crypto/evp/pkey_mac.c

   1 /*
   2  * Copyright 2018 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include <string.h>
  11 #include <openssl/err.h>
  12 #include <openssl/evp.h>
  13 #include <openssl/engine.h>
  14 #include <openssl/params.h>
  15 #include <openssl/core_names.h>
  16 #include "internal/evp_int.h"
  17 #include "evp_locl.h"
  18
  19 /* MAC PKEY context structure */
  20
  21 typedef struct {
  22     EVP_MAC_CTX *ctx;
  23
  24     /*
  25      * We know of two MAC types:
  26      *
  27      * 1. those who take a secret in raw form, i.e. raw data as a
  28      *    ASN1_OCTET_STRING embedded in a EVP_PKEY.  So far, that's
  29      *    all of them but CMAC.
  30      * 2. those who take a secret with associated cipher in very generic
  31      *    form, i.e. a complete EVP_MAC_CTX embedded in a PKEY.  So far,
  32      *    only CMAC does this.
  33      *
  34      * (one might wonder why the second form isn't used for all)
  35      */
  36 #define MAC_TYPE_RAW    1   /* HMAC like MAC type (all but CMAC so far) */
  37 #define MAC_TYPE_MAC    2   /* CMAC like MAC type (only CMAC known so far) */
  38     int type;
  39
  40     /* The following is only used for MAC_TYPE_RAW implementations */
  41     struct {
  42         const EVP_MD *md;           /* temp storage of MD */
  43         ASN1_OCTET_STRING ktmp;     /* temp storage for key */
  44     } raw_data;
  45 } MAC_PKEY_CTX;
  46
  47 static void pkey_mac_cleanup(EVP_PKEY_CTX *ctx);
  48
  49 static int pkey_mac_init(EVP_PKEY_CTX *ctx)
  50 {
  51     MAC_PKEY_CTX *hctx;
  52     /* We're being smart and using the same base NIDs for PKEY and for MAC */
  53     int nid = ctx->pmeth->pkey_id;
  54     EVP_MAC *mac = EVP_MAC_fetch(NULL, OBJ_nid2sn(nid), NULL);
  55
  56     if ((hctx = OPENSSL_zalloc(sizeof(*hctx))) == NULL) {
  57         EVPerr(EVP_F_PKEY_MAC_INIT, ERR_R_MALLOC_FAILURE);
  58         return 0;
  59     }
  60
  61     hctx->ctx = EVP_MAC_CTX_new(mac);
  62     if (hctx->ctx == NULL) {
  63         OPENSSL_free(hctx);
  64         return 0;
  65     }
  66
  67     if (nid == EVP_PKEY_CMAC) {
  68         hctx->type = MAC_TYPE_MAC;
  69     } else {
  70         hctx->type = MAC_TYPE_RAW;
  71         hctx->raw_data.ktmp.type = V_ASN1_OCTET_STRING;
  72     }
  73
  74     pkey_mac_cleanup(ctx);
  75     EVP_PKEY_CTX_set_data(ctx, hctx);
  76     ctx->keygen_info_count = 0;
  77
  78     return 1;
  79 }
  80
  81 static int pkey_mac_copy(EVP_PKEY_CTX *dst, const EVP_PKEY_CTX *src)
  82 {
  83     MAC_PKEY_CTX *sctx, *dctx;
  84
  85     sctx = EVP_PKEY_CTX_get_data(src);
  86     if (sctx->ctx->data == NULL)
  87         return 0;
  88
  89     dctx = OPENSSL_zalloc(sizeof(*dctx));
  90     if (dctx == NULL) {
  91         EVPerr(EVP_F_PKEY_MAC_COPY, ERR_R_MALLOC_FAILURE);
  92         return 0;
  93     }
  94
  95     EVP_PKEY_CTX_set_data(dst, dctx);
  96     dst->keygen_info_count = 0;
  97
  98     dctx->ctx = EVP_MAC_CTX_dup(sctx->ctx);
  99     if (dctx->ctx == NULL)
 100         goto err;
 101
 102     /*
 103      * Normally, nothing special would be done with the MAC method.  In
 104      * this particular case, though, the MAC method was fetched internally
 105      * by pkey_mac_init() above or by EVP_PKEY_new_CMAC_key() and passed
 106      * via the EVP_MAC_CTX, so it is effectively like every new EVP_MAC_CTX
 107      * fetches the MAC method anew in this case.  Therefore, its reference
 108      * count must be adjusted here.
