lib/libutil/passwd.c

   1 /*      $NetBSD: passwd.c,v 1.47 2009/01/11 02:57:17 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 1.47 2009/01/11 02:57:17 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] = "-p";
 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 || !WIFEXITED(pstat) || WEXITSTATUS(pstat) != 0)
 170                 return(-1);
 171         return(0);
 172 }
 173
 174 int
 175 pw_abort(void)
 176 {
 177         const char *filename;
 178
 179         filename = pw_filename(_PATH_MASTERPASSWD_LOCK);
 180         return((filename == NULL) ? -1 : unlink(filename));
 181 }
 182
 183 /* Everything below this point is intended for the convenience of programs
 184  * which allow a user to interactively edit the passwd file.  Errors in the
 185  * routines below will cause the process to abort. */
 186
 187 static pid_t editpid = -1;
 188
 189 static void
 190 pw_cont(int sig)
 191 {
 192
 193         if (editpid != -1)
 194                 kill(editpid, sig);
 195 }
 196
 197 void
 198 pw_init(void)
 199 {
 200         struct rlimit rlim;
 201
 202         /* Unlimited resource limits. */
 203         rlim.rlim_cur = rlim.rlim_max = RLIM_INFINITY;
 204         (void)setrlimit(RLIMIT_CPU, &rlim);
 205         (void)setrlimit(RLIMIT_FSIZE, &rlim);
 206         (void)setrlimit(RLIMIT_STACK, &rlim);
 207         (void)setrlimit(RLIMIT_DATA, &rlim);
 208         (void)setrlimit(RLIMIT_RSS, &rlim);
 209
 210         /* Don't drop core (not really necessary, but GP's). */
 211         rlim.rlim_cur = rlim.rlim_max = 0;
 212         (void)setrlimit(RLIMIT_CORE, &rlim);
 213
 214         /* Turn off signals. */
 215         (void)signal(SIGALRM, SIG_IGN);
 216         (void)signal(SIGHUP, SIG_IGN);
 217         (void)signal(SIGINT, SIG_IGN);
 218         (void)signal(SIGPIPE, SIG_IGN);
 219         (void)signal(SIGQUIT, SIG_IGN);
 220         (void)signal(SIGTERM, SIG_IGN);
 221         (void)signal(SIGCONT, pw_cont);
 222 }
 223
 224 void
 225 pw_edit(int notsetuid, const char *filename)
 226 {
 227         int pstat;
 228         char *p;
 229         const char * volatile editor;
 230         const char *argp[] = { "sh", "-c", NULL, NULL };
 231
 232         if (filename == NULL)
 233                 filename = _PATH_MASTERPASSWD_LOCK;
 234
 235         filename = pw_filename(filename);
 236         if (filename == NULL)
 237                 return;
 238
 239         if ((editor = getenv("EDITOR")) == NULL)
 240                 editor = _PATH_VI;
 241
 242         p = malloc(strlen(editor) + 1 + strlen(filename) + 1);
 243         if (p == NULL)
 244                 return;
 245
 246         sprintf(p, "%s %s", editor, filename);
 247         argp[2] = p;
 248
 249         switch(editpid = vfork()) {
 250         case -1:
 251                 free(p);
 252                 return;
 253         case 0:
 254                 if (notsetuid) {
 255                         setgid(getgid());
 256                         setuid(getuid());
 257                 }
 258                 execvp(_PATH_BSHELL, (char *const *)__UNCONST(argp));
 259                 _exit(1);
 260         }
 261
 262         free(p);
 263
 264         for (;;) {
 265                 editpid = waitpid(editpid, (int *)&pstat, WUNTRACED);
 266                 if (editpid == -1)
 267                         pw_error(editor, 1, 1);
 268                 else if (WIFSTOPPED(pstat))
 269                         raise(WSTOPSIG(pstat));
 270                 else if (WIFEXITED(pstat) && WEXITSTATUS(pstat) == 0)
 271                         break;
 272                 else
 273                         pw_error(editor, 1, 1);
 274         }
 275         editpid = -1;
 276 }
 277
 278 void
 279 pw_prompt(void)
 280 {
 281         int c;
 282
 283         (void)printf("re-edit the password file? [y]: ");
 284         (void)fflush(stdout);
 285         c = getchar();
 286         if (c != EOF && c != '\n')
 287                 while (getchar() != '\n');
 288         if (c == 'n')
 289                 pw_error(NULL, 0, 0);
 290 }
 291
 292 /* for use in pw_copy(). Compare a pw entry to a pw struct. */
 293 /* returns a character string labelling the miscompared field or 0 */
 294 static const char *
 295 pw_equal(char *buf, struct passwd *pw)
 296 {
 297         struct passwd buf_pw;
 298         size_t len;
 299
 300         _DIAGASSERT(buf != NULL);
 301         _DIAGASSERT(pw != NULL);
 302
 303         len = strlen (buf);
 304         if (buf[len-1] == '\n')
 305                 buf[len-1] = '\0';
 306         if (!pw_scan(buf, &buf_pw, NULL))
