freebsd-dev/lib/libc/gen/getpwent.c
Mike Pritchard 70520b51b9 Getpwent() and getservent() can wind up calling free() with
an invalid pointer if a call to yp_first() fails.  Closes PR # 964,
and possibly # 952.
1996-01-29 20:16:30 +00:00

775 lines
19 KiB
C

/*
* Copyright (c) 1988, 1993
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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 defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)getpwent.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#include <stdio.h>
#include <sys/param.h>
#include <fcntl.h>
#include <db.h>
#include <syslog.h>
#include <pwd.h>
#include <utmp.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <grp.h>
static struct passwd _pw_passwd; /* password structure */
static DB *_pw_db; /* password database */
static int _pw_keynum; /* key counter */
static int _pw_stayopen; /* keep fd's open */
#ifdef YP
#include <rpc/rpc.h>
#include <rpcsvc/yp_prot.h>
#include <rpcsvc/ypclnt.h>
struct _namelist {
char *name;
struct _namelist *next;
};
static struct passwd _pw_copy;
struct _pw_cache {
struct passwd pw_entry;
struct _namelist *namelist;
struct _pw_cache *next;
};
static int _pluscnt, _minuscnt;
static struct _pw_cache *_plushead = NULL, *_minushead = NULL;
static void _createcaches(), _freecaches();
static int _scancaches(char *);
static int _yp_enabled; /* set true when yp enabled */
static int _pw_stepping_yp; /* set true when stepping thru map */
static int _yp_done;
static int _gotmaster;
static char *_pw_yp_domain;
static int _havemaster(char *);
static int _getyppass(struct passwd *, const char *, const char *);
static int _nextyppass(struct passwd *);
#endif
static int __hashpw(), __initdb();
struct passwd *
getpwent()
{
DBT key;
char bf[sizeof(_pw_keynum) + 1];
int rv;
if (!_pw_db && !__initdb())
return((struct passwd *)NULL);
#ifdef YP
if(_pw_stepping_yp) {
_pw_passwd = _pw_copy;
if (_nextyppass(&_pw_passwd))
return (&_pw_passwd);
else
_yp_done = 1;
}
#endif
tryagain:
++_pw_keynum;
bf[0] = _PW_KEYBYNUM;
bcopy((char *)&_pw_keynum, bf + 1, sizeof(_pw_keynum));
key.data = (u_char *)bf;
key.size = sizeof(_pw_keynum) + 1;
rv = __hashpw(&key);
if(!rv) return (struct passwd *)NULL;
#ifdef YP
if(_pw_passwd.pw_name[0] == '+' || _pw_passwd.pw_name[0] == '-') {
_pw_copy = _pw_passwd;
if (_yp_done || !_nextyppass(&_pw_passwd))
goto tryagain;
else
return (&_pw_passwd);
}
#else
/* Ignore YP password file entries when YP is disabled. */
if(_pw_passwd.pw_name[0] == '+' || _pw_passwd.pw_name[0] == '-') {
goto tryagain;
}
#endif
return(&_pw_passwd);
}
struct passwd *
getpwnam(name)
const char *name;
{
DBT key;
int len, rval;
char bf[UT_NAMESIZE + 2];
if (!_pw_db && !__initdb())
return((struct passwd *)NULL);
bf[0] = _PW_KEYBYNAME;
len = strlen(name);
bcopy(name, bf + 1, MIN(len, UT_NAMESIZE));
key.data = (u_char *)bf;
key.size = len + 1;
rval = __hashpw(&key);
#ifdef YP
if (!rval && _yp_enabled)
rval = _getyppass(&_pw_passwd, name, "passwd.byname");
#endif
/*
* Prevent login attempts when YP is not enabled but YP entries
* are in /etc/master.passwd.
*/
if (rval && (_pw_passwd.pw_name[0] == '+'||
_pw_passwd.pw_name[0] == '-')) rval = 0;
endpwent();
return(rval ? &_pw_passwd : (struct passwd *)NULL);
}
struct passwd *
#ifdef __STDC__
getpwuid(uid_t uid)
#else
getpwuid(uid)
int uid;
#endif
{
DBT key;
int keyuid, rval;
char bf[sizeof(keyuid) + 1];
if (!_pw_db && !__initdb())
return((struct passwd *)NULL);
bf[0] = _PW_KEYBYUID;
keyuid = uid;
bcopy(&keyuid, bf + 1, sizeof(keyuid));
key.data = (u_char *)bf;
key.size = sizeof(keyuid) + 1;
rval = __hashpw(&key);
#ifdef YP
if (!rval && _yp_enabled) {
char ypbuf[16]; /* big enough for 32-bit uids and then some */
snprintf(ypbuf, sizeof ypbuf, "%u", (unsigned)uid);
rval = _getyppass(&_pw_passwd, ypbuf, "passwd.byuid");
}
#endif
/*
* Prevent login attempts when YP is not enabled but YP entries
* are in /etc/master.passwd.