 109      */
 110     if (!EVP_MAC_up_ref(EVP_MAC_CTX_mac(dctx->ctx)))
 111         goto err;
 112
 113     dctx->type = sctx->type;
 114
 115     switch (dctx->type) {
 116     case MAC_TYPE_RAW:
 117         dctx->raw_data.md = sctx->raw_data.md;
 118         if (ASN1_STRING_get0_data(&sctx->raw_data.ktmp) != NULL &&
 119             !ASN1_STRING_copy(&dctx->raw_data.ktmp, &sctx->raw_data.ktmp))
 120             goto err;
 121         break;
 122     case MAC_TYPE_MAC:
 123         /* Nothing more to do */
 124         break;
 125     default:
 126         /* This should be dead code */
 127         return 0;
 128     }
 129     return 1;
 130  err:
 131     pkey_mac_cleanup(dst);
 132     return 0;
 133 }
 134
 135 static void pkey_mac_cleanup(EVP_PKEY_CTX *ctx)
 136 {
 137     /*
 138      * For the exact same reasons the MAC reference count is incremented
 139      * in pkey_mac_copy() above, it must be explicitly freed here.
 140      */
 141
 142     MAC_PKEY_CTX *hctx = ctx == NULL ? NULL : EVP_PKEY_CTX_get_data(ctx);
 143
 144     if (hctx != NULL) {
 145         EVP_MAC *mac = EVP_MAC_CTX_mac(hctx->ctx);
 146
 147         switch (hctx->type) {
 148         case MAC_TYPE_RAW:
 149             OPENSSL_clear_free(hctx->raw_data.ktmp.data,
 150                                hctx->raw_data.ktmp.length);
 151             break;
 152         }
 153         EVP_MAC_CTX_free(hctx->ctx);
 154         EVP_MAC_free(mac);
 155         OPENSSL_free(hctx);
 156         EVP_PKEY_CTX_set_data(ctx, NULL);
 157     }
 158 }
 159
 160 static int pkey_mac_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
 161 {
 162     MAC_PKEY_CTX *hctx = EVP_PKEY_CTX_get_data(ctx);
 163     int nid = ctx->pmeth->pkey_id;
 164
 165     switch (hctx->type) {
 166     case MAC_TYPE_RAW:
 167         {
 168             ASN1_OCTET_STRING *hkey = NULL;
 169
 170             if (!hctx->raw_data.ktmp.data)
 171                 return 0;
 172             hkey = ASN1_OCTET_STRING_dup(&hctx->raw_data.ktmp);
 173             if (!hkey)
 174                 return 0;
 175             EVP_PKEY_assign(pkey, nid, hkey);
 176         }
 177         break;
 178     case MAC_TYPE_MAC:
 179         {
 180             EVP_MAC_CTX *cmkey = EVP_MAC_CTX_dup(hctx->ctx);
 181
 182             if (cmkey == NULL)
 183                 return 0;
 184             if (!EVP_MAC_up_ref(EVP_MAC_CTX_mac(hctx->ctx)))
 185                 return 0;
 186             EVP_PKEY_assign(pkey, nid, cmkey);
 187         }
 188         break;
 189     default:
 190         /* This should be dead code */
 191         return 0;
 192     }
 193
 194     return 1;
 195 }
 196
 197 static int int_update(EVP_MD_CTX *ctx, const void *data, size_t count)
 198 {
 199     MAC_PKEY_CTX *hctx = EVP_PKEY_CTX_get_data(EVP_MD_CTX_pkey_ctx(ctx));
 200
 201     if (!EVP_MAC_update(hctx->ctx, data, count))
 202         return 0;
 203     return 1;
 204 }
 205
 206 static int pkey_mac_signctx_init(EVP_PKEY_CTX *ctx, EVP_MD_CTX *mctx)
 207 {
 208     MAC_PKEY_CTX *hctx = EVP_PKEY_CTX_get_data(ctx);
 209     ASN1_OCTET_STRING *key = NULL;
 210     int rv = 1;
 211     /*
 212      * For MACs with the EVP_PKEY_FLAG_SIGCTX_CUSTOM flag set and that
 213      * gets the key passed as an ASN.1 OCTET STRING, we set the key here,
 214      * as this may be only time it's set during a DigestSign.
