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passwd.c revision 1.15
      1 /*	$NetBSD: passwd.c,v 1.15 1998/12/09 14:35:03 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. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #if defined(LIBC_SCCS) && !defined(lint)
     38 __RCSID("$NetBSD: passwd.c,v 1.15 1998/12/09 14:35:03 christos Exp $");
     39 #endif /* LIBC_SCCS and not lint */
     40 
     41 #include <sys/types.h>
     42 #include <sys/stat.h>
     43 #include <sys/time.h>
     44 #include <sys/resource.h>
     45 #include <sys/wait.h>
     46 
     47 #include <ctype.h>
     48 #include <err.h>
     49 #include <errno.h>
     50 #include <fcntl.h>
     51 #include <limits.h>
     52 #include <paths.h>
     53 #include <pwd.h>
     54 #include <signal.h>
     55 #include <stdio.h>
     56 #include <stdlib.h>
     57 #include <string.h>
     58 #include <unistd.h>
     59 #include <util.h>
     60 
     61 static void	pw_cont __P((int sig));
     62 static int	pw_equal __P((char *buf, struct passwd *old_pw));
     63 
     64 int
     65 pw_lock(retries)
     66 	int retries;
     67 {
     68 	int i, fd;
     69 	mode_t old_mode;
     70 	int oerrno;
     71 
     72 	/* Acquire the lock file. */
     73 	old_mode = umask(0);
     74 	fd = open(_PATH_MASTERPASSWD_LOCK, O_WRONLY|O_CREAT|O_EXCL, 0600);
     75 	for (i = 0; i < retries && fd < 0 && errno == EEXIST; i++) {
     76 		sleep(1);
     77 		fd = open(_PATH_MASTERPASSWD_LOCK, O_WRONLY|O_CREAT|O_EXCL,
     78 			  0600);
     79 	}
     80 	oerrno = errno;
     81 	(void)umask(old_mode);
     82 	errno = oerrno;
     83 	return(fd);
     84 }
     85 
     86 int
     87 pw_mkdb()
     88 {
     89 	int pstat;
     90 	pid_t pid;
     91 
     92 	pid = vfork();
     93 	if (pid == 0) {
     94 		execl(_PATH_PWD_MKDB, "pwd_mkdb", "-p",
     95 		      _PATH_MASTERPASSWD_LOCK, NULL);
     96 		_exit(1);
     97 	}
     98 	pid = waitpid(pid, &pstat, 0);
     99 	if (pid == -1 || !WIFEXITED(pstat) || WEXITSTATUS(pstat) != 0)
    100 		return(-1);
    101 	return(0);
    102 }
    103 
    104 int
    105 pw_abort()
    106 {
    107 	return(unlink(_PATH_MASTERPASSWD_LOCK));
    108 }
    109 
    110 /* Everything below this point is intended for the convenience of programs
    111  * which allow a user to interactively edit the passwd file.  Errors in the
    112  * routines below will cause the process to abort. */
    113 
    114 static pid_t editpid = -1;
    115 
    116 static void
    117 pw_cont(sig)
    118 	int sig;
    119 {
    120 
    121 	if (editpid != -1)
    122 		kill(editpid, sig);
    123 }
    124 
    125 void
    126 pw_init()
    127 {
    128 	struct rlimit rlim;
    129 
    130 	/* Unlimited resource limits. */
    131 	rlim.rlim_cur = rlim.rlim_max = RLIM_INFINITY;
    132 	(void)setrlimit(RLIMIT_CPU, &rlim);
    133 	(void)setrlimit(RLIMIT_FSIZE, &rlim);
    134 	(void)setrlimit(RLIMIT_STACK, &rlim);
    135 	(void)setrlimit(RLIMIT_DATA, &rlim);
    136 	(void)setrlimit(RLIMIT_RSS, &rlim);
    137 
    138 	/* Don't drop core (not really necessary, but GP's). */
