providers/implementations/kdfs/x942kdf.c

   1 /*
   2  * Copyright 2019 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
  13 #ifndef OPENSSL_NO_CMS
  14
  15 # include <stdlib.h>
  16 # include <stdarg.h>
  17 # include <string.h>
  18 # include <openssl/hmac.h>
  19 # include <openssl/cms.h>
  20 # include <openssl/evp.h>
  21 # include <openssl/kdf.h>
  22 # include <openssl/x509.h>
  23 # include <openssl/obj_mac.h>
  24 # include <openssl/core_names.h>
  25 # include "internal/cryptlib.h"
  26 # include "internal/numbers.h"
  27 # include "crypto/evp.h"
  28 # include "prov/provider_ctx.h"
  29 # include "prov/providercommonerr.h"
  30 # include "prov/implementations.h"
  31 # include "prov/provider_util.h"
  32
  33 # define X942KDF_MAX_INLEN (1 << 30)
  34
  35 static OSSL_FUNC_kdf_newctx_fn x942kdf_new;
  36 static OSSL_FUNC_kdf_freectx_fn x942kdf_free;
  37 static OSSL_FUNC_kdf_reset_fn x942kdf_reset;
  38 static OSSL_FUNC_kdf_derive_fn x942kdf_derive;
  39 static OSSL_FUNC_kdf_settable_ctx_params_fn x942kdf_settable_ctx_params;
  40 static OSSL_FUNC_kdf_set_ctx_params_fn x942kdf_set_ctx_params;
  41 static OSSL_FUNC_kdf_gettable_ctx_params_fn x942kdf_gettable_ctx_params;
  42 static OSSL_FUNC_kdf_get_ctx_params_fn x942kdf_get_ctx_params;
  43
  44 typedef struct {
  45     void *provctx;
  46     PROV_DIGEST digest;
  47     unsigned char *secret;
  48     size_t secret_len;
  49     int cek_nid;
  50     unsigned char *ukm;
  51     size_t ukm_len;
  52     size_t dkm_len;
  53 } KDF_X942;
  54
  55 /* A table of allowed wrapping algorithms and the associated output lengths */
  56 static const struct {
  57     int nid;
  58     size_t keklen; /* size in bytes */
  59 } kek_algs[] = {
  60     { NID_id_smime_alg_CMS3DESwrap, 24 },
  61     { NID_id_smime_alg_CMSRC2wrap, 16 },
  62     { NID_id_aes128_wrap, 16 },
  63     { NID_id_aes192_wrap, 24 },
  64     { NID_id_aes256_wrap, 32 },
  65     { NID_id_camellia128_wrap, 16 },
  66     { NID_id_camellia192_wrap, 24 },
  67     { NID_id_camellia256_wrap, 32 }
  68 };
  69
  70 /* Skip past an ASN1 structure: for OBJECT skip content octets too */
  71 static int skip_asn1(unsigned char **pp, long *plen, int exptag)
  72 {
  73     int i, tag, xclass;
  74     long tmplen;
  75     const unsigned char *q = *pp;
  76
  77     i = ASN1_get_object(&q, &tmplen, &tag, &xclass, *plen);
  78     if ((i & 0x80) != 0 || tag != exptag || xclass != V_ASN1_UNIVERSAL)
  79         return 0;
  80     if (tag == V_ASN1_OBJECT)
  81         q += tmplen;
  82     *pp = (unsigned char *)q;
  83     *plen -= q - *pp;
  84     return 1;
  85 }
  86
  87 /*
  88  * Encode the other info structure.
  89  *
  90  *  RFC2631 Section 2.1.2 Contains the following definition for otherinfo
  91  *
  92  *  OtherInfo ::= SEQUENCE {
  93  *      keyInfo KeySpecificInfo,
  94  *      partyAInfo [0] OCTET STRING OPTIONAL,
  95  *      suppPubInfo [2] OCTET STRING
  96  *  }
  97  *
  98  *  KeySpecificInfo ::= SEQUENCE {
  99  *      algorithm OBJECT IDENTIFIER,
 100  *      counter OCTET STRING SIZE (4..4)
 101  *  }
 102  *
 103  * |nid| is the algorithm object identifier.
 104  * |keylen| is the length (in bytes) of the generated KEK. It is stored into
 105  * suppPubInfo (in bits).
 106  * |ukm| is the optional user keying material that is stored into partyAInfo. It
 107  * can be NULL.
 108  * |ukmlen| is the user keying material length (in bytes).
