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1/*
2 * nonlocal-group.c
3 * group database for nss_nonlocal proxy
4 *
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5 * Copyright © 2007 Anders Kaseorg <andersk@mit.edu> and Tim Abbott
6 * <tabbott@mit.edu>
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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
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44#define MAGIC_NONLOCAL_GROUPNAME "nss-nonlocal-users"
45#define MAGIC_LOCAL_GROUPNAME "nss-local-users"
f7293a54 46
f6903667 47
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48enum nss_status
49_nss_nonlocal_getgrnam_r(const char *name, struct group *grp,
50 char *buffer, size_t buflen, int *errnop);
51
52enum nss_status
53_nss_nonlocal_getgrgid_r(gid_t gid, struct group *grp,
54 char *buffer, size_t buflen, int *errnop);
55
56
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57static service_user *
58nss_group_nonlocal_database(void)
59{
60 static service_user *nip = NULL;
61 if (nip == NULL)
62 __nss_database_lookup("group_nonlocal", NULL, "", &nip);
48479fc7 63
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64 return nip;
65}
66
67
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68enum nss_status
69check_nonlocal_gid(const char *user, gid_t gid, int *errnop)
70{
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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;
f7293a54 81 struct group gbuf;
f7293a54 82 int old_errno = errno;
c1812233 83
8870ee9c 84 size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
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85 char *buf = malloc(buflen);
86 if (buf == NULL) {
f6903667 87 *errnop = ENOMEM;
f7293a54 88 errno = old_errno;
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89 return NSS_STATUS_TRYAGAIN;
90 }
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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 {
d905b369 100 morebuf:
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101 if (fct.l == _nss_nonlocal_getgrgid_r)
102 status = NSS_STATUS_NOTFOUND;
103 else
104 status = DL_CALL_FCT(fct.l, (gid, &gbuf, buf, buflen, errnop));
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105 if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) {
106 free(buf);
107 buflen *= 2;
108 buf = malloc(buflen);
109 if (buf == NULL) {
110 *errnop = ENOMEM;
111 errno = old_errno;
112 return NSS_STATUS_TRYAGAIN;
113 }
114 goto morebuf;
115 }
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116 } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
117
118 if (status == NSS_STATUS_SUCCESS) {
f7293a54 119 syslog(LOG_WARNING, "nss_nonlocal: removing local group %u (%s) from non-local user %s\n", gbuf.gr_gid, gbuf.gr_name, user);
f6903667 120 status = NSS_STATUS_NOTFOUND;
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121 } else if (status != NSS_STATUS_TRYAGAIN) {
122 status = NSS_STATUS_SUCCESS;
f6903667 123 }
30fb3957 124
f7293a54 125 free(buf);
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126 return status;
127}
128
48479fc7 129enum nss_status
8aa9014e 130get_local_group(const char *name, struct group *grp, char **buffer, int *errnop)
48479fc7 131{
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132 static const char *fct_name = "getgrnam_r";
133 static service_user *startp = NULL;
134 static void *fct_start = NULL;
135 enum nss_status status;
136 service_user *nip;
137 union {
138 enum nss_status (*l)(const char *name, struct group *grp,
139 char *buffer, size_t buflen, int *errnop);
140 void *ptr;
141 } fct;
8aa9014e 142 size_t buflen;
48479fc7 143 int old_errno = errno;
c1812233 144
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145 buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
146 *buffer = malloc(buflen);
147 if (*buffer == NULL) {
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148 *errnop = ENOMEM;
149 errno = old_errno;
150 return NSS_STATUS_TRYAGAIN;
151 }
1e78305d 152
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153 if (fct_start == NULL &&
