source: trunk/debathena/debathena/libnss-nonlocal/nonlocal-group.c @ 22768

Revision 22768, 13.2 KB checked in by tabbott, 17 years ago (diff)
Make it possible to add new users/groups with the same name as Athena users and groups. * debathena/libnss-nonlocal/: If NSS_NONLOCAL_IGNORE is set, pretend that nonlocal information doesn't exist. * config/nsswitch-config/debian/: Divert and wrap adduser, useradd, groupadd, addgroup, dpkg to set NSS_NONLOCAL_IGNORE when adding new accounts both manually and when installing new packages.
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_LOCAL_GR_BUFLEN (sysconf(_SC_GETGR_R_SIZE_MAX) + 7)
45#define MAGIC_NONLOCAL_GROUPNAME "nss-nonlocal-users"
46#define MAGIC_LOCAL_GROUPNAME "nss-local-users"
47
48
49static service_user *
50nss_group_nonlocal_database(void)
51{
52    static service_user *nip = NULL;
53    if (nip == NULL)
54        __nss_database_lookup("group_nonlocal", NULL, "", &nip);
55
56    return nip;
57}
58
59
60enum nss_status
61check_nonlocal_gid(const char *user, gid_t gid, int *errnop)
62{
63    enum nss_status status = NSS_STATUS_SUCCESS;
64    struct group gbuf;
65    struct group *gbufp = &gbuf;
66    int ret;
67    int old_errno = errno;
68    int buflen = MAGIC_LOCAL_GR_BUFLEN;
69    char *buf = malloc(buflen);
70    if (buf == NULL) {
71        *errnop = ENOMEM;
72        errno = old_errno;
73        return NSS_STATUS_TRYAGAIN;
74    }
75    errno = 0;
76    ret = getgrgid_r(gid, gbufp, buf, buflen, &gbufp);
77    if (ret != 0) {
78        *errnop = old_errno;
79        status = NSS_STATUS_TRYAGAIN;
80    } else if (gbufp != NULL) {
81        syslog(LOG_WARNING, "nss_nonlocal: removing local group %u (%s) from non-local user %s\n", gbuf.gr_gid, gbuf.gr_name, user);
82        status = NSS_STATUS_NOTFOUND;
83    }
84    free(buf);
85    errno = old_errno;
86    return status;
87}
88
89enum nss_status
90get_local_group(const char *name, struct group *grp, char *buffer, size_t buflen, int *errnop)
91{
92    enum nss_status status = NSS_STATUS_NOTFOUND;
93    struct group gbuf;
94    struct group *gbufp = &gbuf;
95    int ret, n;
96    int old_errno = errno;
97    int len = MAGIC_LOCAL_GR_BUFLEN;
98    char *buf = malloc(len);
99    if (buf == NULL) {
100        *errnop = ENOMEM;
101        errno = old_errno;
102        return NSS_STATUS_TRYAGAIN;
103    }
104    errno = 0;
105    ret = getgrnam_r(name, gbufp, buf, len, &gbufp);
106    if (ret != 0) {
107        *errnop = old_errno;
108        status = NSS_STATUS_TRYAGAIN;
109    } else if (gbufp != NULL) {
110        status = NSS_STATUS_SUCCESS;
111
112        n = snprintf(buffer, buflen, "%s", gbufp->gr_name);
113        if (n < 0 || n >= buflen) {
114            *errnop = ERANGE;
115            status = NSS_STATUS_TRYAGAIN;
116            goto get_local_group_done;
117        }
118        grp->gr_name = buffer;
119        buffer += n;
120        buflen -= n;
121
122        n = snprintf(buffer, buflen, "%s", gbufp->gr_passwd);
123        if (n < 0 || n >= buflen) {
124            *errnop = ERANGE;
125            status = NSS_STATUS_TRYAGAIN;
126            goto get_local_group_done;
127        }
128        grp->gr_passwd = buffer;
129        buffer += n;
130        buflen -= n;
131
132        grp->gr_gid = gbufp->gr_gid;
133
134        if (buflen < sizeof(void *)) {
135            *errnop = ERANGE;
136            status = NSS_STATUS_TRYAGAIN;
137            goto get_local_group_done;
138        }
139        *(void **)buffer = NULL;
140        buffer += sizeof(void *);
141        buflen -= sizeof(void *);
142    }
143 get_local_group_done:
144    free(buf);
145    errno = old_errno;
146    return status;
147}
148
149static service_user *grent_nip = NULL;
150static void *grent_fct_start;
151static union {
152    enum nss_status (*l)(struct group *grp, char *buffer, size_t buflen,
153                         int *errnop);
154    void *ptr;
