usr.sbin/rpc.yppasswdd/yppasswdd_server.c

/*
 * Copyright (c) 1995, 1996
 *	Bill Paul <wpaul@ctr.columbia.edu>.  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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by Bill Paul.
 * 4. Neither the name of the author nor the names of any co-contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY Bill Paul 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 Bill Paul 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.
 *
 *	$Id: yppasswdd_server.c,v 1.2 1996/02/24 22:10:42 wpaul Exp $
 */

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
#include <unistd.h>
#include <dirent.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <limits.h>
#include <db.h>
#include <pwd.h>
#include <errno.h>
#include <signal.h>
#include <rpc/rpc.h>
#include <rpcsvc/yp.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/param.h>
struct dom_binding {};
#include <rpcsvc/ypclnt.h>
#include "yppasswdd_extern.h"
#include "yppasswd.h"
#include "yppasswd_private.h"
#include "yppasswd_comm.h"

#ifndef lint
static const char rcsid[] = "$Id: yppasswdd_server.c,v 1.2 1996/02/24 22:10:42 wpaul Exp $";
#endif /* not lint */

char *tempname;

void reaper(sig)
	int sig;
{
	extern pid_t pid;
	extern int pstat;
	int st;

	if (sig > 0) {
		if (sig == SIGCHLD)
			while(wait3(&st, WNOHANG, NULL) > 0) ;
	} else {
		pid = waitpid(pid, &pstat, 0);
	}
	return;
}

void install_reaper(on)
	int on;
{
	if (on) {
		signal(SIGCHLD, reaper);
	} else {
		signal(SIGCHLD, SIG_DFL);
	}
	return;
}

static struct passwd yp_password;

static void copy_yp_pass(p, x, m)
char *p;
int x, m;
{
	register char *t, *s = p;
	static char *buf;

	yp_password.pw_fields = 0;

	buf = (char *)realloc(buf, m + 10);
	bzero(buf, m + 10);

	/* Turn all colons into NULLs */
	while (strchr(s, ':')) {
		s = (strchr(s, ':') + 1);
		*(s - 1)= '\0';
	}

	t = buf;
#define EXPAND(e)       e = t; while ((*t++ = *p++));
        EXPAND(yp_password.pw_name);
	yp_password.pw_fields |= _PWF_NAME;
        EXPAND(yp_password.pw_passwd);
	yp_password.pw_fields |= _PWF_PASSWD;
	yp_password.pw_uid = atoi(p);
        p += (strlen(p) + 1);
	yp_password.pw_fields |= _PWF_UID;
	yp_password.pw_gid = atoi(p);
        p += (strlen(p) + 1);
	yp_password.pw_fields |= _PWF_GID;
	if (x) {
		EXPAND(yp_password.pw_class);
		yp_password.pw_fields |= _PWF_CLASS;
		yp_password.pw_change = atol(p);
		p += (strlen(p) + 1);
		yp_password.pw_fields |= _PWF_CHANGE;
		yp_password.pw_expire = atol(p);
		p += (strlen(p) + 1);
		yp_password.pw_fields |= _PWF_EXPIRE;
	}
        EXPAND(yp_password.pw_gecos);
	yp_password.pw_fields |= _PWF_GECOS;
        EXPAND(yp_password.pw_dir);
	yp_password.pw_fields |= _PWF_DIR;
        EXPAND(yp_password.pw_shell);
	yp_password.pw_fields |= _PWF_SHELL;

	return;
}

static int validchars(arg)
	char *arg;
{
	int i;

	for (i = 0; i < strlen(arg); i++) {
		if (iscntrl(arg[i])) {
			yp_error("string contains a control character");
			return(1);
		}
		if (arg[i] == ':') {
			yp_error("string contains a colon");
			return(1);
		}
		/* Be evil: truncate strings with \n in them silently. */
		if (arg[i] == '\n') {
			arg[i] = '\0';
			return(0);
		}
	}
	return(0);
}

static int validate_master(opw, npw)
	struct passwd *opw;
	struct x_master_passwd *npw;
{

	if (npw->pw_name[0] == '+' || npw->pw_name[0] == '-') {
		yp_error("client tried to modify an NIS entry");
		return(1);
	}

	if (validchars(npw->pw_shell)) {
		yp_error("specified shell contains invalid characters");
		return(1);
	}

	if (validchars(npw->pw_gecos)) {
		yp_error("specified gecos field contains invalid characters");
		return(1);
	}

	if (validchars(npw->pw_passwd)) {
		yp_error("specified password contains invalid characters");
		return(1);
	}
	return(0);
}

