providers/implementations/kdfs/x942kdf.c

   1 /*
   2  * Copyright 2019-2020 The OpenSSL Project Authors. All Rights Reserved.
   3  * Copyright (c) 2019, Oracle and/or its affiliates.  All rights reserved.
   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 #include "e_os.h"
  12 #include <openssl/core_names.h>
  13 #include <openssl/core_dispatch.h>
  14 #include <openssl/err.h>
  15 #include <openssl/evp.h>
  16 #include <openssl/params.h>
  17 #include "internal/packet.h"
  18 #include "internal/der.h"
  19 #include "prov/provider_ctx.h"
  20 #include "prov/providercommonerr.h"
  21 #include "prov/implementations.h"
  22 #include "prov/provider_util.h"
  23 #include "prov/der_wrap.h"
  24
  25 #define X942KDF_MAX_INLEN (1 << 30)
  26
  27 static OSSL_FUNC_kdf_newctx_fn x942kdf_new;
  28 static OSSL_FUNC_kdf_freectx_fn x942kdf_free;
  29 static OSSL_FUNC_kdf_reset_fn x942kdf_reset;
  30 static OSSL_FUNC_kdf_derive_fn x942kdf_derive;
  31 static OSSL_FUNC_kdf_settable_ctx_params_fn x942kdf_settable_ctx_params;
  32 static OSSL_FUNC_kdf_set_ctx_params_fn x942kdf_set_ctx_params;
  33 static OSSL_FUNC_kdf_gettable_ctx_params_fn x942kdf_gettable_ctx_params;
  34 static OSSL_FUNC_kdf_get_ctx_params_fn x942kdf_get_ctx_params;
  35
  36 typedef struct {
  37     void *provctx;
  38     PROV_DIGEST digest;
  39     unsigned char *secret;
  40     size_t secret_len;
  41     unsigned char *ukm;
  42     size_t ukm_len;
  43     size_t dkm_len;
  44     const unsigned char *cek_oid;
  45     size_t cek_oid_len;
  46 } KDF_X942;
  47
  48 /*
  49  * A table of allowed wrapping algorithms, oids and the associated output
  50  * lengths.
  51  * NOTE: RC2wrap and camellia128_wrap have been removed as there are no
  52  * corresponding ciphers for these operations.
  53  */
  54 static const struct {
  55     const char *name;
  56     const unsigned char *oid;
  57     size_t oid_len;
  58     size_t keklen; /* size in bytes */
  59 } kek_algs[] = {
  60     { "AES-128-WRAP", der_oid_id_aes128_wrap, DER_OID_SZ_id_aes128_wrap, 16 },
  61     { "AES-192-WRAP", der_oid_id_aes192_wrap, DER_OID_SZ_id_aes192_wrap, 24 },
  62     { "AES-256-WRAP", der_oid_id_aes256_wrap, DER_OID_SZ_id_aes256_wrap, 32 },
  63 #ifndef FIPS_MODULE
  64     { "DES3-WRAP", der_oid_id_alg_CMS3DESwrap, DER_OID_SZ_id_alg_CMS3DESwrap,
  65       24 },
  66 #endif
  67 };
  68
  69 static int find_alg_id(OPENSSL_CTX *libctx, const char *algname, size_t *id)
  70 {
  71     int ret = 1;
  72     size_t i;
  73     EVP_CIPHER *cipher;
  74
  75     cipher = EVP_CIPHER_fetch(libctx, algname, NULL);
  76     if (cipher != NULL) {
  77         for (i = 0; i < OSSL_NELEM(kek_algs); i++) {
  78             if (EVP_CIPHER_is_a(cipher, kek_algs[i].name)) {
  79                 *id = i;
  80                 goto end;
  81             }
  82         }
  83     }
  84     ret = 0;
  85     ERR_raise(ERR_LIB_PROV, PROV_R_UNSUPPORTED_CEK_ALG);
  86 end:
  87     EVP_CIPHER_free(cipher);
  88     return ret;
  89 }
  90
  91 static int DER_w_keyinfo(WPACKET *pkt,
  92                          const unsigned char *der_oid, size_t der_oidlen,
  93                          unsigned char **pcounter)
  94 {
  95     return DER_w_begin_sequence(pkt, -1)
  96            /* Store the initial value of 1 into the counter */
  97            && DER_w_octet_string_uint32(pkt, -1, 1)
  98            /* Remember where we stored the counter in the buffer */
  99            && (pcounter == NULL
 100                || (*pcounter = WPACKET_get_curr(pkt)) != NULL)
 101            && DER_w_precompiled(pkt, -1, der_oid, der_oidlen)
 102            && DER_w_end_sequence(pkt, -1);
 103 }
 104
 105 static int der_encode_sharedinfo(WPACKET *pkt, unsigned char *buf, size_t buflen,
 106                                  const unsigned char *der_oid, size_t der_oidlen,
 107                                  const unsigned char *ukm, size_t ukmlen,
 108                                  uint32_t keylen_bits, unsigned char **pcounter)
 109 {
 110     return (buf != NULL ? WPACKET_init_der(pkt, buf, buflen) :
 111                           WPACKET_init_null_der(pkt))
 112            && DER_w_begin_sequence(pkt, -1)
 113            && DER_w_octet_string_uint32(pkt, 2, keylen_bits)
 114            && (ukm == NULL || DER_w_octet_string(pkt, 0, ukm, ukmlen))
 115            && DER_w_keyinfo(pkt, der_oid, der_oidlen, pcounter)
 116            && DER_w_end_sequence(pkt, -1)
 117            && WPACKET_finish(pkt);
 118 }
 119
 120 /*
 121  * Encode the other info structure.
