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passwd.c revision 1.50 
      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 	struct rlimit rlim;
    213 
    214 	/* Unlimited resource limits. */
    215 	rlim.rlim_cur = rlim.rlim_max = RLIM_INFINITY;
    216 	(void)setrlimit(RLIMIT_CPU, &rlim);
    217 	(void)setrlimit(RLIMIT_FSIZE, &rlim);
    218 	(void)setrlimit(RLIMIT_STACK, &rlim);
    219 	(void)setrlimit(RLIMIT_DATA, &rlim);
    220 	(void)setrlimit(RLIMIT_RSS, &rlim);
    221 
    222 	/* Don't drop core (not really necessary, but GP's). */
    223 	rlim.rlim_cur = rlim.rlim_max = 0;
    224 	(void)setrlimit(RLIMIT_CORE, &rlim);
    225 
    226 	/* Turn off signals. */
    227 	(void)signal(SIGALRM, SIG_IGN);
    228 	(void)signal(SIGHUP, SIG_IGN);
    229 	(void)signal(SIGINT, SIG_IGN);
    230 	(void)signal(SIGPIPE, SIG_IGN);
    231 	(void)signal(SIGQUIT, SIG_IGN);
    232 	(void)signal(SIGTERM, SIG_IGN);
    233 	(void)signal(SIGCONT, pw_cont);
    234 }
    235 
    236 void
    237 pw_edit(int notsetuid, const char *filename)
    238 {
    239 	int pstat;
    240 	char *p;
    241 	const char * volatile editor;
    242 	const char *argp[] = { "sh", "-c", NULL, NULL };
    243 
    244 	if (filename == NULL)
    245 		filename = _PATH_MASTERPASSWD_LOCK;
    246 
    247 	filename = pw_filename(filename);
    248 	if (filename == NULL)
    249 		return;
    250 
    251 	if ((editor = getenv("EDITOR")) == NULL)
    252 		editor = _PATH_VI;
    253 
    254 	p = malloc(strlen(editor) + 1 + strlen(filename) + 1);
    255 	if (p == NULL)
    256 		return;
    257 
    258 	sprintf(p, "%s %s", editor, filename);
    259 	argp[2] = p;
    260 
    261 	switch(editpid = vfork()) {
    262 	case -1:
    263 		free(p);
    264 		return;
    265 	case 0:
    266 		if (notsetuid) {
    267 			setgid(getgid());
    268 			setuid(getuid());
    269 		}
    270 		execvp(_PATH_BSHELL, (char *const *)__UNCONST(argp));
    271 		_exit(1);
    272 	}
    273 
    274 	free(p);
    275 
    276 	for (;;) {
    277 		editpid = waitpid(editpid, (int *)&pstat, WUNTRACED);
    278 		if (editpid == -1)
    279 			pw_error(editor, 1, 1);
    280 		else if (WIFSTOPPED(pstat))
    281 			raise(WSTOPSIG(pstat));
    282 		else if (WIFEXITED(pstat) && WEXITSTATUS(pstat) == 0)
    283 			break;
    284 		else
    285 			pw_error(editor, 1, 1);
    286 	}
    287 	editpid = -1;
    288 }
    289 
    290 void
    291 pw_prompt(void)
    292 {
    293 	int c;
    294 
    295 	(void)printf("re-edit the password file? [y]: ");
    296 	(void)fflush(stdout);
    297 	c = getchar();
    298 	if (c != EOF && c != '\n')
    299 		while (getchar() != '\n');
    300 	if (c == 'n')
    301 		pw_error(NULL, 0, 0);
    302 }
    303 
    304 /* for use in pw_copy(). Compare a pw entry to a pw struct. */
    305 /* returns a character string labelling the miscompared field or 0 */
    306 static const char *
    307 pw_equal(char *buf, struct passwd *pw)
    308 {
    309 	struct passwd buf_pw;
    310 	size_t len;
    311 
    312 	_DIAGASSERT(buf != NULL);
    313 	_DIAGASSERT(pw != NULL);
    314 
    315 	len = strlen (buf);
    316 	if (buf[len-1] == '\n')
    317 		buf[len-1] = '\0';
    318 	if (!pw_scan(buf, &buf_pw, NULL))
    319 		return "corrupt line";
    320 	if (strcmp(pw->pw_name, buf_pw.pw_name) != 0)
    321 		return "name";
    322 	if (pw->pw_uid != buf_pw.pw_uid)
    323 		return "uid";
    324 	if (pw->pw_gid != buf_pw.pw_gid)
    325 		return "gid";
    326 	if (strcmp( pw->pw_class, buf_pw.pw_class) != 0)
