 180         if (op == LOADENTRY && use_yp)
 181                 errx(1, "cannot load entry using YP.\n"
 182                     "\tUse the -l flag to load local.");
 183 #endif
 184
 185         if (op == EDITENTRY || op == NEWSH) {
 186                 if (username != NULL) {
 187                         pw = getpwnam(username);
 188                         if (pw == NULL)
 189                                 errx(1, "unknown user: %s", username);
 190                         if (uid && uid != pw->pw_uid)
 191                                 baduser();
 192                 } else {
 193                         pw = getpwuid(uid);
 194                         if (pw == NULL)
 195                                 errx(1, "unknown user: uid %u", uid);
 196                 }
 197
 198                 /* Make a copy for later verification */
 199                 old_pw = *pw;
 200                 old_pw.pw_gecos = strdup(old_pw.pw_gecos);
 201                 if (!old_pw.pw_gecos) {
 202                         err(1, "strdup");
 203                         /*NOTREACHED*/
 204                 }
 205         }
 206
 207         if (op == NEWSH) {
 208                 /* protect p_shell -- it thinks NULL is /bin/sh */
 209                 if (!arg[0])
 210                         usage();
 211                 if (p_shell(arg, pw, NULL))
 212                         (*Pw_error)(NULL, 0, 1);
 213         }
 214
 215         if (op == LOADENTRY) {
 216                 if (uid)
 217                         baduser();
 218                 pw = &lpw;
 219                 if (!pw_scan(arg, pw, NULL))
 220                         exit(1);
 221         }
 222
 223         /* Edit the user passwd information if requested. */
 224         if (op == EDITENTRY) {
 225                 struct stat sb;
 226
 227                 dfd = mkstemp(tempname);
 228                 if (dfd < 0 || fcntl(dfd, F_SETFD, 1) < 0)
 229                         (*Pw_error)(tempname, 1, 1);
 230                 if (atexit(cleanup)) {
 231                         cleanup();
 232                         errx(1, "couldn't register cleanup");
 233                 }
 234                 if (stat(dirname(tempname), &sb) == -1)
 235                         err(1, "couldn't stat `%s'", dirname(tempname));
 236                 if (!(sb.st_mode & S_ISTXT))
 237                         errx(1, "temporary directory `%s' is not sticky",
 238                             dirname(tempname));
 239
 240                 display(tempname, dfd, pw);
 241                 edit(tempname, pw);
 242         }
 243
 244 #ifdef  YP
 245         if (use_yp) {
 246                 if (pw_yp(pw, uid))
 247                         yppw_error((char *)NULL, 0, 1);
 248                 else
 249                         exit(0);
 250                 /* Will not exit from this if. */
 251         }
 252 #endif  /* YP */
 253
 254
 255         /*
 256          * Get the passwd lock file and open the passwd file for
 257          * reading.
 258          */
 259         pw_init();
 260         tfd = pw_lock(0);
 261         if (tfd < 0) {
 262                 if (errno != EEXIST)
 263                         err(1, "%s", _PATH_MASTERPASSWD_LOCK);
 264                 warnx("The passwd file is busy, waiting...");
 265                 tfd = pw_lock(10);
 266                 if (tfd < 0) {
 267                         if (errno != EEXIST)
 268                                 err(1, "%s", _PATH_MASTERPASSWD_LOCK);
 269                         errx(1, "The passwd file is still busy, "
 270                              "try again later.");
 271                 }
 272         }
 273         if (fcntl(tfd, F_SETFD, 1) < 0)
 274                 pw_error(_PATH_MASTERPASSWD_LOCK, 1, 1);
 275
 276         pfd = open(_PATH_MASTERPASSWD, O_RDONLY, 0);
 277         if (pfd < 0 || fcntl(pfd, F_SETFD, 1) < 0)
 278                 pw_error(_PATH_MASTERPASSWD, 1, 1);
 279
 280         /* Copy the passwd file to the lock file, updating pw. */
 281         pw_copy(pfd, tfd, pw, (op == LOADENTRY) ? NULL : &old_pw);
 282
 283         close(pfd);
 284         close(tfd);
 285
 286         /* Now finish the passwd file update. */
 287         if (pw_mkdb(username, 0) < 0)
 288                 pw_error(NULL, 0, 1);
 289
 290         exit(0);
 291 }
 292
 293 void
 294 baduser(void)
 295 {
 296
 297         errx(1, "%s", strerror(EACCES));
 298 }
 299
 300 void
 301 usage(void)
 302 {
 303
 304         (void)fprintf(stderr,
 305             "usage: %s [-a list] [-s shell] [-l] [user]\n"
 306             "       %s [-a list] [-s shell] [-y] [user]\n",
 307             getprogname(), getprogname());
 308         exit(1);
 309 }
 310
 311 void
 312 cleanup(void)
 313 {
 314
 315         (void)unlink(tempname);
 316 }