source4/libcli/auth/gensec_gssapi.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    Kerberos backend for GENSEC
   5
   6    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program; if not, write to the Free Software
  21    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 */
  23
  24 #include "includes.h"
  25 #include "system/kerberos.h"
  26 #include "system/time.h"
  27 #include "libcli/auth/kerberos.h"
  28 #include "auth/auth.h"
  29
  30 #undef DBGC_CLASS
  31 #define DBGC_CLASS DBGC_AUTH
  32
  33 struct gensec_gssapi_state {
  34         gss_ctx_id_t gssapi_context;
  35         struct gss_channel_bindings_struct *input_chan_bindings;
  36         gss_name_t server_name;
  37         gss_name_t client_name;
  38         int want_flags, got_flags;
  39         const gss_OID_desc *gss_oid;
  40 };
  41 static int gensec_gssapi_destory(void *ptr)
  42 {
  43         struct gensec_gssapi_state *gensec_gssapi_state = ptr;
  44         OM_uint32 maj_stat, min_stat;
  45
  46         if (gensec_gssapi_state->gssapi_context != GSS_C_NO_CONTEXT) {
  47                 maj_stat = gss_delete_sec_context (&min_stat,
  48                                                    &gensec_gssapi_state->gssapi_context,
  49                                                    GSS_C_NO_BUFFER);
  50         }
  51
  52         if (gensec_gssapi_state->server_name != GSS_C_NO_NAME) {
  53                 maj_stat = gss_release_name(&min_stat, &gensec_gssapi_state->server_name);
  54         }
  55         if (gensec_gssapi_state->client_name != GSS_C_NO_NAME) {
  56                 maj_stat = gss_release_name(&min_stat, &gensec_gssapi_state->client_name);
  57         }
  58         return 0;
  59 }
  60
  61 static NTSTATUS gensec_gssapi_start(struct gensec_security *gensec_security)
  62 {
  63         struct gensec_gssapi_state *gensec_gssapi_state;
  64
  65         gensec_gssapi_state = talloc_p(gensec_security, struct gensec_gssapi_state);
  66         if (!gensec_gssapi_state) {
  67                 return NT_STATUS_NO_MEMORY;
  68         }
  69
  70         gensec_security->private_data = gensec_gssapi_state;
  71
  72         gensec_gssapi_state->gssapi_context = GSS_C_NO_CONTEXT;
  73         gensec_gssapi_state->server_name = GSS_C_NO_NAME;
  74         gensec_gssapi_state->client_name = GSS_C_NO_NAME;
  75
  76         talloc_set_destructor(gensec_gssapi_state, gensec_gssapi_destory);
  77
  78         /* TODO: Fill in channel bindings */
  79         gensec_gssapi_state->input_chan_bindings = GSS_C_NO_CHANNEL_BINDINGS;
  80
  81         gensec_gssapi_state->want_flags = 0;
  82         gensec_gssapi_state->got_flags = 0;
  83
  84         if (gensec_security->want_features & GENSEC_FEATURE_SESSION_KEY) {
  85                 /* GSSAPI won't give us the session keys */
  86                 return NT_STATUS_INVALID_PARAMETER;
  87         }
  88         if (gensec_security->want_features & GENSEC_FEATURE_SIGN) {
  89                 gensec_gssapi_state->want_flags |= GSS_C_INTEG_FLAG;
  90         }
  91         if (gensec_security->want_features & GENSEC_FEATURE_SEAL) {
