lib/libutil/passwd.c

   1 /*      $NetBSD: passwd.c,v 1.50 2010/08/18 08:32:02 christos Exp $     */
   2
   3 /*
   4  * Copyright (c) 1987, 1993, 1994, 1995
   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 #if defined(LIBC_SCCS) && !defined(lint)
  34 __RCSID("$NetBSD: passwd.c,v 1.50 2010/08/18 08:32:02 christos Exp $");
  35 #endif /* LIBC_SCCS and not lint */
  36
  37 #include <sys/types.h>
  38 #include <sys/param.h>
  39 #include <sys/stat.h>
  40 #include <sys/time.h>
  41 #include <sys/resource.h>
  42 #include <sys/wait.h>
  43
  44 #include <assert.h>
  45 #include <ctype.h>
  46 #include <err.h>
  47 #include <errno.h>
  48 #include <fcntl.h>
  49 #include <limits.h>
  50 #include <paths.h>
  51 #include <pwd.h>
  52 #include <grp.h>
  53 #include <signal.h>
  54 #include <stdio.h>
  55 #include <stdlib.h>
  56 #include <string.h>
  57 #include <unistd.h>
  58 #include <util.h>
  59
  60 static const char      *pw_filename(const char *filename);
  61 static void             pw_cont(int sig);
  62 static const char *     pw_equal(char *buf, struct passwd *old_pw);
  63 static const char      *pw_default(const char *option);
  64 static int              read_line(FILE *fp, char *line, int max);
  65 static void             trim_whitespace(char *line);
  66
  67 static  char    pw_prefix[MAXPATHLEN];
  68
  69 const char *
  70 pw_getprefix(void)
  71 {
  72
  73         return(pw_prefix);
  74 }
  75
  76 int
  77 pw_setprefix(const char *new_prefix)
  78 {
  79         size_t length;
  80
  81         _DIAGASSERT(new_prefix != NULL);
  82
  83         length = strlen(new_prefix);
  84         if (length < sizeof(pw_prefix)) {
  85                 (void)strcpy(pw_prefix, new_prefix);
  86                 while (length > 0 && pw_prefix[length - 1] == '/')
  87                         pw_prefix[--length] = '\0';
  88                 return(0);
  89         }
  90         errno = ENAMETOOLONG;
  91         return(-1);
  92 }
  93
  94 static const char *
  95 pw_filename(const char *filename)
  96 {
  97         static char newfilename[MAXPATHLEN];
  98
  99         _DIAGASSERT(filename != NULL);
 100
 101         if (pw_prefix[0] == '\0')
 102                 return filename;
 103
 104         if (strlen(pw_prefix) + strlen(filename) < sizeof(newfilename))
 105                 return strcat(strcpy(newfilename, pw_prefix), filename);
 106
 107         errno = ENAMETOOLONG;
 108         return(NULL);
 109 }
 110
 111 int
 112 pw_lock(int retries)
 113 {
 114         const char *filename;
 115         int i, fd;
 116         mode_t old_mode;
 117         int oerrno;
 118
 119         /* Acquire the lock file. */
 120         filename = pw_filename(_PATH_MASTERPASSWD_LOCK);
 121         if (filename == NULL)
 122                 return(-1);
 123         old_mode = umask(0);
 124         fd = open(filename, O_WRONLY|O_CREAT|O_EXCL, 0600);
 125         for (i = 0; i < retries && fd < 0 && errno == EEXIST; i++) {
 126                 sleep(1);
 127                 fd = open(filename, O_WRONLY|O_CREAT|O_EXCL,
 128                           0600);
 129         }
 130         oerrno = errno;
 131         (void)umask(old_mode);
 132         errno = oerrno;
 133         return(fd);
 134 }
 135
 136 int
 137 pw_mkdb(username, secureonly)
 138         const char *username;
 139         int secureonly;
 140 {
 141         const char *args[9];
 142         int pstat, i;
 143         pid_t pid;
 144
 145         pid = vfork();
 146         if (pid == -1)
 147                 return -1;
 148
 149         if (pid == 0) {
 150                 args[0] = "pwd_mkdb";
 151                 args[1] = "-d";
 152                 args[2] = pw_prefix;
 153                 args[3] = "-pl";
 154                 i = 4;
 155
 156                 if (secureonly)
 157                         args[i++] = "-s";
 158                 if (username != NULL) {
 159                         args[i++] = "-u";
 160                         args[i++] = username;
 161                 }
 162
 163                 args[i++] = pw_filename(_PATH_MASTERPASSWD_LOCK);
 164                 args[i] = NULL;
 165                 execv(_PATH_PWD_MKDB, (char * const *)__UNCONST(args));
 166                 _exit(1);
 167         }
 168         pid = waitpid(pid, &pstat, 0);
 169         if (pid == -1) {
 170                 warn("error waiting for pid %lu", (unsigned long)pid);
 171                 return -1;
 172         }
 173         if (WIFEXITED(pstat)) {
 174                 if (WEXITSTATUS(pstat) != 0) {
 175                         warnx("pwd_mkdb exited with static %d",
