HardenedBSD/usr.sbin/pwd_mkdb/pwd_mkdb.c

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1991, 1993, 1994
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#if 0
#ifndef lint
static const char copyright[] =
"@(#) Copyright (c) 1991, 1993, 1994\n\
	The Regents of the University of California.  All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)pwd_mkdb.c	8.5 (Berkeley) 4/20/94";
#endif /* not lint */
#endif

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/param.h>
#include <sys/endian.h>
#include <sys/stat.h>
#include <arpa/inet.h>

#include <db.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <limits.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "pw_scan.h"

#define	INSECURE	1
#define	SECURE		2
#define	PERM_INSECURE	(S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH)
#define	PERM_SECURE	(S_IRUSR|S_IWUSR)
#define LEGACY_VERSION(x)  _PW_VERSIONED(x, 3)
#define CURRENT_VERSION(x) _PW_VERSIONED(x, 4)

static HASHINFO openinfo = {
	4096,		/* bsize */
	32,		/* ffactor */
	256,		/* nelem */
	2048 * 1024,	/* cachesize */
	NULL,		/* hash() */
	BIG_ENDIAN	/* lorder */
};

static enum state { FILE_INSECURE, FILE_SECURE, FILE_ORIG } clean;
static struct passwd pwd;			/* password structure */
static char *pname;				/* password file name */
static char prefix[MAXPATHLEN];

static int is_comment;	/* flag for comments */
static char line[LINE_MAX];

void	cleanup(void);
void	error(const char *);
void	cp(char *, char *, mode_t mode);
void	mv(char *, char *);
int	scan(FILE *, struct passwd *);
static void	usage(void);

int
main(int argc, char *argv[])
{
	static char verskey[] = _PWD_VERSION_KEY;
	char version = _PWD_CURRENT_VERSION;
	DB *dp, *sdp, *pw_db;
	DBT data, sdata, key;
	FILE *fp, *oldfp;
	sigset_t set;
	int ch, cnt, ypcnt, makeold, tfd, yp_enabled = 0;
	unsigned int len;
	uint32_t store;
	const char *t;
	char *p;
	char buf[MAX(MAXPATHLEN, LINE_MAX * 2)], tbuf[1024];
	char sbuf[MAX(MAXPATHLEN, LINE_MAX * 2)];
	char buf2[MAXPATHLEN];
	char sbuf2[MAXPATHLEN];
	char *username;
	u_int method, methoduid;
	int Cflag, dflag, iflag;
	int nblock = 0;

	iflag = dflag = Cflag = 0;
	strcpy(prefix, _PATH_PWD);
	makeold = 0;
	username = NULL;
	oldfp = NULL;
	while ((ch = getopt(argc, argv, "CNd:ips:u:v")) != -1)
		switch(ch) {
		case 'C':                       /* verify only */
			Cflag = 1;
			break;
		case 'N':			/* do not wait for lock	*/
			nblock = LOCK_NB;	/* will fail if locked */
			break;
		case 'd':
			dflag++;
			strlcpy(prefix, optarg, sizeof(prefix));
			break;
		case 'i':
			iflag++;
			break;
		case 'p':			/* create V7 "file.orig" */
			makeold = 1;
			break;
		case 's':			/* change default cachesize */
			openinfo.cachesize = atoi(optarg) * 1024 * 1024;
			break;
		case 'u':			/* only update this record */
			username = optarg;
			break;
		case 'v':                       /* backward compatible */
			break;
		default:
			usage();
		}
	argc -= optind;
	argv += optind;

	if (argc != 1 || (username && (*username == '+' || *username == '-')))
		usage();

	/*
	 * This could be changed to allow the user to interrupt.
	 * Probably not worth the effort.
	 */
	sigemptyset(&set);
	sigaddset(&set, SIGTSTP);
	sigaddset(&set, SIGHUP);
	sigaddset(&set, SIGINT);
	sigaddset(&set, SIGQUIT);
	sigaddset(&set, SIGTERM);
	(void)sigprocmask(SIG_BLOCK, &set, (sigset_t *)NULL);

	/* We don't care what the user wants. */
	(void)umask(0);

	pname = *argv;