  92                 gensec_gssapi_state->want_flags |= GSS_C_CONF_FLAG;
  93         }
  94
  95         if (strcmp(gensec_security->ops->oid, GENSEC_OID_KERBEROS5) == 0) {
  96                 static const gss_OID_desc gensec_gss_krb5_mechanism_oid_desc =
  97                         {9, (void *)discard_const_p(char, "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02")};
  98
  99                 gensec_gssapi_state->gss_oid = &gensec_gss_krb5_mechanism_oid_desc;
 100         } else if (strcmp(gensec_security->ops->oid, GENSEC_OID_SPNEGO) == 0) {
 101                 static const gss_OID_desc gensec_gss_spnego_mechanism_oid_desc =
 102                         {6, (void *)discard_const_p(char, "\x2b\x06\x01\x05\x05\x02")};
 103                 gensec_gssapi_state->gss_oid = &gensec_gss_spnego_mechanism_oid_desc;
 104         } else {
 105                 return NT_STATUS_INVALID_PARAMETER;
 106         }
 107
 108         return NT_STATUS_OK;
 109 }
 110
 111 static NTSTATUS gensec_gssapi_server_start(struct gensec_security *gensec_security)
 112 {
 113         NTSTATUS nt_status;
 114         struct gensec_gssapi_state *gensec_gssapi_state;
 115
 116         nt_status = gensec_gssapi_start(gensec_security);
 117         if (!NT_STATUS_IS_OK(nt_status)) {
 118                 return nt_status;
 119         }
 120
 121         gensec_gssapi_state = gensec_security->private_data;
 122
 123         return NT_STATUS_OK;
 124 }
 125
 126 static NTSTATUS gensec_gssapi_client_start(struct gensec_security *gensec_security)
 127 {
 128         struct gensec_gssapi_state *gensec_gssapi_state;
 129         NTSTATUS nt_status;
 130         gss_buffer_desc name_token;
 131         OM_uint32 maj_stat, min_stat;
 132
 133         nt_status = gensec_gssapi_start(gensec_security);
 134         if (!NT_STATUS_IS_OK(nt_status)) {
 135                 return nt_status;
 136         }
 137
 138         gensec_gssapi_state = gensec_security->private_data;
 139
 140         name_token.value = talloc_asprintf(gensec_gssapi_state, "%s@%s", gensec_get_target_service(gensec_security),
 141                                            gensec_get_target_hostname(gensec_security));
 142         DEBUG(0, ("name: %s\n", (char *)name_token.value));
 143         name_token.length = strlen(name_token.value);
 144
 145         maj_stat = gss_import_name (&min_stat,
 146                                     &name_token,
 147                                     GSS_C_NT_HOSTBASED_SERVICE,
 148                                     &gensec_gssapi_state->server_name);
 149
 150
 151         if (maj_stat) {
 152                 return NT_STATUS_UNSUCCESSFUL;
 153         }
 154         return NT_STATUS_OK;
 155 }
 156
 157
 158
 159 /**
 160  * Next state function for the GSSAPI GENSEC mechanism
 161  *
 162  * @param gensec_gssapi_state GSSAPI State
 163  * @param out_mem_ctx The TALLOC_CTX for *out to be allocated on
 164  * @param in The request, as a DATA_BLOB
 165  * @param out The reply, as an talloc()ed DATA_BLOB, on *out_mem_ctx
 166  * @return Error, MORE_PROCESSING_REQUIRED if a reply is sent,
 167  *                or NT_STATUS_OK if the user is authenticated.
