text: /*
   * Copyright 2017-2019 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 "e_os.h"
  #include <string.h>
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <fcntl.h>
  #include <sys/ioctl.h>
  #include <unistd.h>
  #include <assert.h>
  
  #include <openssl/conf.h>
  #include <openssl/evp.h>
  #include <openssl/err.h>
  #include <openssl/engine.h>
  #include <openssl/objects.h>
  #include <crypto/cryptodev.h>
  
  #include "crypto/engine.h"
  
  /* #define ENGINE_DEVCRYPTO_DEBUG */
  
  #if CRYPTO_ALGORITHM_MIN < CRYPTO_ALGORITHM_MAX
  # define CHECK_BSD_STYLE_MACROS
  #endif
  
  /*
   * ONE global file descriptor for all sessions.  This allows operations
   * such as digest session data copying (see digest_copy()), but is also
   * saner...  why re-open /dev/crypto for every session?
   */
  static int cfd;
  #define DEVCRYPTO_REQUIRE_ACCELERATED 0 /* require confirmation of acceleration */
  #define DEVCRYPTO_USE_SOFTWARE        1 /* allow software drivers */
  #define DEVCRYPTO_REJECT_SOFTWARE     2 /* only disallow confirmed software drivers */
  
  #define DEVCRYPTO_DEFAULT_USE_SOFDTRIVERS DEVCRYPTO_REJECT_SOFTWARE
  static int use_softdrivers = DEVCRYPTO_DEFAULT_USE_SOFDTRIVERS;
  
  /*
   * cipher/digest status & acceleration definitions
   * Make sure the defaults are set to 0
   */
  struct driver_info_st {
      enum devcrypto_status_t {
          DEVCRYPTO_STATUS_FAILURE         = -3, /* unusable for other reason */
          DEVCRYPTO_STATUS_NO_CIOCCPHASH   = -2, /* hash state copy not supported */
          DEVCRYPTO_STATUS_NO_CIOCGSESSION = -1, /* session open failed */
          DEVCRYPTO_STATUS_UNKNOWN         =  0, /* not tested yet */
          DEVCRYPTO_STATUS_USABLE          =  1  /* algo can be used */
      } status;
  
      enum devcrypto_accelerated_t {
          DEVCRYPTO_NOT_ACCELERATED        = -1, /* software implemented */
          DEVCRYPTO_ACCELERATION_UNKNOWN   =  0, /* acceleration support unkown */
          DEVCRYPTO_ACCELERATED            =  1  /* hardware accelerated */
      } accelerated;
  
      char *driver_name;
  };
  
  static int clean_devcrypto_session(struct session_op *sess) {
      if (ioctl(cfd, CIOCFSESSION, &sess->ses) < 0) {
          SYSerr(SYS_F_IOCTL, errno);
          return 0;
      }
      memset(sess, 0, sizeof(struct session_op));
      return 1;
  }
  
  /******************************************************************************
   *
   * Ciphers
   *
   * Because they all do the same basic operation, we have only one set of
   * method functions for them all to share, and a mapping table between
   * NIDs and cryptodev IDs, with all the necessary size data.
   *
   *****/
  
  struct cipher_ctx {
      struct session_op sess;
      int op;                      /* COP_ENCRYPT or COP_DECRYPT */
      unsigned long mode;          /* EVP_CIPH_*_MODE */
  
      /* to handle ctr mode being a stream cipher */
      unsigned char partial[EVP_MAX_BLOCK_LENGTH];
      unsigned int blocksize, num;
  };
  
  static const struct cipher_data_st {
      int nid;
      int blocksize;
      int keylen;
      int ivlen;
      int flags;
      int devcryptoid;
  } cipher_data[] = {
  #ifndef OPENSSL_NO_DES
      { NID_des_cbc, 8, 8, 8, EVP_CIPH_CBC_MODE, CRYPTO_DES_CBC },
      { NID_des_ede3_cbc, 8, 24, 8, EVP_CIPH_CBC_MODE, CRYPTO_3DES_CBC },
  #endif
  #ifndef OPENSSL_NO_BF
      { NID_bf_cbc, 8, 16, 8, EVP_CIPH_CBC_MODE, CRYPTO_BLF_CBC },
  #endif
  #ifndef OPENSSL_NO_CAST
      { NID_cast5_cbc, 8, 16, 8, EVP_CIPH_CBC_MODE, CRYPTO_CAST_CBC },
  #endif
      { NID_aes_128_cbc, 16, 128 / 8, 16, EVP_CIPH_CBC_MODE, CRYPTO_AES_CBC },
      { NID_aes_192_cbc, 16, 192 / 8, 16, EVP_CIPH_CBC_MODE, CRYPTO_AES_CBC },
      { NID_aes_256_cbc, 16, 256 / 8, 16, EVP_CIPH_CBC_MODE, CRYPTO_AES_CBC },
  #ifndef OPENSSL_NO_RC4
      { NID_rc4, 1, 16, 0, EVP_CIPH_STREAM_CIPHER, CRYPTO_ARC4 },
  #endif
  #if !defined(CHECK_BSD_STYLE_MACROS) || defined(CRYPTO_AES_CTR)
      { NID_aes_128_ctr, 16, 128 / 8, 16, EVP_CIPH_CTR_MODE, CRYPTO_AES_CTR },
      { NID_aes_192_ctr, 16, 192 / 8, 16, EVP_CIPH_CTR_MODE, CRYPTO_AES_CTR },
      { NID_aes_256_ctr, 16, 256 / 8, 16, EVP_CIPH_CTR_MODE, CRYPTO_AES_CTR },
  #endif
  #if 0                            /* Not yet supported */
      { NID_aes_128_xts, 16, 128 / 8 * 2, 16, EVP_CIPH_XTS_MODE, CRYPTO_AES_XTS },
      { NID_aes_256_xts, 16, 256 / 8 * 2, 16, EVP_CIPH_XTS_MODE, CRYPTO_AES_XTS },
  #endif
  #if !defined(CHECK_BSD_STYLE_MACROS) || defined(CRYPTO_AES_ECB)
      { NID_aes_128_ecb, 16, 128 / 8, 0, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB },
      { NID_aes_192_ecb, 16, 192 / 8, 0, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB },
      { NID_aes_256_ecb, 16, 256 / 8, 0, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB },
  #endif
  #if 0                            /* Not yet supported */
      { NID_aes_128_gcm, 16, 128 / 8, 16, EVP_CIPH_GCM_MODE, CRYPTO_AES_GCM },
      { NID_aes_192_gcm, 16, 192 / 8, 16, EVP_CIPH_GCM_MODE, CRYPTO_AES_GCM },
      { NID_aes_256_gcm, 16, 256 / 8, 16, EVP_CIPH_GCM_MODE, CRYPTO_AES_GCM },
  #endif
  #ifndef OPENSSL_NO_CAMELLIA
      { NID_camellia_128_cbc, 16, 128 / 8, 16, EVP_CIPH_CBC_MODE,
        CRYPTO_CAMELLIA_CBC },
      { NID_camellia_192_cbc, 16, 192 / 8, 16, EVP_CIPH_CBC_MODE,
        CRYPTO_CAMELLIA_CBC },
      { NID_camellia_256_cbc, 16, 256 / 8, 16, EVP_CIPH_CBC_MODE,
        CRYPTO_CAMELLIA_CBC },
  #endif
  };
  
