source: trunk/debathena/debathena/libnss-nonlocal/nonlocal-group.c @ 24584

Revision 24584, 14.3 KB checked in by andersk, 14 years ago (diff)
Revert r24505 and r24506. nss_nonlocal is maintained in a separate Git repository (and is also used by scripts.mit.edu, not just Debathena). I will shortly upload a new upstream version that includes these changes.
Line 
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
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
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);
63
64    return nip;
65}
66
67
68enum nss_status
69check_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    size_t 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    morebuf:
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));
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        }
116    } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
117
118    if (status == NSS_STATUS_SUCCESS) {
119        syslog(LOG_WARNING, "nss_nonlocal: removing local group %u (%s) from non-local user %s\n", gbuf.gr_gid, gbuf.gr_name, user);
120        status = NSS_STATUS_NOTFOUND;
121    } else if (status != NSS_STATUS_TRYAGAIN) {
122        status = NSS_STATUS_SUCCESS;
123    }
124
125    free(buf);
126    return status;
127}
128
129enum nss_status
130check_nonlocal_group(const char *user, struct group *grp, int *errnop)
131{
132    enum nss_status status = NSS_STATUS_SUCCESS;
133    int old_errno = errno;
134    char *end;
135    unsigned long gid;
136
137    errno = 0;
138    gid = strtoul(grp->gr_name, &end, 10);
139    if (errno == 0 && *end == '\0' && (gid_t)gid == gid)
140        status = check_nonlocal_gid(user, gid, errnop);
141    errno = old_errno;
142    if (status != NSS_STATUS_SUCCESS)
143        return status;
144
145    return check_nonlocal_gid(user, grp->gr_gid, errnop);
146}
147
148enum nss_status
149get_local_group(const char *name, struct group *grp, char **buffer, int *errnop)
150{
151    static const char *fct_name = "getgrnam_r";
152    static service_user *startp = NULL;
153    static void *fct_start = NULL;
154    enum nss_status status;
155    service_user *nip;
156    union {
157        enum nss_status (*l)(const char *name, struct group *grp,
158                             char *buffer, size_t buflen, int *errnop);
159        void *ptr;
160    } fct;
161    size_t buflen;
162    int old_errno = errno;
163
164    buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
165    *buffer = malloc(buflen);
166    if (*buffer == NULL) {
167        *errnop = ENOMEM;
168        errno = old_errno;
169        return NSS_STATUS_TRYAGAIN;
170    }
171
172    if (fct_start == NULL &&
173        __nss_group_lookup(&startp, fct_name, &fct_start) != 0) {
174        free(*buffer);
175        *buffer = NULL;
176        return NSS_STATUS_UNAVAIL;
177    }
178    nip = startp;
179    fct.ptr = fct_start;
180    do {
181    morebuf:
182        if (fct.l == _nss_nonlocal_getgrnam_r)
183            status = NSS_STATUS_NOTFOUND;
184        else
185            status = DL_CALL_FCT(fct.l, (name, grp, *buffer, buflen, errnop));
186        if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) {
187            free(*buffer);
188            buflen *= 2;
189            *buffer = malloc(buflen);
190            if (*buffer == NULL) {
191                *errnop = ENOMEM;
192                errno = old_errno;
193                return NSS_STATUS_TRYAGAIN;
194            }
195            goto morebuf;
196        }
197    } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
198
199    if (status != NSS_STATUS_SUCCESS) {
200        free(*buffer);
201        *buffer = NULL;
202    }
203
204    return status;
205}
206
207static service_user *grent_nip = NULL;
208static void *grent_fct_start;
209static union {
210    enum nss_status (*l)(struct group *grp, char *buffer, size_t buflen,
211                         int *errnop);
212    void *ptr;
213} grent_fct;
214static const char *grent_fct_name = "getgrent_r";
215
216enum nss_status
217_nss_nonlocal_setgrent(int stayopen)
218{
219    static const char *fct_name = "setgrent";
220    static void *fct_start = NULL;
221    enum nss_status status;
222    service_user *nip;
223    union {
224        enum nss_status (*l)(int stayopen);
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, (stayopen));
239    } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
240    if (status != NSS_STATUS_SUCCESS)
241        return status;
242
243    grent_nip = nip;
244    if (grent_fct_start == NULL)
245        grent_fct_start = __nss_lookup_function(nip, grent_fct_name);
246    grent_fct.ptr = grent_fct_start;
247    return NSS_STATUS_SUCCESS;
248}
249
250enum nss_status
251_nss_nonlocal_endgrent(void)
252{
253    static const char *fct_name = "endgrent";
254    static void *fct_start = NULL;
255    enum nss_status status;
256    service_user *nip;
257    union {
258        enum nss_status (*l)(void);
