text: /*
   * Copyright 2019-2020 The OpenSSL Project Authors. All Rights Reserved.
   * Copyright (c) 2019, Oracle and/or its affiliates.  All rights reserved.
   *
   * Licensed under the Apache License 2.0 (the "License").  You may not use
   * this file except in compliance with the License.  You can obtain a copy
   * in the file LICENSE in the source distribution or at
   * https://www.openssl.org/source/license.html
   */
  
  #include "e_os.h"
  #include <openssl/core_names.h>
  #include <openssl/core_dispatch.h>
  #include <openssl/err.h>
  #include <openssl/evp.h>
  #include <openssl/params.h>
  #include "internal/packet.h"
  #include "internal/der.h"
  #include "prov/provider_ctx.h"
  #include "prov/providercommonerr.h"
  #include "prov/implementations.h"
  #include "prov/provider_util.h"
  #include "prov/der_wrap.h"
  
  #define X942KDF_MAX_INLEN (1 << 30)
  
  static OSSL_FUNC_kdf_newctx_fn x942kdf_new;
  static OSSL_FUNC_kdf_freectx_fn x942kdf_free;
  static OSSL_FUNC_kdf_reset_fn x942kdf_reset;
  static OSSL_FUNC_kdf_derive_fn x942kdf_derive;
  static OSSL_FUNC_kdf_settable_ctx_params_fn x942kdf_settable_ctx_params;
  static OSSL_FUNC_kdf_set_ctx_params_fn x942kdf_set_ctx_params;
  static OSSL_FUNC_kdf_gettable_ctx_params_fn x942kdf_gettable_ctx_params;
  static OSSL_FUNC_kdf_get_ctx_params_fn x942kdf_get_ctx_params;
  
  typedef struct {
      void *provctx;
      PROV_DIGEST digest;
      unsigned char *secret;
      size_t secret_len;
      unsigned char *ukm;
      size_t ukm_len;
      size_t dkm_len;
      const unsigned char *cek_oid;
      size_t cek_oid_len;
  } KDF_X942;
  
  /*
   * A table of allowed wrapping algorithms, oids and the associated output
   * lengths.
   * NOTE: RC2wrap and camellia128_wrap have been removed as there are no
   * corresponding ciphers for these operations.
   */
  static const struct {
      const char *name;
      const unsigned char *oid;
      size_t oid_len;
      size_t keklen; /* size in bytes */
  } kek_algs[] = {
      { "AES-128-WRAP", der_oid_id_aes128_wrap, DER_OID_SZ_id_aes128_wrap, 16 },
      { "AES-192-WRAP", der_oid_id_aes192_wrap, DER_OID_SZ_id_aes192_wrap, 24 },
      { "AES-256-WRAP", der_oid_id_aes256_wrap, DER_OID_SZ_id_aes256_wrap, 32 },
  #ifndef FIPS_MODULE
      { "DES3-WRAP", der_oid_id_alg_CMS3DESwrap, DER_OID_SZ_id_alg_CMS3DESwrap,
        24 },
  #endif
  };
  
  static int find_alg_id(OPENSSL_CTX *libctx, const char *algname, size_t *id)
  {
      int ret = 1;
      size_t i;
      EVP_CIPHER *cipher;
  
      cipher = EVP_CIPHER_fetch(libctx, algname, NULL);
      if (cipher != NULL) {
          for (i = 0; i < OSSL_NELEM(kek_algs); i++) {
              if (EVP_CIPHER_is_a(cipher, kek_algs[i].name)) {
                  *id = i;
                  goto end;
              }
          }
      }
      ret = 0;
      ERR_raise(ERR_LIB_PROV, PROV_R_UNSUPPORTED_CEK_ALG);
  end:
      EVP_CIPHER_free(cipher);
      return ret;
  }
  
  static int DER_w_keyinfo(WPACKET *pkt,
                           const unsigned char *der_oid, size_t der_oidlen,
                           unsigned char **pcounter)
  {
      return DER_w_begin_sequence(pkt, -1)
             /* Store the initial value of 1 into the counter */
             && DER_w_octet_string_uint32(pkt, -1, 1)
             /* Remember where we stored the counter in the buffer */
             && (pcounter == NULL
                 || (*pcounter = WPACKET_get_curr(pkt)) != NULL)
             && DER_w_precompiled(pkt, -1, der_oid, der_oidlen)
             && DER_w_end_sequence(pkt, -1);
  }
  
