1/* Copyright (C) 1996-2021 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Thorsten Kukuk <kukuk@suse.de>, 1996.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <ctype.h>
20#include <errno.h>
21#include <fcntl.h>
22#include <grp.h>
23#include <nss.h>
24#include <nsswitch.h>
25#include <stdio_ext.h>
26#include <string.h>
27#include <libc-lock.h>
28#include <kernel-features.h>
29#include <nss_files.h>
30
31NSS_DECLARE_MODULE_FUNCTIONS (compat)
32
33static nss_action_list ni;
34static enum nss_status (*setgrent_impl) (int stayopen);
35static enum nss_status (*getgrnam_r_impl) (const char *name,
36 struct group * grp, char *buffer,
37 size_t buflen, int *errnop);
38static enum nss_status (*getgrgid_r_impl) (gid_t gid, struct group * grp,
39 char *buffer, size_t buflen,
40 int *errnop);
41static enum nss_status (*getgrent_r_impl) (struct group * grp, char *buffer,
42 size_t buflen, int *errnop);
43static enum nss_status (*endgrent_impl) (void);
44
45/* Get the declaration of the parser function. */
46#define ENTNAME grent
47#define STRUCTURE group
48#define EXTERN_PARSER
49#include <nss/nss_files/files-parse.c>
50
51/* Structure for remembering -group members ... */
52#define BLACKLIST_INITIAL_SIZE 512
53#define BLACKLIST_INCREMENT 256
54struct blacklist_t
55{
56 char *data;
57 int current;
58 int size;
59};
60
61struct ent_t
62{
63 bool files;
64 enum nss_status setent_status;
65 FILE *stream;
66 struct blacklist_t blacklist;
67};
68typedef struct ent_t ent_t;
69
70static ent_t ext_ent = { true, NSS_STATUS_SUCCESS, NULL, { NULL, 0, 0 }};
71
72/* Protect global state against multiple changers. */
73__libc_lock_define_initialized (static, lock)
74
75/* Prototypes for local functions. */
76static void blacklist_store_name (const char *, ent_t *);
77static bool in_blacklist (const char *, int, ent_t *);
78
79/* Initialize the NSS interface/functions. The calling function must
80 hold the lock. */
81static void
82init_nss_interface (void)
83{
84 if (__nss_database_lookup2 ("group_compat", NULL, "nis", &ni) >= 0)
85 {
86 setgrent_impl = __nss_lookup_function (ni, "setgrent");
87 getgrnam_r_impl = __nss_lookup_function (ni, "getgrnam_r");
88 getgrgid_r_impl = __nss_lookup_function (ni, "getgrgid_r");
89 getgrent_r_impl = __nss_lookup_function (ni, "getgrent_r");
90 endgrent_impl = __nss_lookup_function (ni, "endgrent");
91 }
92}
93
94static enum nss_status
95internal_setgrent (ent_t *ent, int stayopen, int needent)
96{
97 enum nss_status status = NSS_STATUS_SUCCESS;
98
99 ent->files = true;
100
101 if (ent->blacklist.data != NULL)
102 {
103 ent->blacklist.current = 1;
104 ent->blacklist.data[0] = '|';
105 ent->blacklist.data[1] = '\0';
106 }
107 else
108 ent->blacklist.current = 0;
109
110 if (ent->stream == NULL)
111 {
112 ent->stream = __nss_files_fopen ("/etc/group");
113
114 if (ent->stream == NULL)
115 status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
116 }
117 else
118 rewind (ent->stream);
119
120 if (needent && status == NSS_STATUS_SUCCESS && setgrent_impl)
121 ent->setent_status = setgrent_impl (stayopen);
122
123 return status;
124}
125
126
127enum nss_status
128_nss_compat_setgrent (int stayopen)
129{
130 enum nss_status result;
131
132 __libc_lock_lock (lock);
133
134 if (ni == NULL)
135 init_nss_interface ();
136
137 result = internal_setgrent (&ext_ent, stayopen, 1);
138
139 __libc_lock_unlock (lock);
140
141 return result;
142}
143
144
145static enum nss_status __attribute_warn_unused_result__