static int validate(opw, npw)
	struct passwd *opw;
	struct x_passwd *npw;
{

	if (npw->pw_name[0] == '+' || npw->pw_name[0] == '-') {
		yp_error("client tried to modify an NIS entry");
		return(1);
	}

	if (npw->pw_uid != opw->pw_uid) {
		yp_error("UID mismatch: client says user %s has UID %d",
			 npw->pw_name, npw->pw_uid);
		yp_error("database says user %s has UID %d", opw->pw_name,
			 opw->pw_uid);
		return(1);
	}

	if (npw->pw_gid != opw->pw_gid) {
		yp_error("GID mismatch: client says user %s has GID %d",
			 npw->pw_name, npw->pw_gid);
		yp_error("database says user %s has GID %d", opw->pw_name,
			 opw->pw_gid);
		return(1);
	}

	/*
	 * Don't allow the user to shoot himself in the foot,
	 * even on purpose.
	 */
	if (!ok_shell(npw->pw_shell)) {
		yp_error("%s is not a valid shell", npw->pw_shell);
		return(1);
	}

	if (validchars(npw->pw_shell)) {
		yp_error("specified shell contains invalid characters");
		return(1);
	}

	if (validchars(npw->pw_gecos)) {
		yp_error("specified gecos field contains invalid characters");
		return(1);
	}

	if (validchars(npw->pw_passwd)) {
		yp_error("specified password contains invalid characters");
		return(1);
	}
	return(0);
}

/*
 * Kludge alert:
 * In order to have one rpc.yppasswdd support multiple domains,
 * we have to cheat: we search each directory under /var/yp
 * and try to match the user in each master.passwd.byname
 * map that we find. If the user matches (username, uid and gid
 * all agree), then we use that domain. If we match the user in
 * more than one database, we must abort.
 */
static char *find_domain(pw)
	struct x_passwd *pw;
{
	struct stat statbuf;
	struct dirent *dirp;
	DIR *dird;
	char yp_mapdir[MAXPATHLEN + 2];
	static char domain[YPMAXDOMAIN];
	char *tmp = NULL;
	DBT key, data;
	int hit = 0;

	yp_error("performing multidomain lookup");

	if ((dird = opendir(yp_dir)) == NULL) {
		yp_error("opendir(%s) failed: %s", yp_dir, strerror(errno));
		return(NULL);
	}

	while ((dirp = readdir(dird)) != NULL) {
		snprintf(yp_mapdir, sizeof(yp_mapdir), "%s/%s",
							yp_dir, dirp->d_name);
		if (stat(yp_mapdir, &statbuf) < 0) {
			yp_error("stat(%s) failed: %s", yp_mapdir,
							strerror(errno));
			closedir(dird);
			return(NULL);
		}
		if (S_ISDIR(statbuf.st_mode)) {
			tmp = (char *)dirp->d_name;
			key.data = pw->pw_name;
			key.size = strlen(pw->pw_name);

			if (yp_get_record(tmp,"master.passwd.byname",
			  		&key, &data, 0) != YP_TRUE) {
				continue;
			}
			*(char *)(data.data + data.size) = '\0';
			copy_yp_pass(data.data, 1, data.size);
			if (yp_password.pw_uid == pw->pw_uid &&
			    yp_password.pw_gid == pw->pw_gid) {
				hit++;
				snprintf(domain, YPMAXDOMAIN, "%s", tmp);
			}
		}
	}

	closedir(dird);
	if (hit > 1) {
		yp_error("found same user in two different domains");
		return(NULL);
	} else
		return(&domain);
}

int *
yppasswdproc_update_1_svc(yppasswd *argp, struct svc_req *rqstp)
{
	static int  result;
	struct sockaddr_in *rqhost;
	DBT key, data;
	int rval = 0;
	int pfd, tfd;
	int pid;
	int passwd_changed = 0;
	int shell_changed = 0;
	int gecos_changed = 0;
	char *oldshell = NULL;
	char *oldgecos = NULL;
	char *passfile_hold;
	char passfile_buf[MAXPATHLEN + 2];
	char template[] = "/etc/yppwtmp.XXXXX";
	char *domain = yppasswd_domain;

	/*
	 * Normal user updates always use the 'default' master.passwd file.
	 */

	passfile = passfile_default;
	result = 1;

	rqhost = svc_getcaller(rqstp->rq_xprt);

	if (yp_access(resvport ? "master.passwd.byname" : NULL, rqstp)) {
		yp_error("rejected update request from unauthorized host");
		svcerr_auth(rqstp->rq_xprt, AUTH_BADCRED);
		return(&result);
	}

