www.project-moonshot.org Git - mech_eap.orig/blob - util_sm.c

   1 /*
   2  * Copyright (c) 2011, JANET(UK)
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  *
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * 3. Neither the name of JANET(UK) nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  21  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 /*
  34  * Context establishment state machine.
  35  */
  36
  37 #include "gssapiP_eap.h"
  38
  39 /* private flags */
  40 #define SM_FLAG_TRANSITED                   0x80000000
  41
  42 #define SM_ASSERT_VALID(ctx, status)        do { \
  43         assert(GSS_ERROR((status)) || \
  44                ((status) == GSS_S_CONTINUE_NEEDED && ((ctx)->state > GSSEAP_STATE_INITIAL && (ctx)->state < GSSEAP_STATE_ESTABLISHED)) || \
  45                ((status) == GSS_S_COMPLETE && (ctx)->state == GSSEAP_STATE_ESTABLISHED)); \
  46     } while (0)
  47
  48 static const char *
  49 gssEapStateToString(enum gss_eap_state state)
  50 {
  51     const char *s;
  52
  53     switch (state) {
  54     case GSSEAP_STATE_INITIAL:
  55         s = "INITIAL";
  56         break;
  57     case GSSEAP_STATE_AUTHENTICATE:
  58         s = "AUTHENTICATE";
  59         break;
  60     case GSSEAP_STATE_INITIATOR_EXTS:
  61         s = "INITIATOR_EXTS";
  62         break;
  63     case GSSEAP_STATE_ACCEPTOR_EXTS:
  64         s = "ACCEPTOR_EXTS";
  65         break;
  66     case GSSEAP_STATE_REAUTHENTICATE:
  67         s = "REAUTHENTICATE";
  68         break;
  69     case GSSEAP_STATE_ESTABLISHED:
  70         s = "ESTABLISHED";
  71         break;
  72     default:
  73         s = "INVALID";
  74         break;
  75     }
  76
  77     return s;
  78 }
  79
  80 #ifdef GSSEAP_DEBUG
  81 void
  82 gssEapSmTransition(gss_ctx_id_t ctx, enum gss_eap_state state)
  83 {
  84     assert(state > ctx->state);
  85     assert(state <= GSSEAP_STATE_ESTABLISHED);
  86
  87     fprintf(stderr, "GSS-EAP: state transition %s->%s\n",
  88             gssEapStateToString(ctx->state), gssEapStateToString(state));
  89
  90     ctx->state = state;
  91 }
  92 #endif
  93
  94 static OM_uint32
  95 makeErrorToken(OM_uint32 *minor,
  96                OM_uint32 majorStatus,
  97                OM_uint32 minorStatus,
  98                gss_buffer_set_t *outputToken)
  99 {
 100     OM_uint32 major;
 101     unsigned char errorData[8];
 102     gss_buffer_desc errorBuffer;
 103
 104     assert(GSS_ERROR(majorStatus));
 105
 106     major = gss_create_empty_buffer_set(minor, outputToken);
 107     if (GSS_ERROR(major))
 108         return major;
 109
 110     /*
 111      * Only return error codes that the initiator could have caused,
 112      * to avoid information leakage.