 122  *
 123  *  RFC2631 Section 2.1.2 Contains the following definition for otherinfo
 124  *
 125  *  OtherInfo ::= SEQUENCE {
 126  *      keyInfo KeySpecificInfo,
 127  *      partyAInfo [0] OCTET STRING OPTIONAL,
 128  *      suppPubInfo [2] OCTET STRING
 129  *  }
 130  *  Note suppPubInfo is the key length (in bits) (stored into 4 bytes)
 131  *
 132  *
 133  *  KeySpecificInfo ::= SEQUENCE {
 134  *      algorithm OBJECT IDENTIFIER,
 135  *      counter OCTET STRING SIZE (4..4)
 136  *  }
 137  *
 138  * |keylen| is the length (in bytes) of the generated KEK. It is stored into
 139  * suppPubInfo (in bits).
 140  * |cek_oid| The oid of the key wrapping algorithm.
 141  * |cek_oidlen| The length (in bytes) of the key wrapping algorithm oid,
 142  * |ukm| is the optional user keying material that is stored into partyAInfo. It
 143  * can be NULL.
 144  * |ukmlen| is the user keying material length (in bytes).
 145  * |der| is the returned encoded data. It must be freed by the caller.
 146  * |der_len| is the returned size of the encoded data.
 147  * |out_ctr| returns a pointer to the counter data which is embedded inside the
 148  * encoded data. This allows the counter bytes to be updated without re-encoding.
 149  *
 150  * Returns: 1 if successfully encoded, or 0 otherwise.
 151  * Assumptions: |der|, |der_len| & |out_ctr| are not NULL.
 152  */
 153 static int x942_encode_otherinfo(size_t keylen,
 154                                  const unsigned char *cek_oid, size_t cek_oidlen,
 155                                  const unsigned char *ukm, size_t ukmlen,
 156                                  unsigned char **der, size_t *der_len,
 157                                  unsigned char **out_ctr)
 158 {
 159     int ret = 0;
 160     unsigned char *pcounter = NULL, *der_buf = NULL;
 161     size_t der_buflen = 0;
 162     WPACKET pkt;
 163     uint32_t keylen_bits;
 164
 165     /* keylenbits must fit into 4 bytes */
 166     if (keylen > 0xFFFFFF)
 167         goto err;
 168     keylen_bits = 8 * keylen;
 169
 170     /* Calculate the size of the buffer */
 171     if (!der_encode_sharedinfo(&pkt, NULL, 0, cek_oid, cek_oidlen, ukm, ukmlen,
 172                                keylen_bits, NULL)
 173         || !WPACKET_get_total_written(&pkt, &der_buflen))
 174         goto err;
 175     WPACKET_cleanup(&pkt);
 176     /* Alloc the buffer */
 177     der_buf = OPENSSL_zalloc(der_buflen);
 178     if (der_buf == NULL)
 179         goto err;
 180     /* Encode into the buffer */
 181     if (!der_encode_sharedinfo(&pkt, der_buf, der_buflen, cek_oid, cek_oidlen,
 182                                ukm, ukmlen, keylen_bits, &pcounter))
 183         goto err;
 184     /*
 185      * Since we allocated the exact size required, the buffer should point to the
 186      * start of the alllocated buffer at this point.
 187      */
 188     if (WPACKET_get_curr(&pkt) != der_buf)
 189         goto err;
 190
 191     /*
 192      * The data for the DER encoded octet string of a 32 bit counter = 1
 193      * should be 04 04 00 00 00 01
 194      * So just check the header is correct and skip over it.
 195      * This counter will be incremented in the kdf update loop.
