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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 | /* | |
42 | * If the MAGIC_NONLOCAL_GROUPNAME local group exists, then nonlocal | |
43 | * users will be automatically added to it. Furthermore, if a local | |
44 | * user is added to this group, then that user will inherit any | |
45 | * nonlocal supplementary gids from a nonlocal user of the same name. | |
46 | */ | |
47 | #define MAGIC_NONLOCAL_GROUPNAME "nss-nonlocal-users" | |
48 | ||
49 | /* | |
50 | * If the MAGIC_LOCAL_GROUPNAME local group exists, then local users | |
51 | * will be automatically added to it. | |
52 | */ | |
53 | #define MAGIC_LOCAL_GROUPNAME "nss-local-users" | |
54 | ||
55 | ||
56 | enum nss_status | |
57 | _nss_nonlocal_getgrnam_r(const char *name, struct group *grp, | |
58 | char *buffer, size_t buflen, int *errnop); | |
59 | ||
60 | enum nss_status | |
61 | _nss_nonlocal_getgrgid_r(gid_t gid, struct group *grp, | |
62 | char *buffer, size_t buflen, int *errnop); | |
63 | ||
64 | ||
65 | static service_user *__nss_group_nonlocal_database; | |
66 | ||
67 | static int | |
68 | internal_function | |
69 | __nss_group_nonlocal_lookup(service_user **ni, const char *fct_name, | |
70 | void **fctp) | |
71 | { | |
72 | if (__nss_group_nonlocal_database == NULL | |
73 | && __nss_database_lookup("group_nonlocal", NULL, NULL, | |
74 | &__nss_group_nonlocal_database) < 0) | |
75 | return -1; | |
76 | ||
77 | *ni = __nss_group_nonlocal_database; | |
78 | ||
79 | *fctp = __nss_lookup_function(*ni, fct_name); | |
80 | return 0; | |
81 | } | |
82 | ||
83 | ||
84 | enum nss_status | |
85 | check_nonlocal_gid(const char *user, gid_t gid, int *errnop) | |
86 | { | |
87 | enum nss_status status; | |
88 | struct group gbuf; | |
89 | char *buf; | |
90 | size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX); | |
91 | const struct walk_nss w = { | |
92 | .lookup = &__nss_group_lookup, .fct_name = "getgrgid_r", | |
93 | .status = &status, .errnop = errnop, .buf = &buf, .buflen = &buflen | |
94 | }; | |
95 | const __typeof__(&_nss_nonlocal_getgrgid_r) self = &_nss_nonlocal_getgrgid_r; | |
96 | #define args (gid, &gbuf, buf, buflen, errnop) | |
97 | #include "walk_nss.h" | |
98 | #undef args | |
99 | ||
100 | if (status == NSS_STATUS_SUCCESS) { | |
101 | syslog(LOG_DEBUG, "nss_nonlocal: removing local group %u (%s) from non-local user %s\n", gbuf.gr_gid, gbuf.gr_name, user); | |
102 | free(buf); | |
103 | status = NSS_STATUS_NOTFOUND; | |
104 | } else if (status != NSS_STATUS_TRYAGAIN) { | |
105 | status = NSS_STATUS_SUCCESS; | |
106 | } | |
107 | ||
108 | return status; | |
109 | } | |
110 | ||
111 | enum nss_status | |
112 | check_nonlocal_group(const char *user, struct group *grp, int *errnop) | |
113 | { | |
114 | enum nss_status status = NSS_STATUS_SUCCESS; | |
115 | int old_errno = errno; | |
116 | char *end; | |
117 | unsigned long gid; | |
118 | ||
119 | errno = 0; | |
120 | gid = strtoul(grp->gr_name, &end, 10); | |
121 | if (errno == 0 && *end == '\0' && (gid_t)gid == gid) { | |
122 | errno = old_errno; | |
123 | status = check_nonlocal_gid(user, gid, errnop); | |
124 | } else | |
125 | errno = old_errno; | |
126 | if (status != NSS_STATUS_SUCCESS) | |
127 | return status; | |
128 | ||
129 | return check_nonlocal_gid(user, grp->gr_gid, errnop); | |
130 | } | |
131 | ||
132 | enum nss_status | |
