providers/implementations/kdfs/kbkdf.c

   1 /*
   2  * Copyright 2019-2023 The OpenSSL Project Authors. All Rights Reserved.
   3  * Copyright 2019 Red Hat, Inc.
   4  *
   5  * Licensed under the Apache License 2.0 (the "License").  You may not use
   6  * this file except in compliance with the License.  You can obtain a copy
   7  * in the file LICENSE in the source distribution or at
   8  * https://www.openssl.org/source/license.html
   9  */
  10
  11 /*
  12  * This implements https://csrc.nist.gov/publications/detail/sp/800-108/final
  13  * section 5.1 ("counter mode") and section 5.2 ("feedback mode") in both HMAC
  14  * and CMAC.  That document does not name the KDFs it defines; the name is
  15  * derived from
  16  * https://csrc.nist.gov/Projects/Cryptographic-Algorithm-Validation-Program/Key-Derivation
  17  *
  18  * Note that section 5.3 ("double-pipeline mode") is not implemented, though
  19  * it would be possible to do so in the future.
  20  *
  21  * These versions all assume the counter is used.  It would be relatively
  22  * straightforward to expose a configuration handle should the need arise.
  23  *
  24  * Variable names attempt to match those of SP800-108.
  25  */
  26
  27 #include <stdarg.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30
  31 #include <openssl/core_names.h>
  32 #include <openssl/evp.h>
  33 #include <openssl/hmac.h>
  34 #include <openssl/kdf.h>
  35 #include <openssl/params.h>
  36 #include <openssl/proverr.h>
  37
  38 #include "internal/cryptlib.h"
  39 #include "crypto/evp.h"
  40 #include "internal/numbers.h"
  41 #include "internal/endian.h"
  42 #include "prov/implementations.h"
  43 #include "prov/provider_ctx.h"
  44 #include "prov/provider_util.h"
  45 #include "prov/providercommon.h"
  46
  47 #include "internal/e_os.h"
  48 #include "internal/params.h"
  49
  50 #define ossl_min(a, b) ((a) < (b)) ? (a) : (b)
  51
  52 typedef enum {
  53     COUNTER = 0,
  54     FEEDBACK
  55 } kbkdf_mode;
  56
  57 /* Our context structure. */
  58 typedef struct {
  59     void *provctx;
  60     kbkdf_mode mode;
  61     EVP_MAC_CTX *ctx_init;
  62
  63     /* Names are lowercased versions of those found in SP800-108. */
  64     int r;
  65     unsigned char *ki;
  66     size_t ki_len;
  67     unsigned char *label;
  68     size_t label_len;
  69     unsigned char *context;
  70     size_t context_len;
  71     unsigned char *iv;
  72     size_t iv_len;
  73     int use_l;
  74     int is_kmac;
  75     int use_separator;
  76 } KBKDF;
  77
  78 /* Definitions needed for typechecking. */
  79 static OSSL_FUNC_kdf_newctx_fn kbkdf_new;
  80 static OSSL_FUNC_kdf_dupctx_fn kbkdf_dup;
  81 static OSSL_FUNC_kdf_freectx_fn kbkdf_free;
  82 static OSSL_FUNC_kdf_reset_fn kbkdf_reset;
  83 static OSSL_FUNC_kdf_derive_fn kbkdf_derive;
  84 static OSSL_FUNC_kdf_settable_ctx_params_fn kbkdf_settable_ctx_params;
  85 static OSSL_FUNC_kdf_set_ctx_params_fn kbkdf_set_ctx_params;
  86 static OSSL_FUNC_kdf_gettable_ctx_params_fn kbkdf_gettable_ctx_params;
  87 static OSSL_FUNC_kdf_get_ctx_params_fn kbkdf_get_ctx_params;
  88
  89 /* Not all platforms have htobe32(). */
  90 static uint32_t be32(uint32_t host)
  91 {
  92     uint32_t big = 0;
  93     DECLARE_IS_ENDIAN;
  94
  95     if (!IS_LITTLE_ENDIAN)
  96         return host;
  97
  98     big |= (host & 0xff000000) >> 24;