154 __nss_group_lookup(&startp, fct_name, &fct_start) != 0) {
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155 free(*buffer);
156 *buffer = NULL;
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157 return NSS_STATUS_UNAVAIL;
158 }
159 nip = startp;
160 fct.ptr = fct_start;
161 do {
d905b369 162 morebuf:
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163 if (fct.l == _nss_nonlocal_getgrnam_r)
164 status = NSS_STATUS_NOTFOUND;
165 else
8aa9014e 166 status = DL_CALL_FCT(fct.l, (name, grp, *buffer, buflen, errnop));
d905b369 167 if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) {
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168 free(*buffer);
169 buflen *= 2;
170 *buffer = malloc(buflen);
171 if (*buffer == NULL) {
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172 *errnop = ENOMEM;
173 errno = old_errno;
174 return NSS_STATUS_TRYAGAIN;
175 }
176 goto morebuf;
177 }
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178 } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
179
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180 if (status != NSS_STATUS_SUCCESS) {
181 free(*buffer);
182 *buffer = NULL;
48479fc7 183 }
30fb3957 184
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185 return status;
186}
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187
188static service_user *grent_nip = NULL;
189static void *grent_fct_start;
190static union {
191 enum nss_status (*l)(struct group *grp, char *buffer, size_t buflen,
192 int *errnop);
193 void *ptr;
194} grent_fct;
195static const char *grent_fct_name = "getgrent_r";
196
197enum nss_status
198_nss_nonlocal_setgrent(int stayopen)
199{
200 static const char *fct_name = "setgrent";
201 static void *fct_start = NULL;
202 enum nss_status status;
203 service_user *nip;
204 union {
205 enum nss_status (*l)(int stayopen);
206 void *ptr;
207 } fct;
208
209 nip = nss_group_nonlocal_database();
210 if (nip == NULL)
211 return NSS_STATUS_UNAVAIL;
212 if (fct_start == NULL)
213 fct_start = __nss_lookup_function(nip, fct_name);
214 fct.ptr = fct_start;
215 do {
216 if (fct.ptr == NULL)
217 status = NSS_STATUS_UNAVAIL;
218 else
219 status = DL_CALL_FCT(fct.l, (stayopen));
220 } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
221 if (status != NSS_STATUS_SUCCESS)
222 return status;
223
224 grent_nip = nip;
225 if (grent_fct_start == NULL)
226 grent_fct_start = __nss_lookup_function(nip, grent_fct_name);
227 grent_fct.ptr = grent_fct_start;
228 return NSS_STATUS_SUCCESS;
229}
230
231enum nss_status
232_nss_nonlocal_endgrent(void)
233{
234 static const char *fct_name = "endgrent";
235 static void *fct_start = NULL;
236 enum nss_status status;
237 service_user *nip;
238 union {
239 enum nss_status (*l)(void);
240 void *ptr;
241 } fct;
242
243 grent_nip = NULL;
244
245 nip = nss_group_nonlocal_database();
246 if (nip == NULL)
247 return NSS_STATUS_UNAVAIL;
248 if (fct_start == NULL)
249 fct_start = __nss_lookup_function(nip, fct_name);
250 fct.ptr = fct_start;
251 do {
252 if (fct.ptr == NULL)
253 status = NSS_STATUS_UNAVAIL;
254 else
255 status = DL_CALL_FCT(fct.l, ());
256 } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
257 return status;
258}
259
260enum nss_status
261_nss_nonlocal_getgrent_r(struct group *grp, char *buffer, size_t buflen,
262 int *errnop)
263{
264 enum nss_status status;
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265
266 char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV);
c1812233 267 if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0')
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268 return NSS_STATUS_UNAVAIL;
269
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270 if (grent_nip == NULL) {
271 status = _nss_nonlocal_setgrent(0);
272 if (status != NSS_STATUS_SUCCESS)
273 return status;
274 }
275 do {
276 if (grent_fct.ptr == NULL)
277 status = NSS_STATUS_UNAVAIL;
278 else {
279 int nonlocal_errno;
280 do
281 status = DL_CALL_FCT(grent_fct.l, (grp, buffer, buflen, errnop));
282 while (status == NSS_STATUS_SUCCESS &&