146internal_endgrent (ent_t *ent)
147{
148 if (ent->stream != NULL)
149 {
150 fclose (ent->stream);
151 ent->stream = NULL;
152 }
153
154 if (ent->blacklist.data != NULL)
155 {
156 ent->blacklist.current = 1;
157 ent->blacklist.data[0] = '|';
158 ent->blacklist.data[1] = '\0';
159 }
160 else
161 ent->blacklist.current = 0;
162
163 return NSS_STATUS_SUCCESS;
164}
165
166/* Like internal_endgrent, but preserve errno in all cases. */
167static void
168internal_endgrent_noerror (ent_t *ent)
169{
170 int saved_errno = errno;
171 enum nss_status unused __attribute__ ((unused)) = internal_endgrent (ent);
172 __set_errno (saved_errno);
173}
174
175enum nss_status
176_nss_compat_endgrent (void)
177{
178 enum nss_status result;
179
180 __libc_lock_lock (lock);
181
182 if (endgrent_impl)
183 endgrent_impl ();
184
185 result = internal_endgrent (&ext_ent);
186
187 __libc_lock_unlock (lock);
188
189 return result;
190}
191
192/* get the next group from NSS (+ entry) */
193static enum nss_status
194getgrent_next_nss (struct group *result, ent_t *ent, char *buffer,
195 size_t buflen, int *errnop)
196{
197 if (!getgrent_r_impl)
198 return NSS_STATUS_UNAVAIL;
199
200 /* If the setgrent call failed, say so. */
201 if (ent->setent_status != NSS_STATUS_SUCCESS)
202 return ent->setent_status;
203
204 do
205 {
206 enum nss_status status;
207
208 if ((status = getgrent_r_impl (result, buffer, buflen, errnop))
209 != NSS_STATUS_SUCCESS)
210 return status;
211 }
212 while (in_blacklist (result->gr_name, strlen (result->gr_name), ent));
213
214 return NSS_STATUS_SUCCESS;
215}
216
217/* This function handle the +group entrys in /etc/group */
218static enum nss_status
219getgrnam_plusgroup (const char *name, struct group *result, ent_t *ent,
220 char *buffer, size_t buflen, int *errnop)
221{
222 if (!getgrnam_r_impl)
223 return NSS_STATUS_UNAVAIL;
224
225 enum nss_status status = getgrnam_r_impl (name, result, buffer, buflen,
226 errnop);
227 if (status != NSS_STATUS_SUCCESS)
228 return status;
229
230 if (in_blacklist (result->gr_name, strlen (result->gr_name), ent))
231 return NSS_STATUS_NOTFOUND;
232
233 /* We found the entry. */
234 return NSS_STATUS_SUCCESS;
235}
236
237static enum nss_status
238getgrent_next_file (struct group *result, ent_t *ent,
239 char *buffer, size_t buflen, int *errnop)
240{
241 struct parser_data *data = (void *) buffer;
242 while (1)
243 {
244 fpos_t pos;
245 int parse_res = 0;
246 char *p;
247
248 do
249 {
250 /* We need at least 3 characters for one line. */
251 if (__glibc_unlikely (buflen < 3))
252 {
253 erange:
254 *errnop = ERANGE;
255 return NSS_STATUS_TRYAGAIN;
256 }
257
258 fgetpos (ent->stream, &pos);
259 buffer[buflen - 1] = '\xff';
260 p = fgets_unlocked (buffer, buflen, ent->stream);
261 if (p == NULL && feof_unlocked (ent->stream))
262 return NSS_STATUS_NOTFOUND;
263
264 if (p == NULL || __builtin_expect (buffer[buflen - 1] != '\xff', 0))
265 {
266 erange_reset:
267 fsetpos (ent->stream, &pos);
268 goto erange;
269 }
270
271 /* Terminate the line for any case. */
272 buffer[buflen - 1] = '\0';
273
274 /* Skip leading blanks. */
275 while (isspace (*p))
276 ++p;
277 }
278 while (*p == '\0' || *p == '#' /* Ignore empty and comment lines. */
279 /* Parse the line. If it is invalid, loop to
280 get the next line of the file to parse. */
281 || !(parse_res = _nss_files_parse_grent (p, result, data, buflen,
282 errnop)));
283
284 if (__glibc_unlikely (parse_res == -1))
285 /* The parser ran out of space. */
