nscd/nscd_netgroup.c

   1 /* Copyright (C) 2011-2020 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <alloca.h>
  20 #include <errno.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <not-cancel.h>
  24
  25 #include "nscd-client.h"
  26 #include "nscd_proto.h"
  27
  28 int __nss_not_use_nscd_netgroup;
  29
  30
  31 libc_locked_map_ptr (static, map_handle);
  32 /* Note that we only free the structure if necessary.  The memory
  33    mapping is not removed since it is not visible to the malloc
  34    handling.  */
  35 libc_freeres_fn (pw_map_free)
  36 {
  37   if (map_handle.mapped != NO_MAPPING)
  38     {
  39       void *p = map_handle.mapped;
  40       map_handle.mapped = NO_MAPPING;
  41       free (p);
  42     }
  43 }
  44
  45
  46 int
  47 __nscd_setnetgrent (const char *group, struct __netgrent *datap)
  48 {
  49   int gc_cycle;
  50   int nretries = 0;
  51   size_t group_len = strlen (group) + 1;
  52
  53   /* If the mapping is available, try to search there instead of
  54      communicating with the nscd.  */
  55   struct mapped_database *mapped;
  56   mapped = __nscd_get_map_ref (GETFDNETGR, "netgroup", &map_handle, &gc_cycle);
  57
  58  retry:;
  59   char *respdata = NULL;
  60   int retval = -1;
  61   netgroup_response_header netgroup_resp;
  62
  63   if (mapped != NO_MAPPING)
  64     {
  65       struct datahead *found = __nscd_cache_search (GETNETGRENT, group,
  66                                                     group_len, mapped,
  67                                                     sizeof netgroup_resp);
  68       if (found != NULL)
  69         {
  70           respdata = (char *) (&found->data[0].netgroupdata + 1);
  71           netgroup_resp = found->data[0].netgroupdata;
  72           /* Now check if we can trust pw_resp fields.  If GC is
  73              in progress, it can contain anything.  */
  74           if (mapped->head->gc_cycle != gc_cycle)
  75             {
  76               retval = -2;
  77               goto out;
  78             }
  79         }
  80     }
  81
  82   int sock = -1;
  83   if (respdata == NULL)
  84     {
  85       sock = __nscd_open_socket (group, group_len, GETNETGRENT,
  86                                  &netgroup_resp, sizeof (netgroup_resp));
  87       if (sock == -1)
  88         {
  89           /* nscd not running or wrong version.  */
  90           __nss_not_use_nscd_netgroup = 1;
  91           goto out;
  92         }
  93     }
  94
  95   if (netgroup_resp.found == 1)
  96     {
  97       size_t datalen = netgroup_resp.result_len;
  98
  99       /* If we do not have to read the data here it comes from the
 100          mapped data and does not have to be freed.  */
 101       if (respdata == NULL)
 102         {
 103           /* The data will come via the socket.  */
 104           respdata = malloc (datalen);
 105           if (respdata == NULL)
 106             goto out_close;
 107
 108           if ((size_t) __readall (sock, respdata, datalen) != datalen)
 109             {
 110               free (respdata);
 111               goto out_close;
 112             }
 113         }
 114
 115       datap->data = respdata;
 116       datap->data_size = datalen;
 117       datap->cursor = respdata;
 118       datap->first = 1;
 119       datap->nip = (service_user *) -1l;
 120       datap->known_groups = NULL;
 121       datap->needed_groups = NULL;
 122
 123       retval = 1;
 124     }
 125   else
 126     {
 127       if (__glibc_unlikely (netgroup_resp.found == -1))
 128         {
 129           /* The daemon does not cache this database.  */
 130           __nss_not_use_nscd_netgroup = 1;
 131           goto out_close;
 132         }
 133
 134       /* Set errno to 0 to indicate no error, just no found record.  */
 135       __set_errno (0);
 136       /* Even though we have not found anything, the result is zero.  */
 137       retval = 0;
 138     }
 139
 140  out_close:
 141   if (sock != -1)
 142     __close_nocancel_nostatus (sock);
 143  out:
 144   if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0)
 145     {
 146       /* When we come here this means there has been a GC cycle while we
 147          were looking for the data.  This means the data might have been
 148          inconsistent.  Retry if possible.  */
