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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> | |
6 | * | |
7 | * Permission is hereby granted, free of charge, to any person | |
8 | * obtaining a copy of this software and associated documentation | |
9 | * files (the "Software"), to deal in the Software without | |
10 | * restriction, including without limitation the rights to use, copy, | |
11 | * modify, merge, publish, distribute, sublicense, and/or sell copies | |
12 | * of the Software, and to permit persons to whom the Software is | |
13 | * furnished to do so, subject to the following conditions: | |
14 | * | |
15 | * The above copyright notice and this permission notice shall be | |
16 | * included in all copies or substantial portions of the Software. | |
17 | * | |
18 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, | |
19 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF | |
20 | * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND | |
21 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS | |
22 | * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN | |
23 | * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN | |
24 | * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
25 | * SOFTWARE. | |
26 | */ | |
27 | ||
28 | #define _GNU_SOURCE | |
29 | #include <sys/types.h> | |
30 | #include <unistd.h> | |
31 | #include <stdlib.h> | |
32 | #include <stdint.h> | |
33 | #include <string.h> | |
34 | #include <dlfcn.h> | |
35 | #include <stdio.h> | |
36 | #include <syslog.h> | |
37 | #include <errno.h> | |
38 | #include <grp.h> | |
39 | #include <nss.h> | |
40 | #include "nsswitch-internal.h" | |
41 | #include "nonlocal.h" | |
42 | ||
43 | ||
44 | static service_user * | |
45 | nss_group_nonlocal_database(void) | |
46 | { | |
47 | static service_user *nip = NULL; | |
48 | if (nip == NULL) | |
49 | __nss_database_lookup("group_nonlocal", NULL, "", &nip); | |
50 | ||
51 | return nip; | |
52 | } | |
53 | ||
54 | ||
55 | static __thread int local_only = 0; | |
56 | ||
57 | enum nss_status | |
58 | local_getgrgid_r(gid_t gid, struct group *grp, | |
59 | char *buffer, size_t buflen, int *errnop) | |
60 | { | |
61 | int old_local_only = local_only; | |
62 | int old_errno = errno; | |
63 | int ret; | |
64 | errno = *errnop; | |
65 | local_only = 1; | |
66 | ||
67 | ret = getgrgid_r(gid, grp, buffer, buflen, &grp); | |
68 | ||
69 | local_only = old_local_only; | |
70 | *errnop = errno; | |
71 | errno = old_errno; | |
72 | ||
73 | if (grp != NULL) | |
74 | return NSS_STATUS_SUCCESS; | |
75 | else if (ret == 0) | |
76 | return NSS_STATUS_NOTFOUND; | |
77 | else | |
78 | return NSS_STATUS_TRYAGAIN; | |
79 | } | |
80 | ||
81 | enum nss_status | |
82 | check_nonlocal_gid(const char *user, gid_t gid, int *errnop) | |
83 | { | |
84 | struct group local_grp; | |
85 | int local_errno = errno; | |
86 | enum nss_status local_status, status = NSS_STATUS_SUCCESS; | |
87 | int local_buflen = sysconf(_SC_GETGR_R_SIZE_MAX); | |
88 | char *local_buffer = malloc(local_buflen); | |
89 | if (local_buffer == NULL) { | |
90 | *errnop = ENOMEM; | |
91 | errno = local_errno; | |
92 | return NSS_STATUS_TRYAGAIN; | |
93 | } | |
94 | local_errno = 0; | |
95 | local_status = local_getgrgid_r(gid, &local_grp, local_buffer, | |
96 | local_buflen, &local_errno); | |
97 | if (local_status == NSS_STATUS_SUCCESS) { | |
98 | syslog(LOG_WARNING, "nss_nonlocal: removing local group %u (%s) from non-local user %s\n", local_grp.gr_gid, local_grp.gr_name, user); | |
99 | status = NSS_STATUS_NOTFOUND; | |
100 | } else if (local_status != NSS_STATUS_NOTFOUND && | |
101 | local_status != NSS_STATUS_UNAVAIL) { | |
102 | *errnop = local_errno; | |
103 | status = local_status; | |
104 | } | |
105 | free(local_buffer); | |
106 | return status; | |
107 | } | |
108 | ||
109 | ||
110 | static service_user *grent_nip = NULL; | |
111 | static void *grent_fct_start; | |