*/
if (rval && (_pw_passwd.pw_name[0] == '+'||
_pw_passwd.pw_name[0] == '-')) rval = 0;
endpwent();
return(rval ? &_pw_passwd : (struct passwd *)NULL);
}
int
setpassent(stayopen)
int stayopen;
{
_pw_keynum = 0;
#ifdef YP
_pw_stepping_yp = _yp_done = 0;
#endif
_pw_stayopen = stayopen;
return(1);
}
int
setpwent()
{
_pw_keynum = 0;
#ifdef YP
_pw_stepping_yp = _yp_done = 0;
#endif
_pw_stayopen = 0;
return(1);
}
void
endpwent()
{
_pw_keynum = 0;
#ifdef YP
_pw_stepping_yp = _yp_done = 0;
#endif
if (_pw_db) {
(void)(_pw_db->close)(_pw_db);
_pw_db = (DB *)NULL;
#ifdef YP
_freecaches();
#endif
}
}
static
__initdb()
{
static int warned;
char *p;
p = (geteuid()) ? _PATH_MP_DB : _PATH_SMP_DB;
_pw_db = dbopen(p, O_RDONLY, 0, DB_HASH, NULL);
if (_pw_db) {
#ifdef YP
DBT key, data;
char buf[] = { _PW_KEYYPENABLED };
key.data = buf;
key.size = 1;
if ((_pw_db->get)(_pw_db, &key, &data, 0)) {
_yp_enabled = 0;
} else {
_yp_enabled = (int)*((char *)data.data) - 2;
_createcaches();
/* Don't even bother with this if we aren't root. */
if (!geteuid()) {
if (!_pw_yp_domain)
if (yp_get_default_domain(&_pw_yp_domain))
return(1);
_gotmaster = _havemaster(_pw_yp_domain);
} else _gotmaster = 0;
}
#endif
return(1);
}
if (!warned)
syslog(LOG_ERR, "%s: %m", p);
return(0);
}
static
__hashpw(key)
DBT *key;
{
register char *p, *t;
static u_int max;
static char *line;
DBT data;
if ((_pw_db->get)(_pw_db, key, &data, 0))
return(0);
p = (char *)data.data;
if (data.size > max && !(line = realloc(line, max += 1024)))
return(0);
t = line;
#define EXPAND(e) e = t; while (*t++ = *p++);
EXPAND(_pw_passwd.pw_name);
EXPAND(_pw_passwd.pw_passwd);
bcopy(p, (char *)&_pw_passwd.pw_uid, sizeof(int));
p += sizeof(int);
bcopy(p, (char *)&_pw_passwd.pw_gid, sizeof(int));
p += sizeof(int);
bcopy(p, (char *)&_pw_passwd.pw_change, sizeof(time_t));
p += sizeof(time_t);
EXPAND(_pw_passwd.pw_class);
EXPAND(_pw_passwd.pw_gecos);
EXPAND(_pw_passwd.pw_dir);
EXPAND(_pw_passwd.pw_shell);
bcopy(p, (char *)&_pw_passwd.pw_expire, sizeof(time_t));
p += sizeof(time_t);
bcopy(p, (char *)&_pw_passwd.pw_fields, sizeof _pw_passwd.pw_fields);
p += sizeof _pw_passwd.pw_fields;
return(1);
}
#ifdef YP
/*
* Build special +@netgroup and -@netgroup caches. We also handle ordinary
* +user/-user entries, *and* +@group/-@group entries, which are special
* cases of the +@netgroup/-@netgroup substitutions: if we can't find
* netgroup 'foo', we look for a regular user group called 'foo' and
* match against that instead. The netgroup takes precedence since the
* +group/-group support is basically just a hack to make Justin T. Gibbs
* happy. :) Sorting out all the funny business here lets us have a
* yp_enabled flag with a simple on or off value instead of the somewhat
* bogus setup we had before.
*
* We cache everything here in one shot so that we only have to scan
* each netgroup/group once. The alternative is to use innetgr() inside the
* NIS lookup functions, which would make retrieving the whole password
* database though getpwent() very slow. +user/-user entries are treated
* like @groups/@netgroups with only one member.
