providers/common/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 "internal/cryptlib.h"
  25 # include "internal/evp_int.h"
  26 # include "kdf_local.h"
  27
  28 # define X942KDF_MAX_INLEN (1 << 30)
  29
  30 struct evp_kdf_impl_st {
  31     const EVP_MD *md;
  32     unsigned char *secret;
  33     size_t secret_len;
  34     int cek_nid;
  35     unsigned char *ukm;
  36     size_t ukm_len;
  37     size_t dkm_len;
  38 };
  39
  40 /* A table of allowed wrapping algorithms and the associated output lengths */
  41 static const struct {
  42     int nid;
  43     size_t keklen; /* size in bytes */
  44 } kek_algs[] = {
  45     { NID_id_smime_alg_CMS3DESwrap, 24 },
  46     { NID_id_smime_alg_CMSRC2wrap, 16 },
  47     { NID_id_aes128_wrap, 16 },
  48     { NID_id_aes192_wrap, 24 },
  49     { NID_id_aes256_wrap, 32 },
  50     { NID_id_camellia128_wrap, 16 },
  51     { NID_id_camellia192_wrap, 24 },
  52     { NID_id_camellia256_wrap, 32 }
  53 };
  54
  55 /* Skip past an ASN1 structure: for OBJECT skip content octets too */
  56 static int skip_asn1(unsigned char **pp, long *plen, int exptag)
  57 {
  58     int i, tag, xclass;
  59     long tmplen;
  60     const unsigned char *q = *pp;
  61
  62     i = ASN1_get_object(&q, &tmplen, &tag, &xclass, *plen);
  63     if ((i & 0x80) != 0 || tag != exptag || xclass != V_ASN1_UNIVERSAL)
  64         return 0;
  65     if (tag == V_ASN1_OBJECT)
  66         q += tmplen;
  67     *pp = (unsigned char *)q;
  68     *plen -= q - *pp;
  69     return 1;
  70 }
  71
  72 /*
  73  * Encode the other info structure.
  74  *
  75  *  RFC2631 Section 2.1.2 Contains the following definition for otherinfo
  76  *
  77  *  OtherInfo ::= SEQUENCE {
  78  *      keyInfo KeySpecificInfo,
  79  *      partyAInfo [0] OCTET STRING OPTIONAL,
  80  *      suppPubInfo [2] OCTET STRING
  81  *  }
  82  *
  83  *  KeySpecificInfo ::= SEQUENCE {
  84  *      algorithm OBJECT IDENTIFIER,
  85  *      counter OCTET STRING SIZE (4..4)
  86  *  }
  87  *
  88  * |nid| is the algorithm object identifier.
  89  * |keylen| is the length (in bytes) of the generated KEK. It is stored into
  90  * suppPubInfo (in bits).
  91  * |ukm| is the optional user keying material that is stored into partyAInfo. It
  92  * can be NULL.
  93  * |ukmlen| is the user keying material length (in bytes).
  94  * |der| is the returned encoded data. It must be freed by the caller.
  95  * |der_len| is the returned size of the encoded data.
  96  * |out_ctr| returns a pointer to the counter data which is embedded inside the
  97  * encoded data. This allows the counter bytes to be updated without re-encoding.
  98  *
  99  * Returns: 1 if successfully encoded, or 0 otherwise.
 100  * Assumptions: |der|, |der_len| & |out_ctr| are not NULL.