 196      */
 197     if (pcounter == NULL
 198         || pcounter[0] != 0x04
 199         || pcounter[1] != 0x04)
 200         goto err;
 201     *out_ctr = (pcounter + 2);
 202     *der = der_buf;
 203     *der_len = der_buflen;
 204     ret = 1;
 205 err:
 206     WPACKET_cleanup(&pkt);
 207     return ret;
 208 }
 209
 210 static int x942kdf_hash_kdm(const EVP_MD *kdf_md,
 211                             const unsigned char *z, size_t z_len,
 212                             const unsigned char *other, size_t other_len,
 213                             unsigned char *ctr,
 214                             unsigned char *derived_key, size_t derived_key_len)
 215 {
 216     int ret = 0, hlen;
 217     size_t counter, out_len, len = derived_key_len;
 218     unsigned char mac[EVP_MAX_MD_SIZE];
 219     unsigned char *out = derived_key;
 220     EVP_MD_CTX *ctx = NULL, *ctx_init = NULL;
 221
 222     if (z_len > X942KDF_MAX_INLEN || other_len > X942KDF_MAX_INLEN
 223             || derived_key_len > X942KDF_MAX_INLEN
 224             || derived_key_len == 0) {
 225         ERR_raise(ERR_LIB_PROV, PROV_R_BAD_LENGTH);
 226         return 0;
 227     }
 228
 229     hlen = EVP_MD_size(kdf_md);
 230     if (hlen <= 0)
 231         return 0;
 232     out_len = (size_t)hlen;
 233
 234     ctx = EVP_MD_CTX_create();
 235     ctx_init = EVP_MD_CTX_create();
 236     if (ctx == NULL || ctx_init == NULL)
 237         goto end;
 238
 239     if (!EVP_DigestInit(ctx_init, kdf_md))
 240         goto end;
 241
 242     for (counter = 1;; counter++) {
 243         /* updating the ctr modifies 4 bytes in the 'other' buffer */
 244         ctr[0] = (unsigned char)((counter >> 24) & 0xff);
 245         ctr[1] = (unsigned char)((counter >> 16) & 0xff);
 246         ctr[2] = (unsigned char)((counter >> 8) & 0xff);
 247         ctr[3] = (unsigned char)(counter & 0xff);
 248
 249         if (!EVP_MD_CTX_copy_ex(ctx, ctx_init)
 250             || !EVP_DigestUpdate(ctx, z, z_len)
 251             || !EVP_DigestUpdate(ctx, other, other_len))
 252             goto end;
 253         if (len >= out_len) {
 254             if (!EVP_DigestFinal_ex(ctx, out, NULL))
 255                 goto end;
 256             out += out_len;
 257             len -= out_len;
 258             if (len == 0)
 259                 break;
 260         } else {
 261             if (!EVP_DigestFinal_ex(ctx, mac, NULL))
 262                 goto end;
 263             memcpy(out, mac, len);
 264             break;
 265         }
 266     }
 267     ret = 1;
 268 end:
 269     EVP_MD_CTX_free(ctx);
 270     EVP_MD_CTX_free(ctx_init);
 271     OPENSSL_cleanse(mac, sizeof(mac));
 272     return ret;
 273 }
 274
 275 static void *x942kdf_new(void *provctx)
 276 {
 277     KDF_X942 *ctx;
 278
 279     if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL)
 280         ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
 281     ctx->provctx = provctx;
 282     return ctx;
 283 }
 284
 285 static void x942kdf_reset(void *vctx)
 286 {
 287     KDF_X942 *ctx = (KDF_X942 *)vctx;
 288     void *provctx = ctx->provctx;
 289
 290     ossl_prov_digest_reset(&ctx->digest);
 291     OPENSSL_clear_free(ctx->secret, ctx->secret_len);
 292     OPENSSL_clear_free(ctx->ukm, ctx->ukm_len);
 293     memset(ctx, 0, sizeof(*ctx));
 294     ctx->provctx = provctx;
 295 }
 296
 297 static void x942kdf_free(void *vctx)
 298 {
 299     KDF_X942 *ctx = (KDF_X942 *)vctx;
 300
 301     if (ctx != NULL) {
 302         x942kdf_reset(ctx);
 303         OPENSSL_free(ctx);
 304     }
 305 }
 306
 307 static int x942kdf_set_buffer(unsigned char **out, size_t *out_len,
 308                               const OSSL_PARAM *p)
 309 {
 310     if (p->data_size == 0 || p->data == NULL)
 311         return 1;
 312
 313     OPENSSL_free(*out);
 314     *out = NULL;
 315     return OSSL_PARAM_get_octet_string(p, (void **)out, 0, out_len);
 316 }
 317
 318 static size_t x942kdf_size(KDF_X942 *ctx)
 319 {
 320     int len;
 321     const EVP_MD *md = ossl_prov_digest_md(&ctx->digest);
 322
 323     if (md == NULL) {
 324         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
 325         return 0;
 326     }
 327     len = EVP_MD_size(md);
 328     return (len <= 0) ? 0 : (size_t)len;
 329 }
 330
 331 static int x942kdf_derive(void *vctx, unsigned char *key, size_t keylen)
 332 {
 333     KDF_X942 *ctx = (KDF_X942 *)vctx;
 334     const EVP_MD *md = ossl_prov_digest_md(&ctx->digest);
 335     int ret = 0;
 336     unsigned char *ctr;
 337     unsigned char *der = NULL;
 338     size_t der_len = 0;
 339
 340     if (ctx->secret == NULL) {
 341         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SECRET);
 342         return 0;
 343     }
 344     if (md == NULL) {
 345         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
 346         return 0;
 347     }
 348     if (ctx->cek_oid == NULL || ctx->cek_oid_len == 0) {
 349         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_CEK_ALG);
 350         return 0;
 351     }
 352     if (ctx->ukm != NULL && ctx->ukm_len >= X942KDF_MAX_INLEN) {
 353         /*
 354          * Note the ukm length MUST be 512 bits.