*/
static void
_createcaches()
{
DBT key, data;
int i;
char bf[UT_NAMESIZE + 2];
struct _pw_cache *p, *m;
struct _namelist *n, *namehead;
char *user, *host, *domain;
struct group *grp;
/*
* Assume that the database has already been initialized
* but be paranoid and check that YP is in fact enabled.
*/
if (!_yp_enabled)
return;
/*
* For the plus list, we have to store both the linked list of
* names and the +entries from the password database so we can
* do the substitution later if we find a match.
*/
bf[0] = _PW_KEYPLUSCNT;
key.data = (u_char*)bf;
key.size = 1;
if (!(_pw_db->get)(_pw_db, &key, &data, 0)) {
_pluscnt = (int)*((char *)data.data);
for (i = 0; i < _pluscnt; i++) {
bf[0] = _PW_KEYPLUSBYNUM;
bcopy(&i, bf + 1, sizeof(i) + 1);
key.size = (sizeof(i)) + 1;
if (__hashpw(&key)) {
p = (struct _pw_cache *)malloc(sizeof (struct _pw_cache));
if (strlen(_pw_passwd.pw_name) > 2 && _pw_passwd.pw_name[1] == '@') {
setnetgrent(_pw_passwd.pw_name+2);
namehead = NULL;
while(getnetgrent(&host, &user, &domain)) {
n = (struct _namelist *)malloc(sizeof (struct _namelist));
n->name = strdup(user);
n->next = namehead;
namehead = n;
}
/*
* If netgroup 'foo' doesn't exist,
* try group 'foo' instead.
*/
if (namehead == NULL && (grp = getgrnam(_pw_passwd.pw_name+2)) != NULL) {
while(*grp->gr_mem) {
n = (struct _namelist *)malloc(sizeof (struct _namelist));
n->name = strdup(*grp->gr_mem);
n->next = namehead;
namehead = n;
grp->gr_mem++;
}
}
} else {
if (_pw_passwd.pw_name[1] != '@') {
namehead = (struct _namelist *)malloc(sizeof (struct _namelist));
namehead->name = strdup(_pw_passwd.pw_name+1);
namehead->next = NULL;
}
}
p->namelist = namehead;
p->pw_entry.pw_name = strdup(_pw_passwd.pw_name);
p->pw_entry.pw_passwd = strdup(_pw_passwd.pw_passwd);
p->pw_entry.pw_uid = _pw_passwd.pw_uid;
p->pw_entry.pw_gid = _pw_passwd.pw_gid;
p->pw_entry.pw_expire = _pw_passwd.pw_expire;
p->pw_entry.pw_change = _pw_passwd.pw_change;
p->pw_entry.pw_class = strdup(_pw_passwd.pw_class);
p->pw_entry.pw_gecos = strdup(_pw_passwd.pw_gecos);
p->pw_entry.pw_dir = strdup(_pw_passwd.pw_dir);
p->pw_entry.pw_shell = strdup(_pw_passwd.pw_shell);
p->pw_entry.pw_fields = _pw_passwd.pw_fields;
p->next = _plushead;
_plushead = p;
}
}
}
/*
* All we need for the minuslist is the usernames.
* The actual -entries data can be ignored since no substitution
* will be done: anybody on the minus list is treated like a
* non-person.
*/
bf[0] = _PW_KEYMINUSCNT;
key.data = (u_char*)bf;
key.size = 1;
if (!(_pw_db->get)(_pw_db, &key, &data, 0)) {
_minuscnt = (int)*((char *)data.data);
for (i = _minuscnt; i > -1; i--) {
bf[0] = _PW_KEYMINUSBYNUM;
bcopy(&i, bf + 1, sizeof(i) + 1);
key.size = (sizeof(i)) + 1;
if (__hashpw(&key)) {
m = (struct _pw_cache *)malloc(sizeof (struct _pw_cache));
if (strlen (_pw_passwd.pw_name) > 2 && _pw_passwd.pw_name[1] == '@') {
namehead = NULL;
setnetgrent(_pw_passwd.pw_name+2);
while(getnetgrent(&host, &user, &domain)) {
n = (struct _namelist *)malloc(sizeof (struct _namelist));
n->name = strdup(user);
n->next = namehead;
namehead = n;
}
/*
* If netgroup 'foo' doesn't exist,
* try group 'foo' instead.