133 | get_local_group(const char *name, struct group *grp, char **buffer, int *errnop) | |
134 | { | |
135 | enum nss_status status; | |
136 | size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX); | |
137 | const struct walk_nss w = { | |
138 | .lookup = &__nss_group_lookup, .fct_name = "getgrnam_r", | |
139 | .status = &status, .errnop = errnop, .buf = buffer, .buflen = &buflen | |
140 | }; | |
141 | const __typeof__(&_nss_nonlocal_getgrnam_r) self = &_nss_nonlocal_getgrnam_r; | |
142 | #define args (name, grp, *buffer, buflen, errnop) | |
143 | #include "walk_nss.h" | |
144 | #undef args | |
145 | return status; | |
146 | } | |
147 | ||
148 | static service_user *grent_startp, *grent_nip; | |
149 | static void *grent_fct_start; | |
150 | static union { | |
151 | enum nss_status (*l)(struct group *grp, char *buffer, size_t buflen, | |
152 | int *errnop); | |
153 | void *ptr; | |
154 | } grent_fct; | |
155 | static const char *grent_fct_name = "getgrent_r"; | |
156 | ||
157 | enum nss_status | |
158 | _nss_nonlocal_setgrent(int stayopen) | |
159 | { | |
160 | enum nss_status status; | |
161 | const struct walk_nss w = { | |
162 | .lookup = &__nss_group_nonlocal_lookup, .fct_name = "setgrent", | |
163 | .status = &status | |
164 | }; | |
165 | const __typeof__(&_nss_nonlocal_setgrent) self = NULL; | |
166 | #define args (stayopen) | |
167 | #include "walk_nss.h" | |
168 | #undef args | |
169 | if (status != NSS_STATUS_SUCCESS) | |
170 | return status; | |
171 | ||
172 | if (grent_fct_start == NULL) | |
173 | __nss_group_nonlocal_lookup(&grent_startp, grent_fct_name, | |
174 | &grent_fct_start); | |
175 | grent_nip = grent_startp; | |
176 | grent_fct.ptr = grent_fct_start; | |
177 | return NSS_STATUS_SUCCESS; | |
178 | } | |
179 | ||
180 | enum nss_status | |
181 | _nss_nonlocal_endgrent(void) | |
182 | { | |
183 | enum nss_status status; | |
184 | const struct walk_nss w = { | |
185 | .lookup = &__nss_group_nonlocal_lookup, .fct_name = "endgrent", | |
186 | .status = &status | |
187 | }; | |
188 | const __typeof__(&_nss_nonlocal_endgrent) self = NULL; | |
189 | ||
190 | grent_nip = NULL; | |
191 | ||
192 | #define args () | |
193 | #include "walk_nss.h" | |
194 | #undef args | |
195 | return status; | |
196 | } | |
197 | ||
198 | enum nss_status | |
199 | _nss_nonlocal_getgrent_r(struct group *grp, char *buffer, size_t buflen, | |
200 | int *errnop) | |
201 | { | |
202 | enum nss_status status; | |
203 | ||
204 | char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV); | |
205 | if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0') | |
206 | return NSS_STATUS_UNAVAIL; | |
207 | ||
208 | if (grent_nip == NULL) { | |
209 | status = _nss_nonlocal_setgrent(0); | |
210 | if (status != NSS_STATUS_SUCCESS) | |
211 | return status; | |
212 | } | |
213 | do { | |
214 | if (grent_fct.ptr == NULL) | |
215 | status = NSS_STATUS_UNAVAIL; | |
216 | else { | |
217 | int nonlocal_errno; | |
218 | do | |
219 | status = DL_CALL_FCT(grent_fct.l, (grp, buffer, buflen, errnop)); | |
220 | while (status == NSS_STATUS_SUCCESS && | |
221 | check_nonlocal_group("(unknown)", grp, &nonlocal_errno) != NSS_STATUS_SUCCESS); | |
222 | } | |
223 | if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) | |
224 | return status; | |
225 | ||
226 | if (status == NSS_STATUS_SUCCESS) | |
227 | return NSS_STATUS_SUCCESS; | |
