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passwd.c revision 1.45 
      1 /*	$NetBSD: passwd.c,v 1.45 2006/12/20 16:47:13 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 1.45 2006/12/20 16:47:13 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 int		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 static int
    294 pw_equal(char *buf, struct passwd *pw)
    295 {
    296 	struct passwd buf_pw;
    297 	size_t len;
    298 
    299 	_DIAGASSERT(buf != NULL);
    300 	_DIAGASSERT(pw != NULL);
    301 
    302 	len = strlen (buf);
    303 	if (buf[len-1] == '\n')
    304 		buf[len-1] = '\0';
    305 	if (!pw_scan(buf, &buf_pw, NULL))
    306 		return 0;
    307 	return !strcmp(pw->pw_name, buf_pw.pw_name)
    308 		&& pw->pw_uid == buf_pw.pw_uid
    309 		&& pw->pw_gid == buf_pw.pw_gid
    310 		&& !strcmp(pw->pw_class, buf_pw.pw_class)
    311 		&& (long)pw->pw_change == (long)buf_pw.pw_change
    312 		&& (long)pw->pw_expire == (long)buf_pw.pw_expire
    313 		&& !strcmp(pw->pw_gecos, buf_pw.pw_gecos)
    314 		&& !strcmp(pw->pw_dir, buf_pw.pw_dir)
    315 		&& !strcmp(pw->pw_shell, buf_pw.pw_shell);
    316 }
    317 
    318 void
    319 pw_copy(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw)
    320 {
    321 	char errbuf[200];
    322 	int rv;
    323 
    324 	rv = pw_copyx(ffd, tfd, pw, old_pw, errbuf, sizeof(errbuf));
    325 	if (rv == 0) {
    326 		warnx("%s", errbuf);
    327 		pw_error(NULL, 0, 1);
    328 	}
    329 }
    330 
    331 int
    332 pw_copyx(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw,
    333     char *errbuf, size_t errbufsz)
    334 {
    335 	const char *filename;
    336 	char mpwd[MAXPATHLEN], mpwdl[MAXPATHLEN], *p, buf[8192];
    337 	FILE *from, *to;
    338 	int done;
    339 
    340 	_DIAGASSERT(pw != NULL);
    341 	_DIAGASSERT(errbuf != NULL);
    342 	/* old_pw may be NULL */
    343 
    344 	if ((filename = pw_filename(_PATH_MASTERPASSWD)) == NULL) {
    345 		snprintf(errbuf, errbufsz, "%s: %s", pw_prefix,
    346 		    strerror(errno));
    347 		return (0);
    348 	}
    349 	(void)strcpy(mpwd, filename);
    350 	if ((filename = pw_filename(_PATH_MASTERPASSWD_LOCK)) == NULL) {
    351 		snprintf(errbuf, errbufsz, "%s: %s", pw_prefix,
    352 		    strerror(errno));
    353 		return (0);
    354 	}
    355 	(void)strcpy(mpwdl, filename);
    356 
    357 	if (!(from = fdopen(ffd, "r"))) {
    358 		snprintf(errbuf, errbufsz, "%s: %s", mpwd, strerror(errno));
    359 		return (0);
    360 	}
    361 	if (!(to = fdopen(tfd, "w"))) {
    362 		snprintf(errbuf, errbufsz, "%s: %s", mpwdl, strerror(errno));
    363 		(void)fclose(from);
    364 		return (0);
    365 	}
    366 
    367 	for (done = 0; fgets(buf, (int)sizeof(buf), from);) {
    368 		if (!strchr(buf, '\n')) {
    369 			snprintf(errbuf, errbufsz, "%s: line too long", mpwd);
    370 			(void)fclose(from);
    371 			(void)fclose(to);
    372 			return (0);
    373 		}
    374 		if (done) {
    375 			(void)fprintf(to, "%s", buf);
    376 			if (ferror(to)) {
    377 				snprintf(errbuf, errbufsz, "%s",
    378 				    strerror(errno));
    379 				(void)fclose(from);
    380 				(void)fclose(to);
    381 				return (0);
    382 			}
    383 			continue;
    384 		}
    385 		if (!(p = strchr(buf, ':'))) {
    386 			snprintf(errbuf, errbufsz, "%s: corrupted entry", mpwd);
    387 			(void)fclose(from);
    388 			(void)fclose(to);
    389 			return (0);
    390 		}
    391 		*p = '\0';
    392 		if (strcmp(buf, pw->pw_name)) {
    393 			*p = ':';
    394 			(void)fprintf(to, "%s", buf);
    395 			if (ferror(to)) {
    396 				snprintf(errbuf, errbufsz, "%s",
    397 				    strerror(errno));
    398 				(void)fclose(from);
    399 				(void)fclose(to);
    400 				return (0);
    401 			}
    402 			continue;
    403 		}
