providers/implementations/rands/drbg_hmac.c

   1 /*
   2  * Copyright 2011-2021 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 <stdlib.h>
  11 #include <string.h>
  12 #include <openssl/crypto.h>
  13 #include <openssl/err.h>
  14 #include <openssl/rand.h>
  15 #include <openssl/proverr.h>
  16 #include "prov/provider_util.h"
  17 #include "internal/thread_once.h"
  18 #include "prov/providercommon.h"
  19 #include "prov/implementations.h"
  20 #include "prov/provider_ctx.h"
  21 #include "drbg_local.h"
  22
  23 static OSSL_FUNC_rand_newctx_fn drbg_hmac_new_wrapper;
  24 static OSSL_FUNC_rand_freectx_fn drbg_hmac_free;
  25 static OSSL_FUNC_rand_instantiate_fn drbg_hmac_instantiate_wrapper;
  26 static OSSL_FUNC_rand_uninstantiate_fn drbg_hmac_uninstantiate_wrapper;
  27 static OSSL_FUNC_rand_generate_fn drbg_hmac_generate_wrapper;
  28 static OSSL_FUNC_rand_reseed_fn drbg_hmac_reseed_wrapper;
  29 static OSSL_FUNC_rand_settable_ctx_params_fn drbg_hmac_settable_ctx_params;
  30 static OSSL_FUNC_rand_set_ctx_params_fn drbg_hmac_set_ctx_params;
  31 static OSSL_FUNC_rand_gettable_ctx_params_fn drbg_hmac_gettable_ctx_params;
  32 static OSSL_FUNC_rand_get_ctx_params_fn drbg_hmac_get_ctx_params;
  33 static OSSL_FUNC_rand_verify_zeroization_fn drbg_hmac_verify_zeroization;
  34
  35 typedef struct rand_drbg_hmac_st {
  36     EVP_MAC_CTX *ctx;            /* H(x) = HMAC_hash OR H(x) = KMAC */
  37     PROV_DIGEST digest;          /* H(x) = hash(x) */
  38     size_t blocklen;
  39     unsigned char K[EVP_MAX_MD_SIZE];
  40     unsigned char V[EVP_MAX_MD_SIZE];
  41 } PROV_DRBG_HMAC;
  42
  43 /*
  44  * Called twice by SP800-90Ar1 10.1.2.2 HMAC_DRBG_Update_Process.
  45  *
  46  * hmac is an object that holds the input/output Key and Value (K and V).
  47  * inbyte is 0x00 on the first call and 0x01 on the second call.
  48  * in1, in2, in3 are optional inputs that can be NULL.
  49  * in1len, in2len, in3len are the lengths of the input buffers.
  50  *
  51  * The returned K,V is:
  52  *   hmac->K = HMAC(hmac->K, hmac->V || inbyte || [in1] || [in2] || [in3])
  53  *   hmac->V = HMAC(hmac->K, hmac->V)
  54  *
  55  * Returns zero if an error occurs otherwise it returns 1.
  56  */
  57 static int do_hmac(PROV_DRBG_HMAC *hmac, unsigned char inbyte,
  58                    const unsigned char *in1, size_t in1len,
  59                    const unsigned char *in2, size_t in2len,
  60                    const unsigned char *in3, size_t in3len)
  61 {
  62     EVP_MAC_CTX *ctx = hmac->ctx;
  63
  64     if (!EVP_MAC_init(ctx, hmac->K, hmac->blocklen, NULL)
  65             /* K = HMAC(K, V || inbyte || [in1] || [in2] || [in3]) */
  66             || !EVP_MAC_update(ctx, hmac->V, hmac->blocklen)
  67             || !EVP_MAC_update(ctx, &inbyte, 1)
  68             || !(in1 == NULL || in1len == 0 || EVP_MAC_update(ctx, in1, in1len))
  69             || !(in2 == NULL || in2len == 0 || EVP_MAC_update(ctx, in2, in2len))
  70             || !(in3 == NULL || in3len == 0 || EVP_MAC_update(ctx, in3, in3len))
  71             || !EVP_MAC_final(ctx, hmac->K, NULL, sizeof(hmac->K)))
  72         return 0;
  73
  74    /* V = HMAC(K, V) */
  75     return EVP_MAC_init(ctx, hmac->K, hmac->blocklen, NULL)
  76            && EVP_MAC_update(ctx, hmac->V, hmac->blocklen)
  77            && EVP_MAC_final(ctx, hmac->V, NULL, sizeof(hmac->V));
  78 }
  79
  80 /*
  81  * SP800-90Ar1 10.1.2.2 HMAC_DRBG_Update_Process
  82  *
  83  *
  84  * Updates the drbg objects Key(K) and Value(V) using the following algorithm:
  85  *   K,V = do_hmac(hmac, 0, in1, in2, in3)
  86  *   if (any input is not NULL)
  87  *     K,V = do_hmac(hmac, 1, in1, in2, in3)
  88  *
  89  * where in1, in2, in3 are optional input buffers that can be NULL.
