1/*	$NetBSD: pwcache.c,v 1.31 2010/03/23 20:28:59 drochner Exp $	*/
2
3/*-
4 * Copyright (c) 1992 Keith Muller.
5 * Copyright (c) 1992, 1993
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Keith Muller of the University of California, San Diego.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36/*-
37 * Copyright (c) 2002 The NetBSD Foundation, Inc.
38 * All rights reserved.
39 *
40 * Redistribution and use in source and binary forms, with or without
41 * modification, are permitted provided that the following conditions
42 * are met:
43 * 1. Redistributions of source code must retain the above copyright
44 *    notice, this list of conditions and the following disclaimer.
45 * 2. Redistributions in binary form must reproduce the above copyright
46 *    notice, this list of conditions and the following disclaimer in the
47 *    documentation and/or other materials provided with the distribution.
48 *
49 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
50 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
51 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
52 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
53 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
54 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
55 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
56 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
57 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
58 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
59 * POSSIBILITY OF SUCH DAMAGE.
60 */
61
62#if HAVE_NBTOOL_CONFIG_H
63#include "nbtool_config.h"
64/*
65 * XXX Undefine the renames of these functions so that we don't
66 * XXX rename the versions found in the host's <pwd.h> by mistake!
67 */
68#undef group_from_gid
69#undef user_from_uid
70#endif
71
72#include <sys/cdefs.h>
73#if defined(LIBC_SCCS) && !defined(lint)
74#if 0
75static char sccsid[] = "@(#)cache.c	8.1 (Berkeley) 5/31/93";
76#else
77__RCSID("$NetBSD: pwcache.c,v 1.31 2010/03/23 20:28:59 drochner Exp $");
78#endif
79#endif /* LIBC_SCCS and not lint */
80__FBSDID("$FreeBSD$");
81
82#include "namespace.h"
83
84#include <sys/types.h>
85#include <sys/param.h>
86
87#include <assert.h>
88#include <grp.h>
89#include <pwd.h>
90#include <stdio.h>
91#include <stdlib.h>
92#include <string.h>
93#include <unistd.h>
94
95#define	_DIAGASSERT(x)	assert((x))
96
97#if HAVE_NBTOOL_CONFIG_H
98/* XXX Now, re-apply the renaming that we undid above. */
99#define	group_from_gid	__nbcompat_group_from_gid
100#define	user_from_uid	__nbcompat_user_from_uid
101#endif
102
103#ifdef __weak_alias
104__weak_alias(user_from_uid,_user_from_uid)
105__weak_alias(group_from_gid,_group_from_gid)
106__weak_alias(pwcache_groupdb,_pwcache_groupdb)
107#endif
108
109#if !HAVE_PWCACHE_USERDB || HAVE_NBTOOL_CONFIG_H
110#include "pwcache.h"
111
112/*
113 * routines that control user, group, uid and gid caches (for the archive
114 * member print routine).
115 * IMPORTANT:
116 * these routines cache BOTH hits and misses, a major performance improvement
117 */
118
119/*
120 * function pointers to various name lookup routines.
121 * these may be changed as necessary.