  static size_t find_cipher_data_index(int nid)
  {
      size_t i;
  
      for (i = 0; i < OSSL_NELEM(cipher_data); i++)
          if (nid == cipher_data[i].nid)
              return i;
      return (size_t)-1;
  }
  
  static size_t get_cipher_data_index(int nid)
  {
      size_t i = find_cipher_data_index(nid);
  
      if (i != (size_t)-1)
          return i;
  
      /*
       * Code further down must make sure that only NIDs in the table above
       * are used.  If any other NID reaches this function, there's a grave
       * coding error further down.
       */
      assert("Code that never should be reached" == NULL);
      return -1;
  }
  
  static const struct cipher_data_st *get_cipher_data(int nid)
  {
      return &cipher_data[get_cipher_data_index(nid)];
  }
  
  /*
   * Following are the three necessary functions to map OpenSSL functionality
   * with cryptodev.
   */
  
  static int cipher_init(EVP_CIPHER_CTX *ctx, const unsigned char *key,
                         const unsigned char *iv, int enc)
  {
      struct cipher_ctx *cipher_ctx =
          (struct cipher_ctx *)EVP_CIPHER_CTX_get_cipher_data(ctx);
      const struct cipher_data_st *cipher_d =
          get_cipher_data(EVP_CIPHER_CTX_nid(ctx));
  
      /* cleanup a previous session */
      if (cipher_ctx->sess.ses != 0 &&
          clean_devcrypto_session(&cipher_ctx->sess) == 0)
          return 0;
  
      cipher_ctx->sess.cipher = cipher_d->devcryptoid;
      cipher_ctx->sess.keylen = cipher_d->keylen;
      cipher_ctx->sess.key = (void *)key;
      cipher_ctx->op = enc ? COP_ENCRYPT : COP_DECRYPT;
      cipher_ctx->mode = cipher_d->flags & EVP_CIPH_MODE;
      cipher_ctx->blocksize = cipher_d->blocksize;
      if (ioctl(cfd, CIOCGSESSION, &cipher_ctx->sess) < 0) {
          SYSerr(SYS_F_IOCTL, errno);
          return 0;
      }
  
      return 1;
  }
  
  static int cipher_do_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
                              const unsigned char *in, size_t inl)
  {
      struct cipher_ctx *cipher_ctx =
          (struct cipher_ctx *)EVP_CIPHER_CTX_get_cipher_data(ctx);
      struct crypt_op cryp;
      unsigned char *iv = EVP_CIPHER_CTX_iv_noconst(ctx);
  #if !defined(COP_FLAG_WRITE_IV)
      unsigned char saved_iv[EVP_MAX_IV_LENGTH];
      const unsigned char *ivptr;
      size_t nblocks, ivlen;
  #endif
  
      memset(&cryp, 0, sizeof(cryp));
      cryp.ses = cipher_ctx->sess.ses;
      cryp.len = inl;
      cryp.src = (void *)in;
      cryp.dst = (void *)out;
      cryp.iv = (void *)iv;
      cryp.op = cipher_ctx->op;
  #if !defined(COP_FLAG_WRITE_IV)
      cryp.flags = 0;
  
      ivlen = EVP_CIPHER_CTX_iv_length(ctx);
      if (ivlen > 0)
          switch (cipher_ctx->mode) {
          case EVP_CIPH_CBC_MODE:
              assert(inl >= ivlen);
              if (!EVP_CIPHER_CTX_encrypting(ctx)) {
                  ivptr = in + inl - ivlen;
                  memcpy(saved_iv, ivptr, ivlen);
              }
              break;
  
          case EVP_CIPH_CTR_MODE:
              break;
  
          default: /* should not happen */
              return 0;
          }
  #else
      cryp.flags = COP_FLAG_WRITE_IV;
  #endif
  
      if (ioctl(cfd, CIOCCRYPT, &cryp) < 0) {
          SYSerr(SYS_F_IOCTL, errno);
          return 0;
      }
  
  #if !defined(COP_FLAG_WRITE_IV)
      if (ivlen > 0)
          switch (cipher_ctx->mode) {
          case EVP_CIPH_CBC_MODE:
              assert(inl >= ivlen);
              if (EVP_CIPHER_CTX_encrypting(ctx))
                  ivptr = out + inl - ivlen;
              else
                  ivptr = saved_iv;
  
              memcpy(iv, ivptr, ivlen);
              break;
  
          case EVP_CIPH_CTR_MODE:
              nblocks = (inl + cipher_ctx->blocksize - 1)
                        / cipher_ctx->blocksize;
              do {
                  ivlen--;
                  nblocks += iv[ivlen];
                  iv[ivlen] = (uint8_t) nblocks;
                  nblocks >>= 8;
              } while (ivlen);
              break;
  
          default: /* should not happen */
              return 0;
          }
  #endif
  
      return 1;
  }
  
  static int ctr_do_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
                           const unsigned char *in, size_t inl)
  {
      struct cipher_ctx *cipher_ctx =
          (struct cipher_ctx *)EVP_CIPHER_CTX_get_cipher_data(ctx);
      size_t nblocks, len;
  
      /* initial partial block */
      while (cipher_ctx->num && inl) {
          (*out++) = *(in++) ^ cipher_ctx->partial[cipher_ctx->num];
          --inl;
          cipher_ctx->num = (cipher_ctx->num + 1) % cipher_ctx->blocksize;
      }
  
