text: /*
   * Copyright 1995-2019 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 "internal/cryptlib.h"
  #include <openssl/objects.h>
  #include <openssl/evp.h>
  #include <openssl/engine.h>
  #include "crypto/evp.h"
  #include "evp_local.h"
  
  /* This call frees resources associated with the context */
  int EVP_MD_CTX_reset(EVP_MD_CTX *ctx)
  {
      if (ctx == NULL)
          return 1;
  
      /*
       * Don't assume ctx->md_data was cleaned in EVP_Digest_Final, because
       * sometimes only copies of the context are ever finalised.
       */
      if (ctx->digest && ctx->digest->cleanup
          && !EVP_MD_CTX_test_flags(ctx, EVP_MD_CTX_FLAG_CLEANED))
          ctx->digest->cleanup(ctx);
      if (ctx->digest && ctx->digest->ctx_size && ctx->md_data
          && !EVP_MD_CTX_test_flags(ctx, EVP_MD_CTX_FLAG_REUSE)) {
          OPENSSL_clear_free(ctx->md_data, ctx->digest->ctx_size);
      }
      /*
       * pctx should be freed by the user of EVP_MD_CTX
       * if EVP_MD_CTX_FLAG_KEEP_PKEY_CTX is set
       */
      if (!EVP_MD_CTX_test_flags(ctx, EVP_MD_CTX_FLAG_KEEP_PKEY_CTX))
          EVP_PKEY_CTX_free(ctx->pctx);
  #ifndef OPENSSL_NO_ENGINE
      ENGINE_finish(ctx->engine);
  #endif
      OPENSSL_cleanse(ctx, sizeof(*ctx));
  
      return 1;
  }
  
  EVP_MD_CTX *EVP_MD_CTX_new(void)
  {
      return OPENSSL_zalloc(sizeof(EVP_MD_CTX));
  }
  
  void EVP_MD_CTX_free(EVP_MD_CTX *ctx)
  {
      EVP_MD_CTX_reset(ctx);
      OPENSSL_free(ctx);
  }
  
  int EVP_DigestInit(EVP_MD_CTX *ctx, const EVP_MD *type)
  {
      EVP_MD_CTX_reset(ctx);
      return EVP_DigestInit_ex(ctx, type, NULL);
  }
  
  int EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl)
  {
      EVP_MD_CTX_clear_flags(ctx, EVP_MD_CTX_FLAG_CLEANED);
  #ifndef OPENSSL_NO_ENGINE
      /*
       * Whether it's nice or not, "Inits" can be used on "Final"'d contexts so
       * this context may already have an ENGINE! Try to avoid releasing the
       * previous handle, re-querying for an ENGINE, and having a
       * reinitialisation, when it may all be unnecessary.
       */
      if (ctx->engine && ctx->digest &&
          (type == NULL || (type->type == ctx->digest->type)))
          goto skip_to_init;
      if (type) {
          /*
           * Ensure an ENGINE left lying around from last time is cleared (the
           * previous check attempted to avoid this if the same ENGINE and
           * EVP_MD could be used).
           */
          ENGINE_finish(ctx->engine);
          if (impl != NULL) {
              if (!ENGINE_init(impl)) {
                  EVPerr(EVP_F_EVP_DIGESTINIT_EX, EVP_R_INITIALIZATION_ERROR);
                  return 0;
              }
          } else {
              /* Ask if an ENGINE is reserved for this job */
              impl = ENGINE_get_digest_engine(type->type);
          }
          if (impl != NULL) {
              /* There's an ENGINE for this job ... (apparently) */
              const EVP_MD *d = ENGINE_get_digest(impl, type->type);
  
              if (d == NULL) {
                  EVPerr(EVP_F_EVP_DIGESTINIT_EX, EVP_R_INITIALIZATION_ERROR);
                  ENGINE_finish(impl);
                  return 0;
              }
              /* We'll use the ENGINE's private digest definition */
              type = d;
              /*
               * Store the ENGINE functional reference so we know 'type' came
               * from an ENGINE and we need to release it when done.
               */
              ctx->engine = impl;
          } else
              ctx->engine = NULL;
      } else {
          if (!ctx->digest) {
              EVPerr(EVP_F_EVP_DIGESTINIT_EX, EVP_R_NO_DIGEST_SET);
              return 0;
          }
          type = ctx->digest;
      }
  #endif
      if (ctx->digest != type) {
          if (ctx->digest && ctx->digest->ctx_size) {
              OPENSSL_clear_free(ctx->md_data, ctx->digest->ctx_size);
              ctx->md_data = NULL;
          }
          ctx->digest = type;
          if (!(ctx->flags & EVP_MD_CTX_FLAG_NO_INIT) && type->ctx_size) {
              ctx->update = type->update;
              ctx->md_data = OPENSSL_zalloc(type->ctx_size);
              if (ctx->md_data == NULL) {
                  EVPerr(EVP_F_EVP_DIGESTINIT_EX, ERR_R_MALLOC_FAILURE);
                  return 0;
              }
          }
      }
  #ifndef OPENSSL_NO_ENGINE
   skip_to_init:
  #endif
      if (ctx->pctx) {
          int r;
          r = EVP_PKEY_CTX_ctrl(ctx->pctx, -1, EVP_PKEY_OP_TYPE_SIG,
                                EVP_PKEY_CTRL_DIGESTINIT, 0, ctx);
          if (r <= 0 && (r != -2))
              return 0;
      }
      if (ctx->flags & EVP_MD_CTX_FLAG_NO_INIT)
          return 1;
      return ctx->digest->init(ctx);
  }
  
  int EVP_DigestUpdate(EVP_MD_CTX *ctx, const void *data, size_t count)
  {
      if (count == 0)
          return 1;
  
      return ctx->update(ctx, data, count);
  }
  
  /* The caller can assume that this removes any secret data from the context */
  int EVP_DigestFinal(EVP_MD_CTX *ctx, unsigned char *md, unsigned int *size)
  {
      int ret;
      ret = EVP_DigestFinal_ex(ctx, md, size);
      EVP_MD_CTX_reset(ctx);
      return ret;
  }
  