 101  */
 102 static int x942_encode_otherinfo(int nid, size_t keylen,
 103                                  const unsigned char *ukm, size_t ukmlen,
 104                                  unsigned char **der, size_t *der_len,
 105                                  unsigned char **out_ctr)
 106 {
 107     unsigned char *p, *encoded = NULL;
 108     int ret = 0, encoded_len;
 109     long tlen;
 110     /* "magic" value to check offset is sane */
 111     static unsigned char ctr[4] = { 0x00, 0x00, 0x00, 0x01 };
 112     X509_ALGOR *ksi = NULL;
 113     ASN1_OBJECT *alg_oid = NULL;
 114     ASN1_OCTET_STRING *ctr_oct = NULL, *ukm_oct = NULL;
 115
 116     /* set the KeySpecificInfo - which contains an algorithm oid and counter */
 117     ksi = X509_ALGOR_new();
 118     alg_oid = OBJ_dup(OBJ_nid2obj(nid));
 119     ctr_oct = ASN1_OCTET_STRING_new();
 120     if (ksi == NULL
 121         || alg_oid == NULL
 122         || ctr_oct == NULL
 123         || !ASN1_OCTET_STRING_set(ctr_oct, ctr, sizeof(ctr))
 124         || !X509_ALGOR_set0(ksi, alg_oid, V_ASN1_OCTET_STRING, ctr_oct))
 125         goto err;
 126     /* NULL these as they now belong to ksi */
 127     alg_oid = NULL;
 128     ctr_oct = NULL;
 129
 130     /* Set the optional partyAInfo */
 131     if (ukm != NULL) {
 132         ukm_oct = ASN1_OCTET_STRING_new();
 133         if (ukm_oct == NULL)
 134             goto err;
 135         ASN1_OCTET_STRING_set(ukm_oct, (unsigned char *)ukm, ukmlen);
 136     }
 137     /* Generate the OtherInfo DER data */
 138     encoded_len = CMS_SharedInfo_encode(&encoded, ksi, ukm_oct, keylen);
 139     if (encoded_len <= 0)
 140         goto err;
 141
 142     /* Parse the encoded data to find the offset of the counter data */
 143     p = encoded;
 144     tlen = (long)encoded_len;
 145     if (skip_asn1(&p, &tlen, V_ASN1_SEQUENCE)
 146         && skip_asn1(&p, &tlen, V_ASN1_SEQUENCE)
 147         && skip_asn1(&p, &tlen, V_ASN1_OBJECT)
 148         && skip_asn1(&p, &tlen, V_ASN1_OCTET_STRING)
 149         && CRYPTO_memcmp(p, ctr, 4) == 0) {
 150         *out_ctr = p;
 151         *der = encoded;
 152         *der_len = (size_t)encoded_len;
 153         ret = 1;
 154     }
 155 err:
 156     if (ret != 1)
 157         OPENSSL_free(encoded);
 158     ASN1_OCTET_STRING_free(ctr_oct);
 159     ASN1_OCTET_STRING_free(ukm_oct);
 160     ASN1_OBJECT_free(alg_oid);
 161     X509_ALGOR_free(ksi);
 162     return ret;
 163 }
 164
 165 static int x942kdf_hash_kdm(const EVP_MD *kdf_md,
 166                             const unsigned char *z, size_t z_len,
 167                             const unsigned char *other, size_t other_len,
 168                             unsigned char *ctr,
 169                             unsigned char *derived_key, size_t derived_key_len)
 170 {
 171     int ret = 0, hlen;
 172     size_t counter, out_len, len = derived_key_len;
 173     unsigned char mac[EVP_MAX_MD_SIZE];
 174     unsigned char *out = derived_key;
 175     EVP_MD_CTX *ctx = NULL, *ctx_init = NULL;
 176
 177     if (z_len > X942KDF_MAX_INLEN || other_len > X942KDF_MAX_INLEN
 178             || derived_key_len > X942KDF_MAX_INLEN
 179             || derived_key_len == 0) {
 180         KDFerr(KDF_F_X942KDF_HASH_KDM, KDF_R_BAD_LENGTH);
 181         return 0;
 182     }
 183
 184     hlen = EVP_MD_size(kdf_md);
 185     if (hlen <= 0)
 186         return 0;
 187     out_len = (size_t)hlen;
 188
 189     ctx = EVP_MD_CTX_create();
 190     ctx_init = EVP_MD_CTX_create();
