lib/libutil/passwd.c

   1 /*      $NetBSD: passwd.c,v 1.52 2012/06/25 22:32:47 abs 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 1.52 2012/06/25 22:32:47 abs 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(const char *username, int secureonly)
 138 {
 139         const char *args[9];
 140         int pstat, i;
 141         pid_t pid;
 142
 143         pid = vfork();
 144         if (pid == -1)
 145                 return -1;
 146
 147         if (pid == 0) {
 148                 args[0] = "pwd_mkdb";
 149                 args[1] = "-d";
 150                 args[2] = pw_prefix;
 151                 args[3] = "-pl";
 152                 i = 4;
 153
 154                 if (secureonly)
 155                         args[i++] = "-s";
 156                 if (username != NULL) {
 157                         args[i++] = "-u";
 158                         args[i++] = username;
 159                 }
 160
 161                 args[i++] = pw_filename(_PATH_MASTERPASSWD_LOCK);
 162                 args[i] = NULL;
 163                 execv(_PATH_PWD_MKDB, (char * const *)__UNCONST(args));
 164                 _exit(1);
 165         }
 166         pid = waitpid(pid, &pstat, 0);
 167         if (pid == -1) {
 168                 warn("error waiting for pid %lu", (unsigned long)pid);
 169                 return -1;
 170         }
 171         if (WIFEXITED(pstat)) {
 172                 if (WEXITSTATUS(pstat) != 0) {
 173                         warnx("pwd_mkdb exited with status %d",
 174                             WEXITSTATUS(pstat));
 175                         return -1;
 176                 }
 177         } else if (WIFSIGNALED(pstat)) {
 178                 warnx("pwd_mkdb exited with signal %d", WTERMSIG(pstat));
 179                 return -1;
 180         }
 181         return 0;
 182 }
 183
 184 int
 185 pw_abort(void)
 186 {
 187         const char *filename;
 188
 189         filename = pw_filename(_PATH_MASTERPASSWD_LOCK);
 190         return((filename == NULL) ? -1 : unlink(filename));
 191 }
 192
 193 /* Everything below this point is intended for the convenience of programs
 194  * which allow a user to interactively edit the passwd file.  Errors in the
 195  * routines below will cause the process to abort. */
 196
 197 static pid_t editpid = -1;
 198
 199 static void
 200 pw_cont(int sig)
 201 {
 202
 203         if (editpid != -1)
 204                 kill(editpid, sig);
 205 }
 206
 207 void
 208 pw_init(void)
 209 {
 210         struct rlimit rlim;
 211
 212         /* Unlimited resource limits. */
 213         rlim.rlim_cur = rlim.rlim_max = RLIM_INFINITY;
 214         (void)setrlimit(RLIMIT_CPU, &rlim);
 215         (void)setrlimit(RLIMIT_FSIZE, &rlim);
 216         (void)setrlimit(RLIMIT_STACK, &rlim);
 217         (void)setrlimit(RLIMIT_DATA, &rlim);
 218         (void)setrlimit(RLIMIT_RSS, &rlim);
 219
 220         /* Don't drop core (not really necessary, but GP's). */
 221         rlim.rlim_cur = rlim.rlim_max = 0;
 222         (void)setrlimit(RLIMIT_CORE, &rlim);
 223
 224         /* Turn off signals. */
 225         (void)signal(SIGALRM, SIG_IGN);
 226         (void)signal(SIGHUP, SIG_IGN);
 227         (void)signal(SIGINT, SIG_IGN);
 228         (void)signal(SIGPIPE, SIG_IGN);
 229         (void)signal(SIGQUIT, SIG_IGN);
 230         (void)signal(SIGTERM, SIG_IGN);
 231         (void)signal(SIGCONT, pw_cont);
 232 }
 233
 234 void
 235 pw_edit(int notsetuid, const char *filename)
 236 {
 237         int pstat;
 238         char *p;
 239         const char * volatile editor;
 240         const char *argp[] = { "sh", "-c", NULL, NULL };
 241
 242         if (filename == NULL)
 243                 filename = _PATH_MASTERPASSWD_LOCK;
 244
 245         filename = pw_filename(filename);
 246         if (filename == NULL)
 247                 return;
 248
 249         if ((editor = getenv("EDITOR")) == NULL)
 250                 editor = _PATH_VI;
 251
 252         p = malloc(strlen(editor) + 1 + strlen(filename) + 1);
 253         if (p == NULL)
 254                 return;
 255
 256         sprintf(p, "%s %s", editor, filename);
 257         argp[2] = p;
 258
 259         switch(editpid = vfork()) {
 260         case -1:
 261                 free(p);
 262                 return;
 263         case 0:
 264                 if (notsetuid) {
 265                         setgid(getgid());
 266                         setuid(getuid());
 267                 }
 268                 execvp(_PATH_BSHELL, (char *const *)__UNCONST(argp));
 269                 _exit(1);
 270         }
 271
 272         free(p);
 273
 274         for (;;) {
