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1 | /* | |
2 | * nonlocal-group.c | |
3 | * group database for nss_nonlocal proxy | |
4 | * | |
5 | * Copyright © 2007–2010 Anders Kaseorg <andersk@mit.edu> and Tim | |
6 | * Abbott <tabbott@mit.edu> | |
7 | * | |
8 | * This file is part of nss_nonlocal. | |
9 | * | |
10 | * nss_nonlocal is free software; you can redistribute it and/or | |
11 | * modify it under the terms of the GNU Lesser General Public License | |
12 | * as published by the Free Software Foundation; either version 2.1 of | |
13 | * the License, or (at your option) any later version. | |
14 | * | |
15 | * nss_nonlocal is distributed in the hope that it will be useful, but | |
16 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
18 | * Lesser General Public License for more details. | |
19 | * | |
20 | * You should have received a copy of the GNU Lesser General Public | |
21 | * License along with nss_nonlocal; if not, write to the Free Software | |
22 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA | |
23 | * 02110-1301 USA | |
24 | */ | |
25 | ||
26 | #define _GNU_SOURCE | |
27 | #include <sys/types.h> | |
28 | #include <unistd.h> | |
29 | #include <stdlib.h> | |
30 | #include <stdint.h> | |
31 | #include <string.h> | |
32 | #include <dlfcn.h> | |
33 | #include <stdio.h> | |
34 | #include <syslog.h> | |
35 | #include <errno.h> | |
36 | #include <grp.h> | |
37 | #include <nss.h> | |
38 | #include "nsswitch-internal.h" | |
39 | #include "nonlocal.h" | |
40 | ||
41 | #define MAGIC_NONLOCAL_GROUPNAME "nss-nonlocal-users" | |
42 | #define MAGIC_LOCAL_GROUPNAME "nss-local-users" | |
43 | ||
44 | ||
45 | enum nss_status | |
46 | _nss_nonlocal_getgrnam_r(const char *name, struct group *grp, | |
47 | char *buffer, size_t buflen, int *errnop); | |
48 | ||
49 | enum nss_status | |
50 | _nss_nonlocal_getgrgid_r(gid_t gid, struct group *grp, | |
51 | char *buffer, size_t buflen, int *errnop); | |
52 | ||
53 | ||
54 | static service_user * | |
55 | nss_group_nonlocal_database(void) | |
56 | { | |
57 | static service_user *nip = NULL; | |
58 | if (nip == NULL) | |
59 | __nss_database_lookup("group_nonlocal", NULL, "", &nip); | |
60 | ||
61 | return nip; | |
62 | } | |
63 | ||
64 | ||
65 | enum nss_status | |
66 | check_nonlocal_gid(const char *user, gid_t gid, int *errnop) | |
67 | { | |
68 | static const char *fct_name = "getgrgid_r"; | |
69 | static service_user *startp = NULL; | |
70 | static void *fct_start = NULL; | |
71 | enum nss_status status; | |
72 | service_user *nip; | |
73 | union { | |
74 | enum nss_status (*l)(gid_t gid, struct group *grp, | |
75 | char *buffer, size_t buflen, int *errnop); | |
76 | void *ptr; | |
77 | } fct; | |
78 | struct group gbuf; | |
79 | int old_errno = errno; | |
80 | ||
81 | size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX); | |
82 | char *buf = malloc(buflen); | |
83 | if (buf == NULL) { | |
84 | *errnop = ENOMEM; | |
85 | errno = old_errno; | |
86 | return NSS_STATUS_TRYAGAIN; | |
87 | } | |
88 | ||
89 | if (fct_start == NULL && | |
90 | __nss_group_lookup(&startp, fct_name, &fct_start) != 0) { | |
91 | free(buf); | |
92 | return NSS_STATUS_UNAVAIL; | |
93 | } | |
94 | nip = startp; | |
95 | fct.ptr = fct_start; | |
96 | do { | |
97 | morebuf: | |
98 | if (fct.l == _nss_nonlocal_getgrgid_r) | |
99 | status = NSS_STATUS_NOTFOUND; | |
100 | else | |
101 | status = DL_CALL_FCT(fct.l, (gid, &gbuf, buf, buflen, errnop)); | |
102 | if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) { | |
103 | free(buf); | |
104 | buflen *= 2; | |
105 | buf = malloc(buflen); | |
106 | if (buf == NULL) { | |
107 | *errnop = ENOMEM; | |
