about summary refs log tree commit diff
path: root/nscd/grpcache.c
blob: 2ad6251762b596607eedbf9cbae8e85194ab13ea (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
/* Cache handling for group lookup.
   Copyright (C) 1998-2002, 2003, 2004 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 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, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <alloca.h>
#include <errno.h>
#include <error.h>
#include <grp.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <libintl.h>
#include <stackinfo.h>

#include "nscd.h"
#include "dbg_log.h"

/* This is the standard reply in case the service is disabled.  */
static const gr_response_header disabled =
{
  .version = NSCD_VERSION,
  .found = -1,
  .gr_name_len = 0,
  .gr_passwd_len = 0,
  .gr_gid = -1,
  .gr_mem_cnt = 0,
};

/* This is the struct describing how to write this record.  */
const struct iovec grp_iov_disabled =
{
  .iov_base = (void *) &disabled,
  .iov_len = sizeof (disabled)
};


/* This is the standard reply in case we haven't found the dataset.  */
static const gr_response_header notfound =
{
  .version = NSCD_VERSION,
  .found = 0,
  .gr_name_len = 0,
  .gr_passwd_len = 0,
  .gr_gid = -1,
  .gr_mem_cnt = 0,
};


struct groupdata
{
  gr_response_header resp;
  char strdata[0];
};


static void
cache_addgr (struct database *db, int fd, request_header *req, void *key,
	     struct group *grp, uid_t owner, int type)
{
  ssize_t total;
  ssize_t written;
  time_t t = time (NULL);

  if (grp == NULL)
    {
      /* We have no data.  This means we send the standard reply for this
	 case.  */
      total = sizeof (notfound);

      written = TEMP_FAILURE_RETRY (write (fd, &notfound, total));

      void *copy = malloc (req->key_len);
      /* If we cannot allocate memory simply do not cache the information.  */
      if (copy != NULL)
	{
	  memcpy (copy, key, req->key_len);

	  /* Compute the timeout time.  */
	  t += db->negtimeout;

	  /* Now get the lock to safely insert the records.  */
	  pthread_rwlock_rdlock (&db->lock);

	  cache_add (req->type, copy, req->key_len, &notfound,
		     sizeof (notfound), (void *) -1, 0, t, db, owner);

	  pthread_rwlock_unlock (&db->lock);
	}
    }
  else
    {
      /* Determine the I/O structure.  */
      struct groupdata *data;
      size_t gr_name_len = strlen (grp->gr_name) + 1;
      size_t gr_passwd_len = strlen (grp->gr_passwd) + 1;
      size_t gr_mem_cnt = 0;
      uint32_t *gr_mem_len;
      size_t gr_mem_len_total = 0;
      char *gr_name;
      char *cp;
      char buf[12];
      ssize_t n;
      size_t cnt;

      /* We need this to insert the `bygid' entry.  */
      n = snprintf (buf, sizeof (buf), "%d", grp->gr_gid) + 1;

      /* Determine the length of all members.  */
      while (grp->gr_mem[gr_mem_cnt])
	++gr_mem_cnt;
      gr_mem_len = (uint32_t *) alloca (gr_mem_cnt * sizeof (uint32_t));
      for (gr_mem_cnt = 0; grp->gr_mem[gr_mem_cnt]; ++gr_mem_cnt)
	{
	  gr_mem_len[gr_mem_cnt] = strlen (grp->gr_mem[gr_mem_cnt]) + 1;
	  gr_mem_len_total += gr_mem_len[gr_mem_cnt];
	}

      /* We allocate all data in one memory block: the iov vector,
	 the response header and the dataset itself.  */
      total = (sizeof (struct groupdata)
	       + gr_mem_cnt * sizeof (uint32_t)
	       + gr_name_len + gr_passwd_len + gr_mem_len_total);
      data = (struct groupdata *) malloc (total + n);
      if (data == NULL)
	/* There is no reason to go on.  */
	error (EXIT_FAILURE, errno, _("while allocating cache entry"));

      data->resp.version = NSCD_VERSION;
      data->resp.found = 1;
      data->resp.gr_name_len = gr_name_len;
      data->resp.gr_passwd_len = gr_passwd_len;
      data->resp.gr_gid = grp->gr_gid;
      data->resp.gr_mem_cnt = gr_mem_cnt;

      cp = data->strdata;

      /* This is the member string length array.  */
      cp = mempcpy (cp, gr_mem_len, gr_mem_cnt * sizeof (uint32_t));
      gr_name = cp;
      cp = mempcpy (cp, grp->gr_name, gr_name_len);
      cp = mempcpy (cp, grp->gr_passwd, gr_passwd_len);

      for (cnt = 0; cnt < gr_mem_cnt; ++cnt)
	cp = mempcpy (cp, grp->gr_mem[cnt], gr_mem_len[cnt]);

      /* Finally the stringified GID value.  */
      memcpy (cp, buf, n);