 275                 editpid = waitpid(editpid, (int *)&pstat, WUNTRACED);
 276                 if (editpid == -1)
 277                         pw_error(editor, 1, 1);
 278                 else if (WIFSTOPPED(pstat))
 279                         raise(WSTOPSIG(pstat));
 280                 else if (WIFEXITED(pstat) && WEXITSTATUS(pstat) == 0)
 281                         break;
 282                 else
 283                         pw_error(editor, 1, 1);
 284         }
 285         editpid = -1;
 286 }
 287
 288 void
 289 pw_prompt(void)
 290 {
 291         int c;
 292
 293         (void)printf("re-edit the password file? [y]: ");
 294         (void)fflush(stdout);
 295         c = getchar();
 296         if (c != EOF && c != '\n')
 297                 while (getchar() != '\n');
 298         if (c == 'n')
 299                 pw_error(NULL, 0, 0);
 300 }
 301
 302 /* for use in pw_copy(). Compare a pw entry to a pw struct. */
 303 /* returns a character string labelling the miscompared field or 0 */
 304 static const char *
 305 pw_equal(char *buf, struct passwd *pw)
 306 {
 307         struct passwd buf_pw;
 308         size_t len;
 309
 310         _DIAGASSERT(buf != NULL);
 311         _DIAGASSERT(pw != NULL);
 312
 313         len = strlen (buf);
 314         if (buf[len-1] == '\n')
 315                 buf[len-1] = '\0';
 316         if (!pw_scan(buf, &buf_pw, NULL))
 317                 return "corrupt line";
 318         if (strcmp(pw->pw_name, buf_pw.pw_name) != 0)
 319                 return "name";
 320         if (pw->pw_uid != buf_pw.pw_uid)
 321                 return "uid";
 322         if (pw->pw_gid != buf_pw.pw_gid)
 323                 return "gid";
 324         if (strcmp( pw->pw_class, buf_pw.pw_class) != 0)
 325                 return "class";
 326         if (pw->pw_change != buf_pw.pw_change)
 327                 return "change";
 328         if (pw->pw_expire != buf_pw.pw_expire)
 329                 return "expire";
 330         if (strcmp( pw->pw_gecos, buf_pw.pw_gecos) != 0)
 331                 return "gecos";
 332         if (strcmp( pw->pw_dir, buf_pw.pw_dir) != 0)
 333                 return "dir";
 334         if (strcmp( pw->pw_shell, buf_pw.pw_shell) != 0)
 335                 return "shell";
 336         return (char *)0;
 337 }
 338
 339 void
 340 pw_copy(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw)
 341 {
 342         char errbuf[200];
 343         int rv;
 344
 345         rv = pw_copyx(ffd, tfd, pw, old_pw, errbuf, sizeof(errbuf));
 346         if (rv == 0) {
 347                 warnx("%s", errbuf);
 348                 pw_error(NULL, 0, 1);
 349         }
 350 }
 351
 352 static void
 353 pw_print(FILE *to, const struct passwd *pw)
 354 {
 355         (void)fprintf(to, "%s:%s:%d:%d:%s:%lld:%lld:%s:%s:%s\n",
 356             pw->pw_name, pw->pw_passwd, pw->pw_uid, pw->pw_gid,
 357             pw->pw_class, (long long)pw->pw_change,
 358             (long long)pw->pw_expire,
 359             pw->pw_gecos, pw->pw_dir, pw->pw_shell);
 360 }
 361
 362 int
 363 pw_copyx(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw,
 364     char *errbuf, size_t errbufsz)
 365 {
 366         const char *filename;
 367         char mpwd[MAXPATHLEN], mpwdl[MAXPATHLEN], *p, buf[8192];
 368         FILE *from, *to;
 369         int done;
 370
 371         _DIAGASSERT(pw != NULL);
 372         _DIAGASSERT(errbuf != NULL);
 373         /* old_pw may be NULL */
 374
 375         if ((filename = pw_filename(_PATH_MASTERPASSWD)) == NULL) {
 376                 snprintf(errbuf, errbufsz, "%s: %s", pw_prefix,
 377                     strerror(errno));
 378                 return (0);
 379         }
 380         (void)strcpy(mpwd, filename);
 381         if ((filename = pw_filename(_PATH_MASTERPASSWD_LOCK)) == NULL) {
 382                 snprintf(errbuf, errbufsz, "%s: %s", pw_prefix,
 383                     strerror(errno));
 384                 return (0);
 385         }
 386         (void)strcpy(mpwdl, filename);
 387
 388         if (!(from = fdopen(ffd, "r"))) {
 389                 snprintf(errbuf, errbufsz, "%s: %s", mpwd, strerror(errno));
 390                 return (0);
 391         }
 392         if (!(to = fdopen(tfd, "w"))) {
 393                 snprintf(errbuf, errbufsz, "%s: %s", mpwdl, strerror(errno));
 394                 (void)fclose(from);
 395                 return (0);
 396         }
 397
 398         for (done = 0; fgets(buf, (int)sizeof(buf), from);) {
 399                 const char *neq;
 400                 if (!strchr(buf, '\n')) {
 401                         snprintf(errbuf, errbufsz, "%s: line too long", mpwd);
 402                         (void)fclose(from);