    139 	rlim.rlim_cur = rlim.rlim_max = 0;
    140 	(void)setrlimit(RLIMIT_CORE, &rlim);
    141 
    142 	/* Turn off signals. */
    143 	(void)signal(SIGALRM, SIG_IGN);
    144 	(void)signal(SIGHUP, SIG_IGN);
    145 	(void)signal(SIGINT, SIG_IGN);
    146 	(void)signal(SIGPIPE, SIG_IGN);
    147 	(void)signal(SIGQUIT, SIG_IGN);
    148 	(void)signal(SIGTERM, SIG_IGN);
    149 	(void)signal(SIGCONT, pw_cont);
    150 }
    151 
    152 void
    153 pw_edit(notsetuid, filename)
    154 	int notsetuid;
    155 	const char *filename;
    156 {
    157 	int i, xargc, pstat;
    158 	char *p, *editor;
    159 	char **xargv;
    160 #ifdef __GNUC__
    161 	(void) &editor;
    162 #endif
    163 
    164 	if (filename == NULL)
    165 		filename = _PATH_MASTERPASSWD_LOCK;
    166 	if ((editor = getenv("EDITOR")) == NULL)
    167 		editor = strdup(_PATH_VI);
    168 	else
    169 		editor = strdup(editor);
    170 	if ((p = strrchr(editor, '/')) != NULL)
    171 		++p;
    172 	else
    173 		p = editor;
    174 
    175 	/* Scan editor string, count spaces, allocate arg vector. */
    176 	for (i = 0, xargc = 0; p[i] != '\0'; i++) {
    177 		if (isspace(p[i])) {
    178 			while (isspace(p[i++]))
    179 				/* skip white space */ ;
    180 			if (p[i] == '\0')
    181 				break;
    182 			xargc++;
    183 		}
    184 	}
    185 
    186 	/* argv[0] + <xargc args> + filename + NULL */
    187 	xargv = (char **)malloc(sizeof(char *) * (xargc + 3));
    188 	if (xargv == NULL)
    189 		pw_error("malloc failed", 1, 1);
    190 
    191 	i = 0;
    192 	xargv[i++] = p;
    193 	for (; *p != '\0'; p++) {
    194 		if (isspace(*p)) {
    195 			while(isspace(*p))
    196 				*p++ = '\0';	/* blast whitespace */
    197 			if (*p == '\0')
    198 				break;
    199 			xargv[i++] = p;
    200 		}
    201 	}
    202 
    203 	/*LINTED*/
    204 	xargv[i++] = (char *)filename;
    205 	xargv[i] = NULL;
    206 
    207 	if (!(editpid = vfork())) {
    208 		if (notsetuid) {
    209 			setgid(getgid());
    210 			setuid(getuid());
    211 		}
    212 		execvp(editor, xargv);
    213 		_exit(1);
    214 	}
    215 	for (;;) {
    216 		editpid = waitpid(editpid, (int *)&pstat, WUNTRACED);
    217 		if (editpid == -1)
    218 			pw_error(editor, 1, 1);
    219 		else if (WIFSTOPPED(pstat))
    220 			raise(WSTOPSIG(pstat));
    221 		else if (WIFEXITED(pstat) && WEXITSTATUS(pstat) == 0)
    222 			break;
    223 		else
    224 			pw_error(editor, 1, 1);
    225 	}
    226 	editpid = -1;
    227 	free(editor);
    228 	free(xargv);
    229 }
    230 
    231 void
    232 pw_prompt()
    233 {
    234 	int c;
    235 
    236 	(void)printf("re-edit the password file? [y]: ");
    237 	(void)fflush(stdout);
    238 	c = getchar();
    239 	if (c != EOF && c != '\n')
    240 		while (getchar() != '\n');
    241 	if (c == 'n')
    242 		pw_error(NULL, 0, 0);
    243 }
    244 
    245 /* for use in pw_copy(). Compare a pw entry to a pw struct. */
    246 static int
    247 pw_equal (buf, pw)
    248 	char *buf;
    249 	struct passwd *pw;
    250 {
    251 	struct passwd buf_pw;
