First Commit

src/common/Cryptography/HMAC.h

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+/*
+ * This file is part of the AzerothCore Project. See AUTHORS file for Copyright information
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Affero General Public License as published by the
+ * Free Software Foundation; either version 3 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef AZEROTHCORE_HMAC_H
+#define AZEROTHCORE_HMAC_H
+
+#include "CryptoConstants.h"
+#include "CryptoHash.h"
+#include "Errors.h"
+#include <array>
+#include <string>
+#include <string_view>
+
+class BigNumber;
+
+namespace Acore::Impl
+{
+    template <GenericHashImpl::HashCreator HashCreator, std::size_t DigestLength>
+    class GenericHMAC
+    {
+        public:
+            static constexpr std::size_t DIGEST_LENGTH = DigestLength;
+            using Digest = std::array<uint8, DIGEST_LENGTH>;
+
+            template <typename Container>
+            static Digest GetDigestOf(Container const& seed, uint8 const* data, std::size_t len)
+            {
+                GenericHMAC hash(seed);
+                hash.UpdateData(data, len);
+                hash.Finalize();
+                return hash.GetDigest();
+            }
+
+            template <typename Container, typename... Ts>
+            static auto GetDigestOf(Container const& seed, Ts&&... pack) -> std::enable_if_t<!(std::is_integral_v<std::decay_t<Ts>> || ...), Digest>
+            {
+                GenericHMAC hash(seed);
+                (hash.UpdateData(std::forward<Ts>(pack)), ...);
+                hash.Finalize();
+                return hash.GetDigest();
+            }
+
+            GenericHMAC(uint8 const* seed, std::size_t len) : _ctx(GenericHashImpl::MakeCTX()), _key(EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, nullptr, seed, len))
+            {
+                int result = EVP_DigestSignInit(_ctx, nullptr, HashCreator(), nullptr, _key);
+                ASSERT(result == 1);
+            }
+
+            template <typename Container>
+            GenericHMAC(Container const& container) : GenericHMAC(std::data(container), std::size(container)) {}
+
+            GenericHMAC(GenericHMAC const& right) : _ctx(GenericHashImpl::MakeCTX())
+            {
+                *this = right;
+            }
+
+            GenericHMAC(GenericHMAC&& right) noexcept
+            {
+                *this = std::move(right);
+            }
+
+            ~GenericHMAC()
+            {
+                GenericHashImpl::DestroyCTX(_ctx);
+                _ctx = nullptr;
+                EVP_PKEY_free(_key);
+                _key = nullptr;
+            }
+
+            GenericHMAC& operator=(GenericHMAC const& right)
+            {
+                if (this == &right)
+                    return *this;
+
+                int result = EVP_MD_CTX_copy_ex(_ctx, right._ctx);
+                ASSERT(result == 1);
+                _key = right._key;      // EVP_PKEY uses reference counting internally, just copy the pointer
+                EVP_PKEY_up_ref(_key);  // Bump reference count for PKEY, as every instance of this class holds two references to PKEY and destructor decrements it twice
+                _digest = right._digest;
+                return *this;
+            }
+
+            GenericHMAC& operator=(GenericHMAC&& right) noexcept
+            {
+                if (this == &right)
+                    return *this;
+
+                _ctx = std::exchange(right._ctx, GenericHashImpl::MakeCTX());
+                _key = std::exchange(right._key, EVP_PKEY_new());
+                _digest = std::exchange(right._digest, Digest{});
+                return *this;
+            }
+
+            void UpdateData(uint8 const* data, std::size_t len)
+            {
+                int result = EVP_DigestSignUpdate(_ctx, data, len);
+                ASSERT(result == 1);
+            }
+
+            void UpdateData(std::string_view str) { UpdateData(reinterpret_cast<uint8 const*>(str.data()), str.size()); }
+            void UpdateData(std::string const& str) { UpdateData(std::string_view(str)); } /* explicit overload to avoid using the container template */
+            void UpdateData(char const* str) { UpdateData(std::string_view(str)); } /* explicit overload to avoid using the container template */
+
+            template <typename Container>
+            void UpdateData(Container const& c) { UpdateData(std::data(c), std::size(c)); }
+
+            void Finalize()
+            {
+                std::size_t length = DIGEST_LENGTH;
+                int result = EVP_DigestSignFinal(_ctx, _digest.data(), &length);
+                ASSERT(result == 1);
+                ASSERT(length == DIGEST_LENGTH);
+            }
+
+            Digest const& GetDigest() const { return _digest; }
+        private:
+            EVP_MD_CTX* _ctx{};
+            EVP_PKEY* _key{};
+            Digest _digest{};
+    };
+}
+
+namespace Acore::Crypto
+{
+    using HMAC_SHA1 = Acore::Impl::GenericHMAC<EVP_sha1, Constants::SHA1_DIGEST_LENGTH_BYTES>;
+    using HMAC_SHA256 = Acore::Impl::GenericHMAC<EVP_sha256, Constants::SHA256_DIGEST_LENGTH_BYTES>;
+}
+
+#endif