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 #undef DBGC_CLASS
  37 #define DBGC_CLASS DBGC_RPC_SRV
  38
  39 /*******************************************************************
  40  Checks if access to an object should be granted, and returns that
  41  level of access for further checks.
  42
  43  If the user has either of needed_priv_1 or needed_priv_2 then they
  44  get the rights in rights_mask in addition to any calulated rights.
  45
  46  This handles the unusual case where we need to allow two different
  47  privileges to obtain exactly the same rights, which occours only in
  48  SAMR.
  49 ********************************************************************/
  50
  51 NTSTATUS access_check_object( struct security_descriptor *psd, struct security_token *token,
  52                               enum sec_privilege needed_priv_1, enum sec_privilege needed_priv_2,
  53                               uint32_t rights_mask,
  54                               uint32_t des_access, uint32_t *acc_granted,
  55                               const char *debug )
  56 {
  57         NTSTATUS status = NT_STATUS_ACCESS_DENIED;
  58         uint32_t saved_mask = 0;
  59         bool priv_granted = false;
  60         bool is_system = false;
  61         bool is_root = false;
  62
  63         /* Check if we are are the system token */
  64         if (security_token_is_system(token) &&
  65             security_token_system_privilege(token)) {
  66                 is_system = true;
  67         }
  68
  69         /* Check if we are root */
  70         if (root_mode()) {
  71                 is_root = true;
  72         }
  73
  74         /* Check if we are root */
  75
  76         /* check privileges; certain SAM access bits should be overridden
  77            by privileges (mostly having to do with creating/modifying/deleting
  78            users and groups) */
  79
  80         if ((needed_priv_1 != SEC_PRIV_INVALID && security_token_has_privilege(token, needed_priv_1)) ||
  81             (needed_priv_2 != SEC_PRIV_INVALID && security_token_has_privilege(token, needed_priv_2))) {
  82                 priv_granted = true;
  83                 saved_mask = (des_access & rights_mask);
  84                 des_access &= ~saved_mask;
  85
  86                 DEBUG(4,("access_check_object: user rights access mask [0x%x]\n",
  87                         rights_mask));
  88         }
  89
  90
  91         /* check the security descriptor first */
  92         status = se_access_check(psd, token, des_access, acc_granted);
  93         if (NT_STATUS_IS_OK(status)) {
  94                 goto done;
  95         }
  96
  97         if (is_system || is_root) {
  98                 DEBUG(4,("%s: ACCESS should be DENIED  (requested: %#010x)\n", debug, des_access));
  99                 DEBUGADD(4,("but overritten by %s\n",
 100                             is_root ? "euid == initial uid" : "system token"));
 101
 102                 priv_granted = true;
 103                 *acc_granted = des_access;
 104
 105                 status = NT_STATUS_OK;
 106                 goto done;
 107         }
 108
 109
 110 done:
 111         if (priv_granted) {
 112                 /* add in any bits saved during the privilege check (only
 113                    matters if status is ok) */
 114
 115                 *acc_granted |= rights_mask;
 116         }
 117
 118         DEBUG(4,("%s: access %s (requested: 0x%08x, granted: 0x%08x)\n",
 119                 debug, NT_STATUS_IS_OK(status) ? "GRANTED" : "DENIED",
 120                 des_access, *acc_granted));
 121
 122         return status;
 123 }
 124
 125
 126 /*******************************************************************
 127  Map any MAXIMUM_ALLOWED_ACCESS request to a valid access set.
 128 ********************************************************************/
 129
 130 void map_max_allowed_access(const struct security_token *nt_token,
 131                             const struct security_unix_token *unix_token,
 132                             uint32_t *pacc_requested)
 133 {
 134         if (!((*pacc_requested) & MAXIMUM_ALLOWED_ACCESS)) {
 135                 return;
 136         }
 137         *pacc_requested &= ~MAXIMUM_ALLOWED_ACCESS;
 138
 139         /* At least try for generic read|execute - Everyone gets that. */
 140         *pacc_requested |= GENERIC_READ_ACCESS|GENERIC_EXECUTE_ACCESS;
 141
 142         /* root gets anything. */
 143         if (unix_token->uid == sec_initial_uid()) {
 144                 *pacc_requested |= GENERIC_ALL_ACCESS;
 145                 return;
 146         }
 147
 148         /* Full Access for 'BUILTIN\Administrators' and 'BUILTIN\Account Operators */
 149
 150         if (security_token_has_sid(nt_token, &global_sid_Builtin_Administrators) ||
 151                         security_token_has_sid(nt_token, &global_sid_Builtin_Account_Operators)) {
 152                 *pacc_requested |= GENERIC_ALL_ACCESS;
 153                 return;
 154         }
 155
 156         /* Full access for DOMAIN\Domain Admins. */
 157         if ( IS_DC ) {
 158                 struct dom_sid domadmin_sid;
 159                 sid_compose(&domadmin_sid, get_global_sam_sid(),
 160                             DOMAIN_RID_ADMINS);
 161                 if (security_token_has_sid(nt_token, &domadmin_sid)) {
 162                         *pacc_requested |= GENERIC_ALL_ACCESS;
 163                         return;
 164                 }
 165         }
 166         /* TODO ! Check privileges. */
 167 }