 307                 return "corrupt line";
 308         if (strcmp(pw->pw_name, buf_pw.pw_name) != 0)
 309                 return "name";
 310         if (pw->pw_uid != buf_pw.pw_uid)
 311                 return "uid";
 312         if (pw->pw_gid != buf_pw.pw_gid)
 313                 return "gid";
 314         if (strcmp( pw->pw_class, buf_pw.pw_class) != 0)
 315                 return "class";
 316         if (pw->pw_change != buf_pw.pw_change)
 317                 return "change";
 318         if (pw->pw_expire != buf_pw.pw_expire)
 319                 return "expire";
 320         if (strcmp( pw->pw_gecos, buf_pw.pw_gecos) != 0)
 321                 return "gecos";
 322         if (strcmp( pw->pw_dir, buf_pw.pw_dir) != 0)
 323                 return "dir";
 324         if (strcmp( pw->pw_shell, buf_pw.pw_shell) != 0)
 325                 return "shell";
 326         return (char *)0;
 327 }
 328
 329 void
 330 pw_copy(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw)
 331 {
 332         char errbuf[200];
 333         int rv;
 334
 335         rv = pw_copyx(ffd, tfd, pw, old_pw, errbuf, sizeof(errbuf));
 336         if (rv == 0) {
 337                 warnx("%s", errbuf);
 338                 pw_error(NULL, 0, 1);
 339         }
 340 }
 341
 342 static void
 343 pw_print(FILE *to, const struct passwd *pw)
 344 {
 345         (void)fprintf(to, "%s:%s:%d:%d:%s:%lld:%lld:%s:%s:%s\n",
 346             pw->pw_name, pw->pw_passwd, pw->pw_uid, pw->pw_gid,
 347             pw->pw_class, (long long)pw->pw_change,
 348             (long long)pw->pw_expire,
 349             pw->pw_gecos, pw->pw_dir, pw->pw_shell);
 350 }
 351
 352 int
 353 pw_copyx(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw,
 354     char *errbuf, size_t errbufsz)
 355 {
 356         const char *filename;
 357         char mpwd[MAXPATHLEN], mpwdl[MAXPATHLEN], *p, buf[8192];
 358         FILE *from, *to;
 359         int done;
 360
 361         _DIAGASSERT(pw != NULL);
 362         _DIAGASSERT(errbuf != NULL);
 363         /* old_pw may be NULL */
 364
 365         if ((filename = pw_filename(_PATH_MASTERPASSWD)) == NULL) {
 366                 snprintf(errbuf, errbufsz, "%s: %s", pw_prefix,
 367                     strerror(errno));
 368                 return (0);
 369         }
 370         (void)strcpy(mpwd, filename);
 371         if ((filename = pw_filename(_PATH_MASTERPASSWD_LOCK)) == NULL) {
 372                 snprintf(errbuf, errbufsz, "%s: %s", pw_prefix,
 373                     strerror(errno));
 374                 return (0);
 375         }
 376         (void)strcpy(mpwdl, filename);
 377
 378         if (!(from = fdopen(ffd, "r"))) {
 379                 snprintf(errbuf, errbufsz, "%s: %s", mpwd, strerror(errno));
 380                 return (0);
 381         }
 382         if (!(to = fdopen(tfd, "w"))) {
 383                 snprintf(errbuf, errbufsz, "%s: %s", mpwdl, strerror(errno));
 384                 (void)fclose(from);
 385                 return (0);
 386         }
 387
 388         for (done = 0; fgets(buf, (int)sizeof(buf), from);) {
 389                 const char *neq;
 390                 if (!strchr(buf, '\n')) {
 391                         snprintf(errbuf, errbufsz, "%s: line too long", mpwd);
 392                         (void)fclose(from);
 393                         (void)fclose(to);
 394                         return (0);
 395                 }
 396                 if (done) {
 397                         (void)fprintf(to, "%s", buf);
 398                         if (ferror(to)) {
 399                                 snprintf(errbuf, errbufsz, "%s",
 400                                     strerror(errno));
 401                                 (void)fclose(from);
 402                                 (void)fclose(to);
 403                                 return (0);
 404                         }
 405                         continue;
 406                 }
 407                 if (!(p = strchr(buf, ':'))) {
 408                         snprintf(errbuf, errbufsz, "%s: corrupted entry", mpwd);
 409                         (void)fclose(from);
 410                         (void)fclose(to);
 411                         return (0);
 412                 }
 413                 *p = '\0';
 414                 if (strcmp(buf, pw->pw_name)) {
 415                         *p = ':';
 416                         (void)fprintf(to, "%s", buf);
 417                         if (ferror(to)) {
 418                                 snprintf(errbuf, errbufsz, "%s",
 419                                     strerror(errno));