  99     big |= (host & 0x00ff0000) >> 8;
 100     big |= (host & 0x0000ff00) << 8;
 101     big |= (host & 0x000000ff) << 24;
 102     return big;
 103 }
 104
 105 static void init(KBKDF *ctx)
 106 {
 107     ctx->r = 32;
 108     ctx->use_l = 1;
 109     ctx->use_separator = 1;
 110     ctx->is_kmac = 0;
 111 }
 112
 113 static void *kbkdf_new(void *provctx)
 114 {
 115     KBKDF *ctx;
 116
 117     if (!ossl_prov_is_running())
 118         return NULL;
 119
 120     ctx = OPENSSL_zalloc(sizeof(*ctx));
 121     if (ctx == NULL)
 122         return NULL;
 123
 124     ctx->provctx = provctx;
 125     init(ctx);
 126     return ctx;
 127 }
 128
 129 static void kbkdf_free(void *vctx)
 130 {
 131     KBKDF *ctx = (KBKDF *)vctx;
 132
 133     if (ctx != NULL) {
 134         kbkdf_reset(ctx);
 135         OPENSSL_free(ctx);
 136     }
 137 }
 138
 139 static void kbkdf_reset(void *vctx)
 140 {
 141     KBKDF *ctx = (KBKDF *)vctx;
 142     void *provctx = ctx->provctx;
 143
 144     EVP_MAC_CTX_free(ctx->ctx_init);
 145     OPENSSL_clear_free(ctx->context, ctx->context_len);
 146     OPENSSL_clear_free(ctx->label, ctx->label_len);
 147     OPENSSL_clear_free(ctx->ki, ctx->ki_len);
 148     OPENSSL_clear_free(ctx->iv, ctx->iv_len);
 149     memset(ctx, 0, sizeof(*ctx));
 150     ctx->provctx = provctx;
 151     init(ctx);
 152 }
 153
 154 static void *kbkdf_dup(void *vctx)
 155 {
 156     const KBKDF *src = (const KBKDF *)vctx;
 157     KBKDF *dest;
 158
 159     dest = kbkdf_new(src->provctx);
 160     if (dest != NULL) {
 161         dest->ctx_init = EVP_MAC_CTX_dup(src->ctx_init);
 162         if (dest->ctx_init == NULL
 163                 || !ossl_prov_memdup(src->ki, src->ki_len,
 164                                      &dest->ki, &dest->ki_len)
 165                 || !ossl_prov_memdup(src->label, src->label_len,
 166                                      &dest->label, &dest->label_len)
 167                 || !ossl_prov_memdup(src->context, src->context_len,
 168                                      &dest->context, &dest->context_len)
 169                 || !ossl_prov_memdup(src->iv, src->iv_len,
 170                                      &dest->iv, &dest->iv_len))
 171             goto err;
 172         dest->mode = src->mode;
 173         dest->r = src->r;
 174         dest->use_l = src->use_l;
 175         dest->use_separator = src->use_separator;
 176         dest->is_kmac = src->is_kmac;
 177     }
 178     return dest;
 179
 180  err:
 181     kbkdf_free(dest);
 182     return NULL;
 183 }
 184
 185 /* SP800-108 section 5.1 or section 5.2 depending on mode. */
 186 static int derive(EVP_MAC_CTX *ctx_init, kbkdf_mode mode, unsigned char *iv,
 187                   size_t iv_len, unsigned char *label, size_t label_len,
 188                   unsigned char *context, size_t context_len,
 189                   unsigned char *k_i, size_t h, uint32_t l, int has_separator,
 190                   unsigned char *ko, size_t ko_len, int r)
 191 {
 192     int ret = 0;
 193     EVP_MAC_CTX *ctx = NULL;
 194     size_t written = 0, to_write, k_i_len = iv_len;
 195     const unsigned char zero = 0;
 196     uint32_t counter, i;
 197     /*
 198      * From SP800-108:
 199      * The fixed input data is a concatenation of a Label,
 200      * a separation indicator 0x00, the Context, and L.
