1 /* $NetBSD: pwcache.c,v 1.35 2024/05/12 10:58:58 rillig 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
75 static char sccsid[] = "@(#)cache.c 8.1 (Berkeley) 5/31/93";
76 #else
77 __RCSID("$NetBSD: pwcache.c,v 1.35 2024/05/12 10:58:58 rillig Exp $");
78 #endif
79 #endif /* LIBC_SCCS and not lint */
80
81 #include "namespace.h"
82
83 #include <sys/types.h>
84 #include <sys/param.h>
85
86 #include <assert.h>
87 #include <grp.h>
88 #include <pwd.h>
89 #include <stdio.h>
90 #include <stdlib.h>
91 #include <string.h>
92 #include <unistd.h>
93
94 #if HAVE_NBTOOL_CONFIG_H
95 /* XXX Now, re-apply the renaming that we undid above. */
96 #define group_from_gid __nbcompat_group_from_gid
97 #define user_from_uid __nbcompat_user_from_uid
98 #endif
99
100 #ifdef __weak_alias
101 __weak_alias(user_from_uid,_user_from_uid)
102 __weak_alias(group_from_gid,_group_from_gid)
103 __weak_alias(pwcache_groupdb,_pwcache_groupdb)
104 #endif
105
106 #if !HAVE_PWCACHE_USERDB || HAVE_NBTOOL_CONFIG_H
107 #include "pwcache.h"
108
109 /*
110 * routines that control user, group, uid and gid caches (for the archive
111 * member print routine).
112 * IMPORTANT:
113 * these routines cache BOTH hits and misses, a major performance improvement
114 */
115
116 /*
117 * function pointers to various name lookup routines.
118 * these may be changed as necessary.
119 */
120 static int (*_pwcache_setgroupent)(int) = setgroupent;
121 static void (*_pwcache_endgrent)(void) = endgrent;
122 static struct group * (*_pwcache_getgrnam)(const char *) = getgrnam;
123 static struct group * (*_pwcache_getgrgid)(gid_t) = getgrgid;
124 static int (*_pwcache_setpassent)(int) = setpassent;
125 static void (*_pwcache_endpwent)(void) = endpwent;
126 static struct passwd * (*_pwcache_getpwnam)(const char *) = getpwnam;
127 static struct passwd * (*_pwcache_getpwuid)(uid_t) = getpwuid;
128
129 /*
130 * internal state
131 */
132 static int pwopn; /* is password file open */
133 static int gropn; /* is group file open */
134 static UIDC **uidtb; /* uid to name cache */
135 static GIDC **gidtb; /* gid to name cache */
136 static UIDC **usrtb; /* user name to uid cache */
137 static GIDC **grptb; /* group name to gid cache */
138
139 static int uidtb_fail; /* uidtb_start() failed ? */
140 static int gidtb_fail; /* gidtb_start() failed ? */
141 static int usrtb_fail; /* usrtb_start() failed ? */
142 static int grptb_fail; /* grptb_start() failed ? */
143
144
145 static u_int st_hash(const char *, size_t, int);
146 static int uidtb_start(void);
147 static int gidtb_start(void);
148 static int usrtb_start(void);
149 static int grptb_start(void);
150
151
152 static u_int
st_hash(const char * name,size_t len,int tabsz)153 st_hash(const char *name, size_t len, int tabsz)
154 {
155 u_int key = 0;
156
157 _DIAGASSERT(name != NULL);
158
159 while (len--) {
160 key += *name++;
161 key = (key << 8) | (key >> 24);
162 }
163
164 return (key % tabsz);
165 }
166
167 /*
168 * uidtb_start
169 * creates an empty uidtb
170 * Return:
171 * 0 if ok, -1 otherwise
172 */
173 static int
uidtb_start(void)174 uidtb_start(void)
175 {
176
177 if (uidtb != NULL)
178 return (0);
179 if (uidtb_fail)
180 return (-1);
181 if ((uidtb = (UIDC **)calloc(UID_SZ, sizeof(UIDC *))) == NULL) {
182 ++uidtb_fail;
183 return (-1);
184 }
185 return (0);
186 }
187
188 /*
189 * gidtb_start
190 * creates an empty gidtb
191 * Return:
192 * 0 if ok, -1 otherwise
193 */
194 static int
gidtb_start(void)195 gidtb_start(void)
196 {
197
198 if (gidtb != NULL)
199 return (0);
200 if (gidtb_fail)
201 return (-1);
202 if ((gidtb = (GIDC **)calloc(GID_SZ, sizeof(GIDC *))) == NULL) {
203 ++gidtb_fail;
204 return (-1);
205 }
206 return (0);
207 }
208
209 /*
210 * usrtb_start
211 * creates an empty usrtb
212 * Return:
213 * 0 if ok, -1 otherwise
214 */
215 static int
usrtb_start(void)216 usrtb_start(void)
217 {
218
219 if (usrtb != NULL)
220 return (0);
221 if (usrtb_fail)
222 return (-1);
223 if ((usrtb = (UIDC **)calloc(UNM_SZ, sizeof(UIDC *))) == NULL) {
224 ++usrtb_fail;
225 return (-1);
226 }
227 return (0);
228 }
229
230 /*
231 * grptb_start
232 * creates an empty grptb
233 * Return:
234 * 0 if ok, -1 otherwise
235 */
236 static int
grptb_start(void)237 grptb_start(void)
238 {
239
240 if (grptb != NULL)
241 return (0);
242 if (grptb_fail)
243 return (-1);
244 if ((grptb = (GIDC **)calloc(GNM_SZ, sizeof(GIDC *))) == NULL) {
245 ++grptb_fail;
246 return (-1);
247 }
248 return (0);
249 }
250
251 /*
252 * user_from_uid()
253 * caches the name (if any) for the uid. If noname clear, we always
254 * return the stored name (if valid or invalid match).
