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 "e_os.h"
  48
  49 #define 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     unsigned char *ki;
  64     size_t ki_len;
  65     unsigned char *label;
  66     size_t label_len;
  67     unsigned char *context;
  68     size_t context_len;
  69     unsigned char *iv;
  70     size_t iv_len;
  71     int use_l;
  72     int use_separator;
  73 } KBKDF;
  74
  75 /* Definitions needed for typechecking. */
  76 static OSSL_FUNC_kdf_newctx_fn kbkdf_new;
  77 static OSSL_FUNC_kdf_freectx_fn kbkdf_free;
  78 static OSSL_FUNC_kdf_reset_fn kbkdf_reset;
  79 static OSSL_FUNC_kdf_derive_fn kbkdf_derive;
  80 static OSSL_FUNC_kdf_settable_ctx_params_fn kbkdf_settable_ctx_params;
  81 static OSSL_FUNC_kdf_set_ctx_params_fn kbkdf_set_ctx_params;
  82 static OSSL_FUNC_kdf_gettable_ctx_params_fn kbkdf_gettable_ctx_params;
  83 static OSSL_FUNC_kdf_get_ctx_params_fn kbkdf_get_ctx_params;
  84
  85 /* Not all platforms have htobe32(). */
  86 static uint32_t be32(uint32_t host)
  87 {
  88     uint32_t big = 0;
  89     DECLARE_IS_ENDIAN;
  90
  91     if (!IS_LITTLE_ENDIAN)
  92         return host;
  93
  94     big |= (host & 0xff000000) >> 24;
  95     big |= (host & 0x00ff0000) >> 8;
  96     big |= (host & 0x0000ff00) << 8;
  97     big |= (host & 0x000000ff) << 24;
  98     return big;
  99 }
 100
 101 static void init(KBKDF *ctx)
 102 {
 103     ctx->use_l = 1;
 104     ctx->use_separator = 1;
 105 }
 106
 107 static void *kbkdf_new(void *provctx)
 108 {
 109     KBKDF *ctx;
 110
 111     if (!ossl_prov_is_running())
 112         return NULL;
 113
 114     ctx = OPENSSL_zalloc(sizeof(*ctx));
 115     if (ctx == NULL) {
 116         ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
 117         return NULL;
 118     }
 119
 120     ctx->provctx = provctx;
 121     init(ctx);
 122     return ctx;
 123 }
 124
 125 static void kbkdf_free(void *vctx)
 126 {
 127     KBKDF *ctx = (KBKDF *)vctx;
 128
 129     if (ctx != NULL) {
 130         kbkdf_reset(ctx);
 131         OPENSSL_free(ctx);
 132     }
 133 }
 134
 135 static void kbkdf_reset(void *vctx)
 136 {
 137     KBKDF *ctx = (KBKDF *)vctx;
 138     void *provctx = ctx->provctx;
 139
 140     EVP_MAC_CTX_free(ctx->ctx_init);
 141     OPENSSL_clear_free(ctx->context, ctx->context_len);
 142     OPENSSL_clear_free(ctx->label, ctx->label_len);
 143     OPENSSL_clear_free(ctx->ki, ctx->ki_len);
 144     OPENSSL_clear_free(ctx->iv, ctx->iv_len);
 145     memset(ctx, 0, sizeof(*ctx));
 146     ctx->provctx = provctx;
 147     init(ctx);
 148 }
 149
 150 /* SP800-108 section 5.1 or section 5.2 depending on mode. */
 151 static int derive(EVP_MAC_CTX *ctx_init, kbkdf_mode mode, unsigned char *iv,
 152                   size_t iv_len, unsigned char *label, size_t label_len,
 153                   unsigned char *context, size_t context_len,
 154                   unsigned char *k_i, size_t h, uint32_t l, int has_separator,
 155                   unsigned char *ko, size_t ko_len)
 156 {
 157     int ret = 0;
 158     EVP_MAC_CTX *ctx = NULL;
 159     size_t written = 0, to_write, k_i_len = iv_len;
 160     const unsigned char zero = 0;
 161     uint32_t counter, i;
 162     /*
 163      * From SP800-108:
 164      * The fixed input data is a concatenation of a Label,
 165      * a separation indicator 0x00, the Context, and L.
 166      * One or more of these fixed input data fields may be omitted.
 167      *
 168      * has_separator == 0 means that the separator is omitted.
 169      * Passing a value of l == 0 means that L is omitted.
