commoncrypto_block.cpp

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/*
* Block Ciphers via CommonCrypto
* (C) 2018 Jose Luis Pereira
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
 
#include <botan/internal/commoncrypto.h>
 
#include <botan/block_cipher.h>
#include <botan/hex.h>
#include <botan/internal/commoncrypto_utils.h>
 
#include <CommonCrypto/CommonCrypto.h>
 
namespace Botan {
 
namespace {
 
class CommonCrypto_BlockCipher final : public BlockCipher {
   public:
      CommonCrypto_BlockCipher(std::string_view name, const CommonCryptor_Opts& opts);
 
      ~CommonCrypto_BlockCipher();
 
      void clear() override;
 
      std::string provider() const override { return "commoncrypto"; }
 
      std::string name() const override { return m_cipher_name; }
 
      std::unique_ptr<BlockCipher> new_object() const override;
 
      size_t block_size() const override { return m_opts.block_size; }
 
      Key_Length_Specification key_spec() const override { return m_opts.key_spec; }
 
      bool has_keying_material() const override { return m_key_set; }
 
      void encrypt_n(const uint8_t in[], uint8_t out[], size_t blocks) const override {
         assert_key_material_set();
         size_t total_len = blocks * m_opts.block_size;
         size_t out_len = 0;
 
         CCCryptorStatus status = CCCryptorUpdate(m_encrypt, in, total_len, out, total_len, &out_len);
         if(status != kCCSuccess) {
            throw CommonCrypto_Error("CCCryptorUpdate encrypt", status);
         }
      }
 
      void decrypt_n(const uint8_t in[], uint8_t out[], size_t blocks) const override {
         assert_key_material_set();
         size_t total_len = blocks * m_opts.block_size;
         size_t out_len = 0;
 
         CCCryptorStatus status = CCCryptorUpdate(m_decrypt, in, total_len, out, total_len, &out_len);
         if(status != kCCSuccess) {
            throw CommonCrypto_Error("CCCryptorUpdate decrypt", status);
         }
      }
 
      void key_schedule(std::span<const uint8_t> key) override;
 
      std::string m_cipher_name;
      CommonCryptor_Opts m_opts;
 
      CCCryptorRef m_encrypt = nullptr;
      CCCryptorRef m_decrypt = nullptr;
      bool m_key_set;
};
 
CommonCrypto_BlockCipher::CommonCrypto_BlockCipher(std::string_view algo_name, const CommonCryptor_Opts& opts) :
      m_cipher_name(algo_name), m_opts(opts), m_key_set(false) {}
 
CommonCrypto_BlockCipher::~CommonCrypto_BlockCipher() {
   if(m_encrypt) {
      CCCryptorRelease(m_encrypt);
   }
   if(m_decrypt) {
      CCCryptorRelease(m_decrypt);
   }
}
 
/*
* Set the key
*/
void CommonCrypto_BlockCipher::key_schedule(std::span<const uint8_t> key) {
   secure_vector<uint8_t> full_key(key.begin(), key.end());
 
   clear();
   commoncrypto_adjust_key_size(key.data(), key.size(), m_opts, full_key);
 
   CCCryptorStatus status;
   status =
      CCCryptorCreate(kCCEncrypt, m_opts.algo, kCCOptionECBMode, full_key.data(), full_key.size(), nullptr, &m_encrypt);
   if(status != kCCSuccess) {
      throw CommonCrypto_Error("CCCryptorCreate encrypt", status);
   }
   status =
      CCCryptorCreate(kCCDecrypt, m_opts.algo, kCCOptionECBMode, full_key.data(), full_key.size(), nullptr, &m_decrypt);
   if(status != kCCSuccess) {
      throw CommonCrypto_Error("CCCryptorCreate decrypt", status);
   }
 
   m_key_set = true;
}
 
/*
* Return a clone of this object
*/
std::unique_ptr<BlockCipher> CommonCrypto_BlockCipher::new_object() const {
   return std::make_unique<CommonCrypto_BlockCipher>(m_cipher_name, m_opts);
}
 
/*
* Clear memory of sensitive data
*/
void CommonCrypto_BlockCipher::clear() {
   m_key_set = false;
 
   if(m_encrypt) {
      CCCryptorRelease(m_encrypt);
      m_encrypt = nullptr;
   }
 
   if(m_decrypt) {
      CCCryptorRelease(m_decrypt);
      m_decrypt = nullptr;
   }
}
}  // namespace
 
std::unique_ptr<BlockCipher> make_commoncrypto_block_cipher(std::string_view name) {
   try {
      CommonCryptor_Opts opts = commoncrypto_opts_from_algo_name(name);
      return std::make_unique<CommonCrypto_BlockCipher>(name, opts);
   } catch(CommonCrypto_Error& e) {
      return nullptr;
   }
}
}  // namespace Botan