auth/gensec/gensec_util.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    Generic Authentication Interface
   5
   6    Copyright (C) Andrew Tridgell 2003
   7    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2006
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include "includes.h"
  24 #include "auth/gensec/gensec.h"
  25 #include "auth/common_auth.h"
  26 #include "../lib/util/asn1.h"
  27
  28 NTSTATUS gensec_generate_session_info_pac(TALLOC_CTX *mem_ctx,
  29                                           struct gensec_security *gensec_security,
  30                                           struct smb_krb5_context *smb_krb5_context,
  31                                           DATA_BLOB *pac_blob,
  32                                           const char *principal_string,
  33                                           const struct tsocket_address *remote_address,
  34                                           struct auth_session_info **session_info)
  35 {
  36         uint32_t session_info_flags = 0;
  37
  38         if (gensec_security->want_features & GENSEC_FEATURE_UNIX_TOKEN) {
  39                 session_info_flags |= AUTH_SESSION_INFO_UNIX_TOKEN;
  40         }
  41
  42         session_info_flags |= AUTH_SESSION_INFO_DEFAULT_GROUPS;
  43
  44         if (!pac_blob) {
  45                 if (!gensec_setting_bool(gensec_security->settings, "gensec", "require_pac", false)) {
  46                         DEBUG(1, ("Unable to find PAC in ticket from %s, failing to allow access\n",
  47                                   principal_string));
  48                         return NT_STATUS_ACCESS_DENIED;
  49                 }
  50                 DEBUG(1, ("Unable to find PAC for %s, resorting to local user lookup\n",
  51                           principal_string));
  52         }
  53
  54         if (gensec_security->auth_context && gensec_security->auth_context->generate_session_info_pac) {
  55                 return gensec_security->auth_context->generate_session_info_pac(gensec_security->auth_context,
  56                                                                                 mem_ctx,
  57                                                                                 smb_krb5_context,
  58                                                                                 pac_blob,
  59                                                                                 principal_string,
  60                                                                                 remote_address,
  61                                                                                 session_info_flags,
  62                                                                                 session_info);
  63         } else {
  64                 DEBUG(0, ("Cannot generate a session_info without the auth_context\n"));
  65                 return NT_STATUS_INTERNAL_ERROR;
  66         }
  67 }
  68
  69 /*
  70  * These functions are for use in the deprecated
  71  * gensec_socket code (public because SPNEGO must
  72  * use them for recursion)
  73  */
  74 _PUBLIC_ NTSTATUS gensec_wrap_packets(struct gensec_security *gensec_security,
  75                              TALLOC_CTX *mem_ctx,
  76                              const DATA_BLOB *in,
  77                              DATA_BLOB *out,
  78                              size_t *len_processed)
  79 {
  80         if (!gensec_security->ops->wrap_packets) {
  81                 NTSTATUS nt_status;
  82                 size_t max_input_size;
  83                 DATA_BLOB unwrapped, wrapped;
  84                 max_input_size = gensec_max_input_size(gensec_security);
  85                 unwrapped = data_blob_const(in->data, MIN(max_input_size, (size_t)in->length));
  86
  87                 nt_status = gensec_wrap(gensec_security,
  88                                         mem_ctx,
  89                                         &unwrapped, &wrapped);
  90                 if (!NT_STATUS_IS_OK(nt_status)) {
  91                         return nt_status;
  92                 }
  93
  94                 *out = data_blob_talloc(mem_ctx, NULL, 4);
  95                 if (!out->data) {
  96                         return NT_STATUS_NO_MEMORY;
  97                 }
  98                 RSIVAL(out->data, 0, wrapped.length);
  99
 100                 if (!data_blob_append(mem_ctx, out, wrapped.data, wrapped.length)) {
 101                         return NT_STATUS_NO_MEMORY;
 102                 }
 103                 *len_processed = unwrapped.length;
 104                 return NT_STATUS_OK;
 105         }
 106         return gensec_security->ops->wrap_packets(gensec_security, mem_ctx, in, out,