 113      */
 114     if (IS_RADIUS_ERROR(minorStatus)) {
 115         /* Squash RADIUS error codes */
 116         minorStatus = GSSEAP_RADIUS_PROT_FAILURE;
 117     } else if (!IS_WIRE_ERROR(minorStatus)) {
 118         /* Don't return non-wire error codes */
 119         return GSS_S_COMPLETE;
 120     }
 121
 122     minorStatus -= ERROR_TABLE_BASE_eapg;
 123
 124     store_uint32_be(majorStatus, &errorData[0]);
 125     store_uint32_be(minorStatus, &errorData[4]);
 126
 127     errorBuffer.length = sizeof(errorData);
 128     errorBuffer.value = errorData;
 129
 130     major = gss_add_buffer_set_member(minor, &errorBuffer, outputToken);
 131     if (GSS_ERROR(major))
 132         return major;
 133
 134     return GSS_S_COMPLETE;
 135 }
 136
 137 static OM_uint32
 138 allocInnerTokens(OM_uint32 *minor,
 139                  size_t count,
 140                  gss_buffer_set_t *pTokens,
 141                  OM_uint32 **pTokenTypes)
 142 {
 143     OM_uint32 major, tmpMinor;
 144     gss_buffer_set_t tokens = GSS_C_NO_BUFFER_SET;
 145     OM_uint32 *tokenTypes = NULL;
 146
 147     major = gss_create_empty_buffer_set(minor, &tokens);
 148     if (GSS_ERROR(major))
 149         goto cleanup;
 150
 151     assert(tokens->count == 0);
 152     assert(tokens->elements == NULL);
 153
 154     tokens->elements = (gss_buffer_desc *)GSSEAP_CALLOC(count, sizeof(gss_buffer_desc));
 155     if (tokens->elements == NULL) {
 156         major = GSS_S_FAILURE;
 157         *minor = ENOMEM;
 158         goto cleanup;
 159     }
 160
 161     tokenTypes = (OM_uint32 *)GSSEAP_CALLOC(count, sizeof(OM_uint32));
 162     if (tokenTypes == NULL) {
 163         major = GSS_S_FAILURE;
 164         *minor = ENOMEM;
 165         goto cleanup;
 166     }
 167
 168     major = GSS_S_COMPLETE;
 169     *minor = 0;
 170
 171 cleanup:
 172     if (GSS_ERROR(major)) {
 173         gss_release_buffer_set(&tmpMinor, &tokens);
 174         tokens = GSS_C_NO_BUFFER_SET;
 175         if (tokenTypes != NULL) {
 176             GSSEAP_FREE(tokenTypes);
 177             tokenTypes = NULL;
 178         }
 179     }
 180
 181     *pTokens = tokens;
 182     *pTokenTypes = tokenTypes;
 183
 184     return major;
 185 }
 186
 187 OM_uint32
 188 gssEapSmStep(OM_uint32 *minor,
 189              gss_cred_id_t cred,
 190              gss_ctx_id_t ctx,
 191              gss_name_t target,
 192              gss_OID mech,
 193              OM_uint32 reqFlags,
 194              OM_uint32 timeReq,
 195              gss_channel_bindings_t chanBindings,
 196              gss_buffer_t inputToken,
 197              gss_buffer_t outputToken,
 198              struct gss_eap_sm *sm, /* ordered by state */
 199              size_t smCount)
 200 {
 201     OM_uint32 major, tmpMajor, tmpMinor;
 202     gss_buffer_desc unwrappedInputToken = GSS_C_EMPTY_BUFFER;
 203     gss_buffer_desc unwrappedOutputToken = GSS_C_EMPTY_BUFFER;
 204     gss_buffer_set_t innerInputTokens = GSS_C_NO_BUFFER_SET;
 205     gss_buffer_set_t innerOutputTokens = GSS_C_NO_BUFFER_SET;
 206     OM_uint32 *inputTokenTypes = NULL, *outputTokenTypes = NULL;
 207     unsigned int smFlags = 0;
 208     size_t i, j;
 209     int initialContextToken = 0;
 210
 211     assert(smCount > 0);
 212
 213     *minor = 0;
 214
 215     outputToken->length = 0;
 216     outputToken->value = NULL;
 217
 218     if (inputToken != GSS_C_NO_BUFFER && inputToken->length != 0) {
 219         enum gss_eap_token_type tokType;
 220
 221         major = gssEapVerifyToken(minor, ctx, inputToken, &tokType,
 222                                   &unwrappedInputToken);
 223         if (GSS_ERROR(major))
 224             goto cleanup;
 225
 226         if (tokType != TOK_TYPE_ESTABLISH_CONTEXT) {
