providers/implementations/kdfs/kbkdf.c

   1 /*
   2  * Copyright 2019-2021 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
  49 #define ossl_min(a, b) ((a) < (b)) ? (a) : (b)
  50
  51 typedef enum {
  52     COUNTER = 0,
  53     FEEDBACK
  54 } kbkdf_mode;
  55
  56 /* Our context structure. */
  57 typedef struct {
  58     void *provctx;
  59     kbkdf_mode mode;
  60     EVP_MAC_CTX *ctx_init;
  61
  62     /* Names are lowercased versions of those found in SP800-108. */
  63     int r;
  64     unsigned char *ki;
  65     size_t ki_len;
  66     unsigned char *label;
  67     size_t label_len;
  68     unsigned char *context;
  69     size_t context_len;
  70     unsigned char *iv;
  71     size_t iv_len;
  72     int use_l;
  73     int use_separator;
  74 } KBKDF;
  75
  76 /* Definitions needed for typechecking. */
  77 static OSSL_FUNC_kdf_newctx_fn kbkdf_new;
  78 static OSSL_FUNC_kdf_newctx_fn kbkdf_dup;
  79 static OSSL_FUNC_kdf_freectx_fn kbkdf_free;
  80 static OSSL_FUNC_kdf_reset_fn kbkdf_reset;
  81 static OSSL_FUNC_kdf_derive_fn kbkdf_derive;
  82 static OSSL_FUNC_kdf_settable_ctx_params_fn kbkdf_settable_ctx_params;
  83 static OSSL_FUNC_kdf_set_ctx_params_fn kbkdf_set_ctx_params;
  84 static OSSL_FUNC_kdf_gettable_ctx_params_fn kbkdf_gettable_ctx_params;
  85 static OSSL_FUNC_kdf_get_ctx_params_fn kbkdf_get_ctx_params;
  86
  87 /* Not all platforms have htobe32(). */
  88 static uint32_t be32(uint32_t host)
  89 {
  90     uint32_t big = 0;
  91     DECLARE_IS_ENDIAN;
  92
  93     if (!IS_LITTLE_ENDIAN)
  94         return host;
  95
  96     big |= (host & 0xff000000) >> 24;
  97     big |= (host & 0x00ff0000) >> 8;
  98     big |= (host & 0x0000ff00) << 8;
  99     big |= (host & 0x000000ff) << 24;
 100     return big;
 101 }
 102
 103 static void init(KBKDF *ctx)
 104 {
 105     ctx->r = 32;
 106     ctx->use_l = 1;
 107     ctx->use_separator = 1;
 108 }
 109
 110 static void *kbkdf_new(void *provctx)
 111 {
 112     KBKDF *ctx;
 113
 114     if (!ossl_prov_is_running())
 115         return NULL;
 116
 117     ctx = OPENSSL_zalloc(sizeof(*ctx));
 118     if (ctx == NULL) {
 119         ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
 120         return NULL;
 121     }
 122
 123     ctx->provctx = provctx;
 124     init(ctx);
 125     return ctx;
 126 }
 127
 128 static void kbkdf_free(void *vctx)
 129 {
 130     KBKDF *ctx = (KBKDF *)vctx;
 131
 132     if (ctx != NULL) {
 133         kbkdf_reset(ctx);
 134         OPENSSL_free(ctx);
 135     }
 136 }
 137
 138 static void kbkdf_reset(void *vctx)
 139 {
 140     KBKDF *ctx = (KBKDF *)vctx;
 141     void *provctx = ctx->provctx;
 142
 143     EVP_MAC_CTX_free(ctx->ctx_init);
 144     OPENSSL_clear_free(ctx->context, ctx->context_len);
 145     OPENSSL_clear_free(ctx->label, ctx->label_len);
 146     OPENSSL_clear_free(ctx->ki, ctx->ki_len);
 147     OPENSSL_clear_free(ctx->iv, ctx->iv_len);
 148     memset(ctx, 0, sizeof(*ctx));
 149     ctx->provctx = provctx;
 150     init(ctx);
 151 }
 152
 153 static void *kbkdf_dup(void *vctx)
 154 {
 155     const KBKDF *src = (const KBKDF *)vctx;
 156     KBKDF *dest;
 157
 158     dest = kbkdf_new(src->provctx);
 159     if (dest != NULL) {
 160         dest->ctx_init = EVP_MAC_CTX_dup(src->ctx_init);
 161         if (dest->ctx_init == NULL
 162                 || !ossl_prov_memdup(src->ki, src->ki_len,
 163                                      &dest->ki, &dest->ki_len)
 164                 || !ossl_prov_memdup(src->label, src->label_len,
 165                                      &dest->label, &dest->label_len)
 166                 || !ossl_prov_memdup(src->context, src->context_len,
 167                                      &dest->context, &dest->context_len)