    327 		return "class";
    328 	if (pw->pw_change != buf_pw.pw_change)
    329 		return "change";
    330 	if (pw->pw_expire != buf_pw.pw_expire)
    331 		return "expire";
    332 	if (strcmp( pw->pw_gecos, buf_pw.pw_gecos) != 0)
    333 		return "gecos";
    334 	if (strcmp( pw->pw_dir, buf_pw.pw_dir) != 0)
    335 		return "dir";
    336 	if (strcmp( pw->pw_shell, buf_pw.pw_shell) != 0)
    337 		return "shell";
    338 	return (char *)0;
    339 }
    340 
    341 void
    342 pw_copy(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw)
    343 {
    344 	char errbuf[200];
    345 	int rv;
    346 
    347 	rv = pw_copyx(ffd, tfd, pw, old_pw, errbuf, sizeof(errbuf));
    348 	if (rv == 0) {
    349 		warnx("%s", errbuf);
    350 		pw_error(NULL, 0, 1);
    351 	}
    352 }
    353 
    354 static void
    355 pw_print(FILE *to, const struct passwd *pw)
    356 {
    357 	(void)fprintf(to, "%s:%s:%d:%d:%s:%lld:%lld:%s:%s:%s\n",
    358 	    pw->pw_name, pw->pw_passwd, pw->pw_uid, pw->pw_gid,
    359 	    pw->pw_class, (long long)pw->pw_change,
    360 	    (long long)pw->pw_expire,
    361 	    pw->pw_gecos, pw->pw_dir, pw->pw_shell);
    362 }
    363 
    364 int
    365 pw_copyx(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw,
    366     char *errbuf, size_t errbufsz)
    367 {
    368 	const char *filename;
    369 	char mpwd[MAXPATHLEN], mpwdl[MAXPATHLEN], *p, buf[8192];
    370 	FILE *from, *to;
    371 	int done;
    372 
    373 	_DIAGASSERT(pw != NULL);
    374 	_DIAGASSERT(errbuf != NULL);
    375 	/* old_pw may be NULL */
    376 
    377 	if ((filename = pw_filename(_PATH_MASTERPASSWD)) == NULL) {
    378 		snprintf(errbuf, errbufsz, "%s: %s", pw_prefix,
    379 		    strerror(errno));
    380 		return (0);
    381 	}
    382 	(void)strcpy(mpwd, filename);
    383 	if ((filename = pw_filename(_PATH_MASTERPASSWD_LOCK)) == NULL) {
    384 		snprintf(errbuf, errbufsz, "%s: %s", pw_prefix,
    385 		    strerror(errno));
    386 		return (0);
    387 	}
    388 	(void)strcpy(mpwdl, filename);
    389 
    390 	if (!(from = fdopen(ffd, "r"))) {
    391 		snprintf(errbuf, errbufsz, "%s: %s", mpwd, strerror(errno));
    392 		return (0);
    393 	}
    394 	if (!(to = fdopen(tfd, "w"))) {
    395 		snprintf(errbuf, errbufsz, "%s: %s", mpwdl, strerror(errno));
    396 		(void)fclose(from);
    397 		return (0);
    398 	}
    399 
    400 	for (done = 0; fgets(buf, (int)sizeof(buf), from);) {
    401 		const char *neq;
    402 		if (!strchr(buf, '\n')) {
    403 			snprintf(errbuf, errbufsz, "%s: line too long", mpwd);
    404 			(void)fclose(from);
    405 			(void)fclose(to);
    406 			return (0);
    407 		}
    408 		if (done) {
    409 			(void)fprintf(to, "%s", buf);
    410 			if (ferror(to)) {
    411 				snprintf(errbuf, errbufsz, "%s",
    412 				    strerror(errno));
    413 				(void)fclose(from);
    414 				(void)fclose(to);
    415 				return (0);
    416 			}
    417 			continue;
    418 		}
    419 		if (!(p = strchr(buf, ':'))) {
    420 			snprintf(errbuf, errbufsz, "%s: corrupted entry", mpwd);
    421 			(void)fclose(from);
    422 			(void)fclose(to);
    423 			return (0);
    424 		}
    425 		*p = '\0';
    426 		if (strcmp(buf, pw->pw_name)) {
    427 			*p = ':';
    428 			(void)fprintf(to, "%s", buf);
    429 			if (ferror(to)) {
    430 				snprintf(errbuf, errbufsz, "%s",
    431 				    strerror(errno));
    432 				(void)fclose(from);
    433 				(void)fclose(to);
    434 				return (0);
    435 			}
    436 			continue;
    437 		}
    438 		*p = ':';