 201      * One or more of these fixed input data fields may be omitted.
 202      *
 203      * has_separator == 0 means that the separator is omitted.
 204      * Passing a value of l == 0 means that L is omitted.
 205      * The Context and L are omitted automatically if a NULL buffer is passed.
 206      */
 207     int has_l = (l != 0);
 208
 209     /* Setup K(0) for feedback mode. */
 210     if (iv_len > 0)
 211         memcpy(k_i, iv, iv_len);
 212
 213     for (counter = 1; written < ko_len; counter++) {
 214         i = be32(counter);
 215
 216         ctx = EVP_MAC_CTX_dup(ctx_init);
 217         if (ctx == NULL)
 218             goto done;
 219
 220         /* Perform feedback, if appropriate. */
 221         if (mode == FEEDBACK && !EVP_MAC_update(ctx, k_i, k_i_len))
 222             goto done;
 223
 224         if (!EVP_MAC_update(ctx, 4 - (r / 8) + (unsigned char *)&i, r / 8)
 225             || !EVP_MAC_update(ctx, label, label_len)
 226             || (has_separator && !EVP_MAC_update(ctx, &zero, 1))
 227             || !EVP_MAC_update(ctx, context, context_len)
 228             || (has_l && !EVP_MAC_update(ctx, (unsigned char *)&l, 4))
 229             || !EVP_MAC_final(ctx, k_i, NULL, h))
 230             goto done;
 231
 232         to_write = ko_len - written;
 233         memcpy(ko + written, k_i, ossl_min(to_write, h));
 234         written += h;
 235
 236         k_i_len = h;
 237         EVP_MAC_CTX_free(ctx);
 238         ctx = NULL;
 239     }
 240
 241     ret = 1;
 242 done:
 243     EVP_MAC_CTX_free(ctx);
 244     return ret;
 245 }
 246
 247 /* This must be run before the key is set */
 248 static int kmac_init(EVP_MAC_CTX *ctx, const unsigned char *custom, size_t customlen)
 249 {
 250     OSSL_PARAM params[2];
 251
 252     if (custom == NULL || customlen == 0)
 253         return 1;
 254     params[0] = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_CUSTOM,
 255                                                   (void *)custom, customlen);
 256     params[1] = OSSL_PARAM_construct_end();
 257     return EVP_MAC_CTX_set_params(ctx, params) > 0;
 258 }
 259
 260 static int kmac_derive(EVP_MAC_CTX *ctx, unsigned char *out, size_t outlen,
 261                        const unsigned char *context, size_t contextlen)
 262 {
 263     OSSL_PARAM params[2];
 264
 265     params[0] = OSSL_PARAM_construct_size_t(OSSL_MAC_PARAM_SIZE, &outlen);
 266     params[1] = OSSL_PARAM_construct_end();
 267     return EVP_MAC_CTX_set_params(ctx, params) > 0
 268            && EVP_MAC_update(ctx, context, contextlen)
 269            && EVP_MAC_final(ctx, out, NULL, outlen);
 270 }
 271
 272 static int kbkdf_derive(void *vctx, unsigned char *key, size_t keylen,
 273                         const OSSL_PARAM params[])
 274 {
 275     KBKDF *ctx = (KBKDF *)vctx;
 276     int ret = 0;
 277     unsigned char *k_i = NULL;
 278     uint32_t l = 0;
 279     size_t h = 0;
 280     uint64_t counter_max;
 281
 282     if (!ossl_prov_is_running() || !kbkdf_set_ctx_params(ctx, params))
 283         return 0;
 284
 285     /* label, context, and iv are permitted to be empty.  Check everything
 286      * else. */
 287     if (ctx->ctx_init == NULL) {
 288         if (ctx->ki_len == 0 || ctx->ki == NULL) {
 289             ERR_raise(ERR_LIB_PROV, PROV_R_NO_KEY_SET);
 290             return 0;
 291         }
 292         /* Could either be missing MAC or missing message digest or missing
 293          * cipher - arbitrarily, I pick this one. */
 294         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MAC);
 295         return 0;
 296     }
 297
 298     /* Fail if the output length is zero */
 299     if (keylen == 0) {
 300         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
 301         return 0;
 302     }
 303
 304     if (ctx->is_kmac) {