286 goto erange_reset;
287
288 if (result->gr_name[0] != '+' && result->gr_name[0] != '-')
289 /* This is a real entry. */
290 break;
291
292 /* -group */
293 if (result->gr_name[0] == '-' && result->gr_name[1] != '\0'
294 && result->gr_name[1] != '@')
295 {
296 blacklist_store_name (&result->gr_name[1], ent);
297 continue;
298 }
299
300 /* +group */
301 if (result->gr_name[0] == '+' && result->gr_name[1] != '\0'
302 && result->gr_name[1] != '@')
303 {
304 size_t len = strlen (result->gr_name);
305 char buf[len];
306 enum nss_status status;
307
308 /* Store the group in the blacklist for the "+" at the end of
309 /etc/group */
310 memcpy (buf, &result->gr_name[1], len);
311 status = getgrnam_plusgroup (&result->gr_name[1], result, ent,
312 buffer, buflen, errnop);
313 blacklist_store_name (buf, ent);
314 if (status == NSS_STATUS_SUCCESS) /* We found the entry. */
315 break;
316 else if (status == NSS_STATUS_RETURN /* We couldn't parse the entry*/
317 || status == NSS_STATUS_NOTFOUND) /* No group in NIS */
318 continue;
319 else
320 {
321 if (status == NSS_STATUS_TRYAGAIN)
322 /* The parser ran out of space. */
323 goto erange_reset;
324
325 return status;
326 }
327 }
328
329 /* +:... */
330 if (result->gr_name[0] == '+' && result->gr_name[1] == '\0')
331 {
332 ent->files = false;
333
334 return getgrent_next_nss (result, ent, buffer, buflen, errnop);
335 }
336 }
337
338 return NSS_STATUS_SUCCESS;
339}
340
341
342enum nss_status
343_nss_compat_getgrent_r (struct group *grp, char *buffer, size_t buflen,
344 int *errnop)
345{
346 enum nss_status result = NSS_STATUS_SUCCESS;
347
348 __libc_lock_lock (lock);
349
350 /* Be prepared that the setgrent function was not called before. */
351 if (ni == NULL)
352 init_nss_interface ();
353
354 if (ext_ent.stream == NULL)
355 result = internal_setgrent (&ext_ent, 1, 1);
356
357 if (result == NSS_STATUS_SUCCESS)
358 {
359 if (ext_ent.files)
360 result = getgrent_next_file (grp, &ext_ent, buffer, buflen, errnop);
361 else
362 result = getgrent_next_nss (grp, &ext_ent, buffer, buflen, errnop);
363 }
364 __libc_lock_unlock (lock);
365
366 return result;
367}
368
369/* Searches in /etc/group and the NIS/NIS+ map for a special group */
370static enum nss_status
371internal_getgrnam_r (const char *name, struct group *result, ent_t *ent,
372 char *buffer, size_t buflen, int *errnop)
373{
374 struct parser_data *data = (void *) buffer;
375 while (1)
376 {
377 fpos_t pos;
378 int parse_res = 0;
379 char *p;
380
381 do
382 {
383 /* We need at least 3 characters for one line. */
384 if (__glibc_unlikely (buflen < 3))
385 {
386 erange:
387 *errnop = ERANGE;
388 return NSS_STATUS_TRYAGAIN;
389 }
390
391 fgetpos (ent->stream, &pos);
392 buffer[buflen - 1] = '\xff';
393 p = fgets_unlocked (buffer, buflen, ent->stream);
394 if (p == NULL && feof_unlocked (ent->stream))
395 return NSS_STATUS_NOTFOUND;
396
397 if (p == NULL || __builtin_expect (buffer[buflen - 1] != '\xff', 0))
398 {
399 erange_reset:
400 fsetpos (ent->stream, &pos);
401 goto erange;
402 }
403
404 /* Terminate the line for any case. */
405 buffer[buflen - 1] = '\0';
406
407 /* Skip leading blanks. */
408 while (isspace (*p))
409 ++p;
410 }
411 while (*p == '\0' || *p == '#' /* Ignore empty and comment lines. */
412 /* Parse the line. If it is invalid, loop to
413 get the next line of the file to parse. */
414 || !(parse_res = _nss_files_parse_grent (p, result, data, buflen,
415 errnop)));
416