 170      * The Context and L are omitted automatically if a NULL buffer is passed.
 171      */
 172     int has_l = (l != 0);
 173
 174     /* Setup K(0) for feedback mode. */
 175     if (iv_len > 0)
 176         memcpy(k_i, iv, iv_len);
 177
 178     for (counter = 1; written < ko_len; counter++) {
 179         i = be32(counter);
 180
 181         ctx = EVP_MAC_CTX_dup(ctx_init);
 182         if (ctx == NULL)
 183             goto done;
 184
 185         /* Perform feedback, if appropriate. */
 186         if (mode == FEEDBACK && !EVP_MAC_update(ctx, k_i, k_i_len))
 187             goto done;
 188
 189         if (!EVP_MAC_update(ctx, (unsigned char *)&i, 4)
 190             || !EVP_MAC_update(ctx, label, label_len)
 191             || (has_separator && !EVP_MAC_update(ctx, &zero, 1))
 192             || !EVP_MAC_update(ctx, context, context_len)
 193             || (has_l && !EVP_MAC_update(ctx, (unsigned char *)&l, 4))
 194             || !EVP_MAC_final(ctx, k_i, NULL, h))
 195             goto done;
 196
 197         to_write = ko_len - written;
 198         memcpy(ko + written, k_i, MIN(to_write, h));
 199         written += h;
 200
 201         k_i_len = h;
 202         EVP_MAC_CTX_free(ctx);
 203         ctx = NULL;
 204     }
 205
 206     ret = 1;
 207 done:
 208     EVP_MAC_CTX_free(ctx);
 209     return ret;
 210 }
 211
 212 static int kbkdf_derive(void *vctx, unsigned char *key, size_t keylen)
 213 {
 214     KBKDF *ctx = (KBKDF *)vctx;
 215     int ret = 0;
 216     unsigned char *k_i = NULL;
 217     uint32_t l = 0;
 218     size_t h = 0;
 219
 220     if (!ossl_prov_is_running())
 221         return 0;
 222
 223     /* label, context, and iv are permitted to be empty.  Check everything
 224      * else. */
 225     if (ctx->ctx_init == NULL) {
 226         if (ctx->ki_len == 0 || ctx->ki == NULL) {
 227             ERR_raise(ERR_LIB_PROV, PROV_R_NO_KEY_SET);
 228             return 0;
 229         }
 230         /* Could either be missing MAC or missing message digest or missing
 231          * cipher - arbitrarily, I pick this one. */
 232         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MAC);
 233         return 0;
 234     }
 235
 236     /* Fail if the output length is zero */
 237     if (keylen == 0) {
 238         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
 239         return 0;
 240     }
 241
 242     h = EVP_MAC_CTX_get_mac_size(ctx->ctx_init);
 243     if (h == 0)
 244         goto done;
 245     if (ctx->iv_len != 0 && ctx->iv_len != h) {
 246         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_SEED_LENGTH);
 247         goto done;
 248     }
 249
 250     if (ctx->use_l != 0)
 251         l = be32(keylen * 8);
 252
 253     k_i = OPENSSL_zalloc(h);
 254     if (k_i == NULL)
 255         goto done;
 256
 257     ret = derive(ctx->ctx_init, ctx->mode, ctx->iv, ctx->iv_len, ctx->label,
 258                  ctx->label_len, ctx->context, ctx->context_len, k_i, h, l,
 259                  ctx->use_separator, key, keylen);
 260 done:
 261     if (ret != 1)
 262         OPENSSL_cleanse(key, keylen);
 263     OPENSSL_clear_free(k_i, h);
 264     return ret;
 265 }
 266
 267 static int kbkdf_set_buffer(unsigned char **out, size_t *out_len,
 268                             const OSSL_PARAM *p)
 269 {
 270     if (p->data == NULL || p->data_size == 0)
 271         return 1;
 272
 273     OPENSSL_clear_free(*out, *out_len);
 274     *out = NULL;
 275     return OSSL_PARAM_get_octet_string(p, (void **)out, 0, out_len);
 276 }
 277
 278 static int kbkdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
 279 {
 280     KBKDF *ctx = (KBKDF *)vctx;
 281     OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx);
 282     const OSSL_PARAM *p;
 283     OSSL_PARAM mparams[2];
 284
 285     if (!ossl_prov_macctx_load_from_params(&ctx->ctx_init, params, NULL,
 286                                            NULL, NULL, libctx))
 287         return 0;
 288     else if (ctx->ctx_init != NULL
 289              && !EVP_MAC_is_a(EVP_MAC_CTX_mac(ctx->ctx_init),
 290                               OSSL_MAC_NAME_HMAC)
 291              && !EVP_MAC_is_a(EVP_MAC_CTX_mac(ctx->ctx_init),
 292                               OSSL_MAC_NAME_CMAC)) {
 293         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_MAC);
 294         return 0;
 295     }
 296
 297     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_MODE);
