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1 | /* | |
2 | * nonlocal-group.c | |
3 | * group database for nss_nonlocal proxy | |
4 | * | |
5 | * Copyright © 2007 Anders Kaseorg <andersk@mit.edu> and Tim Abbott | |
6 | * <tabbott@mit.edu> | |
7 | * | |
8 | * Permission is hereby granted, free of charge, to any person | |
9 | * obtaining a copy of this software and associated documentation | |
10 | * files (the "Software"), to deal in the Software without | |
11 | * restriction, including without limitation the rights to use, copy, | |
12 | * modify, merge, publish, distribute, sublicense, and/or sell copies | |
13 | * of the Software, and to permit persons to whom the Software is | |
14 | * furnished to do so, subject to the following conditions: | |
15 | * | |
16 | * The above copyright notice and this permission notice shall be | |
17 | * included in all copies or substantial portions of the Software. | |
18 | * | |
19 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, | |
20 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF | |
21 | * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND | |
22 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS | |
23 | * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN | |
24 | * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN | |
25 | * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
26 | * SOFTWARE. | |
27 | */ | |
28 | ||
29 | #define _GNU_SOURCE | |
30 | #include <sys/types.h> | |
31 | #include <unistd.h> | |
32 | #include <stdlib.h> | |
33 | #include <stdint.h> | |
34 | #include <string.h> | |
35 | #include <dlfcn.h> | |
36 | #include <stdio.h> | |
37 | #include <syslog.h> | |
38 | #include <errno.h> | |
39 | #include <grp.h> | |
40 | #include <nss.h> | |
41 | #include "nsswitch-internal.h" | |
42 | #include "nonlocal.h" | |
43 | ||
44 | #define MAGIC_NONLOCAL_GROUPNAME "nss-nonlocal-users" | |
45 | #define MAGIC_LOCAL_GROUPNAME "nss-local-users" | |
46 | ||
47 | ||
48 | enum nss_status | |
49 | _nss_nonlocal_getgrnam_r(const char *name, struct group *grp, | |
50 | char *buffer, size_t buflen, int *errnop); | |
51 | ||
52 | enum nss_status | |
53 | _nss_nonlocal_getgrgid_r(gid_t gid, struct group *grp, | |
54 | char *buffer, size_t buflen, int *errnop); | |
55 | ||
56 | ||
57 | static service_user * | |
58 | nss_group_nonlocal_database(void) | |
59 | { | |
60 | static service_user *nip = NULL; | |
61 | if (nip == NULL) | |
62 | __nss_database_lookup("group_nonlocal", NULL, "", &nip); | |
63 | ||
64 | return nip; | |
65 | } | |
66 | ||
67 | ||
68 | enum nss_status | |
69 | check_nonlocal_gid(const char *user, gid_t gid, int *errnop) | |
70 | { | |
71 | static const char *fct_name = "getgrgid_r"; | |
72 | static service_user *startp = NULL; | |
73 | static void *fct_start = NULL; | |
74 | enum nss_status status; | |
75 | service_user *nip; | |
76 | union { | |
77 | enum nss_status (*l)(gid_t gid, struct group *grp, | |
78 | char *buffer, size_t buflen, int *errnop); | |
79 | void *ptr; | |
80 | } fct; | |
81 | struct group gbuf; | |
82 | int old_errno = errno; | |
83 | ||
84 | int buflen = sysconf(_SC_GETGR_R_SIZE_MAX); | |
85 | char *buf = malloc(buflen); | |
86 | if (buf == NULL) { | |