      /* full blocks */
      if (inl > (unsigned int) cipher_ctx->blocksize) {
          nblocks = inl/cipher_ctx->blocksize;
          len = nblocks * cipher_ctx->blocksize;
          if (cipher_do_cipher(ctx, out, in, len) < 1)
              return 0;
          inl -= len;
          out += len;
          in += len;
      }
  
      /* final partial block */
      if (inl) {
          memset(cipher_ctx->partial, 0, cipher_ctx->blocksize);
          if (cipher_do_cipher(ctx, cipher_ctx->partial, cipher_ctx->partial,
              cipher_ctx->blocksize) < 1)
              return 0;
          while (inl--) {
              out[cipher_ctx->num] = in[cipher_ctx->num]
                                     ^ cipher_ctx->partial[cipher_ctx->num];
              cipher_ctx->num++;
          }
      }
  
      return 1;
  }
  
  static int cipher_ctrl(EVP_CIPHER_CTX *ctx, int type, int p1, void* p2)
  {
      struct cipher_ctx *cipher_ctx =
          (struct cipher_ctx *)EVP_CIPHER_CTX_get_cipher_data(ctx);
      EVP_CIPHER_CTX *to_ctx = (EVP_CIPHER_CTX *)p2;
      struct cipher_ctx *to_cipher_ctx;
  
      switch (type) {
      case EVP_CTRL_COPY:
          if (cipher_ctx == NULL)
              return 1;
          /* when copying the context, a new session needs to be initialized */
          to_cipher_ctx =
              (struct cipher_ctx *)EVP_CIPHER_CTX_get_cipher_data(to_ctx);
          memset(&to_cipher_ctx->sess, 0, sizeof(to_cipher_ctx->sess));
          return cipher_init(to_ctx, cipher_ctx->sess.key, EVP_CIPHER_CTX_iv(ctx),
                             (cipher_ctx->op == COP_ENCRYPT));
  
      case EVP_CTRL_INIT:
          memset(&cipher_ctx->sess, 0, sizeof(cipher_ctx->sess));
          return 1;
  
      default:
          break;
      }
  
      return -1;
  }
  
  static int cipher_cleanup(EVP_CIPHER_CTX *ctx)
  {
      struct cipher_ctx *cipher_ctx =
          (struct cipher_ctx *)EVP_CIPHER_CTX_get_cipher_data(ctx);
  
      return clean_devcrypto_session(&cipher_ctx->sess);
  }
  
  /*
   * Keep tables of known nids, associated methods, selected ciphers, and driver
   * info.
   * Note that known_cipher_nids[] isn't necessarily indexed the same way as
   * cipher_data[] above, which the other tables are.
   */
  static int known_cipher_nids[OSSL_NELEM(cipher_data)];
  static int known_cipher_nids_amount = -1; /* -1 indicates not yet initialised */
  static EVP_CIPHER *known_cipher_methods[OSSL_NELEM(cipher_data)] = { NULL, };
  static int selected_ciphers[OSSL_NELEM(cipher_data)];
  static struct driver_info_st cipher_driver_info[OSSL_NELEM(cipher_data)];
  
  
  static int devcrypto_test_cipher(size_t cipher_data_index)
  {
      return (cipher_driver_info[cipher_data_index].status == DEVCRYPTO_STATUS_USABLE
              && selected_ciphers[cipher_data_index] == 1
              && (cipher_driver_info[cipher_data_index].accelerated
                      == DEVCRYPTO_ACCELERATED
                  || use_softdrivers == DEVCRYPTO_USE_SOFTWARE
                  || (cipher_driver_info[cipher_data_index].accelerated
                          != DEVCRYPTO_NOT_ACCELERATED
                      && use_softdrivers == DEVCRYPTO_REJECT_SOFTWARE)));
  }
  
  static void prepare_cipher_methods(void)
  {
      size_t i;
      struct session_op sess;
      unsigned long cipher_mode;
  #ifdef CIOCGSESSINFO
      struct session_info_op siop;
  #endif
  
      memset(&cipher_driver_info, 0, sizeof(cipher_driver_info));
  
      memset(&sess, 0, sizeof(sess));
      sess.key = (void *)"01234567890123456789012345678901234567890123456789";
  
      for (i = 0, known_cipher_nids_amount = 0;
           i < OSSL_NELEM(cipher_data); i++) {
  
          selected_ciphers[i] = 1;
          /*
           * Check that the cipher is usable
           */
          sess.cipher = cipher_data[i].devcryptoid;
          sess.keylen = cipher_data[i].keylen;
          if (ioctl(cfd, CIOCGSESSION, &sess) < 0) {
              cipher_driver_info[i].status = DEVCRYPTO_STATUS_NO_CIOCGSESSION;
              continue;
          }
  
          cipher_mode = cipher_data[i].flags & EVP_CIPH_MODE;
  