 176                             WEXITSTATUS(pstat));
 177                         return -1;
 178                 }
 179         } else if (WIFSIGNALED(pstat)) {
 180                 warnx("pwd_mkdb exited with signal %d", WTERMSIG(pstat));
 181                 return -1;
 182         }
 183         return 0;
 184 }
 185
 186 int
 187 pw_abort(void)
 188 {
 189         const char *filename;
 190
 191         filename = pw_filename(_PATH_MASTERPASSWD_LOCK);
 192         return((filename == NULL) ? -1 : unlink(filename));
 193 }
 194
 195 /* Everything below this point is intended for the convenience of programs
 196  * which allow a user to interactively edit the passwd file.  Errors in the
 197  * routines below will cause the process to abort. */
 198
 199 static pid_t editpid = -1;
 200
 201 static void
 202 pw_cont(int sig)
 203 {
 204
 205         if (editpid != -1)
 206                 kill(editpid, sig);
 207 }
 208
 209 void
 210 pw_init(void)
 211 {
 212 #ifndef __minix
 213         struct rlimit rlim;
 214
 215         /* Unlimited resource limits. */
 216         rlim.rlim_cur = rlim.rlim_max = RLIM_INFINITY;
 217         (void)setrlimit(RLIMIT_CPU, &rlim);
 218         (void)setrlimit(RLIMIT_FSIZE, &rlim);
 219         (void)setrlimit(RLIMIT_STACK, &rlim);
 220         (void)setrlimit(RLIMIT_DATA, &rlim);
 221         (void)setrlimit(RLIMIT_RSS, &rlim);
 222
 223         /* Don't drop core (not really necessary, but GP's). */
 224         rlim.rlim_cur = rlim.rlim_max = 0;
 225         (void)setrlimit(RLIMIT_CORE, &rlim);
 226 #endif
 227
 228         /* Turn off signals. */
 229         (void)signal(SIGALRM, SIG_IGN);
 230         (void)signal(SIGHUP, SIG_IGN);
 231         (void)signal(SIGINT, SIG_IGN);
 232         (void)signal(SIGPIPE, SIG_IGN);
 233         (void)signal(SIGQUIT, SIG_IGN);
 234         (void)signal(SIGTERM, SIG_IGN);
 235         (void)signal(SIGCONT, pw_cont);
 236 }
 237
 238 void
 239 pw_edit(int notsetuid, const char *filename)
 240 {
 241         int pstat;
 242         char *p;
 243         const char * volatile editor;
 244         const char *argp[] = { "sh", "-c", NULL, NULL };
 245
 246         if (filename == NULL)
 247                 filename = _PATH_MASTERPASSWD_LOCK;
 248
 249         filename = pw_filename(filename);
 250         if (filename == NULL)
 251                 return;
 252
 253         if ((editor = getenv("EDITOR")) == NULL)
 254                 editor = _PATH_VI;
 255
 256         p = malloc(strlen(editor) + 1 + strlen(filename) + 1);
 257         if (p == NULL)
 258                 return;
 259
 260         sprintf(p, "%s %s", editor, filename);
 261         argp[2] = p;
 262
 263         switch(editpid = vfork()) {
 264         case -1:
 265                 free(p);
 266                 return;
 267         case 0:
 268                 if (notsetuid) {
 269                         setgid(getgid());
 270                         setuid(getuid());
 271                 }
 272                 execvp(_PATH_BSHELL, (char *const *)__UNCONST(argp));
 273                 _exit(1);
 274         }
 275
 276         free(p);
 277
 278         for (;;) {
 279                 editpid = waitpid(editpid, (int *)&pstat, WUNTRACED);
 280                 if (editpid == -1)
 281                         pw_error(editor, 1, 1);
 282                 else if (WIFSTOPPED(pstat))
 283                         raise(WSTOPSIG(pstat));
 284                 else if (WIFEXITED(pstat) && WEXITSTATUS(pstat) == 0)
 285                         break;
 286                 else
 287                         pw_error(editor, 1, 1);
 288         }
 289         editpid = -1;
 290 }
 291
 292 void
 293 pw_prompt(void)
 294 {
 295         int c;
 296
 297         (void)printf("re-edit the password file? [y]: ");
 298         (void)fflush(stdout);
 299         c = getchar();
 300         if (c != EOF && c != '\n')
 301                 while (getchar() != '\n');
 302         if (c == 'n')
 303                 pw_error(NULL, 0, 0);
 304 }
 305
 306 /* for use in pw_copy(). Compare a pw entry to a pw struct. */
 307 /* returns a character string labelling the miscompared field or 0 */
 308 static const char *
 309 pw_equal(char *buf, struct passwd *pw)
 310 {
 311         struct passwd buf_pw;
 312         size_t len;
 313
 314         _DIAGASSERT(buf != NULL);
 315         _DIAGASSERT(pw != NULL);
 316
 317         len = strlen (buf);
 318         if (buf[len-1] == '\n')
 319                 buf[len-1] = '\0';
 320         if (!pw_scan(buf, &buf_pw, NULL))
 321                 return "corrupt line";