 403                         (void)fclose(to);
 404                         return (0);
 405                 }
 406                 if (done) {
 407                         (void)fprintf(to, "%s", buf);
 408                         if (ferror(to)) {
 409                                 snprintf(errbuf, errbufsz, "%s",
 410                                     strerror(errno));
 411                                 (void)fclose(from);
 412                                 (void)fclose(to);
 413                                 return (0);
 414                         }
 415                         continue;
 416                 }
 417                 if (!(p = strchr(buf, ':'))) {
 418                         snprintf(errbuf, errbufsz, "%s: corrupted entry", mpwd);
 419                         (void)fclose(from);
 420                         (void)fclose(to);
 421                         return (0);
 422                 }
 423                 *p = '\0';
 424                 if (strcmp(buf, pw->pw_name)) {
 425                         *p = ':';
 426                         (void)fprintf(to, "%s", buf);
 427                         if (ferror(to)) {
 428                                 snprintf(errbuf, errbufsz, "%s",
 429                                     strerror(errno));
 430                                 (void)fclose(from);
 431                                 (void)fclose(to);
 432                                 return (0);
 433                         }
 434                         continue;
 435                 }
 436                 *p = ':';
 437                 if (old_pw && (neq = pw_equal(buf, old_pw)) != NULL) {
 438                         if (strcmp(neq, "corrupt line") == 0)
 439                                 (void)snprintf(errbuf, errbufsz,
 440                                     "%s: entry %s corrupted", mpwd,
 441                                     pw->pw_name);
 442                         else
 443                                 (void)snprintf(errbuf, errbufsz,
 444                                     "%s: entry %s inconsistent %s",
 445                                     mpwd, pw->pw_name, neq);
 446                         (void)fclose(from);
 447                         (void)fclose(to);
 448                         return (0);
 449                 }
 450                 pw_print(to, pw);
 451                 done = 1;
 452                 if (ferror(to)) {
 453                         snprintf(errbuf, errbufsz, "%s", strerror(errno));
 454                         (void)fclose(from);
 455                         (void)fclose(to);
 456                         return (0);
 457                 }
 458         }
 459         /* Only append a new entry if real uid is root! */
 460         if (!done) {
 461                 if (getuid() == 0) {
 462                         pw_print(to, pw);
 463                         done = 1;
 464                 } else {
 465                         snprintf(errbuf, errbufsz,
 466                             "%s: changes not made, no such entry", mpwd);
 467                 }
 468         }
 469
 470         if (ferror(to)) {
 471                 snprintf(errbuf, errbufsz, "%s", strerror(errno));
 472                 (void)fclose(from);
 473                 (void)fclose(to);
 474                 return (0);
 475         }
 476         (void)fclose(from);
 477         (void)fclose(to);
 478
 479         return (done);
 480 }
 481
 482 void
 483 pw_error(const char *name, int error, int eval)
 484 {
 485
 486         if (error) {
 487                 if (name)
 488                         warn("%s", name);
 489                 else
 490                         warn(NULL);
 491         }
 492
 493         warnx("%s%s: unchanged", pw_prefix, _PATH_MASTERPASSWD);
 494         pw_abort();
 495         exit(eval);
 496 }
 497
 498 /* Removes head and/or tail spaces. */
 499 static void
 500 trim_whitespace(char *line)
 501 {
 502         char *p;
 503
 504         _DIAGASSERT(line != NULL);
 505
 506         /* Remove leading spaces */
 507         p = line;
 508         while (isspace((unsigned char) *p))
 509                 p++;
 510         memmove(line, p, strlen(p) + 1);
 511
 512         /* Remove trailing spaces */
 513         p = line + strlen(line) - 1;
 514         while (isspace((unsigned char) *p))
 515                 p--;
 516         *(p + 1) = '\0';
 517 }
 518
 519
 520 /* Get one line, remove spaces from front and tail */
 521 static int
 522 read_line(FILE *fp, char *line, int max)
 523 {
 524         char   *p;
 525
 526         _DIAGASSERT(fp != NULL);
 527         _DIAGASSERT(line != NULL);