122 */
123static	int		(*_pwcache_setgroupent)(int)		= setgroupent;
124static	void		(*_pwcache_endgrent)(void)		= endgrent;
125static	struct group *	(*_pwcache_getgrnam)(const char *)	= getgrnam;
126static	struct group *	(*_pwcache_getgrgid)(gid_t)		= getgrgid;
127static	int		(*_pwcache_setpassent)(int)		= setpassent;
128static	void		(*_pwcache_endpwent)(void)		= endpwent;
129static	struct passwd *	(*_pwcache_getpwnam)(const char *)	= getpwnam;
130static	struct passwd *	(*_pwcache_getpwuid)(uid_t)		= getpwuid;
131
132/*
133 * internal state
134 */
135static	int	pwopn;		/* is password file open */
136static	int	gropn;		/* is group file open */
137static	UIDC	**uidtb;	/* uid to name cache */
138static	GIDC	**gidtb;	/* gid to name cache */
139static	UIDC	**usrtb;	/* user name to uid cache */
140static	GIDC	**grptb;	/* group name to gid cache */
141
142static	int	uidtb_fail;	/* uidtb_start() failed ? */
143static	int	gidtb_fail;	/* gidtb_start() failed ? */
144static	int	usrtb_fail;	/* usrtb_start() failed ? */
145static	int	grptb_fail;	/* grptb_start() failed ? */
146
147
148static	u_int	st_hash(const char *, size_t, int);
149static	int	uidtb_start(void);
150static	int	gidtb_start(void);
151static	int	usrtb_start(void);
152static	int	grptb_start(void);
153
154
155static u_int
156st_hash(const char *name, size_t len, int tabsz)
157{
158	u_int key = 0;
159
160	_DIAGASSERT(name != NULL);
161
162	while (len--) {
163		key += *name++;
164		key = (key << 8) | (key >> 24);
165	}
166
167	return (key % tabsz);
168}
169
170/*
171 * uidtb_start
172 *	creates an an empty uidtb
173 * Return:
174 *	0 if ok, -1 otherwise
175 */
176static int
177uidtb_start(void)
178{
179
180	if (uidtb != NULL)
181		return (0);
182	if (uidtb_fail)
183		return (-1);
184	if ((uidtb = (UIDC **)calloc(UID_SZ, sizeof(UIDC *))) == NULL) {
185		++uidtb_fail;
186		return (-1);
187	}
188	return (0);
189}
190
191/*
192 * gidtb_start
193 *	creates an an empty gidtb
194 * Return:
195 *	0 if ok, -1 otherwise
196 */
197static int
198gidtb_start(void)
199{
200
201	if (gidtb != NULL)
202		return (0);
203	if (gidtb_fail)
204		return (-1);
205	if ((gidtb = (GIDC **)calloc(GID_SZ, sizeof(GIDC *))) == NULL) {
206		++gidtb_fail;
207		return (-1);
208	}
209	return (0);
210}
211
212/*
213 * usrtb_start
214 *	creates an an empty usrtb
215 * Return:
216 *	0 if ok, -1 otherwise
217 */
218static int
219usrtb_start(void)
220{
221
222	if (usrtb != NULL)
223		return (0);
224	if (usrtb_fail)
225		return (-1);
226	if ((usrtb = (UIDC **)calloc(UNM_SZ, sizeof(UIDC *))) == NULL) {
227		++usrtb_fail;
228		return (-1);
229	}
230	return (0);
231}
232
233/*
234 * grptb_start
235 *	creates an an empty grptb
236 * Return:
237 *	0 if ok, -1 otherwise
238 */
239static int
240grptb_start(void)
241{
242
243	if (grptb != NULL)
244		return (0);
245	if (grptb_fail)
246		return (-1);
247	if ((grptb = (GIDC **)calloc(GNM_SZ, sizeof(GIDC *))) == NULL) {
248		++grptb_fail;
249		return (-1);
250	}
251	return (0);
252}
253
254/*
255 * user_from_uid()
256 *	caches the name (if any) for the uid. If noname clear, we always
257 *	return the stored name (if valid or invalid match).
258 *	We use a simple hash table.