 322         if (strcmp(pw->pw_name, buf_pw.pw_name) != 0)
 323                 return "name";
 324         if (pw->pw_uid != buf_pw.pw_uid)
 325                 return "uid";
 326         if (pw->pw_gid != buf_pw.pw_gid)
 327                 return "gid";
 328         if (strcmp( pw->pw_class, buf_pw.pw_class) != 0)
 329                 return "class";
 330         if (pw->pw_change != buf_pw.pw_change)
 331                 return "change";
 332         if (pw->pw_expire != buf_pw.pw_expire)
 333                 return "expire";
 334         if (strcmp( pw->pw_gecos, buf_pw.pw_gecos) != 0)
 335                 return "gecos";
 336         if (strcmp( pw->pw_dir, buf_pw.pw_dir) != 0)
 337                 return "dir";
 338         if (strcmp( pw->pw_shell, buf_pw.pw_shell) != 0)
 339                 return "shell";
 340         return (char *)0;
 341 }
 342
 343 void
 344 pw_copy(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw)
 345 {
 346         char errbuf[200];
 347         int rv;
 348
 349         rv = pw_copyx(ffd, tfd, pw, old_pw, errbuf, sizeof(errbuf));
 350         if (rv == 0) {
 351                 warnx("%s", errbuf);
 352                 pw_error(NULL, 0, 1);
 353         }
 354 }
 355
 356 static void
 357 pw_print(FILE *to, const struct passwd *pw)
 358 {
 359         (void)fprintf(to, "%s:%s:%d:%d:%s:%lld:%lld:%s:%s:%s\n",
 360             pw->pw_name, pw->pw_passwd, pw->pw_uid, pw->pw_gid,
 361             pw->pw_class, (long long)pw->pw_change,
 362             (long long)pw->pw_expire,
 363             pw->pw_gecos, pw->pw_dir, pw->pw_shell);
 364 }
 365
 366 int
 367 pw_copyx(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw,
 368     char *errbuf, size_t errbufsz)
 369 {
 370         const char *filename;
 371         char mpwd[MAXPATHLEN], mpwdl[MAXPATHLEN], *p, buf[8192];
 372         FILE *from, *to;
 373         int done;
 374
 375         _DIAGASSERT(pw != NULL);
 376         _DIAGASSERT(errbuf != NULL);
 377         /* old_pw may be NULL */
 378
 379         if ((filename = pw_filename(_PATH_MASTERPASSWD)) == NULL) {
 380                 snprintf(errbuf, errbufsz, "%s: %s", pw_prefix,
 381                     strerror(errno));
 382                 return (0);
 383         }
 384         (void)strcpy(mpwd, filename);
 385         if ((filename = pw_filename(_PATH_MASTERPASSWD_LOCK)) == NULL) {
 386                 snprintf(errbuf, errbufsz, "%s: %s", pw_prefix,
 387                     strerror(errno));
 388                 return (0);
 389         }
 390         (void)strcpy(mpwdl, filename);
 391
 392         if (!(from = fdopen(ffd, "r"))) {
 393                 snprintf(errbuf, errbufsz, "%s: %s", mpwd, strerror(errno));
 394                 return (0);
 395         }
 396         if (!(to = fdopen(tfd, "w"))) {
 397                 snprintf(errbuf, errbufsz, "%s: %s", mpwdl, strerror(errno));
 398                 (void)fclose(from);
 399                 return (0);
 400         }
 401
 402         for (done = 0; fgets(buf, (int)sizeof(buf), from);) {
 403                 const char *neq;
 404                 if (!strchr(buf, '\n')) {
 405                         snprintf(errbuf, errbufsz, "%s: line too long", mpwd);
 406                         (void)fclose(from);
 407                         (void)fclose(to);
 408                         return (0);
 409                 }
 410                 if (done) {
 411                         (void)fprintf(to, "%s", buf);
 412                         if (ferror(to)) {
 413                                 snprintf(errbuf, errbufsz, "%s",
 414                                     strerror(errno));
 415                                 (void)fclose(from);
 416                                 (void)fclose(to);
 417                                 return (0);
 418                         }
 419                         continue;
 420                 }
 421                 if (!(p = strchr(buf, ':'))) {
 422                         snprintf(errbuf, errbufsz, "%s: corrupted entry", mpwd);
 423                         (void)fclose(from);
 424                         (void)fclose(to);
 425                         return (0);
 426                 }
 427                 *p = '\0';
 428                 if (strcmp(buf, pw->pw_name)) {
 429                         *p = ':';
 430                         (void)fprintf(to, "%s", buf);
 431                         if (ferror(to)) {
 432                                 snprintf(errbuf, errbufsz, "%s",
 433                                     strerror(errno));