 227             major = GSS_S_DEFECTIVE_TOKEN;
 228             *minor = GSSEAP_WRONG_TOK_ID;
 229             goto cleanup;
 230         }
 231     } else if (!CTX_IS_INITIATOR(ctx) || ctx->state != GSSEAP_STATE_INITIAL) {
 232         major = GSS_S_DEFECTIVE_TOKEN;
 233         *minor = GSSEAP_WRONG_SIZE;
 234         goto cleanup;
 235     } else {
 236         initialContextToken = 1;
 237     }
 238
 239     if (ctx->state == GSSEAP_STATE_ESTABLISHED) {
 240         major = GSS_S_BAD_STATUS;
 241         *minor = GSSEAP_CONTEXT_ESTABLISHED;
 242         goto cleanup;
 243     }
 244
 245     assert(ctx->state < GSSEAP_STATE_ESTABLISHED);
 246
 247     major = gssEapDecodeInnerTokens(minor, &unwrappedInputToken,
 248                                     &innerInputTokens, &inputTokenTypes);
 249     if (GSS_ERROR(major))
 250         goto cleanup;
 251
 252     assert(innerInputTokens != GSS_C_NO_BUFFER_SET);
 253
 254     major = allocInnerTokens(minor, smCount, &innerOutputTokens, &outputTokenTypes);
 255     if (GSS_ERROR(major))
 256         goto cleanup;
 257
 258     /* Process all the tokens that are valid for the current state. */
 259     for (i = 0; i < smCount; i++) {
 260         struct gss_eap_sm *smp = &sm[i];
 261         int processToken = 0;
 262         gss_buffer_t innerInputToken = GSS_C_NO_BUFFER;
 263         OM_uint32 *inputTokenType = NULL;
 264         gss_buffer_desc innerOutputToken = GSS_C_EMPTY_BUFFER;
 265
 266         if ((smp->validStates & ctx->state) == 0)
 267             continue;
 268
 269         if (smp->inputTokenType == ITOK_TYPE_NONE || initialContextToken) {
 270             processToken = 1;
 271         } else if ((smFlags & SM_FLAG_TRANSITED) == 0) {
 272             for (j = 0; j < innerInputTokens->count; j++) {
 273                 if ((inputTokenTypes[j] & ITOK_TYPE_MASK) == smp->inputTokenType) {
 274                     if (processToken) {
 275                         major = GSS_S_DEFECTIVE_TOKEN;
 276                         *minor = GSSEAP_DUPLICATE_ITOK;
 277                         break;
 278                     }
 279                     processToken = 1;
 280                     innerInputToken = &innerInputTokens->elements[j];
 281                     inputTokenType = &inputTokenTypes[j];
 282                 }
 283             }
 284             if (GSS_ERROR(major))
 285                 break;
 286         }
 287
 288         if (processToken) {
 289             enum gss_eap_state oldState = ctx->state;
 290
 291             smFlags = 0;
 292
 293             major = smp->processToken(minor, cred, ctx, target, mech, reqFlags,
 294                                       timeReq, chanBindings, innerInputToken,
 295                                       &innerOutputToken, &smFlags);
 296             if (GSS_ERROR(major))
 297                 break;
 298
 299             if (inputTokenType != NULL)
 300                 *inputTokenType |= ITOK_FLAG_VERIFIED;
 301             if (ctx->state != oldState)
 302                 smFlags |= SM_FLAG_TRANSITED;
 303
 304             if (innerOutputToken.value != NULL) {
 305                 innerOutputTokens->elements[innerOutputTokens->count] = innerOutputToken;
 306                 assert(smp->outputTokenType != ITOK_TYPE_NONE);
 307                 outputTokenTypes[innerOutputTokens->count] = smp->outputTokenType;
 308                 if (smp->itokFlags & SM_ITOK_FLAG_CRITICAL)
 309                     outputTokenTypes[innerOutputTokens->count] |= ITOK_FLAG_CRITICAL;
 310                 innerOutputTokens->count++;
 311             }
 312             /*
 313              * Break out if explicitly requested, or if we made a state transition
 314              * and have some tokens to send.