108 | errno = old_errno; | |
109 | return NSS_STATUS_TRYAGAIN; | |
110 | } | |
111 | goto morebuf; | |
112 | } | |
113 | } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); | |
114 | ||
115 | if (status == NSS_STATUS_SUCCESS) { | |
116 | syslog(LOG_DEBUG, "nss_nonlocal: removing local group %u (%s) from non-local user %s\n", gbuf.gr_gid, gbuf.gr_name, user); | |
117 | status = NSS_STATUS_NOTFOUND; | |
118 | } else if (status != NSS_STATUS_TRYAGAIN) { | |
119 | status = NSS_STATUS_SUCCESS; | |
120 | } | |
121 | ||
122 | free(buf); | |
123 | return status; | |
124 | } | |
125 | ||
126 | enum nss_status | |
127 | check_nonlocal_group(const char *user, struct group *grp, int *errnop) | |
128 | { | |
129 | enum nss_status status = NSS_STATUS_SUCCESS; | |
130 | int old_errno = errno; | |
131 | char *end; | |
132 | unsigned long gid; | |
133 | ||
134 | errno = 0; | |
135 | gid = strtoul(grp->gr_name, &end, 10); | |
136 | if (errno == 0 && *end == '\0' && (gid_t)gid == gid) | |
137 | status = check_nonlocal_gid(user, gid, errnop); | |
138 | errno = old_errno; | |
139 | if (status != NSS_STATUS_SUCCESS) | |
140 | return status; | |
141 | ||
142 | return check_nonlocal_gid(user, grp->gr_gid, errnop); | |
143 | } | |
144 | ||
145 | enum nss_status | |
146 | get_local_group(const char *name, struct group *grp, char **buffer, int *errnop) | |
147 | { | |
148 | static const char *fct_name = "getgrnam_r"; | |
149 | static service_user *startp = NULL; | |
150 | static void *fct_start = NULL; | |
151 | enum nss_status status; | |
152 | service_user *nip; | |
153 | union { | |
154 | enum nss_status (*l)(const char *name, struct group *grp, | |
155 | char *buffer, size_t buflen, int *errnop); | |
156 | void *ptr; | |
157 | } fct; | |
158 | size_t buflen; | |
159 | int old_errno = errno; | |
160 | ||
161 | buflen = sysconf(_SC_GETGR_R_SIZE_MAX); | |
162 | *buffer = malloc(buflen); | |
163 | if (*buffer == NULL) { | |
164 | *errnop = ENOMEM; | |
165 | errno = old_errno; | |
166 | return NSS_STATUS_TRYAGAIN; | |
167 | } | |
168 | ||
169 | if (fct_start == NULL && | |
170 | __nss_group_lookup(&startp, fct_name, &fct_start) != 0) { | |
171 | free(*buffer); | |
172 | *buffer = NULL; | |
173 | return NSS_STATUS_UNAVAIL; | |
174 | } | |
175 | nip = startp; | |
176 | fct.ptr = fct_start; | |
177 | do { | |
178 | morebuf: | |
179 | if (fct.l == _nss_nonlocal_getgrnam_r) | |
180 | status = NSS_STATUS_NOTFOUND; | |
181 | else | |
182 | status = DL_CALL_FCT(fct.l, (name, grp, *buffer, buflen, errnop)); | |
183 | if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) { | |
184 | free(*buffer); | |
185 | buflen *= 2; | |
186 | *buffer = malloc(buflen); | |
187 | if (*buffer == NULL) { | |
188 | *errnop = ENOMEM; | |
189 | errno = old_errno; | |
190 | return NSS_STATUS_TRYAGAIN; | |
191 | } | |
192 | goto morebuf; | |
193 | } | |
194 | } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); | |
195 | ||
196 | if (status != NSS_STATUS_SUCCESS) { | |
197 | free(*buffer); | |
198 | *buffer = NULL; | |
199 | } | |
200 | ||
201 | return status; | |
202 | } | |
203 | ||
204 | static service_user *grent_nip = NULL; | |
205 | static void *grent_fct_start; | |
206 | static union { | |
207 | enum nss_status (*l)(struct group *grp, char *buffer, size_t buflen, | |
208 | int *errnop); | |
209 | void *ptr; | |
210 | } grent_fct; | |
211 | static const char *grent_fct_name = "getgrent_r"; | |
212 | ||
213 | enum nss_status | |
214 | _nss_nonlocal_setgrent(int stayopen) | |
215 | { | |
216 | static const char *fct_name = "setgrent"; | |
217 | static void *fct_start = NULL; | |
218 | enum nss_status status; | |
219 | service_user *nip; | |
220 | union { | |