	/*
	 * Open and lock the original password file.  We have to check
	 * the hardlink count after we get the lock to handle any potential
	 * unlink/rename race.
	 *
	 * This lock is necessary when someone runs pwd_mkdb manually, directly
	 * on master.passwd, to handle the case where a user might try to
	 * change his password while pwd_mkdb is running. 
	 */
	for (;;) {
		struct stat st;

		if (!(fp = fopen(pname, "r")))
			error(pname);
		if (flock(fileno(fp), LOCK_EX|nblock) < 0 && !(dflag && iflag))
			error("flock");
		if (fstat(fileno(fp), &st) < 0)
			error(pname);
		if (st.st_nlink != 0)
			break;
		fclose(fp);
		fp = NULL;
	}

	/* check only if password database is valid */
	if (Cflag) {
		while (scan(fp, &pwd))
			if (!is_comment && strlen(pwd.pw_name) >= MAXLOGNAME) {
				warnx("%s: username too long", pwd.pw_name);
				exit(1);
			}
		exit(0);
	}

	/* Open the temporary insecure password database. */
	(void)snprintf(buf, sizeof(buf), "%s/%s.tmp", prefix, _MP_DB);
	(void)snprintf(sbuf, sizeof(sbuf), "%s/%s.tmp", prefix, _SMP_DB);
	if (username) {
		int use_version;

		(void)snprintf(buf2, sizeof(buf2), "%s/%s", prefix, _MP_DB);
		(void)snprintf(sbuf2, sizeof(sbuf2), "%s/%s", prefix, _SMP_DB);

		clean = FILE_INSECURE;
		cp(buf2, buf, PERM_INSECURE);
		dp = dbopen(buf,
		    O_RDWR|O_EXCL, PERM_INSECURE, DB_HASH, &openinfo);
		if (dp == NULL)
			error(buf);

		clean = FILE_SECURE;
		cp(sbuf2, sbuf, PERM_SECURE);
		sdp = dbopen(sbuf,
		    O_RDWR|O_EXCL, PERM_SECURE, DB_HASH, &openinfo);
		if (sdp == NULL)
			error(sbuf);

		/*
		 * Do some trouble to check if we should store this users 
		 * uid. Don't use getpwnam/getpwuid as that interferes 
		 * with NIS.
		 */
		pw_db = dbopen(_PATH_MP_DB, O_RDONLY, 0, DB_HASH, NULL);
		if (!pw_db)
			error(_MP_DB);

		key.data = verskey;
		key.size = sizeof(verskey)-1;
		if ((pw_db->get)(pw_db, &key, &data, 0) == 0)
			use_version = *(unsigned char *)data.data;
		else
			use_version = 3;
		buf[0] = _PW_VERSIONED(_PW_KEYBYNAME, use_version);
		len = strlen(username);

		/* Only check that username fits in buffer */
		memmove(buf + 1, username, MIN(len, sizeof(buf) - 1));
		key.data = (u_char *)buf;
		key.size = len + 1;
		if ((pw_db->get)(pw_db, &key, &data, 0) == 0) {
			p = (char *)data.data;

			/* jump over pw_name and pw_passwd, to get to pw_uid */
			while (*p++)
				;
			while (*p++)
				;

			buf[0] = _PW_VERSIONED(_PW_KEYBYUID, use_version);
			memmove(buf + 1, p, sizeof(store));
			key.data = (u_char *)buf;
			key.size = sizeof(store) + 1;

			if ((pw_db->get)(pw_db, &key, &data, 0) == 0) {
				/* First field of data.data holds pw_pwname */
				if (!strcmp(data.data, username))
					methoduid = 0;
				else
					methoduid = R_NOOVERWRITE;
			} else {
				methoduid = R_NOOVERWRITE;
			}
		} else {
			methoduid = R_NOOVERWRITE;
		}
		if ((pw_db->close)(pw_db))
			error("close pw_db");
		method = 0;
	} else {
		dp = dbopen(buf,
		    O_RDWR|O_CREAT|O_EXCL, PERM_INSECURE, DB_HASH, &openinfo);
		if (dp == NULL)
			error(buf);
		clean = FILE_INSECURE;

		sdp = dbopen(sbuf,
		    O_RDWR|O_CREAT|O_EXCL, PERM_SECURE, DB_HASH, &openinfo);
		if (sdp == NULL)
			error(sbuf);
		clean = FILE_SECURE;

		method = R_NOOVERWRITE;
		methoduid = R_NOOVERWRITE;
	}

	/*
	 * Open file for old password file.  Minor trickiness -- don't want to
	 * chance the file already existing, since someone (stupidly) might
	 * still be using this for permission checking.  So, open it first and
	 * fdopen the resulting fd.  The resulting file should be readable by
	 * everyone.
	 */
	if (makeold) {
		(void)snprintf(buf, sizeof(buf), "%s.orig", pname);
		if ((tfd = open(buf,
		    O_WRONLY|O_CREAT|O_EXCL, PERM_INSECURE)) < 0)
			error(buf);
		if ((oldfp = fdopen(tfd, "w")) == NULL)
			error(buf);
		clean = FILE_ORIG;
	}