 528
 529         /* Read one line of config */
 530         if (fgets(line, max, fp) == NULL)
 531                 return (0);
 532
 533         if ((p = strchr(line, '\n')) == NULL) {
 534                 warnx("line too long");
 535                 return (0);
 536         }
 537         *p = '\0';
 538
 539         /* Remove comments */
 540         if ((p = strchr(line, '#')) != NULL)
 541                 *p = '\0';
 542
 543         trim_whitespace(line);
 544         return (1);
 545 }
 546
 547 static const char *
 548 pw_default(const char *option)
 549 {
 550         static const char *options[][2] = {
 551                 { "localcipher",        "old" },
 552                 { "ypcipher",           "old" },
 553         };
 554         size_t i;
 555
 556         _DIAGASSERT(option != NULL);
 557         for (i = 0; i < sizeof(options) / sizeof(options[0]); i++)
 558                 if (strcmp(options[i][0], option) == 0)
 559                         return (options[i][1]);
 560
 561         return (NULL);
 562 }
 563
 564 /*
 565  * Retrieve password information from the /etc/passwd.conf file, at the
 566  * moment this is only for choosing the cipher to use.  It could easily be
 567  * used for other authentication methods as well.
 568  */
 569 void
 570 pw_getconf(char *data, size_t max, const char *key, const char *option)
 571 {
 572         FILE *fp;
 573         char line[LINE_MAX], *p, *p2;
 574         static char result[LINE_MAX];
 575         int got, found;
 576         const char *cp;
 577
 578         _DIAGASSERT(data != NULL);
 579         _DIAGASSERT(key != NULL);
 580         _DIAGASSERT(option != NULL);
 581
 582         got = 0;
 583         found = 0;
 584         result[0] = '\0';
 585
 586         if ((fp = fopen(_PATH_PASSWD_CONF, "r")) == NULL) {
 587                 if ((cp = pw_default(option)) != NULL)
 588                         strlcpy(data, cp, max);
 589                 else
 590                         data[0] = '\0';
 591                 return;
 592         }
 593
 594         while (!found && (got || read_line(fp, line, LINE_MAX))) {
 595                 got = 0;
 596
 597                 if (strncmp(key, line, strlen(key)) != 0 ||
 598                     line[strlen(key)] != ':')
 599                         continue;
 600
 601                 /* Now we found our specified key */
 602                 while (read_line(fp, line, LINE_MAX)) {
 603                         /* Leaving key field */
 604                         if (line[0] != '\0' && strchr(line + 1, ':') != NULL) {
 605                                 got = 1;
 606                                 break;
 607                         }
 608                         p2 = line;
 609                         if ((p = strsep(&p2, "=")) == NULL || p2 == NULL)
 610                                 continue;
 611                         trim_whitespace(p);
 612
 613                         if (!strncmp(p, option, strlen(option))) {
 614                                 trim_whitespace(p2);
 615                                 strcpy(result, p2);
 616                                 found = 1;
 617                                 break;
 618                         }
 619                 }
 620         }
 621         fclose(fp);
 622
 623         if (!found)
 624                 errno = ENOENT;
 625         if (!got)
 626                 errno = ENOTDIR;
 627
 628         /*
 629          * If we got no result and were looking for a default
 630          * value, try hard coded defaults.
 631          */
 632
 633         if (strlen(result) == 0 && strcmp(key, "default") == 0 &&
 634             (cp = pw_default(option)) != NULL)
 635                 strlcpy(data, cp, max);
 636         else
 637                 strlcpy(data, result, max);
 638 }
 639
 640 void
 641 pw_getpwconf(char *data, size_t max, const struct passwd *pwd,
 642     const char *option)
 643 {
 644         char grpkey[LINE_MAX];
 645         struct group grs, *grp;
 646         char grbuf[1024];
 647
 648         pw_getconf(data, max, pwd->pw_name, option);
 649
 650         /* Try to find an entry for the group */
 651         if (*data == '\0') {
 652                 (void)getgrgid_r(pwd->pw_gid, &grs, grbuf, sizeof(grbuf), &grp);
 653                 if (grp != NULL) {
 654                         (void)snprintf(grpkey, sizeof(grpkey), ":%s",
 655                             grp->gr_name);
 656                         pw_getconf(data, max, grpkey, option);
 657                 }
 658                 if (*data == '\0')
 659                         pw_getconf(data, max, "default", option);
 660         }
 661 }