 191     if (ctx == NULL || ctx_init == NULL)
 192         goto end;
 193
 194     if (!EVP_DigestInit(ctx_init, kdf_md))
 195         goto end;
 196
 197     for (counter = 1;; counter++) {
 198         /* updating the ctr modifies 4 bytes in the 'other' buffer */
 199         ctr[0] = (unsigned char)((counter >> 24) & 0xff);
 200         ctr[1] = (unsigned char)((counter >> 16) & 0xff);
 201         ctr[2] = (unsigned char)((counter >> 8) & 0xff);
 202         ctr[3] = (unsigned char)(counter & 0xff);
 203
 204         if (!EVP_MD_CTX_copy_ex(ctx, ctx_init)
 205             || !EVP_DigestUpdate(ctx, z, z_len)
 206             || !EVP_DigestUpdate(ctx, other, other_len))
 207             goto end;
 208         if (len >= out_len) {
 209             if (!EVP_DigestFinal_ex(ctx, out, NULL))
 210                 goto end;
 211             out += out_len;
 212             len -= out_len;
 213             if (len == 0)
 214                 break;
 215         } else {
 216             if (!EVP_DigestFinal_ex(ctx, mac, NULL))
 217                 goto end;
 218             memcpy(out, mac, len);
 219             break;
 220         }
 221     }
 222     ret = 1;
 223 end:
 224     EVP_MD_CTX_free(ctx);
 225     EVP_MD_CTX_free(ctx_init);
 226     OPENSSL_cleanse(mac, sizeof(mac));
 227     return ret;
 228 }
 229
 230 static EVP_KDF_IMPL *x942kdf_new(void)
 231 {
 232     EVP_KDF_IMPL *impl;
 233
 234     if ((impl = OPENSSL_zalloc(sizeof(*impl))) == NULL)
 235         KDFerr(KDF_F_X942KDF_NEW, ERR_R_MALLOC_FAILURE);
 236     return impl;
 237 }
 238
 239 static void x942kdf_reset(EVP_KDF_IMPL *impl)
 240 {
 241     OPENSSL_clear_free(impl->secret, impl->secret_len);
 242     OPENSSL_clear_free(impl->ukm, impl->ukm_len);
 243     memset(impl, 0, sizeof(*impl));
 244 }
 245
 246 static void x942kdf_free(EVP_KDF_IMPL *impl)
 247 {
 248     x942kdf_reset(impl);
 249     OPENSSL_free(impl);
 250 }
 251
 252 static int x942kdf_set_buffer(va_list args, unsigned char **out, size_t *out_len)
 253 {
 254     const unsigned char *p;
 255     size_t len;
 256
 257     p = va_arg(args, const unsigned char *);
 258     len = va_arg(args, size_t);
 259     if (len == 0 || p == NULL)
 260         return 1;
 261
 262     OPENSSL_free(*out);
 263     *out = OPENSSL_memdup(p, len);
 264     if (*out == NULL)
 265         return 0;
 266
 267     *out_len = len;
 268     return 1;
 269 }
 270
 271 static int x942kdf_ctrl(EVP_KDF_IMPL *impl, int cmd, va_list args)
 272 {
 273     const EVP_MD *md;
 274     char *alg_str = NULL;
 275     size_t i;
 276
 277     switch (cmd) {
 278     case EVP_KDF_CTRL_SET_MD:
 279         md = va_arg(args, const EVP_MD *);
 280         if (md == NULL)
 281             return 0;
 282
 283         impl->md = md;
 284         return 1;
 285
 286     case EVP_KDF_CTRL_SET_KEY:
 287         return x942kdf_set_buffer(args, &impl->secret, &impl->secret_len);
 288
 289     case EVP_KDF_CTRL_SET_UKM:
 290         return x942kdf_set_buffer(args, &impl->ukm, &impl->ukm_len);
 291
 292     case EVP_KDF_CTRL_SET_CEK_ALG:
 293         alg_str = va_arg(args, char *);
 294         if (alg_str == NULL)
 295             return 0;
 296         impl->cek_nid = OBJ_sn2nid(alg_str);
 297         for (i = 0; i < (size_t)OSSL_NELEM(kek_algs); ++i) {
 298             if (kek_algs[i].nid == impl->cek_nid) {
 299                 impl->dkm_len = kek_algs[i].keklen;
 300                 return 1;
 301             }
 302         }
 303         KDFerr(KDF_F_X942KDF_CTRL, KDF_R_UNSUPPORTED_CEK_ALG);
