auth/kerberos/gssapi_pac.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    kerberos authorization data (PAC) utility library
   4    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2011
   5    Copyright (C) Simo Sorce 2010.
   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 #include "includes.h"
  22 #ifdef HAVE_KRB5
  23
  24 #include "libcli/auth/krb5_wrap.h"
  25
  26 #if 0
  27 /* FIXME - need proper configure/waf test
  28  * to determine if gss_mech_krb5 and friends
  29  * exist. JRA.
  30  */
  31 /*
  32  * These are not exported by Solaris -lkrb5
  33  * Maybe move to libreplace somewhere?
  34  */
  35 static const gss_OID_desc krb5_gss_oid_array[] = {
  36         /* this is the official, rfc-specified OID */
  37         { 9, "\052\206\110\206\367\022\001\002\002" },
  38         /* this is the pre-RFC mech OID */
  39         { 5, "\053\005\001\005\002" },
  40         /* this is the unofficial, incorrect mech OID emitted by MS */
  41         { 9, "\052\206\110\202\367\022\001\002\002" },
  42         { 0, 0 }
  43 };
  44
  45 const gss_OID_desc * const gss_mech_krb5              = krb5_gss_oid_array+0;
  46 const gss_OID_desc * const gss_mech_krb5_old          = krb5_gss_oid_array+1;
  47 const gss_OID_desc * const gss_mech_krb5_wrong        = krb5_gss_oid_array+2;
  48 #endif
  49
  50 /* The Heimdal OID for getting the PAC */
  51 #define EXTRACT_PAC_AUTHZ_DATA_FROM_SEC_CONTEXT_OID_LENGTH 8
  52 /*                                                      EXTRACTION OID             AUTHZ ID */
  53 #define EXTRACT_PAC_AUTHZ_DATA_FROM_SEC_CONTEXT_OID "\x2a\x85\x70\x2b\x0d\x03" "\x81\x00"
  54
  55 NTSTATUS gssapi_obtain_pac_blob(TALLOC_CTX *mem_ctx,
  56                                 gss_ctx_id_t gssapi_context,
  57                                 gss_name_t gss_client_name,
  58                                 DATA_BLOB *pac_blob)
  59 {
  60         NTSTATUS status;
  61         OM_uint32 gss_maj, gss_min;
  62 #ifdef HAVE_GSS_GET_NAME_ATTRIBUTE
  63         gss_buffer_desc pac_buffer;
  64         gss_buffer_desc pac_display_buffer;
  65         gss_buffer_desc pac_name = {
  66                 .value = discard_const("urn:mspac:"),
  67                 .length = sizeof("urn:mspac:")-1
  68         };
  69         int more = -1;
  70         int authenticated = false;
  71         int complete = false;
  72
  73         gss_maj = gss_get_name_attribute(
  74                 &gss_min, gss_client_name, &pac_name,
  75                 &authenticated, &complete,
  76                 &pac_buffer, &pac_display_buffer, &more);
  77
  78         if (gss_maj != 0) {
  79                 DEBUG(0, ("obtaining PAC via GSSAPI gss_get_name_attribute failed: %s\n",
  80                           gssapi_error_string(mem_ctx, gss_maj, gss_min, gss_mech_krb5)));
  81                 return NT_STATUS_ACCESS_DENIED;
  82         } else if (authenticated && complete) {
  83                 /* The PAC blob is returned directly */
  84                 *pac_blob = data_blob_talloc(mem_ctx, pac_buffer.value,
  85                                             pac_buffer.length);
  86
  87                 if (!pac_blob->data) {
  88                         status = NT_STATUS_NO_MEMORY;
  89                 } else {
  90                         status = NT_STATUS_OK;
  91                 }
  92
  93                 gss_maj = gss_release_buffer(&gss_min, &pac_buffer);
  94                 gss_maj = gss_release_buffer(&gss_min, &pac_display_buffer);
  95                 return status;
  96         } else {
  97                 DEBUG(0, ("obtaining PAC via GSSAPI failed: authenticated: %s, complete: %s, more: %s\n",
  98                           authenticated ? "true" : "false",
  99                           complete ? "true" : "false",
 100                           more ? "true" : "false"));
 101                 return NT_STATUS_ACCESS_DENIED;
 102         }
 103
 104 #elif defined(HAVE_GSS_INQUIRE_SEC_CONTEXT_BY_OID)
 105         gss_OID_desc pac_data_oid = {
 106                 .elements = discard_const(EXTRACT_PAC_AUTHZ_DATA_FROM_SEC_CONTEXT_OID),
 107                 .length = EXTRACT_PAC_AUTHZ_DATA_FROM_SEC_CONTEXT_OID_LENGTH
 108         };
 109
 110         gss_buffer_set_t set = GSS_C_NO_BUFFER_SET;
 111
 112         /* If we didn't have the routine to get a verified, validated
 113          * PAC (supplied only by MIT at the time of writing), then try
 114          * with the Heimdal OID (fetches the PAC directly and always
 115          * validates) */
 116         gss_maj = gss_inquire_sec_context_by_oid(
 117                                 &gss_min, gssapi_context,
 118                                 &pac_data_oid, &set);
 119
 120         /* First check for the error MIT gives for an unknown OID */
 121         if (gss_maj == GSS_S_UNAVAILABLE) {
 122                 DEBUG(1, ("unable to obtain a PAC against this GSSAPI library.  "
 123                           "GSSAPI secured connections are available only with Heimdal or MIT Kerberos >= 1.8\n"));
 124         } else if (gss_maj != 0) {
 125                 DEBUG(2, ("obtaining PAC via GSSAPI gss_inqiure_sec_context_by_oid (Heimdal OID) failed: %s\n",
 126                           gssapi_error_string(mem_ctx, gss_maj, gss_min, gss_mech_krb5)));
 127         } else {
 128                 if (set == GSS_C_NO_BUFFER_SET) {
 129                         DEBUG(0, ("gss_inquire_sec_context_by_oid returned unknown "
 130                                   "data in results.\n"));
 131                         return NT_STATUS_INTERNAL_ERROR;
 132                 }
 133
 134                 /* The PAC blob is returned directly */
 135                 *pac_blob = data_blob_talloc(mem_ctx, set->elements[0].value,
 136                                             set->elements[0].length);
 137                 if (!pac_blob->data) {
 138                         status = NT_STATUS_NO_MEMORY;
 139                 } else {
 140                         status = NT_STATUS_OK;
 141                 }
 142
 143                 gss_maj = gss_release_buffer_set(&gss_min, &set);
 144                 return status;
 145         }
 146 #else
 147         DEBUG(1, ("unable to obtain a PAC against this GSSAPI library.  "
 148                   "GSSAPI secured connections are available only with Heimdal or MIT Kerberos >= 1.8\n"));
 149 #endif
 150         return NT_STATUS_ACCESS_DENIED;
 151 }
 152 #endif