source3/rpc_server/srv_access_check.c

   1 /*
   2  *  Unix SMB/CIFS implementation.
   3  *  RPC Pipe client / server routines
   4  *  Copyright (C) Andrew Tridgell                   1992-1997,
   5  *  Copyright (C) Luke Kenneth Casson Leighton      1996-1997,
   6  *  Copyright (C) Paul Ashton                       1997,
   7  *  Copyright (C) Marc Jacobsen                     1999,
   8  *  Copyright (C) Jeremy Allison                    2001-2008,
   9  *  Copyright (C) Jean François Micouleau           1998-2001,
  10  *  Copyright (C) Jim McDonough <jmcd@us.ibm.com>   2002,
  11  *  Copyright (C) Gerald (Jerry) Carter             2003-2004,
  12  *  Copyright (C) Simo Sorce                        2003.
  13  *  Copyright (C) Volker Lendecke                   2005.
  14  *  Copyright (C) Guenther Deschner                 2008.
  15  *
  16  *  This program is free software; you can redistribute it and/or modify
  17  *  it under the terms of the GNU General Public License as published by
  18  *  the Free Software Foundation; either version 3 of the License, or
  19  *  (at your option) any later version.
  20  *
  21  *  This program is distributed in the hope that it will be useful,
  22  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  23  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24  *  GNU General Public License for more details.
  25  *
  26  *  You should have received a copy of the GNU General Public License
  27  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  28  */
  29
  30 #include "includes.h"
  31 #include "system/passwd.h" /* uid_wrapper */
  32 #include "rpc_server/srv_access_check.h"
  33 #include "../libcli/security/security.h"
  34 #include "passdb/machine_sid.h"
  35
  36 /*******************************************************************
  37  Checks if access to an object should be granted, and returns that
  38  level of access for further checks.
  39
  40  If the user has either of needed_priv_1 or needed_priv_2 then they
  41  get the rights in rights_mask in addition to any calulated rights.
  42
  43  This handles the unusual case where we need to allow two different
  44  privileges to obtain exactly the same rights, which occours only in
  45  SAMR.
  46 ********************************************************************/
  47
  48 NTSTATUS access_check_object( struct security_descriptor *psd, struct security_token *token,
  49                               enum sec_privilege needed_priv_1, enum sec_privilege needed_priv_2,
  50                               uint32 rights_mask,
  51                               uint32 des_access, uint32 *acc_granted,
  52                               const char *debug )
  53 {
  54         NTSTATUS status = NT_STATUS_ACCESS_DENIED;
  55         uint32 saved_mask = 0;
  56         bool priv_granted = false;
  57         bool is_system = false;
  58         bool is_root = false;
  59
  60         /* Check if we are are the system token */
  61         if (security_token_is_system(token) &&
  62             security_token_system_privilege(token)) {
  63                 is_system = true;
  64         }
  65
  66         /* Check if we are root */
  67         if (geteuid() == sec_initial_uid()) {
  68                 is_root = true;
  69         }
  70
  71         /* Check if we are root */
  72
  73         /* check privileges; certain SAM access bits should be overridden
  74            by privileges (mostly having to do with creating/modifying/deleting
  75            users and groups) */
  76
  77         if ((needed_priv_1 != SEC_PRIV_INVALID && security_token_has_privilege(token, needed_priv_1)) ||
  78             (needed_priv_2 != SEC_PRIV_INVALID && security_token_has_privilege(token, needed_priv_2))) {
  79                 priv_granted = true;
  80                 saved_mask = (des_access & rights_mask);
  81                 des_access &= ~saved_mask;
  82
  83                 DEBUG(4,("access_check_object: user rights access mask [0x%x]\n",
  84                         rights_mask));
  85         }
  86
  87
  88         /* check the security descriptor first */
  89         status = se_access_check(psd, token, des_access, acc_granted);
  90         if (NT_STATUS_IS_OK(status)) {
  91                 goto done;
  92         }
  93
  94         if (is_system || is_root) {
  95                 DEBUG(4,("%s: ACCESS should be DENIED  (requested: %#010x)\n", debug, des_access));
  96                 DEBUGADD(4,("but overritten by %s\n",
  97                             is_root ? "euid == initial uid" : "system token"));
  98
  99                 priv_granted = true;
 100                 *acc_granted = des_access;
 101
 102                 status = NT_STATUS_OK;
 103                 goto done;
 104         }
 105
 106
 107 done:
 108         if (priv_granted) {
 109                 /* add in any bits saved during the privilege check (only
 110                    matters if status is ok) */
 111
 112                 *acc_granted |= rights_mask;
 113         }
 114
 115         DEBUG(4,("%s: access %s (requested: 0x%08x, granted: 0x%08x)\n",
 116                 debug, NT_STATUS_IS_OK(status) ? "GRANTED" : "DENIED",
 117                 des_access, *acc_granted));
 118
 119         return status;
 120 }
 121
 122
 123 /*******************************************************************
 124  Map any MAXIMUM_ALLOWED_ACCESS request to a valid access set.
 125 ********************************************************************/
 126
 127 void map_max_allowed_access(const struct security_token *nt_token,
 128                             const struct security_unix_token *unix_token,
 129                             uint32_t *pacc_requested)
 130 {
 131         if (!((*pacc_requested) & MAXIMUM_ALLOWED_ACCESS)) {
 132                 return;
 133         }
 134         *pacc_requested &= ~MAXIMUM_ALLOWED_ACCESS;
 135
 136         /* At least try for generic read|execute - Everyone gets that. */
 137         *pacc_requested = GENERIC_READ_ACCESS|GENERIC_EXECUTE_ACCESS;
 138
 139         /* root gets anything. */
 140         if (unix_token->uid == sec_initial_uid()) {
 141                 *pacc_requested |= GENERIC_ALL_ACCESS;
 142                 return;
 143         }
 144
 145         /* Full Access for 'BUILTIN\Administrators' and 'BUILTIN\Account Operators */
 146
 147         if (security_token_has_sid(nt_token, &global_sid_Builtin_Administrators) ||
 148                         security_token_has_sid(nt_token, &global_sid_Builtin_Account_Operators)) {
 149                 *pacc_requested |= GENERIC_ALL_ACCESS;
 150                 return;
 151         }
 152
 153         /* Full access for DOMAIN\Domain Admins. */
 154         if ( IS_DC ) {
 155                 struct dom_sid domadmin_sid;
 156                 sid_compose(&domadmin_sid, get_global_sam_sid(),
 157                             DOMAIN_RID_ADMINS);
 158                 if (security_token_has_sid(nt_token, &domadmin_sid)) {
 159                         *pacc_requested |= GENERIC_ALL_ACCESS;
 160                         return;
 161                 }
 162         }
 163         /* TODO ! Check privileges. */
 164 }