 107                                                   len_processed);
 108 }
 109
 110 /*
 111  * These functions are for use in the deprecated
 112  * gensec_socket code (public because SPNEGO must
 113  * use them for recursion)
 114  */
 115 NTSTATUS gensec_unwrap_packets(struct gensec_security *gensec_security,
 116                                         TALLOC_CTX *mem_ctx,
 117                                         const DATA_BLOB *in,
 118                                         DATA_BLOB *out,
 119                                         size_t *len_processed)
 120 {
 121         if (!gensec_security->ops->unwrap_packets) {
 122                 DATA_BLOB wrapped;
 123                 NTSTATUS nt_status;
 124                 size_t packet_size;
 125                 if (in->length < 4) {
 126                         /* Missing the header we already had! */
 127                         DEBUG(0, ("Asked to unwrap packet of bogus length!  How did we get the short packet?!\n"));
 128                         return NT_STATUS_INVALID_PARAMETER;
 129                 }
 130
 131                 packet_size = RIVAL(in->data, 0);
 132
 133                 wrapped = data_blob_const(in->data + 4, packet_size);
 134
 135                 if (wrapped.length > (in->length - 4)) {
 136                         DEBUG(0, ("Asked to unwrap packed of bogus length %d > %d!  How did we get this?!\n",
 137                                   (int)wrapped.length, (int)(in->length - 4)));
 138                         return NT_STATUS_INTERNAL_ERROR;
 139                 }
 140
 141                 nt_status = gensec_unwrap(gensec_security,
 142                                           mem_ctx,
 143                                           &wrapped, out);
 144                 if (!NT_STATUS_IS_OK(nt_status)) {
 145                         return nt_status;
 146                 }
 147
 148                 *len_processed = packet_size + 4;
 149                 return nt_status;
 150         }
 151         return gensec_security->ops->unwrap_packets(gensec_security, mem_ctx, in, out,
 152                                                     len_processed);
 153 }
 154
 155 /*
 156  * These functions are for use in the deprecated
 157  * gensec_socket code (public because SPNEGO must
 158  * use them for recursion)
 159  */
 160 NTSTATUS gensec_packet_full_request(struct gensec_security *gensec_security,
 161                                     DATA_BLOB blob, size_t *size)
 162 {
 163         if (gensec_security->ops->packet_full_request) {
 164                 return gensec_security->ops->packet_full_request(gensec_security,
 165                                                                  blob, size);
 166         }
 167         if (gensec_security->ops->unwrap_packets) {
 168                 if (blob.length) {
 169                         *size = blob.length;
 170                         return NT_STATUS_OK;
 171                 }
 172                 return STATUS_MORE_ENTRIES;
 173         }
 174
 175         if (blob.length < 4) {
 176                 return STATUS_MORE_ENTRIES;
 177         }
 178         *size = 4 + RIVAL(blob.data, 0);
 179         if (*size > blob.length) {
 180                 return STATUS_MORE_ENTRIES;
 181         }
 182         return NT_STATUS_OK;
 183 }
 184
 185 /*
 186   magic check a GSS-API wrapper packet for an Kerberos OID
 187 */
 188 static bool gensec_gssapi_check_oid(const DATA_BLOB *blob, const char *oid)
 189 {
 190         bool ret;
 191         struct asn1_data *data = asn1_init(NULL);
 192
 193         if (!data) return false;
 194
 195         asn1_load(data, *blob);
 196         asn1_start_tag(data, ASN1_APPLICATION(0));
 197         asn1_check_OID(data, oid);
 198
 199         ret = !data->has_error;
 200
 201         asn1_free(data);
 202
 203         return ret;
 204 }
 205
 206 /**
 207  * Check if the packet is one for the KRB5 mechansim
 208  *
 209  * NOTE: This is a helper that can be employed by multiple mechanisms, do
 210  * not make assumptions about the private_data
 211  *
 212  * @param gensec_security GENSEC state, unused
 213  * @param in The request, as a DATA_BLOB
 214  * @return Error, INVALID_PARAMETER if it's not a packet for us
 215  *                or NT_STATUS_OK if the packet is ok.
 216  */
 217
 218 NTSTATUS gensec_magic_check_krb5_oid(struct gensec_security *unused,
 219                                         const DATA_BLOB *blob)
 220 {
 221         if (gensec_gssapi_check_oid(blob, GENSEC_OID_KERBEROS5)) {
 222                 return NT_STATUS_OK;
 223         } else {
 224                 return NT_STATUS_INVALID_PARAMETER;
 225         }
 226 }