*/
if (namehead == NULL && (grp = getgrnam(_pw_passwd.pw_name+2)) != NULL) {
while(*grp->gr_mem) {
n = (struct _namelist *)malloc(sizeof (struct _namelist));
n->name = strdup(*grp->gr_mem);
n->next = namehead;
namehead = n;
grp->gr_mem++;
}
}
} else {
if (_pw_passwd.pw_name[1] != '@') {
namehead = (struct _namelist *)malloc(sizeof (struct _namelist));
namehead->name = strdup(_pw_passwd.pw_name+1);
namehead->next = NULL;
}
}
/* Save just the name */
m->pw_entry.pw_name = strdup(_pw_passwd.pw_name);
m->namelist = namehead;
m->next = _minushead;
_minushead = m;
}
}
}
endgrent();
endnetgrent();
}
/*
* Free the +@netgroup/-@netgroup caches. Should be called
* from endpwent(). We have to blow away both the list of
* netgroups and the attached linked lists of usernames.
*/
static void
_freecaches()
{
struct _pw_cache *p, *m;
struct _namelist *n;
while (_plushead) {
while(_plushead->namelist) {
n = _plushead->namelist->next;
free(_plushead->namelist->name);
free(_plushead->namelist);
_plushead->namelist = n;
}
free(_plushead->pw_entry.pw_name);
free(_plushead->pw_entry.pw_passwd);
free(_plushead->pw_entry.pw_class);
free(_plushead->pw_entry.pw_gecos);
free(_plushead->pw_entry.pw_dir);
free(_plushead->pw_entry.pw_shell);
p = _plushead->next;
free(_plushead);
_plushead = p;
}
while(_minushead) {
while(_minushead->namelist) {
n = _minushead->namelist->next;
free(_minushead->namelist->name);
free(_minushead->namelist);
_minushead->namelist = n;
}
m = _minushead->next;
free(_minushead);
_minushead = m;
}
_pluscnt = _minuscnt = 0;
}
static int _scancaches(user)
char *user;
{
register struct _pw_cache *m, *p;
register struct _namelist *n;
if (_minuscnt && _minushead) {
m = _minushead;
while (m) {
n = m->namelist;
while (n) {
if (!strcmp(n->name,user) || *n->name == '\0')
return (1);
n = n->next;
}
m = m->next;
}
}
if (_pluscnt && _plushead) {
p = _plushead;
while (p) {
n = p->namelist;
while (n) {
if (!strcmp(n->name, user) || *n->name == '\0')
bcopy((char *)&p->pw_entry,
(char *)&_pw_passwd, sizeof(p->pw_entry));
n = n->next;
}
p = p->next;
}
}
return(0);
}
static int
_pw_breakout_yp(struct passwd *pw, char *res, int master)
{
char *s, *result;
static char resbuf[YPMAXRECORD+2];
/*
* Be triple, ultra super-duper paranoid: reject entries
* that start with a + or -. yp_mkdb and /var/yp/Makefile
* are _both_ supposed to strip these out, but you never
* know.
*/
if (*res == '+' || *res == '-')
return 0;
/*
* The NIS protocol definition limits the size of an NIS
* record to YPMAXRECORD bytes. We need to do a copy to
* a static buffer here since the memory pointed to by
* res will be free()ed when this function returns.
*/
strncpy((char *)&resbuf, res, YPMAXRECORD);
result = (char *)&resbuf;
/*
* XXX Sanity check: make sure all fields are valid (no NULLs).
* If we find a badly formatted entry, we punt.
*/
if ((s = strsep(&result, ":")) == NULL) return 0; /* name */
/*
* We don't care what pw_fields says: we _always_ want the
* username returned to us by NIS.
