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