 434                                 (void)fclose(from);
 435                                 (void)fclose(to);
 436                                 return (0);
 437                         }
 438                         continue;
 439                 }
 440                 *p = ':';
 441                 if (old_pw && (neq = pw_equal(buf, old_pw)) != NULL) {
 442                         if (strcmp(neq, "corrupt line") == 0)
 443                                 (void)snprintf(errbuf, errbufsz,
 444                                     "%s: entry %s corrupted", mpwd,
 445                                     pw->pw_name);
 446                         else
 447                                 (void)snprintf(errbuf, errbufsz,
 448                                     "%s: entry %s inconsistent %s",
 449                                     mpwd, pw->pw_name, neq);
 450                         (void)fclose(from);
 451                         (void)fclose(to);
 452                         return (0);
 453                 }
 454                 pw_print(to, pw);
 455                 done = 1;
 456                 if (ferror(to)) {
 457                         snprintf(errbuf, errbufsz, "%s", strerror(errno));
 458                         (void)fclose(from);
 459                         (void)fclose(to);
 460                         return (0);
 461                 }
 462         }
 463         /* Only append a new entry if real uid is root! */
 464         if (!done) {
 465                 if (getuid() == 0) {
 466                         pw_print(to, pw);
 467                         done = 1;
 468                 } else {
 469                         snprintf(errbuf, errbufsz,
 470                             "%s: changes not made, no such entry", mpwd);
 471                 }
 472         }
 473
 474         if (ferror(to)) {
 475                 snprintf(errbuf, errbufsz, "%s", strerror(errno));
 476                 (void)fclose(from);
 477                 (void)fclose(to);
 478                 return (0);
 479         }
 480         (void)fclose(from);
 481         (void)fclose(to);
 482
 483         return (done);
 484 }
 485
 486 void
 487 pw_error(const char *name, int error, int eval)
 488 {
 489
 490         if (error) {
 491                 if (name)
 492                         warn("%s", name);
 493                 else
 494                         warn(NULL);
 495         }
 496
 497         warnx("%s%s: unchanged", pw_prefix, _PATH_MASTERPASSWD);
 498         pw_abort();
 499         exit(eval);
 500 }
 501
 502 /* Removes head and/or tail spaces. */
 503 static void
 504 trim_whitespace(char *line)
 505 {
 506         char *p;
 507
 508         _DIAGASSERT(line != NULL);
 509
 510         /* Remove leading spaces */
 511         p = line;
 512         while (isspace((unsigned char) *p))
 513                 p++;
 514         memmove(line, p, strlen(p) + 1);
 515
 516         /* Remove trailing spaces */
 517         p = line + strlen(line) - 1;
 518         while (isspace((unsigned char) *p))
 519                 p--;
 520         *(p + 1) = '\0';
 521 }
 522
 523
 524 /* Get one line, remove spaces from front and tail */
 525 static int
 526 read_line(FILE *fp, char *line, int max)
 527 {
 528         char   *p;
 529
 530         _DIAGASSERT(fp != NULL);
 531         _DIAGASSERT(line != NULL);
 532
 533         /* Read one line of config */
 534         if (fgets(line, max, fp) == NULL)
 535                 return (0);
 536
 537         if ((p = strchr(line, '\n')) == NULL) {
 538                 warnx("line too long");
 539                 return (0);
 540         }
 541         *p = '\0';
 542
 543         /* Remove comments */
 544         if ((p = strchr(line, '#')) != NULL)
 545                 *p = '\0';
 546
 547         trim_whitespace(line);
 548         return (1);
 549 }
 550
 551 static const char *
 552 pw_default(const char *option)
 553 {
 554         static const char *options[][2] = {
 555                 { "localcipher",        "old" },
 556                 { "ypcipher",           "old" },
 557         };
 558         size_t i;
 559
 560         _DIAGASSERT(option != NULL);
 561         for (i = 0; i < sizeof(options) / sizeof(options[0]); i++)
 562                 if (strcmp(options[i][0], option) == 0)
 563                         return (options[i][1]);
 564
 565         return (NULL);
 566 }
 567
 568 /*
 569  * Retrieve password information from the /etc/passwd.conf file, at the
 570  * moment this is only for choosing the cipher to use.  It could easily be
 571  * used for other authentication methods as well.