283 check_nonlocal_gid("(unknown)", grp->gr_gid, &nonlocal_errno) != NSS_STATUS_SUCCESS);
284 }
285 if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE)
286 return status;
287
288 if (status == NSS_STATUS_SUCCESS)
289 return NSS_STATUS_SUCCESS;
290 } while (__nss_next(&grent_nip, grent_fct_name, &grent_fct.ptr, status, 0) == 0);
291
292 grent_nip = NULL;
293 return NSS_STATUS_NOTFOUND;
294}
295
296
297enum nss_status
298_nss_nonlocal_getgrnam_r(const char *name, struct group *grp,
299 char *buffer, size_t buflen, int *errnop)
300{
301 static const char *fct_name = "getgrnam_r";
302 static void *fct_start = NULL;
303 enum nss_status status;
304 service_user *nip;
305 union {
306 enum nss_status (*l)(const char *name, struct group *grp,
307 char *buffer, size_t buflen, int *errnop);
308 void *ptr;
309 } fct;
310
a360549e 311 char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV);
c1812233 312 if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0')
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313 return NSS_STATUS_UNAVAIL;
314
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315 nip = nss_group_nonlocal_database();
316 if (nip == NULL)
317 return NSS_STATUS_UNAVAIL;
318 if (fct_start == NULL)
319 fct_start = __nss_lookup_function(nip, fct_name);
320 fct.ptr = fct_start;
321 do {
322 if (fct.ptr == NULL)
323 status = NSS_STATUS_UNAVAIL;
324 else
325 status = DL_CALL_FCT(fct.l, (name, grp, buffer, buflen, errnop));
326 if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE)
327 break;
328 } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
329 if (status != NSS_STATUS_SUCCESS)
330 return status;
331
332 return check_nonlocal_gid(name, grp->gr_gid, errnop);
333}
334
335enum nss_status
336_nss_nonlocal_getgrgid_r(gid_t gid, struct group *grp,
337 char *buffer, size_t buflen, int *errnop)
338{
339 static const char *fct_name = "getgrgid_r";
340 static void *fct_start = NULL;
341 enum nss_status status;
342 service_user *nip;
343 union {
344 enum nss_status (*l)(gid_t gid, struct group *grp,
345 char *buffer, size_t buflen, int *errnop);
346 void *ptr;
347 } fct;
348
a360549e 349 char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV);
c1812233 350 if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0')
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351 return NSS_STATUS_UNAVAIL;
352
353 nip = nss_group_nonlocal_database();
354 if (nip == NULL)
355 return NSS_STATUS_UNAVAIL;
356 if (fct_start == NULL)
357 fct_start = __nss_lookup_function(nip, fct_name);
358 fct.ptr = fct_start;
359 do {
360 if (fct.ptr == NULL)
361 status = NSS_STATUS_UNAVAIL;
362 else
363 status = DL_CALL_FCT(fct.l, (gid, grp, buffer, buflen, errnop));
364 if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE)
365 break;
366 } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
367 if (status != NSS_STATUS_SUCCESS)
368 return status;
369
370 return check_nonlocal_gid(grp->gr_name, grp->gr_gid, errnop);
371}
372
373enum nss_status
374_nss_nonlocal_initgroups_dyn(const char *user, gid_t group, long int *start,
375 long int *size, gid_t **groupsp, long int limit,
376 int *errnop)
377{
378 static const char *fct_name = "initgroups_dyn";
379 static void *fct_start = NULL;
380 enum nss_status status;
381 service_user *nip;
382 union {
383 enum nss_status (*l)(const char *user, gid_t group, long int *start,
384 long int *size, gid_t **groupsp, long int limit,
385 int *errnop);
386 void *ptr;
387 } fct;
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388
389 struct group local_users_group, nonlocal_users_group;
390 gid_t local_users_gid, gid;
48479fc7 391 int is_local = 0;
1e78305d 392 char *buffer;
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393 int old_errno;
394 int in, out, i;
48479fc7 395
1e78305d 396 /* Check that the user is a nonlocal user before adding any groups. */
48479fc7 397 status = check_nonlocal_user(user, errnop);
5879a696 398 if (status == NSS_STATUS_TRYAGAIN)
48479fc7 399 return status;
