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243 | // Copyright (C) 2011-2024 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
#include <config.h>
#include <cryptolink.h><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <cryptolink/crypto_hmac.h>
#include <botan/mac.h><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <botan/exceptn.h><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <cryptolink/botan_common.h>
namespace isc {
namespace cryptolink {
const std::string
btn::getHmacAlgorithmName(HashAlgorithm algorithm) {
switch (algorithm) {
case isc::cryptolink::MD5:
return ("HMAC(MD5)");
case isc::cryptolink::SHA1:
return ("HMAC(SHA-1)");
case isc::cryptolink::SHA256:
return ("HMAC(SHA-256)");
case isc::cryptolink::SHA224:
return ("HMAC(SHA-224)");
case isc::cryptolink::SHA384:
return ("HMAC(SHA-384)");
case isc::cryptolink::SHA512:
return ("HMAC(SHA-512)");
case isc::cryptolink::UNKNOWN_HASH:
return ("HMAC(Unknown)");
}
// compiler should have prevented us to reach this, since we have
// no default. But we need a return value anyway
return ("Unknown");
}
/// @brief Botan implementation of HMAC. Each method is the counterpart
/// of the HMAC corresponding method.
class HMACImpl {
public:
/// @brief Constructor from a secret and a hash algorithm
///
/// See constructor of the @ref isc::cryptolink::HMAC class for details.
///
/// @param secret The secret to sign with
/// @param secret_len The length of the secret
/// @param hash_algorithm The hash algorithm
explicit HMACImpl(const void* secret, size_t secret_len,
const HashAlgorithm hash_algorithm)
: hash_algorithm_(hash_algorithm), hmac_() {
try {
const std::string& name =
btn::getHmacAlgorithmName(hash_algorithm);
hmac_ = Botan::MessageAuthenticationCode::create_or_throw(name);
} catch (const Botan::Lookup_Error&) {
isc_throw(UnsupportedAlgorithm,
"Unknown hash algorithm: " <<
static_cast<int>(hash_algorithm));
} catch (const Botan::Exception& exc) {
isc_throw(LibraryError, "Botan error: " << exc.what());
}
try {
// Botan 1.8 considers len 0 a bad key. 1.9 does not,
// but we won't accept it anyway, and fail early
if (secret_len == 0) {
isc_throw(BadKey, "Bad HMAC secret length: 0");
}
hmac_->set_key(static_cast<const Botan::byte*>(secret),
secret_len);
} catch (const Botan::Invalid_Key_Length& ikl) {
isc_throw(BadKey, ikl.what());
} catch (const Botan::Exception& exc) {
isc_throw(LibraryError, "Botan error: " << exc.what());
}
}
/// @brief Destructor
~HMACImpl() = default;
/// @brief Returns the HashAlgorithm of the object
HashAlgorithm getHashAlgorithm() const {
return (hash_algorithm_);
}
/// @brief Returns the output size of the digest
///
/// @return output size of the digest
size_t getOutputLength() const {
return (hmac_->output_length());
}
/// @brief Add data to digest
///
/// See @ref isc::cryptolink::HMAC::update() for details.
void update(const void* data, const size_t len) {
try {
hmac_->update(static_cast<const Botan::byte*>(data), len);
} catch (const Botan::Exception& exc) {
isc_throw(LibraryError, "Botan error: " << exc.what());
}
}
/// @brief Calculate the final signature
///
/// See @ref isc::cryptolink::HMAC::sign() for details.
void sign(isc::util::OutputBuffer& result, size_t len) {
try {
Botan::secure_vector<Botan::byte> b_result(hmac_->final());
if (len > b_result.size()) {
len = b_result.size();
}
result.writeData(&b_result[0], len);
} catch (const Botan::Exception& exc) {
isc_throw(LibraryError, "Botan error: " << exc.what());
}
}
/// @brief Calculate the final signature
///
/// See @ref isc::cryptolink::HMAC::sign() for details.
void sign(void* result, size_t len) {
try {
Botan::secure_vector<Botan::byte> b_result(hmac_->final());
size_t output_size = getOutputLength();
if (output_size > len) {
output_size = len;
}
std::memcpy(result, &b_result[0], output_size);
} catch (const Botan::Exception& exc) {
isc_throw(LibraryError, "Botan error: " << exc.what());
}
}
/// @brief Calculate the final signature
///
/// See @ref isc::cryptolink::HMAC::sign() for details.
std::vector<uint8_t> sign(size_t len) {
try {
Botan::secure_vector<Botan::byte> b_result(hmac_->final());
if (len > b_result.size()) {
len = b_result.size();
}
// Return vector with content. Construct &b_result[len] attempts
// to get an address of one element beyond the b_result. Replaced
// with the address of first element + len
return (std::vector<uint8_t>(&b_result[0], &b_result[0]+len));
} catch (const Botan::Exception& exc) {
isc_throw(LibraryError, "Botan error: " << exc.what());
}
}
/// @brief Verify an existing signature
///
/// See @ref isc::cryptolink::HMAC::verify() for details.
bool verify(const void* sig, size_t len) {
// Botan's verify_mac checks if len matches the output_length,
// which causes it to fail for truncated signatures, so we do
// the check ourselves
try {
size_t size = getOutputLength();
if (len < 10 || len < size / 2) {
return (false);
}
if (len > size) {
len = size;
}
if (digest_.size() == 0) {
digest_ = hmac_->final();
}
const uint8_t* sig8 = static_cast<const uint8_t*>(sig);
return (Botan::constant_time_compare(&digest_[0], sig8, len));
} catch (const Botan::Exception& exc) {
isc_throw(LibraryError, "Botan error: " << exc.what());
}
}
private:
/// @brief The hash algorithm
HashAlgorithm hash_algorithm_;
/// @brief The protected pointer to the Botan HMAC object
std::unique_ptr<Botan::MessageAuthenticationCode> hmac_;
/// @brief The digest cache for multiple verify
Botan::secure_vector<Botan::byte> digest_;
};
HMAC::HMAC(const void* secret, size_t secret_length,
const HashAlgorithm hash_algorithm)
{
impl_ = new HMACImpl(secret, secret_length, hash_algorithm);
}
HMAC::~HMAC() {
delete impl_;
}
HashAlgorithm
HMAC::getHashAlgorithm() const {
return (impl_->getHashAlgorithm());
}
size_t
HMAC::getOutputLength() const {
return (impl_->getOutputLength());
}
void
HMAC::update(const void* data, const size_t len) {
impl_->update(data, len);
}
void
HMAC::sign(isc::util::OutputBuffer& result, size_t len) {
impl_->sign(result, len);
}
void
HMAC::sign(void* result, size_t len) {
impl_->sign(result, len);
}
std::vector<uint8_t>
HMAC::sign(size_t len) {
return impl_->sign(len);
}
bool
HMAC::verify(const void* sig, const size_t len) {
return (impl_->verify(sig, len));
}
} // namespace cryptolink
} // namespace isc
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