 420                                 (void)fclose(from);
 421                                 (void)fclose(to);
 422                                 return (0);
 423                         }
 424                         continue;
 425                 }
 426                 *p = ':';
 427                 if (old_pw && (neq = pw_equal(buf, old_pw)) != NULL) {
 428                         if (strcmp(neq, "corrupt line") == 0)
 429                                 (void)snprintf(errbuf, errbufsz,
 430                                     "%s: entry %s corrupted", mpwd,
 431                                     pw->pw_name);
 432                         else
 433                                 (void)snprintf(errbuf, errbufsz,
 434                                     "%s: entry %s inconsistent %s",
 435                                     mpwd, pw->pw_name, neq);
 436                         (void)fclose(from);
 437                         (void)fclose(to);
 438                         return (0);
 439                 }
 440                 pw_print(to, pw);
 441                 done = 1;
 442                 if (ferror(to)) {
 443                         snprintf(errbuf, errbufsz, "%s", strerror(errno));
 444                         (void)fclose(from);
 445                         (void)fclose(to);
 446                         return (0);
 447                 }
 448         }
 449         /* Only append a new entry if real uid is root! */
 450         if (!done) {
 451                 if (getuid() == 0) {
 452                         pw_print(to, pw);
 453                         done = 1;
 454                 } else {
 455                         snprintf(errbuf, errbufsz,
 456                             "%s: changes not made, no such entry", mpwd);
 457                 }
 458         }
 459
 460         if (ferror(to)) {
 461                 snprintf(errbuf, errbufsz, "%s", strerror(errno));
 462                 (void)fclose(from);
 463                 (void)fclose(to);
 464                 return (0);
 465         }
 466         (void)fclose(from);
 467         (void)fclose(to);
 468
 469         return (done);
 470 }
 471
 472 void
 473 pw_error(const char *name, int error, int eval)
 474 {
 475
 476         if (error) {
 477                 if (name)
 478                         warn("%s", name);
 479                 else
 480                         warn(NULL);
 481         }
 482
 483         warnx("%s%s: unchanged", pw_prefix, _PATH_MASTERPASSWD);
 484         pw_abort();
 485         exit(eval);
 486 }
 487
 488 /* Removes head and/or tail spaces. */
 489 static void
 490 trim_whitespace(char *line)
 491 {
 492         char *p;
 493
 494         _DIAGASSERT(line != NULL);
 495
 496         /* Remove leading spaces */
 497         p = line;
 498         while (isspace((unsigned char) *p))
 499                 p++;
 500         memmove(line, p, strlen(p) + 1);
 501
 502         /* Remove trailing spaces */
 503         p = line + strlen(line) - 1;
 504         while (isspace((unsigned char) *p))
 505                 p--;
 506         *(p + 1) = '\0';
 507 }
 508
 509
 510 /* Get one line, remove spaces from front and tail */
 511 static int
 512 read_line(FILE *fp, char *line, int max)
 513 {
 514         char   *p;
 515
 516         _DIAGASSERT(fp != NULL);
 517         _DIAGASSERT(line != NULL);
 518
 519         /* Read one line of config */
 520         if (fgets(line, max, fp) == NULL)
 521                 return (0);
 522
 523         if ((p = strchr(line, '\n')) == NULL) {
 524                 warnx("line too long");
 525                 return (0);
 526         }
 527         *p = '\0';
 528
 529         /* Remove comments */
 530         if ((p = strchr(line, '#')) != NULL)
 531                 *p = '\0';
 532
 533         trim_whitespace(line);
 534         return (1);
 535 }
 536
 537 static const char *
 538 pw_default(const char *option)
 539 {
 540         static const char *options[][2] = {
 541                 { "localcipher",        "old" },
 542                 { "ypcipher",           "old" },
 543         };
 544         size_t i;
 545
 546         _DIAGASSERT(option != NULL);
 547         for (i = 0; i < sizeof(options) / sizeof(options[0]); i++)
 548                 if (strcmp(options[i][0], option) == 0)
 549                         return (options[i][1]);
 550
 551         return (NULL);
 552 }
 553
 554 /*
 555  * Retrieve password information from the /etc/passwd.conf file, at the
 556  * moment this is only for choosing the cipher to use.  It could easily be
 557  * used for other authentication methods as well.
