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 /* The Heimdal OID for getting the PAC */
  27 #define EXTRACT_PAC_AUTHZ_DATA_FROM_SEC_CONTEXT_OID_LENGTH 8
  28 /*                                                      EXTRACTION OID             AUTHZ ID */
  29 #define EXTRACT_PAC_AUTHZ_DATA_FROM_SEC_CONTEXT_OID "\x2a\x85\x70\x2b\x0d\x03" "\x81\x00"
  30
  31 static gss_OID_desc pac_data_oid = {
  32         EXTRACT_PAC_AUTHZ_DATA_FROM_SEC_CONTEXT_OID_LENGTH,
  33         (void *)EXTRACT_PAC_AUTHZ_DATA_FROM_SEC_CONTEXT_OID
  34 };
  35
  36 NTSTATUS gssapi_obtain_pac_blob(TALLOC_CTX *mem_ctx,
  37                                 gss_ctx_id_t gssapi_context,
  38                                 gss_name_t gss_client_name,
  39                                 DATA_BLOB *pac_blob)
  40 {
  41         OM_uint32 gss_maj, gss_min;
  42         gss_buffer_set_t set = GSS_C_NO_BUFFER_SET;
  43         gss_buffer_desc pac_buffer;
  44         gss_buffer_desc pac_display_buffer;
  45         gss_buffer_desc pac_name = {
  46                 .value = "urn:mspac:",
  47                 .length = sizeof("urn:mspac:")-1
  48         };
  49         NTSTATUS status;
  50         int more = -1;
  51         int authenticated = false;
  52         int complete = false;
  53
  54 #ifdef HAVE_GSS_GET_NAME_ATTRIBUTE
  55         gss_maj = gss_get_name_attribute(
  56                 &gss_min, gss_client_name, &pac_name,
  57                 &authenticated, &complete,
  58                 &pac_buffer, &pac_display_buffer, &more);
  59
  60         if (gss_maj != 0) {
  61                 DEBUG(0, ("obtaining PAC via GSSAPI gss_get_name_attribute failed: %s\n",
  62                           gssapi_error_string(mem_ctx, gss_maj, gss_min, gss_mech_krb5)));
  63                 return NT_STATUS_ACCESS_DENIED;
  64         } else if (authenticated && complete) {
  65                 /* The PAC blob is returned directly */
  66                 *pac_blob = data_blob_talloc(mem_ctx, pac_buffer.value,
  67                                             pac_buffer.length);
  68
  69                 if (!pac_blob->data) {
  70                         status = NT_STATUS_NO_MEMORY;
  71                 } else {
  72                         status = NT_STATUS_OK;
  73                 }
  74
  75                 gss_maj = gss_release_buffer(&gss_min, &pac_buffer);
  76                 gss_maj = gss_release_buffer(&gss_min, &pac_display_buffer);
  77                 return status;
  78         } else {
  79                 DEBUG(0, ("obtaining PAC via GSSAPI failed: authenticated: %s, complete: %s, more: %s\n",
  80                           authenticated ? "true" : "false",
  81                           complete ? "true" : "false",
  82                           more ? "true" : "false"));
  83                 return NT_STATUS_ACCESS_DENIED;
  84         }
  85
  86 #endif
  87         /* If we didn't have the routine to get a verified, validated
  88          * PAC (supplied only by MIT at the time of writing), then try
  89          * with the Heimdal OID (fetches the PAC directly and always
  90          * validates) */
  91         gss_maj = gss_inquire_sec_context_by_oid(
  92                                 &gss_min, gssapi_context,
  93                                 &pac_data_oid, &set);
  94
  95         /* First check for the error MIT gives for an unknown OID */
  96         if (gss_maj == GSS_S_UNAVAILABLE) {
  97                 DEBUG(1, ("unable to obtain a PAC against this GSSAPI library.  "
  98                           "GSSAPI secured connections are available only with Heimdal or MIT Kerberos >= 1.8\n"));
  99         } else if (gss_maj != 0) {
 100                 DEBUG(2, ("obtaining PAC via GSSAPI gss_inqiure_sec_context_by_oid (Heimdal OID) failed: %s\n",
 101                           gssapi_error_string(mem_ctx, gss_maj, gss_min, gss_mech_krb5)));
 102         } else {
 103                 if (set == GSS_C_NO_BUFFER_SET) {
 104                         DEBUG(0, ("gss_inquire_sec_context_by_oid returned unknown "
 105                                   "data in results.\n"));
 106                         return NT_STATUS_INTERNAL_ERROR;
 107                 }
 108
 109                 /* The PAC blob is returned directly */
 110                 *pac_blob = data_blob_talloc(mem_ctx, set->elements[0].value,
 111                                             set->elements[0].length);
 112                 if (!pac_blob->data) {
 113                         status = NT_STATUS_NO_MEMORY;
 114                 } else {
 115                         status = NT_STATUS_OK;
 116                 }
 117
 118                 gss_maj = gss_release_buffer_set(&gss_min, &set);
 119                 return status;
 120         }
 121         return NT_STATUS_ACCESS_DENIED;
 122 }
 123 #endif