text: /*
   * Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.
   *
   * Licensed under the OpenSSL license (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 <stdio.h>
  #include <stdarg.h>
  #include <string.h>
  #include "internal/cryptlib.h"
  #include <openssl/evp.h>
  #include <openssl/kdf.h>
  #include "crypto/evp.h"
  #include "kdf_local.h"
  
  static void kdf_tls1_prf_reset(EVP_KDF_IMPL *impl);
  static int tls1_prf_alg(const EVP_MD *md,
                          const unsigned char *sec, size_t slen,
                          const unsigned char *seed, size_t seed_len,
                          unsigned char *out, size_t olen);
  
  #define TLS1_PRF_MAXBUF 1024
  
  /* TLS KDF kdf context structure */
  
  struct evp_kdf_impl_st {
      /* Digest to use for PRF */
      const EVP_MD *md;
      /* Secret value to use for PRF */
      unsigned char *sec;
      size_t seclen;
      /* Buffer of concatenated seed data */
      unsigned char seed[TLS1_PRF_MAXBUF];
      size_t seedlen;
  };
  
  static EVP_KDF_IMPL *kdf_tls1_prf_new(void)
  {
      EVP_KDF_IMPL *impl;
  
      if ((impl = OPENSSL_zalloc(sizeof(*impl))) == NULL)
          KDFerr(KDF_F_KDF_TLS1_PRF_NEW, ERR_R_MALLOC_FAILURE);
      return impl;
  }
  
  static void kdf_tls1_prf_free(EVP_KDF_IMPL *impl)
  {
      kdf_tls1_prf_reset(impl);
      OPENSSL_free(impl);
  }
  
  static void kdf_tls1_prf_reset(EVP_KDF_IMPL *impl)
  {
      OPENSSL_clear_free(impl->sec, impl->seclen);
      OPENSSL_cleanse(impl->seed, impl->seedlen);
      memset(impl, 0, sizeof(*impl));
  }
  
  static int kdf_tls1_prf_ctrl(EVP_KDF_IMPL *impl, int cmd, va_list args)
  {
      const unsigned char *p;
      size_t len;
      const EVP_MD *md;
  
      switch (cmd) {
      case EVP_KDF_CTRL_SET_MD:
          md = va_arg(args, const EVP_MD *);
          if (md == NULL)
              return 0;
  
          impl->md = md;
          return 1;
  
      case EVP_KDF_CTRL_SET_TLS_SECRET:
          p = va_arg(args, const unsigned char *);
          len = va_arg(args, size_t);
          OPENSSL_clear_free(impl->sec, impl->seclen);
          impl->sec = OPENSSL_memdup(p, len);
          if (impl->sec == NULL)
              return 0;
  
          impl->seclen  = len;
          return 1;
  
      case EVP_KDF_CTRL_RESET_TLS_SEED:
          OPENSSL_cleanse(impl->seed, impl->seedlen);
          impl->seedlen = 0;
          return 1;
  
      case EVP_KDF_CTRL_ADD_TLS_SEED:
          p = va_arg(args, const unsigned char *);
          len = va_arg(args, size_t);
          if (len == 0 || p == NULL)
              return 1;
  
          if (len > (TLS1_PRF_MAXBUF - impl->seedlen))
              return 0;
  
          memcpy(impl->seed + impl->seedlen, p, len);
          impl->seedlen += len;
          return 1;
  
      default:
          return -2;
      }
  }
  
  static int kdf_tls1_prf_ctrl_str(EVP_KDF_IMPL *impl,
                                   const char *type, const char *value)
  {
      if (value == NULL) {
          KDFerr(KDF_F_KDF_TLS1_PRF_CTRL_STR, KDF_R_VALUE_MISSING);
          return 0;
      }
      if (strcmp(type, "digest") == 0)
          return kdf_md2ctrl(impl, kdf_tls1_prf_ctrl, EVP_KDF_CTRL_SET_MD, value);
  
      if (strcmp(type, "secret") == 0)
          return kdf_str2ctrl(impl, kdf_tls1_prf_ctrl,
                              EVP_KDF_CTRL_SET_TLS_SECRET, value);
  
      if (strcmp(type, "hexsecret") == 0)
          return kdf_hex2ctrl(impl, kdf_tls1_prf_ctrl,
                              EVP_KDF_CTRL_SET_TLS_SECRET, value);
  
      if (strcmp(type, "seed") == 0)
          return kdf_str2ctrl(impl, kdf_tls1_prf_ctrl, EVP_KDF_CTRL_ADD_TLS_SEED,
                              value);
  
      if (strcmp(type, "hexseed") == 0)
          return kdf_hex2ctrl(impl, kdf_tls1_prf_ctrl, EVP_KDF_CTRL_ADD_TLS_SEED,
                              value);
  