    404 		*p = ':';
    405 		if (old_pw && !pw_equal(buf, old_pw)) {
    406 			snprintf(errbuf, errbufsz, "%s: entry inconsistent",
    407 			    mpwd);
    408 			(void)fclose(from);
    409 			(void)fclose(to);
    410 			return (0);
    411 		}
    412 		(void)fprintf(to, "%s:%s:%d:%d:%s:%ld:%ld:%s:%s:%s\n",
    413 		    pw->pw_name, pw->pw_passwd, pw->pw_uid, pw->pw_gid,
    414 		    pw->pw_class, (long)pw->pw_change, (long)pw->pw_expire,
    415 		    pw->pw_gecos, pw->pw_dir, pw->pw_shell);
    416 		done = 1;
    417 		if (ferror(to)) {
    418 			snprintf(errbuf, errbufsz, "%s", strerror(errno));
    419 			(void)fclose(from);
    420 			(void)fclose(to);
    421 			return (0);
    422 		}
    423 	}
    424 	/* Only append a new entry if real uid is root! */
    425 	if (!done) {
    426 		if (getuid() == 0) {
    427 			(void)fprintf(to, "%s:%s:%d:%d:%s:%ld:%ld:%s:%s:%s\n",
    428 			    pw->pw_name, pw->pw_passwd, pw->pw_uid, pw->pw_gid,
    429 			    pw->pw_class, (long)pw->pw_change,
    430 			    (long)pw->pw_expire, pw->pw_gecos, pw->pw_dir,
    431 			    pw->pw_shell);
    432 			done = 1;
    433 		} else {
    434 			snprintf(errbuf, errbufsz,
    435 			    "%s: changes not made, no such entry", mpwd);
    436 		}
    437 	}
    438 
    439 	if (ferror(to)) {
    440 		snprintf(errbuf, errbufsz, "%s", strerror(errno));
    441 		(void)fclose(from);
    442 		(void)fclose(to);
    443 		return (0);
    444 	}
    445 	(void)fclose(from);
    446 	(void)fclose(to);
    447 
    448 	return (done);
    449 }
    450 
    451 void
    452 pw_error(const char *name, int error, int eval)
    453 {
    454 
    455 	if (error) {
    456 		if (name)
    457 			warn("%s", name);
    458 		else
    459 			warn(NULL);
    460 	}
    461 
    462 	warnx("%s%s: unchanged", pw_prefix, _PATH_MASTERPASSWD);
    463 	pw_abort();
    464 	exit(eval);
    465 }
    466 
    467 /* Removes head and/or tail spaces. */
    468 static void
    469 trim_whitespace(char *line)
    470 {
    471 	char *p;
    472 
    473 	_DIAGASSERT(line != NULL);
    474 
    475 	/* Remove leading spaces */
    476 	p = line;
    477 	while (isspace((unsigned char) *p))
    478 		p++;
    479 	memmove(line, p, strlen(p) + 1);
    480 
    481 	/* Remove trailing spaces */
    482 	p = line + strlen(line) - 1;
    483 	while (isspace((unsigned char) *p))
    484 		p--;
    485 	*(p + 1) = '\0';
    486 }
    487 
    488 
    489 /* Get one line, remove spaces from front and tail */
    490 static int
    491 read_line(FILE *fp, char *line, int max)
    492 {
    493 	char   *p;
    494 
    495 	_DIAGASSERT(fp != NULL);
    496 	_DIAGASSERT(line != NULL);
    497 
    498 	/* Read one line of config */
    499 	if (fgets(line, max, fp) == NULL)
    500 		return (0);
    501 
    502 	if ((p = strchr(line, '\n')) == NULL) {
    503 		warnx("line too long");
    504 		return (0);
    505 	}
    506 	*p = '\0';
    507 
    508 	/* Remove comments */
    509 	if ((p = strchr(line, '#')) != NULL)
    510 		*p = '\0';
    511 
    512 	trim_whitespace(line);
    513 	return (1);
    514 }
    515 
    516 static const char *
    517 pw_default(const char *option)
    518 {
    519 	static const char *options[][2] = {
    520 		{ "localcipher",	"old" },
    521 		{ "ypcipher",		"old" },
    522 	};
    523 	int i;
    524 
    525 	_DIAGASSERT(option != NULL);
    526 	for (i = 0; i < sizeof(options) / sizeof(options[0]); i++)
    527 		if (strcmp(options[i][0], option) == 0)
    528 			return (options[i][1]);
    529 
    530 	return (NULL);
    531 }
    532 
    533 /*
    534  * Retrieve password information from the /etc/passwd.conf file, at the
    535  * moment this is only for choosing the cipher to use.  It could easily be
    536  * used for other authentication methods as well.