259        void *ptr;
260    } fct;
261
262    grent_nip = NULL;
263
264    nip = nss_group_nonlocal_database();
265    if (nip == NULL)
266        return NSS_STATUS_UNAVAIL;
267    if (fct_start == NULL)
268        fct_start = __nss_lookup_function(nip, fct_name);
269    fct.ptr = fct_start;
270    do {
271        if (fct.ptr == NULL)
272            status = NSS_STATUS_UNAVAIL;
273        else
274            status = DL_CALL_FCT(fct.l, ());
275    } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
276    return status;
277}
278
279enum nss_status
280_nss_nonlocal_getgrent_r(struct group *grp, char *buffer, size_t buflen,
281                         int *errnop)
282{
283    enum nss_status status;
284
285    char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV);
286    if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0')
287        return NSS_STATUS_UNAVAIL;
288
289    if (grent_nip == NULL) {
290        status = _nss_nonlocal_setgrent(0);
291        if (status != NSS_STATUS_SUCCESS)
292            return status;
293    }
294    do {
295        if (grent_fct.ptr == NULL)
296            status = NSS_STATUS_UNAVAIL;
297        else {
298            int nonlocal_errno;
299            do
300                status = DL_CALL_FCT(grent_fct.l, (grp, buffer, buflen, errnop));
301            while (status == NSS_STATUS_SUCCESS &&
302                   check_nonlocal_group("(unknown)", grp, &nonlocal_errno) != NSS_STATUS_SUCCESS);
303        }
304        if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE)
305            return status;
306
307        if (status == NSS_STATUS_SUCCESS)
308            return NSS_STATUS_SUCCESS;
309    } while (__nss_next(&grent_nip, grent_fct_name, &grent_fct.ptr, status, 0) == 0);
310
311    grent_nip = NULL;
312    return NSS_STATUS_NOTFOUND;
313}
314
315
316enum nss_status
317_nss_nonlocal_getgrnam_r(const char *name, struct group *grp,
318                         char *buffer, size_t buflen, int *errnop)
319{
320    static const char *fct_name = "getgrnam_r";
321    static void *fct_start = NULL;
322    enum nss_status status;
323    service_user *nip;
324    union {
325        enum nss_status (*l)(const char *name, struct group *grp,
326                             char *buffer, size_t buflen, int *errnop);
327        void *ptr;
328    } fct;
329
330    char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV);
331    if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0')
332        return NSS_STATUS_UNAVAIL;
333
334    nip = nss_group_nonlocal_database();
335    if (nip == NULL)
336        return NSS_STATUS_UNAVAIL;
337    if (fct_start == NULL)
338        fct_start = __nss_lookup_function(nip, fct_name);
339    fct.ptr = fct_start;
340    do {
341        if (fct.ptr == NULL)
342            status = NSS_STATUS_UNAVAIL;
343        else
344            status = DL_CALL_FCT(fct.l, (name, grp, buffer, buflen, errnop));
345        if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE)
346            break;
347    } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
348    if (status != NSS_STATUS_SUCCESS)
349        return status;
350
351    if (strcmp(name, grp->gr_name) != 0) {
352        syslog(LOG_ERR, "nss_nonlocal: discarding group %s from lookup for group %s\n", grp->gr_name, name);
353        return NSS_STATUS_NOTFOUND;
354    }
355
356    return check_nonlocal_group(name, grp, errnop);
357}
358
359enum nss_status
360_nss_nonlocal_getgrgid_r(gid_t gid, struct group *grp,
361                         char *buffer, size_t buflen, int *errnop)
362{
363    static const char *fct_name = "getgrgid_r";
364    static void *fct_start = NULL;
365    enum nss_status status;
366    service_user *nip;
367    union {
368        enum nss_status (*l)(gid_t gid, struct group *grp,
369                             char *buffer, size_t buflen, int *errnop);
370        void *ptr;
371    } fct;
372
373    char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV);
374    if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0')
375        return NSS_STATUS_UNAVAIL;
376
377    nip = nss_group_nonlocal_database();
378    if (nip == NULL)
379        return NSS_STATUS_UNAVAIL;
380    if (fct_start == NULL)
381        fct_start = __nss_lookup_function(nip, fct_name);
382    fct.ptr = fct_start;
383    do {
384        if (fct.ptr == NULL)
385            status = NSS_STATUS_UNAVAIL;
386        else
387            status = DL_CALL_FCT(fct.l, (gid, grp, buffer, buflen, errnop));
388        if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE)
389            break;
390    } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
391    if (status != NSS_STATUS_SUCCESS)
392        return status;
393
394    return check_nonlocal_group(grp->gr_name, grp, errnop);
395}
396
397enum nss_status
398_nss_nonlocal_initgroups_dyn(const char *user, gid_t group, long int *start,
399                             long int *size, gid_t **groupsp, long int limit,
