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passwd.c revision 1.39 
      1 /*	$NetBSD: passwd.c,v 1.39 2005/01/15 03:07:56 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 1.39 2005/01/15 03:07:56 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 *editor;
    230 	const char *argp[] = { "sh", "-c", NULL, NULL };
    231 
    232 #ifdef __GNUC__
    233 	(void) &editor;
    234 #endif
    235 
    236 	if (filename == NULL)
    237 		filename = _PATH_MASTERPASSWD_LOCK;
    238 
    239 	filename = pw_filename(filename);
    240 	if (filename == NULL)
    241 		return;
    242 
    243 	if ((editor = getenv("EDITOR")) == NULL)
    244 		editor = _PATH_VI;
    245 
    246 	p = malloc(strlen(editor) + 1 + strlen(filename) + 1);
    247 	if (p == NULL)
    248 		return;
    249 
    250 	sprintf(p, "%s %s", editor, filename);
    251 	argp[2] = p;
    252 
    253 	switch(editpid = vfork()) {
    254 	case -1:
    255 		free(p);
    256 		return;
    257 	case 0:
    258 		if (notsetuid) {
    259 			setgid(getgid());
    260 			setuid(getuid());
    261 		}
    262 		execvp(_PATH_BSHELL, (char *const *)__UNCONST(argp));
    263 		_exit(1);
    264 	}
    265 
    266 	free(p);
    267 
    268 	for (;;) {
    269 		editpid = waitpid(editpid, (int *)&pstat, WUNTRACED);
    270 		if (editpid == -1)
    271 			pw_error(editor, 1, 1);
    272 		else if (WIFSTOPPED(pstat))
    273 			raise(WSTOPSIG(pstat));
    274 		else if (WIFEXITED(pstat) && WEXITSTATUS(pstat) == 0)
    275 			break;
    276 		else
    277 			pw_error(editor, 1, 1);
    278 	}
    279 	editpid = -1;
    280 }
    281 
    282 void
    283 pw_prompt(void)
    284 {
    285 	int c;
    286 
    287 	(void)printf("re-edit the password file? [y]: ");
    288 	(void)fflush(stdout);
    289 	c = getchar();
    290 	if (c != EOF && c != '\n')
    291 		while (getchar() != '\n');
    292 	if (c == 'n')
    293 		pw_error(NULL, 0, 0);
    294 }
    295 
    296 /* for use in pw_copy(). Compare a pw entry to a pw struct. */
    297 static int
    298 pw_equal(char *buf, struct passwd *pw)
    299 {
    300 	struct passwd buf_pw;
    301 	int len;
    302 
    303 	_DIAGASSERT(buf != NULL);
    304 	_DIAGASSERT(pw != NULL);
    305 
    306 	len = strlen (buf);
    307 	if (buf[len-1] == '\n')
    308 		buf[len-1] = '\0';
    309 	if (!pw_scan(buf, &buf_pw, NULL))
    310 		return 0;
    311 	return !strcmp(pw->pw_name, buf_pw.pw_name)
    312 		&& pw->pw_uid == buf_pw.pw_uid
    313 		&& pw->pw_gid == buf_pw.pw_gid
    314 		&& !strcmp(pw->pw_class, buf_pw.pw_class)
    315 		&& (long)pw->pw_change == (long)buf_pw.pw_change
    316 		&& (long)pw->pw_expire == (long)buf_pw.pw_expire
    317 		&& !strcmp(pw->pw_gecos, buf_pw.pw_gecos)
    318 		&& !strcmp(pw->pw_dir, buf_pw.pw_dir)
    319 		&& !strcmp(pw->pw_shell, buf_pw.pw_shell);
    320 }
    321 
    322 void
    323 pw_copy(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw)
    324 {
    325 	char errbuf[200];
    326 	int rv;
    327 
    328 	rv = pw_copyx(ffd, tfd, pw, old_pw, errbuf, sizeof(errbuf));
    329 	if (rv == 0) {
    330 		warnx("%s", errbuf);
    331 		pw_error(NULL, 0, 1);
    332 	}
    333 }
    334 
    335 int
    336 pw_copyx(int ffd, int tfd, struct passwd *pw, struct passwd *old_pw,
    337     char *errbuf, size_t errbufsz)
    338 {
    339 	const char *filename;
    340 	char mpwd[MAXPATHLEN], mpwdl[MAXPATHLEN], *p, buf[8192];
    341 	FILE *from, *to;
    342 	int done;
    343 
    344 	_DIAGASSERT(pw != NULL);
    345 	_DIAGASSERT(errbuf != NULL);
    346 	/* old_pw may be NULL */
    347 
    348 	if ((filename = pw_filename(_PATH_MASTERPASSWD)) == NULL) {
    349 		snprintf(errbuf, errbufsz, "%s: %s", pw_prefix,
    350 		    strerror(errno));
    351 		return (0);
    352 	}