    439 		if (old_pw && (neq = pw_equal(buf, old_pw)) != NULL) {
    440 			if (strcmp(neq, "corrupt line") == 0)
    441 				(void)snprintf(errbuf, errbufsz,
    442 				    "%s: entry %s corrupted", mpwd,
    443 				    pw->pw_name);
    444 			else
    445 				(void)snprintf(errbuf, errbufsz,
    446 				    "%s: entry %s inconsistent %s",
    447 				    mpwd, pw->pw_name, neq);
    448 			(void)fclose(from);
    449 			(void)fclose(to);
    450 			return (0);
    451 		}
    452 		pw_print(to, pw);
    453 		done = 1;
    454 		if (ferror(to)) {
    455 			snprintf(errbuf, errbufsz, "%s", strerror(errno));
    456 			(void)fclose(from);
    457 			(void)fclose(to);
    458 			return (0);
    459 		}
    460 	}
    461 	/* Only append a new entry if real uid is root! */
    462 	if (!done) {
    463 		if (getuid() == 0) {
    464 			pw_print(to, pw);
    465 			done = 1;
    466 		} else {
    467 			snprintf(errbuf, errbufsz,
    468 			    "%s: changes not made, no such entry", mpwd);
    469 		}
    470 	}
    471 
    472 	if (ferror(to)) {
    473 		snprintf(errbuf, errbufsz, "%s", strerror(errno));
    474 		(void)fclose(from);
    475 		(void)fclose(to);
    476 		return (0);
    477 	}
    478 	(void)fclose(from);
    479 	(void)fclose(to);
    480 
    481 	return (done);
    482 }
    483 
    484 void
    485 pw_error(const char *name, int error, int eval)
    486 {
    487 
    488 	if (error) {
    489 		if (name)
    490 			warn("%s", name);
    491 		else
    492 			warn(NULL);
    493 	}
    494 
    495 	warnx("%s%s: unchanged", pw_prefix, _PATH_MASTERPASSWD);
    496 	pw_abort();
    497 	exit(eval);
    498 }
    499 
    500 /* Removes head and/or tail spaces. */
    501 static void
    502 trim_whitespace(char *line)
    503 {
    504 	char *p;
    505 
    506 	_DIAGASSERT(line != NULL);
    507 
    508 	/* Remove leading spaces */
    509 	p = line;
    510 	while (isspace((unsigned char) *p))
    511 		p++;
    512 	memmove(line, p, strlen(p) + 1);
    513 
    514 	/* Remove trailing spaces */
    515 	p = line + strlen(line) - 1;
    516 	while (isspace((unsigned char) *p))
    517 		p--;
    518 	*(p + 1) = '\0';
    519 }
    520 
    521 
    522 /* Get one line, remove spaces from front and tail */
    523 static int
    524 read_line(FILE *fp, char *line, int max)
    525 {
    526 	char   *p;
    527 
    528 	_DIAGASSERT(fp != NULL);
    529 	_DIAGASSERT(line != NULL);
    530 
    531 	/* Read one line of config */
    532 	if (fgets(line, max, fp) == NULL)
    533 		return (0);
    534 
    535 	if ((p = strchr(line, '\n')) == NULL) {
    536 		warnx("line too long");
    537 		return (0);
    538 	}
    539 	*p = '\0';
    540 
    541 	/* Remove comments */
    542 	if ((p = strchr(line, '#')) != NULL)
    543 		*p = '\0';
    544 
    545 	trim_whitespace(line);
    546 	return (1);
    547 }
    548 
    549 static const char *
    550 pw_default(const char *option)
    551 {
    552 	static const char *options[][2] = {
    553 		{ "localcipher",	"old" },
    554 		{ "ypcipher",		"old" },
    555 	};
    556 	size_t i;
    557 
    558 	_DIAGASSERT(option != NULL);
    559 	for (i = 0; i < sizeof(options) / sizeof(options[0]); i++)
    560 		if (strcmp(options[i][0], option) == 0)
    561 			return (options[i][1]);
    562 
    563 	return (NULL);
    564 }
    565 
    566 /*
    567  * Retrieve password information from the /etc/passwd.conf file, at the
    568  * moment this is only for choosing the cipher to use.  It could easily be
    569  * used for other authentication methods as well.