          if ((known_cipher_methods[i] =
                   EVP_CIPHER_meth_new(cipher_data[i].nid,
                                       cipher_mode == EVP_CIPH_CTR_MODE ? 1 :
                                                      cipher_data[i].blocksize,
                                       cipher_data[i].keylen)) == NULL
              || !EVP_CIPHER_meth_set_iv_length(known_cipher_methods[i],
                                                cipher_data[i].ivlen)
              || !EVP_CIPHER_meth_set_flags(known_cipher_methods[i],
                                            cipher_data[i].flags
                                            | EVP_CIPH_CUSTOM_COPY
                                            | EVP_CIPH_CTRL_INIT
                                            | EVP_CIPH_FLAG_DEFAULT_ASN1)
              || !EVP_CIPHER_meth_set_init(known_cipher_methods[i], cipher_init)
              || !EVP_CIPHER_meth_set_do_cipher(known_cipher_methods[i],
                                       cipher_mode == EVP_CIPH_CTR_MODE ?
                                                ctr_do_cipher :
                                                cipher_do_cipher)
              || !EVP_CIPHER_meth_set_ctrl(known_cipher_methods[i], cipher_ctrl)
              || !EVP_CIPHER_meth_set_cleanup(known_cipher_methods[i],
                                              cipher_cleanup)
              || !EVP_CIPHER_meth_set_impl_ctx_size(known_cipher_methods[i],
                                                    sizeof(struct cipher_ctx))) {
              cipher_driver_info[i].status = DEVCRYPTO_STATUS_FAILURE;
              EVP_CIPHER_meth_free(known_cipher_methods[i]);
              known_cipher_methods[i] = NULL;
          } else {
              cipher_driver_info[i].status = DEVCRYPTO_STATUS_USABLE;
  #ifdef CIOCGSESSINFO
              siop.ses = sess.ses;
              if (ioctl(cfd, CIOCGSESSINFO, &siop) < 0) {
                  cipher_driver_info[i].accelerated = DEVCRYPTO_ACCELERATION_UNKNOWN;
              } else {
                  cipher_driver_info[i].driver_name =
                      OPENSSL_strndup(siop.cipher_info.cra_driver_name,
                                      CRYPTODEV_MAX_ALG_NAME);
                  if (!(siop.flags & SIOP_FLAG_KERNEL_DRIVER_ONLY))
                      cipher_driver_info[i].accelerated = DEVCRYPTO_NOT_ACCELERATED;
                  else
                      cipher_driver_info[i].accelerated = DEVCRYPTO_ACCELERATED;
              }
  #endif /* CIOCGSESSINFO */
          }
          ioctl(cfd, CIOCFSESSION, &sess.ses);
          if (devcrypto_test_cipher(i)) {
              known_cipher_nids[known_cipher_nids_amount++] =
                  cipher_data[i].nid;
          }
      }
  }
  
  static void rebuild_known_cipher_nids(ENGINE *e)
  {
      size_t i;
  
      for (i = 0, known_cipher_nids_amount = 0; i < OSSL_NELEM(cipher_data); i++) {
          if (devcrypto_test_cipher(i))
              known_cipher_nids[known_cipher_nids_amount++] = cipher_data[i].nid;
      }
      ENGINE_unregister_ciphers(e);
      ENGINE_register_ciphers(e);
  }
  
  static const EVP_CIPHER *get_cipher_method(int nid)
  {
      size_t i = get_cipher_data_index(nid);
  
      if (i == (size_t)-1)
          return NULL;
      return known_cipher_methods[i];
  }
  
  static int get_cipher_nids(const int **nids)
  {
      *nids = known_cipher_nids;
      return known_cipher_nids_amount;
  }
  
  static void destroy_cipher_method(int nid)
  {
      size_t i = get_cipher_data_index(nid);
  
      EVP_CIPHER_meth_free(known_cipher_methods[i]);
      known_cipher_methods[i] = NULL;
  }
  
  static void destroy_all_cipher_methods(void)
  {
      size_t i;
  
      for (i = 0; i < OSSL_NELEM(cipher_data); i++) {
          destroy_cipher_method(cipher_data[i].nid);
          OPENSSL_free(cipher_driver_info[i].driver_name);
          cipher_driver_info[i].driver_name = NULL;
      }
  }
  
  static int devcrypto_ciphers(ENGINE *e, const EVP_CIPHER **cipher,
                               const int **nids, int nid)
  {
      if (cipher == NULL)
          return get_cipher_nids(nids);
  
      *cipher = get_cipher_method(nid);
  
      return *cipher != NULL;
  }
  
  static void devcrypto_select_all_ciphers(int *cipher_list)
  {
      size_t i;
  
      for (i = 0; i < OSSL_NELEM(cipher_data); i++)
          cipher_list[i] = 1;
  }
  
  static int cryptodev_select_cipher_cb(const char *str, int len, void *usr)
  {
      int *cipher_list = (int *)usr;
      char *name;
      const EVP_CIPHER *EVP;
      size_t i;
  
      if (len == 0)
          return 1;
      if (usr == NULL || (name = OPENSSL_strndup(str, len)) == NULL)
          return 0;
      EVP = EVP_get_cipherbyname(name);
      if (EVP == NULL)
          fprintf(stderr, "devcrypto: unknown cipher %s\n", name);
      else if ((i = find_cipher_data_index(EVP_CIPHER_nid(EVP))) != (size_t)-1)
          cipher_list[i] = 1;
      else
          fprintf(stderr, "devcrypto: cipher %s not available\n", name);
      OPENSSL_free(name);
      return 1;
  }
  
  static void dump_cipher_info(void)
  {
      size_t i;
      const char *name;
  
      fprintf (stderr, "Information about ciphers supported by the /dev/crypto"
               " engine:\n");
  #ifndef CIOCGSESSINFO
      fprintf(stderr, "CIOCGSESSINFO (session info call) unavailable\n");
  #endif
      for (i = 0; i < OSSL_NELEM(cipher_data); i++) {
          name = OBJ_nid2sn(cipher_data[i].nid);
          fprintf (stderr, "Cipher %s, NID=%d, /dev/crypto info: id=%d, ",
                   name ? name : "unknown", cipher_data[i].nid,
                   cipher_data[i].devcryptoid);
          if (cipher_driver_info[i].status == DEVCRYPTO_STATUS_NO_CIOCGSESSION ) {
              fprintf (stderr, "CIOCGSESSION (session open call) failed\n");
              continue;
          }
          fprintf (stderr, "driver=%s ", cipher_driver_info[i].driver_name ?
                   cipher_driver_info[i].driver_name : "unknown");
          if (cipher_driver_info[i].accelerated == DEVCRYPTO_ACCELERATED)
              fprintf(stderr, "(hw accelerated)");
          else if (cipher_driver_info[i].accelerated == DEVCRYPTO_NOT_ACCELERATED)
              fprintf(stderr, "(software)");
          else
              fprintf(stderr, "(acceleration status unknown)");
          if (cipher_driver_info[i].status == DEVCRYPTO_STATUS_FAILURE)
              fprintf (stderr, ". Cipher setup failed");
          fprintf(stderr, "\n");
      }
      fprintf(stderr, "\n");
  }
  
  /*
   * We only support digests if the cryptodev implementation supports multiple
   * data updates and session copying.  Otherwise, we would be forced to maintain
   * a cache, which is perilous if there's a lot of data coming in (if someone
   * wants to checksum an OpenSSL tarball, for example).
   */
  #if defined(CIOCCPHASH) && defined(COP_FLAG_UPDATE) && defined(COP_FLAG_FINAL)
  #define IMPLEMENT_DIGEST
  