 315              */
 316             if ((smFlags & SM_FLAG_STOP_EVAL) ||
 317                 ((smFlags & SM_FLAG_TRANSITED) &&
 318                  ((smFlags & SM_FLAG_FORCE_SEND_TOKEN) || innerOutputTokens->count != 0))) {
 319                 SM_ASSERT_VALID(ctx, major);
 320                 break;
 321             }
 322         } else if ((smp->itokFlags & SM_ITOK_FLAG_REQUIRED) &&
 323             smp->inputTokenType != ITOK_TYPE_NONE) {
 324             major = GSS_S_DEFECTIVE_TOKEN;
 325             *minor = GSSEAP_MISSING_REQUIRED_ITOK;
 326             break;
 327         }
 328     }
 329
 330     assert(innerOutputTokens->count <= smCount);
 331
 332     /* Check we understood all critical tokens */
 333     if (!GSS_ERROR(major)) {
 334         for (j = 0; j < innerInputTokens->count; j++) {
 335             if ((inputTokenTypes[j] & ITOK_FLAG_CRITICAL) &&
 336                 (inputTokenTypes[j] & ITOK_FLAG_VERIFIED) == 0) {
 337                 major = GSS_S_UNAVAILABLE;
 338                 *minor = GSSEAP_CRIT_ITOK_UNAVAILABLE;
 339                 goto cleanup;
 340             }
 341         }
 342     }
 343
 344     /* Emit an error token if we are the acceptor */
 345     if (GSS_ERROR(major)) {
 346         if (CTX_IS_INITIATOR(ctx))
 347             goto cleanup; /* return error directly to caller */
 348
 349         /* replace any emitted tokens with error token */
 350         gss_release_buffer_set(&tmpMinor, &innerOutputTokens);
 351
 352         tmpMajor = makeErrorToken(&tmpMinor, major, *minor, &innerOutputTokens);
 353         if (GSS_ERROR(tmpMajor)) {
 354             major = tmpMajor;
 355             *minor = tmpMinor;
 356             goto cleanup;
 357         }
 358
 359         if (innerOutputTokens->count != 0)
 360             outputTokenTypes[0] = ITOK_TYPE_CONTEXT_ERR | ITOK_FLAG_CRITICAL;
 361     }
 362
 363     /* Format composite output token */
 364     if (innerOutputTokens->count != 0 ||            /* inner tokens to send */
 365         !CTX_IS_INITIATOR(ctx) ||                   /* any leg acceptor */
 366         ctx->state != GSSEAP_STATE_ESTABLISHED) {   /* non-last leg initiator */
 367         tmpMajor = gssEapEncodeInnerTokens(&tmpMinor, innerOutputTokens,
 368                                            outputTokenTypes, &unwrappedOutputToken);
 369         if (tmpMajor == GSS_S_COMPLETE) {
 370             tmpMajor = gssEapMakeToken(&tmpMinor, ctx, &unwrappedOutputToken,
 371                                        TOK_TYPE_ESTABLISH_CONTEXT, outputToken);
 372             if (GSS_ERROR(tmpMajor)) {
 373                 major = tmpMajor;
 374                 *minor = tmpMinor;
 375                 goto cleanup;
 376             }
 377         }
 378     }
 379
 380     SM_ASSERT_VALID(ctx, major);
 381
 382 cleanup:
 383     gss_release_buffer_set(&tmpMinor, &innerInputTokens);
 384     gss_release_buffer_set(&tmpMinor, &innerOutputTokens);
 385     if (inputTokenTypes != NULL)
 386         GSSEAP_FREE(inputTokenTypes);
 387     if (outputTokenTypes != NULL)
 388     gss_release_buffer(&tmpMinor, &unwrappedOutputToken);
 389         GSSEAP_FREE(outputTokenTypes);
 390
 391     return major;
 392 }