  90  *       in1len, in2len, in3len are the lengths of the input buffers.
  91  *
  92  * Returns zero if an error occurs otherwise it returns 1.
  93  */
  94 static int drbg_hmac_update(PROV_DRBG *drbg,
  95                             const unsigned char *in1, size_t in1len,
  96                             const unsigned char *in2, size_t in2len,
  97                             const unsigned char *in3, size_t in3len)
  98 {
  99     PROV_DRBG_HMAC *hmac = (PROV_DRBG_HMAC *)drbg->data;
 100
 101     /* (Steps 1-2) K = HMAC(K, V||0x00||provided_data). V = HMAC(K,V) */
 102     if (!do_hmac(hmac, 0x00, in1, in1len, in2, in2len, in3, in3len))
 103         return 0;
 104     /* (Step 3) If provided_data == NULL then return (K,V) */
 105     if (in1len == 0 && in2len == 0 && in3len == 0)
 106         return 1;
 107     /* (Steps 4-5) K = HMAC(K, V||0x01||provided_data). V = HMAC(K,V) */
 108     return do_hmac(hmac, 0x01, in1, in1len, in2, in2len, in3, in3len);
 109 }
 110
 111 /*
 112  * SP800-90Ar1 10.1.2.3 HMAC_DRBG_Instantiate_Process:
 113  *
 114  * This sets the drbg Key (K) to all zeros, and Value (V) to all 1's.
 115  * and then calls (K,V) = drbg_hmac_update() with input parameters:
 116  *   ent = entropy data (Can be NULL) of length ent_len.
 117  *   nonce = nonce data (Can be NULL) of length nonce_len.
 118  *   pstr = personalization data (Can be NULL) of length pstr_len.
 119  *
 120  * Returns zero if an error occurs otherwise it returns 1.
 121  */
 122 static int drbg_hmac_instantiate(PROV_DRBG *drbg,
 123                                  const unsigned char *ent, size_t ent_len,
 124                                  const unsigned char *nonce, size_t nonce_len,
 125                                  const unsigned char *pstr, size_t pstr_len)
 126 {
 127     PROV_DRBG_HMAC *hmac = (PROV_DRBG_HMAC *)drbg->data;
 128
 129     if (hmac->ctx == NULL) {
 130         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MAC);
 131         return 0;
 132     }
 133
 134     /* (Step 2) Key = 0x00 00...00 */
 135     memset(hmac->K, 0x00, hmac->blocklen);
 136     /* (Step 3) V = 0x01 01...01 */
 137     memset(hmac->V, 0x01, hmac->blocklen);
 138     /* (Step 4) (K,V) = HMAC_DRBG_Update(entropy||nonce||pers string, K, V) */
 139     return drbg_hmac_update(drbg, ent, ent_len, nonce, nonce_len, pstr,
 140                             pstr_len);
 141 }
 142
 143 static int drbg_hmac_instantiate_wrapper(void *vdrbg, unsigned int strength,
 144                                          int prediction_resistance,
 145                                          const unsigned char *pstr,
 146                                          size_t pstr_len,
 147                                          const OSSL_PARAM params[])
 148 {
 149     PROV_DRBG *drbg = (PROV_DRBG *)vdrbg;
 150
 151     if (!ossl_prov_is_running() || !drbg_hmac_set_ctx_params(drbg, params))
 152         return 0;
 153     return ossl_prov_drbg_instantiate(drbg, strength, prediction_resistance,
 154                                       pstr, pstr_len);
 155 }
 156
 157 /*
 158  * SP800-90Ar1 10.1.2.4 HMAC_DRBG_Reseed_Process:
 159  *
 160  * Reseeds the drbg's Key (K) and Value (V) by calling
 161  * (K,V) = drbg_hmac_update() with the following input parameters:
 162  *   ent = entropy input data (Can be NULL) of length ent_len.
 163  *   adin = additional input data (Can be NULL) of length adin_len.
 164  *
 165  * Returns zero if an error occurs otherwise it returns 1.
