hesiod/nss_hesiod/hesiod-grp.c

   1 /* Copyright (C) 1997-2023 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 <ctype.h>
  19 #include <errno.h>
  20 #include <grp.h>
  21 #include <hesiod.h>
  22 #include <nss.h>
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <sys/param.h>
  27
  28 NSS_DECLARE_MODULE_FUNCTIONS (hesiod)
  29
  30 /* Get the declaration of the parser function.  */
  31 #define ENTNAME grent
  32 #define STRUCTURE group
  33 #define EXTERN_PARSER
  34 #include <nss/nss_files/files-parse.c>
  35
  36 enum nss_status
  37 _nss_hesiod_setgrent (int stayopen)
  38 {
  39   return NSS_STATUS_SUCCESS;
  40 }
  41
  42 enum nss_status
  43 _nss_hesiod_endgrent (void)
  44 {
  45   return NSS_STATUS_SUCCESS;
  46 }
  47
  48 static enum nss_status
  49 lookup (const char *name, const char *type, struct group *grp,
  50         char *buffer, size_t buflen, int *errnop)
  51 {
  52   struct parser_data *data = (void *) buffer;
  53   size_t linebuflen;
  54   void *context;
  55   char **list;
  56   int parse_res;
  57   size_t len;
  58   int olderr = errno;
  59
  60   if (hesiod_init (&context) < 0)
  61     return NSS_STATUS_UNAVAIL;
  62
  63   list = hesiod_resolve (context, name, type);
  64   if (list == NULL)
  65     {
  66       int err = errno;
  67       hesiod_end (context);
  68       __set_errno (olderr);
  69       return err == ENOENT ? NSS_STATUS_NOTFOUND : NSS_STATUS_UNAVAIL;
  70     }
  71
  72   linebuflen = buffer + buflen - data->linebuffer;
  73   len = strlen (*list) + 1;
  74   if (linebuflen < len)
  75     {
  76       hesiod_free_list (context, list);
  77       hesiod_end (context);
  78       *errnop = ERANGE;
  79       return NSS_STATUS_TRYAGAIN;
  80     }
  81
  82   memcpy (data->linebuffer, *list, len);
  83   hesiod_free_list (context, list);
  84   hesiod_end (context);
  85
  86   parse_res = _nss_files_parse_grent (buffer, grp, data, buflen, errnop);
  87   if (parse_res < 1)
  88     {
  89       __set_errno (olderr);
  90       return parse_res == -1 ? NSS_STATUS_TRYAGAIN : NSS_STATUS_NOTFOUND;
  91     }
  92
  93   return NSS_STATUS_SUCCESS;
  94 }
  95
  96 enum nss_status
  97 _nss_hesiod_getgrnam_r (const char *name, struct group *grp,
  98                         char *buffer, size_t buflen, int *errnop)
  99 {
 100   return lookup (name, "group", grp, buffer, buflen, errnop);
 101 }
 102
 103 enum nss_status
 104 _nss_hesiod_getgrgid_r (gid_t gid, struct group *grp,
 105                         char *buffer, size_t buflen, int *errnop)
 106 {
 107   char gidstr[21];      /* We will probably never have a gid_t with more
 108                            than 64 bits.  */
 109
 110   snprintf (gidstr, sizeof gidstr, "%d", gid);
 111
 112   return lookup (gidstr, "gid", grp, buffer, buflen, errnop);
 113 }
 114
 115 static int
 116 internal_gid_in_list (const gid_t *list, const gid_t g, long int len)
 117 {
 118   while (len > 0)
 119     {
 120       if (*list == g)
 121         return 1;
 122       --len;
 123       ++list;
 124     }
 125   return 0;
 126 }
 127
 128 static enum nss_status
 129 internal_gid_from_group (void *context, const char *groupname, gid_t *group)
 130 {
 131   char **grp_res;
 132   enum nss_status status = NSS_STATUS_NOTFOUND;
 133
 134   grp_res = hesiod_resolve (context, groupname, "group");
 135   if (grp_res != NULL && *grp_res != NULL)
 136     {
 137       char *p = *grp_res;
 138
 139       /* Skip to third field.  */
 140       while (*p != '\0' && *p != ':')
 141         ++p;
 142       if (*p != '\0')
 143         ++p;