155} grent_fct;
156static const char *grent_fct_name = "getgrent_r";
157
158enum nss_status
159_nss_nonlocal_setgrent(int stayopen)
160{
161    static const char *fct_name = "setgrent";
162    static void *fct_start = NULL;
163    enum nss_status status;
164    service_user *nip;
165    union {
166        enum nss_status (*l)(int stayopen);
167        void *ptr;
168    } fct;
169
170    nip = nss_group_nonlocal_database();
171    if (nip == NULL)
172        return NSS_STATUS_UNAVAIL;
173    if (fct_start == NULL)
174        fct_start = __nss_lookup_function(nip, fct_name);
175    fct.ptr = fct_start;
176    do {
177        if (fct.ptr == NULL)
178            status = NSS_STATUS_UNAVAIL;
179        else
180            status = DL_CALL_FCT(fct.l, (stayopen));
181    } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
182    if (status != NSS_STATUS_SUCCESS)
183        return status;
184
185    grent_nip = nip;
186    if (grent_fct_start == NULL)
187        grent_fct_start = __nss_lookup_function(nip, grent_fct_name);
188    grent_fct.ptr = grent_fct_start;
189    return NSS_STATUS_SUCCESS;
190}
191
192enum nss_status
193_nss_nonlocal_endgrent(void)
194{
195    static const char *fct_name = "endgrent";
196    static void *fct_start = NULL;
197    enum nss_status status;
198    service_user *nip;
199    union {
200        enum nss_status (*l)(void);
201        void *ptr;
202    } fct;
203
204    grent_nip = NULL;
205
206    nip = nss_group_nonlocal_database();
207    if (nip == NULL)
208        return NSS_STATUS_UNAVAIL;
209    if (fct_start == NULL)
210        fct_start = __nss_lookup_function(nip, fct_name);
211    fct.ptr = fct_start;
212    do {
213        if (fct.ptr == NULL)
214            status = NSS_STATUS_UNAVAIL;
215        else
216            status = DL_CALL_FCT(fct.l, ());
217    } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
218    return status;
219}
220
221enum nss_status
222_nss_nonlocal_getgrent_r(struct group *grp, char *buffer, size_t buflen,
223                         int *errnop)
224{
225    enum nss_status status;
226
227    char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV);
228    if (buflen == MAGIC_LOCAL_GR_BUFLEN ||
229        (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0'))
230        return NSS_STATUS_UNAVAIL;
231
232    if (grent_nip == NULL) {
233        status = _nss_nonlocal_setgrent(0);
234        if (status != NSS_STATUS_SUCCESS)
235            return status;
236    }
237    do {
238        if (grent_fct.ptr == NULL)
239            status = NSS_STATUS_UNAVAIL;
240        else {
241            int nonlocal_errno;
242            do
243                status = DL_CALL_FCT(grent_fct.l, (grp, buffer, buflen, errnop));
244            while (status == NSS_STATUS_SUCCESS &&
245                   check_nonlocal_gid("(unknown)", grp->gr_gid, &nonlocal_errno) != NSS_STATUS_SUCCESS);
246        }
247        if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE)
248            return status;
249
250        if (status == NSS_STATUS_SUCCESS)
251            return NSS_STATUS_SUCCESS;
252    } while (__nss_next(&grent_nip, grent_fct_name, &grent_fct.ptr, status, 0) == 0);
253
254    grent_nip = NULL;
255    return NSS_STATUS_NOTFOUND;
256}
257
258
259enum nss_status
260_nss_nonlocal_getgrnam_r(const char *name, struct group *grp,
261                         char *buffer, size_t buflen, int *errnop)
262{
263    static const char *fct_name = "getgrnam_r";
264    static void *fct_start = NULL;
265    enum nss_status status;
266    service_user *nip;
267    union {
268        enum nss_status (*l)(const char *name, struct group *grp,
269                             char *buffer, size_t buflen, int *errnop);
270        void *ptr;
271    } fct;
272
273    char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV);
274    if (buflen == MAGIC_LOCAL_GR_BUFLEN ||
