about summary refs log tree commit diff
path: root/nis/nss_nis/nis-initgroups.c
blob: ec9f9e1970ec114335741c60bd3d9079342b56ed (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
/* Copyright (C) 1998-2019 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Thorsten Kukuk <kukuk@suse.de>, 1998.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <ctype.h>
#include <errno.h>
#include <grp.h>
#include <nss.h>
#include <pwd.h>
#include <string.h>
#include <unistd.h>
#include <rpcsvc/yp.h>
#include <rpcsvc/ypclnt.h>
#include <sys/param.h>
#include <scratch_buffer.h>

#include "nss-nis.h"
#include <libnsl.h>

/* Get the declaration of the parser function.  */
#define ENTNAME grent
#define STRUCTURE group
#define EXTERN_PARSER
#include <nss/nss_files/files-parse.c>


static enum nss_status
internal_setgrent (char *domainname, intern_t *intern)
{
  struct ypall_callback ypcb;
  enum nss_status status;

  ypcb.foreach = _nis_saveit;
  ypcb.data = (char *) intern;
  status = yperr2nss (yp_all (domainname, "group.byname", &ypcb));

  /* Mark the last buffer as full.  */
  if (intern->next != NULL)
    intern->next->size = intern->offset;

  intern->next = intern->start;
  intern->offset = 0;

  return status;
}


static enum nss_status
internal_getgrent_r (struct group *grp, char *buffer, size_t buflen,
		     int *errnop, intern_t *intern)
{
  if (intern->start == NULL)
    return NSS_STATUS_NOTFOUND;

  /* Get the next entry until we found a correct one. */
  int parse_res;
  do
    {
      struct response_t *bucket = intern->next;

      if (__glibc_unlikely (intern->offset >= bucket->size))
	{
	  if (bucket->next == NULL)
	    return NSS_STATUS_NOTFOUND;

	  /* We look at all the content in the current bucket.  Go on
	     to the next.  */
	  bucket = intern->next = bucket->next;
	  intern->offset = 0;
	}

      char *p;
      for (p = &bucket->mem[intern->offset]; isspace (*p); ++p)
        ++intern->offset;

      size_t len = strlen (p) + 1;
      if (__glibc_unlikely (len > buflen))
	{
	  *errnop = ERANGE;
	  return NSS_STATUS_TRYAGAIN;
	}

      /* We unfortunately have to copy the data in the user-provided
	 buffer because that buffer might be around for a very long
	 time and the servent structure must remain valid.  If we would
	 rely on the BUCKET memory the next 'setservent' or 'endservent'
	 call would destroy it.

	 The important thing is that it is a single NUL-terminated
	 string.  This is what the parsing routine expects.  */
      p = memcpy (buffer, &bucket->mem[intern->offset], len);

      parse_res = _nss_files_parse_grent (p, grp, (void *) buffer, buflen,
					  errnop);
      if (__glibc_unlikely (parse_res == -1))
        return NSS_STATUS_TRYAGAIN;

      intern->offset += len;
    }
  while (!parse_res);

  return NSS_STATUS_SUCCESS;
}


static int
get_uid (const char *user, uid_t *uidp)
{
  struct scratch_buffer tmpbuf;
  scratch_buffer_init (&tmpbuf);

  while (1)
    {
      struct passwd result;
      struct passwd *resp;

      int r = getpwnam_r (user, &result, tmpbuf.data, tmpbuf.length, &resp);
      if (r == 0 && resp != NULL)
	{
	  *uidp = resp->pw_uid;
	  scratch_buffer_free (&tmpbuf);
	  return 0;
	}

      if (r != ERANGE)
	break;

      if (!scratch_buffer_grow (&tmpbuf))
	return 1;
    }

  scratch_buffer_free (&tmpbuf);
  return 1;
}


static enum nss_status
initgroups_netid (uid_t uid, gid_t group, long int *start, long int *size,
		  gid_t **groupsp, long int limit, int *errnop,
		  const char *domainname)
{
  /* Limit domainname length to the maximum size of an RPC packet.  */
  if (strlen (domainname) > UDPMSGSIZE)
    {
      *errnop = ERANGE;
      return NSS_STATUS_UNAVAIL;
    }

  /* Prepare the key.  The form is "unix.UID@DOMAIN" with the UID and
     DOMAIN field filled in appropriately.  */
  char key[sizeof ("unix.@") + sizeof (uid_t) * 3 + strlen (domainname)];
  ssize_t keylen = snprintf (key, sizeof (key), "unix.%lu@%s",
			     (unsigned long int) uid, domainname);

  char *result;
  int reslen;
  int yperr = yp_match (domainname, "netid.byname", key, keylen, &result,
			&reslen);
  if (__glibc_unlikely (yperr != YPERR_SUCCESS))
    return yperr2nss (yperr);