417 if (__glibc_unlikely (parse_res == -1))
418 /* The parser ran out of space. */
419 goto erange_reset;
420
421 /* This is a real entry. */
422 if (result->gr_name[0] != '+' && result->gr_name[0] != '-')
423 {
424 if (strcmp (result->gr_name, name) == 0)
425 return NSS_STATUS_SUCCESS;
426 else
427 continue;
428 }
429
430 /* -group */
431 if (result->gr_name[0] == '-' && result->gr_name[1] != '\0')
432 {
433 if (strcmp (&result->gr_name[1], name) == 0)
434 return NSS_STATUS_NOTFOUND;
435 else
436 continue;
437 }
438
439 /* +group */
440 if (result->gr_name[0] == '+' && result->gr_name[1] != '\0')
441 {
442 if (strcmp (name, &result->gr_name[1]) == 0)
443 {
444 enum nss_status status;
445
446 status = getgrnam_plusgroup (name, result, ent,
447 buffer, buflen, errnop);
448 if (status == NSS_STATUS_RETURN)
449 /* We couldn't parse the entry */
450 continue;
451 else
452 return status;
453 }
454 }
455 /* +:... */
456 if (result->gr_name[0] == '+' && result->gr_name[1] == '\0')
457 {
458 enum nss_status status;
459
460 status = getgrnam_plusgroup (name, result, ent,
461 buffer, buflen, errnop);
462 if (status == NSS_STATUS_RETURN)
463 /* We couldn't parse the entry */
464 continue;
465 else
466 return status;
467 }
468 }
469
470 return NSS_STATUS_SUCCESS;
471}
472
473enum nss_status
474_nss_compat_getgrnam_r (const char *name, struct group *grp,
475 char *buffer, size_t buflen, int *errnop)
476{
477 ent_t ent = { true, NSS_STATUS_SUCCESS, NULL, { NULL, 0, 0 }};
478 enum nss_status result;
479
480 if (name[0] == '-' || name[0] == '+')
481 return NSS_STATUS_NOTFOUND;
482
483 __libc_lock_lock (lock);
484
485 if (ni == NULL)
486 init_nss_interface ();
487
488 __libc_lock_unlock (lock);
489
490 result = internal_setgrent (&ent, 0, 0);
491
492 if (result == NSS_STATUS_SUCCESS)
493 result = internal_getgrnam_r (name, grp, &ent, buffer, buflen, errnop);
494
495 internal_endgrent_noerror (&ent);
496
497 return result;
498}
499
500/* Searches in /etc/group and the NIS/NIS+ map for a special group id */
501static enum nss_status
502internal_getgrgid_r (gid_t gid, struct group *result, ent_t *ent,
503 char *buffer, size_t buflen, int *errnop)
504{
505 struct parser_data *data = (void *) buffer;
506 while (1)
507 {
508 fpos_t pos;
509 int parse_res = 0;
510 char *p;
511
512 do
513 {
514 /* We need at least 3 characters for one line. */
515 if (__glibc_unlikely (buflen < 3))
516 {
517 erange:
518 *errnop = ERANGE;
519 return NSS_STATUS_TRYAGAIN;
520 }
521
522 fgetpos (ent->stream, &pos);
523 buffer[buflen - 1] = '\xff';
524 p = fgets_unlocked (buffer, buflen, ent->stream);
525 if (p == NULL && feof_unlocked (ent->stream))
526 return NSS_STATUS_NOTFOUND;
527
528 if (p == NULL || __builtin_expect (buffer[buflen - 1] != '\xff', 0))
529 {
530 erange_reset:
531 fsetpos (ent->stream, &pos);
532 goto erange;
533 }
534
535 /* Terminate the line for any case. */
536 buffer[buflen - 1] = '\0';
537
538 /* Skip leading blanks. */
539 while (isspace (*p))
540 ++p;
541 }
542 while (*p == '\0' || *p == '#' /* Ignore empty and comment lines. */
543 /* Parse the line. If it is invalid, loop to
544 get the next line of the file to parse. */
545 || !(parse_res = _nss_files_parse_grent (p, result, data, buflen,
546 errnop)));
547
548 if (__glibc_unlikely (parse_res == -1))
549 /* The parser ran out of space. */
550 goto erange_reset;
551
552 /* This is a real entry. */
553 if (result->gr_name[0] != '+' && result->gr_name[0] != '-')
554 {
555 if (result->gr_gid == gid)