259 * Return
260 *	Pointer to stored name (or a empty string)
261 */
262const char *
263user_from_uid(uid_t uid, int noname)
264{
265	struct passwd *pw;
266	UIDC *ptr, **pptr;
267
268	if ((uidtb == NULL) && (uidtb_start() < 0))
269		return (NULL);
270
271	/*
272	 * see if we have this uid cached
273	 */
274	pptr = uidtb + (uid % UID_SZ);
275	ptr = *pptr;
276
277	if ((ptr != NULL) && (ptr->valid > 0) && (ptr->uid == uid)) {
278		/*
279		 * have an entry for this uid
280		 */
281		if (!noname || (ptr->valid == VALID))
282			return (ptr->name);
283		return (NULL);
284	}
285
286	/*
287	 * No entry for this uid, we will add it
288	 */
289	if (!pwopn) {
290		if (_pwcache_setpassent != NULL)
291			(*_pwcache_setpassent)(1);
292		++pwopn;
293	}
294
295	if (ptr == NULL)
296		*pptr = ptr = (UIDC *)malloc(sizeof(UIDC));
297
298	if ((pw = (*_pwcache_getpwuid)(uid)) == NULL) {
299		/*
300		 * no match for this uid in the local password file
301		 * a string that is the uid in numeric format
302		 */
303		if (ptr == NULL)
304			return (NULL);
305		ptr->uid = uid;
306		(void)snprintf(ptr->name, UNMLEN, "%lu", (long) uid);
307		ptr->valid = INVALID;
308		if (noname)
309			return (NULL);
310	} else {
311		/*
312		 * there is an entry for this uid in the password file
313		 */
314		if (ptr == NULL)
315			return (pw->pw_name);
316		ptr->uid = uid;
317		(void)strlcpy(ptr->name, pw->pw_name, UNMLEN);
318		ptr->valid = VALID;
319	}
320	return (ptr->name);
321}
322
323/*
324 * group_from_gid()
325 *	caches the name (if any) for the gid. If noname clear, we always
326 *	return the stored name (if valid or invalid match).
327 *	We use a simple hash table.
328 * Return
329 *	Pointer to stored name (or a empty string)
330 */
331const char *
332group_from_gid(gid_t gid, int noname)
333{
334	struct group *gr;
335	GIDC *ptr, **pptr;
336
337	if ((gidtb == NULL) && (gidtb_start() < 0))
338		return (NULL);
339
340	/*
341	 * see if we have this gid cached
342	 */
343	pptr = gidtb + (gid % GID_SZ);
344	ptr = *pptr;
345
346	if ((ptr != NULL) && (ptr->valid > 0) && (ptr->gid == gid)) {
347		/*
348		 * have an entry for this gid
349		 */
350		if (!noname || (ptr->valid == VALID))
351			return (ptr->name);
352		return (NULL);
353	}
354
355	/*
356	 * No entry for this gid, we will add it
357	 */
358	if (!gropn) {
359		if (_pwcache_setgroupent != NULL)
360			(*_pwcache_setgroupent)(1);
361		++gropn;
362	}
363
364	if (ptr == NULL)
365		*pptr = ptr = (GIDC *)malloc(sizeof(GIDC));
366
367	if ((gr = (*_pwcache_getgrgid)(gid)) == NULL) {
368		/*
369		 * no match for this gid in the local group file, put in
370		 * a string that is the gid in numberic format
371		 */
372		if (ptr == NULL)
373			return (NULL);
374		ptr->gid = gid;
375		(void)snprintf(ptr->name, GNMLEN, "%lu", (long) gid);
376		ptr->valid = INVALID;
377		if (noname)
378			return (NULL);
379	} else {
380		/*
381		 * there is an entry for this group in the group file
382		 */
383		if (ptr == NULL)
384			return (gr->gr_name);
385		ptr->gid = gid;
386		(void)strlcpy(ptr->name, gr->gr_name, GNMLEN);
387		ptr->valid = VALID;
388	}
389	return (ptr->name);
390}
391
392/*
393 * uid_from_user()
394 *	caches the uid for a given user name. We use a simple hash table.