 305         ret = kmac_derive(ctx->ctx_init, key, keylen,
 306                           ctx->context, ctx->context_len);
 307         goto done;
 308     }
 309
 310     h = EVP_MAC_CTX_get_mac_size(ctx->ctx_init);
 311     if (h == 0)
 312         goto done;
 313
 314     if (ctx->iv_len != 0 && ctx->iv_len != h) {
 315         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_SEED_LENGTH);
 316         goto done;
 317     }
 318
 319     if (ctx->mode == COUNTER) {
 320         /* Fail if keylen is too large for r */
 321         counter_max = (uint64_t)1 << (uint64_t)ctx->r;
 322         if ((uint64_t)(keylen / h) >= counter_max) {
 323             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
 324             goto done;
 325         }
 326     }
 327
 328     if (ctx->use_l != 0)
 329         l = be32(keylen * 8);
 330
 331     k_i = OPENSSL_zalloc(h);
 332     if (k_i == NULL)
 333         goto done;
 334
 335     ret = derive(ctx->ctx_init, ctx->mode, ctx->iv, ctx->iv_len, ctx->label,
 336                  ctx->label_len, ctx->context, ctx->context_len, k_i, h, l,
 337                  ctx->use_separator, key, keylen, ctx->r);
 338 done:
 339     if (ret != 1)
 340         OPENSSL_cleanse(key, keylen);
 341     OPENSSL_clear_free(k_i, h);
 342     return ret;
 343 }
 344
 345 static int kbkdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
 346 {
 347     KBKDF *ctx = (KBKDF *)vctx;
 348     OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx);
 349     const OSSL_PARAM *p;
 350
 351     if (params == NULL)
 352         return 1;
 353
 354     if (!ossl_prov_macctx_load_from_params(&ctx->ctx_init, params, NULL,
 355                                            NULL, NULL, libctx))
 356         return 0;
 357     else if (ctx->ctx_init != NULL) {
 358         if (EVP_MAC_is_a(EVP_MAC_CTX_get0_mac(ctx->ctx_init),
 359                          OSSL_MAC_NAME_KMAC128)
 360             || EVP_MAC_is_a(EVP_MAC_CTX_get0_mac(ctx->ctx_init),
 361                             OSSL_MAC_NAME_KMAC256)) {
 362             ctx->is_kmac = 1;
 363         } else if (!EVP_MAC_is_a(EVP_MAC_CTX_get0_mac(ctx->ctx_init),
 364                                  OSSL_MAC_NAME_HMAC)
 365                    && !EVP_MAC_is_a(EVP_MAC_CTX_get0_mac(ctx->ctx_init),
 366                                     OSSL_MAC_NAME_CMAC)) {
 367             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_MAC);
 368             return 0;
 369         }
 370     }
 371
 372     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_MODE);
 373     if (p != NULL
 374         && OPENSSL_strncasecmp("counter", p->data, p->data_size) == 0) {
 375         ctx->mode = COUNTER;
 376     } else if (p != NULL
 377                && OPENSSL_strncasecmp("feedback", p->data, p->data_size) == 0) {
 378         ctx->mode = FEEDBACK;
 379     } else if (p != NULL) {
 380         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_MODE);
 381         return 0;
 382     }
 383
 384     if (ossl_param_get1_octet_string(params, OSSL_KDF_PARAM_KEY,
 385                                      &ctx->ki, &ctx->ki_len) == 0)
 386             return 0;
 387
 388     if (ossl_param_get1_octet_string(params, OSSL_KDF_PARAM_SALT,
 389                                      &ctx->label, &ctx->label_len) == 0)
 390             return 0;
 391
 392     if (ossl_param_get1_concat_octet_string(params, OSSL_KDF_PARAM_INFO,
 393                                             &ctx->context, &ctx->context_len,
 394                                             0) == 0)
 395         return 0;
 396
 397     if (ossl_param_get1_octet_string(params, OSSL_KDF_PARAM_SEED,
 398                                      &ctx->iv, &ctx->iv_len) == 0)
 399             return 0;
 400