 215      *
 216      * MACs that pass around the key in form of EVP_MAC_CTX are setting
 217      * the key through other mechanisms.  (this is only CMAC for now)
 218      */
 219     int set_key =
 220         hctx->type == MAC_TYPE_RAW
 221         && (ctx->pmeth->flags & EVP_PKEY_FLAG_SIGCTX_CUSTOM) != 0;
 222
 223     if (set_key) {
 224         if (strcmp(OBJ_nid2sn(EVP_PKEY_id(EVP_PKEY_CTX_get0_pkey(ctx))),
 225                    EVP_MAC_name(EVP_MAC_CTX_mac(hctx->ctx))) != 0)
 226             return 0;
 227         key = EVP_PKEY_get0(EVP_PKEY_CTX_get0_pkey(ctx));
 228         if (key == NULL)
 229             return 0;
 230     }
 231
 232     EVP_MD_CTX_set_flags(mctx, EVP_MD_CTX_FLAG_NO_INIT);
 233     EVP_MD_CTX_set_update_fn(mctx, int_update);
 234
 235     /* Some MACs don't support this control...  that's fine */
 236     {
 237         OSSL_PARAM params[3];
 238         size_t params_n = 0;
 239         int flags = EVP_MD_CTX_test_flags(mctx, ~EVP_MD_CTX_FLAG_NO_INIT);
 240
 241         /* TODO(3.0) "flags" isn't quite right, i.e. a quick hack for now */
 242         params[params_n++] =
 243             OSSL_PARAM_construct_int(OSSL_MAC_PARAM_FLAGS, &flags);
 244         if (set_key)
 245             params[params_n++] =
 246                 OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
 247                                                   key->data, key->length);
 248         params[params_n++] = OSSL_PARAM_construct_end();
 249         rv = EVP_MAC_CTX_set_params(hctx->ctx, params);
 250     }
 251     return rv;
 252 }
 253
 254 static int pkey_mac_signctx(EVP_PKEY_CTX *ctx, unsigned char *sig,
 255                              size_t *siglen, EVP_MD_CTX *mctx)
 256 {
 257     MAC_PKEY_CTX *hctx = EVP_PKEY_CTX_get_data(ctx);
 258
 259     return EVP_MAC_final(hctx->ctx, sig, siglen, EVP_MAC_size(hctx->ctx));
 260 }
 261
 262 static int pkey_mac_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
 263 {
 264     MAC_PKEY_CTX *hctx = EVP_PKEY_CTX_get_data(ctx);
 265
 266     switch (type) {
 267
 268     case EVP_PKEY_CTRL_CIPHER:
 269         switch (hctx->type) {
 270         case MAC_TYPE_RAW:
 271             return -2;       /* The raw types don't support ciphers */
 272         case MAC_TYPE_MAC:
 273             {
 274                 OSSL_PARAM params[3];
 275                 size_t params_n = 0;
 276                 char *ciphname = (char *)OBJ_nid2sn(EVP_CIPHER_nid(p2));
 277                 char *engineid = (char *)ENGINE_get_id(ctx->engine);
 278
 279                 params[params_n++] =
 280                     OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_ENGINE,
 281                                                      engineid,
 282                                                      strlen(engineid) + 1);
 283                 params[params_n++] =
 284                     OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_ALGORITHM,
 285                                                      ciphname,
 286                                                      strlen(ciphname) + 1);
 287                 params[params_n] = OSSL_PARAM_construct_end();
 288
 289                 if (!EVP_MAC_CTX_set_params(hctx->ctx, params)
 290                     || !EVP_MAC_init(hctx->ctx))
 291                     return 0;
 292             }
 293             break;
 294         default:
 295             /* This should be dead code */
 296             return 0;
 297         }
 298         break;
 299
 300     case EVP_PKEY_CTRL_MD:
 301         switch (hctx->type) {
 302         case MAC_TYPE_RAW:
 303             hctx->raw_data.md = p2;
 304             break;
 305         case MAC_TYPE_MAC: {
 306                 EVP_MAC_CTX *new_mac_ctx;
 307
 308                 if (ctx->pkey == NULL)
 309                     return 0;
 310                 new_mac_ctx = EVP_MAC_CTX_dup((EVP_MAC_CTX *)ctx->pkey
 311                                               ->pkey.ptr);
 312                 if (new_mac_ctx == NULL)
 313                     return 0;
 314                 EVP_MAC_CTX_free(hctx->ctx);
 315                 hctx->ctx = new_mac_ctx;
 316             }
 317             break;
 318         default:
 319             /* This should be dead code */
 320             return 0;
 321         }
 322         break;
 323
 324     case EVP_PKEY_CTRL_SET_DIGEST_SIZE:
 325         {
 326             OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };
 327             size_t size = (size_t)p1;
 328             size_t verify = 0;
 329
 330             /*
 331              * We verify that the length is actually set by getting back
 332              * the same parameter and checking that it matches what we
 333              * tried to set.