      /* Write the result.  */
      written = TEMP_FAILURE_RETRY (write (fd, &data->resp, total));

      /* Compute the timeout time.  */
      t += db->postimeout;

      /* Now get the lock to safely insert the records.  */
      pthread_rwlock_rdlock (&db->lock);

      /* We have to add the value for both, byname and byuid.  */
      cache_add (GETGRBYNAME, gr_name, gr_name_len, data,
		 total, data, 0, t, db, owner);

      /* If the key is different from the name add a separate entry.  */
      if (type == GETGRBYNAME && strcmp (key, gr_name) != 0)
	cache_add (GETGRBYNAME, key, strlen (key) + 1, data,
		   total, data, 0, t, db, owner);

      cache_add (GETGRBYGID, cp, n, data, total, data, 1, t, db, owner);

      pthread_rwlock_unlock (&db->lock);
    }

  if (__builtin_expect (written != total, 0) && debug_level > 0)
    {
      char buf[256];
      dbg_log (_("short write in %s: %s"),  __FUNCTION__,
	       strerror_r (errno, buf, sizeof (buf)));
    }
}


void
addgrbyname (struct database *db, int fd, request_header *req,
	     void *key, uid_t uid)
{
  /* Search for the entry matching the key.  Please note that we don't
     look again in the table whether the dataset is now available.  We
     simply insert it.  It does not matter if it is in there twice.  The
     pruning function only will look at the timestamp.  */
  int buflen = 1024;
  char *buffer = (char *) alloca (buflen);
  struct group resultbuf;
  struct group *grp;
  uid_t oldeuid = 0;
  bool use_malloc = false;

  if (__builtin_expect (debug_level > 0, 0))
    dbg_log (_("Haven't found \"%s\" in group cache!"), (char *) key);

  if (secure[grpdb])
    {
      oldeuid = geteuid ();
      seteuid (uid);
    }

  while (__getgrnam_r (key, &resultbuf, buffer, buflen, &grp) != 0
	 && errno == ERANGE)
    {
      char *old_buffer = buffer;
      errno = 0;
#define INCR 1024

      if (__builtin_expect (buflen > 32768, 0))
	{
	  buflen += INCR;
	  buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen);
	  if (buffer == NULL)
	    {
	      /* We ran out of memory.  We cannot do anything but
		 sending a negative response.  In reality this should
		 never happen.  */
	      grp = NULL;
	      buffer = old_buffer;
	      break;
	    }
	  use_malloc = true;
	}
      else
	/* Allocate a new buffer on the stack.  If possible combine it
	   with the previously allocated buffer.  */
	buffer = (char *) extend_alloca (buffer, buflen, buflen + INCR);
    }

  if (secure[grpdb])
    seteuid (oldeuid);

  cache_addgr (db, fd, req, key, grp, uid, GETGRBYNAME);

  if (use_malloc)
    free (buffer);
}


void
addgrbygid (struct database *db, int fd, request_header *req,
	    void *key, uid_t uid)
{
  /* Search for the entry matching the key.  Please note that we don't
     look again in the table whether the dataset is now available.  We
     simply insert it.  It does not matter if it is in there twice.  The
     pruning function only will look at the timestamp.  */
  int buflen = 1024;
  char *buffer = (char *) alloca (buflen);
  struct group resultbuf;
  struct group *grp;
  uid_t oldeuid = 0;
  char *ep;
  gid_t gid = strtoul ((char *)key, &ep, 10);
  bool use_malloc = false;

  if (*(char *) key == '\0' || *ep != '\0')  /* invalid numeric gid */
    {
      if (debug_level > 0)
        dbg_log (_("Invalid numeric gid \"%s\"!"), (char *) key);

      errno = EINVAL;
      return;
    }

  if (__builtin_expect (debug_level > 0, 0))
    dbg_log (_("Haven't found \"%d\" in group cache!"), gid);

  if (secure[grpdb])
    {
      oldeuid = geteuid ();
      seteuid (uid);
    }

  while (__getgrgid_r (gid, &resultbuf, buffer, buflen, &grp) != 0
	 && errno == ERANGE)
    {
      char *old_buffer = buffer;
      errno = 0;

      if (__builtin_expect (buflen > 32768, 0))
	{
	  buflen += INCR;
	  buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen);
	  if (buffer == NULL)
	    {
	      /* We ran out of memory.  We cannot do anything but
		 sending a negative response.  In reality this should
		 never happen.  */
	      grp = NULL;
	      buffer = old_buffer;
	      break;
	    }
	  use_malloc = true;
	}
      else
	/* Allocate a new buffer on the stack.  If possible combine it
	   with the previously allocated buffer.  */
	buffer = (char *) extend_alloca (buffer, buflen, buflen + INCR);
    }

  if (secure[grpdb])
    seteuid (oldeuid);

  cache_addgr (db, fd, req, key, grp, uid, GETGRBYGID);

  if (use_malloc)
    free (buffer);
}