87 | *errnop = ENOMEM; | |
88 | errno = old_errno; | |
89 | return NSS_STATUS_TRYAGAIN; | |
90 | } | |
91 | ||
92 | if (fct_start == NULL && | |
93 | __nss_group_lookup(&startp, fct_name, &fct_start) != 0) { | |
94 | free(buf); | |
95 | return NSS_STATUS_UNAVAIL; | |
96 | } | |
97 | nip = startp; | |
98 | fct.ptr = fct_start; | |
99 | do { | |
100 | if (fct.l == _nss_nonlocal_getgrgid_r) | |
101 | status = NSS_STATUS_NOTFOUND; | |
102 | else | |
103 | status = DL_CALL_FCT(fct.l, (gid, &gbuf, buf, buflen, errnop)); | |
104 | if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) | |
105 | break; | |
106 | } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); | |
107 | ||
108 | if (status == NSS_STATUS_SUCCESS) { | |
109 | syslog(LOG_WARNING, "nss_nonlocal: removing local group %u (%s) from non-local user %s\n", gbuf.gr_gid, gbuf.gr_name, user); | |
110 | status = NSS_STATUS_NOTFOUND; | |
111 | } else if (status != NSS_STATUS_TRYAGAIN) { | |
112 | status = NSS_STATUS_SUCCESS; | |
113 | } | |
114 | ||
115 | free(buf); | |
116 | return status; | |
117 | } | |
118 | ||
119 | enum nss_status | |
120 | get_local_group(const char *name, struct group *grp, char *buffer, size_t buflen, int *errnop) | |
121 | { | |
122 | static const char *fct_name = "getgrnam_r"; | |
123 | static service_user *startp = NULL; | |
124 | static void *fct_start = NULL; | |
125 | enum nss_status status; | |
126 | service_user *nip; | |
127 | union { | |
128 | enum nss_status (*l)(const char *name, struct group *grp, | |
129 | char *buffer, size_t buflen, int *errnop); | |
130 | void *ptr; | |
131 | } fct; | |
132 | struct group gbuf; | |
133 | int n; | |
134 | int old_errno = errno; | |
135 | ||
136 | int len = sysconf(_SC_GETGR_R_SIZE_MAX); | |
137 | char *buf = malloc(len); | |
138 | if (buf == NULL) { | |
139 | *errnop = ENOMEM; | |
140 | errno = old_errno; | |
141 | return NSS_STATUS_TRYAGAIN; | |
142 | } | |
143 | ||
144 | if (fct_start == NULL && | |
145 | __nss_group_lookup(&startp, fct_name, &fct_start) != 0) { | |
146 | free(buf); | |
147 | return NSS_STATUS_UNAVAIL; | |
148 | } | |
149 | nip = startp; | |
150 | fct.ptr = fct_start; | |
151 | do { | |
152 | if (fct.l == _nss_nonlocal_getgrnam_r) | |
153 | status = NSS_STATUS_NOTFOUND; | |
154 | else | |
155 | status = DL_CALL_FCT(fct.l, (name, &gbuf, buf, buflen, errnop)); | |
156 | if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) | |
157 | break; | |
158 | } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); | |
159 | ||
160 | if (status != NSS_STATUS_SUCCESS) | |
161 | goto get_local_group_done; | |
162 | ||
163 | n = snprintf(buffer, buflen, "%s", gbuf.gr_name); | |
164 | if (n < 0 || n >= buflen) { | |
165 | *errnop = ERANGE; | |
166 | status = NSS_STATUS_TRYAGAIN; | |
167 | goto get_local_group_done; | |
168 | } | |
169 | grp->gr_name = buffer; | |
170 | buffer += n; | |
171 | buflen -= n; | |
172 | ||
173 | n = snprintf(buffer, buflen, "%s", gbuf.gr_passwd); | |
174 | if (n < 0 || n >= buflen) { | |
175 | *errnop = ERANGE; | |
176 | status = NSS_STATUS_TRYAGAIN; | |
177 | goto get_local_group_done; | |
178 | } | |
179 | grp->gr_passwd = buffer; | |
180 | buffer += n; | |
181 | buflen -= n; | |
182 | ||