221 | enum nss_status (*l)(int stayopen); | |
222 | void *ptr; | |
223 | } fct; | |
224 | ||
225 | nip = nss_group_nonlocal_database(); | |
226 | if (nip == NULL) | |
227 | return NSS_STATUS_UNAVAIL; | |
228 | if (fct_start == NULL) | |
229 | fct_start = __nss_lookup_function(nip, fct_name); | |
230 | fct.ptr = fct_start; | |
231 | do { | |
232 | if (fct.ptr == NULL) | |
233 | status = NSS_STATUS_UNAVAIL; | |
234 | else | |
235 | status = DL_CALL_FCT(fct.l, (stayopen)); | |
236 | } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); | |
237 | if (status != NSS_STATUS_SUCCESS) | |
238 | return status; | |
239 | ||
240 | grent_nip = nip; | |
241 | if (grent_fct_start == NULL) | |
242 | grent_fct_start = __nss_lookup_function(nip, grent_fct_name); | |
243 | grent_fct.ptr = grent_fct_start; | |
244 | return NSS_STATUS_SUCCESS; | |
245 | } | |
246 | ||
247 | enum nss_status | |
248 | _nss_nonlocal_endgrent(void) | |
249 | { | |
250 | static const char *fct_name = "endgrent"; | |
251 | static void *fct_start = NULL; | |
252 | enum nss_status status; | |
253 | service_user *nip; | |
254 | union { | |
255 | enum nss_status (*l)(void); | |
256 | void *ptr; | |
257 | } fct; | |
258 | ||
259 | grent_nip = NULL; | |
260 | ||
261 | nip = nss_group_nonlocal_database(); | |
262 | if (nip == NULL) | |
263 | return NSS_STATUS_UNAVAIL; | |
264 | if (fct_start == NULL) | |
265 | fct_start = __nss_lookup_function(nip, fct_name); | |
266 | fct.ptr = fct_start; | |
267 | do { | |
268 | if (fct.ptr == NULL) | |
269 | status = NSS_STATUS_UNAVAIL; | |
270 | else | |
271 | status = DL_CALL_FCT(fct.l, ()); | |
272 | } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); | |
273 | return status; | |
274 | } | |
275 | ||
276 | enum nss_status | |
277 | _nss_nonlocal_getgrent_r(struct group *grp, char *buffer, size_t buflen, | |
278 | int *errnop) | |
279 | { | |
280 | enum nss_status status; | |
281 | ||
282 | char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV); | |
283 | if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0') | |
284 | return NSS_STATUS_UNAVAIL; | |
285 | ||
286 | if (grent_nip == NULL) { | |
287 | status = _nss_nonlocal_setgrent(0); | |
288 | if (status != NSS_STATUS_SUCCESS) | |
289 | return status; | |
290 | } | |
291 | do { | |
292 | if (grent_fct.ptr == NULL) | |
293 | status = NSS_STATUS_UNAVAIL; | |
294 | else { | |
295 | int nonlocal_errno; | |
296 | do | |
297 | status = DL_CALL_FCT(grent_fct.l, (grp, buffer, buflen, errnop)); | |
298 | while (status == NSS_STATUS_SUCCESS && | |
299 | check_nonlocal_group("(unknown)", grp, &nonlocal_errno) != NSS_STATUS_SUCCESS); | |
300 | } | |
301 | if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) | |
302 | return status; | |
303 | ||
304 | if (status == NSS_STATUS_SUCCESS) | |
305 | return NSS_STATUS_SUCCESS; | |
306 | } while (__nss_next(&grent_nip, grent_fct_name, &grent_fct.ptr, status, 0) == 0); | |
307 | ||
308 | grent_nip = NULL; | |
309 | return NSS_STATUS_NOTFOUND; | |
310 | } | |
311 | ||
312 | ||
313 | enum nss_status | |
314 | _nss_nonlocal_getgrnam_r(const char *name, struct group *grp, | |
315 | char *buffer, size_t buflen, int *errnop) | |
316 | { | |
317 | static const char *fct_name = "getgrnam_r"; | |
318 | static void *fct_start = NULL; | |
319 | enum nss_status status; | |
320 | service_user *nip; | |
321 | union { | |
322 | enum nss_status (*l)(const char *name, struct group *grp, | |
323 | char *buffer, size_t buflen, int *errnop); | |
324 | void *ptr; | |
325 | } fct; | |
326 | ||
327 | char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV); | |
328 | if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0') | |