  static int der_encode_sharedinfo(WPACKET *pkt, unsigned char *buf, size_t buflen,
                                   const unsigned char *der_oid, size_t der_oidlen,
                                   const unsigned char *ukm, size_t ukmlen,
                                   uint32_t keylen_bits, unsigned char **pcounter)
  {
      return (buf != NULL ? WPACKET_init_der(pkt, buf, buflen) :
                            WPACKET_init_null_der(pkt))
             && DER_w_begin_sequence(pkt, -1)
             && DER_w_octet_string_uint32(pkt, 2, keylen_bits)
             && (ukm == NULL || DER_w_octet_string(pkt, 0, ukm, ukmlen))
             && DER_w_keyinfo(pkt, der_oid, der_oidlen, pcounter)
             && DER_w_end_sequence(pkt, -1)
             && WPACKET_finish(pkt);
  }
  
  /*
   * Encode the other info structure.
   *
   *  RFC2631 Section 2.1.2 Contains the following definition for otherinfo
   *
   *  OtherInfo ::= SEQUENCE {
   *      keyInfo KeySpecificInfo,
   *      partyAInfo [0] OCTET STRING OPTIONAL,
   *      suppPubInfo [2] OCTET STRING
   *  }
   *  Note suppPubInfo is the key length (in bits) (stored into 4 bytes)
   *
   *
   *  KeySpecificInfo ::= SEQUENCE {
   *      algorithm OBJECT IDENTIFIER,
   *      counter OCTET STRING SIZE (4..4)
   *  }
   *
   * |keylen| is the length (in bytes) of the generated KEK. It is stored into
   * suppPubInfo (in bits).
   * |cek_oid| The oid of the key wrapping algorithm.
   * |cek_oidlen| The length (in bytes) of the key wrapping algorithm oid,
   * |ukm| is the optional user keying material that is stored into partyAInfo. It
   * can be NULL.
   * |ukmlen| is the user keying material length (in bytes).
   * |der| is the returned encoded data. It must be freed by the caller.
   * |der_len| is the returned size of the encoded data.
   * |out_ctr| returns a pointer to the counter data which is embedded inside the
   * encoded data. This allows the counter bytes to be updated without re-encoding.
   *
   * Returns: 1 if successfully encoded, or 0 otherwise.
   * Assumptions: |der|, |der_len| & |out_ctr| are not NULL.
   */
  static int x942_encode_otherinfo(size_t keylen,
                                   const unsigned char *cek_oid, size_t cek_oidlen,
                                   const unsigned char *ukm, size_t ukmlen,
                                   unsigned char **der, size_t *der_len,
                                   unsigned char **out_ctr)
  {
      int ret = 0;
      unsigned char *pcounter = NULL, *der_buf = NULL;
      size_t der_buflen = 0;
      WPACKET pkt;
      uint32_t keylen_bits;
  
      /* keylenbits must fit into 4 bytes */
      if (keylen > 0xFFFFFF)
          return 0;
      keylen_bits = 8 * keylen;
  
      /* Calculate the size of the buffer */
      if (!der_encode_sharedinfo(&pkt, NULL, 0, cek_oid, cek_oidlen, ukm, ukmlen,
                                 keylen_bits, NULL)
          || !WPACKET_get_total_written(&pkt, &der_buflen))
          goto err;
      WPACKET_cleanup(&pkt);
      /* Alloc the buffer */
      der_buf = OPENSSL_zalloc(der_buflen);
      if (der_buf == NULL)
          goto err;
      /* Encode into the buffer */
      if (!der_encode_sharedinfo(&pkt, der_buf, der_buflen, cek_oid, cek_oidlen,
                                 ukm, ukmlen, keylen_bits, &pcounter))
          goto err;
      /*
       * Since we allocated the exact size required, the buffer should point to the
       * start of the alllocated buffer at this point.
       */
      if (WPACKET_get_curr(&pkt) != der_buf)
          goto err;
  
