nscd/nscd_netgroup.c

   1 /* Copyright (C) 2011-2022 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <alloca.h>
  19 #include <errno.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <not-cancel.h>
  23
  24 #include "nscd-client.h"
  25 #include "nscd_proto.h"
  26
  27 int __nss_not_use_nscd_netgroup;
  28
  29
  30 libc_locked_map_ptr (static, map_handle);
  31 /* Note that we only free the structure if necessary.  The memory
  32    mapping is not removed since it is not visible to the malloc
  33    handling.  */
  34 libc_freeres_fn (pw_map_free)
  35 {
  36   if (map_handle.mapped != NO_MAPPING)
  37     {
  38       void *p = map_handle.mapped;
  39       map_handle.mapped = NO_MAPPING;
  40       free (p);
  41     }
  42 }
  43
  44
  45 int
  46 __nscd_setnetgrent (const char *group, struct __netgrent *datap)
  47 {
  48   int gc_cycle;
  49   int nretries = 0;
  50   size_t group_len = strlen (group) + 1;
  51
  52   /* If the mapping is available, try to search there instead of
  53      communicating with the nscd.  */
  54   struct mapped_database *mapped;
  55   mapped = __nscd_get_map_ref (GETFDNETGR, "netgroup", &map_handle, &gc_cycle);
  56
  57  retry:;
  58   char *respdata = NULL;
  59   int retval = -1;
  60   netgroup_response_header netgroup_resp;
  61
  62   if (mapped != NO_MAPPING)
  63     {
  64       struct datahead *found = __nscd_cache_search (GETNETGRENT, group,
  65                                                     group_len, mapped,
  66                                                     sizeof netgroup_resp);
  67       if (found != NULL)
  68         {
  69           respdata = (char *) (&found->data[0].netgroupdata + 1);
  70           netgroup_resp = found->data[0].netgroupdata;
  71           /* Now check if we can trust pw_resp fields.  If GC is
  72              in progress, it can contain anything.  */
  73           if (mapped->head->gc_cycle != gc_cycle)
  74             {
  75               retval = -2;
  76               goto out;
  77             }
  78         }
  79     }
  80
  81   int sock = -1;
  82   if (respdata == NULL)
  83     {
  84       sock = __nscd_open_socket (group, group_len, GETNETGRENT,
  85                                  &netgroup_resp, sizeof (netgroup_resp));
  86       if (sock == -1)
  87         {
  88           /* nscd not running or wrong version.  */
  89           __nss_not_use_nscd_netgroup = 1;
  90           goto out;
  91         }
  92     }
  93
  94   if (netgroup_resp.found == 1)
  95     {
  96       size_t datalen = netgroup_resp.result_len;
  97
  98       /* If we do not have to read the data here it comes from the
  99          mapped data and does not have to be freed.  */
 100       if (respdata == NULL)
 101         {
 102           /* The data will come via the socket.  */
 103           respdata = malloc (datalen);
 104           if (respdata == NULL)
 105             goto out_close;
 106
 107           if ((size_t) __readall (sock, respdata, datalen) != datalen)
 108             {
 109               free (respdata);
 110               goto out_close;
 111             }
 112         }
 113
 114       datap->data = respdata;
 115       datap->data_size = datalen;
 116       datap->cursor = respdata;
 117       datap->first = 1;
 118       datap->nip = (nss_action_list) -1l;
 119       datap->known_groups = NULL;
 120       datap->needed_groups = NULL;
 121
 122       retval = 1;
 123     }
 124   else
 125     {
 126       if (__glibc_unlikely (netgroup_resp.found == -1))
 127         {
 128           /* The daemon does not cache this database.  */
 129           __nss_not_use_nscd_netgroup = 1;
 130           goto out_close;
 131         }
 132
 133       /* Set errno to 0 to indicate no error, just no found record.  */
 134       __set_errno (0);
 135       /* Even though we have not found anything, the result is zero.  */
 136       retval = 0;
 137     }
 138
 139  out_close:
 140   if (sock != -1)
 141     __close_nocancel_nostatus (sock);
 142  out:
 143   if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0)
 144     {
 145       /* When we come here this means there has been a GC cycle while we
 146          were looking for the data.  This means the data might have been
 147          inconsistent.  Retry if possible.  */