 149       if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1)
 150         {
 151           /* nscd is just running gc now.  Disable using the mapping.  */
 152           if (atomic_decrement_val (&mapped->counter) == 0)
 153             __nscd_unmap (mapped);
 154           mapped = NO_MAPPING;
 155         }
 156
 157       if (retval != -1)
 158         goto retry;
 159     }
 160
 161   return retval;
 162 }
 163
 164
 165 int
 166 __nscd_innetgr (const char *netgroup, const char *host, const char *user,
 167                 const char *domain)
 168 {
 169   size_t key_len = (strlen (netgroup) + strlen (host ?: "")
 170                     + strlen (user ?: "") + strlen (domain ?: "") + 7);
 171   char *key;
 172   bool use_alloca = __libc_use_alloca (key_len);
 173   if (use_alloca)
 174     key = alloca (key_len);
 175   else
 176     {
 177       key = malloc (key_len);
 178       if (key == NULL)
 179         return -1;
 180     }
 181   char *wp = stpcpy (key, netgroup) + 1;
 182   if (host != NULL)
 183     {
 184       *wp++ = '\1';
 185       wp = stpcpy (wp, host) + 1;
 186     }
 187   else
 188     *wp++ = '\0';
 189   if (user != NULL)
 190     {
 191       *wp++ = '\1';
 192       wp = stpcpy (wp, user) + 1;
 193     }
 194   else
 195     *wp++ = '\0';
 196   if (domain != NULL)
 197     {
 198       *wp++ = '\1';
 199       wp = stpcpy (wp, domain) + 1;
 200     }
 201   else
 202     *wp++ = '\0';
 203   key_len = wp - key;
 204
 205   /* If the mapping is available, try to search there instead of
 206      communicating with the nscd.  */
 207   int gc_cycle;
 208   int nretries = 0;
 209   struct mapped_database *mapped;
 210   mapped = __nscd_get_map_ref (GETFDNETGR, "netgroup", &map_handle, &gc_cycle);
 211
 212  retry:;
 213   int retval = -1;
 214   innetgroup_response_header innetgroup_resp;
 215   int sock = -1;
 216
 217   if (mapped != NO_MAPPING)
 218     {
 219       struct datahead *found = __nscd_cache_search (INNETGR, key,
 220                                                     key_len, mapped,
 221                                                     sizeof innetgroup_resp);
 222       if (found != NULL)
 223         {
 224           innetgroup_resp = found->data[0].innetgroupdata;
 225           /* Now check if we can trust pw_resp fields.  If GC is
 226              in progress, it can contain anything.  */
 227           if (mapped->head->gc_cycle != gc_cycle)
 228             {
 229               retval = -2;
 230               goto out;
 231             }
 232
 233           goto found_entry;
 234         }
 235     }
 236
 237   sock = __nscd_open_socket (key, key_len, INNETGR,
 238                              &innetgroup_resp, sizeof (innetgroup_resp));
 239   if (sock == -1)
 240     {
 241       /* nscd not running or wrong version.  */
 242       __nss_not_use_nscd_netgroup = 1;
 243       goto out;
 244     }
 245
 246  found_entry:
 247   if (innetgroup_resp.found == 1)
 248     retval = innetgroup_resp.result;
 249   else
 250     {
 251       if (__glibc_unlikely (innetgroup_resp.found == -1))
 252         {
 253           /* The daemon does not cache this database.  */
 254           __nss_not_use_nscd_netgroup = 1;
 255           goto out_close;
 256         }
 257
 258       /* Set errno to 0 to indicate no error, just no found record.  */
 259       __set_errno (0);
 260       /* Even though we have not found anything, the result is zero.  */
 261       retval = 0;
 262     }
 263
 264  out_close:
 265   if (sock != -1)
 266     __close_nocancel_nostatus (sock);
 267  out:
 268   if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0)
 269     {
 270       /* When we come here this means there has been a GC cycle while we
 271          were looking for the data.  This means the data might have been
 272          inconsistent.  Retry if possible.  */
 273       if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1)
 274         {
 275           /* nscd is just running gc now.  Disable using the mapping.  */
 276           if (atomic_decrement_val (&mapped->counter) == 0)
 277             __nscd_unmap (mapped);
 278           mapped = NO_MAPPING;
 279         }
 280
 281       if (retval != -1)
 282         goto retry;
 283     }
 284
 285   if (! use_alloca)
 286     free (key);
 287
 288   return retval;
 289 }