329 | return NSS_STATUS_UNAVAIL; | |
330 | ||
331 | nip = nss_group_nonlocal_database(); | |
332 | if (nip == NULL) | |
333 | return NSS_STATUS_UNAVAIL; | |
334 | if (fct_start == NULL) | |
335 | fct_start = __nss_lookup_function(nip, fct_name); | |
336 | fct.ptr = fct_start; | |
337 | do { | |
338 | if (fct.ptr == NULL) | |
339 | status = NSS_STATUS_UNAVAIL; | |
340 | else | |
341 | status = DL_CALL_FCT(fct.l, (name, grp, buffer, buflen, errnop)); | |
342 | if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) | |
343 | break; | |
344 | } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); | |
345 | if (status != NSS_STATUS_SUCCESS) | |
346 | return status; | |
347 | ||
348 | if (strcmp(name, grp->gr_name) != 0) { | |
349 | syslog(LOG_ERR, "nss_nonlocal: discarding group %s from lookup for group %s\n", grp->gr_name, name); | |
350 | return NSS_STATUS_NOTFOUND; | |
351 | } | |
352 | ||
353 | return check_nonlocal_group(name, grp, errnop); | |
354 | } | |
355 | ||
356 | enum nss_status | |
357 | _nss_nonlocal_getgrgid_r(gid_t gid, struct group *grp, | |
358 | char *buffer, size_t buflen, int *errnop) | |
359 | { | |
360 | static const char *fct_name = "getgrgid_r"; | |
361 | static void *fct_start = NULL; | |
362 | enum nss_status status; | |
363 | service_user *nip; | |
364 | union { | |
365 | enum nss_status (*l)(gid_t gid, struct group *grp, | |
366 | char *buffer, size_t buflen, int *errnop); | |
367 | void *ptr; | |
368 | } fct; | |
369 | ||
370 | char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV); | |
371 | if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0') | |
372 | return NSS_STATUS_UNAVAIL; | |
373 | ||
374 | nip = nss_group_nonlocal_database(); | |
375 | if (nip == NULL) | |
376 | return NSS_STATUS_UNAVAIL; | |
377 | if (fct_start == NULL) | |
378 | fct_start = __nss_lookup_function(nip, fct_name); | |
379 | fct.ptr = fct_start; | |
380 | do { | |
381 | if (fct.ptr == NULL) | |
382 | status = NSS_STATUS_UNAVAIL; | |
383 | else | |
384 | status = DL_CALL_FCT(fct.l, (gid, grp, buffer, buflen, errnop)); | |
385 | if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) | |
386 | break; | |
387 | } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); | |
388 | if (status != NSS_STATUS_SUCCESS) | |
389 | return status; | |
390 | ||
391 | if (gid != grp->gr_gid) { | |
392 | syslog(LOG_ERR, "nss_nonlocal: discarding gid %d from lookup for gid %d\n", grp->gr_gid, gid); | |
393 | return NSS_STATUS_NOTFOUND; | |
394 | } | |
395 | ||
396 | return check_nonlocal_group(grp->gr_name, grp, errnop); | |
397 | } | |
398 | ||
399 | enum nss_status | |
400 | _nss_nonlocal_initgroups_dyn(const char *user, gid_t group, long int *start, | |
401 | long int *size, gid_t **groupsp, long int limit, | |
402 | int *errnop) | |
403 | { | |
404 | static const char *fct_name = "initgroups_dyn"; | |
405 | static void *fct_start = NULL; | |
406 | enum nss_status status; | |
407 | service_user *nip; | |
408 | union { | |
409 | enum nss_status (*l)(const char *user, gid_t group, long int *start, | |
410 | long int *size, gid_t **groupsp, long int limit, | |
411 | int *errnop); | |
412 | void *ptr; | |
413 | } fct; | |
414 | ||
415 | struct group local_users_group, nonlocal_users_group; | |
416 | gid_t local_users_gid, gid; | |
417 | int is_local = 0; | |
418 | char *buffer; | |
419 | int old_errno; | |
420 | int in, out, i; | |
421 | ||
422 | /* Check that the user is a nonlocal user before adding any groups. */ | |
423 | status = check_nonlocal_user(user, errnop); | |
424 | if (status == NSS_STATUS_TRYAGAIN) | |
425 | return status; | |
426 | else if (status != NSS_STATUS_SUCCESS) | |
427 | is_local = 1; | |