      /*
       * The data for the DER encoded octet string of a 32 bit counter = 1
       * should be 04 04 00 00 00 01
       * So just check the header is correct and skip over it.
       * This counter will be incremented in the kdf update loop.
       */
      if (pcounter == NULL
          || pcounter[0] != 0x04
          || pcounter[1] != 0x04)
          goto err;
      *out_ctr = (pcounter + 2);
      *der = der_buf;
      *der_len = der_buflen;
      ret = 1;
  err:
      WPACKET_cleanup(&pkt);
      return ret;
  }
  
  static int x942kdf_hash_kdm(const EVP_MD *kdf_md,
                              const unsigned char *z, size_t z_len,
                              const unsigned char *other, size_t other_len,
                              unsigned char *ctr,
                              unsigned char *derived_key, size_t derived_key_len)
  {
      int ret = 0, hlen;
      size_t counter, out_len, len = derived_key_len;
      unsigned char mac[EVP_MAX_MD_SIZE];
      unsigned char *out = derived_key;
      EVP_MD_CTX *ctx = NULL, *ctx_init = NULL;
  
      if (z_len > X942KDF_MAX_INLEN || other_len > X942KDF_MAX_INLEN
              || derived_key_len > X942KDF_MAX_INLEN
              || derived_key_len == 0) {
          ERR_raise(ERR_LIB_PROV, PROV_R_BAD_LENGTH);
          return 0;
      }
  
      hlen = EVP_MD_size(kdf_md);
      if (hlen <= 0)
          return 0;
      out_len = (size_t)hlen;
  
      ctx = EVP_MD_CTX_create();
      ctx_init = EVP_MD_CTX_create();
      if (ctx == NULL || ctx_init == NULL)
          goto end;
  
      if (!EVP_DigestInit(ctx_init, kdf_md))
          goto end;
  
      for (counter = 1;; counter++) {
          /* updating the ctr modifies 4 bytes in the 'other' buffer */
          ctr[0] = (unsigned char)((counter >> 24) & 0xff);
          ctr[1] = (unsigned char)((counter >> 16) & 0xff);
          ctr[2] = (unsigned char)((counter >> 8) & 0xff);
          ctr[3] = (unsigned char)(counter & 0xff);
  
          if (!EVP_MD_CTX_copy_ex(ctx, ctx_init)
              || !EVP_DigestUpdate(ctx, z, z_len)
              || !EVP_DigestUpdate(ctx, other, other_len))
              goto end;
          if (len >= out_len) {
              if (!EVP_DigestFinal_ex(ctx, out, NULL))
                  goto end;
              out += out_len;
              len -= out_len;
              if (len == 0)
                  break;
          } else {
              if (!EVP_DigestFinal_ex(ctx, mac, NULL))
                  goto end;
              memcpy(out, mac, len);
              break;
          }
      }
      ret = 1;
  end:
      EVP_MD_CTX_free(ctx);
      EVP_MD_CTX_free(ctx_init);
      OPENSSL_cleanse(mac, sizeof(mac));
      return ret;
  }
  
  static void *x942kdf_new(void *provctx)
  {
      KDF_X942 *ctx;
  
      if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL)
          ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
      ctx->provctx = provctx;
      return ctx;
  }
  
  static void x942kdf_reset(void *vctx)
  {
      KDF_X942 *ctx = (KDF_X942 *)vctx;
      void *provctx = ctx->provctx;
  
      ossl_prov_digest_reset(&ctx->digest);
      OPENSSL_clear_free(ctx->secret, ctx->secret_len);
      OPENSSL_clear_free(ctx->ukm, ctx->ukm_len);
      memset(ctx, 0, sizeof(*ctx));
      ctx->provctx = provctx;
  }
  
  static void x942kdf_free(void *vctx)
  {
      KDF_X942 *ctx = (KDF_X942 *)vctx;
  
      if (ctx != NULL) {
          x942kdf_reset(ctx);
          OPENSSL_free(ctx);
      }
  }
  
  static int x942kdf_set_buffer(unsigned char **out, size_t *out_len,
                                const OSSL_PARAM *p)
  {
      if (p->data_size == 0 || p->data == NULL)
          return 1;
  