	/*
	 * The databases actually contain three copies of the original data.
	 * Each password file entry is converted into a rough approximation
	 * of a ``struct passwd'', with the strings placed inline.  This
	 * object is then stored as the data for three separate keys.  The
	 * first key * is the pw_name field prepended by the _PW_KEYBYNAME
	 * character.  The second key is the pw_uid field prepended by the
	 * _PW_KEYBYUID character.  The third key is the line number in the
	 * original file prepended by the _PW_KEYBYNUM character.  (The special
	 * characters are prepended to ensure that the keys do not collide.)
	 */
	/* In order to transition this file into a machine-independent
	 * form, we have to change the format of entries.  However, since
	 * older binaries will still expect the old MD format entries, we 
	 * create those as usual and use versioned tags for the new entries.
	 */
	if (username == NULL) {
		/* Do not add the VERSION tag when updating a single
		 * user.  When operating on `old format' databases, this
		 * would result in applications `seeing' only the updated
		 * entries.
		 */
		key.data = verskey;
		key.size = sizeof(verskey)-1;
		data.data = &version;
		data.size = 1;
		if ((dp->put)(dp, &key, &data, 0) == -1)
			error("put");
		if ((sdp->put)(sdp, &key, &data, 0) == -1)
			error("put");
	}
	ypcnt = 0;
	data.data = (u_char *)buf;
	sdata.data = (u_char *)sbuf;
	key.data = (u_char *)tbuf;
	for (cnt = 1; scan(fp, &pwd); ++cnt) {
		if (!is_comment && 
		    (pwd.pw_name[0] == '+' || pwd.pw_name[0] == '-')) {
			yp_enabled = 1;
			ypcnt++;
		}
		if (is_comment)
			--cnt;
#define	COMPACT(e)	t = e; while ((*p++ = *t++));
#define SCALAR(e)	store = htonl((uint32_t)(e));      \
			memmove(p, &store, sizeof(store)); \
			p += sizeof(store);
#define	LSCALAR(e)	store = HTOL((uint32_t)(e));       \
			memmove(p, &store, sizeof(store)); \
			p += sizeof(store);
#define	HTOL(e)		(openinfo.lorder == BYTE_ORDER ? \
			(uint32_t)(e) : \
			bswap32((uint32_t)(e)))
		if (!is_comment && 
		    (!username || (strcmp(username, pwd.pw_name) == 0))) {
			/* Create insecure data. */
			p = buf;
			COMPACT(pwd.pw_name);
			COMPACT("*");
			SCALAR(pwd.pw_uid);
			SCALAR(pwd.pw_gid);
			SCALAR(pwd.pw_change);
			COMPACT(pwd.pw_class);
			COMPACT(pwd.pw_gecos);
			COMPACT(pwd.pw_dir);
			COMPACT(pwd.pw_shell);
			SCALAR(pwd.pw_expire);
			SCALAR(pwd.pw_fields);
			data.size = p - buf;

			/* Create secure data. */
			p = sbuf;
			COMPACT(pwd.pw_name);
			COMPACT(pwd.pw_passwd);
			SCALAR(pwd.pw_uid);
			SCALAR(pwd.pw_gid);
			SCALAR(pwd.pw_change);
			COMPACT(pwd.pw_class);
			COMPACT(pwd.pw_gecos);
			COMPACT(pwd.pw_dir);
			COMPACT(pwd.pw_shell);
			SCALAR(pwd.pw_expire);
			SCALAR(pwd.pw_fields);
			sdata.size = p - sbuf;

			/* Store insecure by name. */
			tbuf[0] = CURRENT_VERSION(_PW_KEYBYNAME);
			len = strlen(pwd.pw_name);
			memmove(tbuf + 1, pwd.pw_name, len);
			key.size = len + 1;
			if ((dp->put)(dp, &key, &data, method) == -1)
				error("put");

			/* Store insecure by number. */
			tbuf[0] = CURRENT_VERSION(_PW_KEYBYNUM);
			store = htonl(cnt);
			memmove(tbuf + 1, &store, sizeof(store));
			key.size = sizeof(store) + 1;
			if ((dp->put)(dp, &key, &data, method) == -1)
				error("put");

