source3/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 3 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, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 /*
  22    This file may assume linkage with smbd - for things like become_root()
  23    etc.
  24 */
  25
  26 #include "includes.h"
  27 #include "system/passwd.h"
  28 #include "nsswitch/winbind_client.h"
  29
  30 #ifndef HAVE_GETGROUPLIST
  31
  32 #ifdef HAVE_GETGRSET
  33 static int getgrouplist_getgrset(const char *user, gid_t gid, gid_t *groups,
  34                                  int *grpcnt)
  35 {
  36         char *grplist;
  37         char *grp;
  38         gid_t temp_gid;
  39         int num_gids = 1;
  40         int ret = 0;
  41         long l;
  42
  43         grplist = getgrset(user);
  44
  45         DEBUG(10, ("getgrset returned %s\n", grplist));
  46
  47         if (grplist == NULL) {
  48                 return -1;
  49         }
  50
  51         if (*grpcnt > 0) {
  52                 groups[0] = gid;
  53         }
  54
  55         while ((grp = strsep(&grplist, ",")) != NULL) {
  56                 l = strtol(grp, NULL, 10);
  57                 temp_gid = (gid_t) l;
  58                 if (temp_gid == gid) {
  59                         continue;
  60                 }
  61
  62                 if (num_gids + 1 > *grpcnt) {
  63                         num_gids++;
  64                         continue;
  65                 }
  66                 groups[num_gids++] = temp_gid;
  67         }
  68         free(grplist);
  69
  70         if (num_gids > *grpcnt) {
  71                 ret = -1;
  72         }
  73         *grpcnt = num_gids;
  74
  75         DEBUG(10, ("Found %d groups for user %s\n", *grpcnt, user));
  76
  77         return ret;
  78 }
  79
  80 #else /* HAVE_GETGRSET */
  81
  82 /*
  83   This is a *much* faster way of getting the list of groups for a user
  84   without changing the current supplementary group list. The old
  85   method used getgrent() which could take 20 minutes on a really big
  86   network with hundeds of thousands of groups and users. The new method
  87   takes a couple of seconds.
  88
  89   NOTE!! this function only works if it is called as root!
  90   */
  91
  92 static int getgrouplist_internals(const char *user, gid_t gid, gid_t *groups,
  93                                   int *grpcnt)
  94 {
  95         gid_t *gids_saved;
  96         int ret, ngrp_saved, num_gids;
  97
  98         if (non_root_mode()) {
  99                 *grpcnt = 0;
 100                 return 0;
 101         }
 102
 103         /* work out how many groups we need to save */
 104         ngrp_saved = getgroups(0, NULL);
 105         if (ngrp_saved == -1) {
 106                 /* this shouldn't happen */
 107                 return -1;
 108         }
 109
 110         gids_saved = SMB_MALLOC_ARRAY(gid_t, ngrp_saved+1);
 111         if (!gids_saved) {
 112                 errno = ENOMEM;
 113                 return -1;
 114         }
 115
 116         ngrp_saved = getgroups(ngrp_saved, gids_saved);
 117         if (ngrp_saved == -1) {
 118                 SAFE_FREE(gids_saved);
 119                 /* very strange! */
 120                 return -1;
 121         }
 122
 123         if (initgroups(user, gid) == -1) {
 124                 DEBUG(0, ("getgrouplist_internals: initgroups() failed!\n"));
 125                 SAFE_FREE(gids_saved);
 126                 return -1;
 127         }
 128
 129         /* this must be done to cope with systems that put the current egid in the
 130            return from getgroups() */
 131         save_re_gid();
 132         set_effective_gid(gid);
 133         setgid(gid);
 134
 135         num_gids = getgroups(0, NULL);
 136         if (num_gids == -1) {
 137                 SAFE_FREE(gids_saved);
 138                 /* very strange! */
 139                 return -1;
 140         }
 141
 142         if (num_gids + 1 > *grpcnt) {