	/*
	 * Step one: find the user. (It's kinda pointless to
	 * proceed if the user doesn't exist.) We look for the
	 * user in the master.passwd.byname database, _NOT_ by
	 * using getpwent() and friends! We can't use getpwent()
	 * since the NIS master server is not guaranteed to be
	 * configured as an NIS client.
	 */

	if (multidomain) {
		if ((domain = find_domain(&argp->newpw)) == NULL) {
			yp_error("multidomain lookup failed - aborting update");
			return(&result);
		} else
			yp_error("updating user %s in domain %s",
					argp->newpw.pw_name, domain);
	}

	key.data = argp->newpw.pw_name;
	key.size = strlen(argp->newpw.pw_name);

	if ((rval=yp_get_record(domain,"master.passwd.byname",
		  	&key, &data, 0)) != YP_TRUE) {
		if (rval == YP_NOKEY) {
			yp_error("user %s not found in passwd database",
			 	argp->newpw.pw_name);
		} else {
			yp_error("database access error: %s",
			 	yperr_string(rval));
		}
		return(&result);
	}

	/* Nul terminate, please. */
	*(char *)(data.data + data.size) = '\0';

	copy_yp_pass(data.data, 1, data.size);

	/* Step 2: check that the supplied oldpass is valid. */

	if (strcmp(crypt(argp->oldpass, yp_password.pw_passwd),
					yp_password.pw_passwd)) {
		yp_error("rejected change attempt -- bad password");
		yp_error("client address: %s username: %s",
			  inet_ntoa(rqhost->sin_addr),
			  argp->newpw.pw_name);
		return(&result);
	}

	/* Step 3: validate the arguments passed to us by the client. */

	if (validate(&yp_password, &argp->newpw)) {
		yp_error("rejecting change attempt: bad arguments");
		yp_error("client address: %s username: %s",
			 inet_ntoa(rqhost->sin_addr),
			 argp->newpw.pw_name);
		svcerr_decode(rqstp->rq_xprt);
		return(&result);
	}

	/* Step 4: update the user's passwd structure. */

	if (!no_chsh && strcmp(argp->newpw.pw_shell, yp_password.pw_shell)) {
		oldshell = yp_password.pw_shell;
		yp_password.pw_shell = argp->newpw.pw_shell;
		shell_changed++;
	}


	if (!no_chfn && strcmp(argp->newpw.pw_gecos, yp_password.pw_gecos)) {
		oldgecos = yp_password.pw_gecos;
		yp_password.pw_gecos = argp->newpw.pw_gecos;
		gecos_changed++;
	}

	if (strcmp(argp->newpw.pw_passwd, yp_password.pw_passwd)) {
		yp_password.pw_passwd = argp->newpw.pw_passwd;
		passwd_changed++;
	}

	/*
	 * If the caller specified a domain other than our 'default'
	 * domain, change the path to master.passwd accordingly.
	 */

	if (strcmp(domain, yppasswd_domain)) {
		snprintf(passfile_buf, sizeof(passfile_buf),
			"/var/yp/%s/master.passwd", domain);
		passfile = (char *)&passfile_buf;
	}

	/* Step 5: make a new password file with the updated info. */

	if ((pfd = pw_lock()) < 0) {
		return (&result);
	}
	if ((tfd = pw_tmp()) < 0) {
		return (&result);
	}

	if (pw_copy(pfd, tfd, &yp_password)) {
		yp_error("failed to created updated password file -- \
cleaning up and bailing out");
		unlink(tempname);
		return(&result);
	}

	passfile_hold = mktemp((char *)&template);
	rename(passfile, passfile_hold);
	if (strcmp(passfile, _PATH_MASTERPASSWD)) {
		rename(tempname, passfile);
	} else {
		if (pw_mkdb() < 0) {
			yp_error("pwd_mkdb failed");
			return(&result);
		}
	}

	switch((pid = fork())) {
	case 0:
		/* unlink(passfile_hold); */
    		execlp(MAP_UPDATE_PATH, MAP_UPDATE, passfile,
			yppasswd_domain, NULL);
    		yp_error("couldn't exec map update process: %s",
					strerror(errno));
		unlink(passfile);
		rename(passfile_hold, passfile);
    		exit(1);
		break;
	case -1:
		yp_error("fork() failed: %s", strerror(errno));
		return(&result);
		unlink(passfile);
		rename(passfile_hold, passfile);
		break;
	default:
		break;
	}

	if (verbose) {
		yp_error("update completed for user %s (uid %d):",
						argp->newpw.pw_name,
						argp->newpw.pw_uid);

		if (passwd_changed)
			yp_error("password changed");

		if (gecos_changed)
			yp_error("gecos changed ('%s' -> '%s')",
					oldgecos, argp->newpw.pw_gecos);

		if (shell_changed)
			yp_error("shell changed ('%s' -> '%s')",
					oldshell, argp->newpw.pw_shell);
	}

	result = 0;
	return (&result);