255 * We use a simple hash table.
256 * Return
257 * Pointer to stored name (or a empty string)
258 */
259 const char *
user_from_uid(uid_t uid,int noname)260 user_from_uid(uid_t uid, int noname)
261 {
262 struct passwd *pw;
263 UIDC *ptr, **pptr;
264
265 if ((uidtb == NULL) && (uidtb_start() < 0))
266 return (NULL);
267
268 /*
269 * see if we have this uid cached
270 */
271 pptr = uidtb + (uid % UID_SZ);
272 ptr = *pptr;
273
274 if ((ptr != NULL) && (ptr->valid > 0) && (ptr->uid == uid)) {
275 /*
276 * have an entry for this uid
277 */
278 if (!noname || (ptr->valid == VALID))
279 return (ptr->name);
280 return (NULL);
281 }
282
283 /*
284 * No entry for this uid, we will add it
285 */
286 if (!pwopn) {
287 if (_pwcache_setpassent != NULL)
288 (*_pwcache_setpassent)(1);
289 ++pwopn;
290 }
291
292 if (ptr == NULL)
293 *pptr = ptr = (UIDC *)malloc(sizeof(UIDC));
294
295 if ((pw = (*_pwcache_getpwuid)(uid)) == NULL) {
296 /*
297 * no match for this uid in the local password file
298 * a string that is the uid in numeric format
299 */
300 if (ptr == NULL)
301 return (NULL);
302 ptr->uid = uid;
303 (void)snprintf(ptr->name, UNMLEN, "%lu", (long) uid);
304 ptr->valid = INVALID;
305 if (noname)
306 return (NULL);
307 } else {
308 /*
309 * there is an entry for this uid in the password file
310 */
311 if (ptr == NULL)
312 return (pw->pw_name);
313 ptr->uid = uid;
314 (void)strlcpy(ptr->name, pw->pw_name, UNMLEN);
315 ptr->valid = VALID;
316 }
317 return (ptr->name);
318 }
319
320 /*
321 * group_from_gid()
322 * caches the name (if any) for the gid. If noname clear, we always
323 * return the stored name (if valid or invalid match).
324 * We use a simple hash table.
325 * Return
326 * Pointer to stored name (or a empty string)
327 */
328 const char *
group_from_gid(gid_t gid,int noname)329 group_from_gid(gid_t gid, int noname)
330 {
331 struct group *gr;
332 GIDC *ptr, **pptr;
333
334 if ((gidtb == NULL) && (gidtb_start() < 0))
335 return (NULL);
336
337 /*
338 * see if we have this gid cached
339 */
340 pptr = gidtb + (gid % GID_SZ);
341 ptr = *pptr;
342
343 if ((ptr != NULL) && (ptr->valid > 0) && (ptr->gid == gid)) {
344 /*
345 * have an entry for this gid
346 */
347 if (!noname || (ptr->valid == VALID))
348 return (ptr->name);
349 return (NULL);
350 }
351
352 /*
353 * No entry for this gid, we will add it
354 */
355 if (!gropn) {
356 if (_pwcache_setgroupent != NULL)
357 (*_pwcache_setgroupent)(1);
358 ++gropn;
359 }
360
361 if (ptr == NULL)
362 *pptr = ptr = (GIDC *)malloc(sizeof(GIDC));
363
364 if ((gr = (*_pwcache_getgrgid)(gid)) == NULL) {
365 /*
366 * no match for this gid in the local group file, put in
367 * a string that is the gid in numeric format
368 */
369 if (ptr == NULL)
370 return (NULL);
371 ptr->gid = gid;
372 (void)snprintf(ptr->name, GNMLEN, "%lu", (long) gid);
373 ptr->valid = INVALID;
374 if (noname)
375 return (NULL);
376 } else {
377 /*
378 * there is an entry for this group in the group file
379 */
380 if (ptr == NULL)
381 return (gr->gr_name);
382 ptr->gid = gid;
383 (void)strlcpy(ptr->name, gr->gr_name, GNMLEN);
384 ptr->valid = VALID;
385 }
386 return (ptr->name);
387 }
388
389 /*
390 * uid_from_user()
391 * caches the uid for a given user name. We use a simple hash table.