228 | } while (__nss_next(&grent_nip, grent_fct_name, &grent_fct.ptr, status, 0) == 0); | |
229 | ||
230 | grent_nip = NULL; | |
231 | return NSS_STATUS_NOTFOUND; | |
232 | } | |
233 | ||
234 | ||
235 | enum nss_status | |
236 | _nss_nonlocal_getgrnam_r(const char *name, struct group *grp, | |
237 | char *buffer, size_t buflen, int *errnop) | |
238 | { | |
239 | enum nss_status status; | |
240 | const struct walk_nss w = { | |
241 | .lookup = &__nss_group_nonlocal_lookup, .fct_name = "getgrnam_r", | |
242 | .status = &status, .errnop = errnop | |
243 | }; | |
244 | const __typeof__(&_nss_nonlocal_getgrnam_r) self = NULL; | |
245 | ||
246 | char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV); | |
247 | if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0') | |
248 | return NSS_STATUS_UNAVAIL; | |
249 | ||
250 | #define args (name, grp, buffer, buflen, errnop) | |
251 | #include "walk_nss.h" | |
252 | #undef args | |
253 | if (status != NSS_STATUS_SUCCESS) | |
254 | return status; | |
255 | ||
256 | if (strcmp(name, grp->gr_name) != 0) { | |
257 | syslog(LOG_ERR, "nss_nonlocal: discarding group %s from lookup for group %s\n", grp->gr_name, name); | |
258 | return NSS_STATUS_NOTFOUND; | |
259 | } | |
260 | ||
261 | return check_nonlocal_group(name, grp, errnop); | |
262 | } | |
263 | ||
264 | enum nss_status | |
265 | _nss_nonlocal_getgrgid_r(gid_t gid, struct group *grp, | |
266 | char *buffer, size_t buflen, int *errnop) | |
267 | { | |
268 | enum nss_status status; | |
269 | const struct walk_nss w = { | |
270 | .lookup = &__nss_group_nonlocal_lookup, .fct_name = "getgrgid_r", | |
271 | .status = &status, .errnop = errnop | |
272 | }; | |
273 | const __typeof__(&_nss_nonlocal_getgrgid_r) self = NULL; | |
274 | ||
275 | char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV); | |
276 | if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0') | |
277 | return NSS_STATUS_UNAVAIL; | |
278 | ||
279 | #define args (gid, grp, buffer, buflen, errnop) | |
280 | #include "walk_nss.h" | |
281 | #undef args | |
282 | if (status != NSS_STATUS_SUCCESS) | |
283 | return status; | |
284 | ||
285 | if (gid != grp->gr_gid) { | |
286 | syslog(LOG_ERR, "nss_nonlocal: discarding gid %d from lookup for gid %d\n", grp->gr_gid, gid); | |
287 | return NSS_STATUS_NOTFOUND; | |
288 | } | |
289 | ||
290 | return check_nonlocal_group(grp->gr_name, grp, errnop); | |
291 | } | |
292 | ||
293 | static bool | |
294 | add_group(gid_t group, long int *start, long int *size, gid_t **groupsp, | |
295 | long int limit, int *errnop, enum nss_status *status) | |
296 | { | |
297 | int i, old_errno = errno; | |
298 | for (i = 0; i < *start; ++i) | |
299 | if ((*groupsp)[i] == group) | |
300 | return true; | |
301 | if (*start + 1 > *size) { | |
302 | gid_t *newgroups; | |
303 | long int newsize = 2 * *size; | |
304 | if (limit > 0) { | |
305 | if (*size >= limit) { | |
306 | *status = NSS_STATUS_SUCCESS; | |
307 | return false; | |
308 | } | |
309 | if (newsize > limit) | |
310 | newsize = limit; | |
311 | } | |
312 | newgroups = realloc(*groupsp, newsize * sizeof((*groupsp)[0])); | |
313 | errno = old_errno; | |
314 | if (newgroups == NULL) { | |
315 | *errnop = ENOMEM; | |
316 | *status = NSS_STATUS_TRYAGAIN; | |
317 | return false; | |
318 | } | |
319 | *groupsp = newgroups; | |
320 | *size = newsize; | |
321 | } | |
322 | (*groupsp)[(*start)++] = group; | |
323 | return true; | |
324 | } | |
