/* $NetBSD: pwcache.c,v 1.34 2022/04/19 20:32:15 rillig Exp $ */
/*-
* Copyright (c) 1992 Keith Muller.
* Copyright (c) 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Keith Muller of the University of California, San Diego.
*
* 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.
*/
/*-
* Copyright (c) 2002 The NetBSD Foundation, Inc.
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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 HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
/*
* XXX Undefine the renames of these functions so that we don't
* XXX rename the versions found in the host's <pwd.h> by mistake!
*/
#undef group_from_gid
#undef user_from_uid
#endif
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)cache.c 8.1 (Berkeley) 5/31/93";
#else
__RCSID("$NetBSD: pwcache.c,v 1.34 2022/04/19 20:32:15 rillig Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
#include <sys/types.h>
#include <sys/param.h>
#include <assert.h>
#include <grp.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#if HAVE_NBTOOL_CONFIG_H
/* XXX Now, re-apply the renaming that we undid above. */
#define group_from_gid __nbcompat_group_from_gid
#define user_from_uid __nbcompat_user_from_uid
#endif
#ifdef __weak_alias
__weak_alias(user_from_uid,_user_from_uid)
__weak_alias(group_from_gid,_group_from_gid)
__weak_alias(pwcache_groupdb,_pwcache_groupdb)
#endif
#if !HAVE_PWCACHE_USERDB || HAVE_NBTOOL_CONFIG_H
#include "pwcache.h"
/*
* routines that control user, group, uid and gid caches (for the archive
* member print routine).
* IMPORTANT:
* these routines cache BOTH hits and misses, a major performance improvement
*/
/*
* function pointers to various name lookup routines.
* these may be changed as necessary.
*/
static int (*_pwcache_setgroupent)(int) = setgroupent;
static void (*_pwcache_endgrent)(void) = endgrent;
static struct group * (*_pwcache_getgrnam)(const char *) = getgrnam;
static struct group * (*_pwcache_getgrgid)(gid_t) = getgrgid;
static int (*_pwcache_setpassent)(int) = setpassent;
static void (*_pwcache_endpwent)(void) = endpwent;
static struct passwd * (*_pwcache_getpwnam)(const char *) = getpwnam;
static struct passwd * (*_pwcache_getpwuid)(uid_t) = getpwuid;
/*
* internal state
*/
static int pwopn; /* is password file open */
static int gropn; /* is group file open */
static UIDC **uidtb; /* uid to name cache */
static GIDC **gidtb; /* gid to name cache */
static UIDC **usrtb; /* user name to uid cache */
static GIDC **grptb; /* group name to gid cache */
static int uidtb_fail; /* uidtb_start() failed ? */
static int gidtb_fail; /* gidtb_start() failed ? */
static int usrtb_fail; /* usrtb_start() failed ? */
static int grptb_fail; /* grptb_start() failed ? */
static u_int st_hash(const char *, size_t, int);
static int uidtb_start(void);
static int gidtb_start(void);
static int usrtb_start(void);
static int grptb_start(void);
static u_int
st_hash(const char *name, size_t len, int tabsz)
{
u_int key = 0;
_DIAGASSERT(name != NULL);
while (len--) {
key += *name++;
key = (key << 8) | (key >> 24);
}
return (key % tabsz);
}
/*
* uidtb_start
* creates an empty uidtb
* Return:
* 0 if ok, -1 otherwise
*/
static int
uidtb_start(void)
{
if (uidtb != NULL)
return (0);
if (uidtb_fail)
return (-1);
if ((uidtb = (UIDC **)calloc(UID_SZ, sizeof(UIDC *))) == NULL) {
++uidtb_fail;
return (-1);
}
return (0);
}
/*
* gidtb_start
* creates an empty gidtb
* Return:
* 0 if ok, -1 otherwise
*/
static int
gidtb_start(void)
{
if (gidtb != NULL)
return (0);
if (gidtb_fail)
return (-1);
if ((gidtb = (GIDC **)calloc(GID_SZ, sizeof(GIDC *))) == NULL) {
++gidtb_fail;
return (-1);
}
return (0);
}
/*
* usrtb_start
* creates an empty usrtb
* Return:
* 0 if ok, -1 otherwise
*/
static int
usrtb_start(void)
{
if (usrtb != NULL)
return (0);
if (usrtb_fail)
return (-1);
if ((usrtb = (UIDC **)calloc(UNM_SZ, sizeof(UIDC *))) == NULL) {
++usrtb_fail;
return (-1);
}
return (0);
}
/*
* grptb_start
* creates an empty grptb
* Return:
* 0 if ok, -1 otherwise
*/
static int
grptb_start(void)
{
if (grptb != NULL)
return (0);
if (grptb_fail)
return (-1);
if ((grptb = (GIDC **)calloc(GNM_SZ, sizeof(GIDC *))) == NULL) {
++grptb_fail;
return (-1);
}
return (0);
}
/*
* user_from_uid()
* caches the name (if any) for the uid. If noname clear, we always
* return the stored name (if valid or invalid match).
