nis/nss_nis/nis-initgroups.c

   1 /* Copyright (C) 1998-2013 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Thorsten Kukuk <kukuk@suse.de>, 1998.
   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    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <alloca.h>
  20 #include <ctype.h>
  21 #include <errno.h>
  22 #include <grp.h>
  23 #include <nss.h>
  24 #include <pwd.h>
  25 #include <string.h>
  26 #include <unistd.h>
  27 #include <rpcsvc/yp.h>
  28 #include <rpcsvc/ypclnt.h>
  29 #include <sys/param.h>
  30
  31 #include "nss-nis.h"
  32 #include <libnsl.h>
  33
  34 /* Get the declaration of the parser function.  */
  35 #define ENTNAME grent
  36 #define STRUCTURE group
  37 #define EXTERN_PARSER
  38 #include <nss/nss_files/files-parse.c>
  39
  40
  41 static enum nss_status
  42 internal_setgrent (char *domainname, intern_t *intern)
  43 {
  44   struct ypall_callback ypcb;
  45   enum nss_status status;
  46
  47   ypcb.foreach = _nis_saveit;
  48   ypcb.data = (char *) intern;
  49   status = yperr2nss (yp_all (domainname, "group.byname", &ypcb));
  50
  51   /* Mark the last buffer as full.  */
  52   if (intern->next != NULL)
  53     intern->next->size = intern->offset;
  54
  55   intern->next = intern->start;
  56   intern->offset = 0;
  57
  58   return status;
  59 }
  60
  61
  62 static enum nss_status
  63 internal_getgrent_r (struct group *grp, char *buffer, size_t buflen,
  64                      int *errnop, intern_t *intern)
  65 {
  66   if (intern->start == NULL)
  67     return NSS_STATUS_NOTFOUND;
  68
  69   /* Get the next entry until we found a correct one. */
  70   int parse_res;
  71   do
  72     {
  73       struct response_t *bucket = intern->next;
  74
  75       if (__builtin_expect (intern->offset >= bucket->size, 0))
  76         {
  77           if (bucket->next == NULL)
  78             return NSS_STATUS_NOTFOUND;
  79
  80           /* We look at all the content in the current bucket.  Go on
  81              to the next.  */
  82           bucket = intern->next = bucket->next;
  83           intern->offset = 0;
  84         }
  85
  86       char *p;
  87       for (p = &bucket->mem[intern->offset]; isspace (*p); ++p)
  88         ++intern->offset;
  89
  90       size_t len = strlen (p) + 1;
  91       if (__builtin_expect (len > buflen, 0))
  92         {
  93           *errnop = ERANGE;
  94           return NSS_STATUS_TRYAGAIN;
  95         }
  96
  97       /* We unfortunately have to copy the data in the user-provided
  98          buffer because that buffer might be around for a very long
  99          time and the servent structure must remain valid.  If we would
 100          rely on the BUCKET memory the next 'setservent' or 'endservent'
 101          call would destroy it.
 102
 103          The important thing is that it is a single NUL-terminated
 104          string.  This is what the parsing routine expects.  */
 105       p = memcpy (buffer, &bucket->mem[intern->offset], len);
 106
 107       parse_res = _nss_files_parse_grent (p, grp, (void *) buffer, buflen,
 108                                           errnop);
 109       if (__builtin_expect (parse_res == -1, 0))
 110         return NSS_STATUS_TRYAGAIN;
 111
 112       intern->offset += len;
 113     }
 114   while (!parse_res);
 115
 116   return NSS_STATUS_SUCCESS;
 117 }
 118
 119
 120 static int
 121 get_uid (const char *user, uid_t *uidp)
 122 {
 123   size_t buflen = sysconf (_SC_GETPW_R_SIZE_MAX);
 124   char *buf = (char *) alloca (buflen);
 125
 126   while (1)
 127     {
 128       struct passwd result;
 129       struct passwd *resp;
 130
 131       int r = getpwnam_r (user, &result, buf, buflen, &resp);
 132       if (r == 0 && resp != NULL)
 133         {
 134           *uidp = resp->pw_uid;
 135           return 0;
 136         }
 137
 138       if (r != ERANGE)
 139         break;
 140
 141       buf = extend_alloca (buf, buflen, 2 * buflen);
 142     }
 143
 144   return 1;
 145 }
 146
 147
 148 static enum nss_status
 149 initgroups_netid (uid_t uid, gid_t group, long int *start, long int *size,
 150                   gid_t **groupsp, long int limit, int *errnop,
 151                   const char *domainname)
 152 {
 153   /* Prepare the key.  The form is "unix.UID@DOMAIN" with the UID and
 154      DOMAIN field filled in appropriately.  */
 155   char key[sizeof ("unix.@") + sizeof (uid_t) * 3 + strlen (domainname)];
 156   ssize_t keylen = snprintf (key, sizeof (key), "unix.%lu@%s",
 157                              (unsigned long int) uid, domainname);
 158
 159   char *result;
 160   int reslen;
 161   int yperr = yp_match (domainname, "netid.byname", key, keylen, &result,
 162                         &reslen);
 163   if (__builtin_expect (yperr != YPERR_SUCCESS, 0))
 164     return yperr2nss (yperr);
