openssl_hash.cc

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// Copyright (C) 2014-2017 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 <boost/scoped_ptr.hpp>
 
#include <openssl/evp.h>
 
#include <cryptolink/openssl_common.h>
#define KEA_HASH
#include <cryptolink/openssl_compat.h>
 
#include <cstring>
 
namespace isc {
namespace cryptolink {
 
const EVP_MD*
ossl::getHashAlgorithm(HashAlgorithm algorithm) {
    switch (algorithm) {
    case isc::cryptolink::MD5:
        return (EVP_md5());
    case isc::cryptolink::SHA1:
        return (EVP_sha1());
    case isc::cryptolink::SHA256:
        return (EVP_sha256());
    case isc::cryptolink::SHA224:
        return (EVP_sha224());
    case isc::cryptolink::SHA384:
        return (EVP_sha384());
    case isc::cryptolink::SHA512:
        return (EVP_sha512());
    case isc::cryptolink::UNKNOWN_HASH:
        return (0);
    }
    // compiler should have prevented us to reach this, since we have
    // no default. But we need a return value anyway
    return (0);
}
 
class HashImpl {
public:
 
    explicit HashImpl(const HashAlgorithm hash_algorithm)
    : hash_algorithm_(hash_algorithm), md_(0) {
        const EVP_MD* algo = ossl::getHashAlgorithm(hash_algorithm);
        if (algo == 0) {
            isc_throw(isc::cryptolink::UnsupportedAlgorithm,
                      "Unknown hash algorithm: " <<
                      static_cast<int>(hash_algorithm));
        }
 
        md_ = EVP_MD_CTX_new();
        if (md_ == 0) {
            isc_throw(isc::cryptolink::LibraryError,
                      "OpenSSL EVP_MD_CTX_new() failed");
        }
 
        EVP_DigestInit_ex(md_, algo, NULL);
    }
 
    ~HashImpl() {
        if (md_) {
            EVP_MD_CTX_free(md_);
        }
        md_ = 0;
    }
 
    HashAlgorithm getHashAlgorithm() const {
        return (hash_algorithm_);
    }
 
    size_t getOutputLength() const {
        return (EVP_MD_CTX_size(md_));
    }
 
    void update(const void* data, const size_t len) {
        EVP_DigestUpdate(md_, data, len);
    }
 
    void final(isc::util::OutputBuffer& result, size_t len) {
        size_t size = getOutputLength();
        std::vector<unsigned char> digest(size);
        EVP_DigestFinal_ex(md_, &digest[0], NULL);
        if (len > size) {
             len = size;
        }
        result.writeData(&digest[0], len);
    }
 
    void final(void* result, size_t len) {
        size_t size = getOutputLength();
        std::vector<unsigned char> digest(size);
        EVP_DigestFinal_ex(md_, &digest[0], NULL);
        if (len > size) {
             len = size;
        }
        std::memcpy(result, &digest[0], len);
    }
 
    std::vector<uint8_t> final(size_t len) {
        size_t size = getOutputLength();
        std::vector<unsigned char> digest(size);
        EVP_DigestFinal_ex(md_, &digest[0], NULL);
        if (len < size) {
            digest.resize(len);
        }
        return (std::vector<uint8_t>(digest.begin(), digest.end()));
    }
 
private:
    HashAlgorithm hash_algorithm_;
 
    EVP_MD_CTX* md_;
};
 
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