275        (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0'))
276        return NSS_STATUS_UNAVAIL;
277
278    nip = nss_group_nonlocal_database();
279    if (nip == NULL)
280        return NSS_STATUS_UNAVAIL;
281    if (fct_start == NULL)
282        fct_start = __nss_lookup_function(nip, fct_name);
283    fct.ptr = fct_start;
284    do {
285        if (fct.ptr == NULL)
286            status = NSS_STATUS_UNAVAIL;
287        else
288            status = DL_CALL_FCT(fct.l, (name, grp, buffer, buflen, errnop));
289        if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE)
290            break;
291    } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
292    if (status != NSS_STATUS_SUCCESS)
293        return status;
294
295    return check_nonlocal_gid(name, grp->gr_gid, errnop);
296}
297
298enum nss_status
299_nss_nonlocal_getgrgid_r(gid_t gid, struct group *grp,
300                         char *buffer, size_t buflen, int *errnop)
301{
302    static const char *fct_name = "getgrgid_r";
303    static void *fct_start = NULL;
304    enum nss_status status;
305    service_user *nip;
306    union {
307        enum nss_status (*l)(gid_t gid, struct group *grp,
308                             char *buffer, size_t buflen, int *errnop);
309        void *ptr;
310    } fct;
311
312    char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV);
313    if (buflen == MAGIC_LOCAL_GR_BUFLEN ||
314        (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0'))
315        return NSS_STATUS_UNAVAIL;
316
317    nip = nss_group_nonlocal_database();
318    if (nip == NULL)
319        return NSS_STATUS_UNAVAIL;
320    if (fct_start == NULL)
321        fct_start = __nss_lookup_function(nip, fct_name);
322    fct.ptr = fct_start;
323    do {
324        if (fct.ptr == NULL)
325            status = NSS_STATUS_UNAVAIL;
326        else
327            status = DL_CALL_FCT(fct.l, (gid, grp, buffer, buflen, errnop));
328        if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE)
329            break;
330    } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
331    if (status != NSS_STATUS_SUCCESS)
332        return status;
333
334    return check_nonlocal_gid(grp->gr_name, grp->gr_gid, errnop);
335}
336
337enum nss_status
338_nss_nonlocal_initgroups_dyn(const char *user, gid_t group, long int *start,
339                             long int *size, gid_t **groupsp, long int limit,
340                             int *errnop)
341{
342    static const char *fct_name = "initgroups_dyn";
343    static void *fct_start = NULL;
344    enum nss_status status;
345    service_user *nip;
346    union {
347        enum nss_status (*l)(const char *user, gid_t group, long int *start,
348                             long int *size, gid_t **groupsp, long int limit,
349                             int *errnop);
350        void *ptr;
351    } fct;
352
353    struct group local_users_group, nonlocal_users_group;
354    gid_t local_users_gid, gid;
355    int is_local = 0;
356    int buflen;
357    char *buffer;
358
359    /* Check that the user is a nonlocal user before adding any groups. */
360    status = check_nonlocal_user(user, errnop);
361    if (status == NSS_STATUS_NOTFOUND)
362        is_local = 1;
363    else if (status != NSS_STATUS_SUCCESS)
364        return status;
365
366    int old_errno = errno;
367
368    buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
369    buffer = malloc(buflen);
370    if (buffer == NULL) {
371        *errnop = ENOMEM;
372        errno = old_errno;
373        return NSS_STATUS_TRYAGAIN;
374    }
375    status = get_local_group(MAGIC_LOCAL_GROUPNAME,
376                             &local_users_group, buffer, buflen, errnop);
377    if (status == NSS_STATUS_NOTFOUND) {
378        syslog(LOG_WARNING, "nss_nonlocal: Group %s does not exist locally!",
379               MAGIC_LOCAL_GROUPNAME);
380        local_users_gid = -1;