      return -2;
  }
  
  static int kdf_tls1_prf_derive(EVP_KDF_IMPL *impl, unsigned char *key,
                                 size_t keylen)
  {
      if (impl->md == NULL) {
          KDFerr(KDF_F_KDF_TLS1_PRF_DERIVE, KDF_R_MISSING_MESSAGE_DIGEST);
          return 0;
      }
      if (impl->sec == NULL) {
          KDFerr(KDF_F_KDF_TLS1_PRF_DERIVE, KDF_R_MISSING_SECRET);
          return 0;
      }
      if (impl->seedlen == 0) {
          KDFerr(KDF_F_KDF_TLS1_PRF_DERIVE, KDF_R_MISSING_SEED);
          return 0;
      }
      return tls1_prf_alg(impl->md, impl->sec, impl->seclen,
                          impl->seed, impl->seedlen,
                          key, keylen);
  }
  
  const EVP_KDF_METHOD tls1_prf_kdf_meth = {
      EVP_KDF_TLS1_PRF,
      kdf_tls1_prf_new,
      kdf_tls1_prf_free,
      kdf_tls1_prf_reset,
      kdf_tls1_prf_ctrl,
      kdf_tls1_prf_ctrl_str,
      NULL,
      kdf_tls1_prf_derive
  };
  
  static int tls1_prf_P_hash(const EVP_MD *md,
                             const unsigned char *sec, size_t sec_len,
                             const unsigned char *seed, size_t seed_len,
                             unsigned char *out, size_t olen)
  {
      int chunk;
      EVP_MD_CTX *ctx = NULL, *ctx_tmp = NULL, *ctx_init = NULL;
      EVP_PKEY *mac_key = NULL;
      unsigned char A1[EVP_MAX_MD_SIZE];
      size_t A1_len;
      int ret = 0;
  
      chunk = EVP_MD_size(md);
      if (!ossl_assert(chunk > 0))
          goto err;
  
      ctx = EVP_MD_CTX_new();
      ctx_tmp = EVP_MD_CTX_new();
      ctx_init = EVP_MD_CTX_new();
      if (ctx == NULL || ctx_tmp == NULL || ctx_init == NULL)
          goto err;
      EVP_MD_CTX_set_flags(ctx_init, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
      mac_key = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL, sec, sec_len);
      if (mac_key == NULL)
          goto err;
      if (!EVP_DigestSignInit(ctx_init, NULL, md, NULL, mac_key))
          goto err;
      if (!EVP_MD_CTX_copy_ex(ctx, ctx_init))
          goto err;
      if (seed != NULL && !EVP_DigestSignUpdate(ctx, seed, seed_len))
          goto err;
      if (!EVP_DigestSignFinal(ctx, A1, &A1_len))
          goto err;
  
      for (;;) {
          /* Reinit mac contexts */
          if (!EVP_MD_CTX_copy_ex(ctx, ctx_init))
              goto err;
          if (!EVP_DigestSignUpdate(ctx, A1, A1_len))
              goto err;
          if (olen > (size_t)chunk && !EVP_MD_CTX_copy_ex(ctx_tmp, ctx))
              goto err;
          if (seed && !EVP_DigestSignUpdate(ctx, seed, seed_len))
              goto err;
  
          if (olen > (size_t)chunk) {
              size_t mac_len;
              if (!EVP_DigestSignFinal(ctx, out, &mac_len))
                  goto err;
              out += mac_len;
              olen -= mac_len;
              /* calc the next A1 value */
              if (!EVP_DigestSignFinal(ctx_tmp, A1, &A1_len))
                  goto err;
          } else {                /* last one */
  
              if (!EVP_DigestSignFinal(ctx, A1, &A1_len))
                  goto err;
              memcpy(out, A1, olen);
              break;
          }
      }
      ret = 1;
   err:
      EVP_PKEY_free(mac_key);
      EVP_MD_CTX_free(ctx);
      EVP_MD_CTX_free(ctx_tmp);
      EVP_MD_CTX_free(ctx_init);
      OPENSSL_cleanse(A1, sizeof(A1));
      return ret;
  }
  
  static int tls1_prf_alg(const EVP_MD *md,
                          const unsigned char *sec, size_t slen,
                          const unsigned char *seed, size_t seed_len,
                          unsigned char *out, size_t olen)
  {
      if (EVP_MD_type(md) == NID_md5_sha1) {
          size_t i;
          unsigned char *tmp;
          if (!tls1_prf_P_hash(EVP_md5(), sec, slen/2 + (slen & 1),
                               seed, seed_len, out, olen))
              return 0;
  
          if ((tmp = OPENSSL_malloc(olen)) == NULL) {
              KDFerr(KDF_F_TLS1_PRF_ALG, ERR_R_MALLOC_FAILURE);
              return 0;
          }
          if (!tls1_prf_P_hash(EVP_sha1(), sec + slen/2, slen/2 + (slen & 1),
                               seed, seed_len, tmp, olen)) {
              OPENSSL_clear_free(tmp, olen);
              return 0;
          }
          for (i = 0; i < olen; i++)
              out[i] ^= tmp[i];
          OPENSSL_clear_free(tmp, olen);
          return 1;
      }
      if (!tls1_prf_P_hash(md, sec, slen, seed, seed_len, out, olen))
          return 0;
  
      return 1;
  }
  