freebsd-skq/usr.sbin/rpc.yppasswdd/yppasswdd_server.c
2002-05-15 09:20:06 +00:00

833 lines
21 KiB
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.
*/
#ifndef lint
static const char rcsid[] =
"$FreeBSD$";
#endif /* not lint */
#include <sys/param.h>
#include <sys/fcntl.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <ctype.h>
#include <db.h>
#include <dirent.h>
#include <errno.h>
#include <limits.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <libgen.h>
#include <libutil.h>
#include <rpc/rpc.h>
#include <rpcsvc/yp.h>
struct dom_binding;
#include <rpcsvc/ypclnt.h>
#include "yppasswdd_extern.h"
#include "yppasswd.h"
#include "yppasswd_private.h"
#include "ypxfr_extern.h"
#include "yp_extern.h"
static struct passwd yp_password;
static void
copy_yp_pass(char *p, int x, int m)
{
char *t, *s = p;
static char *buf;
yp_password.pw_fields = 0;
buf = 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(char *arg)
{
size_t 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(struct passwd *opw __unused, 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(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 ((uid_t)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 ((gid_t)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(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 == (uid_t)pw->pw_uid &&
yp_password.pw_gid == (gid_t)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((char *)&domain);
}
static const char *maps[] = {
"master.passwd.byname",
"master.passwd.byuid",
"passwd.byname",
"passwd.byuid"
};
static const char *formats[] = {
"%s:%s:%d:%d:%s:%ld:%ld:%s:%s:%s",
"%s:%s:%d:%d:%s:%ld:%ld:%s:%s:%s",
"%s:%s:%d:%d:%s:%s:%s",
"%s:%s:%d:%d:%s:%s:%s"
};
static int
update_inplace(struct passwd *pw, char *domain)
{
DB *dbp = NULL;
DBT key = { NULL, 0 };
DBT data = { NULL, 0 };
char pwbuf[YPMAXRECORD];
char keybuf[20];
int i;
char *ptr = NULL;
static char yp_last[] = "YP_LAST_MODIFIED";
char yplastbuf[YPMAXRECORD];
snprintf(yplastbuf, sizeof yplastbuf, "%llu",
(unsigned long long)time(NULL));
for (i = 0; i < 4; i++) {
if (i % 2) {
snprintf(keybuf, sizeof keybuf,
"%llu", (unsigned long long)pw->pw_uid);
key.data = &keybuf;
key.size = strlen(keybuf);
} else {
key.data = pw->pw_name;
key.size = strlen(pw->pw_name);
}
/*
* XXX The passwd.byname and passwd.byuid maps come in
* two flavors: secure and insecure. The secure version
* has a '*' in the password field whereas the insecure one
* has a real crypted password. The maps will be insecure
* if they were built with 'unsecure = TRUE' enabled in
* /var/yp/Makefile, but we'd have no way of knowing if
* this has been done unless we were to try parsing the
* Makefile, which is a disgusting thought. Instead, we
* read the records from the maps, skip to the first ':'
* in them, and then look at the character immediately
* following it. If it's an '*' then the map is 'secure'
* and we must not insert a real password into the pw_passwd
* field. If it's not an '*', then we put the real crypted
* password in.
*/
if (yp_get_record(domain,maps[i],&key,&data,1) != YP_TRUE) {
yp_error("couldn't read %s/%s: %s", domain,
maps[i], strerror(errno));
return(1);
}
if ((ptr = strchr(data.data, ':')) == NULL) {
yp_error("no colon in passwd record?!");
return(1);
}
/*
* XXX Supposing we have more than one user with the same
* UID? (Or more than one user with the same name?) We could
* end up modifying the wrong record if were not careful.
*/
if (i % 2) {
if (strncmp(data.data, pw->pw_name,
strlen(pw->pw_name))) {
yp_error("warning: found entry for UID %d \
in map %s@%s with wrong name (%.*s)", pw->pw_uid, maps[i], domain,
(int)(ptr - (char *)data.data),
(char *)data.data);
yp_error("there may be more than one user \
with the same UID - continuing");
continue;
}
} else {
/*
* We're really being ultra-paranoid here.
* This is generally a 'can't happen' condition.
*/
snprintf(pwbuf, sizeof pwbuf, ":%d:%d:", pw->pw_uid,
pw->pw_gid);
if (!strstr(data.data, pwbuf)) {
yp_error("warning: found entry for user %s \
in map %s@%s with wrong UID", pw->pw_name, maps[i], domain);
yp_error("there may be more than one user \
with the same name - continuing");
continue;
}
}
if (i < 2) {
snprintf(pwbuf, sizeof pwbuf, formats[i],
pw->pw_name, pw->pw_passwd, pw->pw_uid,
pw->pw_gid, pw->pw_class, pw->pw_change,
pw->pw_expire, pw->pw_gecos, pw->pw_dir,
pw->pw_shell);
} else {
snprintf(pwbuf, sizeof pwbuf, formats[i],
pw->pw_name, *(ptr+1) == '*' ? "*" : pw->pw_passwd,
pw->pw_uid, pw->pw_gid, pw->pw_gecos, pw->pw_dir,
pw->pw_shell);
}
#define FLAGS O_RDWR|O_CREAT
if ((dbp = yp_open_db_rw(domain, maps[i], FLAGS)) == NULL) {
yp_error("couldn't open %s/%s r/w: %s",domain,
maps[i],strerror(errno));
return(1);
}
data.data = pwbuf;
data.size = strlen(pwbuf);
if (yp_put_record(dbp, &key, &data, 1) != YP_TRUE) {
yp_error("failed to update record in %s/%s", domain,
maps[i]);
(void)(dbp->close)(dbp);
return(1);
}
key.data = yp_last;
key.size = strlen(yp_last);
data.data = (char *)&yplastbuf;
data.size = strlen(yplastbuf);
if (yp_put_record(dbp, &key, &data, 1) != YP_TRUE) {
yp_error("failed to update timestamp in %s/%s", domain,
maps[i]);
(void)(dbp->close)(dbp);
return(1);
}
(void)(dbp->close)(dbp);
}
return(0);
}
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 *domain = yppasswd_domain;
static struct sockaddr_in clntaddr;
static struct timeval t_saved, t_test;
/*
* Normal user updates always use the 'default' master.passwd file.
