source/lib/system_smbd.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    system call wrapper interface.
   4    Copyright (C) Andrew Tridgell 2002
   5    Copyright (C) Andrew Barteltt 2002
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 /*
  23    This file may assume linkage with smbd - for things like become_root()
  24    etc.
  25 */
  26
  27 #include "includes.h"
  28
  29 #ifndef HAVE_GETGROUPLIST
  30
  31 /*
  32   This is a *much* faster way of getting the list of groups for a user
  33   without changing the current supplementary group list. The old
  34   method used getgrent() which could take 20 minutes on a really big
  35   network with hundeds of thousands of groups and users. The new method
  36   takes a couple of seconds.
  37
  38   NOTE!! this function only works if it is called as root!
  39   */
  40
  41 static int getgrouplist_internals(const char *user, gid_t gid, gid_t *groups,
  42                                   int *grpcnt)
  43 {
  44         gid_t *gids_saved;
  45         int ret, ngrp_saved, num_gids;
  46
  47         if (non_root_mode()) {
  48                 *grpcnt = 0;
  49                 return 0;
  50         }
  51
  52         /* work out how many groups we need to save */
  53         ngrp_saved = getgroups(0, NULL);
  54         if (ngrp_saved == -1) {
  55                 /* this shouldn't happen */
  56                 return -1;
  57         }
  58
  59         gids_saved = SMB_MALLOC_ARRAY(gid_t, ngrp_saved+1);
  60         if (!gids_saved) {
  61                 errno = ENOMEM;
  62                 return -1;
  63         }
  64
  65         ngrp_saved = getgroups(ngrp_saved, gids_saved);
  66         if (ngrp_saved == -1) {
  67                 SAFE_FREE(gids_saved);
  68                 /* very strange! */
  69                 return -1;
  70         }
  71
  72         if (initgroups(user, gid) != 0) {
  73                 DEBUG(0, ("getgrouplist_internals: initgroups() failed!\n"));
  74                 SAFE_FREE(gids_saved);
  75                 return -1;
  76         }
  77
  78         /* this must be done to cope with systems that put the current egid in the
  79            return from getgroups() */
  80         save_re_gid();
  81         set_effective_gid(gid);
  82         setgid(gid);
  83
  84         num_gids = getgroups(0, NULL);
  85         if (num_gids == -1) {
  86                 SAFE_FREE(gids_saved);
  87                 /* very strange! */
  88                 return -1;
  89         }
  90
  91         if (num_gids + 1 > *grpcnt) {
  92                 *grpcnt = num_gids + 1;
  93                 ret = -1;
  94         } else {
  95                 ret = getgroups(*grpcnt - 1, &groups[1]);
  96                 if (ret < 0) {
  97                         SAFE_FREE(gids_saved);
  98                         /* very strange! */
  99                         return -1;
 100                 }
 101                 groups[0] = gid;
 102                 *grpcnt = ret + 1;
 103         }
 104
 105         restore_re_gid();
 106
 107         if (sys_setgroups(ngrp_saved, gids_saved) != 0) {
 108                 /* yikes! */
 109                 DEBUG(0,("ERROR: getgrouplist: failed to reset group list!\n"));
 110                 smb_panic("getgrouplist: failed to reset group list!\n");
 111                 free(gids_saved);
 112                 return -1;
 113         }
 114
 115         free(gids_saved);
 116         return ret;
 117 }
 118 #endif
 119
 120 static int sys_getgrouplist(const char *user, gid_t gid, gid_t *groups, int *grpcnt)
 121 {
 122         int retval;
 123         BOOL winbind_env;
 124
 125         DEBUG(10,("sys_getgrouplist: user [%s]\n", user));
 126
 127         /* This is only ever called for Unix users, remote memberships are
 128          * always determined by the info3 coming back from auth3 or the
 129          * PAC. */
 130         winbind_env = winbind_env_set();
 131         winbind_off();
 132
 133 #ifdef HAVE_GETGROUPLIST
 134         retval = getgrouplist(user, gid, groups, grpcnt);
 135 #else
 136         become_root();
 137         retval = getgrouplist_internals(user, gid, groups, grpcnt);
 138         unbecome_root();
 139 #endif
 140
 141         /* allow winbindd lookups, but only if they were not already disabled */
 142         if (!winbind_env) {
 143                 winbind_on();
 144         }
 145
 146         return retval;
 147 }
 148
 149 BOOL getgroups_unix_user(TALLOC_CTX *mem_ctx, const char *user,
 150                          gid_t primary_gid,
 151                          gid_t **ret_groups, size_t *p_ngroups)
 152 {
 153         size_t ngrp;
 154         int max_grp;
 155         gid_t *temp_groups;
 156         gid_t *groups;
 157         int i;
 158
 159         max_grp = groups_max();
 160         temp_groups = SMB_MALLOC_ARRAY(gid_t, max_grp);
 161         if (! temp_groups) {
 162                 return False;
 163         }
 164
 165         if (sys_getgrouplist(user, primary_gid, temp_groups, &max_grp) == -1) {
 166                 temp_groups = SMB_REALLOC_ARRAY(temp_groups, gid_t, max_grp);
 167                 if (!temp_groups) {
 168                         return False;
 169                 }
 170
 171                 if (sys_getgrouplist(user, primary_gid,
 172                                      temp_groups, &max_grp) == -1) {
 173                         DEBUG(0, ("get_user_groups: failed to get the unix "
 174                                   "group list\n"));
 175                         SAFE_FREE(temp_groups);
 176                         return False;
 177                 }
 178         }
 179
 180         ngrp = 0;
 181         groups = NULL;
 182
 183         /* Add in primary group first */
 184         if (!add_gid_to_array_unique(mem_ctx, primary_gid, &groups, &ngrp)) {
 185                 SAFE_FREE(temp_groups);
 186                 return False;
 187         }
 188
 189         for (i=0; i<max_grp; i++) {
 190                 if (!add_gid_to_array_unique(mem_ctx, temp_groups[i],
 191                                         &groups, &ngrp)) {
 192                         SAFE_FREE(temp_groups);
 193                         return False;
 194                 }
 195         }
 196
 197         *p_ngroups = ngrp;
 198         *ret_groups = groups;
 199         SAFE_FREE(temp_groups);
 200         return True;
 201 }