 165
 166   /* Parse the result: following the colon is a comma separated list of
 167      group IDs.  */
 168   char *cp = strchr (result, ':');
 169   if (cp == NULL)
 170     {
 171     errout:
 172       free (result);
 173       return NSS_STATUS_NOTFOUND;
 174     }
 175   /* Skip the colon.  */
 176   ++cp;
 177
 178   gid_t *groups = *groupsp;
 179   while (*cp != '\0')
 180     {
 181       char *endp;
 182       unsigned long int gid = strtoul (cp, &endp, 0);
 183       if (cp == endp)
 184         goto errout;
 185       if (*endp == ',')
 186         ++endp;
 187       else if (*endp != '\0')
 188         goto errout;
 189       cp = endp;
 190
 191       if (gid == group)
 192         /* We do not need this group again.  */
 193         continue;
 194
 195       /* Insert this group.  */
 196       if (*start == *size)
 197         {
 198           /* Need a bigger buffer.  */
 199           long int newsize;
 200
 201           if (limit > 0 && *size == limit)
 202             /* We reached the maximum.  */
 203             break;
 204
 205           if (limit <= 0)
 206             newsize = 2 * *size;
 207           else
 208             newsize = MIN (limit, 2 * *size);
 209
 210           gid_t *newgroups = realloc (groups, newsize * sizeof (*groups));
 211           if (newgroups == NULL)
 212             goto errout;
 213           *groupsp = groups = newgroups;
 214           *size = newsize;
 215         }
 216
 217       groups[*start] = gid;
 218       *start += 1;
 219     }
 220
 221   free (result);
 222
 223   return NSS_STATUS_SUCCESS;
 224 }
 225
 226
 227 enum nss_status
 228 _nss_nis_initgroups_dyn (const char *user, gid_t group, long int *start,
 229                          long int *size, gid_t **groupsp, long int limit,
 230                          int *errnop)
 231 {
 232   /* We always need the domain name.  */
 233   char *domainname;
 234   if (yp_get_default_domain (&domainname))
 235     return NSS_STATUS_UNAVAIL;
 236
 237   /* Check whether we are supposed to use the netid.byname map.  */
 238   if (_nsl_default_nss () & NSS_FLAG_NETID_AUTHORITATIVE)
 239     {
 240       /* We need the user ID.  */
 241       uid_t uid;
 242
 243       if (get_uid (user, &uid) == 0
 244           && initgroups_netid (uid, group, start, size, groupsp, limit,
 245                                errnop, domainname) == NSS_STATUS_SUCCESS)
 246         return NSS_STATUS_SUCCESS;
 247     }
 248
 249   struct group grpbuf, *g;
 250   size_t buflen = sysconf (_SC_GETPW_R_SIZE_MAX);
 251   char *tmpbuf;
 252   enum nss_status status;
 253   intern_t intern = { NULL, NULL, 0 };
 254   gid_t *groups = *groupsp;
 255
 256   status = internal_setgrent (domainname, &intern);
 257   if (status != NSS_STATUS_SUCCESS)
 258     return status;
 259
 260   tmpbuf = __alloca (buflen);
 261
 262   do
 263     {
 264       while ((status =
 265               internal_getgrent_r (&grpbuf, tmpbuf, buflen, errnop,
 266                                    &intern)) == NSS_STATUS_TRYAGAIN
 267              && *errnop == ERANGE)
 268         tmpbuf = extend_alloca (tmpbuf, buflen, 2 * buflen);
 269
 270       if (status != NSS_STATUS_SUCCESS)
 271         goto done;
 272
 273
 274       g = &grpbuf;
 275       if (g->gr_gid != group)
 276         {
 277           char **m;
 278
 279           for (m = g->gr_mem; *m != NULL; ++m)
 280             if (strcmp (*m, user) == 0)
 281               {
 282                 /* Matches user.  Insert this group.  */
 283                 if (*start == *size)
 284                   {
 285                     /* Need a bigger buffer.  */
 286                     gid_t *newgroups;
 287                     long int newsize;
 288
 289                     if (limit > 0 && *size == limit)
 290                       /* We reached the maximum.  */
 291                       goto done;
 292
 293                     if (limit <= 0)
 294                       newsize = 2 * *size;
 295                     else
 296                       newsize = MIN (limit, 2 * *size);
 297
 298                     newgroups = realloc (groups, newsize * sizeof (*groups));
 299                     if (newgroups == NULL)
 300                       goto done;
 301                     *groupsp = groups = newgroups;
 302                     *size = newsize;
 303                   }
 304
 305                 groups[*start] = g->gr_gid;
 306                 *start += 1;
 307
 308                 break;
 309               }
 310         }
 311     }
 312   while (status == NSS_STATUS_SUCCESS);
 313
 314 done:
 315   while (intern.start != NULL)
 316     {
 317       intern.next = intern.start;
 318       intern.start = intern.start->next;
 319       free (intern.next);
 320     }
 321
 322   return NSS_STATUS_SUCCESS;
 323 }