 168  */
 169
 170 static NTSTATUS gensec_gssapi_update(struct gensec_security *gensec_security,
 171                                    TALLOC_CTX *out_mem_ctx,
 172                                    const DATA_BLOB in, DATA_BLOB *out)
 173 {
 174         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 175         NTSTATUS nt_status = NT_STATUS_UNSUCCESSFUL;
 176         OM_uint32 maj_stat, min_stat;
 177         OM_uint32 min_stat2;
 178         gss_buffer_desc input_token, output_token;
 179         gss_OID gss_oid_p;
 180         input_token.length = in.length;
 181         input_token.value = in.data;
 182
 183         switch (gensec_security->gensec_role) {
 184         case GENSEC_CLIENT:
 185         {
 186                 maj_stat = gss_init_sec_context(&min_stat,
 187                                                 GSS_C_NO_CREDENTIAL,
 188                                                 &gensec_gssapi_state->gssapi_context,
 189                                                 gensec_gssapi_state->server_name,
 190                                                 discard_const_p(gss_OID_desc, gensec_gssapi_state->gss_oid),
 191                                                 gensec_gssapi_state->want_flags,
 192                                                 0,
 193                                                 gensec_gssapi_state->input_chan_bindings,
 194                                                 &input_token,
 195                                                 NULL,
 196                                                 &output_token,
 197                                                 &gensec_gssapi_state->got_flags, /* ret flags */
 198                                                 NULL);
 199                 break;
 200         }
 201         case GENSEC_SERVER:
 202         {
 203                 maj_stat = gss_accept_sec_context(&min_stat,
 204                                                   gensec_gssapi_state->gssapi_context,
 205                                                   GSS_C_NO_CREDENTIAL,
 206                                                   &input_token,
 207                                                   gensec_gssapi_state->input_chan_bindings,
 208                                                   &gensec_gssapi_state->client_name,
 209                                                   &gss_oid_p,
 210                                                   &output_token,
 211                                                   &gensec_gssapi_state->got_flags,
 212                                                   NULL,
 213                                                   NULL);
 214                 gensec_gssapi_state->gss_oid = gss_oid_p;
 215                 break;
 216         }
 217         default:
 218                 return NT_STATUS_INVALID_PARAMETER;
 219
 220         }
 221
 222         *out = data_blob_talloc(out_mem_ctx, output_token.value, output_token.length);
 223         gss_release_buffer(&min_stat2, &output_token);
 224
 225         if (maj_stat == GSS_S_COMPLETE) {
 226                 return NT_STATUS_OK;
 227         } else if (maj_stat == GSS_S_CONTINUE_NEEDED) {
 228                 return NT_STATUS_MORE_PROCESSING_REQUIRED;
 229         } else {
 230                 gss_buffer_desc msg1, msg2;
 231                 OM_uint32 msg_ctx = 0;
 232
 233                 msg1.value = NULL;
 234                 msg2.value = NULL;
 235                 gss_display_status(&min_stat2, maj_stat, GSS_C_GSS_CODE,
 236                                    GSS_C_NULL_OID, &msg_ctx, &msg1);
 237                 gss_display_status(&min_stat2, min_stat, GSS_C_MECH_CODE,
 238                                    GSS_C_NULL_OID, &msg_ctx, &msg2);
 239                 DEBUG(1, ("gensec_gssapi_update: %s : %s\n", (char *)msg1.value, (char *)msg2.value));
 240                 gss_release_buffer(&min_stat2, &msg1);
 241                 gss_release_buffer(&min_stat2, &msg2);
 242
 243                 return nt_status;
 244         }
 245
 246 }
 247
 248 static NTSTATUS gensec_gssapi_wrap(struct gensec_security *gensec_security,
 249                                    TALLOC_CTX *mem_ctx,
 250                                    const DATA_BLOB *in,
 251                                    DATA_BLOB *out)
 252 {
 253         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 254         OM_uint32 maj_stat, min_stat;
 255         gss_buffer_desc input_token, output_token;
 256         int conf_state;
 257         input_token.length = in->length;
 258         input_token.value = in->data;
 259
 260         maj_stat = gss_wrap(&min_stat,
 261                             gensec_gssapi_state->gssapi_context,