    353 	(void)strcpy(mpwd, filename);
    354 	if ((filename = pw_filename(_PATH_MASTERPASSWD_LOCK)) == NULL) {
    355 		snprintf(errbuf, errbufsz, "%s: %s", pw_prefix,
    356 		    strerror(errno));
    357 		return (0);
    358 	}
    359 	(void)strcpy(mpwdl, filename);
    360 
    361 	if (!(from = fdopen(ffd, "r"))) {
    362 		snprintf(errbuf, errbufsz, "%s: %s", mpwd, strerror(errno));
    363 		return (0);
    364 	}
    365 	if (!(to = fdopen(tfd, "w"))) {
    366 		snprintf(errbuf, errbufsz, "%s: %s", mpwdl, strerror(errno));
    367 		return (0);
    368 	}
    369 
    370 	for (done = 0; fgets(buf, sizeof(buf), from);) {
    371 		if (!strchr(buf, '\n')) {
    372 			snprintf(errbuf, errbufsz, "%s: line too long", mpwd);
    373 			return (0);
    374 		}
    375 		if (done) {
    376 			(void)fprintf(to, "%s", buf);
    377 			if (ferror(to)) {
    378 				snprintf(errbuf, errbufsz, "%s",
    379 				    strerror(errno));
    380 				return (0);
    381 			}
    382 			continue;
    383 		}
    384 		if (!(p = strchr(buf, ':'))) {
    385 			snprintf(errbuf, errbufsz, "%s: corrupted entry", mpwd);
    386 			return (0);
    387 		}
    388 		*p = '\0';
    389 		if (strcmp(buf, pw->pw_name)) {
    390 			*p = ':';
    391 			(void)fprintf(to, "%s", buf);
    392 			if (ferror(to)) {
    393 				snprintf(errbuf, errbufsz, "%s",
    394 				    strerror(errno));
    395 				return (0);
    396 			}
    397 			continue;
    398 		}
    399 		*p = ':';
    400 		if (old_pw && !pw_equal(buf, old_pw)) {
    401 			snprintf(errbuf, errbufsz, "%s: entry inconsistent",
    402 			    mpwd);
    403 			return (0);
    404 		}
    405 		(void)fprintf(to, "%s:%s:%d:%d:%s:%ld:%ld:%s:%s:%s\n",
    406 		    pw->pw_name, pw->pw_passwd, pw->pw_uid, pw->pw_gid,
    407 		    pw->pw_class, (long)pw->pw_change, (long)pw->pw_expire,
    408 		    pw->pw_gecos, pw->pw_dir, pw->pw_shell);
    409 		done = 1;
    410 		if (ferror(to)) {
    411 			snprintf(errbuf, errbufsz, "%s", strerror(errno));
    412 			return (0);
    413 		}
    414 	}
    415 	/* Only append a new entry if real uid is root! */
    416 	if (!done) {
    417 		if (getuid() == 0) {
    418 			(void)fprintf(to, "%s:%s:%d:%d:%s:%ld:%ld:%s:%s:%s\n",
    419 			    pw->pw_name, pw->pw_passwd, pw->pw_uid, pw->pw_gid,
    420 			    pw->pw_class, (long)pw->pw_change,
    421 			    (long)pw->pw_expire, pw->pw_gecos, pw->pw_dir,
    422 			    pw->pw_shell);
    423 			done = 1;
    424 		} else {
    425 			snprintf(errbuf, errbufsz,
    426 			    "%s: changes not made, no such entry", mpwd);
    427 		}
    428 	}
    429 
    430 	if (ferror(to)) {
    431 		snprintf(errbuf, errbufsz, "%s", strerror(errno));
    432 		return (0);
    433 	}
    434 	(void)fclose(to);
    435 
    436 	return (done);
    437 }
    438 
    439 void
    440 pw_error(const char *name, int error, int eval)
    441 {
    442 
    443 	if (error) {
    444 		if (name)
    445 			warn("%s", name);
    446 		else
    447 			warn(NULL);
    448 	}
    449 
    450 	warnx("%s%s: unchanged", pw_prefix, _PATH_MASTERPASSWD);
    451 	pw_abort();
    452 	exit(eval);
    453 }
    454 
    455 /* Removes head and/or tail spaces. */
    456 static void
    457 trim_whitespace(char *line)
    458 {
    459 	char *p;
    460 
    461 	_DIAGASSERT(line != NULL);
    462 
    463 	/* Remove leading spaces */
    464 	p = line;
    465 	while (isspace((unsigned char) *p))
    466 		p++;
    467 	memmove(line, p, strlen(p) + 1);
    468 
    469 	/* Remove trailing spaces */
    470 	p = line + strlen(line) - 1;
    471 	while (isspace((unsigned char) *p))
    472 		p--;
    473 	*(p + 1) = '\0';
    474 }
    475 
    476 
    477 /* Get one line, remove spaces from front and tail */
    478 static int