 334              * TODO(3.0) when we have a more direct mechanism to check if
 335              * a parameter was used, we must refactor this to use that.
 336              */
 337
 338             params[0] =
 339                 OSSL_PARAM_construct_size_t(OSSL_MAC_PARAM_OUTLEN, &size);
 340
 341             if (!EVP_MAC_CTX_set_params(hctx->ctx, params))
 342                 return 0;
 343
 344             params[0] =
 345                 OSSL_PARAM_construct_size_t(OSSL_MAC_PARAM_OUTLEN, &verify);
 346
 347             if (!EVP_MAC_CTX_get_params(hctx->ctx, params))
 348                 return 0;
 349
 350             /*
 351              * Since EVP_MAC_CTX_{get,set}_params() returned successfully,
 352              * we can only assume that the size was ignored, i.e. this
 353              * control is unsupported.
 354              */
 355             if (verify != size)
 356                 return -2;
 357         }
 358         break;
 359     case EVP_PKEY_CTRL_SET_MAC_KEY:
 360         switch (hctx->type) {
 361         case MAC_TYPE_RAW:
 362             if ((!p2 && p1 > 0) || (p1 < -1))
 363                 return 0;
 364             if (!ASN1_OCTET_STRING_set(&hctx->raw_data.ktmp, p2, p1))
 365                 return 0;
 366             break;
 367         case MAC_TYPE_MAC:
 368             {
 369                 OSSL_PARAM params[2];
 370                 size_t params_n = 0;
 371
 372                 params[params_n++] =
 373                     OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
 374                                                       p2, p1);
 375                 params[params_n] = OSSL_PARAM_construct_end();
 376
 377                 return EVP_MAC_CTX_set_params(hctx->ctx, params);
 378             }
 379             break;
 380         default:
 381             /* This should be dead code */
 382             return 0;
 383         }
 384         break;
 385
 386     case EVP_PKEY_CTRL_DIGESTINIT:
 387         switch (hctx->type) {
 388         case MAC_TYPE_RAW:
 389             /* Ensure that we have attached the implementation */
 390             if (!EVP_MAC_init(hctx->ctx))
 391                 return 0;
 392             {
 393                 ASN1_OCTET_STRING *key =
 394                     (ASN1_OCTET_STRING *)ctx->pkey->pkey.ptr;
 395                 OSSL_PARAM params[4];
 396                 size_t params_n = 0;
 397                 char *mdname =
 398                     (char *)OBJ_nid2sn(EVP_MD_nid(hctx->raw_data.md));
 399                 char *engineid = ctx->engine == NULL
 400                     ? NULL : (char *)ENGINE_get_id(ctx->engine);
 401
 402                 if (engineid != NULL) {
 403                     size_t engineid_l = strlen(engineid) + 1;
 404                     params[params_n++] =
 405                         OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_ENGINE,
 406                                                          engineid,
 407                                                          engineid_l);
 408                 }
 409                 params[params_n++] =
 410                     OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_ALGORITHM,
 411                                                      mdname,
 412                                                      strlen(mdname) + 1);
 413                 params[params_n++] =