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400 else if (status != NSS_STATUS_SUCCESS)
401 is_local = 1;
48479fc7 402
d7bf1d11 403 old_errno = errno;
1e78305d 404
48479fc7 405 status = get_local_group(MAGIC_LOCAL_GROUPNAME,
8aa9014e 406 &local_users_group, &buffer, errnop);
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407 if (status == NSS_STATUS_SUCCESS) {
408 local_users_gid = local_users_group.gr_gid;
dc94c928 409 free(buffer);
8aa9014e 410 } else if (status == NSS_STATUS_TRYAGAIN) {
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411 return status;
412 } else {
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413 syslog(LOG_WARNING, "nss_nonlocal: Group %s does not exist locally!",
414 MAGIC_LOCAL_GROUPNAME);
1e78305d 415 local_users_gid = -1;
5879a696 416 }
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417
418 if (is_local) {
419 gid = local_users_gid;
420 } else {
1e78305d 421 status = get_local_group(MAGIC_NONLOCAL_GROUPNAME,
8aa9014e 422 &nonlocal_users_group, &buffer, errnop);
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423 if (status == NSS_STATUS_SUCCESS) {
424 gid = nonlocal_users_group.gr_gid;
dc94c928 425 free(buffer);
8aa9014e 426 } else if (status == NSS_STATUS_TRYAGAIN) {
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427 return status;
428 } else {
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429 syslog(LOG_WARNING, "nss_nonlocal: Group %s does not exist locally!",
430 MAGIC_NONLOCAL_GROUPNAME);
431 gid = -1;
5879a696 432 }
48479fc7 433 }
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434
435 if (gid != -1) {
436 int i;
437 for (i = 0; i < *start; ++i)
438 if ((*groupsp)[i] == gid)
439 break;
440 if (i >= *start) {
441 if (*start + 1 > *size) {
442 gid_t *newgroups;
443 long int newsize = 2 * *size;
444 if (limit > 0) {
445 if (*size >= limit)
446 return NSS_STATUS_SUCCESS;
447 if (newsize > limit)
448 newsize = limit;
449 }
ad0399bd 450 newgroups = realloc(*groupsp, newsize * sizeof((*groupsp)[0]));
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451 if (newgroups == NULL) {
452 *errnop = ENOMEM;
453 errno = old_errno;
454 return NSS_STATUS_TRYAGAIN;
455 }
456 *groupsp = newgroups;
457 *size = newsize;
458 }
459 (*groupsp)[(*start)++] = gid;
460 }
48479fc7 461 }
f6903667 462
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463 if (is_local)
464 return NSS_STATUS_SUCCESS;
465
d7bf1d11 466 in = out = *start;
1e78305d 467
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468 nip = nss_group_nonlocal_database();
469 if (nip == NULL)
470 return NSS_STATUS_UNAVAIL;
471 if (fct_start == NULL)
472 fct_start = __nss_lookup_function(nip, fct_name);
473 fct.ptr = fct_start;
474
475 do {
476 if (fct.ptr == NULL)
477 status = NSS_STATUS_UNAVAIL;
478 else
479 status = DL_CALL_FCT(fct.l, (user, group, start, size, groupsp, limit, errnop));
480 if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE)
481 break;
482 } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
483 if (status != NSS_STATUS_SUCCESS)
484 return status;
485
486 for (; in < *start; ++in) {
487 int nonlocal_errno = *errnop;
488
489 for (i = 0; i < out; ++i)
490 if ((*groupsp)[i] == (*groupsp)[in])
491 break;
492 if (i < out)
493 continue;
494
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495 /* Don't let users get into MAGIC_LOCAL_GROUPNAME from nonlocal reasons. */
496 if (local_users_gid == (*groupsp)[in]) {
497 syslog(LOG_WARNING, "nss_nonlocal: Nonlocal user %s removed from special local users group %s",
498 user, MAGIC_LOCAL_GROUPNAME);
499 continue;
500 }
501
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502 status = check_nonlocal_gid(user, (*groupsp)[in], &nonlocal_errno);
503 if (status == NSS_STATUS_SUCCESS) {
1e78305d 504 (*groupsp)[out++] = (*groupsp)[in];
5879a696 505 } else if (status == NSS_STATUS_TRYAGAIN) {
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506 *start = out;
507 *errnop = nonlocal_errno;
508 return status;
509 }
510 }
511
512 *start = out;
513 return NSS_STATUS_SUCCESS;
514}
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