			/* Store insecure by uid. */
			tbuf[0] = CURRENT_VERSION(_PW_KEYBYUID);
			store = htonl(pwd.pw_uid);
			memmove(tbuf + 1, &store, sizeof(store));
			key.size = sizeof(store) + 1;
			if ((dp->put)(dp, &key, &data, methoduid) == -1)
				error("put");

			/* Store secure by name. */
			tbuf[0] = CURRENT_VERSION(_PW_KEYBYNAME);
			len = strlen(pwd.pw_name);
			memmove(tbuf + 1, pwd.pw_name, len);
			key.size = len + 1;
			if ((sdp->put)(sdp, &key, &sdata, method) == -1)
				error("put");

			/* Store secure by number. */
			tbuf[0] = CURRENT_VERSION(_PW_KEYBYNUM);
			store = htonl(cnt);
			memmove(tbuf + 1, &store, sizeof(store));
			key.size = sizeof(store) + 1;
			if ((sdp->put)(sdp, &key, &sdata, method) == -1)
				error("put");

			/* Store secure by uid. */
			tbuf[0] = CURRENT_VERSION(_PW_KEYBYUID);
			store = htonl(pwd.pw_uid);
			memmove(tbuf + 1, &store, sizeof(store));
			key.size = sizeof(store) + 1;
			if ((sdp->put)(sdp, &key, &sdata, methoduid) == -1)
				error("put");

			/* Store insecure and secure special plus and special minus */
			if (pwd.pw_name[0] == '+' || pwd.pw_name[0] == '-') {
				tbuf[0] = CURRENT_VERSION(_PW_KEYYPBYNUM);
				store = htonl(ypcnt);
				memmove(tbuf + 1, &store, sizeof(store));
				key.size = sizeof(store) + 1;
				if ((dp->put)(dp, &key, &data, method) == -1)
					error("put");
				if ((sdp->put)(sdp, &key, &sdata, method) == -1)
					error("put");
			}
		}
		/* Create original format password file entry */
		if (is_comment && makeold){	/* copy comments */
			if (fprintf(oldfp, "%s\n", line) < 0)
				error("write old");
		} else if (makeold) {
			char uidstr[20];
			char gidstr[20];

			snprintf(uidstr, sizeof(uidstr), "%u", pwd.pw_uid);
			snprintf(gidstr, sizeof(gidstr), "%u", pwd.pw_gid);

			if (fprintf(oldfp, "%s:*:%s:%s:%s:%s:%s\n",
			    pwd.pw_name, pwd.pw_fields & _PWF_UID ? uidstr : "",
			    pwd.pw_fields & _PWF_GID ? gidstr : "",
			    pwd.pw_gecos, pwd.pw_dir, pwd.pw_shell) < 0)
				error("write old");
		}
	}
	/* If YP enabled, set flag. */
	if (yp_enabled) {
		buf[0] = yp_enabled + 2;
		data.size = 1;
		key.size = 1;
		tbuf[0] = CURRENT_VERSION(_PW_KEYYPENABLED);
		if ((dp->put)(dp, &key, &data, method) == -1)
			error("put");
		if ((sdp->put)(sdp, &key, &data, method) == -1)
			error("put");
	}

	if ((dp->close)(dp) == -1)
		error("close");
	if ((sdp->close)(sdp) == -1)
		error("close");
	if (makeold) {
		(void)fflush(oldfp);
		if (fclose(oldfp) == EOF)
			error("close old");
	}

	/* Set master.passwd permissions, in case caller forgot. */
	(void)fchmod(fileno(fp), S_IRUSR|S_IWUSR);

	/* Install as the real password files. */
	(void)snprintf(buf, sizeof(buf), "%s/%s.tmp", prefix, _MP_DB);
	(void)snprintf(buf2, sizeof(buf2), "%s/%s", prefix, _MP_DB);
	mv(buf, buf2);
	(void)snprintf(buf, sizeof(buf), "%s/%s.tmp", prefix, _SMP_DB);
	(void)snprintf(buf2, sizeof(buf2), "%s/%s", prefix, _SMP_DB);
	mv(buf, buf2);
	if (makeold) {
		(void)snprintf(buf2, sizeof(buf2), "%s/%s", prefix, _PASSWD);
		(void)snprintf(buf, sizeof(buf), "%s.orig", pname);
		mv(buf, buf2);
	}
	/*
	 * Move the master password LAST -- chpass(1), passwd(1) and vipw(8)
	 * all use flock(2) on it to block other incarnations of themselves.
	 * The rename means that everything is unlocked, as the original file
	 * can no longer be accessed.
	 */
	(void)snprintf(buf, sizeof(buf), "%s/%s", prefix, _MASTERPASSWD);
	mv(pname, buf);