  /******************************************************************************
   *
   * Digests
   *
   * Because they all do the same basic operation, we have only one set of
   * method functions for them all to share, and a mapping table between
   * NIDs and cryptodev IDs, with all the necessary size data.
   *
   *****/
  
  struct digest_ctx {
      struct session_op sess;
      /* This signals that the init function was called, not that it succeeded. */
      int init_called;
      unsigned char digest_res[HASH_MAX_LEN];
  };
  
  static const struct digest_data_st {
      int nid;
      int blocksize;
      int digestlen;
      int devcryptoid;
  } digest_data[] = {
  #ifndef OPENSSL_NO_MD5
      { NID_md5, /* MD5_CBLOCK */ 64, 16, CRYPTO_MD5 },
  #endif
      { NID_sha1, SHA_CBLOCK, 20, CRYPTO_SHA1 },
  #ifndef OPENSSL_NO_RMD160
  # if !defined(CHECK_BSD_STYLE_MACROS) || defined(CRYPTO_RIPEMD160)
      { NID_ripemd160, /* RIPEMD160_CBLOCK */ 64, 20, CRYPTO_RIPEMD160 },
  # endif
  #endif
  #if !defined(CHECK_BSD_STYLE_MACROS) || defined(CRYPTO_SHA2_224)
      { NID_sha224, SHA256_CBLOCK, 224 / 8, CRYPTO_SHA2_224 },
  #endif
  #if !defined(CHECK_BSD_STYLE_MACROS) || defined(CRYPTO_SHA2_256)
      { NID_sha256, SHA256_CBLOCK, 256 / 8, CRYPTO_SHA2_256 },
  #endif
  #if !defined(CHECK_BSD_STYLE_MACROS) || defined(CRYPTO_SHA2_384)
      { NID_sha384, SHA512_CBLOCK, 384 / 8, CRYPTO_SHA2_384 },
  #endif
  #if !defined(CHECK_BSD_STYLE_MACROS) || defined(CRYPTO_SHA2_512)
      { NID_sha512, SHA512_CBLOCK, 512 / 8, CRYPTO_SHA2_512 },
  #endif
  };
  
  static size_t find_digest_data_index(int nid)
  {
      size_t i;
  
      for (i = 0; i < OSSL_NELEM(digest_data); i++)
          if (nid == digest_data[i].nid)
              return i;
      return (size_t)-1;
  }
  
  static size_t get_digest_data_index(int nid)
  {
      size_t i = find_digest_data_index(nid);
  
      if (i != (size_t)-1)
          return i;
  
      /*
       * Code further down must make sure that only NIDs in the table above
       * are used.  If any other NID reaches this function, there's a grave
       * coding error further down.
       */
      assert("Code that never should be reached" == NULL);
      return -1;
  }
  
  static const struct digest_data_st *get_digest_data(int nid)
  {
      return &digest_data[get_digest_data_index(nid)];
  }
  
  /*
   * Following are the five necessary functions to map OpenSSL functionality
   * with cryptodev: init, update, final, cleanup, and copy.
   */
  
  static int digest_init(EVP_MD_CTX *ctx)
  {
      struct digest_ctx *digest_ctx =
          (struct digest_ctx *)EVP_MD_CTX_md_data(ctx);
      const struct digest_data_st *digest_d =
          get_digest_data(EVP_MD_CTX_type(ctx));
  
      digest_ctx->init_called = 1;
  
      memset(&digest_ctx->sess, 0, sizeof(digest_ctx->sess));
      digest_ctx->sess.mac = digest_d->devcryptoid;
      if (ioctl(cfd, CIOCGSESSION, &digest_ctx->sess) < 0) {
          SYSerr(SYS_F_IOCTL, errno);
          return 0;
      }
  
      return 1;
  }
  
  static int digest_op(struct digest_ctx *ctx, const void *src, size_t srclen,
                       void *res, unsigned int flags)
  {
      struct crypt_op cryp;
  
      memset(&cryp, 0, sizeof(cryp));
      cryp.ses = ctx->sess.ses;
      cryp.len = srclen;
      cryp.src = (void *)src;
      cryp.dst = NULL;
      cryp.mac = res;
      cryp.flags = flags;
      return ioctl(cfd, CIOCCRYPT, &cryp);
  }
  
  static int digest_update(EVP_MD_CTX *ctx, const void *data, size_t count)
  {
      struct digest_ctx *digest_ctx =
          (struct digest_ctx *)EVP_MD_CTX_md_data(ctx);
  
      if (count == 0)
          return 1;
  
      if (digest_ctx == NULL)
          return 0;
  
      if (EVP_MD_CTX_test_flags(ctx, EVP_MD_CTX_FLAG_ONESHOT)) {
          if (digest_op(digest_ctx, data, count, digest_ctx->digest_res, 0) >= 0)
              return 1;
      } else if (digest_op(digest_ctx, data, count, NULL, COP_FLAG_UPDATE) >= 0) {
          return 1;
      }
  
      SYSerr(SYS_F_IOCTL, errno);
      return 0;
  }
  
  static int digest_final(EVP_MD_CTX *ctx, unsigned char *md)
  {
      struct digest_ctx *digest_ctx =
          (struct digest_ctx *)EVP_MD_CTX_md_data(ctx);
  
      if (md == NULL || digest_ctx == NULL)
          return 0;
  
      if (EVP_MD_CTX_test_flags(ctx, EVP_MD_CTX_FLAG_ONESHOT)) {
          memcpy(md, digest_ctx->digest_res, EVP_MD_CTX_size(ctx));
      } else if (digest_op(digest_ctx, NULL, 0, md, COP_FLAG_FINAL) < 0) {
          SYSerr(SYS_F_IOCTL, errno);
          return 0;
      }
  
      return 1;
  }
  
  static int digest_copy(EVP_MD_CTX *to, const EVP_MD_CTX *from)
  {
      struct digest_ctx *digest_from =
          (struct digest_ctx *)EVP_MD_CTX_md_data(from);
      struct digest_ctx *digest_to =
          (struct digest_ctx *)EVP_MD_CTX_md_data(to);
      struct cphash_op cphash;
  
      if (digest_from == NULL || digest_from->init_called != 1)
          return 1;
  
      if (!digest_init(to)) {
          SYSerr(SYS_F_IOCTL, errno);
          return 0;
      }
  