*/
pw->pw_name = s;
pw->pw_fields |= _PWF_NAME;
if ((s = strsep(&result, ":")) == NULL) return 0; /* password */
if(!(pw->pw_fields & _PWF_PASSWD)) {
pw->pw_passwd = s;
pw->pw_fields |= _PWF_PASSWD;
}
if ((s = strsep(&result, ":")) == NULL) return 0; /* uid */
if(!(pw->pw_fields & _PWF_UID)) {
pw->pw_uid = atoi(s);
pw->pw_fields |= _PWF_UID;
}
if ((s = strsep(&result, ":")) == NULL) return 0; /* gid */
if(!(pw->pw_fields & _PWF_GID)) {
pw->pw_gid = atoi(s);
pw->pw_fields |= _PWF_GID;
}
if (master) {
if ((s = strsep(&result, ":")) == NULL) return 0; /* class */
if(!(pw->pw_fields & _PWF_CLASS)) {
pw->pw_class = s;
pw->pw_fields |= _PWF_CLASS;
}
if ((s = strsep(&result, ":")) == NULL) return 0; /* change */
if(!(pw->pw_fields & _PWF_CHANGE)) {
pw->pw_change = atol(s);
pw->pw_fields |= _PWF_CHANGE;
}
if ((s = strsep(&result, ":")) == NULL) return 0; /* expire */
if(!(pw->pw_fields & _PWF_EXPIRE)) {
pw->pw_expire = atol(s);
pw->pw_fields |= _PWF_EXPIRE;
}
}
if ((s = strsep(&result, ":")) == NULL) return 0; /* gecos */
if(!(pw->pw_fields & _PWF_GECOS)) {
pw->pw_gecos = s;
pw->pw_fields |= _PWF_GECOS;
}
if ((s = strsep(&result, ":")) == NULL) return 0; /* dir */
if(!(pw->pw_fields & _PWF_DIR)) {
pw->pw_dir = s;
pw->pw_fields |= _PWF_DIR;
}
if ((s = strsep(&result, ":")) == NULL) return 0; /* shell */
if(!(pw->pw_fields & _PWF_SHELL)) {
pw->pw_shell = s;
pw->pw_fields |= _PWF_SHELL;
}
/* Be consistent. */
if ((s = strchr(pw->pw_shell, '\n'))) *s = '\0';
return 1;
}
static int
_havemaster(char *_pw_yp_domain)
{
int keylen, resultlen;
char *key, *result;
if (yp_first(_pw_yp_domain, "master.passwd.byname",
&key, &keylen, &result, &resultlen)) {
return 0;
}
free(result);
return 1;
}
static int
_getyppass(struct passwd *pw, const char *name, const char *map)
{
char *result, *s;
int resultlen;
int rv;
char mastermap[1024];
if(!_pw_yp_domain) {
if(yp_get_default_domain(&_pw_yp_domain))
return 0;
}
sprintf(mastermap,"%s",map);
if (_gotmaster)
sprintf(mastermap,"master.%s", map);
if(yp_match(_pw_yp_domain, (char *)&mastermap, name, strlen(name),
&result, &resultlen))
return 0;
s = strchr(result, ':');
if (s) {
*s = '\0';
} else {
/* Must be a malformed entry if no colons. */
free(result);
return(0);
}
_pw_passwd.pw_fields = -1; /* Impossible value */
if (_scancaches(result)) {
free(result);
return(0);
}
/* No hits in the plus or minus lists: Bzzt! reject. */
if (_pw_passwd.pw_fields == -1) {
free(result);
return(0);
}
*s = ':'; /* Put back the colon we previously replaced with a NUL. */
rv = _pw_breakout_yp(pw, result, _gotmaster);
free(result);
return(rv);
}
static int
_nextyppass(struct passwd *pw)
{
static char *key;
static int keylen;
char *lastkey, *result, *s;
int resultlen;
int rv;
char *map = "passwd.byname";
if(!_pw_yp_domain) {
if(yp_get_default_domain(&_pw_yp_domain))
return 0;
}
if (_gotmaster)
map = "master.passwd.byname";
if(!_pw_stepping_yp) {
if(key) free(key);
rv = yp_first(_pw_yp_domain, map,
&key, &keylen, &result, &resultlen);
if(rv) {
return 0;
}
_pw_stepping_yp = 1;
goto unpack;
} else {
tryagain:
lastkey = key;
rv = yp_next(_pw_yp_domain, map, key, keylen,
&key, &keylen, &result, &resultlen);
free(lastkey);
unpack:
if(rv) {
_pw_stepping_yp = 0;
return 0;
}
s = strchr(result, ':');
if (s) {
*s = '\0';
} else {
/* Must be a malformed entry if no colon. */
free(result);
goto tryagain;
}
_pw_passwd.pw_fields = -1; /* Impossible value */
if (_scancaches(result)) {
free(result);
goto tryagain;
}
/* No plus or minus hits: Bzzzt! reject. */
if (_pw_passwd.pw_fields == -1) {
free(result);
goto tryagain;
}
*s = ':'; /* Put back colon we previously replaced with a NUL. */
if(s = strchr(result, '\n')) *s = '\0';
if (_pw_breakout_yp(pw, result, _gotmaster)) {
free(result);
return(1);
} else {
free(result);
goto tryagain;
}
}
}
#endif /* YP */