 143                 *grpcnt = num_gids + 1;
 144                 ret = -1;
 145         } else {
 146                 ret = getgroups(*grpcnt - 1, &groups[1]);
 147                 if (ret < 0) {
 148                         SAFE_FREE(gids_saved);
 149                         /* very strange! */
 150                         return -1;
 151                 }
 152                 groups[0] = gid;
 153                 *grpcnt = ret + 1;
 154         }
 155
 156         restore_re_gid();
 157
 158         if (sys_setgroups(gid, ngrp_saved, gids_saved) != 0) {
 159                 /* yikes! */
 160                 DEBUG(0,("ERROR: getgrouplist: failed to reset group list!\n"));
 161                 smb_panic("getgrouplist: failed to reset group list!");
 162         }
 163
 164         free(gids_saved);
 165         return ret;
 166 }
 167 #endif /* HAVE_GETGRSET */
 168 #endif /* HAVE_GETGROUPLIST */
 169
 170 static int sys_getgrouplist(const char *user, gid_t gid, gid_t *groups, int *grpcnt)
 171 {
 172         int retval;
 173         bool winbind_env;
 174
 175         DEBUG(10,("sys_getgrouplist: user [%s]\n", user));
 176
 177         /* This is only ever called for Unix users, remote memberships are
 178          * always determined by the info3 coming back from auth3 or the
 179          * PAC. */
 180         winbind_env = winbind_env_set();
 181         (void)winbind_off();
 182
 183 #ifdef HAVE_GETGROUPLIST
 184         retval = getgrouplist(user, gid, groups, grpcnt);
 185 #else
 186 #ifdef HAVE_GETGRSET
 187         retval = getgrouplist_getgrset(user, gid, groups, grpcnt);
 188 #else
 189         become_root();
 190         retval = getgrouplist_internals(user, gid, groups, grpcnt);
 191         unbecome_root();
 192 #endif /* HAVE_GETGRSET */
 193 #endif /* HAVE_GETGROUPLIST */
 194
 195         /* allow winbindd lookups, but only if they were not already disabled */
 196         if (!winbind_env) {
 197                 (void)winbind_on();
 198         }
 199
 200         return retval;
 201 }
 202
 203 bool getgroups_unix_user(TALLOC_CTX *mem_ctx, const char *user,
 204                          gid_t primary_gid,
 205                          gid_t **ret_groups, uint32_t *p_ngroups)
 206 {
 207         uint32_t ngrp;
 208         int max_grp;
 209         gid_t *temp_groups;
 210         gid_t *groups;
 211         int i;
 212
 213         max_grp = MIN(128, groups_max());
 214         temp_groups = SMB_MALLOC_ARRAY(gid_t, max_grp);
 215         if (! temp_groups) {
 216                 return False;
 217         }
 218
 219         if (sys_getgrouplist(user, primary_gid, temp_groups, &max_grp) == -1) {
 220                 temp_groups = SMB_REALLOC_ARRAY(temp_groups, gid_t, max_grp);
 221                 if (!temp_groups) {
 222                         return False;
 223                 }
 224
 225                 if (sys_getgrouplist(user, primary_gid,
 226                                      temp_groups, &max_grp) == -1) {
 227                         DEBUG(0, ("get_user_groups: failed to get the unix "
 228                                   "group list\n"));
 229                         SAFE_FREE(temp_groups);
 230                         return False;
 231                 }
 232         }
 233
 234         ngrp = 0;
 235         groups = NULL;
 236
 237         /* Add in primary group first */
 238         if (!add_gid_to_array_unique(mem_ctx, primary_gid, &groups, &ngrp)) {
 239                 SAFE_FREE(temp_groups);
 240                 return False;
 241         }
 242
 243         for (i=0; i<max_grp; i++) {
 244                 if (!add_gid_to_array_unique(mem_ctx, temp_groups[i],
 245                                         &groups, &ngrp)) {
 246                         SAFE_FREE(temp_groups);
 247                         return False;
 248                 }
 249         }
 250
 251         *p_ngroups = ngrp;
 252         *ret_groups = groups;
 253         SAFE_FREE(temp_groups);
 254         return True;
 255 }