 298     if (p != NULL && strncasecmp("counter", p->data, p->data_size) == 0) {
 299         ctx->mode = COUNTER;
 300     } else if (p != NULL
 301                && strncasecmp("feedback", p->data, p->data_size) == 0) {
 302         ctx->mode = FEEDBACK;
 303     } else if (p != NULL) {
 304         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_MODE);
 305         return 0;
 306     }
 307
 308     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY);
 309     if (p != NULL && !kbkdf_set_buffer(&ctx->ki, &ctx->ki_len, p))
 310         return 0;
 311
 312     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT);
 313     if (p != NULL && !kbkdf_set_buffer(&ctx->label, &ctx->label_len, p))
 314         return 0;
 315
 316     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_INFO);
 317     if (p != NULL && !kbkdf_set_buffer(&ctx->context, &ctx->context_len, p))
 318         return 0;
 319
 320     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SEED);
 321     if (p != NULL && !kbkdf_set_buffer(&ctx->iv, &ctx->iv_len, p))
 322         return 0;
 323
 324     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KBKDF_USE_L);
 325     if (p != NULL && !OSSL_PARAM_get_int(p, &ctx->use_l))
 326         return 0;
 327
 328     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KBKDF_USE_SEPARATOR);
 329     if (p != NULL && !OSSL_PARAM_get_int(p, &ctx->use_separator))
 330         return 0;
 331
 332     /* Set up digest context, if we can. */
 333     if (ctx->ctx_init != NULL && ctx->ki_len != 0) {
 334         mparams[0] = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
 335                                                        ctx->ki, ctx->ki_len);
 336         mparams[1] = OSSL_PARAM_construct_end();
 337
 338         if (!EVP_MAC_CTX_set_params(ctx->ctx_init, mparams)
 339             || !EVP_MAC_init(ctx->ctx_init))
 340             return 0;
 341     }
 342
 343     return 1;
 344 }
 345
 346 static const OSSL_PARAM *kbkdf_settable_ctx_params(ossl_unused void *provctx)
 347 {
 348     static const OSSL_PARAM known_settable_ctx_params[] = {
 349         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_INFO, NULL, 0),
 350         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
 351         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
 352         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SEED, NULL, 0),
 353         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
 354         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_CIPHER, NULL, 0),
 355         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_MAC, NULL, 0),
 356         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_MODE, NULL, 0),
 357         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
 358         OSSL_PARAM_int(OSSL_KDF_PARAM_KBKDF_USE_L, NULL),
 359         OSSL_PARAM_int(OSSL_KDF_PARAM_KBKDF_USE_SEPARATOR, NULL),
 360         OSSL_PARAM_END,
 361     };
 362     return known_settable_ctx_params;
 363 }
 364
 365 static int kbkdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
 366 {
 367     OSSL_PARAM *p;
 368
 369     p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE);
 370     if (p == NULL)
 371         return -2;
 372
 373     /* KBKDF can produce results as large as you like. */
 374     return OSSL_PARAM_set_size_t(p, SIZE_MAX);
 375 }
 376
 377 static const OSSL_PARAM *kbkdf_gettable_ctx_params(ossl_unused void *provctx)
 378 {
 379     static const OSSL_PARAM known_gettable_ctx_params[] =
 380         { OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL), OSSL_PARAM_END };
 381     return known_gettable_ctx_params;
 382 }
 383
 384 const OSSL_DISPATCH ossl_kdf_kbkdf_functions[] = {
 385     { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kbkdf_new },
 386     { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kbkdf_free },
 387     { OSSL_FUNC_KDF_RESET, (void(*)(void))kbkdf_reset },
 388     { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kbkdf_derive },
 389     { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
 390       (void(*)(void))kbkdf_settable_ctx_params },
 391     { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kbkdf_set_ctx_params },
 392     { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
 393       (void(*)(void))kbkdf_gettable_ctx_params },
 394     { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kbkdf_get_ctx_params },
 395     { 0, NULL },
 396 };