400                             int *errnop)
401{
402    static const char *fct_name = "initgroups_dyn";
403    static void *fct_start = NULL;
404    enum nss_status status;
405    service_user *nip;
406    union {
407        enum nss_status (*l)(const char *user, gid_t group, long int *start,
408                             long int *size, gid_t **groupsp, long int limit,
409                             int *errnop);
410        void *ptr;
411    } fct;
412
413    struct group local_users_group, nonlocal_users_group;
414    gid_t local_users_gid, gid;
415    int is_local = 0;
416    char *buffer;
417    int old_errno;
418    int in, out, i;
419
420    /* Check that the user is a nonlocal user before adding any groups. */
421    status = check_nonlocal_user(user, errnop);
422    if (status == NSS_STATUS_TRYAGAIN)
423        return status;
424    else if (status != NSS_STATUS_SUCCESS)
425        is_local = 1;
426
427    old_errno = errno;
428
429    status = get_local_group(MAGIC_LOCAL_GROUPNAME,
430                             &local_users_group, &buffer, errnop);
431    if (status == NSS_STATUS_SUCCESS) {
432        local_users_gid = local_users_group.gr_gid;
433        free(buffer);
434    } else if (status == NSS_STATUS_TRYAGAIN) {
435        return status;
436    } else {
437        syslog(LOG_WARNING, "nss_nonlocal: Group %s does not exist locally!",
438               MAGIC_LOCAL_GROUPNAME);
439        local_users_gid = -1;
440    }
441
442    if (is_local) {
443        gid = local_users_gid;
444    } else {
445        status = get_local_group(MAGIC_NONLOCAL_GROUPNAME,
446                                 &nonlocal_users_group, &buffer, errnop);
447        if (status == NSS_STATUS_SUCCESS) {
448            gid = nonlocal_users_group.gr_gid;
449            free(buffer);
450        } else if (status == NSS_STATUS_TRYAGAIN) {
451            return status;
452        } else {
453            syslog(LOG_WARNING, "nss_nonlocal: Group %s does not exist locally!",
454                   MAGIC_NONLOCAL_GROUPNAME);
455            gid = -1;
456        }
457    }
458
459    if (gid != -1) {
460        int i;
461        for (i = 0; i < *start; ++i)
462            if ((*groupsp)[i] == gid)
463                break;
464        if (i >= *start) {
465            if (*start + 1 > *size) {
466                gid_t *newgroups;
467                long int newsize = 2 * *size;
468                if (limit > 0) {
469                    if (*size >= limit)
470                        return NSS_STATUS_SUCCESS;
471                    if (newsize > limit)
472                        newsize = limit;
473                }
474                newgroups = realloc(*groupsp, newsize * sizeof((*groupsp)[0]));
475                if (newgroups == NULL) {
476                    *errnop = ENOMEM;
477                    errno = old_errno;
478                    return NSS_STATUS_TRYAGAIN;
479                }
480                *groupsp = newgroups;
481                *size = newsize;
482            }
483            (*groupsp)[(*start)++] = gid;
484        }
485    }
486
487    if (is_local)
488        return NSS_STATUS_SUCCESS;
489
490    in = out = *start;
491
492    nip = nss_group_nonlocal_database();
493    if (nip == NULL)
494        return NSS_STATUS_UNAVAIL;
495    if (fct_start == NULL)
496        fct_start = __nss_lookup_function(nip, fct_name);
497    fct.ptr = fct_start;
498
499    do {
500        if (fct.ptr == NULL)
501            status = NSS_STATUS_UNAVAIL;
502        else
503            status = DL_CALL_FCT(fct.l, (user, group, start, size, groupsp, limit, errnop));
504        if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE)
505            break;
506    } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
507    if (status != NSS_STATUS_SUCCESS)
508        return status;
509
510    for (; in < *start; ++in) {
511        int nonlocal_errno = *errnop;
512
513        for (i = 0; i < out; ++i)
514            if ((*groupsp)[i] == (*groupsp)[in])
515                break;
516        if (i < out)
517            continue;
518
519        /* Don't let users get into MAGIC_LOCAL_GROUPNAME from nonlocal reasons. */
520        if (local_users_gid == (*groupsp)[in]) {
521            syslog(LOG_WARNING, "nss_nonlocal: Nonlocal user %s removed from special local users group %s",
522                   user, MAGIC_LOCAL_GROUPNAME);
523            continue;
524        }
525
526        status = check_nonlocal_gid(user, (*groupsp)[in], &nonlocal_errno);
527        if (status == NSS_STATUS_SUCCESS) {
528            (*groupsp)[out++] = (*groupsp)[in];
529        } else if (status == NSS_STATUS_TRYAGAIN) {
530            *start = out;
531            *errnop = nonlocal_errno;
532            return status;
533        }
534    }
535
536    *start = out;
537    return NSS_STATUS_SUCCESS;
538}
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