    570  */
    571 void
    572 pw_getconf(char *data, size_t max, const char *key, const char *option)
    573 {
    574 	FILE *fp;
    575 	char line[LINE_MAX], *p, *p2;
    576 	static char result[LINE_MAX];
    577 	int got, found;
    578 	const char *cp;
    579 
    580 	_DIAGASSERT(data != NULL);
    581 	_DIAGASSERT(key != NULL);
    582 	_DIAGASSERT(option != NULL);
    583 
    584 	got = 0;
    585 	found = 0;
    586 	result[0] = '\0';
    587 
    588 	if ((fp = fopen(_PATH_PASSWD_CONF, "r")) == NULL) {
    589 		if ((cp = pw_default(option)) != NULL)
    590 			strlcpy(data, cp, max);
    591 		else
    592 			data[0] = '\0';
    593 		return;
    594 	}
    595 
    596 	while (!found && (got || read_line(fp, line, LINE_MAX))) {
    597 		got = 0;
    598 
    599 		if (strncmp(key, line, strlen(key)) != 0 ||
    600 		    line[strlen(key)] != ':')
    601 			continue;
    602 
    603 		/* Now we found our specified key */
    604 		while (read_line(fp, line, LINE_MAX)) {
    605 			/* Leaving key field */
    606 			if (line[0] != '\0' && strchr(line + 1, ':') != NULL) {
    607 				got = 1;
    608 				break;
    609 			}
    610 			p2 = line;
    611 			if ((p = strsep(&p2, "=")) == NULL || p2 == NULL)
    612 				continue;
    613 			trim_whitespace(p);
    614 
    615 			if (!strncmp(p, option, strlen(option))) {
    616 				trim_whitespace(p2);
    617 				strcpy(result, p2);
    618 				found = 1;
    619 				break;
    620 			}
    621 		}
    622 	}
    623 	fclose(fp);
    624 
    625 	if (!found)
    626 		errno = ENOENT;
    627 	if (!got)
    628 		errno = ENOTDIR;
    629 
    630 	/*
    631 	 * If we got no result and were looking for a default
    632 	 * value, try hard coded defaults.
    633 	 */
    634 
    635 	if (strlen(result) == 0 && strcmp(key, "default") == 0 &&
    636 	    (cp = pw_default(option)) != NULL)
    637 		strlcpy(data, cp, max);
    638 	else
    639 		strlcpy(data, result, max);
    640 }
    641 
    642 void
    643 pw_getpwconf(char *data, size_t max, const struct passwd *pwd,
    644     const char *option)
    645 {
    646 	char grpkey[LINE_MAX];
    647 	struct group grs, *grp;
    648 	char grbuf[1024];
    649 
    650 	pw_getconf(data, max, pwd->pw_name, option);
    651 
    652 	/* Try to find an entry for the group */
    653 	if (*data == '\0') {
    654 		(void)getgrgid_r(pwd->pw_gid, &grs, grbuf, sizeof(grbuf), &grp);
    655 		if (grp != NULL) {
    656 			(void)snprintf(grpkey, sizeof(grpkey), ":%s",
    657 			    grp->gr_name);
    658 			pw_getconf(data, max, grpkey, option);
    659 		}
    660 		if (*data == '\0')
    661 		        pw_getconf(data, max, "default", option);
    662 	}
    663 }
    664