    252 	int len = strlen (buf);
    253 	if (buf[len-1] == '\n')
    254 		buf[len-1] = '\0';
    255 	if (!pw_scan(buf, &buf_pw, NULL))
    256 		return 0;
    257 	return !strcmp(pw->pw_name, buf_pw.pw_name)
    258 		&& pw->pw_uid == buf_pw.pw_uid
    259 		&& pw->pw_gid == buf_pw.pw_gid
    260 		&& !strcmp(pw->pw_class, buf_pw.pw_class)
    261 		&& (long)pw->pw_change == (long)buf_pw.pw_change
    262 		&& (long)pw->pw_expire == (long)buf_pw.pw_expire
    263 		&& !strcmp(pw->pw_gecos, buf_pw.pw_gecos)
    264 		&& !strcmp(pw->pw_dir, buf_pw.pw_dir)
    265 		&& !strcmp(pw->pw_shell, buf_pw.pw_shell);
    266 }
    267 
    268 void
    269 pw_copy(ffd, tfd, pw, old_pw)
    270 	int ffd, tfd;
    271 	struct passwd *pw, *old_pw;
    272 {
    273 	FILE *from, *to;
    274 	int done;
    275 	char *p, buf[8192];
    276 
    277 	if (!(from = fdopen(ffd, "r")))
    278 		pw_error(_PATH_MASTERPASSWD, 1, 1);
    279 	if (!(to = fdopen(tfd, "w")))
    280 		pw_error(_PATH_MASTERPASSWD_LOCK, 1, 1);
    281 
    282 	for (done = 0; fgets(buf, sizeof(buf), from);) {
    283 		if (!strchr(buf, '\n')) {
    284 			warnx("%s: line too long", _PATH_MASTERPASSWD);
    285 			pw_error(NULL, 0, 1);
    286 		}
    287 		if (done) {
    288 			(void)fprintf(to, "%s", buf);
    289 			if (ferror(to))
    290 				goto err;
    291 			continue;
    292 		}
    293 		if (!(p = strchr(buf, ':'))) {
    294 			warnx("%s: corrupted entry", _PATH_MASTERPASSWD);
    295 			pw_error(NULL, 0, 1);
    296 		}
    297 		*p = '\0';
    298 		if (strcmp(buf, pw->pw_name)) {
    299 			*p = ':';
    300 			(void)fprintf(to, "%s", buf);
    301 			if (ferror(to))
    302 				goto err;
    303 			continue;
    304 		}
    305 		*p = ':';
    306 		if (old_pw && !pw_equal(buf, old_pw)) {
    307 			warnx("%s: entry inconsistent",
    308 			      _PATH_MASTERPASSWD);
    309 			pw_error(NULL, 0, 1);
    310 		}
    311 		(void)fprintf(to, "%s:%s:%d:%d:%s:%ld:%ld:%s:%s:%s\n",
    312 		    pw->pw_name, pw->pw_passwd, pw->pw_uid, pw->pw_gid,
    313 		    pw->pw_class, (long)pw->pw_change, (long)pw->pw_expire,
    314 		    pw->pw_gecos, pw->pw_dir, pw->pw_shell);
    315 		done = 1;
    316 		if (ferror(to))
    317 			goto err;
    318 	}
    319 	/* Only append a new entry if real uid is root! */
    320 	if (!done) {
    321 		if (getuid() == 0)
    322 			(void)fprintf(to, "%s:%s:%d:%d:%s:%ld:%ld:%s:%s:%s\n",
    323 			    pw->pw_name, pw->pw_passwd, pw->pw_uid, pw->pw_gid,
    324 			    pw->pw_class, (long)pw->pw_change,
    325 			    (long)pw->pw_expire, pw->pw_gecos, pw->pw_dir,
    326 			    pw->pw_shell);
    327 		else
    328 			warnx("%s: changes not made, no such entry",
    329 			    _PATH_MASTERPASSWD);
    330 	}
    331 
    332 	if (ferror(to))
    333 err:		pw_error(NULL, 1, 1);
    334 	(void)fclose(to);
    335 }
    336 
    337 void
    338 pw_error(name, err, eval)
    339 	const char *name;
    340 	int err, eval;
    341 {
    342 	if (err)
    343 		warn(name);
    344 
    345 	warnx("%s: unchanged", _PATH_MASTERPASSWD);
    346 	pw_abort();
    347 	exit(eval);
    348 }
    349