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/*
* Cipher Modes via CommonCrypto
* (C) 2018 Jose Pereira
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/internal/commoncrypto.h>
#include <botan/internal/commoncrypto_utils.h>
#include <botan/cipher_mode.h>
#include <botan/internal/rounding.h>
#include <limits.h>
namespace Botan {
namespace {
class CommonCrypto_Cipher_Mode final : public Cipher_Mode
{
public:
CommonCrypto_Cipher_Mode(const std::string& name,
Cipher_Dir direction,
const CommonCryptor_Opts& opts);
~CommonCrypto_Cipher_Mode();
std::string provider() const override { return "commoncrypto"; }
std::string name() const override { return m_mode_name; }
void start_msg(const uint8_t nonce[], size_t nonce_len) override;
size_t process(uint8_t msg[], size_t msg_len) override;
void finish(secure_vector<uint8_t>& final_block, size_t offset0) override;
size_t output_length(size_t input_length) const override;
size_t update_granularity() const override;
size_t minimum_final_size() const override;
size_t default_nonce_length() const override;
bool valid_nonce_length(size_t nonce_len) const override;
void clear() override;
void reset() override;
Key_Length_Specification key_spec() const override;
private:
void key_schedule(const uint8_t key[], size_t length) override;
const std::string m_mode_name;
Cipher_Dir m_direction;
CommonCryptor_Opts m_opts;
CCCryptorRef m_cipher = nullptr;
bool m_key_set;
bool m_nonce_set;
};
CommonCrypto_Cipher_Mode::CommonCrypto_Cipher_Mode(const std::string& name,
Cipher_Dir direction, const CommonCryptor_Opts& opts) :
m_mode_name(name),
m_direction(direction),
m_opts(opts),
m_key_set(false),
m_nonce_set(false)
{
}
CommonCrypto_Cipher_Mode::~CommonCrypto_Cipher_Mode()
{
if(m_cipher)
{
CCCryptorRelease(m_cipher);
}
}
void CommonCrypto_Cipher_Mode::start_msg(const uint8_t nonce[], size_t nonce_len)
{
verify_key_set(m_key_set);
if(!valid_nonce_length(nonce_len))
{ throw Invalid_IV_Length(name(), nonce_len); }
if(nonce_len)
{
CCCryptorStatus status = CCCryptorReset(m_cipher, nonce);
if(status != kCCSuccess)
{
throw CommonCrypto_Error("CCCryptorReset on start_msg", status);
}
}
m_nonce_set = true;
}
size_t CommonCrypto_Cipher_Mode::process(uint8_t msg[], size_t msg_len)
{
verify_key_set(m_key_set);
BOTAN_STATE_CHECK(m_nonce_set);
if(msg_len == 0)
{ return 0; }
if(msg_len > INT_MAX)
{ throw Internal_Error("msg_len overflow"); }
size_t outl = CCCryptorGetOutputLength(m_cipher, msg_len, false);
secure_vector<uint8_t> out(outl);
if(m_opts.padding == ccNoPadding && msg_len % m_opts.block_size)
{
msg_len = outl;
}
CCCryptorStatus status = CCCryptorUpdate(m_cipher, msg, msg_len,
out.data(), outl, &outl);
if(status != kCCSuccess)
{
throw CommonCrypto_Error("CCCryptorUpdate", status);
}
copy_mem(msg, out.data(), outl);
return outl;
}
void CommonCrypto_Cipher_Mode::finish(secure_vector<uint8_t>& buffer,
size_t offset)
{
verify_key_set(m_key_set);
BOTAN_STATE_CHECK(m_nonce_set);
BOTAN_ASSERT(buffer.size() >= offset, "Offset ok");
uint8_t* buf = buffer.data() + offset;
const size_t buf_size = buffer.size() - offset;
size_t written = process(buf, buf_size);
size_t outl = CCCryptorGetOutputLength(m_cipher, buf_size - written, true);
secure_vector<uint8_t> out(outl);
CCCryptorStatus status = CCCryptorFinal(
m_cipher, out.data(), outl, &outl);
if(status != kCCSuccess)
{
throw CommonCrypto_Error("CCCryptorFinal", status);
}
size_t new_len = offset + written + outl;
if(m_opts.padding != ccNoPadding || buffer.size() < new_len)
{
buffer.resize(new_len);
}
copy_mem(buffer.data() - offset + written, out.data(), outl);
written += outl;
}
size_t CommonCrypto_Cipher_Mode::update_granularity() const
{
return m_opts.block_size * BOTAN_BLOCK_CIPHER_PAR_MULT;
}
size_t CommonCrypto_Cipher_Mode::minimum_final_size() const
{
if(m_direction == ENCRYPTION)
return 0;
else
return m_opts.block_size;
}
size_t CommonCrypto_Cipher_Mode::default_nonce_length() const
{
return m_opts.block_size;
}
bool CommonCrypto_Cipher_Mode::valid_nonce_length(size_t nonce_len) const
{
return (nonce_len == 0 || nonce_len == m_opts.block_size);
}
size_t CommonCrypto_Cipher_Mode::output_length(size_t input_length) const
{
if(input_length == 0)
{ return m_opts.block_size; }
else
{ return round_up(input_length, m_opts.block_size); }
}
void CommonCrypto_Cipher_Mode::clear()
{
m_key_set = false;
if(m_cipher == nullptr)
{
return;
}
if(m_cipher)
{
CCCryptorRelease(m_cipher);
m_cipher = nullptr;
}
}
void CommonCrypto_Cipher_Mode::reset()
{
if(m_cipher == nullptr)
{
return;
}
m_nonce_set = false;
CCCryptorStatus status = CCCryptorReset(m_cipher, nullptr);
if(status != kCCSuccess)
{
throw CommonCrypto_Error("CCCryptorReset", status);
}
}
Key_Length_Specification CommonCrypto_Cipher_Mode::key_spec() const
{
return m_opts.key_spec;
}
void CommonCrypto_Cipher_Mode::key_schedule(const uint8_t key[], size_t length)
{
CCCryptorStatus status;
CCOperation op = m_direction == ENCRYPTION ? kCCEncrypt : kCCDecrypt;
status = CCCryptorCreateWithMode(op, m_opts.mode, m_opts.algo, m_opts.padding,
nullptr, key, length, nullptr, 0, 0, 0, &m_cipher);
if(status != kCCSuccess)
{
throw CommonCrypto_Error("CCCryptorCreate", status);
}
m_key_set = true;
m_nonce_set = false;
}
}
Cipher_Mode*
make_commoncrypto_cipher_mode(const std::string& name, Cipher_Dir direction)
{
try
{
CommonCryptor_Opts opts = commoncrypto_opts_from_algo(name);
return new CommonCrypto_Cipher_Mode(name, direction, opts);
}
catch(CommonCrypto_Error& e)
{
return nullptr;
}
}
}
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