}

/*
 * Note that this function performs a little less sanity checking
 * than the last one. Since only the superuser is allowed to use it,
 * it is assumed that the caller knows what he's doing.
 */
static int update_master(master_yppasswd *argp)
{
	int result;
	int pfd, tfd;
	int pid;
	int rval = 0;
	DBT key, data;
	char *passfile_hold;
	char passfile_buf[MAXPATHLEN + 2];
	char template[] = "/etc/yppwtmp.XXXXX";

	result = 1;
	passfile = passfile_default;

	key.data = argp->newpw.pw_name;
	key.size = strlen(argp->newpw.pw_name);

	/*
	 * The superuser may add entries to the passwd maps if
	 * rpc.yppasswdd is started with the -a flag. Paranoia
	 * prevents me from allowing additions by default.
	 */
	if ((rval = yp_get_record(argp->domain, "master.passwd.byname",
			  &key, &data, 0)) != YP_TRUE) {
		if (rval == YP_NOKEY) {
			yp_error("user %s not found in passwd database",
				 argp->newpw.pw_name);
			if (allow_additions)
				yp_error("notice: adding user %s to \
master.passwd database for domain %s", argp->newpw.pw_name, argp->domain);
			else
				yp_error("restart %s with the -a flag to \
allow additions to be made to the password database", progname);
		} else {
			yp_error("database access error: %s",
				 yperr_string(rval));
		}
		if (!allow_additions)
			return(result);
	} else {

		/* Nul terminate, please. */
		*(char *)(data.data + data.size) = '\0';

		copy_yp_pass(data.data, 1, data.size);
	}

	/*
	 * Perform a small bit of sanity checking.
	 */
	if (validate_master(rval == YP_TRUE ? &yp_password:NULL,&argp->newpw)){
		yp_error("rejecting update attempt for %s: bad arguments",
			 argp->newpw.pw_name);
		return(result);
	}

	/*
	 * If the caller specified a domain other than our 'default'
	 * domain, change the path to master.passwd accordingly.
	 */

	if (strcmp(argp->domain, yppasswd_domain)) {
		snprintf(passfile_buf, sizeof(passfile_buf),
			"/var/yp/%s/master.passwd", argp->domain);
		passfile = (char *)&passfile_buf;
	}

	if ((pfd = pw_lock()) < 0) {
		return (result);
	}
	if ((tfd = pw_tmp()) < 0) {
		return (result);
	}

	if (pw_copy(pfd, tfd, (struct passwd  *)&argp->newpw)) {
		yp_error("failed to created updated password file -- \
cleaning up and bailing out");
		unlink(tempname);
		return(result);
	}

	passfile_hold = mktemp((char *)&template);
	rename(passfile, passfile_hold);
	if (strcmp(passfile, _PATH_MASTERPASSWD)) {
		rename(tempname, passfile);
	} else {
		if (pw_mkdb() < 0) {
			yp_error("pwd_mkdb failed");
			return(result);
		}
	}

	switch((pid = fork())) {
	case 0:
		close(yp_sock);
    		execlp(MAP_UPDATE_PATH, MAP_UPDATE, passfile,
			argp->domain, NULL);
    		yp_error("couldn't exec map update process: %s",
					strerror(errno));
		unlink(passfile);
		rename(passfile_hold, passfile);
    		exit(1);
		break;
	case -1:
		yp_error("fork() failed: %s", strerror(errno));
		unlink(passfile);
		rename(passfile_hold, passfile);
		return(result);
		break;
	default:
		break;
	}

	yp_error("performed update of user %s (uid %d) domain %s",
						argp->newpw.pw_name,
						argp->newpw.pw_uid,
						argp->domain);

	result = 0;
	return(result);
}

/*
 * Pseudo-dispatcher for private 'superuser-only' update handler.
 */
void do_master()
{
	struct master_yppasswd *pw;

	if ((pw = getdat(yp_sock)) == NULL) {
		return;
	}

	yp_error("received update request from superuser on localhost");
	sendresp(update_master(pw));

	/* Remember to free args. */
	xdr_free(xdr_master_yppasswd, (char *)pw);

	return;
}