  /* The caller can assume that this removes any secret data from the context */
  int EVP_DigestFinal_ex(EVP_MD_CTX *ctx, unsigned char *md, unsigned int *size)
  {
      int ret;
  
      OPENSSL_assert(ctx->digest->md_size <= EVP_MAX_MD_SIZE);
      ret = ctx->digest->final(ctx, md);
      if (size != NULL)
          *size = ctx->digest->md_size;
      if (ctx->digest->cleanup) {
          ctx->digest->cleanup(ctx);
          EVP_MD_CTX_set_flags(ctx, EVP_MD_CTX_FLAG_CLEANED);
      }
      OPENSSL_cleanse(ctx->md_data, ctx->digest->ctx_size);
      return ret;
  }
  
  int EVP_DigestFinalXOF(EVP_MD_CTX *ctx, unsigned char *md, size_t size)
  {
      int ret = 0;
  
      if (ctx->digest->flags & EVP_MD_FLAG_XOF
          && size <= INT_MAX
          && ctx->digest->md_ctrl(ctx, EVP_MD_CTRL_XOF_LEN, (int)size, NULL)) {
          ret = ctx->digest->final(ctx, md);
  
          if (ctx->digest->cleanup != NULL) {
              ctx->digest->cleanup(ctx);
              EVP_MD_CTX_set_flags(ctx, EVP_MD_CTX_FLAG_CLEANED);
          }
          OPENSSL_cleanse(ctx->md_data, ctx->digest->ctx_size);
      } else {
          EVPerr(EVP_F_EVP_DIGESTFINALXOF, EVP_R_NOT_XOF_OR_INVALID_LENGTH);
      }
  
      return ret;
  }
  
  int EVP_MD_CTX_copy(EVP_MD_CTX *out, const EVP_MD_CTX *in)
  {
      EVP_MD_CTX_reset(out);
      return EVP_MD_CTX_copy_ex(out, in);
  }
  
  int EVP_MD_CTX_copy_ex(EVP_MD_CTX *out, const EVP_MD_CTX *in)
  {
      unsigned char *tmp_buf;
      if ((in == NULL) || (in->digest == NULL)) {
          EVPerr(EVP_F_EVP_MD_CTX_COPY_EX, EVP_R_INPUT_NOT_INITIALIZED);
          return 0;
      }
  #ifndef OPENSSL_NO_ENGINE
      /* Make sure it's safe to copy a digest context using an ENGINE */
      if (in->engine && !ENGINE_init(in->engine)) {
          EVPerr(EVP_F_EVP_MD_CTX_COPY_EX, ERR_R_ENGINE_LIB);
          return 0;
      }
  #endif
  
      if (out->digest == in->digest) {
          tmp_buf = out->md_data;
          EVP_MD_CTX_set_flags(out, EVP_MD_CTX_FLAG_REUSE);
      } else
          tmp_buf = NULL;
      EVP_MD_CTX_reset(out);
      memcpy(out, in, sizeof(*out));
  
      /* copied EVP_MD_CTX should free the copied EVP_PKEY_CTX */
      EVP_MD_CTX_clear_flags(out, EVP_MD_CTX_FLAG_KEEP_PKEY_CTX);
  
      /* Null these variables, since they are getting fixed up
       * properly below.  Anything else may cause a memleak and/or
       * double free if any of the memory allocations below fail
       */
      out->md_data = NULL;
      out->pctx = NULL;
  
      if (in->md_data && out->digest->ctx_size) {
          if (tmp_buf)
              out->md_data = tmp_buf;
          else {
              out->md_data = OPENSSL_malloc(out->digest->ctx_size);
              if (out->md_data == NULL) {
                  EVPerr(EVP_F_EVP_MD_CTX_COPY_EX, ERR_R_MALLOC_FAILURE);
                  return 0;
              }
          }
          memcpy(out->md_data, in->md_data, out->digest->ctx_size);
      }
  
      out->update = in->update;
  
      if (in->pctx) {
          out->pctx = EVP_PKEY_CTX_dup(in->pctx);
          if (!out->pctx) {
              EVP_MD_CTX_reset(out);
              return 0;
          }
      }
  
      if (out->digest->copy)
          return out->digest->copy(out, in);
  
      return 1;
  }
  
  int EVP_Digest(const void *data, size_t count,
                 unsigned char *md, unsigned int *size, const EVP_MD *type,
                 ENGINE *impl)
  {
      EVP_MD_CTX *ctx = EVP_MD_CTX_new();
      int ret;
  
      if (ctx == NULL)
          return 0;
      EVP_MD_CTX_set_flags(ctx, EVP_MD_CTX_FLAG_ONESHOT);
      ret = EVP_DigestInit_ex(ctx, type, impl)
          && EVP_DigestUpdate(ctx, data, count)
          && EVP_DigestFinal_ex(ctx, md, size);
      EVP_MD_CTX_free(ctx);
  
      return ret;
  }
  
  int EVP_MD_CTX_ctrl(EVP_MD_CTX *ctx, int cmd, int p1, void *p2)
  {
      if (ctx->digest && ctx->digest->md_ctrl) {
          int ret = ctx->digest->md_ctrl(ctx, cmd, p1, p2);
          if (ret <= 0)
              return 0;
          return 1;
      }
      return 0;
  }
  