381    } else if (status != NSS_STATUS_SUCCESS) {
382        return status;
383    } else
384        local_users_gid = local_users_group.gr_gid;
385    free(buffer);
386
387    if (is_local) {
388        gid = local_users_gid;
389    } else {
390        buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
391        buffer = malloc(buflen);
392        if (buffer == NULL) {
393            *errnop = ENOMEM;
394            errno = old_errno;
395            return NSS_STATUS_TRYAGAIN;
396        }
397        status = get_local_group(MAGIC_NONLOCAL_GROUPNAME,
398                                 &nonlocal_users_group, buffer, buflen, errnop);
399        if (status == NSS_STATUS_NOTFOUND) {
400            syslog(LOG_WARNING, "nss_nonlocal: Group %s does not exist locally!",
401                   MAGIC_NONLOCAL_GROUPNAME);
402            gid = -1;
403        } else if (status != NSS_STATUS_SUCCESS) {
404            errno = old_errno;
405            return status;
406        } else
407            gid = nonlocal_users_group.gr_gid;
408        free(buffer);
409    }
410
411    if (gid != -1) {
412        int i;
413        for (i = 0; i < *start; ++i)
414            if ((*groupsp)[i] == gid)
415                break;
416        if (i >= *start) {
417            if (*start + 1 > *size) {
418                gid_t *newgroups;
419                long int newsize = 2 * *size;
420                if (limit > 0) {
421                    if (*size >= limit)
422                        return NSS_STATUS_SUCCESS;
423                    if (newsize > limit)
424                        newsize = limit;
425                }
426                newgroups = realloc(*groupsp, *size * sizeof((*groupsp)[0]));
427                if (newgroups == NULL) {
428                    *errnop = ENOMEM;
429                    errno = old_errno;
430                    return NSS_STATUS_TRYAGAIN;
431                }
432                *groupsp = newgroups;
433                *size = newsize;
434            }
435            (*groupsp)[(*start)++] = gid;
436        }
437    }
438
439    errno = old_errno;
440
441    if (is_local)
442        return NSS_STATUS_SUCCESS;
443
444    int in = *start, out = *start, i;
445
446    nip = nss_group_nonlocal_database();
447    if (nip == NULL)
448        return NSS_STATUS_UNAVAIL;
449    if (fct_start == NULL)
450        fct_start = __nss_lookup_function(nip, fct_name);
451    fct.ptr = fct_start;
452
453    do {
454        if (fct.ptr == NULL)
455            status = NSS_STATUS_UNAVAIL;
456        else
457            status = DL_CALL_FCT(fct.l, (user, group, start, size, groupsp, limit, errnop));
458        if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE)
459            break;
460    } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0);
461    if (status != NSS_STATUS_SUCCESS)
462        return status;
463
464    for (; in < *start; ++in) {
465        int nonlocal_errno = *errnop;
466
467        for (i = 0; i < out; ++i)
468            if ((*groupsp)[i] == (*groupsp)[in])
469                break;
470        if (i < out)
471            continue;
472
473        /* Don't let users get into MAGIC_LOCAL_GROUPNAME from nonlocal reasons. */
474        if (local_users_gid == (*groupsp)[in]) {
475            syslog(LOG_WARNING, "nss_nonlocal: Nonlocal user %s removed from special local users group %s",
476                   user, MAGIC_LOCAL_GROUPNAME);
477            continue;
478        }
479
480        status = check_nonlocal_gid(user, (*groupsp)[in], &nonlocal_errno);
481        if (status == NSS_STATUS_SUCCESS) {
482            (*groupsp)[out++] = (*groupsp)[in];
483        } else if (status != NSS_STATUS_NOTFOUND) {
484            *start = out;
485            *errnop = nonlocal_errno;
486            return status;
487        }
488    }
489
490    *start = out;
491    return NSS_STATUS_SUCCESS;
492}
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