 148       if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1)
 149         {
 150           /* nscd is just running gc now.  Disable using the mapping.  */
 151           if (atomic_decrement_val (&mapped->counter) == 0)
 152             __nscd_unmap (mapped);
 153           mapped = NO_MAPPING;
 154         }
 155
 156       if (retval != -1)
 157         goto retry;
 158     }
 159
 160   return retval;
 161 }
 162
 163
 164 int
 165 __nscd_innetgr (const char *netgroup, const char *host, const char *user,
 166                 const char *domain)
 167 {
 168   size_t key_len = (strlen (netgroup) + strlen (host ?: "")
 169                     + strlen (user ?: "") + strlen (domain ?: "") + 7);
 170   char *key;
 171   bool use_alloca = __libc_use_alloca (key_len);
 172   if (use_alloca)
 173     key = alloca (key_len);
 174   else
 175     {
 176       key = malloc (key_len);
 177       if (key == NULL)
 178         return -1;
 179     }
 180   char *wp = stpcpy (key, netgroup) + 1;
 181   if (host != NULL)
 182     {
 183       *wp++ = '\1';
 184       wp = stpcpy (wp, host) + 1;
 185     }
 186   else
 187     *wp++ = '\0';
 188   if (user != NULL)
 189     {
 190       *wp++ = '\1';
 191       wp = stpcpy (wp, user) + 1;
 192     }
 193   else
 194     *wp++ = '\0';
 195   if (domain != NULL)
 196     {
 197       *wp++ = '\1';
 198       wp = stpcpy (wp, domain) + 1;
 199     }
 200   else
 201     *wp++ = '\0';
 202   key_len = wp - key;
 203
 204   /* If the mapping is available, try to search there instead of
 205      communicating with the nscd.  */
 206   int gc_cycle;
 207   int nretries = 0;
 208   struct mapped_database *mapped;
 209   mapped = __nscd_get_map_ref (GETFDNETGR, "netgroup", &map_handle, &gc_cycle);
 210
 211  retry:;
 212   int retval = -1;
 213   innetgroup_response_header innetgroup_resp;
 214   int sock = -1;
 215
 216   if (mapped != NO_MAPPING)
 217     {
 218       struct datahead *found = __nscd_cache_search (INNETGR, key,
 219                                                     key_len, mapped,
 220                                                     sizeof innetgroup_resp);
 221       if (found != NULL)
 222         {
 223           innetgroup_resp = found->data[0].innetgroupdata;
 224           /* Now check if we can trust pw_resp fields.  If GC is
 225              in progress, it can contain anything.  */
 226           if (mapped->head->gc_cycle != gc_cycle)
 227             {
 228               retval = -2;
 229               goto out;
 230             }
 231
 232           goto found_entry;
 233         }
 234     }
 235
 236   sock = __nscd_open_socket (key, key_len, INNETGR,
 237                              &innetgroup_resp, sizeof (innetgroup_resp));
 238   if (sock == -1)
 239     {
 240       /* nscd not running or wrong version.  */
 241       __nss_not_use_nscd_netgroup = 1;
 242       goto out;
 243     }
 244
 245  found_entry:
 246   if (innetgroup_resp.found == 1)
 247     retval = innetgroup_resp.result;
 248   else
 249     {
 250       if (__glibc_unlikely (innetgroup_resp.found == -1))
 251         {
 252           /* The daemon does not cache this database.  */
 253           __nss_not_use_nscd_netgroup = 1;
 254           goto out_close;
 255         }
 256
 257       /* Set errno to 0 to indicate no error, just no found record.  */
 258       __set_errno (0);
 259       /* Even though we have not found anything, the result is zero.  */
 260       retval = 0;
 261     }
 262
 263  out_close:
 264   if (sock != -1)
 265     __close_nocancel_nostatus (sock);
 266  out:
 267   if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0)
 268     {
 269       /* When we come here this means there has been a GC cycle while we
 270          were looking for the data.  This means the data might have been
 271          inconsistent.  Retry if possible.  */
 272       if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1)
 273         {
 274           /* nscd is just running gc now.  Disable using the mapping.  */
 275           if (atomic_decrement_val (&mapped->counter) == 0)
 276             __nscd_unmap (mapped);
 277           mapped = NO_MAPPING;
 278         }
 279
 280       if (retval != -1)
 281         goto retry;
 282     }
 283
 284   if (! use_alloca)
 285     free (key);
 286
 287   return retval;
 288 }