* We use a simple hash table.
* Return
* Pointer to stored name (or a empty string)
*/
const char *
user_from_uid(uid_t uid, int noname)
{
struct passwd *pw;
UIDC *ptr, **pptr;
if ((uidtb == NULL) && (uidtb_start() < 0))
return (NULL);
/*
* see if we have this uid cached
*/
pptr = uidtb + (uid % UID_SZ);
ptr = *pptr;
if ((ptr != NULL) && (ptr->valid > 0) && (ptr->uid == uid)) {
/*
* have an entry for this uid
*/
if (!noname || (ptr->valid == VALID))
return (ptr->name);
return (NULL);
}
/*
* No entry for this uid, we will add it
*/
if (!pwopn) {
if (_pwcache_setpassent != NULL)
(*_pwcache_setpassent)(1);
++pwopn;
}
if (ptr == NULL)
*pptr = ptr = (UIDC *)malloc(sizeof(UIDC));
if ((pw = (*_pwcache_getpwuid)(uid)) == NULL) {
/*
* no match for this uid in the local password file
* a string that is the uid in numeric format
*/
if (ptr == NULL)
return (NULL);
ptr->uid = uid;
(void)snprintf(ptr->name, UNMLEN, "%lu", (long) uid);
ptr->valid = INVALID;
if (noname)
return (NULL);
} else {
/*
* there is an entry for this uid in the password file
*/
if (ptr == NULL)
return (pw->pw_name);
ptr->uid = uid;
(void)strlcpy(ptr->name, pw->pw_name, UNMLEN);
ptr->valid = VALID;
}
return (ptr->name);
}
/*
* group_from_gid()
* caches the name (if any) for the gid. If noname clear, we always
* return the stored name (if valid or invalid match).
* We use a simple hash table.
* Return
* Pointer to stored name (or a empty string)
*/
const char *
group_from_gid(gid_t gid, int noname)
{
struct group *gr;
GIDC *ptr, **pptr;
if ((gidtb == NULL) && (gidtb_start() < 0))
return (NULL);
/*
* see if we have this gid cached
*/
pptr = gidtb + (gid % GID_SZ);
ptr = *pptr;
if ((ptr != NULL) && (ptr->valid > 0) && (ptr->gid == gid)) {
/*
* have an entry for this gid
*/
if (!noname || (ptr->valid == VALID))
return (ptr->name);
return (NULL);
}
/*
* No entry for this gid, we will add it
*/
if (!gropn) {
if (_pwcache_setgroupent != NULL)
(*_pwcache_setgroupent)(1);
++gropn;
}
if (ptr == NULL)
*pptr = ptr = (GIDC *)malloc(sizeof(GIDC));
if ((gr = (*_pwcache_getgrgid)(gid)) == NULL) {
/*
* no match for this gid in the local group file, put in
* a string that is the gid in numeric format
*/
if (ptr == NULL)
return (NULL);
ptr->gid = gid;
(void)snprintf(ptr->name, GNMLEN, "%lu", (long) gid);
ptr->valid = INVALID;
if (noname)
return (NULL);
} else {
/*
* there is an entry for this group in the group file
*/
if (ptr == NULL)
return (gr->gr_name);
ptr->gid = gid;
(void)strlcpy(ptr->name, gr->gr_name, GNMLEN);
ptr->valid = VALID;
}
return (ptr->name);
}
/*
* uid_from_user()
* caches the uid for a given user name. We use a simple hash table.
