transmission/libtransmission/crypto-utils-ccrypto.cc

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// This file Copyright © 2021-2022 Mnemosyne LLC.
// It may be used under GPLv2 (SPDX: GPL-2.0), GPLv3 (SPDX: GPL-3.0),
// or any future license endorsed by Mnemosyne LLC.
// License text can be found in the licenses/ folder.
#include <memory>
#include <type_traits>
#ifdef HAVE_COMMONCRYPTO_COMMONBIGNUM_H
#include <CommonCrypto/CommonBigNum.h>
#endif
#include <CommonCrypto/CommonDigest.h>
#include <CommonCrypto/CommonRandom.h>
#include "transmission.h"
#include "crypto-utils.h"
#include "log.h"
#include "tr-assert.h"
#include "utils.h"
#define TR_CRYPTO_DH_SECRET_FALLBACK
#define TR_CRYPTO_X509_FALLBACK
#include "crypto-utils-fallback.cc"
/***
****
***/
#ifndef HAVE_COMMONCRYPTO_COMMONBIGNUM_H
using CCBigNumRef = struct _CCBigNumRef*;
using CCBigNumConstRef = struct _CCBigNumRef const*;
using CCStatus = CCCryptorStatus;
extern "C"
{
CCBigNumRef CCBigNumFromData(CCStatus* status, void const* s, size_t len);
CCBigNumRef CCCreateBigNum(CCStatus* status);
CCBigNumRef CCBigNumCreateRandom(CCStatus* status, int bits, int top, int bottom);
void CCBigNumFree(CCBigNumRef bn);
CCStatus CCBigNumModExp(CCBigNumRef result, CCBigNumConstRef a, CCBigNumConstRef power, CCBigNumConstRef modulus);
uint32_t CCBigNumByteCount(CCBigNumConstRef bn);
size_t CCBigNumToData(CCStatus* status, CCBigNumConstRef bn, void* to);
}
#endif /* !HAVE_COMMONCRYPTO_COMMONBIGNUM_H */
/***
****
***/
namespace
{
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static char constexpr MyName[] = "tr_crypto_utils";
char const* ccrypto_error_to_str(CCCryptorStatus error_code)
{
switch (error_code)
{
case kCCSuccess:
return "Operation completed normally";
case kCCParamError:
return "Illegal parameter value";
case kCCBufferTooSmall:
return "Insufficent buffer provided for specified operation";
case kCCMemoryFailure:
return "Memory allocation failure";
case kCCAlignmentError:
return "Input size was not aligned properly";
case kCCDecodeError:
return "Input data did not decode or decrypt properly";
case kCCUnimplemented:
return "Function not implemented for the current algorithm";
case kCCOverflow:
return "Buffer overflow";
case kCCRNGFailure:
return "Random number generator failure";
}
return "Unknown error";
}
void log_ccrypto_error(CCCryptorStatus error_code, char const* file, int line)
{
if (tr_logLevelIsActive(TR_LOG_ERROR))
{
tr_logAddMessage(
file,
line,
TR_LOG_ERROR,
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MyName,
"CCrypto error (%d): %s",
error_code,
ccrypto_error_to_str(error_code));
}
}
bool check_ccrypto_result(CCCryptorStatus result, char const* file, int line)
{
bool const ret = result == kCCSuccess;
if (!ret)
{
log_ccrypto_error(result, file, line);
}
return ret;
}
#define check_result(result) check_ccrypto_result((result), __FILE__, __LINE__)
bool check_ccrypto_pointer(void const* pointer, CCCryptorStatus const* result, char const* file, int line)
{
bool const ret = pointer != nullptr;
if (!ret)
{
log_ccrypto_error(*result, file, line);
}
return ret;
}
#define check_pointer(pointer, result) check_ccrypto_pointer((pointer), (result), __FILE__, __LINE__)
} // namespace
/***
****
***/
tr_sha1_ctx_t tr_sha1_init(void)
{
auto* handle = new CC_SHA1_CTX();
CC_SHA1_Init(handle);
return handle;
}
bool tr_sha1_update(tr_sha1_ctx_t handle, void const* data, size_t data_length)
{
TR_ASSERT(handle != nullptr);
if (data_length == 0)
{
return true;
}
TR_ASSERT(data != nullptr);
CC_SHA1_Update(static_cast<CC_SHA1_CTX*>(handle), data, data_length);
return true;
}
std::optional<tr_sha1_digest_t> tr_sha1_final(tr_sha1_ctx_t raw_handle)
{