183 | grp->gr_gid = gbuf.gr_gid; | |
184 | ||
185 | if (buflen < sizeof(void *)) { | |
186 | *errnop = ERANGE; | |
187 | status = NSS_STATUS_TRYAGAIN; | |
188 | goto get_local_group_done; | |
189 | } | |
190 | *(void **)buffer = NULL; | |
191 | buffer += sizeof(void *); | |
192 | buflen -= sizeof(void *); | |
193 | ||
194 | get_local_group_done: | |
195 | free(buf); | |
196 | return status; | |
197 | } | |
198 | ||
199 | static service_user *grent_nip = NULL; | |
200 | static void *grent_fct_start; | |
201 | static union { | |
202 | enum nss_status (*l)(struct group *grp, char *buffer, size_t buflen, | |
203 | int *errnop); | |
204 | void *ptr; | |
205 | } grent_fct; | |
206 | static const char *grent_fct_name = "getgrent_r"; | |
207 | ||
208 | enum nss_status | |
209 | _nss_nonlocal_setgrent(int stayopen) | |
210 | { | |
211 | static const char *fct_name = "setgrent"; | |
212 | static void *fct_start = NULL; | |
213 | enum nss_status status; | |
214 | service_user *nip; | |
215 | union { | |
216 | enum nss_status (*l)(int stayopen); | |
217 | void *ptr; | |
218 | } fct; | |
219 | ||
220 | nip = nss_group_nonlocal_database(); | |
221 | if (nip == NULL) | |
222 | return NSS_STATUS_UNAVAIL; | |
223 | if (fct_start == NULL) | |
224 | fct_start = __nss_lookup_function(nip, fct_name); | |
225 | fct.ptr = fct_start; | |
226 | do { | |
227 | if (fct.ptr == NULL) | |
228 | status = NSS_STATUS_UNAVAIL; | |
229 | else | |
230 | status = DL_CALL_FCT(fct.l, (stayopen)); | |
231 | } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); | |
232 | if (status != NSS_STATUS_SUCCESS) | |
233 | return status; | |
234 | ||
235 | grent_nip = nip; | |
236 | if (grent_fct_start == NULL) | |
237 | grent_fct_start = __nss_lookup_function(nip, grent_fct_name); | |
238 | grent_fct.ptr = grent_fct_start; | |
239 | return NSS_STATUS_SUCCESS; | |
240 | } | |
241 | ||
242 | enum nss_status | |
243 | _nss_nonlocal_endgrent(void) | |
244 | { | |
245 | static const char *fct_name = "endgrent"; | |
246 | static void *fct_start = NULL; | |
247 | enum nss_status status; | |
248 | service_user *nip; | |
249 | union { | |
250 | enum nss_status (*l)(void); | |
251 | void *ptr; | |
252 | } fct; | |
253 | ||
254 | grent_nip = NULL; | |
255 | ||
256 | nip = nss_group_nonlocal_database(); | |
257 | if (nip == NULL) | |
258 | return NSS_STATUS_UNAVAIL; | |
259 | if (fct_start == NULL) | |
260 | fct_start = __nss_lookup_function(nip, fct_name); | |
261 | fct.ptr = fct_start; | |
262 | do { | |
263 | if (fct.ptr == NULL) | |
264 | status = NSS_STATUS_UNAVAIL; | |
265 | else | |
266 | status = DL_CALL_FCT(fct.l, ()); | |
267 | } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); | |
268 | return status; | |
269 | } | |
270 | ||
271 | enum nss_status | |
272 | _nss_nonlocal_getgrent_r(struct group *grp, char *buffer, size_t buflen, | |
273 | int *errnop) | |
274 | { | |
275 | enum nss_status status; | |
276 | ||
277 | char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV); | |
278 | if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0') | |
279 | return NSS_STATUS_UNAVAIL; | |
280 | ||
281 | if (grent_nip == NULL) { | |
282 | status = _nss_nonlocal_setgrent(0); | |
283 | if (status != NSS_STATUS_SUCCESS) | |