* Return
* the uid (if any) for a user name, or a -1 if no match can be found
*/
int
uid_from_user(const char *name, uid_t *uid)
{
struct passwd *pw;
UIDC *ptr, **pptr;
size_t namelen;
/*
* return -1 for mangled names
*/
if (name == NULL || ((namelen = strlen(name)) == 0))
return (-1);
if ((usrtb == NULL) && (usrtb_start() < 0))
return (-1);
/*
* look up in hash table, if found and valid return the uid,
* if found and invalid, return a -1
*/
pptr = usrtb + st_hash(name, namelen, UNM_SZ);
ptr = *pptr;
if ((ptr != NULL) && (ptr->valid > 0) && !strcmp(name, ptr->name)) {
if (ptr->valid == INVALID)
return (-1);
*uid = ptr->uid;
return (0);
}
if (!pwopn) {
if (_pwcache_setpassent != NULL)
(*_pwcache_setpassent)(1);
++pwopn;
}
if (ptr == NULL)
*pptr = ptr = (UIDC *)malloc(sizeof(UIDC));
/*
* no match, look it up, if no match store it as an invalid entry,
* or store the matching uid
*/
if (ptr == NULL) {
if ((pw = (*_pwcache_getpwnam)(name)) == NULL)
return (-1);
*uid = pw->pw_uid;
return (0);
}
(void)strlcpy(ptr->name, name, UNMLEN);
if ((pw = (*_pwcache_getpwnam)(name)) == NULL) {
ptr->valid = INVALID;
return (-1);
}
ptr->valid = VALID;
*uid = ptr->uid = pw->pw_uid;
return (0);
}
/*
* gid_from_group()
* caches the gid for a given group name. We use a simple hash table.
* Return
* the gid (if any) for a group name, or a -1 if no match can be found
*/
int
gid_from_group(const char *name, gid_t *gid)
{
struct group *gr;
GIDC *ptr, **pptr;
size_t namelen;
/*
* return -1 for mangled names
*/
if (name == NULL || ((namelen = strlen(name)) == 0))
return (-1);
if ((grptb == NULL) && (grptb_start() < 0))
return (-1);
/*
* look up in hash table, if found and valid return the uid,
* if found and invalid, return a -1
*/
pptr = grptb + st_hash(name, namelen, GID_SZ);
ptr = *pptr;
if ((ptr != NULL) && (ptr->valid > 0) && !strcmp(name, ptr->name)) {
if (ptr->valid == INVALID)
return (-1);
*gid = ptr->gid;
return (0);
}
if (!gropn) {
if (_pwcache_setgroupent != NULL)
(*_pwcache_setgroupent)(1);
++gropn;
}
if (ptr == NULL)
*pptr = ptr = (GIDC *)malloc(sizeof(GIDC));
/*
* no match, look it up, if no match store it as an invalid entry,
* or store the matching gid
*/
if (ptr == NULL) {
if ((gr = (*_pwcache_getgrnam)(name)) == NULL)
return (-1);
*gid = gr->gr_gid;
return (0);
}
(void)strlcpy(ptr->name, name, GNMLEN);
if ((gr = (*_pwcache_getgrnam)(name)) == NULL) {
ptr->valid = INVALID;
return (-1);
}
ptr->valid = VALID;
*gid = ptr->gid = gr->gr_gid;
return (0);
}
#define FLUSHTB(arr, len, fail) \
do { \
if (arr != NULL) { \
for (i = 0; i < len; i++) \
if (arr[i] != NULL) \
