botan_hash.cc

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// Copyright (C) 2014-2024 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 <cryptolink/crypto_hash.h>
 
#include <botan/hash.h>
#include <botan/exceptn.h>
 
#include <cryptolink/botan_common.h>
 
namespace isc {
namespace cryptolink {
 
const std::string
btn::getHashAlgorithmName(HashAlgorithm algorithm) {
    switch (algorithm) {
    case isc::cryptolink::MD5:
        return ("MD5");
    case isc::cryptolink::SHA1:
        return ("SHA-1");
    case isc::cryptolink::SHA256:
        return ("SHA-256");
    case isc::cryptolink::SHA224:
        return ("SHA-224");
    case isc::cryptolink::SHA384:
        return ("SHA-384");
    case isc::cryptolink::SHA512:
        return ("SHA-512");
    case isc::cryptolink::UNKNOWN_HASH:
        return ("Unknown");
    }
    // compiler should have prevented us to reach this, since we have
    // no default. But we need a return value anyway
    return ("Unknown");
}
 
class HashImpl {
public:
 
    explicit HashImpl(const HashAlgorithm hash_algorithm)
    : hash_algorithm_(hash_algorithm), hash_() {
        try {
            const std::string& name =
                btn::getHashAlgorithmName(hash_algorithm);
            hash_ = Botan::HashFunction::create_or_throw(name);
        } catch (const Botan::Lookup_Error&) {
            isc_throw(isc::cryptolink::UnsupportedAlgorithm,
                      "Unknown hash algorithm: " <<
                      static_cast<int>(hash_algorithm));
        } catch (const Botan::Exception& exc) {
            isc_throw(isc::cryptolink::LibraryError,
                      "Botan error: " << exc.what());
        }
    }
 
    ~HashImpl() = default;
 
    HashAlgorithm getHashAlgorithm() const {
        return (hash_algorithm_);
    }
 
    size_t getOutputLength() const {
        return (hash_->output_length());
    }
 
    void update(const void* data, const size_t len) {
        try {
            hash_->update(static_cast<const Botan::byte*>(data), len);
        } catch (const Botan::Exception& exc) {
            isc_throw(isc::cryptolink::LibraryError,
                      "Botan error: " << exc.what());
        }
    }
 
    void final(isc::util::OutputBuffer& result, size_t len) {
        try {
            Botan::secure_vector<Botan::byte> b_result(hash_->final());
 
            if (len > b_result.size()) {
                len = b_result.size();
            }
            result.writeData(&b_result[0], len);
        } catch (const Botan::Exception& exc) {
            isc_throw(isc::cryptolink::LibraryError,
                      "Botan error: " << exc.what());
        }
    }
 
    void final(void* result, size_t len) {
        try {
            Botan::secure_vector<Botan::byte> b_result(hash_->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(isc::cryptolink::LibraryError,
                      "Botan error: " << exc.what());
        }
    }
 
    std::vector<uint8_t> final(size_t len) {
        try {
            Botan::secure_vector<Botan::byte> b_result(hash_->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(isc::cryptolink::LibraryError,
                      "Botan error: " << exc.what());
        }
    }
 
private:
    HashAlgorithm hash_algorithm_;
 
    std::unique_ptr<Botan::HashFunction> hash_;
};
 
Hash::Hash(const HashAlgorithm hash_algorithm)
{
    impl_ = new HashImpl(hash_algorithm);
}
 
Hash::~Hash() {
    delete impl_;
}
 
HashAlgorithm
Hash::getHashAlgorithm() const {
    return (impl_->getHashAlgorithm());
}
 
size_t
Hash::getOutputLength() const {
    return (impl_->getOutputLength());
}
 
void
Hash::update(const void* data, const size_t len) {
    impl_->update(data, len);
}
 
void
Hash::final(isc::util::OutputBuffer& result, size_t len) {
    impl_->final(result, len);
}
 
void
Hash::final(void* result, size_t len) {
    impl_->final(result, len);
}
 
std::vector<uint8_t>
Hash::final(size_t len) {
    return impl_->final(len);
}
 
} // namespace cryptolink
} // namespace isc