    537  */
    538 void
    539 pw_getconf(char *data, size_t max, const char *key, const char *option)
    540 {
    541 	FILE *fp;
    542 	char line[LINE_MAX], *p, *p2;
    543 	static char result[LINE_MAX];
    544 	int got, found;
    545 	const char *cp;
    546 
    547 	_DIAGASSERT(data != NULL);
    548 	_DIAGASSERT(key != NULL);
    549 	_DIAGASSERT(option != NULL);
    550 
    551 	got = 0;
    552 	found = 0;
    553 	result[0] = '\0';
    554 
    555 	if ((fp = fopen(_PATH_PASSWD_CONF, "r")) == NULL) {
    556 		if ((cp = pw_default(option)) != NULL)
    557 			strlcpy(data, cp, max);
    558 		else
    559 			data[0] = '\0';
    560 		return;
    561 	}
    562 
    563 	while (!found && (got || read_line(fp, line, LINE_MAX))) {
    564 		got = 0;
    565 
    566 		if (strncmp(key, line, strlen(key)) != 0 ||
    567 		    line[strlen(key)] != ':')
    568 			continue;
    569 
    570 		/* Now we found our specified key */
    571 		while (read_line(fp, line, LINE_MAX)) {
    572 			/* Leaving key field */
    573 			if (line[0] != '\0' && strchr(line + 1, ':') != NULL) {
    574 				got = 1;
    575 				break;
    576 			}
    577 			p2 = line;
    578 			if ((p = strsep(&p2, "=")) == NULL || p2 == NULL)
    579 				continue;
    580 			trim_whitespace(p);
    581 
    582 			if (!strncmp(p, option, strlen(option))) {
    583 				trim_whitespace(p2);
    584 				strcpy(result, p2);
    585 				found = 1;
    586 				break;
    587 			}
    588 		}
    589 	}
    590 	fclose(fp);
    591 
    592 	if (!found)
    593 		errno = ENOENT;
    594 	if (!got)
    595 		errno = ENOTDIR;
    596 
    597 	/*
    598 	 * If we got no result and were looking for a default
    599 	 * value, try hard coded defaults.
    600 	 */
    601 
    602 	if (strlen(result) == 0 && strcmp(key, "default") == 0 &&
    603 	    (cp = pw_default(option)) != NULL)
    604 		strlcpy(data, cp, max);
    605 	else
    606 		strlcpy(data, result, max);
    607 }
    608 
    609 void
    610 pw_getpwconf(char *data, size_t max, const struct passwd *pwd,
    611     const char *option)
    612 {
    613 	char grpkey[LINE_MAX];
    614 	struct group grs, *grp;
    615 	char grbuf[1024];
    616 
    617 	pw_getconf(data, max, pwd->pw_name, option);
    618 
    619 	/* Try to find an entry for the group */
    620 	if (*data == '\0') {
    621 		(void)getgrgid_r(pwd->pw_gid, &grs, grbuf, sizeof(grbuf), &grp);
    622 		if (grp != NULL) {
    623 			(void)snprintf(grpkey, sizeof(grpkey), ":%s",
    624 			    grp->gr_name);
    625 			pw_getconf(data, max, grpkey, option);
    626 		}
    627 		if (*data == '\0')
    628 		        pw_getconf(data, max, "default", option);
    629 	}
    630 }
    631