free(arr[i]); \
arr = NULL; \
} \
fail = 0; \
} while (0);
int
pwcache_userdb(
int (*a_setpassent)(int),
void (*a_endpwent)(void),
struct passwd * (*a_getpwnam)(const char *),
struct passwd * (*a_getpwuid)(uid_t))
{
int i;
/* a_setpassent and a_endpwent may be NULL */
if (a_getpwnam == NULL || a_getpwuid == NULL)
return (-1);
if (_pwcache_endpwent != NULL)
(*_pwcache_endpwent)();
FLUSHTB(uidtb, UID_SZ, uidtb_fail);
FLUSHTB(usrtb, UNM_SZ, usrtb_fail);
pwopn = 0;
_pwcache_setpassent = a_setpassent;
_pwcache_endpwent = a_endpwent;
_pwcache_getpwnam = a_getpwnam;
_pwcache_getpwuid = a_getpwuid;
return (0);
}
int
pwcache_groupdb(
int (*a_setgroupent)(int),
void (*a_endgrent)(void),
struct group * (*a_getgrnam)(const char *),
struct group * (*a_getgrgid)(gid_t))
{
int i;
/* a_setgroupent and a_endgrent may be NULL */
if (a_getgrnam == NULL || a_getgrgid == NULL)
return (-1);
if (_pwcache_endgrent != NULL)
(*_pwcache_endgrent)();
FLUSHTB(gidtb, GID_SZ, gidtb_fail);
FLUSHTB(grptb, GNM_SZ, grptb_fail);
gropn = 0;
_pwcache_setgroupent = a_setgroupent;
_pwcache_endgrent = a_endgrent;
_pwcache_getgrnam = a_getgrnam;
_pwcache_getgrgid = a_getgrgid;
return (0);
}
#ifdef TEST_PWCACHE
struct passwd *
test_getpwnam(const char *name)
{
static struct passwd foo;
memset(&foo, 0, sizeof(foo));
if (strcmp(name, "toor") == 0) {
foo.pw_uid = 666;
return &foo;
}
return (getpwnam(name));
}
int
main(int argc, char *argv[])
{
uid_t u;
int r, i;
printf("pass 1 (default userdb)\n");
for (i = 1; i < argc; i++) {
printf("i: %d, pwopn %d usrtb_fail %d usrtb %p\n",
i, pwopn, usrtb_fail, usrtb);
r = uid_from_user(argv[i], &u);
if (r == -1)
printf(" uid_from_user %s: failed\n", argv[i]);
else
printf(" uid_from_user %s: %d\n", argv[i], u);
}
printf("pass 1 finish: pwopn %d usrtb_fail %d usrtb %p\n",
pwopn, usrtb_fail, usrtb);
puts("");
printf("pass 2 (replacement userdb)\n");
printf("pwcache_userdb returned %d\n",
pwcache_userdb(setpassent, test_getpwnam, getpwuid));
printf("pwopn %d usrtb_fail %d usrtb %p\n", pwopn, usrtb_fail, usrtb);
for (i = 1; i < argc; i++) {
printf("i: %d, pwopn %d usrtb_fail %d usrtb %p\n",
i, pwopn, usrtb_fail, usrtb);
u = -1;
r = uid_from_user(argv[i], &u);
if (r == -1)
printf(" uid_from_user %s: failed\n", argv[i]);
else
printf(" uid_from_user %s: %d\n", argv[i], u);
}
printf("pass 2 finish: pwopn %d usrtb_fail %d usrtb %p\n",
pwopn, usrtb_fail, usrtb);
puts("");
printf("pass 3 (null pointers)\n");
printf("pwcache_userdb returned %d\n",
pwcache_userdb(NULL, NULL, NULL));
return (0);
}
#endif /* TEST_PWCACHE */
#endif /* !HAVE_PWCACHE_USERDB */