 558  */
 559 void
 560 pw_getconf(char *data, size_t max, const char *key, const char *option)
 561 {
 562         FILE *fp;
 563         char line[LINE_MAX], *p, *p2;
 564         static char result[LINE_MAX];
 565         int got, found;
 566         const char *cp;
 567
 568         _DIAGASSERT(data != NULL);
 569         _DIAGASSERT(key != NULL);
 570         _DIAGASSERT(option != NULL);
 571
 572         got = 0;
 573         found = 0;
 574         result[0] = '\0';
 575
 576         if ((fp = fopen(_PATH_PASSWD_CONF, "r")) == NULL) {
 577                 if ((cp = pw_default(option)) != NULL)
 578                         strlcpy(data, cp, max);
 579                 else
 580                         data[0] = '\0';
 581                 return;
 582         }
 583
 584         while (!found && (got || read_line(fp, line, LINE_MAX))) {
 585                 got = 0;
 586
 587                 if (strncmp(key, line, strlen(key)) != 0 ||
 588                     line[strlen(key)] != ':')
 589                         continue;
 590
 591                 /* Now we found our specified key */
 592                 while (read_line(fp, line, LINE_MAX)) {
 593                         /* Leaving key field */
 594                         if (line[0] != '\0' && strchr(line + 1, ':') != NULL) {
 595                                 got = 1;
 596                                 break;
 597                         }
 598                         p2 = line;
 599                         if ((p = strsep(&p2, "=")) == NULL || p2 == NULL)
 600                                 continue;
 601                         trim_whitespace(p);
 602
 603                         if (!strncmp(p, option, strlen(option))) {
 604                                 trim_whitespace(p2);
 605                                 strcpy(result, p2);
 606                                 found = 1;
 607                                 break;
 608                         }
 609                 }
 610         }
 611         fclose(fp);
 612
 613         if (!found)
 614                 errno = ENOENT;
 615         if (!got)
 616                 errno = ENOTDIR;
 617
 618         /*
 619          * If we got no result and were looking for a default
 620          * value, try hard coded defaults.
 621          */
 622
 623         if (strlen(result) == 0 && strcmp(key, "default") == 0 &&
 624             (cp = pw_default(option)) != NULL)
 625                 strlcpy(data, cp, max);
 626         else
 627                 strlcpy(data, result, max);
 628 }
 629
 630 void
 631 pw_getpwconf(char *data, size_t max, const struct passwd *pwd,
 632     const char *option)
 633 {
 634         char grpkey[LINE_MAX];
 635         struct group grs, *grp;
 636         char grbuf[1024];
 637
 638         pw_getconf(data, max, pwd->pw_name, option);
 639
 640         /* Try to find an entry for the group */
 641         if (*data == '\0') {
 642                 (void)getgrgid_r(pwd->pw_gid, &grs, grbuf, sizeof(grbuf), &grp);
 643                 if (grp != NULL) {
 644                         (void)snprintf(grpkey, sizeof(grpkey), ":%s",
 645                             grp->gr_name);
 646                         pw_getconf(data, max, grpkey, option);
 647                 }
 648                 if (*data == '\0')
 649                         pw_getconf(data, max, "default", option);
 650         }
 651 }