 304         return 0;
 305
 306     default:
 307         return -2;
 308     }
 309 }
 310
 311 static int x942kdf_ctrl_str(EVP_KDF_IMPL *impl, const char *type,
 312                             const char *value)
 313 {
 314     if (strcmp(type, "digest") == 0)
 315         return kdf_md2ctrl(impl, x942kdf_ctrl, EVP_KDF_CTRL_SET_MD, value);
 316
 317     if (strcmp(type, "secret") == 0 || strcmp(type, "key") == 0)
 318          return kdf_str2ctrl(impl, x942kdf_ctrl, EVP_KDF_CTRL_SET_KEY,
 319                              value);
 320
 321     if (strcmp(type, "hexsecret") == 0 || strcmp(type, "hexkey") == 0)
 322         return kdf_hex2ctrl(impl, x942kdf_ctrl, EVP_KDF_CTRL_SET_KEY,
 323                             value);
 324
 325     if (strcmp(type, "ukm") == 0)
 326         return kdf_str2ctrl(impl, x942kdf_ctrl, EVP_KDF_CTRL_SET_UKM,
 327                             value);
 328
 329     if (strcmp(type, "hexukm") == 0)
 330         return kdf_hex2ctrl(impl, x942kdf_ctrl, EVP_KDF_CTRL_SET_UKM,
 331                             value);
 332
 333     if (strcmp(type, "cekalg") == 0)
 334         return kdf_str2ctrl(impl, x942kdf_ctrl, EVP_KDF_CTRL_SET_CEK_ALG,
 335                             value);
 336
 337     return -2;
 338 }
 339
 340 static size_t x942kdf_size(EVP_KDF_IMPL *impl)
 341 {
 342     int len;
 343
 344     if (impl->md == NULL) {
 345         KDFerr(KDF_F_X942KDF_SIZE, KDF_R_MISSING_MESSAGE_DIGEST);
 346         return 0;
 347     }
 348     len = EVP_MD_size(impl->md);
 349     return (len <= 0) ? 0 : (size_t)len;
 350 }
 351
 352 static int x942kdf_derive(EVP_KDF_IMPL *impl, unsigned char *key, size_t keylen)
 353 {
 354     int ret = 0;
 355     unsigned char *ctr;
 356     unsigned char *der = NULL;
 357     size_t der_len = 0;
 358
 359     if (impl->secret == NULL) {
 360         KDFerr(KDF_F_X942KDF_DERIVE, KDF_R_MISSING_SECRET);
 361         return 0;
 362     }
 363     if (impl->md == NULL) {
 364         KDFerr(KDF_F_X942KDF_DERIVE, KDF_R_MISSING_MESSAGE_DIGEST);
 365         return 0;
 366     }
 367     if (impl->cek_nid == NID_undef) {
 368         KDFerr(KDF_F_X942KDF_DERIVE, KDF_R_MISSING_CEK_ALG);
 369         return 0;
 370     }
 371     if (impl->ukm != NULL && impl->ukm_len >= X942KDF_MAX_INLEN) {
 372         /*
 373          * Note the ukm length MUST be 512 bits.
 374          * For backwards compatibility the old check is being done.
 375          */
 376         KDFerr(KDF_F_X942KDF_DERIVE, KDF_R_INAVLID_UKM_LEN);
 377         return 0;
 378     }
 379     if (keylen != impl->dkm_len) {
 380         KDFerr(KDF_F_X942KDF_DERIVE, KDF_R_MISSING_CEK_ALG);
 381         return 0;
 382     }
 383     /* generate the otherinfo der */
 384     if (!x942_encode_otherinfo(impl->cek_nid, impl->dkm_len,
 385                                impl->ukm, impl->ukm_len,
 386                                &der, &der_len, &ctr)) {
 387         KDFerr(KDF_F_X942KDF_DERIVE, KDF_R_BAD_ENCODING);
 388         return 0;
 389     }
 390     ret = x942kdf_hash_kdm(impl->md, impl->secret, impl->secret_len,
 391                            der, der_len, ctr, key, keylen);
 392     OPENSSL_free(der);
 393     return ret;
 394 }
 395
 396 const EVP_KDF x942_kdf_meth = {
 397     EVP_KDF_X942,
 398     x942kdf_new,
 399     x942kdf_free,
 400     x942kdf_reset,
 401     x942kdf_ctrl,
 402     x942kdf_ctrl_str,
 403     x942kdf_size,
 404     x942kdf_derive
 405 };
 406
 407 #endif /* OPENSSL_NO_CMS */