284 | return status; | |
285 | } | |
286 | do { | |
287 | if (grent_fct.ptr == NULL) | |
288 | status = NSS_STATUS_UNAVAIL; | |
289 | else { | |
290 | int nonlocal_errno; | |
291 | do | |
292 | status = DL_CALL_FCT(grent_fct.l, (grp, buffer, buflen, errnop)); | |
293 | while (status == NSS_STATUS_SUCCESS && | |
294 | check_nonlocal_gid("(unknown)", grp->gr_gid, &nonlocal_errno) != NSS_STATUS_SUCCESS); | |
295 | } | |
296 | if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) | |
297 | return status; | |
298 | ||
299 | if (status == NSS_STATUS_SUCCESS) | |
300 | return NSS_STATUS_SUCCESS; | |
301 | } while (__nss_next(&grent_nip, grent_fct_name, &grent_fct.ptr, status, 0) == 0); | |
302 | ||
303 | grent_nip = NULL; | |
304 | return NSS_STATUS_NOTFOUND; | |
305 | } | |
306 | ||
307 | ||
308 | enum nss_status | |
309 | _nss_nonlocal_getgrnam_r(const char *name, struct group *grp, | |
310 | char *buffer, size_t buflen, int *errnop) | |
311 | { | |
312 | static const char *fct_name = "getgrnam_r"; | |
313 | static void *fct_start = NULL; | |
314 | enum nss_status status; | |
315 | service_user *nip; | |
316 | union { | |
317 | enum nss_status (*l)(const char *name, struct group *grp, | |
318 | char *buffer, size_t buflen, int *errnop); | |
319 | void *ptr; | |
320 | } fct; | |
321 | ||
322 | char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV); | |
323 | if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0') | |
324 | return NSS_STATUS_UNAVAIL; | |
325 | ||
326 | nip = nss_group_nonlocal_database(); | |
327 | if (nip == NULL) | |
328 | return NSS_STATUS_UNAVAIL; | |
329 | if (fct_start == NULL) | |
330 | fct_start = __nss_lookup_function(nip, fct_name); | |
331 | fct.ptr = fct_start; | |
332 | do { | |
333 | if (fct.ptr == NULL) | |
334 | status = NSS_STATUS_UNAVAIL; | |
335 | else | |
336 | status = DL_CALL_FCT(fct.l, (name, grp, buffer, buflen, errnop)); | |
337 | if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) | |
338 | break; | |
339 | } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); | |
340 | if (status != NSS_STATUS_SUCCESS) | |
341 | return status; | |
342 | ||
343 | return check_nonlocal_gid(name, grp->gr_gid, errnop); | |
344 | } | |
345 | ||
346 | enum nss_status | |
347 | _nss_nonlocal_getgrgid_r(gid_t gid, struct group *grp, | |
348 | char *buffer, size_t buflen, int *errnop) | |
349 | { | |
350 | static const char *fct_name = "getgrgid_r"; | |
351 | static void *fct_start = NULL; | |
352 | enum nss_status status; | |
353 | service_user *nip; | |
354 | union { | |
355 | enum nss_status (*l)(gid_t gid, struct group *grp, | |
356 | char *buffer, size_t buflen, int *errnop); | |
357 | void *ptr; | |
358 | } fct; | |
359 | ||
360 | char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV); | |
361 | if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0') | |
362 | return NSS_STATUS_UNAVAIL; | |
363 | ||
364 | nip = nss_group_nonlocal_database(); | |
365 | if (nip == NULL) | |
366 | return NSS_STATUS_UNAVAIL; | |
367 | if (fct_start == NULL) | |
368 | fct_start = __nss_lookup_function(nip, fct_name); | |
369 | fct.ptr = fct_start; | |
370 | do { | |
371 | if (fct.ptr == NULL) | |
372 | status = NSS_STATUS_UNAVAIL; | |
373 | else | |