TR_ASSERT(raw_handle != nullptr);
auto* handle = static_cast<CC_SHA1_CTX*>(raw_handle);
auto digest = tr_sha1_digest_t{};
auto* const digest_as_uchar = reinterpret_cast<unsigned char*>(std::data(digest));
CC_SHA1_Final(digest_as_uchar, handle);
delete handle;
return digest;
}
/***
****
***/
namespace
{
struct CCBigNumDeleter
{
void operator()(CCBigNumRef bn) const noexcept
{
if (bn != nullptr)
{
CCBigNumFree(bn);
}
}
};
using CCBigNumPtr = std::unique_ptr<std::remove_pointer_t<CCBigNumRef>, CCBigNumDeleter>;
struct tr_dh_ctx
{
CCBigNumPtr p;
CCBigNumPtr g;
CCBigNumPtr private_key;
};
} // namespace
tr_dh_ctx_t tr_dh_new(
uint8_t const* prime_num,
size_t prime_num_length,
uint8_t const* generator_num,
size_t generator_num_length)
{
TR_ASSERT(prime_num != nullptr);
TR_ASSERT(generator_num != nullptr);
auto handle = std::make_unique<tr_dh_ctx>();
auto status = CCStatus{};
handle->p = CCBigNumPtr(CCBigNumFromData(&status, prime_num, prime_num_length));
if (!check_pointer(handle->p.get(), &status))
{
return nullptr;
}
handle->g = CCBigNumPtr(CCBigNumFromData(&status, generator_num, generator_num_length));
if (!check_pointer(handle->g.get(), &status))
{
return nullptr;
}
return handle.release();
}
void tr_dh_free(tr_dh_ctx_t handle)
{
delete static_cast<tr_dh_ctx*>(handle);
}
bool tr_dh_make_key(tr_dh_ctx_t raw_handle, size_t private_key_length, uint8_t* public_key, size_t* public_key_length)
{
TR_ASSERT(raw_handle != nullptr);
TR_ASSERT(public_key != nullptr);
auto& handle = *static_cast<tr_dh_ctx*>(raw_handle);
auto status = CCStatus{};
handle.private_key = CCBigNumPtr(CCBigNumCreateRandom(&status, private_key_length * 8, private_key_length * 8, 0));
if (!check_pointer(handle.private_key.get(), &status))
{
return false;
}
auto const my_public_key = CCBigNumPtr(CCCreateBigNum(&status));
if (!check_pointer(my_public_key.get(), &status))
{
return false;
}
if (!check_result(CCBigNumModExp(my_public_key.get(), handle.g.get(), handle.private_key.get(), handle.p.get())))
{
return false;
}
auto const my_public_key_length = CCBigNumByteCount(my_public_key.get());
CCBigNumToData(&status, my_public_key.get(), public_key);
if (!check_result(status))
{
return false;
}
auto const dh_size = CCBigNumByteCount(handle.p.get());
tr_dh_align_key(public_key, my_public_key_length, dh_size);
if (public_key_length != nullptr)
{
*public_key_length = dh_size;
}
return true;
}
tr_dh_secret_t tr_dh_agree(tr_dh_ctx_t raw_handle, uint8_t const* other_public_key, size_t other_public_key_length)
{
TR_ASSERT(raw_handle != nullptr);
TR_ASSERT(other_public_key != nullptr);
auto const& handle = *static_cast<tr_dh_ctx*>(raw_handle);
auto status = CCStatus{};
auto const other_key = CCBigNumPtr(CCBigNumFromData(&status, other_public_key, other_public_key_length));
if (!check_pointer(other_key.get(), &status))
{
return nullptr;
}
auto const my_secret_key = CCBigNumPtr(CCCreateBigNum(&status));
if (!check_pointer(my_secret_key.get(), &status))
{
return nullptr;
}
if (!check_result(CCBigNumModExp(my_secret_key.get(), other_key.get(), handle.private_key.get(), handle.p.get())))
{
return nullptr;
}
auto const dh_size = CCBigNumByteCount(handle.p.get());
auto ret = std::unique_ptr<tr_dh_secret, decltype(&tr_free)>(tr_dh_secret_new(dh_size), &tr_free);
auto const my_secret_key_length = CCBigNumByteCount(my_secret_key.get());
CCBigNumToData(&status, my_secret_key.get(), ret->key);
if (!check_result(status))
{
return nullptr;
}
tr_dh_secret_align(ret.get(), my_secret_key_length);
return ret.release();
}
/***
****
***/
bool tr_rand_buffer(void* buffer, size_t length)
{
if (length == 0)
{
return true;
}
TR_ASSERT(buffer != nullptr);
return check_result(CCRandomGenerateBytes(buffer, length));
}