 109  * |der| is the returned encoded data. It must be freed by the caller.
 110  * |der_len| is the returned size of the encoded data.
 111  * |out_ctr| returns a pointer to the counter data which is embedded inside the
 112  * encoded data. This allows the counter bytes to be updated without re-encoding.
 113  *
 114  * Returns: 1 if successfully encoded, or 0 otherwise.
 115  * Assumptions: |der|, |der_len| & |out_ctr| are not NULL.
 116  */
 117 static int x942_encode_otherinfo(int nid, size_t keylen,
 118                                  const unsigned char *ukm, size_t ukmlen,
 119                                  unsigned char **der, size_t *der_len,
 120                                  unsigned char **out_ctr)
 121 {
 122     unsigned char *p, *encoded = NULL;
 123     int ret = 0, encoded_len;
 124     long tlen;
 125     /* "magic" value to check offset is sane */
 126     static unsigned char ctr[4] = { 0x00, 0x00, 0x00, 0x01 };
 127     X509_ALGOR *ksi = NULL;
 128     ASN1_OBJECT *alg_oid = NULL;
 129     ASN1_OCTET_STRING *ctr_oct = NULL, *ukm_oct = NULL;
 130
 131     /* set the KeySpecificInfo - which contains an algorithm oid and counter */
 132     ksi = X509_ALGOR_new();
 133     alg_oid = OBJ_dup(OBJ_nid2obj(nid));
 134     ctr_oct = ASN1_OCTET_STRING_new();
 135     if (ksi == NULL
 136         || alg_oid == NULL
 137         || ctr_oct == NULL
 138         || !ASN1_OCTET_STRING_set(ctr_oct, ctr, sizeof(ctr))
 139         || !X509_ALGOR_set0(ksi, alg_oid, V_ASN1_OCTET_STRING, ctr_oct))
 140         goto err;
 141     /* NULL these as they now belong to ksi */
 142     alg_oid = NULL;
 143     ctr_oct = NULL;
 144
 145     /* Set the optional partyAInfo */
 146     if (ukm != NULL) {
 147         ukm_oct = ASN1_OCTET_STRING_new();
 148         if (ukm_oct == NULL)
 149             goto err;
 150         ASN1_OCTET_STRING_set(ukm_oct, (unsigned char *)ukm, ukmlen);
 151     }
 152     /* Generate the OtherInfo DER data */
 153     encoded_len = CMS_SharedInfo_encode(&encoded, ksi, ukm_oct, keylen);
 154     if (encoded_len <= 0)
 155         goto err;
 156
 157     /* Parse the encoded data to find the offset of the counter data */
 158     p = encoded;
 159     tlen = (long)encoded_len;
 160     if (skip_asn1(&p, &tlen, V_ASN1_SEQUENCE)
 161         && skip_asn1(&p, &tlen, V_ASN1_SEQUENCE)
 162         && skip_asn1(&p, &tlen, V_ASN1_OBJECT)
 163         && skip_asn1(&p, &tlen, V_ASN1_OCTET_STRING)
 164         && CRYPTO_memcmp(p, ctr, 4) == 0) {
 165         *out_ctr = p;
 166         *der = encoded;
 167         *der_len = (size_t)encoded_len;
 168         ret = 1;
 169     }
 170 err:
 171     if (ret != 1)
 172         OPENSSL_free(encoded);
 173     ASN1_OCTET_STRING_free(ctr_oct);
 174     ASN1_OCTET_STRING_free(ukm_oct);
 175     ASN1_OBJECT_free(alg_oid);
 176     X509_ALGOR_free(ksi);
 177     return ret;
 178 }
 179
 180 static int x942kdf_hash_kdm(const EVP_MD *kdf_md,
 181                             const unsigned char *z, size_t z_len,
 182                             const unsigned char *other, size_t other_len,
 183                             unsigned char *ctr,
 184                             unsigned char *derived_key, size_t derived_key_len)
 185 {
 186     int ret = 0, hlen;
 187     size_t counter, out_len, len = derived_key_len;
 188     unsigned char mac[EVP_MAX_MD_SIZE];
 189     unsigned char *out = derived_key;
 190     EVP_MD_CTX *ctx = NULL, *ctx_init = NULL;
 191
 192     if (z_len > X942KDF_MAX_INLEN || other_len > X942KDF_MAX_INLEN
 193             || derived_key_len > X942KDF_MAX_INLEN
 194             || derived_key_len == 0) {
 195         ERR_raise(ERR_LIB_PROV, PROV_R_BAD_LENGTH);
 196         return 0;
 197     }
 198
 199     hlen = EVP_MD_size(kdf_md);
 200     if (hlen <= 0)
 201         return 0;