428 | ||
429 | old_errno = errno; | |
430 | ||
431 | status = get_local_group(MAGIC_LOCAL_GROUPNAME, | |
432 | &local_users_group, &buffer, errnop); | |
433 | if (status == NSS_STATUS_SUCCESS) { | |
434 | local_users_gid = local_users_group.gr_gid; | |
435 | free(buffer); | |
436 | } else if (status == NSS_STATUS_TRYAGAIN) { | |
437 | return status; | |
438 | } else { | |
439 | syslog(LOG_WARNING, "nss_nonlocal: Group %s does not exist locally!", | |
440 | MAGIC_LOCAL_GROUPNAME); | |
441 | local_users_gid = -1; | |
442 | } | |
443 | ||
444 | if (is_local) { | |
445 | gid = local_users_gid; | |
446 | } else { | |
447 | status = get_local_group(MAGIC_NONLOCAL_GROUPNAME, | |
448 | &nonlocal_users_group, &buffer, errnop); | |
449 | if (status == NSS_STATUS_SUCCESS) { | |
450 | gid = nonlocal_users_group.gr_gid; | |
451 | free(buffer); | |
452 | } else if (status == NSS_STATUS_TRYAGAIN) { | |
453 | return status; | |
454 | } else { | |
455 | syslog(LOG_WARNING, "nss_nonlocal: Group %s does not exist locally!", | |
456 | MAGIC_NONLOCAL_GROUPNAME); | |
457 | gid = -1; | |
458 | } | |
459 | } | |
460 | ||
461 | if (gid != -1) { | |
462 | int i; | |
463 | for (i = 0; i < *start; ++i) | |
464 | if ((*groupsp)[i] == gid) | |
465 | break; | |
466 | if (i >= *start) { | |
467 | if (*start + 1 > *size) { | |
468 | gid_t *newgroups; | |
469 | long int newsize = 2 * *size; | |
470 | if (limit > 0) { | |
471 | if (*size >= limit) | |
472 | return NSS_STATUS_SUCCESS; | |
473 | if (newsize > limit) | |
474 | newsize = limit; | |
475 | } | |
476 | newgroups = realloc(*groupsp, newsize * sizeof((*groupsp)[0])); | |
477 | if (newgroups == NULL) { | |
478 | *errnop = ENOMEM; | |
479 | errno = old_errno; | |
480 | return NSS_STATUS_TRYAGAIN; | |
481 | } | |
482 | *groupsp = newgroups; | |
483 | *size = newsize; | |
484 | } | |
485 | (*groupsp)[(*start)++] = gid; | |
486 | } | |
487 | } | |
488 | ||
489 | if (is_local) | |
490 | return NSS_STATUS_SUCCESS; | |
491 | ||
492 | in = out = *start; | |
493 | ||
494 | nip = nss_group_nonlocal_database(); | |
495 | if (nip == NULL) | |
496 | return NSS_STATUS_UNAVAIL; | |
497 | if (fct_start == NULL) | |
498 | fct_start = __nss_lookup_function(nip, fct_name); | |
499 | fct.ptr = fct_start; | |
500 | ||
501 | do { | |
502 | if (fct.ptr == NULL) | |
503 | status = NSS_STATUS_UNAVAIL; | |
504 | else | |
505 | status = DL_CALL_FCT(fct.l, (user, group, start, size, groupsp, limit, errnop)); | |
506 | if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) | |
507 | break; | |
508 | } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); | |
509 | if (status != NSS_STATUS_SUCCESS) | |
510 | return status; | |
511 | ||
512 | for (; in < *start; ++in) { | |
513 | int nonlocal_errno = *errnop; | |
514 | ||
515 | for (i = 0; i < out; ++i) | |
516 | if ((*groupsp)[i] == (*groupsp)[in]) | |
517 | break; | |
518 | if (i < out) | |
519 | continue; | |
520 | ||
521 | /* Don't let users get into MAGIC_LOCAL_GROUPNAME from nonlocal reasons. */ | |
522 | if (local_users_gid == (*groupsp)[in]) { | |
523 | syslog(LOG_WARNING, "nss_nonlocal: Nonlocal user %s removed from special local users group %s", | |
524 | user, MAGIC_LOCAL_GROUPNAME); | |
525 | continue; | |
526 | } | |
527 | ||
528 | status = check_nonlocal_gid(user, (*groupsp)[in], &nonlocal_errno); | |
529 | if (status == NSS_STATUS_SUCCESS) { | |
530 | (*groupsp)[out++] = (*groupsp)[in]; | |
531 | } else if (status == NSS_STATUS_TRYAGAIN) { | |
532 | *start = out; | |
533 | *errnop = nonlocal_errno; | |
534 | return status; | |
535 | } | |
536 | } | |
537 | ||
538 | *start = out; | |
539 | return NSS_STATUS_SUCCESS; | |
540 | } |