 414                     OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
 415                                                       key->data, key->length);
 416                 params[params_n] = OSSL_PARAM_construct_end();
 417
 418                 return EVP_MAC_CTX_set_params(hctx->ctx, params);
 419             }
 420             break;
 421         case MAC_TYPE_MAC:
 422             return -2;       /* The mac types don't support ciphers */
 423         default:
 424             /* This should be dead code */
 425             return 0;
 426         }
 427         break;
 428
 429     default:
 430         return -2;
 431
 432     }
 433     return 1;
 434 }
 435
 436 static int pkey_mac_ctrl_str(EVP_PKEY_CTX *ctx,
 437                               const char *type, const char *value)
 438 {
 439     MAC_PKEY_CTX *hctx = EVP_PKEY_CTX_get_data(ctx);
 440     const EVP_MAC *mac = EVP_MAC_CTX_mac(hctx->ctx);
 441     OSSL_PARAM params[2];
 442     int ok = 0;
 443
 444     if (!OSSL_PARAM_allocate_from_text(&params[0],
 445                                        EVP_MAC_CTX_settable_params(mac),
 446                                        type, value, strlen(value) + 1))
 447         return 0;
 448     params[1] = OSSL_PARAM_construct_end();
 449     ok = EVP_MAC_CTX_set_params(hctx->ctx, params);
 450     OPENSSL_free(params[0].data);
 451     return ok;
 452 }
 453
 454 const EVP_PKEY_METHOD cmac_pkey_meth = {
 455     EVP_PKEY_CMAC,
 456     EVP_PKEY_FLAG_SIGCTX_CUSTOM,
 457     pkey_mac_init,
 458     pkey_mac_copy,
 459     pkey_mac_cleanup,
 460
 461     0, 0,
 462
 463     0,
 464     pkey_mac_keygen,
 465
 466     0, 0,
 467
 468     0, 0,
 469
 470     0, 0,
 471
 472     pkey_mac_signctx_init,
 473     pkey_mac_signctx,
 474
 475     0, 0,
 476
 477     0, 0,
 478
 479     0, 0,
 480
 481     0, 0,
 482
 483     pkey_mac_ctrl,
 484     pkey_mac_ctrl_str
 485 };
 486
 487 const EVP_PKEY_METHOD hmac_pkey_meth = {
 488     EVP_PKEY_HMAC,
 489     0,
 490     pkey_mac_init,
 491     pkey_mac_copy,
 492     pkey_mac_cleanup,
 493
 494     0, 0,
 495
 496     0,
 497     pkey_mac_keygen,
 498
 499     0, 0,
 500
 501     0, 0,
 502
 503     0, 0,
 504
 505     pkey_mac_signctx_init,
 506     pkey_mac_signctx,
 507
 508     0, 0,
 509
 510     0, 0,
 511
 512     0, 0,
 513
 514     0, 0,
 515
 516     pkey_mac_ctrl,
 517     pkey_mac_ctrl_str
 518 };
 519
 520 const EVP_PKEY_METHOD siphash_pkey_meth = {
 521     EVP_PKEY_SIPHASH,
 522     EVP_PKEY_FLAG_SIGCTX_CUSTOM,
 523     pkey_mac_init,
 524     pkey_mac_copy,
 525     pkey_mac_cleanup,
 526
 527     0, 0,
 528
 529     0,
 530     pkey_mac_keygen,
 531
 532     0, 0,
 533
 534     0, 0,
 535
 536     0, 0,
 537
 538     pkey_mac_signctx_init,
 539     pkey_mac_signctx,
 540
 541     0, 0,
 542
 543     0, 0,
 544
 545     0, 0,
 546
 547     0, 0,
 548
 549     pkey_mac_ctrl,
 550     pkey_mac_ctrl_str
 551 };
 552
 553 const EVP_PKEY_METHOD poly1305_pkey_meth = {
 554     EVP_PKEY_POLY1305,
 555     EVP_PKEY_FLAG_SIGCTX_CUSTOM,
 556     pkey_mac_init,
 557     pkey_mac_copy,
 558     pkey_mac_cleanup,
 559
 560     0, 0,
 561
 562     0,
 563     pkey_mac_keygen,
 564
 565     0, 0,
 566
 567     0, 0,
 568
 569     0, 0,
 570
 571     pkey_mac_signctx_init,
 572     pkey_mac_signctx,
 573
 574     0, 0,
 575
 576     0, 0,
 577
 578     0, 0,
 579
 580     0, 0,
 581
 582     pkey_mac_ctrl,
 583     pkey_mac_ctrl_str
 584 };