556 return NSS_STATUS_SUCCESS;
557 else
558 continue;
559 }
560
561 /* -group */
562 if (result->gr_name[0] == '-' && result->gr_name[1] != '\0')
563 {
564 blacklist_store_name (&result->gr_name[1], ent);
565 continue;
566 }
567
568 /* +group */
569 if (result->gr_name[0] == '+' && result->gr_name[1] != '\0')
570 {
571 /* Yes, no +1, see the memcpy call below. */
572 size_t len = strlen (result->gr_name);
573 char buf[len];
574 enum nss_status status;
575
576 /* Store the group in the blacklist for the "+" at the end of
577 /etc/group */
578 memcpy (buf, &result->gr_name[1], len);
579 status = getgrnam_plusgroup (&result->gr_name[1], result, ent,
580 buffer, buflen, errnop);
581 blacklist_store_name (buf, ent);
582 if (status == NSS_STATUS_SUCCESS && result->gr_gid == gid)
583 break;
584 else
585 continue;
586 }
587 /* +:... */
588 if (result->gr_name[0] == '+' && result->gr_name[1] == '\0')
589 {
590 if (!getgrgid_r_impl)
591 return NSS_STATUS_UNAVAIL;
592
593 enum nss_status status = getgrgid_r_impl (gid, result,
594 buffer, buflen, errnop);
595 if (status == NSS_STATUS_RETURN) /* We couldn't parse the entry */
596 return NSS_STATUS_NOTFOUND;
597 else
598 return status;
599 }
600 }
601
602 return NSS_STATUS_SUCCESS;
603}
604
605enum nss_status
606_nss_compat_getgrgid_r (gid_t gid, struct group *grp,
607 char *buffer, size_t buflen, int *errnop)
608{
609 ent_t ent = { true, NSS_STATUS_SUCCESS, NULL, { NULL, 0, 0 }};
610 enum nss_status result;
611
612 __libc_lock_lock (lock);
613
614 if (ni == NULL)
615 init_nss_interface ();
616
617 __libc_lock_unlock (lock);
618
619 result = internal_setgrent (&ent, 0, 0);
620
621 if (result == NSS_STATUS_SUCCESS)
622 result = internal_getgrgid_r (gid, grp, &ent, buffer, buflen, errnop);
623
624 internal_endgrent_noerror (&ent);
625
626 return result;
627}
628
629
630/* Support routines for remembering -@netgroup and -user entries.
631 The names are stored in a single string with `|' as separator. */
632static void
633blacklist_store_name (const char *name, ent_t *ent)
634{
635 int namelen = strlen (name);
636 char *tmp;
637
638 /* first call, setup cache */
639 if (ent->blacklist.size == 0)
640 {
641 ent->blacklist.size = MAX (BLACKLIST_INITIAL_SIZE, 2 * namelen);
642 ent->blacklist.data = malloc (ent->blacklist.size);
643 if (ent->blacklist.data == NULL)
644 return;
645 ent->blacklist.data[0] = '|';
646 ent->blacklist.data[1] = '\0';
647 ent->blacklist.current = 1;
648 }
649 else
650 {
651 if (in_blacklist (name, namelen, ent))
652 return; /* no duplicates */
653
654 if (ent->blacklist.current + namelen + 1 >= ent->blacklist.size)
655 {
656 ent->blacklist.size += MAX (BLACKLIST_INCREMENT, 2 * namelen);
657 tmp = realloc (ent->blacklist.data, ent->blacklist.size);
658 if (tmp == NULL)
659 {
660 free (ent->blacklist.data);
661 ent->blacklist.size = 0;
662 return;
663 }
664 ent->blacklist.data = tmp;
665 }
666 }
667
668 tmp = stpcpy (ent->blacklist.data + ent->blacklist.current, name);
669 *tmp++ = '|';
670 *tmp = '\0';
671 ent->blacklist.current += namelen + 1;
672
673 return;
674}
675
676/* Return whether ent->blacklist contains name. */
677static bool
678in_blacklist (const char *name, int namelen, ent_t *ent)
679{
680 char buf[namelen + 3];
681 char *cp;
682
683 if (ent->blacklist.data == NULL)
684 return false;
685
686 buf[0] = '|';
687 cp = stpcpy (&buf[1], name);
688 *cp++ = '|';
689 *cp = '\0';
690 return strstr (ent->blacklist.data, buf) != NULL;
691}
692