 202     out_len = (size_t)hlen;
 203
 204     ctx = EVP_MD_CTX_create();
 205     ctx_init = EVP_MD_CTX_create();
 206     if (ctx == NULL || ctx_init == NULL)
 207         goto end;
 208
 209     if (!EVP_DigestInit(ctx_init, kdf_md))
 210         goto end;
 211
 212     for (counter = 1;; counter++) {
 213         /* updating the ctr modifies 4 bytes in the 'other' buffer */
 214         ctr[0] = (unsigned char)((counter >> 24) & 0xff);
 215         ctr[1] = (unsigned char)((counter >> 16) & 0xff);
 216         ctr[2] = (unsigned char)((counter >> 8) & 0xff);
 217         ctr[3] = (unsigned char)(counter & 0xff);
 218
 219         if (!EVP_MD_CTX_copy_ex(ctx, ctx_init)
 220             || !EVP_DigestUpdate(ctx, z, z_len)
 221             || !EVP_DigestUpdate(ctx, other, other_len))
 222             goto end;
 223         if (len >= out_len) {
 224             if (!EVP_DigestFinal_ex(ctx, out, NULL))
 225                 goto end;
 226             out += out_len;
 227             len -= out_len;
 228             if (len == 0)
 229                 break;
 230         } else {
 231             if (!EVP_DigestFinal_ex(ctx, mac, NULL))
 232                 goto end;
 233             memcpy(out, mac, len);
 234             break;
 235         }
 236     }
 237     ret = 1;
 238 end:
 239     EVP_MD_CTX_free(ctx);
 240     EVP_MD_CTX_free(ctx_init);
 241     OPENSSL_cleanse(mac, sizeof(mac));
 242     return ret;
 243 }
 244
 245 static void *x942kdf_new(void *provctx)
 246 {
 247     KDF_X942 *ctx;
 248
 249     if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL)
 250         ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
 251     ctx->provctx = provctx;
 252     return ctx;
 253 }
 254
 255 static void x942kdf_reset(void *vctx)
 256 {
 257     KDF_X942 *ctx = (KDF_X942 *)vctx;
 258
 259     ossl_prov_digest_reset(&ctx->digest);
 260     OPENSSL_clear_free(ctx->secret, ctx->secret_len);
 261     OPENSSL_clear_free(ctx->ukm, ctx->ukm_len);
 262     memset(ctx, 0, sizeof(*ctx));
 263 }
 264
 265 static void x942kdf_free(void *vctx)
 266 {
 267     KDF_X942 *ctx = (KDF_X942 *)vctx;
 268
 269     if (ctx != NULL) {
 270         x942kdf_reset(ctx);
 271         OPENSSL_free(ctx);
 272     }
 273 }
 274
 275 static int x942kdf_set_buffer(unsigned char **out, size_t *out_len,
 276                               const OSSL_PARAM *p)
 277 {
 278     if (p->data_size == 0 || p->data == NULL)
 279         return 1;
 280
 281     OPENSSL_free(*out);
 282     *out = NULL;
 283     return OSSL_PARAM_get_octet_string(p, (void **)out, 0, out_len);
 284 }
 285
 286 static size_t x942kdf_size(KDF_X942 *ctx)
 287 {
 288     int len;
 289     const EVP_MD *md = ossl_prov_digest_md(&ctx->digest);
 290
 291     if (md == NULL) {
 292         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
 293         return 0;
 294     }
 295     len = EVP_MD_size(md);
 296     return (len <= 0) ? 0 : (size_t)len;
 297 }
 298
 299 static int x942kdf_derive(void *vctx, unsigned char *key, size_t keylen)
 300 {
 301     KDF_X942 *ctx = (KDF_X942 *)vctx;
 302     const EVP_MD *md = ossl_prov_digest_md(&ctx->digest);
 303     int ret = 0;
 304     unsigned char *ctr;
 305     unsigned char *der = NULL;
 306     size_t der_len = 0;
 307
 308     if (ctx->secret == NULL) {
 309         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SECRET);
 310         return 0;
 311     }
 312     if (md == NULL) {
 313         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
 314         return 0;
 315     }
 316     if (ctx->cek_nid == NID_undef) {
 317         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_CEK_ALG);
 318         return 0;
 319     }
 320     if (ctx->ukm != NULL && ctx->ukm_len >= X942KDF_MAX_INLEN) {
 321         /*
 322          * Note the ukm length MUST be 512 bits.