      cphash.src_ses = digest_from->sess.ses;
      cphash.dst_ses = digest_to->sess.ses;
      if (ioctl(cfd, CIOCCPHASH, &cphash) < 0) {
          SYSerr(SYS_F_IOCTL, errno);
          return 0;
      }
      return 1;
  }
  
  static int digest_cleanup(EVP_MD_CTX *ctx)
  {
      struct digest_ctx *digest_ctx =
          (struct digest_ctx *)EVP_MD_CTX_md_data(ctx);
  
      if (digest_ctx == NULL)
          return 1;
  
      return clean_devcrypto_session(&digest_ctx->sess);
  }
  
  /*
   * Keep tables of known nids, associated methods, selected digests, and
   * driver info.
   * Note that known_digest_nids[] isn't necessarily indexed the same way as
   * digest_data[] above, which the other tables are.
   */
  static int known_digest_nids[OSSL_NELEM(digest_data)];
  static int known_digest_nids_amount = -1; /* -1 indicates not yet initialised */
  static EVP_MD *known_digest_methods[OSSL_NELEM(digest_data)] = { NULL, };
  static int selected_digests[OSSL_NELEM(digest_data)];
  static struct driver_info_st digest_driver_info[OSSL_NELEM(digest_data)];
  
  static int devcrypto_test_digest(size_t digest_data_index)
  {
      return (digest_driver_info[digest_data_index].status == DEVCRYPTO_STATUS_USABLE
              && selected_digests[digest_data_index] == 1
              && (digest_driver_info[digest_data_index].accelerated
                      == DEVCRYPTO_ACCELERATED
                  || use_softdrivers == DEVCRYPTO_USE_SOFTWARE
                  || (digest_driver_info[digest_data_index].accelerated
                          != DEVCRYPTO_NOT_ACCELERATED
                      && use_softdrivers == DEVCRYPTO_REJECT_SOFTWARE)));
  }
  
  static void rebuild_known_digest_nids(ENGINE *e)
  {
      size_t i;
  
      for (i = 0, known_digest_nids_amount = 0; i < OSSL_NELEM(digest_data); i++) {
          if (devcrypto_test_digest(i))
              known_digest_nids[known_digest_nids_amount++] = digest_data[i].nid;
      }
      ENGINE_unregister_digests(e);
      ENGINE_register_digests(e);
  }
  
  static void prepare_digest_methods(void)
  {
      size_t i;
      struct session_op sess1, sess2;
  #ifdef CIOCGSESSINFO
      struct session_info_op siop;
  #endif
      struct cphash_op cphash;
  
      memset(&digest_driver_info, 0, sizeof(digest_driver_info));
  
      memset(&sess1, 0, sizeof(sess1));
      memset(&sess2, 0, sizeof(sess2));
  
      for (i = 0, known_digest_nids_amount = 0; i < OSSL_NELEM(digest_data);
           i++) {
  
          selected_digests[i] = 1;
  
          /*
           * Check that the digest is usable
           */
          sess1.mac = digest_data[i].devcryptoid;
          sess2.ses = 0;
          if (ioctl(cfd, CIOCGSESSION, &sess1) < 0) {
              digest_driver_info[i].status = DEVCRYPTO_STATUS_NO_CIOCGSESSION;
              goto finish;
          }
  
  #ifdef CIOCGSESSINFO
          /* gather hardware acceleration info from the driver */
          siop.ses = sess1.ses;
          if (ioctl(cfd, CIOCGSESSINFO, &siop) < 0) {
              digest_driver_info[i].accelerated = DEVCRYPTO_ACCELERATION_UNKNOWN;
          } else {
              digest_driver_info[i].driver_name =
                  OPENSSL_strndup(siop.hash_info.cra_driver_name,
                                  CRYPTODEV_MAX_ALG_NAME);
              if (siop.flags & SIOP_FLAG_KERNEL_DRIVER_ONLY)
                  digest_driver_info[i].accelerated = DEVCRYPTO_ACCELERATED;
              else
                  digest_driver_info[i].accelerated = DEVCRYPTO_NOT_ACCELERATED;
          }
  #endif
  
          /* digest must be capable of hash state copy */
          sess2.mac = sess1.mac;
          if (ioctl(cfd, CIOCGSESSION, &sess2) < 0) {
              digest_driver_info[i].status = DEVCRYPTO_STATUS_FAILURE;
              goto finish;
          }
          cphash.src_ses = sess1.ses;
          cphash.dst_ses = sess2.ses;
          if (ioctl(cfd, CIOCCPHASH, &cphash) < 0) {
              digest_driver_info[i].status = DEVCRYPTO_STATUS_NO_CIOCCPHASH;
              goto finish;
          }
          if ((known_digest_methods[i] = EVP_MD_meth_new(digest_data[i].nid,
                                                         NID_undef)) == NULL
              || !EVP_MD_meth_set_input_blocksize(known_digest_methods[i],
                                                  digest_data[i].blocksize)
              || !EVP_MD_meth_set_result_size(known_digest_methods[i],
                                              digest_data[i].digestlen)
              || !EVP_MD_meth_set_init(known_digest_methods[i], digest_init)
              || !EVP_MD_meth_set_update(known_digest_methods[i], digest_update)
              || !EVP_MD_meth_set_final(known_digest_methods[i], digest_final)
              || !EVP_MD_meth_set_copy(known_digest_methods[i], digest_copy)
              || !EVP_MD_meth_set_cleanup(known_digest_methods[i], digest_cleanup)
              || !EVP_MD_meth_set_app_datasize(known_digest_methods[i],
                                               sizeof(struct digest_ctx))) {
              digest_driver_info[i].status = DEVCRYPTO_STATUS_FAILURE;
              EVP_MD_meth_free(known_digest_methods[i]);
              known_digest_methods[i] = NULL;
              goto finish;
          }
          digest_driver_info[i].status = DEVCRYPTO_STATUS_USABLE;
  finish:
          ioctl(cfd, CIOCFSESSION, &sess1.ses);
          if (sess2.ses != 0)
              ioctl(cfd, CIOCFSESSION, &sess2.ses);
          if (devcrypto_test_digest(i))
              known_digest_nids[known_digest_nids_amount++] = digest_data[i].nid;
      }
  }
  
  static const EVP_MD *get_digest_method(int nid)
  {
      size_t i = get_digest_data_index(nid);
  
      if (i == (size_t)-1)
          return NULL;
      return known_digest_methods[i];
  }
  
  static int get_digest_nids(const int **nids)
  {
      *nids = known_digest_nids;
      return known_digest_nids_amount;
  }
  
  static void destroy_digest_method(int nid)
  {
      size_t i = get_digest_data_index(nid);
  