 401     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KBKDF_USE_L);
 402     if (p != NULL && !OSSL_PARAM_get_int(p, &ctx->use_l))
 403         return 0;
 404
 405     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KBKDF_R);
 406     if (p != NULL) {
 407         int new_r = 0;
 408
 409         if (!OSSL_PARAM_get_int(p, &new_r))
 410             return 0;
 411         if (new_r != 8 && new_r != 16 && new_r != 24 && new_r != 32)
 412             return 0;
 413         ctx->r = new_r;
 414     }
 415
 416     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KBKDF_USE_SEPARATOR);
 417     if (p != NULL && !OSSL_PARAM_get_int(p, &ctx->use_separator))
 418         return 0;
 419
 420     /* Set up digest context, if we can. */
 421     if (ctx->ctx_init != NULL && ctx->ki_len != 0) {
 422         if ((ctx->is_kmac && !kmac_init(ctx->ctx_init, ctx->label, ctx->label_len))
 423             || !EVP_MAC_init(ctx->ctx_init, ctx->ki, ctx->ki_len, NULL))
 424             return 0;
 425     }
 426     return 1;
 427 }
 428
 429 static const OSSL_PARAM *kbkdf_settable_ctx_params(ossl_unused void *ctx,
 430                                                    ossl_unused void *provctx)
 431 {
 432     static const OSSL_PARAM known_settable_ctx_params[] = {
 433         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_INFO, NULL, 0),
 434         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
 435         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
 436         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SEED, NULL, 0),
 437         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
 438         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_CIPHER, NULL, 0),
 439         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_MAC, NULL, 0),
 440         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_MODE, NULL, 0),
 441         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
 442         OSSL_PARAM_int(OSSL_KDF_PARAM_KBKDF_USE_L, NULL),
 443         OSSL_PARAM_int(OSSL_KDF_PARAM_KBKDF_USE_SEPARATOR, NULL),
 444         OSSL_PARAM_int(OSSL_KDF_PARAM_KBKDF_R, NULL),
 445         OSSL_PARAM_END,
 446     };
 447     return known_settable_ctx_params;
 448 }
 449
 450 static int kbkdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
 451 {
 452     OSSL_PARAM *p;
 453
 454     p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE);
 455     if (p == NULL)
 456         return -2;
 457
 458     /* KBKDF can produce results as large as you like. */
 459     return OSSL_PARAM_set_size_t(p, SIZE_MAX);
 460 }
 461
 462 static const OSSL_PARAM *kbkdf_gettable_ctx_params(ossl_unused void *ctx,
 463                                                    ossl_unused void *provctx)
 464 {
 465     static const OSSL_PARAM known_gettable_ctx_params[] =
 466         { OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL), OSSL_PARAM_END };
 467     return known_gettable_ctx_params;
 468 }
 469
 470 const OSSL_DISPATCH ossl_kdf_kbkdf_functions[] = {
 471     { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kbkdf_new },
 472     { OSSL_FUNC_KDF_DUPCTX, (void(*)(void))kbkdf_dup },
 473     { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kbkdf_free },
 474     { OSSL_FUNC_KDF_RESET, (void(*)(void))kbkdf_reset },
 475     { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kbkdf_derive },
 476     { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
 477       (void(*)(void))kbkdf_settable_ctx_params },
 478     { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kbkdf_set_ctx_params },
 479     { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
 480       (void(*)(void))kbkdf_gettable_ctx_params },
 481     { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kbkdf_get_ctx_params },
 482     OSSL_DISPATCH_END,
 483 };