112 | static union { | |
113 | enum nss_status (*l)(struct group *grp, char *buffer, size_t buflen, | |
114 | int *errnop); | |
115 | void *ptr; | |
116 | } grent_fct; | |
117 | static const char *grent_fct_name = "getgrent_r"; | |
118 | ||
119 | enum nss_status | |
120 | _nss_nonlocal_setgrent(int stayopen) | |
121 | { | |
122 | static const char *fct_name = "setgrent"; | |
123 | static void *fct_start = NULL; | |
124 | enum nss_status status; | |
125 | service_user *nip; | |
126 | union { | |
127 | enum nss_status (*l)(int stayopen); | |
128 | void *ptr; | |
129 | } fct; | |
130 | ||
131 | nip = nss_group_nonlocal_database(); | |
132 | if (nip == NULL) | |
133 | return NSS_STATUS_UNAVAIL; | |
134 | if (fct_start == NULL) | |
135 | fct_start = __nss_lookup_function(nip, fct_name); | |
136 | fct.ptr = fct_start; | |
137 | do { | |
138 | if (fct.ptr == NULL) | |
139 | status = NSS_STATUS_UNAVAIL; | |
140 | else | |
141 | status = DL_CALL_FCT(fct.l, (stayopen)); | |
142 | } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); | |
143 | if (status != NSS_STATUS_SUCCESS) | |
144 | return status; | |
145 | ||
146 | grent_nip = nip; | |
147 | if (grent_fct_start == NULL) | |
148 | grent_fct_start = __nss_lookup_function(nip, grent_fct_name); | |
149 | grent_fct.ptr = grent_fct_start; | |
150 | return NSS_STATUS_SUCCESS; | |
151 | } | |
152 | ||
153 | enum nss_status | |
154 | _nss_nonlocal_endgrent(void) | |
155 | { | |
156 | static const char *fct_name = "endgrent"; | |
157 | static void *fct_start = NULL; | |
158 | enum nss_status status; | |
159 | service_user *nip; | |
160 | union { | |
161 | enum nss_status (*l)(void); | |
162 | void *ptr; | |
163 | } fct; | |
164 | ||
165 | grent_nip = NULL; | |
166 | ||
167 | nip = nss_group_nonlocal_database(); | |
168 | if (nip == NULL) | |
169 | return NSS_STATUS_UNAVAIL; | |
170 | if (fct_start == NULL) | |
171 | fct_start = __nss_lookup_function(nip, fct_name); | |
172 | fct.ptr = fct_start; | |
173 | do { | |
174 | if (fct.ptr == NULL) | |
175 | status = NSS_STATUS_UNAVAIL; | |
176 | else | |
177 | status = DL_CALL_FCT(fct.l, ()); | |
178 | } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); | |
179 | return status; | |
180 | } | |
181 | ||
182 | enum nss_status | |
183 | _nss_nonlocal_getgrent_r(struct group *grp, char *buffer, size_t buflen, | |
184 | int *errnop) | |
185 | { | |
186 | enum nss_status status; | |
187 | if (grent_nip == NULL) { | |
188 | status = _nss_nonlocal_setgrent(0); | |
189 | if (status != NSS_STATUS_SUCCESS) | |
190 | return status; | |
191 | } | |
192 | do { | |
193 | if (grent_fct.ptr == NULL) | |
194 | status = NSS_STATUS_UNAVAIL; | |
195 | else { | |
196 | int nonlocal_errno; | |
197 | do | |
198 | status = DL_CALL_FCT(grent_fct.l, (grp, buffer, buflen, errnop)); | |
199 | while (status == NSS_STATUS_SUCCESS && | |
200 | check_nonlocal_gid("(unknown)", grp->gr_gid, &nonlocal_errno) != NSS_STATUS_SUCCESS); | |
201 | } | |
202 | if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) | |
203 | return status; | |
204 | ||
205 | if (status == NSS_STATUS_SUCCESS) | |
206 | return NSS_STATUS_SUCCESS; | |
207 | } while (__nss_next(&grent_nip, grent_fct_name, &grent_fct.ptr, status, 0) == 0); | |
208 | ||
209 | grent_nip = NULL; | |
210 | return NSS_STATUS_NOTFOUND; | |
211 | } | |
212 | ||
213 | ||
214 | enum nss_status | |
215 | _nss_nonlocal_getgrnam_r(const char *name, struct group *grp, | |
216 | char *buffer, size_t buflen, int *errnop) | |
217 | { | |
218 | static const char *fct_name = "getgrnam_r"; | |
219 | static void *fct_start = NULL; | |
220 | enum nss_status status; | |
221 | service_user *nip; | |
222 | union { | |
223 | enum nss_status (*l)(const char *name, struct group *grp, | |
224 | char *buffer, size_t buflen, int *errnop); | |
225 | void *ptr; | |
226 | } fct; | |
227 | ||
228 | nip = nss_group_nonlocal_database(); | |
229 | if (nip == NULL) | |