      EVP_MD_meth_free(known_digest_methods[i]);
      known_digest_methods[i] = NULL;
  }
  
  static void destroy_all_digest_methods(void)
  {
      size_t i;
  
      for (i = 0; i < OSSL_NELEM(digest_data); i++) {
          destroy_digest_method(digest_data[i].nid);
          OPENSSL_free(digest_driver_info[i].driver_name);
          digest_driver_info[i].driver_name = NULL;
      }
  }
  
  static int devcrypto_digests(ENGINE *e, const EVP_MD **digest,
                               const int **nids, int nid)
  {
      if (digest == NULL)
          return get_digest_nids(nids);
  
      *digest = get_digest_method(nid);
  
      return *digest != NULL;
  }
  
  static void devcrypto_select_all_digests(int *digest_list)
  {
      size_t i;
  
      for (i = 0; i < OSSL_NELEM(digest_data); i++)
          digest_list[i] = 1;
  }
  
  static int cryptodev_select_digest_cb(const char *str, int len, void *usr)
  {
      int *digest_list = (int *)usr;
      char *name;
      const EVP_MD *EVP;
      size_t i;
  
      if (len == 0)
          return 1;
      if (usr == NULL || (name = OPENSSL_strndup(str, len)) == NULL)
          return 0;
      EVP = EVP_get_digestbyname(name);
      if (EVP == NULL)
          fprintf(stderr, "devcrypto: unknown digest %s\n", name);
      else if ((i = find_digest_data_index(EVP_MD_type(EVP))) != (size_t)-1)
          digest_list[i] = 1;
      else
          fprintf(stderr, "devcrypto: digest %s not available\n", name);
      OPENSSL_free(name);
      return 1;
  }
  
  static void dump_digest_info(void)
  {
      size_t i;
      const char *name;
  
      fprintf (stderr, "Information about digests supported by the /dev/crypto"
               " engine:\n");
  #ifndef CIOCGSESSINFO
      fprintf(stderr, "CIOCGSESSINFO (session info call) unavailable\n");
  #endif
  
      for (i = 0; i < OSSL_NELEM(digest_data); i++) {
          name = OBJ_nid2sn(digest_data[i].nid);
          fprintf (stderr, "Digest %s, NID=%d, /dev/crypto info: id=%d, driver=%s",
                   name ? name : "unknown", digest_data[i].nid,
                   digest_data[i].devcryptoid,
                   digest_driver_info[i].driver_name ? digest_driver_info[i].driver_name : "unknown");
          if (digest_driver_info[i].status == DEVCRYPTO_STATUS_NO_CIOCGSESSION) {
              fprintf (stderr, ". CIOCGSESSION (session open) failed\n");
              continue;
          }
          if (digest_driver_info[i].accelerated == DEVCRYPTO_ACCELERATED)
              fprintf(stderr, " (hw accelerated)");
          else if (digest_driver_info[i].accelerated == DEVCRYPTO_NOT_ACCELERATED)
              fprintf(stderr, " (software)");
          else
              fprintf(stderr, " (acceleration status unknown)");
          if (cipher_driver_info[i].status == DEVCRYPTO_STATUS_FAILURE)
              fprintf (stderr, ". Cipher setup failed\n");
          else if (digest_driver_info[i].status == DEVCRYPTO_STATUS_NO_CIOCCPHASH)
              fprintf(stderr, ", CIOCCPHASH failed\n");
          else
              fprintf(stderr, ", CIOCCPHASH capable\n");
      }
      fprintf(stderr, "\n");
  }
  
  #endif
  
  /******************************************************************************
   *
   * CONTROL COMMANDS
   *
   *****/
  
  #define DEVCRYPTO_CMD_USE_SOFTDRIVERS ENGINE_CMD_BASE
  #define DEVCRYPTO_CMD_CIPHERS (ENGINE_CMD_BASE + 1)
  #define DEVCRYPTO_CMD_DIGESTS (ENGINE_CMD_BASE + 2)
  #define DEVCRYPTO_CMD_DUMP_INFO (ENGINE_CMD_BASE + 3)
  
  #ifndef OPENSSL_MSTR
  # define OPENSSL_MSTR_HELPER(x) #x
  # define OPENSSL_MSTR(x) OPENSSL_MSTR_HELPER(x)
  #endif
  
  static const ENGINE_CMD_DEFN devcrypto_cmds[] = {
  #ifdef CIOCGSESSINFO
     {DEVCRYPTO_CMD_USE_SOFTDRIVERS,
      "USE_SOFTDRIVERS",
      "specifies whether to use software (not accelerated) drivers ("
          OPENSSL_MSTR(DEVCRYPTO_REQUIRE_ACCELERATED) "=use only accelerated drivers, "
          OPENSSL_MSTR(DEVCRYPTO_USE_SOFTWARE) "=allow all drivers, "
          OPENSSL_MSTR(DEVCRYPTO_REJECT_SOFTWARE)
          "=use if acceleration can't be determined) [default="
          OPENSSL_MSTR(DEVCRYPTO_DEFAULT_USE_SOFDTRIVERS) "]",
      ENGINE_CMD_FLAG_NUMERIC},
  #endif
  
     {DEVCRYPTO_CMD_CIPHERS,
      "CIPHERS",
      "either ALL, NONE, or a comma-separated list of ciphers to enable [default=ALL]",
      ENGINE_CMD_FLAG_STRING},
  
  #ifdef IMPLEMENT_DIGEST
     {DEVCRYPTO_CMD_DIGESTS,
      "DIGESTS",
      "either ALL, NONE, or a comma-separated list of digests to enable [default=ALL]",
      ENGINE_CMD_FLAG_STRING},
  #endif
  
     {DEVCRYPTO_CMD_DUMP_INFO,
      "DUMP_INFO",
      "dump info about each algorithm to stderr; use 'openssl engine -pre DUMP_INFO devcrypto'",
      ENGINE_CMD_FLAG_NO_INPUT},
  