 168                 || !ossl_prov_memdup(src->iv, src->iv_len,
 169                                      &dest->iv, &dest->iv_len))
 170             goto err;
 171         dest->mode = src->mode;
 172         dest->r = src->r;
 173         dest->use_l = src->use_l;
 174         dest->use_separator = src->use_separator;
 175     }
 176     return dest;
 177
 178  err:
 179     kbkdf_free(dest);
 180     return NULL;
 181 }
 182
 183 /* SP800-108 section 5.1 or section 5.2 depending on mode. */
 184 static int derive(EVP_MAC_CTX *ctx_init, kbkdf_mode mode, unsigned char *iv,
 185                   size_t iv_len, unsigned char *label, size_t label_len,
 186                   unsigned char *context, size_t context_len,
 187                   unsigned char *k_i, size_t h, uint32_t l, int has_separator,
 188                   unsigned char *ko, size_t ko_len, int r)
 189 {
 190     int ret = 0;
 191     EVP_MAC_CTX *ctx = NULL;
 192     size_t written = 0, to_write, k_i_len = iv_len;
 193     const unsigned char zero = 0;
 194     uint32_t counter, i;
 195     /*
 196      * From SP800-108:
 197      * The fixed input data is a concatenation of a Label,
 198      * a separation indicator 0x00, the Context, and L.
 199      * One or more of these fixed input data fields may be omitted.
 200      *
 201      * has_separator == 0 means that the separator is omitted.
 202      * Passing a value of l == 0 means that L is omitted.
 203      * The Context and L are omitted automatically if a NULL buffer is passed.
 204      */
 205     int has_l = (l != 0);
 206
 207     /* Setup K(0) for feedback mode. */
 208     if (iv_len > 0)
 209         memcpy(k_i, iv, iv_len);
 210
 211     for (counter = 1; written < ko_len; counter++) {
 212         i = be32(counter);
 213
 214         ctx = EVP_MAC_CTX_dup(ctx_init);
 215         if (ctx == NULL)
 216             goto done;
 217
 218         /* Perform feedback, if appropriate. */
 219         if (mode == FEEDBACK && !EVP_MAC_update(ctx, k_i, k_i_len))
 220             goto done;
 221
 222         if (!EVP_MAC_update(ctx, 4 - (r / 8) + (unsigned char *)&i, r / 8)
 223             || !EVP_MAC_update(ctx, label, label_len)
 224             || (has_separator && !EVP_MAC_update(ctx, &zero, 1))
 225             || !EVP_MAC_update(ctx, context, context_len)
 226             || (has_l && !EVP_MAC_update(ctx, (unsigned char *)&l, 4))
 227             || !EVP_MAC_final(ctx, k_i, NULL, h))
 228             goto done;
 229
 230         to_write = ko_len - written;
 231         memcpy(ko + written, k_i, ossl_min(to_write, h));
 232         written += h;
 233
 234         k_i_len = h;
 235         EVP_MAC_CTX_free(ctx);
 236         ctx = NULL;
 237     }
 238
 239     ret = 1;
 240 done:
 241     EVP_MAC_CTX_free(ctx);
 242     return ret;
 243 }
 244
 245 static int kbkdf_derive(void *vctx, unsigned char *key, size_t keylen,
 246                         const OSSL_PARAM params[])
 247 {
 248     KBKDF *ctx = (KBKDF *)vctx;
 249     int ret = 0;
 250     unsigned char *k_i = NULL;
 251     uint32_t l = 0;
 252     size_t h = 0;
 253     uint64_t counter_max;
 254
 255     if (!ossl_prov_is_running() || !kbkdf_set_ctx_params(ctx, params))
 256         return 0;
 257
 258     /* label, context, and iv are permitted to be empty.  Check everything
 259      * else. */
 260     if (ctx->ctx_init == NULL) {
 261         if (ctx->ki_len == 0 || ctx->ki == NULL) {
 262             ERR_raise(ERR_LIB_PROV, PROV_R_NO_KEY_SET);
 263             return 0;
 264         }
 265         /* Could either be missing MAC or missing message digest or missing
 266          * cipher - arbitrarily, I pick this one. */
 267         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MAC);