*/
passfile = passfile_default;
result = 1;
rqhost = svc_getcaller(rqstp->rq_xprt);
gettimeofday(&t_test, NULL);
if (!bcmp(rqhost, &clntaddr, sizeof *rqhost) &&
t_test.tv_sec > t_saved.tv_sec &&
t_test.tv_sec - t_saved.tv_sec < 300) {
bzero(&clntaddr, sizeof clntaddr);
bzero(&t_saved, sizeof t_saved);
return(NULL);
}
bcopy(rqhost, &clntaddr, sizeof clntaddr);
gettimeofday(&t_saved, NULL);
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;
yp_password.pw_change = 0;
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),
"%s/%s/master.passwd", yp_dir, domain);
passfile = (char *)&passfile_buf;
}
/* Step 5: make a new password file with the updated info. */
if (pw_init(dirname(passfile), passfile)) {
yp_error("pw_init() failed");
return &result;
}
if ((pfd = pw_lock()) == -1) {
pw_fini();
yp_error("pw_lock() failed");
return &result;
}
if ((tfd = pw_tmp(-1)) == -1) {
pw_fini();
yp_error("pw_tmp() failed");
return &result;
}
if (pw_copy(pfd, tfd, &yp_password, NULL) == -1) {
pw_fini();
yp_error("pw_copy() failed");
return &result;
}
if (pw_mkdb(yp_password.pw_name) == -1) {
pw_fini();
yp_error("pw_mkdb() failed");
return &result;
}
pw_fini();
if (inplace) {
if ((rval = update_inplace(&yp_password, domain))) {
yp_error("inplace update failed -- rebuilding maps");
}
}
switch ((pid = fork())) {
case 0:
if (inplace && !rval) {
execlp(MAP_UPDATE_PATH, MAP_UPDATE, passfile,
yppasswd_domain, "pushpw", (char *)NULL);
} else {
execlp(MAP_UPDATE_PATH, MAP_UPDATE, passfile,
yppasswd_domain, (char *)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:
unlink(passfile_hold);
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.
*/
int *
yppasswdproc_update_master_1_svc(master_yppasswd *argp,
struct svc_req *rqstp)
{
static int result;
int pfd, tfd;
int pid;
uid_t uid;
int rval = 0;
DBT key, data;
char *passfile_hold;
char passfile_buf[MAXPATHLEN + 2];
struct sockaddr_in *rqhost;
SVCXPRT *transp;
result = 1;
transp = rqstp->rq_xprt;
/*
* NO AF_INET CONNETCIONS ALLOWED!
*/
rqhost = svc_getcaller(transp);
if (rqhost->sin_family != AF_UNIX) {
yp_error("Alert! %s/%d attempted to use superuser-only \
procedure!\n", inet_ntoa(rqhost->sin_addr), rqhost->sin_port);
svcerr_auth(transp, AUTH_BADCRED);
return(&result);
}
if (rqstp->rq_cred.oa_flavor != AUTH_SYS) {
yp_error("caller didn't send proper credentials");
svcerr_auth(transp, AUTH_BADCRED);
return(&result);
}
if (__rpc_get_local_uid(transp, &uid) < 0) {
yp_error("caller didn't send proper credentials");
svcerr_auth(transp, AUTH_BADCRED);
return(&result);
}
if (uid) {
yp_error("caller euid is %d, expecting 0 -- rejecting request",
uid);
svcerr_auth(rqstp->rq_xprt, AUTH_BADCRED);
return(&result);
}
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 rpc.yppasswdd with the -a flag to \
allow additions to be made to the password database");
} 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),
"%s/%s/master.passwd", yp_dir, argp->domain);
passfile = (char *)&passfile_buf;
}
if (pw_init(dirname(passfile), passfile)) {
yp_error("pw_init() failed");
return &result;
}
if ((pfd = pw_lock()) == -1) {
pw_fini();
yp_error("pw_lock() failed");
return &result;
}
if ((tfd = pw_tmp(-1)) == -1) {
pw_fini();
yp_error("pw_tmp() failed");
return &result;
}
if (pw_copy(pfd, tfd, (struct passwd *)&argp->newpw, NULL) == -1) {
pw_fini();
yp_error("pw_copy() failed");
return &result;
}
if (pw_mkdb(argp->newpw.pw_name) == -1) {
pw_fini();
yp_error("pw_mkdb() failed");
return &result;
}
pw_fini();
if (inplace) {
if ((rval = update_inplace((struct passwd *)&argp->newpw,
argp->domain))) {
yp_error("inplace update failed -- rebuilding maps");
}
}
switch ((pid = fork())) {
case 0:
if (inplace && !rval) {
execlp(MAP_UPDATE_PATH, MAP_UPDATE, passfile,
argp->domain, "pushpw", (char *)NULL);
} else {
execlp(MAP_UPDATE_PATH, MAP_UPDATE, passfile,
argp->domain, (char *)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:
unlink(passfile_hold);
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);
}