    479 read_line(FILE *fp, char *line, int max)
    480 {
    481 	char   *p;
    482 
    483 	_DIAGASSERT(fp != NULL);
    484 	_DIAGASSERT(line != NULL);
    485 
    486 	/* Read one line of config */
    487 	if (fgets(line, max, fp) == NULL)
    488 		return (0);
    489 
    490 	if ((p = strchr(line, '\n')) == NULL) {
    491 		warnx("line too long");
    492 		return (0);
    493 	}
    494 	*p = '\0';
    495 
    496 	/* Remove comments */
    497 	if ((p = strchr(line, '#')) != NULL)
    498 		*p = '\0';
    499 
    500 	trim_whitespace(line);
    501 	return (1);
    502 }
    503 
    504 static const char *
    505 pw_default(const char *option)
    506 {
    507 	static const char *options[][2] = {
    508 		{ "localcipher",	"old" },
    509 		{ "ypcipher",		"old" },
    510 	};
    511 	int i;
    512 
    513 	_DIAGASSERT(option != NULL);
    514 	for (i = 0; i < sizeof(options) / sizeof(options[0]); i++)
    515 		if (strcmp(options[i][0], option) == 0)
    516 			return (options[i][1]);
    517 
    518 	return (NULL);
    519 }
    520 
    521 /*
    522  * Retrieve password information from the /etc/passwd.conf file, at the
    523  * moment this is only for choosing the cipher to use.  It could easily be
    524  * used for other authentication methods as well.
    525  */
    526 void
    527 pw_getconf(char *data, size_t max, const char *key, const char *option)
    528 {
    529 	FILE *fp;
    530 	char line[LINE_MAX], *p, *p2;
    531 	static char result[LINE_MAX];
    532 	int got, found;
    533 	const char *cp;
    534 
    535 	_DIAGASSERT(data != NULL);
    536 	_DIAGASSERT(key != NULL);
    537 	_DIAGASSERT(option != NULL);
    538 
    539 	got = 0;
    540 	found = 0;
    541 	result[0] = '\0';
    542 
    543 	if ((fp = fopen(_PATH_PASSWD_CONF, "r")) == NULL) {
    544 		if ((cp = pw_default(option)) != NULL)
    545 			strlcpy(data, cp, max);
    546 		else
    547 			data[0] = '\0';
    548 		return;
    549 	}
    550 
    551 	while (!found && (got || read_line(fp, line, LINE_MAX))) {
    552 		got = 0;
    553 
    554 		if (strncmp(key, line, strlen(key)) != 0 ||
    555 		    line[strlen(key)] != ':')
    556 			continue;
    557 
    558 		/* Now we found our specified key */
    559 		while (read_line(fp, line, LINE_MAX)) {
    560 			/* Leaving key field */
    561 			if (line[0] != '\0' && strchr(line + 1, ':') != NULL) {
    562 				got = 1;
    563 				break;
    564 			}
    565 			p2 = line;
    566 			if ((p = strsep(&p2, "=")) == NULL || p2 == NULL)
    567 				continue;
    568 			trim_whitespace(p);
    569 
    570 			if (!strncmp(p, option, strlen(option))) {
    571 				trim_whitespace(p2);
    572 				strcpy(result, p2);
    573 				found = 1;
    574 				break;
    575 			}
    576 		}
    577 	}
    578 	fclose(fp);
    579 
    580 	/*
    581 	 * If we got no result and were looking for a default
    582 	 * value, try hard coded defaults.
    583 	 */
    584 
    585 	if (strlen(result) == 0 && strcmp(key, "default") == 0 &&
    586 	    (cp = pw_default(option)) != NULL)
    587 		strlcpy(data, cp, max);
    588 	else
    589 		strlcpy(data, result, max);
    590 }
    591 
    592 void
    593 pw_getpwconf(char *data, size_t max, const struct passwd *pwd,
    594     const char *option)
    595 {
    596 	char grpkey[LINE_MAX];
    597 	struct group *grp;
    598 
    599 	pw_getconf(data, max, pwd->pw_name, option);
    600 
    601 	/* Try to find an entry for the group */
    602 	if (*data == '\0') {
    603 		if ((grp = getgrgid(pwd->pw_gid)) != NULL) {
    604 			snprintf(grpkey, sizeof(grpkey), ":%s", grp->gr_name);
    605 			pw_getconf(data, max, grpkey, option);
    606 		}
    607 		if (*data == '\0')
    608 		        pw_getconf(data, max, "default", option);
    609 	}
    610 }
    611