 268         return 0;
 269     }
 270
 271     /* Fail if the output length is zero */
 272     if (keylen == 0) {
 273         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
 274         return 0;
 275     }
 276
 277     h = EVP_MAC_CTX_get_mac_size(ctx->ctx_init);
 278     if (h == 0)
 279         goto done;
 280     if (ctx->iv_len != 0 && ctx->iv_len != h) {
 281         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_SEED_LENGTH);
 282         goto done;
 283     }
 284
 285     if (ctx->mode == COUNTER) {
 286         /* Fail if keylen is too large for r */
 287         counter_max = (uint64_t)1 << (uint64_t)ctx->r;
 288         if ((uint64_t)(keylen / h) >= counter_max) {
 289             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
 290             goto done;
 291         }
 292     }
 293
 294     if (ctx->use_l != 0)
 295         l = be32(keylen * 8);
 296
 297     k_i = OPENSSL_zalloc(h);
 298     if (k_i == NULL)
 299         goto done;
 300
 301     ret = derive(ctx->ctx_init, ctx->mode, ctx->iv, ctx->iv_len, ctx->label,
 302                  ctx->label_len, ctx->context, ctx->context_len, k_i, h, l,
 303                  ctx->use_separator, key, keylen, ctx->r);
 304 done:
 305     if (ret != 1)
 306         OPENSSL_cleanse(key, keylen);
 307     OPENSSL_clear_free(k_i, h);
 308     return ret;
 309 }
 310
 311 static int kbkdf_set_buffer(unsigned char **out, size_t *out_len,
 312                             const OSSL_PARAM *p)
 313 {
 314     if (p->data == NULL || p->data_size == 0)
 315         return 1;
 316
 317     OPENSSL_clear_free(*out, *out_len);
 318     *out = NULL;
 319     return OSSL_PARAM_get_octet_string(p, (void **)out, 0, out_len);
 320 }
 321
 322 static int kbkdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
 323 {
 324     KBKDF *ctx = (KBKDF *)vctx;
 325     OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx);
 326     const OSSL_PARAM *p;
 327
 328     if (params == NULL)
 329         return 1;
 330
 331     if (!ossl_prov_macctx_load_from_params(&ctx->ctx_init, params, NULL,
 332                                            NULL, NULL, libctx))
 333         return 0;
 334     else if (ctx->ctx_init != NULL
 335              && !EVP_MAC_is_a(EVP_MAC_CTX_get0_mac(ctx->ctx_init),
 336                               OSSL_MAC_NAME_HMAC)
 337              && !EVP_MAC_is_a(EVP_MAC_CTX_get0_mac(ctx->ctx_init),
 338                               OSSL_MAC_NAME_CMAC)) {
 339         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_MAC);
 340         return 0;
 341     }
 342
 343     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_MODE);
 344     if (p != NULL && strncasecmp("counter", p->data, p->data_size) == 0) {
 345         ctx->mode = COUNTER;
 346     } else if (p != NULL
 347                && strncasecmp("feedback", p->data, p->data_size) == 0) {
 348         ctx->mode = FEEDBACK;
 349     } else if (p != NULL) {
 350         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_MODE);
 351         return 0;
 352     }
 353
 354     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY);
 355     if (p != NULL && !kbkdf_set_buffer(&ctx->ki, &ctx->ki_len, p))
 356         return 0;
 357
 358     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT);
 359     if (p != NULL && !kbkdf_set_buffer(&ctx->label, &ctx->label_len, p))
 360         return 0;
 361
 362     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_INFO);
 363     if (p != NULL && !kbkdf_set_buffer(&ctx->context, &ctx->context_len, p))
 364         return 0;
 365
 366     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SEED);
 367     if (p != NULL && !kbkdf_set_buffer(&ctx->iv, &ctx->iv_len, p))
 368         return 0;