374 | status = DL_CALL_FCT(fct.l, (gid, grp, buffer, buflen, errnop)); | |
375 | if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) | |
376 | break; | |
377 | } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); | |
378 | if (status != NSS_STATUS_SUCCESS) | |
379 | return status; | |
380 | ||
381 | return check_nonlocal_gid(grp->gr_name, grp->gr_gid, errnop); | |
382 | } | |
383 | ||
384 | enum nss_status | |
385 | _nss_nonlocal_initgroups_dyn(const char *user, gid_t group, long int *start, | |
386 | long int *size, gid_t **groupsp, long int limit, | |
387 | int *errnop) | |
388 | { | |
389 | static const char *fct_name = "initgroups_dyn"; | |
390 | static void *fct_start = NULL; | |
391 | enum nss_status status; | |
392 | service_user *nip; | |
393 | union { | |
394 | enum nss_status (*l)(const char *user, gid_t group, long int *start, | |
395 | long int *size, gid_t **groupsp, long int limit, | |
396 | int *errnop); | |
397 | void *ptr; | |
398 | } fct; | |
399 | ||
400 | struct group local_users_group, nonlocal_users_group; | |
401 | gid_t local_users_gid, gid; | |
402 | int is_local = 0; | |
403 | int buflen; | |
404 | char *buffer; | |
405 | ||
406 | /* Check that the user is a nonlocal user before adding any groups. */ | |
407 | status = check_nonlocal_user(user, errnop); | |
408 | if (status == NSS_STATUS_TRYAGAIN) | |
409 | return status; | |
410 | else if (status != NSS_STATUS_SUCCESS) | |
411 | is_local = 1; | |
412 | ||
413 | int old_errno = errno; | |
414 | ||
415 | buflen = sysconf(_SC_GETGR_R_SIZE_MAX); | |
416 | buffer = malloc(buflen); | |
417 | if (buffer == NULL) { | |
418 | *errnop = ENOMEM; | |
419 | errno = old_errno; | |
420 | return NSS_STATUS_TRYAGAIN; | |
421 | } | |
422 | status = get_local_group(MAGIC_LOCAL_GROUPNAME, | |
423 | &local_users_group, buffer, buflen, errnop); | |
424 | if (status == NSS_STATUS_SUCCESS) { | |
425 | local_users_gid = local_users_group.gr_gid; | |
426 | } else if (status == NSS_STATUS_TRYAGAIN) { | |
427 | free(buffer); | |
428 | return status; | |
429 | } else { | |
430 | syslog(LOG_WARNING, "nss_nonlocal: Group %s does not exist locally!", | |
431 | MAGIC_LOCAL_GROUPNAME); | |
432 | local_users_gid = -1; | |
433 | } | |
434 | free(buffer); | |
435 | ||
436 | if (is_local) { | |
437 | gid = local_users_gid; | |
438 | } else { | |
439 | buflen = sysconf(_SC_GETGR_R_SIZE_MAX); | |
440 | buffer = malloc(buflen); | |
441 | if (buffer == NULL) { | |
442 | *errnop = ENOMEM; | |
443 | errno = old_errno; | |
444 | return NSS_STATUS_TRYAGAIN; | |
445 | } | |
446 | status = get_local_group(MAGIC_NONLOCAL_GROUPNAME, | |
447 | &nonlocal_users_group, buffer, buflen, errnop); | |
448 | if (status == NSS_STATUS_SUCCESS) { | |
449 | gid = nonlocal_users_group.gr_gid; | |
450 | } else if (status == NSS_STATUS_TRYAGAIN) { | |
451 | free(buffer); | |
452 | return status; | |
453 | } else { | |
454 | syslog(LOG_WARNING, "nss_nonlocal: Group %s does not exist locally!", | |
455 | MAGIC_NONLOCAL_GROUPNAME); | |
456 | gid = -1; | |
457 | } | |
458 | free(buffer); | |
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 | int in = *start, out = *start, i; | |
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 | } |