 262                             gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL),
 263                             GSS_C_QOP_DEFAULT,
 264                             &input_token,
 265                             &conf_state,
 266                             &output_token);
 267         if (GSS_ERROR(maj_stat)) {
 268                 return NT_STATUS_ACCESS_DENIED;
 269         }
 270         *out = data_blob_talloc(mem_ctx, output_token.value, output_token.length);
 271
 272         gss_release_buffer(&min_stat, &output_token);
 273
 274         if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)
 275             && !conf_state) {
 276                 return NT_STATUS_ACCESS_DENIED;
 277         }
 278         return NT_STATUS_OK;
 279 }
 280
 281 static NTSTATUS gensec_gssapi_unwrap(struct gensec_security *gensec_security,
 282                                      TALLOC_CTX *mem_ctx,
 283                                      const DATA_BLOB *in,
 284                                      DATA_BLOB *out)
 285 {
 286         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 287         OM_uint32 maj_stat, min_stat;
 288         gss_buffer_desc input_token, output_token;
 289         int conf_state;
 290         gss_qop_t qop_state;
 291         input_token.length = in->length;
 292         input_token.value = in->data;
 293
 294         maj_stat = gss_unwrap(&min_stat,
 295                               gensec_gssapi_state->gssapi_context,
 296                               &input_token,
 297                               &output_token,
 298                               &conf_state,
 299                               &qop_state);
 300         if (GSS_ERROR(maj_stat)) {
 301                 return NT_STATUS_ACCESS_DENIED;
 302         }
 303         *out = data_blob_talloc(mem_ctx, output_token.value, output_token.length);
 304
 305         gss_release_buffer(&min_stat, &output_token);
 306
 307         if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)
 308             && !conf_state) {
 309                 return NT_STATUS_ACCESS_DENIED;
 310         }
 311         return NT_STATUS_OK;
 312 }
 313
 314 static BOOL gensec_gssapi_have_feature(struct gensec_security *gensec_security,
 315                                        uint32 feature)
 316 {
 317         struct gensec_gssapi_state *gensec_gssapi_state = gensec_security->private_data;
 318         if (feature & GENSEC_FEATURE_SIGN) {
 319                 return gensec_gssapi_state->got_flags & GSS_C_INTEG_FLAG;
 320         }
 321         if (feature & GENSEC_FEATURE_SEAL) {
 322                 return gensec_gssapi_state->got_flags & GSS_C_CONF_FLAG;
 323         }
 324         return False;
 325 }
 326
 327 /* As a server, this could in theory accept any GSSAPI mech */
 328 static const struct gensec_security_ops gensec_gssapi_krb5_security_ops = {
 329         .name           = "gssapi_krb5",
 330         .sasl_name      = "GSSAPI",
 331         .oid            = GENSEC_OID_KERBEROS5,
 332         .client_start   = gensec_gssapi_client_start,
 333         .server_start   = gensec_gssapi_server_start,
 334         .update         = gensec_gssapi_update,
 335         .wrap           = gensec_gssapi_wrap,
 336         .unwrap         = gensec_gssapi_unwrap,
 337         .have_feature   = gensec_gssapi_have_feature,
 338         .disabled_by_default = True
 339
 340 };
 341
 342 static const struct gensec_security_ops gensec_gssapi_spnego_security_ops = {
 343         .name           = "gssapi_spnego",
 344         .sasl_name      = "GSS-SPNEGO",
 345         .oid            = GENSEC_OID_SPNEGO,
 346         .client_start   = gensec_gssapi_client_start,
 347         .server_start   = gensec_gssapi_server_start,
 348         .update         = gensec_gssapi_update,
 349         .wrap           = gensec_gssapi_wrap,
 350         .unwrap         = gensec_gssapi_unwrap,
 351         .have_feature   = gensec_gssapi_have_feature,
 352         .disabled_by_default = True
 353
 354 };
 355
 356 NTSTATUS gensec_gssapi_init(void)
 357 {
 358         NTSTATUS ret;
 359
 360         ret = gensec_register(&gensec_gssapi_krb5_security_ops);
 361         if (!NT_STATUS_IS_OK(ret)) {
 362                 DEBUG(0,("Failed to register '%s' gensec backend!\n",
 363                         gensec_gssapi_krb5_security_ops.name));
 364                 return ret;
 365         }
 366
 367         ret = gensec_register(&gensec_gssapi_spnego_security_ops);
 368         if (!NT_STATUS_IS_OK(ret)) {
 369                 DEBUG(0,("Failed to register '%s' gensec backend!\n",
 370                         gensec_gssapi_spnego_security_ops.name));
 371                 return ret;
 372         }
 373
 374         return ret;
 375 }