395 * Return
396 *	the uid (if any) for a user name, or a -1 if no match can be found
397 */
398int
399uid_from_user(const char *name, uid_t *uid)
400{
401	struct passwd *pw;
402	UIDC *ptr, **pptr;
403	size_t namelen;
404
405	/*
406	 * return -1 for mangled names
407	 */
408	if (name == NULL || ((namelen = strlen(name)) == 0))
409		return (-1);
410	if ((usrtb == NULL) && (usrtb_start() < 0))
411		return (-1);
412
413	/*
414	 * look up in hash table, if found and valid return the uid,
415	 * if found and invalid, return a -1
416	 */
417	pptr = usrtb + st_hash(name, namelen, UNM_SZ);
418	ptr = *pptr;
419
420	if ((ptr != NULL) && (ptr->valid > 0) && !strcmp(name, ptr->name)) {
421		if (ptr->valid == INVALID)
422			return (-1);
423		*uid = ptr->uid;
424		return (0);
425	}
426
427	if (!pwopn) {
428		if (_pwcache_setpassent != NULL)
429			(*_pwcache_setpassent)(1);
430		++pwopn;
431	}
432
433	if (ptr == NULL)
434		*pptr = ptr = (UIDC *)malloc(sizeof(UIDC));
435
436	/*
437	 * no match, look it up, if no match store it as an invalid entry,
438	 * or store the matching uid
439	 */
440	if (ptr == NULL) {
441		if ((pw = (*_pwcache_getpwnam)(name)) == NULL)
442			return (-1);
443		*uid = pw->pw_uid;
444		return (0);
445	}
446	(void)strlcpy(ptr->name, name, UNMLEN);
447	if ((pw = (*_pwcache_getpwnam)(name)) == NULL) {
448		ptr->valid = INVALID;
449		return (-1);
450	}
451	ptr->valid = VALID;
452	*uid = ptr->uid = pw->pw_uid;
453	return (0);
454}
455
456/*
457 * gid_from_group()
458 *	caches the gid for a given group name. We use a simple hash table.
459 * Return
460 *	the gid (if any) for a group name, or a -1 if no match can be found
461 */
462int
463gid_from_group(const char *name, gid_t *gid)
464{
465	struct group *gr;
466	GIDC *ptr, **pptr;
467	size_t namelen;
468
469	/*
470	 * return -1 for mangled names
471	 */
472	if (name == NULL || ((namelen = strlen(name)) == 0))
473		return (-1);
474	if ((grptb == NULL) && (grptb_start() < 0))
475		return (-1);
476
477	/*
478	 * look up in hash table, if found and valid return the uid,
479	 * if found and invalid, return a -1
480	 */
481	pptr = grptb + st_hash(name, namelen, GID_SZ);
482	ptr = *pptr;
483
484	if ((ptr != NULL) && (ptr->valid > 0) && !strcmp(name, ptr->name)) {
485		if (ptr->valid == INVALID)
486			return (-1);
487		*gid = ptr->gid;
488		return (0);
489	}
490
491	if (!gropn) {
492		if (_pwcache_setgroupent != NULL)
493			(*_pwcache_setgroupent)(1);
494		++gropn;
495	}
496
497	if (ptr == NULL)
498		*pptr = ptr = (GIDC *)malloc(sizeof(GIDC));
499
500	/*
501	 * no match, look it up, if no match store it as an invalid entry,
502	 * or store the matching gid
503	 */
504	if (ptr == NULL) {
505		if ((gr = (*_pwcache_getgrnam)(name)) == NULL)
506			return (-1);
507		*gid = gr->gr_gid;
508		return (0);
509	}
510
511	(void)strlcpy(ptr->name, name, GNMLEN);
512	if ((gr = (*_pwcache_getgrnam)(name)) == NULL) {
513		ptr->valid = INVALID;
514		return (-1);
515	}
516	ptr->valid = VALID;
517	*gid = ptr->gid = gr->gr_gid;
518	return (0);
519}
520
521#define FLUSHTB(arr, len, fail)				\
522	do {						\
523		if (arr != NULL) {			\
524			for (i = 0; i < len; i++)	\