 166  */
 167 static int drbg_hmac_reseed(PROV_DRBG *drbg,
 168                             const unsigned char *ent, size_t ent_len,
 169                             const unsigned char *adin, size_t adin_len)
 170 {
 171     /* (Step 2) (K,V) = HMAC_DRBG_Update(entropy||additional_input, K, V) */
 172     return drbg_hmac_update(drbg, ent, ent_len, adin, adin_len, NULL, 0);
 173 }
 174
 175 static int drbg_hmac_reseed_wrapper(void *vdrbg, int prediction_resistance,
 176                                     const unsigned char *ent, size_t ent_len,
 177                                     const unsigned char *adin, size_t adin_len)
 178 {
 179     PROV_DRBG *drbg = (PROV_DRBG *)vdrbg;
 180
 181     return ossl_prov_drbg_reseed(drbg, prediction_resistance, ent, ent_len,
 182                                  adin, adin_len);
 183 }
 184
 185 /*
 186  * SP800-90Ar1 10.1.2.5 HMAC_DRBG_Generate_Process:
 187  *
 188  * Generates pseudo random bytes and updates the internal K,V for the drbg.
 189  * out is a buffer to fill with outlen bytes of pseudo random data.
 190  * adin is an additional_input string of size adin_len that may be NULL.
 191  *
 192  * Returns zero if an error occurs otherwise it returns 1.
 193  */
 194 static int drbg_hmac_generate(PROV_DRBG *drbg,
 195                               unsigned char *out, size_t outlen,
 196                               const unsigned char *adin, size_t adin_len)
 197 {
 198     PROV_DRBG_HMAC *hmac = (PROV_DRBG_HMAC *)drbg->data;
 199     EVP_MAC_CTX *ctx = hmac->ctx;
 200     const unsigned char *temp = hmac->V;
 201
 202     /* (Step 2) if adin != NULL then (K,V) = HMAC_DRBG_Update(adin, K, V) */
 203     if (adin != NULL
 204             && adin_len > 0
 205             && !drbg_hmac_update(drbg, adin, adin_len, NULL, 0, NULL, 0))
 206         return 0;
 207
 208     /*
 209      * (Steps 3-5) temp = NULL
 210      *             while (len(temp) < outlen) {
 211      *                 V = HMAC(K, V)
 212      *                 temp = temp || V
 213      *             }
 214      */
 215     for (;;) {
 216         if (!EVP_MAC_init(ctx, hmac->K, hmac->blocklen, NULL)
 217             || !EVP_MAC_update(ctx, temp, hmac->blocklen))
 218             return 0;
 219
 220         if (outlen > hmac->blocklen) {
 221             if (!EVP_MAC_final(ctx, out, NULL, outlen))
 222                 return 0;
 223             temp = out;
 224         } else {
 225             if (!EVP_MAC_final(ctx, hmac->V, NULL, sizeof(hmac->V)))
 226                 return 0;
 227             memcpy(out, hmac->V, outlen);
 228             break;
 229         }
 230         out += hmac->blocklen;
 231         outlen -= hmac->blocklen;
 232     }
 233     /* (Step 6) (K,V) = HMAC_DRBG_Update(adin, K, V) */
 234     if (!drbg_hmac_update(drbg, adin, adin_len, NULL, 0, NULL, 0))
 235         return 0;
 236
 237     return 1;
 238 }
 239
 240 static int drbg_hmac_generate_wrapper
 241     (void *vdrbg, unsigned char *out, size_t outlen, unsigned int strength,
 242      int prediction_resistance, const unsigned char *adin, size_t adin_len)
 243 {
 244     PROV_DRBG *drbg = (PROV_DRBG *)vdrbg;
 245
 246     return ossl_prov_drbg_generate(drbg, out, outlen, strength,
 247                                    prediction_resistance, adin, adin_len);
 248 }
 249
 250 static int drbg_hmac_uninstantiate(PROV_DRBG *drbg)
 251 {
 252     PROV_DRBG_HMAC *hmac = (PROV_DRBG_HMAC *)drbg->data;
 253
 254     OPENSSL_cleanse(hmac->K, sizeof(hmac->K));
 255     OPENSSL_cleanse(hmac->V, sizeof(hmac->V));
 256     return ossl_prov_drbg_uninstantiate(drbg);
 257 }
 258
 259 static int drbg_hmac_uninstantiate_wrapper(void *vdrbg)
 260 {
 261     return drbg_hmac_uninstantiate((PROV_DRBG *)vdrbg);
 262 }
 263
 264 static int drbg_hmac_verify_zeroization(void *vdrbg)