	/*
	 * Close locked password file after rename()
	 */
	if (fclose(fp) == EOF)
		error("close fp");

	exit(0);
}

int
scan(FILE *fp, struct passwd *pw)
{
	static int lcnt;
	size_t len;
	char *p;

	p = fgetln(fp, &len);
	if (p == NULL)
		return (0);
	++lcnt;
	/*
	 * ``... if I swallow anything evil, put your fingers down my
	 * throat...''
	 *	-- The Who
	 */
	if (len > 0 && p[len - 1] == '\n')
		len--;
	if (len >= sizeof(line) - 1) {
		warnx("line #%d too long", lcnt);
		goto fmt;
	}
	memcpy(line, p, len);
	line[len] = '\0';

	/* 
	 * Ignore comments: ^[ \t]*#
	 */
	for (p = line; *p != '\0'; p++)
		if (*p != ' ' && *p != '\t')
			break;
	if (*p == '#' || *p == '\0') {
		is_comment = 1;
		return(1);
	} else
		is_comment = 0;

	if (!__pw_scan(line, pw, _PWSCAN_WARN|_PWSCAN_MASTER)) {
		warnx("at line #%d", lcnt);
fmt:		errno = EFTYPE;	/* XXX */
		error(pname);
	}

	return (1);
}

void                    
cp(char *from, char *to, mode_t mode)              
{               
	static char buf[MAXBSIZE];
	int from_fd, rcount, to_fd, wcount;

	if ((from_fd = open(from, O_RDONLY, 0)) < 0)
		error(from);
	if ((to_fd = open(to, O_WRONLY|O_CREAT|O_EXCL, mode)) < 0)
		error(to);
	while ((rcount = read(from_fd, buf, MAXBSIZE)) > 0) {
		wcount = write(to_fd, buf, rcount);
		if (rcount != wcount || wcount == -1) {
			int sverrno = errno;

			(void)snprintf(buf, sizeof(buf), "%s to %s", from, to);
			errno = sverrno;
			error(buf);
		}
	}
	if (rcount < 0) {
		int sverrno = errno;

		(void)snprintf(buf, sizeof(buf), "%s to %s", from, to);
		errno = sverrno;
		error(buf);
	}
}


void
mv(char *from, char *to)
{
	char buf[MAXPATHLEN];
	char *to_dir;
	int to_dir_fd = -1;

	/*
	 * Make sure file is safe on disk. To improve performance we will call
	 * fsync() to the directory where file lies
	 */
	if (rename(from, to) != 0 ||
	    (to_dir = dirname(to)) == NULL ||
	    (to_dir_fd = open(to_dir, O_RDONLY|O_DIRECTORY)) == -1 ||
	    fsync(to_dir_fd) != 0) {
		int sverrno = errno;
		(void)snprintf(buf, sizeof(buf), "%s to %s", from, to);
		errno = sverrno;
		if (to_dir_fd != -1)
			close(to_dir_fd);
		error(buf);
	}

	if (to_dir_fd != -1)
		close(to_dir_fd);
}

void
error(const char *name)
{

	warn("%s", name);
	cleanup();
	exit(1);
}

void
cleanup(void)
{
	char buf[MAXPATHLEN];

	switch(clean) {
	case FILE_ORIG:
		(void)snprintf(buf, sizeof(buf), "%s.orig", pname);
		(void)unlink(buf);
		/* FALLTHROUGH */
	case FILE_SECURE:
		(void)snprintf(buf, sizeof(buf), "%s/%s.tmp", prefix, _SMP_DB);
		(void)unlink(buf);
		/* FALLTHROUGH */
	case FILE_INSECURE:
		(void)snprintf(buf, sizeof(buf), "%s/%s.tmp", prefix, _MP_DB);
		(void)unlink(buf);
	}
}

static void
usage(void)
{

	(void)fprintf(stderr,
"usage: pwd_mkdb [-BCiLNp] [-d directory] [-s cachesize] [-u username] file\n");
	exit(1);
}