 355          * For backwards compatibility the old check is being done.
 356          */
 357         ERR_raise(ERR_LIB_PROV, PROV_R_INAVLID_UKM_LENGTH);
 358         return 0;
 359     }
 360     /* generate the otherinfo der */
 361     if (!x942_encode_otherinfo(ctx->dkm_len,
 362                                ctx->cek_oid, ctx->cek_oid_len,
 363                                ctx->ukm, ctx->ukm_len,
 364                                &der, &der_len, &ctr)) {
 365         ERR_raise(ERR_LIB_PROV, PROV_R_BAD_ENCODING);
 366         return 0;
 367     }
 368     ret = x942kdf_hash_kdm(md, ctx->secret, ctx->secret_len,
 369                            der, der_len, ctr, key, keylen);
 370     OPENSSL_free(der);
 371     return ret;
 372 }
 373
 374 static int x942kdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
 375 {
 376     const OSSL_PARAM *p;
 377     KDF_X942 *ctx = vctx;
 378     OPENSSL_CTX *provctx = PROV_LIBRARY_CONTEXT_OF(ctx->provctx);
 379     size_t id;
 380
 381     if (!ossl_prov_digest_load_from_params(&ctx->digest, params, provctx))
 382         return 0;
 383
 384     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SECRET)) != NULL
 385         || (p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY)) != NULL)
 386         if (!x942kdf_set_buffer(&ctx->secret, &ctx->secret_len, p))
 387             return 0;
 388
 389     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_UKM)) != NULL)
 390         if (!x942kdf_set_buffer(&ctx->ukm, &ctx->ukm_len, p))
 391             return 0;
 392
 393     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_CEK_ALG)) != NULL) {
 394         if (p->data_type != OSSL_PARAM_UTF8_STRING)
 395             return 0;
 396         if (find_alg_id(provctx, p->data, &id) == 0)
 397             return 0;
 398         ctx->cek_oid = kek_algs[id].oid;
 399         ctx->cek_oid_len = kek_algs[id].oid_len;
 400         ctx->dkm_len = kek_algs[id].keklen;
 401     }
 402     return 1;
 403 }
 404
 405 static const OSSL_PARAM *x942kdf_settable_ctx_params(void)
 406 {
 407     static const OSSL_PARAM known_settable_ctx_params[] = {
 408         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
 409         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
 410         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SECRET, NULL, 0),
 411         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
 412         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_UKM, NULL, 0),
 413         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_CEK_ALG, NULL, 0),
 414         OSSL_PARAM_END
 415     };
 416     return known_settable_ctx_params;
 417 }
 418
 419 static int x942kdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
 420 {
 421     KDF_X942 *ctx = (KDF_X942 *)vctx;
 422     OSSL_PARAM *p;
 423
 424     if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
 425         return OSSL_PARAM_set_size_t(p, x942kdf_size(ctx));
 426     return -2;
 427 }
 428
 429 static const OSSL_PARAM *x942kdf_gettable_ctx_params(void)
 430 {
 431     static const OSSL_PARAM known_gettable_ctx_params[] = {
 432         OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
 433         OSSL_PARAM_END
 434     };
 435     return known_gettable_ctx_params;
 436 }
 437
 438 const OSSL_DISPATCH kdf_x942_kdf_functions[] = {
 439     { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))x942kdf_new },
 440     { OSSL_FUNC_KDF_FREECTX, (void(*)(void))x942kdf_free },
 441     { OSSL_FUNC_KDF_RESET, (void(*)(void))x942kdf_reset },
 442     { OSSL_FUNC_KDF_DERIVE, (void(*)(void))x942kdf_derive },
 443     { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
 444       (void(*)(void))x942kdf_settable_ctx_params },
 445     { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))x942kdf_set_ctx_params },
 446     { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
 447       (void(*)(void))x942kdf_gettable_ctx_params },
 448     { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))x942kdf_get_ctx_params },
 449     { 0, NULL }
 450 };