 323          * For backwards compatibility the old check is being done.
 324          */
 325         ERR_raise(ERR_LIB_PROV, PROV_R_INAVLID_UKM_LENGTH);
 326         return 0;
 327     }
 328     if (keylen != ctx->dkm_len) {
 329         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_CEK_ALG);
 330         return 0;
 331     }
 332     /* generate the otherinfo der */
 333     if (!x942_encode_otherinfo(ctx->cek_nid, ctx->dkm_len,
 334                                ctx->ukm, ctx->ukm_len,
 335                                &der, &der_len, &ctr)) {
 336         ERR_raise(ERR_LIB_PROV, PROV_R_BAD_ENCODING);
 337         return 0;
 338     }
 339     ret = x942kdf_hash_kdm(md, ctx->secret, ctx->secret_len,
 340                            der, der_len, ctr, key, keylen);
 341     OPENSSL_free(der);
 342     return ret;
 343 }
 344
 345 static int x942kdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
 346 {
 347     const OSSL_PARAM *p;
 348     KDF_X942 *ctx = vctx;
 349     OPENSSL_CTX *provctx = PROV_LIBRARY_CONTEXT_OF(ctx->provctx);
 350     size_t i;
 351
 352     if (!ossl_prov_digest_load_from_params(&ctx->digest, params, provctx))
 353         return 0;
 354
 355     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SECRET)) != NULL
 356         || (p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY)) != NULL)
 357         if (!x942kdf_set_buffer(&ctx->secret, &ctx->secret_len, p))
 358             return 0;
 359
 360     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_UKM)) != NULL)
 361         if (!x942kdf_set_buffer(&ctx->ukm, &ctx->ukm_len, p))
 362             return 0;
 363
 364     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_CEK_ALG)) != NULL) {
 365         if (p->data_type != OSSL_PARAM_UTF8_STRING)
 366             return 0;
 367         ctx->cek_nid = OBJ_sn2nid(p->data);
 368         for (i = 0; i < OSSL_NELEM(kek_algs); i++)
 369             if (kek_algs[i].nid == ctx->cek_nid)
 370                 goto cek_found;
 371         ERR_raise(ERR_LIB_PROV, PROV_R_UNSUPPORTED_CEK_ALG);
 372         return 0;
 373 cek_found:
 374         ctx->dkm_len = kek_algs[i].keklen;
 375     }
 376     return 1;
 377 }
 378
 379 static const OSSL_PARAM *x942kdf_settable_ctx_params(void)
 380 {
 381     static const OSSL_PARAM known_settable_ctx_params[] = {
 382         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
 383         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
 384         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SECRET, NULL, 0),
 385         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
 386         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_UKM, NULL, 0),
 387         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_CEK_ALG, NULL, 0),
 388         OSSL_PARAM_END
 389     };
 390     return known_settable_ctx_params;
 391 }
 392
 393 static int x942kdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
 394 {
 395     KDF_X942 *ctx = (KDF_X942 *)vctx;
 396     OSSL_PARAM *p;
 397
 398     if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
 399         return OSSL_PARAM_set_size_t(p, x942kdf_size(ctx));
 400     return -2;
 401 }
 402
 403 static const OSSL_PARAM *x942kdf_gettable_ctx_params(void)
 404 {
 405     static const OSSL_PARAM known_gettable_ctx_params[] = {
 406         OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
 407         OSSL_PARAM_END
 408     };
 409     return known_gettable_ctx_params;
 410 }
 411
 412 const OSSL_DISPATCH kdf_x942_kdf_functions[] = {
 413     { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))x942kdf_new },
 414     { OSSL_FUNC_KDF_FREECTX, (void(*)(void))x942kdf_free },
 415     { OSSL_FUNC_KDF_RESET, (void(*)(void))x942kdf_reset },
 416     { OSSL_FUNC_KDF_DERIVE, (void(*)(void))x942kdf_derive },
 417     { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
 418       (void(*)(void))x942kdf_settable_ctx_params },
 419     { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))x942kdf_set_ctx_params },
 420     { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
 421       (void(*)(void))x942kdf_gettable_ctx_params },
 422     { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))x942kdf_get_ctx_params },
 423     { 0, NULL }
 424 };
 425
 426 #endif /* OPENSSL_NO_CMS */