     {0, NULL, NULL, 0}
  };
  
  static int devcrypto_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f) (void))
  {
      int *new_list;
      switch (cmd) {
  #ifdef CIOCGSESSINFO
      case DEVCRYPTO_CMD_USE_SOFTDRIVERS:
          switch (i) {
          case DEVCRYPTO_REQUIRE_ACCELERATED:
          case DEVCRYPTO_USE_SOFTWARE:
          case DEVCRYPTO_REJECT_SOFTWARE:
              break;
          default:
              fprintf(stderr, "devcrypto: invalid value (%ld) for USE_SOFTDRIVERS\n", i);
              return 0;
          }
          if (use_softdrivers == i)
              return 1;
          use_softdrivers = i;
  #ifdef IMPLEMENT_DIGEST
          rebuild_known_digest_nids(e);
  #endif
          rebuild_known_cipher_nids(e);
          return 1;
  #endif /* CIOCGSESSINFO */
  
      case DEVCRYPTO_CMD_CIPHERS:
          if (p == NULL)
              return 1;
          if (strcasecmp((const char *)p, "ALL") == 0) {
              devcrypto_select_all_ciphers(selected_ciphers);
          } else if (strcasecmp((const char*)p, "NONE") == 0) {
              memset(selected_ciphers, 0, sizeof(selected_ciphers));
          } else {
              new_list=OPENSSL_zalloc(sizeof(selected_ciphers));
              if (!CONF_parse_list(p, ',', 1, cryptodev_select_cipher_cb, new_list)) {
                  OPENSSL_free(new_list);
                  return 0;
              }
              memcpy(selected_ciphers, new_list, sizeof(selected_ciphers));
              OPENSSL_free(new_list);
          }
          rebuild_known_cipher_nids(e);
          return 1;
  
  #ifdef IMPLEMENT_DIGEST
      case DEVCRYPTO_CMD_DIGESTS:
          if (p == NULL)
              return 1;
          if (strcasecmp((const char *)p, "ALL") == 0) {
              devcrypto_select_all_digests(selected_digests);
          } else if (strcasecmp((const char*)p, "NONE") == 0) {
              memset(selected_digests, 0, sizeof(selected_digests));
          } else {
              new_list=OPENSSL_zalloc(sizeof(selected_digests));
              if (!CONF_parse_list(p, ',', 1, cryptodev_select_digest_cb, new_list)) {
                  OPENSSL_free(new_list);
                  return 0;
              }
              memcpy(selected_digests, new_list, sizeof(selected_digests));
              OPENSSL_free(new_list);
          }
          rebuild_known_digest_nids(e);
          return 1;
  #endif /* IMPLEMENT_DIGEST */
  
      case DEVCRYPTO_CMD_DUMP_INFO:
          dump_cipher_info();
  #ifdef IMPLEMENT_DIGEST
          dump_digest_info();
  #endif
          return 1;
  
      default:
          break;
      }
      return 0;
  }
  
  /******************************************************************************
   *
   * LOAD / UNLOAD
   *
   *****/
  
  static int devcrypto_unload(ENGINE *e)
  {
      destroy_all_cipher_methods();
  #ifdef IMPLEMENT_DIGEST
      destroy_all_digest_methods();
  #endif
  
      close(cfd);
  
      return 1;
  }
  /*
   * This engine is always built into libcrypto, so it doesn't offer any
   * ability to be dynamically loadable.
   */
  void engine_load_devcrypto_int()
  {
      ENGINE *e = NULL;
  
      if ((cfd = open("/dev/crypto", O_RDWR, 0)) < 0) {
  #ifndef ENGINE_DEVCRYPTO_DEBUG
          if (errno != ENOENT)
  #endif
              fprintf(stderr, "Could not open /dev/crypto: %s\n", strerror(errno));
          return;
      }
  
      if ((e = ENGINE_new()) == NULL
          || !ENGINE_set_destroy_function(e, devcrypto_unload)) {
          ENGINE_free(e);
          /*
           * We know that devcrypto_unload() won't be called when one of the
           * above two calls have failed, so we close cfd explicitly here to
           * avoid leaking resources.
           */
          close(cfd);
          return;
      }
  
      prepare_cipher_methods();
  #ifdef IMPLEMENT_DIGEST
      prepare_digest_methods();
  #endif
  
      if (!ENGINE_set_id(e, "devcrypto")
          || !ENGINE_set_name(e, "/dev/crypto engine")
          || !ENGINE_set_cmd_defns(e, devcrypto_cmds)
          || !ENGINE_set_ctrl_function(e, devcrypto_ctrl)
  
  /*
   * Asymmetric ciphers aren't well supported with /dev/crypto.  Among the BSD
   * implementations, it seems to only exist in FreeBSD, and regarding the
   * parameters in its crypt_kop, the manual crypto(4) has this to say:
   *
   *    The semantics of these arguments are currently undocumented.
   *
   * Reading through the FreeBSD source code doesn't give much more than
   * their CRK_MOD_EXP implementation for ubsec.
   *
   * It doesn't look much better with cryptodev-linux.  They have the crypt_kop
   * structure as well as the command (CRK_*) in cryptodev.h, but no support
   * seems to be implemented at all for the moment.
   *
   * At the time of writing, it seems impossible to write proper support for
   * FreeBSD's asym features without some very deep knowledge and access to
   * specific kernel modules.
   *
   * /Richard Levitte, 2017-05-11
   */
  #if 0
  # ifndef OPENSSL_NO_RSA
          || !ENGINE_set_RSA(e, devcrypto_rsa)
  # endif
  # ifndef OPENSSL_NO_DSA
          || !ENGINE_set_DSA(e, devcrypto_dsa)
  # endif
  # ifndef OPENSSL_NO_DH
          || !ENGINE_set_DH(e, devcrypto_dh)
  # endif
  # ifndef OPENSSL_NO_EC
          || !ENGINE_set_EC(e, devcrypto_ec)
  # endif
  #endif
          || !ENGINE_set_ciphers(e, devcrypto_ciphers)
  #ifdef IMPLEMENT_DIGEST
          || !ENGINE_set_digests(e, devcrypto_digests)
  #endif
          ) {
          ENGINE_free(e);
          return;
      }
  
      ENGINE_add(e);
      ENGINE_free(e);          /* Loose our local reference */
      ERR_clear_error();
  }
  