 144       while (*p != '\0' && *p != ':')
 145         ++p;
 146       if (*p != '\0')
 147         {
 148           char *endp;
 149           char *q = ++p;
 150           long int val;
 151
 152           while (*q != '\0' && *q != ':')
 153             ++q;
 154
 155           val = strtol (p, &endp, 10);
 156           if (sizeof (gid_t) == sizeof (long int) || (gid_t) val == val)
 157             {
 158               *group = val;
 159               if (endp == q && endp != p)
 160                 status = NSS_STATUS_SUCCESS;
 161             }
 162         }
 163       hesiod_free_list (context, grp_res);
 164     }
 165   return status;
 166 }
 167
 168 enum nss_status
 169 _nss_hesiod_initgroups_dyn (const char *user, gid_t group, long int *start,
 170                             long int *size, gid_t **groupsp, long int limit,
 171                             int *errnop)
 172 {
 173   enum nss_status status = NSS_STATUS_SUCCESS;
 174   char **list = NULL;
 175   char *p;
 176   void *context;
 177   gid_t *groups = *groupsp;
 178   int save_errno;
 179
 180   if (hesiod_init (&context) < 0)
 181     return NSS_STATUS_UNAVAIL;
 182
 183   list = hesiod_resolve (context, user, "grplist");
 184
 185   if (list == NULL)
 186     {
 187       hesiod_end (context);
 188       return errno == ENOENT ? NSS_STATUS_NOTFOUND : NSS_STATUS_UNAVAIL;
 189     }
 190
 191   save_errno = errno;
 192
 193   p = *list;
 194   while (*p != '\0')
 195     {
 196       char *endp;
 197       char *q;
 198       long int val;
 199
 200       status = NSS_STATUS_NOTFOUND;
 201
 202       q = p;
 203       while (*q != '\0' && *q != ':' && *q != ',')
 204         ++q;
 205
 206       if (*q != '\0')
 207         *q++ = '\0';
 208
 209       __set_errno (0);
 210       val = strtol (p, &endp, 10);
 211       /* Test whether the number is representable in a variable of
 212          type `gid_t'.  If not ignore the number.  */
 213       if ((sizeof (gid_t) == sizeof (long int) || (gid_t) val == val)
 214           && errno == 0)
 215         {
 216           if (*endp == '\0' && endp != p)
 217             {
 218               group = val;
 219               status = NSS_STATUS_SUCCESS;
 220             }
 221           else
 222             status = internal_gid_from_group (context, p, &group);
 223
 224           if (status == NSS_STATUS_SUCCESS
 225               && !internal_gid_in_list (groups, group, *start))
 226             {
 227               if (__glibc_unlikely (*start == *size))
 228                 {
 229                   /* Need a bigger buffer.  */
 230                   gid_t *newgroups;
 231                   long int newsize;
 232
 233                   if (limit > 0 && *size == limit)
 234                     /* We reached the maximum.  */
 235                     goto done;
 236
 237                   if (limit <= 0)
 238                     newsize = 2 * *size;
 239                   else
 240                     newsize = MIN (limit, 2 * *size);
 241
 242                   newgroups = realloc (groups, newsize * sizeof (*groups));
 243                   if (newgroups == NULL)
 244                     goto done;
 245                   *groupsp = groups = newgroups;
 246                   *size = newsize;
 247                 }
 248
 249               groups[(*start)++] = group;
 250             }
 251         }
 252
 253       p = q;
 254     }
 255
 256   __set_errno (save_errno);
 257
 258  done:
 259   hesiod_free_list (context, list);
 260   hesiod_end (context);
 261
 262   return NSS_STATUS_SUCCESS;
 263 }