392 * Return
393 * the uid (if any) for a user name, or a -1 if no match can be found
394 */
395 int
uid_from_user(const char * name,uid_t * uid)396 uid_from_user(const char *name, uid_t *uid)
397 {
398 struct passwd *pw;
399 UIDC *ptr, **pptr;
400 size_t namelen;
401
402 /*
403 * return -1 for mangled names
404 */
405 if (name == NULL || ((namelen = strlen(name)) == 0))
406 return (-1);
407 if ((usrtb == NULL) && (usrtb_start() < 0))
408 return (-1);
409
410 /*
411 * look up in hash table, if found and valid return the uid,
412 * if found and invalid, return a -1
413 */
414 pptr = usrtb + st_hash(name, namelen, UNM_SZ);
415 ptr = *pptr;
416
417 if ((ptr != NULL) && (ptr->valid > 0) && !strcmp(name, ptr->name)) {
418 if (ptr->valid == INVALID)
419 return (-1);
420 *uid = ptr->uid;
421 return (0);
422 }
423
424 if (!pwopn) {
425 if (_pwcache_setpassent != NULL)
426 (*_pwcache_setpassent)(1);
427 ++pwopn;
428 }
429
430 if (ptr == NULL)
431 *pptr = ptr = (UIDC *)malloc(sizeof(UIDC));
432
433 /*
434 * no match, look it up, if no match store it as an invalid entry,
435 * or store the matching uid
436 */
437 if (ptr == NULL) {
438 if ((pw = (*_pwcache_getpwnam)(name)) == NULL)
439 return (-1);
440 *uid = pw->pw_uid;
441 return (0);
442 }
443 (void)strlcpy(ptr->name, name, UNMLEN);
444 if ((pw = (*_pwcache_getpwnam)(name)) == NULL) {
445 ptr->valid = INVALID;
446 return (-1);
447 }
448 ptr->valid = VALID;
449 *uid = ptr->uid = pw->pw_uid;
450 return (0);
451 }
452
453 /*
454 * gid_from_group()
455 * caches the gid for a given group name. We use a simple hash table.
456 * Return
457 * the gid (if any) for a group name, or a -1 if no match can be found
458 */
459 int
gid_from_group(const char * name,gid_t * gid)460 gid_from_group(const char *name, gid_t *gid)
461 {
462 struct group *gr;
463 GIDC *ptr, **pptr;
464 size_t namelen;
465
466 /*
467 * return -1 for mangled names
468 */
469 if (name == NULL || ((namelen = strlen(name)) == 0))
470 return (-1);
471 if ((grptb == NULL) && (grptb_start() < 0))
472 return (-1);
473
474 /*
475 * look up in hash table, if found and valid return the uid,
476 * if found and invalid, return a -1
477 */
478 pptr = grptb + st_hash(name, namelen, GID_SZ);
479 ptr = *pptr;
480
481 if ((ptr != NULL) && (ptr->valid > 0) && !strcmp(name, ptr->name)) {
482 if (ptr->valid == INVALID)
483 return (-1);
484 *gid = ptr->gid;
485 return (0);
486 }
487
488 if (!gropn) {
489 if (_pwcache_setgroupent != NULL)
490 (*_pwcache_setgroupent)(1);
491 ++gropn;
492 }
493
494 if (ptr == NULL)
495 *pptr = ptr = (GIDC *)malloc(sizeof(GIDC));
496
497 /*
498 * no match, look it up, if no match store it as an invalid entry,
499 * or store the matching gid
500 */
501 if (ptr == NULL) {
502 if ((gr = (*_pwcache_getgrnam)(name)) == NULL)
503 return (-1);
504 *gid = gr->gr_gid;
505 return (0);
506 }
507
508 (void)strlcpy(ptr->name, name, GNMLEN);
509 if ((gr = (*_pwcache_getgrnam)(name)) == NULL) {
510 ptr->valid = INVALID;
511 return (-1);
512 }
513 ptr->valid = VALID;
514 *gid = ptr->gid = gr->gr_gid;
515 return (0);
516 }
517
518 #define FLUSHTB(arr, len, fail) \
519 do { \
520 if (arr != NULL) { \
521 for (i = 0; i < len; i++) \
522 if (arr[i] != NULL) \
523 free(arr[i]); \
524 arr = NULL; \
525 } \
526 fail = 0; \
527 } while (0)
528
529 int