230 | return NSS_STATUS_UNAVAIL; | |
231 | if (fct_start == NULL) | |
232 | fct_start = __nss_lookup_function(nip, fct_name); | |
233 | fct.ptr = fct_start; | |
234 | do { | |
235 | if (fct.ptr == NULL) | |
236 | status = NSS_STATUS_UNAVAIL; | |
237 | else | |
238 | status = DL_CALL_FCT(fct.l, (name, grp, buffer, buflen, errnop)); | |
239 | if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) | |
240 | break; | |
241 | } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); | |
242 | if (status != NSS_STATUS_SUCCESS) | |
243 | return status; | |
244 | ||
245 | return check_nonlocal_gid(name, grp->gr_gid, errnop); | |
246 | } | |
247 | ||
248 | enum nss_status | |
249 | _nss_nonlocal_getgrgid_r(gid_t gid, struct group *grp, | |
250 | char *buffer, size_t buflen, int *errnop) | |
251 | { | |
252 | static const char *fct_name = "getgrgid_r"; | |
253 | static void *fct_start = NULL; | |
254 | enum nss_status status; | |
255 | service_user *nip; | |
256 | union { | |
257 | enum nss_status (*l)(gid_t gid, struct group *grp, | |
258 | char *buffer, size_t buflen, int *errnop); | |
259 | void *ptr; | |
260 | } fct; | |
261 | ||
262 | if (local_only == 1) | |
263 | return NSS_STATUS_UNAVAIL; | |
264 | ||
265 | nip = nss_group_nonlocal_database(); | |
266 | if (nip == NULL) | |
267 | return NSS_STATUS_UNAVAIL; | |
268 | if (fct_start == NULL) | |
269 | fct_start = __nss_lookup_function(nip, fct_name); | |
270 | fct.ptr = fct_start; | |
271 | do { | |
272 | if (fct.ptr == NULL) | |
273 | status = NSS_STATUS_UNAVAIL; | |
274 | else | |
275 | status = DL_CALL_FCT(fct.l, (gid, grp, buffer, buflen, errnop)); | |
276 | if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) | |
277 | break; | |
278 | } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); | |
279 | if (status != NSS_STATUS_SUCCESS) | |
280 | return status; | |
281 | ||
282 | return check_nonlocal_gid(grp->gr_name, grp->gr_gid, errnop); | |
283 | } | |
284 | ||
285 | enum nss_status | |
286 | _nss_nonlocal_initgroups_dyn(const char *user, gid_t group, long int *start, | |
287 | long int *size, gid_t **groupsp, long int limit, | |
288 | int *errnop) | |
289 | { | |
290 | static const char *fct_name = "initgroups_dyn"; | |
291 | static void *fct_start = NULL; | |
292 | enum nss_status status; | |
293 | service_user *nip; | |
294 | union { | |
295 | enum nss_status (*l)(const char *user, gid_t group, long int *start, | |
296 | long int *size, gid_t **groupsp, long int limit, | |
297 | int *errnop); | |
298 | void *ptr; | |
299 | } fct; | |
300 | int in = *start, out = *start, i; | |
301 | ||
302 | nip = nss_group_nonlocal_database(); | |
303 | if (nip == NULL) | |
304 | return NSS_STATUS_UNAVAIL; | |
305 | if (fct_start == NULL) | |
306 | fct_start = __nss_lookup_function(nip, fct_name); | |
307 | fct.ptr = fct_start; | |
308 | ||
309 | do { | |
310 | if (fct.ptr == NULL) | |
311 | status = NSS_STATUS_UNAVAIL; | |
312 | else | |
313 | status = DL_CALL_FCT(fct.l, (user, group, start, size, groupsp, limit, errnop)); | |
314 | if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) | |
315 | break; | |
316 | } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); | |
317 | if (status != NSS_STATUS_SUCCESS) | |
318 | return status; | |
319 | ||
320 | for (; in < *start; ++in) { | |
321 | int nonlocal_errno = *errnop; | |
322 | ||
323 | for (i = 0; i < out; ++i) | |
324 | if ((*groupsp)[i] == (*groupsp)[in]) | |
325 | break; | |
326 | if (i < out) | |
327 | continue; | |
328 | ||
329 | status = check_nonlocal_gid(user, (*groupsp)[in], &nonlocal_errno); | |
330 | if (status == NSS_STATUS_SUCCESS) { | |
331 | (*groupsp)[out++] = (*groupsp)[in]; | |
332 | } else if (status != NSS_STATUS_NOTFOUND) { | |
333 | *start = out; | |
334 | *errnop = nonlocal_errno; | |
335 | return status; | |
336 | } | |
337 | } | |
338 | ||
339 | *start = out; | |
340 | return NSS_STATUS_SUCCESS; | |
341 | } |