nis/nss_nisplus/nisplus-initgroups.c

   1 /* Copyright (C) 1997-2016 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    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <atomic.h>
  19 #include <nss.h>
  20 #include <grp.h>
  21 #include <ctype.h>
  22 #include <errno.h>
  23 #include <string.h>
  24 #include <libc-lock.h>
  25 #include <rpcsvc/nis.h>
  26
  27 #include "nss-nisplus.h"
  28 #include "nisplus-parser.h"
  29 #include <libnsl.h>
  30 #include <nis_intern.h>
  31 #include <nis_xdr.h>
  32
  33 #define NISOBJVAL(col, obj) \
  34   ((obj)->EN_data.en_cols.en_cols_val[col].ec_value.ec_value_val)
  35
  36 #define NISOBJLEN(col, obj) \
  37   ((obj)->EN_data.en_cols.en_cols_val[col].ec_value.ec_value_len)
  38
  39 extern nis_name grp_tablename_val attribute_hidden;
  40 extern size_t grp_tablename_len attribute_hidden;
  41 extern enum nss_status _nss_grp_create_tablename (int *errnop);
  42
  43
  44 enum nss_status
  45 _nss_nisplus_initgroups_dyn (const char *user, gid_t group, long int *start,
  46                              long int *size, gid_t **groupsp, long int limit,
  47                              int *errnop)
  48 {
  49   if (grp_tablename_val == NULL)
  50     {
  51       enum nss_status status = _nss_grp_create_tablename (errnop);
  52
  53       if (status != NSS_STATUS_SUCCESS)
  54         return status;
  55     }
  56
  57   nis_result *result;
  58   char buf[strlen (user) + 12 + grp_tablename_len];
  59
  60   snprintf (buf, sizeof (buf), "[members=%s],%s", user, grp_tablename_val);
  61
  62   result = nis_list (buf, FOLLOW_LINKS | FOLLOW_PATH | ALL_RESULTS, NULL, NULL);
  63
  64   if (result == NULL)
  65     {
  66       *errnop = ENOMEM;
  67       return NSS_STATUS_TRYAGAIN;
  68     }
  69
  70   if (__glibc_unlikely (niserr2nss (result->status) != NSS_STATUS_SUCCESS))
  71     {
  72       enum nss_status status = niserr2nss (result->status);
  73
  74       nis_freeresult (result);
  75       return status;
  76     }
  77
  78   if (NIS_RES_NUMOBJ (result) == 0)
  79     {
  80     errout:
  81       nis_freeresult (result);
  82       return NSS_STATUS_NOTFOUND;
  83     }
  84
  85   gid_t *groups = *groupsp;
  86   nis_object *obj = NIS_RES_OBJECT (result);
  87   for (unsigned int cnt = 0; cnt < NIS_RES_NUMOBJ (result); ++cnt, ++obj)
  88     {
  89       if (__type_of (obj) != NIS_ENTRY_OBJ
  90           || strcmp (obj->EN_data.en_type, "group_tbl") != 0
  91           || obj->EN_data.en_cols.en_cols_len < 4)
  92         continue;
  93
  94       char *numstr = NISOBJVAL (2, obj);
  95       size_t len = NISOBJLEN (2, obj);
  96       if (len == 0 || numstr[0] == '\0')
  97         continue;
  98
  99       gid_t gid;
 100       char *endp;
 101       if (__glibc_unlikely (numstr[len - 1] != '\0'))
 102         {
 103           char numstrbuf[len + 1];
 104           memcpy (numstrbuf, numstr, len);
 105           numstrbuf[len] = '\0';
 106           gid = strtoul (numstrbuf, &endp, 10);
 107           if (*endp)
 108             continue;
 109         }
 110       else
 111         {
 112           gid = strtoul (numstr, &endp, 10);
 113           if (*endp)
 114             continue;
 115         }
 116
 117       if (gid == group)
 118         continue;
 119
 120       /* Insert this group.  */
 121       if (*start == *size)
 122         {
 123           /* Need a bigger buffer.  */
 124           long int newsize;
 125
 126           if (limit > 0 && *size == limit)
 127             /* We reached the maximum.  */
 128             break;
 129
 130           if (limit <= 0)
 131             newsize = 2 * *size;
 132           else
 133             newsize = MIN (limit, 2 * *size);
 134
 135           gid_t *newgroups = realloc (groups, newsize * sizeof (*groups));
 136           if (newgroups == NULL)
 137             goto errout;
 138           *groupsp = groups = newgroups;
 139           *size = newsize;
 140         }
 141
 142       groups[*start] = gid;
 143       *start += 1;
 144     }
 145
 146   nis_freeresult (result);
 147   return NSS_STATUS_SUCCESS;
 148 }