pwcache_userdb(int (* a_setpassent)(int),void (* a_endpwent)(void),struct passwd * (* a_getpwnam)(const char *),struct passwd * (* a_getpwuid)(uid_t))530 pwcache_userdb(
531 int (*a_setpassent)(int),
532 void (*a_endpwent)(void),
533 struct passwd * (*a_getpwnam)(const char *),
534 struct passwd * (*a_getpwuid)(uid_t))
535 {
536 int i;
537
538 /* a_setpassent and a_endpwent may be NULL */
539 if (a_getpwnam == NULL || a_getpwuid == NULL)
540 return (-1);
541
542 if (_pwcache_endpwent != NULL)
543 (*_pwcache_endpwent)();
544 FLUSHTB(uidtb, UID_SZ, uidtb_fail);
545 FLUSHTB(usrtb, UNM_SZ, usrtb_fail);
546 pwopn = 0;
547 _pwcache_setpassent = a_setpassent;
548 _pwcache_endpwent = a_endpwent;
549 _pwcache_getpwnam = a_getpwnam;
550 _pwcache_getpwuid = a_getpwuid;
551
552 return (0);
553 }
554
555 int
pwcache_groupdb(int (* a_setgroupent)(int),void (* a_endgrent)(void),struct group * (* a_getgrnam)(const char *),struct group * (* a_getgrgid)(gid_t))556 pwcache_groupdb(
557 int (*a_setgroupent)(int),
558 void (*a_endgrent)(void),
559 struct group * (*a_getgrnam)(const char *),
560 struct group * (*a_getgrgid)(gid_t))
561 {
562 int i;
563
564 /* a_setgroupent and a_endgrent may be NULL */
565 if (a_getgrnam == NULL || a_getgrgid == NULL)
566 return (-1);
567
568 if (_pwcache_endgrent != NULL)
569 (*_pwcache_endgrent)();
570 FLUSHTB(gidtb, GID_SZ, gidtb_fail);
571 FLUSHTB(grptb, GNM_SZ, grptb_fail);
572 gropn = 0;
573 _pwcache_setgroupent = a_setgroupent;
574 _pwcache_endgrent = a_endgrent;
575 _pwcache_getgrnam = a_getgrnam;
576 _pwcache_getgrgid = a_getgrgid;
577
578 return (0);
579 }
580
581
582 #ifdef TEST_PWCACHE
583
584 struct passwd *
test_getpwnam(const char * name)585 test_getpwnam(const char *name)
586 {
587 static struct passwd foo;
588
589 memset(&foo, 0, sizeof(foo));
590 if (strcmp(name, "toor") == 0) {
591 foo.pw_uid = 666;
592 return &foo;
593 }
594 return (getpwnam(name));
595 }
596
597 int
main(int argc,char * argv[])598 main(int argc, char *argv[])
599 {
600 uid_t u;
601 int r, i;
602
603 printf("pass 1 (default userdb)\n");
604 for (i = 1; i < argc; i++) {
605 printf("i: %d, pwopn %d usrtb_fail %d usrtb %p\n",
606 i, pwopn, usrtb_fail, usrtb);
607 r = uid_from_user(argv[i], &u);
608 if (r == -1)
609 printf(" uid_from_user %s: failed\n", argv[i]);
610 else
611 printf(" uid_from_user %s: %d\n", argv[i], u);
612 }
613 printf("pass 1 finish: pwopn %d usrtb_fail %d usrtb %p\n",
614 pwopn, usrtb_fail, usrtb);
615
616 puts("");
617 printf("pass 2 (replacement userdb)\n");
618 printf("pwcache_userdb returned %d\n",
619 pwcache_userdb(setpassent, test_getpwnam, getpwuid));
620 printf("pwopn %d usrtb_fail %d usrtb %p\n", pwopn, usrtb_fail, usrtb);
621
622 for (i = 1; i < argc; i++) {
623 printf("i: %d, pwopn %d usrtb_fail %d usrtb %p\n",
624 i, pwopn, usrtb_fail, usrtb);
625 u = -1;
626 r = uid_from_user(argv[i], &u);
627 if (r == -1)
628 printf(" uid_from_user %s: failed\n", argv[i]);
629 else
630 printf(" uid_from_user %s: %d\n", argv[i], u);
631 }
632 printf("pass 2 finish: pwopn %d usrtb_fail %d usrtb %p\n",
633 pwopn, usrtb_fail, usrtb);
634
635 puts("");
636 printf("pass 3 (null pointers)\n");
637 printf("pwcache_userdb returned %d\n",
638 pwcache_userdb(NULL, NULL, NULL));
639
640 return (0);
641 }
642 #endif /* TEST_PWCACHE */
643 #endif /* !HAVE_PWCACHE_USERDB */
644