325 | ||
326 | enum nss_status | |
327 | _nss_nonlocal_initgroups_dyn(const char *user, gid_t group, long int *start, | |
328 | long int *size, gid_t **groupsp, long int limit, | |
329 | int *errnop) | |
330 | { | |
331 | enum nss_status status; | |
332 | const struct walk_nss w = { | |
333 | .lookup = &__nss_group_nonlocal_lookup, .fct_name = "initgroups_dyn", | |
334 | .status = &status, .errnop = errnop | |
335 | }; | |
336 | const __typeof__(&_nss_nonlocal_initgroups_dyn) self = NULL; | |
337 | ||
338 | struct group local_users_group, nonlocal_users_group; | |
339 | bool is_nonlocal = true; | |
340 | char *buffer; | |
341 | int in, out, i; | |
342 | ||
343 | /* Check that the user is a nonlocal user, or a member of the | |
344 | * MAGIC_NONLOCAL_GROUPNAME group, before adding any groups. */ | |
345 | status = check_nonlocal_user(user, errnop); | |
346 | if (status == NSS_STATUS_TRYAGAIN) { | |
347 | return status; | |
348 | } else if (status != NSS_STATUS_SUCCESS) { | |
349 | is_nonlocal = false; | |
350 | ||
351 | status = get_local_group(MAGIC_LOCAL_GROUPNAME, | |
352 | &local_users_group, &buffer, errnop); | |
353 | if (status == NSS_STATUS_SUCCESS) { | |
354 | free(buffer); | |
355 | if (!add_group(local_users_group.gr_gid, start, size, groupsp, | |
356 | limit, errnop, &status)) | |
357 | return status; | |
358 | } else if (status == NSS_STATUS_TRYAGAIN) { | |
359 | return status; | |
360 | } else { | |
361 | syslog(LOG_WARNING, | |
362 | "nss_nonlocal: Group %s does not exist locally!", | |
363 | MAGIC_LOCAL_GROUPNAME); | |
364 | } | |
365 | } | |
366 | ||
367 | status = get_local_group(MAGIC_NONLOCAL_GROUPNAME, | |
368 | &nonlocal_users_group, &buffer, errnop); | |
369 | if (status == NSS_STATUS_SUCCESS) { | |
370 | free(buffer); | |
371 | if (is_nonlocal) { | |
372 | if (!add_group(nonlocal_users_group.gr_gid, start, size, groupsp, | |
373 | limit, errnop, &status)) | |
374 | return status; | |
375 | } else { | |
376 | int i; | |
377 | for (i = 0; i < *start; ++i) { | |
378 | if ((*groupsp)[i] == nonlocal_users_group.gr_gid) { | |
379 | is_nonlocal = true; | |
380 | break; | |
381 | } | |
382 | } | |
383 | } | |
384 | } else if (status == NSS_STATUS_TRYAGAIN) { | |
385 | if (is_nonlocal) | |
386 | return status; | |
387 | } else { | |
388 | syslog(LOG_WARNING, "nss_nonlocal: Group %s does not exist locally!", | |
389 | MAGIC_NONLOCAL_GROUPNAME); | |
390 | } | |
391 | ||
392 | if (!is_nonlocal) | |
393 | return NSS_STATUS_SUCCESS; | |
394 | ||
395 | in = out = *start; | |
396 | ||
397 | #define args (user, group, start, size, groupsp, limit, errnop) | |
398 | #include "walk_nss.h" | |
399 | #undef args | |
400 | if (status != NSS_STATUS_SUCCESS) | |
401 | return status; | |
402 | ||
403 | for (; in < *start; ++in) { | |
404 | int nonlocal_errno = *errnop; | |
405 | ||
406 | for (i = 0; i < out; ++i) | |
407 | if ((*groupsp)[i] == (*groupsp)[in]) | |
408 | break; | |
409 | if (i < out) | |
410 | continue; | |
411 | ||
412 | status = check_nonlocal_gid(user, (*groupsp)[in], &nonlocal_errno); | |
413 | if (status == NSS_STATUS_SUCCESS) { | |
414 | (*groupsp)[out++] = (*groupsp)[in]; | |
415 | } else if (status == NSS_STATUS_TRYAGAIN) { | |
416 | *start = out; | |
417 | *errnop = nonlocal_errno; | |
418 | return status; | |
419 | } | |
420 | } | |
421 | ||
422 | *start = out; | |
423 | return NSS_STATUS_SUCCESS; | |
424 | } |