  /* Parse the result: following the colon is a comma separated list of
     group IDs.  */
  char *cp = strchr (result, ':');
  if (cp == NULL)
    {
    errout:
      free (result);
      return NSS_STATUS_NOTFOUND;
    }
  /* Skip the colon.  */
  ++cp;

  gid_t *groups = *groupsp;
  while (*cp != '\0')
    {
      char *endp;
      unsigned long int gid = strtoul (cp, &endp, 0);
      if (cp == endp)
	goto errout;
      if (*endp == ',')
	++endp;
      else if (*endp != '\0')
	goto errout;
      cp = endp;

      if (gid == group)
	/* We do not need this group again.  */
	continue;

      /* Insert this group.  */
      if (*start == *size)
	{
	  /* Need a bigger buffer.  */
	  long int newsize;

	  if (limit > 0 && *size == limit)
	    /* We reached the maximum.  */
	    break;

	  if (limit <= 0)
	    newsize = 2 * *size;
	  else
	    newsize = MIN (limit, 2 * *size);

	  gid_t *newgroups = realloc (groups, newsize * sizeof (*groups));
	  if (newgroups == NULL)
	    goto errout;
	  *groupsp = groups = newgroups;
	  *size = newsize;
	}

      groups[*start] = gid;
      *start += 1;
    }

  free (result);

  return NSS_STATUS_SUCCESS;
}


enum nss_status
_nss_nis_initgroups_dyn (const char *user, gid_t group, long int *start,
			 long int *size, gid_t **groupsp, long int limit,
			 int *errnop)
{
  /* We always need the domain name.  */
  char *domainname;
  if (yp_get_default_domain (&domainname))
    return NSS_STATUS_UNAVAIL;

  /* Check whether we are supposed to use the netid.byname map.  */
  if (_nsl_default_nss () & NSS_FLAG_NETID_AUTHORITATIVE)
    {
      /* We need the user ID.  */
      uid_t uid;

      if (get_uid (user, &uid) == 0
	  && initgroups_netid (uid, group, start, size, groupsp, limit,
			       errnop, domainname) == NSS_STATUS_SUCCESS)
	return NSS_STATUS_SUCCESS;
    }

  struct group grpbuf, *g;
  enum nss_status status;
  intern_t intern = { NULL, NULL, 0 };
  gid_t *groups = *groupsp;

  status = internal_setgrent (domainname, &intern);
  if (status != NSS_STATUS_SUCCESS)
    return status;

  struct scratch_buffer tmpbuf;
  scratch_buffer_init (&tmpbuf);

  while (1)
    {
      while ((status =
	      internal_getgrent_r (&grpbuf, tmpbuf.data, tmpbuf.length, errnop,
				   &intern)) == NSS_STATUS_TRYAGAIN
             && *errnop == ERANGE)
	if (!scratch_buffer_grow (&tmpbuf))
	  {
	    status = NSS_STATUS_TRYAGAIN;
	    goto done;
	  }

      if (status != NSS_STATUS_SUCCESS)
	{
	  if (status == NSS_STATUS_NOTFOUND)
	    status = NSS_STATUS_SUCCESS;
	  goto done;
	}

      g = &grpbuf;
      if (g->gr_gid != group)
        {
          char **m;

          for (m = g->gr_mem; *m != NULL; ++m)
            if (strcmp (*m, user) == 0)
              {
                /* Matches user.  Insert this group.  */
                if (*start == *size)
                  {
                    /* Need a bigger buffer.  */
		    gid_t *newgroups;
		    long int newsize;

		    if (limit > 0 && *size == limit)
		      /* We reached the maximum.  */
		      goto done;

		    if (limit <= 0)
		      newsize = 2 * *size;
		    else
		      newsize = MIN (limit, 2 * *size);

		    newgroups = realloc (groups, newsize * sizeof (*groups));
		    if (newgroups == NULL)
		      {
			status = NSS_STATUS_TRYAGAIN;
			*errnop = errno;
			goto done;
		      }
		    *groupsp = groups = newgroups;
                    *size = newsize;
                  }

                groups[*start] = g->gr_gid;
		*start += 1;

                break;
              }
        }
    }

done:
  while (intern.start != NULL)
    {
      intern.next = intern.start;
      intern.start = intern.start->next;
      free (intern.next);
    }
  scratch_buffer_free (&tmpbuf);

  return status;
}