 265 {
 266     PROV_DRBG *drbg = (PROV_DRBG *)vdrbg;
 267     PROV_DRBG_HMAC *hmac = (PROV_DRBG_HMAC *)drbg->data;
 268
 269     PROV_DRBG_VERYIFY_ZEROIZATION(hmac->K);
 270     PROV_DRBG_VERYIFY_ZEROIZATION(hmac->V);
 271     return 1;
 272 }
 273
 274 static int drbg_hmac_new(PROV_DRBG *drbg)
 275 {
 276     PROV_DRBG_HMAC *hmac;
 277
 278     hmac = OPENSSL_secure_zalloc(sizeof(*hmac));
 279     if (hmac == NULL) {
 280         ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
 281         return 0;
 282     }
 283
 284     drbg->data = hmac;
 285     /* See SP800-57 Part1 Rev4 5.6.1 Table 3 */
 286     drbg->max_entropylen = DRBG_MAX_LENGTH;
 287     drbg->max_noncelen = DRBG_MAX_LENGTH;
 288     drbg->max_perslen = DRBG_MAX_LENGTH;
 289     drbg->max_adinlen = DRBG_MAX_LENGTH;
 290
 291     /* Maximum number of bits per request = 2^19  = 2^16 bytes */
 292     drbg->max_request = 1 << 16;
 293     return 1;
 294 }
 295
 296 static void *drbg_hmac_new_wrapper(void *provctx, void *parent,
 297                                    const OSSL_DISPATCH *parent_dispatch)
 298 {
 299     return ossl_rand_drbg_new(provctx, parent, parent_dispatch, &drbg_hmac_new,
 300                               &drbg_hmac_instantiate, &drbg_hmac_uninstantiate,
 301                               &drbg_hmac_reseed, &drbg_hmac_generate);
 302 }
 303
 304 static void drbg_hmac_free(void *vdrbg)
 305 {
 306     PROV_DRBG *drbg = (PROV_DRBG *)vdrbg;
 307     PROV_DRBG_HMAC *hmac;
 308
 309     if (drbg != NULL && (hmac = (PROV_DRBG_HMAC *)drbg->data) != NULL) {
 310         EVP_MAC_CTX_free(hmac->ctx);
 311         ossl_prov_digest_reset(&hmac->digest);
 312         OPENSSL_secure_clear_free(hmac, sizeof(*hmac));
 313     }
 314     ossl_rand_drbg_free(drbg);
 315 }
 316
 317 static int drbg_hmac_get_ctx_params(void *vdrbg, OSSL_PARAM params[])
 318 {
 319     PROV_DRBG *drbg = (PROV_DRBG *)vdrbg;
 320     PROV_DRBG_HMAC *hmac = (PROV_DRBG_HMAC *)drbg->data;
 321     const char *name;
 322     const EVP_MD *md;
 323     OSSL_PARAM *p;
 324
 325     p = OSSL_PARAM_locate(params, OSSL_DRBG_PARAM_MAC);
 326     if (p != NULL) {
 327         if (hmac->ctx == NULL)
 328             return 0;
 329         name = EVP_MAC_get0_name(EVP_MAC_CTX_get0_mac(hmac->ctx));
 330         if (!OSSL_PARAM_set_utf8_string(p, name))
 331             return 0;
 332     }
 333
 334     p = OSSL_PARAM_locate(params, OSSL_DRBG_PARAM_DIGEST);
 335     if (p != NULL) {
 336         md = ossl_prov_digest_md(&hmac->digest);
 337         if (md == NULL || !OSSL_PARAM_set_utf8_string(p, EVP_MD_get0_name(md)))
 338             return 0;
 339     }
 340
 341     return ossl_drbg_get_ctx_params(drbg, params);
 342 }
 343
 344 static const OSSL_PARAM *drbg_hmac_gettable_ctx_params(ossl_unused void *vctx,
 345                                                        ossl_unused void *p_ctx)
 346 {
 347     static const OSSL_PARAM known_gettable_ctx_params[] = {
 348         OSSL_PARAM_utf8_string(OSSL_DRBG_PARAM_MAC, NULL, 0),
 349         OSSL_PARAM_utf8_string(OSSL_DRBG_PARAM_DIGEST, NULL, 0),
 350         OSSL_PARAM_DRBG_GETTABLE_CTX_COMMON,
 351         OSSL_PARAM_END
 352     };
 353     return known_gettable_ctx_params;
 354 }
 355
 356 static int drbg_hmac_set_ctx_params(void *vctx, const OSSL_PARAM params[])
 357 {
 358     PROV_DRBG *ctx = (PROV_DRBG *)vctx;
 359     PROV_DRBG_HMAC *hmac = (PROV_DRBG_HMAC *)ctx->data;
 360     OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx);
 361     const EVP_MD *md;
 362
 363     if (!ossl_prov_digest_load_from_params(&hmac->digest, params, libctx))
 364         return 0;
 365
 366     /*
 367      * Confirm digest is allowed. We allow all digests that are not XOF
 368      * (such as SHAKE).  In FIPS mode, the fetch will fail for non-approved
 369      * digests.