525				if (arr[i] != NULL)	\
526					free(arr[i]);	\
527			arr = NULL;			\
528		}					\
529		fail = 0;				\
530	} while (/* CONSTCOND */0);
531
532int
533pwcache_userdb(
534	int		(*a_setpassent)(int),
535	void		(*a_endpwent)(void),
536	struct passwd *	(*a_getpwnam)(const char *),
537	struct passwd *	(*a_getpwuid)(uid_t))
538{
539	int i;
540
541		/* a_setpassent and a_endpwent may be NULL */
542	if (a_getpwnam == NULL || a_getpwuid == NULL)
543		return (-1);
544
545	if (_pwcache_endpwent != NULL)
546		(*_pwcache_endpwent)();
547	FLUSHTB(uidtb, UID_SZ, uidtb_fail);
548	FLUSHTB(usrtb, UNM_SZ, usrtb_fail);
549	pwopn = 0;
550	_pwcache_setpassent = a_setpassent;
551	_pwcache_endpwent = a_endpwent;
552	_pwcache_getpwnam = a_getpwnam;
553	_pwcache_getpwuid = a_getpwuid;
554
555	return (0);
556}
557
558int
559pwcache_groupdb(
560	int		(*a_setgroupent)(int),
561	void		(*a_endgrent)(void),
562	struct group *	(*a_getgrnam)(const char *),
563	struct group *	(*a_getgrgid)(gid_t))
564{
565	int i;
566
567		/* a_setgroupent and a_endgrent may be NULL */
568	if (a_getgrnam == NULL || a_getgrgid == NULL)
569		return (-1);
570
571	if (_pwcache_endgrent != NULL)
572		(*_pwcache_endgrent)();
573	FLUSHTB(gidtb, GID_SZ, gidtb_fail);
574	FLUSHTB(grptb, GNM_SZ, grptb_fail);
575	gropn = 0;
576	_pwcache_setgroupent = a_setgroupent;
577	_pwcache_endgrent = a_endgrent;
578	_pwcache_getgrnam = a_getgrnam;
579	_pwcache_getgrgid = a_getgrgid;
580
581	return (0);
582}
583
584
585#ifdef TEST_PWCACHE
586
587struct passwd *
588test_getpwnam(const char *name)
589{
590	static struct passwd foo;
591
592	memset(&foo, 0, sizeof(foo));
593	if (strcmp(name, "toor") == 0) {
594		foo.pw_uid = 666;
595		return &foo;
596	}
597	return (getpwnam(name));
598}
599
600int
601main(int argc, char *argv[])
602{
603	uid_t	u;
604	int	r, i;
605
606	printf("pass 1 (default userdb)\n");
607	for (i = 1; i < argc; i++) {
608		printf("i: %d, pwopn %d usrtb_fail %d usrtb %p\n",
609		    i, pwopn, usrtb_fail, usrtb);
610		r = uid_from_user(argv[i], &u);
611		if (r == -1)
612			printf("  uid_from_user %s: failed\n", argv[i]);
613		else
614			printf("  uid_from_user %s: %d\n", argv[i], u);
615	}
616	printf("pass 1 finish: pwopn %d usrtb_fail %d usrtb %p\n",
617		    pwopn, usrtb_fail, usrtb);
618
619	puts("");
620	printf("pass 2 (replacement userdb)\n");
621	printf("pwcache_userdb returned %d\n",
622	    pwcache_userdb(setpassent, test_getpwnam, getpwuid));
623	printf("pwopn %d usrtb_fail %d usrtb %p\n", pwopn, usrtb_fail, usrtb);
624
625	for (i = 1; i < argc; i++) {
626		printf("i: %d, pwopn %d usrtb_fail %d usrtb %p\n",
627		    i, pwopn, usrtb_fail, usrtb);
628		u = -1;
629		r = uid_from_user(argv[i], &u);
630		if (r == -1)
631			printf("  uid_from_user %s: failed\n", argv[i]);
632		else
633			printf("  uid_from_user %s: %d\n", argv[i], u);
634	}
635	printf("pass 2 finish: pwopn %d usrtb_fail %d usrtb %p\n",
636		    pwopn, usrtb_fail, usrtb);
637
638	puts("");
639	printf("pass 3 (null pointers)\n");
640	printf("pwcache_userdb returned %d\n",
641	    pwcache_userdb(NULL, NULL, NULL));
642
643	return (0);
644}
645#endif	/* TEST_PWCACHE */
646#endif	/* !HAVE_PWCACHE_USERDB */
647