 572  */
 573 void
 574 pw_getconf(char *data, size_t max, const char *key, const char *option)
 575 {
 576         FILE *fp;
 577         char line[LINE_MAX], *p, *p2;
 578         static char result[LINE_MAX];
 579         int got, found;
 580         const char *cp;
 581
 582         _DIAGASSERT(data != NULL);
 583         _DIAGASSERT(key != NULL);
 584         _DIAGASSERT(option != NULL);
 585
 586         got = 0;
 587         found = 0;
 588         result[0] = '\0';
 589
 590         if ((fp = fopen(_PATH_PASSWD_CONF, "r")) == NULL) {
 591                 if ((cp = pw_default(option)) != NULL)
 592                         strlcpy(data, cp, max);
 593                 else
 594                         data[0] = '\0';
 595                 return;
 596         }
 597
 598         while (!found && (got || read_line(fp, line, LINE_MAX))) {
 599                 got = 0;
 600
 601                 if (strncmp(key, line, strlen(key)) != 0 ||
 602                     line[strlen(key)] != ':')
 603                         continue;
 604
 605                 /* Now we found our specified key */
 606                 while (read_line(fp, line, LINE_MAX)) {
 607                         /* Leaving key field */
 608                         if (line[0] != '\0' && strchr(line + 1, ':') != NULL) {
 609                                 got = 1;
 610                                 break;
 611                         }
 612                         p2 = line;
 613                         if ((p = strsep(&p2, "=")) == NULL || p2 == NULL)
 614                                 continue;
 615                         trim_whitespace(p);
 616
 617                         if (!strncmp(p, option, strlen(option))) {
 618                                 trim_whitespace(p2);
 619                                 strcpy(result, p2);
 620                                 found = 1;
 621                                 break;
 622                         }
 623                 }
 624         }
 625         fclose(fp);
 626
 627         if (!found)
 628                 errno = ENOENT;
 629         if (!got)
 630                 errno = ENOTDIR;
 631
 632         /*
 633          * If we got no result and were looking for a default
 634          * value, try hard coded defaults.
 635          */
 636
 637         if (strlen(result) == 0 && strcmp(key, "default") == 0 &&
 638             (cp = pw_default(option)) != NULL)
 639                 strlcpy(data, cp, max);
 640         else
 641                 strlcpy(data, result, max);
 642 }
 643
 644 void
 645 pw_getpwconf(char *data, size_t max, const struct passwd *pwd,
 646     const char *option)
 647 {
 648         char grpkey[LINE_MAX];
 649         struct group grs, *grp;
 650         char grbuf[1024];
 651
 652         pw_getconf(data, max, pwd->pw_name, option);
 653
 654         /* Try to find an entry for the group */
 655         if (*data == '\0') {
 656                 (void)getgrgid_r(pwd->pw_gid, &grs, grbuf, sizeof(grbuf), &grp);
 657                 if (grp != NULL) {
 658                         (void)snprintf(grpkey, sizeof(grpkey), ":%s",
 659                             grp->gr_name);
 660                         pw_getconf(data, max, grpkey, option);
 661                 }
 662                 if (*data == '\0')
 663                         pw_getconf(data, max, "default", option);
 664         }
 665 }