 370      */
 371     md = ossl_prov_digest_md(&hmac->digest);
 372     if (md != NULL && (EVP_MD_get_flags(md) & EVP_MD_FLAG_XOF) != 0) {
 373         ERR_raise(ERR_LIB_PROV, PROV_R_XOF_DIGESTS_NOT_ALLOWED);
 374         return 0;
 375     }
 376
 377     if (!ossl_prov_macctx_load_from_params(&hmac->ctx, params,
 378                                            NULL, NULL, NULL, libctx))
 379         return 0;
 380
 381     if (hmac->ctx != NULL) {
 382         /* These are taken from SP 800-90 10.1 Table 2 */
 383         hmac->blocklen = EVP_MD_get_size(md);
 384         /* See SP800-57 Part1 Rev4 5.6.1 Table 3 */
 385         ctx->strength = 64 * (int)(hmac->blocklen >> 3);
 386         if (ctx->strength > 256)
 387             ctx->strength = 256;
 388         ctx->seedlen = hmac->blocklen;
 389         ctx->min_entropylen = ctx->strength / 8;
 390         ctx->min_noncelen = ctx->min_entropylen / 2;
 391     }
 392
 393     return ossl_drbg_set_ctx_params(ctx, params);
 394 }
 395
 396 static const OSSL_PARAM *drbg_hmac_settable_ctx_params(ossl_unused void *vctx,
 397                                                        ossl_unused void *p_ctx)
 398 {
 399     static const OSSL_PARAM known_settable_ctx_params[] = {
 400         OSSL_PARAM_utf8_string(OSSL_DRBG_PARAM_PROPERTIES, NULL, 0),
 401         OSSL_PARAM_utf8_string(OSSL_DRBG_PARAM_DIGEST, NULL, 0),
 402         OSSL_PARAM_utf8_string(OSSL_DRBG_PARAM_MAC, NULL, 0),
 403         OSSL_PARAM_DRBG_SETTABLE_CTX_COMMON,
 404         OSSL_PARAM_END
 405     };
 406     return known_settable_ctx_params;
 407 }
 408
 409 const OSSL_DISPATCH ossl_drbg_ossl_hmac_functions[] = {
 410     { OSSL_FUNC_RAND_NEWCTX, (void(*)(void))drbg_hmac_new_wrapper },
 411     { OSSL_FUNC_RAND_FREECTX, (void(*)(void))drbg_hmac_free },
 412     { OSSL_FUNC_RAND_INSTANTIATE,
 413       (void(*)(void))drbg_hmac_instantiate_wrapper },
 414     { OSSL_FUNC_RAND_UNINSTANTIATE,
 415       (void(*)(void))drbg_hmac_uninstantiate_wrapper },
 416     { OSSL_FUNC_RAND_GENERATE, (void(*)(void))drbg_hmac_generate_wrapper },
 417     { OSSL_FUNC_RAND_RESEED, (void(*)(void))drbg_hmac_reseed_wrapper },
 418     { OSSL_FUNC_RAND_ENABLE_LOCKING, (void(*)(void))ossl_drbg_enable_locking },
 419     { OSSL_FUNC_RAND_LOCK, (void(*)(void))ossl_drbg_lock },
 420     { OSSL_FUNC_RAND_UNLOCK, (void(*)(void))ossl_drbg_unlock },
 421     { OSSL_FUNC_RAND_SETTABLE_CTX_PARAMS,
 422       (void(*)(void))drbg_hmac_settable_ctx_params },
 423     { OSSL_FUNC_RAND_SET_CTX_PARAMS, (void(*)(void))drbg_hmac_set_ctx_params },
 424     { OSSL_FUNC_RAND_GETTABLE_CTX_PARAMS,
 425       (void(*)(void))drbg_hmac_gettable_ctx_params },
 426     { OSSL_FUNC_RAND_GET_CTX_PARAMS, (void(*)(void))drbg_hmac_get_ctx_params },
 427     { OSSL_FUNC_RAND_VERIFY_ZEROIZATION,
 428       (void(*)(void))drbg_hmac_verify_zeroization },
 429     { OSSL_FUNC_RAND_GET_SEED, (void(*)(void))ossl_drbg_get_seed },
 430     { OSSL_FUNC_RAND_CLEAR_SEED, (void(*)(void))ossl_drbg_clear_seed },
 431     { 0, NULL }
 432 };