      OPENSSL_free(*out);
      *out = NULL;
      return OSSL_PARAM_get_octet_string(p, (void **)out, 0, out_len);
  }
  
  static size_t x942kdf_size(KDF_X942 *ctx)
  {
      int len;
      const EVP_MD *md = ossl_prov_digest_md(&ctx->digest);
  
      if (md == NULL) {
          ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
          return 0;
      }
      len = EVP_MD_size(md);
      return (len <= 0) ? 0 : (size_t)len;
  }
  
  static int x942kdf_derive(void *vctx, unsigned char *key, size_t keylen)
  {
      KDF_X942 *ctx = (KDF_X942 *)vctx;
      const EVP_MD *md = ossl_prov_digest_md(&ctx->digest);
      int ret = 0;
      unsigned char *ctr;
      unsigned char *der = NULL;
      size_t der_len = 0;
  
      if (ctx->secret == NULL) {
          ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SECRET);
          return 0;
      }
      if (md == NULL) {
          ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
          return 0;
      }
      if (ctx->cek_oid == NULL || ctx->cek_oid_len == 0) {
          ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_CEK_ALG);
          return 0;
      }
      if (ctx->ukm != NULL && ctx->ukm_len >= X942KDF_MAX_INLEN) {
          /*
           * Note the ukm length MUST be 512 bits.
           * For backwards compatibility the old check is being done.
           */
          ERR_raise(ERR_LIB_PROV, PROV_R_INAVLID_UKM_LENGTH);
          return 0;
      }
      /* generate the otherinfo der */
      if (!x942_encode_otherinfo(ctx->dkm_len,
                                 ctx->cek_oid, ctx->cek_oid_len,
                                 ctx->ukm, ctx->ukm_len,
                                 &der, &der_len, &ctr)) {
          ERR_raise(ERR_LIB_PROV, PROV_R_BAD_ENCODING);
          return 0;
      }
      ret = x942kdf_hash_kdm(md, ctx->secret, ctx->secret_len,
                             der, der_len, ctr, key, keylen);
      OPENSSL_free(der);
      return ret;
  }
  
  static int x942kdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
  {
      const OSSL_PARAM *p;
      KDF_X942 *ctx = vctx;
      OPENSSL_CTX *provctx = PROV_LIBRARY_CONTEXT_OF(ctx->provctx);
      size_t id;
  
      if (!ossl_prov_digest_load_from_params(&ctx->digest, params, provctx))
          return 0;
  
      if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SECRET)) != NULL
          || (p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY)) != NULL)
          if (!x942kdf_set_buffer(&ctx->secret, &ctx->secret_len, p))
              return 0;
  
      if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_UKM)) != NULL)
          if (!x942kdf_set_buffer(&ctx->ukm, &ctx->ukm_len, p))
              return 0;
  
      if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_CEK_ALG)) != NULL) {
          if (p->data_type != OSSL_PARAM_UTF8_STRING)
              return 0;
          if (find_alg_id(provctx, p->data, &id) == 0)
              return 0;
          ctx->cek_oid = kek_algs[id].oid;
          ctx->cek_oid_len = kek_algs[id].oid_len;
          ctx->dkm_len = kek_algs[id].keklen;
      }
      return 1;
  }
  
  static const OSSL_PARAM *x942kdf_settable_ctx_params(ossl_unused void *provctx)
  {
      static const OSSL_PARAM known_settable_ctx_params[] = {
          OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
          OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
          OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SECRET, NULL, 0),
          OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
          OSSL_PARAM_octet_string(OSSL_KDF_PARAM_UKM, NULL, 0),
          OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_CEK_ALG, NULL, 0),
          OSSL_PARAM_END
      };
      return known_settable_ctx_params;
  }
  
  static int x942kdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
  {
      KDF_X942 *ctx = (KDF_X942 *)vctx;
      OSSL_PARAM *p;
  
      if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
          return OSSL_PARAM_set_size_t(p, x942kdf_size(ctx));
      return -2;
  }
  
  static const OSSL_PARAM *x942kdf_gettable_ctx_params(ossl_unused void *provctx)
  {
      static const OSSL_PARAM known_gettable_ctx_params[] = {
          OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
          OSSL_PARAM_END
      };
      return known_gettable_ctx_params;
  }
  
  const OSSL_DISPATCH kdf_x942_kdf_functions[] = {
      { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))x942kdf_new },
      { OSSL_FUNC_KDF_FREECTX, (void(*)(void))x942kdf_free },
      { OSSL_FUNC_KDF_RESET, (void(*)(void))x942kdf_reset },
      { OSSL_FUNC_KDF_DERIVE, (void(*)(void))x942kdf_derive },
      { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
        (void(*)(void))x942kdf_settable_ctx_params },
      { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))x942kdf_set_ctx_params },
      { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
        (void(*)(void))x942kdf_gettable_ctx_params },
      { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))x942kdf_get_ctx_params },
      { 0, NULL }
  };
  