 369
 370     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KBKDF_USE_L);
 371     if (p != NULL && !OSSL_PARAM_get_int(p, &ctx->use_l))
 372         return 0;
 373
 374     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KBKDF_R);
 375     if (p != NULL) {
 376         int new_r = 0;
 377
 378         if (!OSSL_PARAM_get_int(p, &new_r))
 379             return 0;
 380         if (new_r != 8 && new_r != 16 && new_r != 24 && new_r != 32)
 381             return 0;
 382         ctx->r = new_r;
 383     }
 384
 385     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KBKDF_USE_SEPARATOR);
 386     if (p != NULL && !OSSL_PARAM_get_int(p, &ctx->use_separator))
 387         return 0;
 388
 389     /* Set up digest context, if we can. */
 390     if (ctx->ctx_init != NULL && ctx->ki_len != 0
 391             && !EVP_MAC_init(ctx->ctx_init, ctx->ki, ctx->ki_len, NULL))
 392             return 0;
 393     return 1;
 394 }
 395
 396 static const OSSL_PARAM *kbkdf_settable_ctx_params(ossl_unused void *ctx,
 397                                                    ossl_unused void *provctx)
 398 {
 399     static const OSSL_PARAM known_settable_ctx_params[] = {
 400         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_INFO, NULL, 0),
 401         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
 402         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
 403         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SEED, NULL, 0),
 404         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
 405         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_CIPHER, NULL, 0),
 406         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_MAC, NULL, 0),
 407         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_MODE, NULL, 0),
 408         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
 409         OSSL_PARAM_int(OSSL_KDF_PARAM_KBKDF_USE_L, NULL),
 410         OSSL_PARAM_int(OSSL_KDF_PARAM_KBKDF_USE_SEPARATOR, NULL),
 411         OSSL_PARAM_int(OSSL_KDF_PARAM_KBKDF_R, NULL),
 412         OSSL_PARAM_END,
 413     };
 414     return known_settable_ctx_params;
 415 }
 416
 417 static int kbkdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
 418 {
 419     OSSL_PARAM *p;
 420
 421     p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE);
 422     if (p == NULL)
 423         return -2;
 424
 425     /* KBKDF can produce results as large as you like. */
 426     return OSSL_PARAM_set_size_t(p, SIZE_MAX);
 427 }
 428
 429 static const OSSL_PARAM *kbkdf_gettable_ctx_params(ossl_unused void *ctx,
 430                                                    ossl_unused void *provctx)
 431 {
 432     static const OSSL_PARAM known_gettable_ctx_params[] =
 433         { OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL), OSSL_PARAM_END };
 434     return known_gettable_ctx_params;
 435 }
 436
 437 const OSSL_DISPATCH ossl_kdf_kbkdf_functions[] = {
 438     { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kbkdf_new },
 439     { OSSL_FUNC_KDF_DUPCTX, (void(*)(void))kbkdf_dup },
 440     { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kbkdf_free },
 441     { OSSL_FUNC_KDF_RESET, (void(*)(void))kbkdf_reset },
 442     { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kbkdf_derive },
 443     { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
 444       (void(*)(void))kbkdf_settable_ctx_params },
 445     { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kbkdf_set_ctx_params },
 446     { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
 447       (void(*)(void))kbkdf_gettable_ctx_params },
 448     { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kbkdf_get_ctx_params },
 449     { 0, NULL },
 450 };