1 files changed, 125 insertions, 13 deletions

diff --git a/include/modules/encryption.h b/include/modules/encryption.h
index 7162ef255..c475f4fbd 100644
--- a/include/modules/encryption.h
+++ b/include/modules/encryption.h
@@ -9,27 +9,139 @@
  * Based on the original code of Services by Andy Church.
  */
 
+#pragma once
+
 namespace Encryption
 {
-	typedef std::pair<const unsigned char *, size_t> Hash;
-	typedef std::pair<const uint32_t *, size_t> IV;
-
+	/** Base class for encryption contexts. */
 	class Context
 	{
-	 public:
-		virtual ~Context() { }
+	public:
+		virtual ~Context() = default;
+
+		/** Updates the encryption context with the specified data.
+		 * @param str The data to update the context with.
+		 */
+		inline void Update(const Anope::string &str)
+		{
+			Update(reinterpret_cast<const unsigned char *>(str.c_str()), str.length());
+		}
+
+		/** Updates the encryption context with the specified data.
+		 * @param data The data to update the context with.
+		 * @param len The length of the data.
+		 */
 		virtual void Update(const unsigned char *data, size_t len) = 0;
-		virtual void Finalize() = 0;
-		virtual Hash GetFinalizedHash() = 0;
+
+		/** Finalises the encryption context and returns the digest. */
+		virtual Anope::string Finalize() = 0;
+	};
+
+	/** Provider of encryption contexts. */
+	class Provider
+		: public Service
+	{
+	public:
+		/** The byte size of the block cipher. */
+		const size_t block_size;
+
+		/** The byte size of the resulting digest. */
+		const size_t digest_size;
+
+		/** Creates a provider of encryption contexts.
+		 * @param creator The module that created this provider.
+		 * @param algorithm The name of the encryption algorithm.
+		 * @param bs The byte size of the block cipher.
+		 * @param ds The byte size of the resulting digest.
+		 */
+		Provider(Module *creator, const Anope::string &algorithm, size_t bs, size_t ds)
+			: Service(creator, "Encryption::Provider", algorithm)
+			, block_size(bs)
+			, digest_size(ds)
+		{
+		}
+
+		virtual ~Provider() = default;
+
+		/** Checks whether a plain text value matches a hash created by this provider. */
+		virtual bool Compare(const Anope::string &hash, const Anope::string &plain)
+		{
+			return !hash.empty() && hash.equals_cs(ToPrintable(Encrypt(plain)));
+		}
+
+		/** Called on initialising a encryption provider to check it works properly. */
+		void Check(const Anope::map<Anope::string> &checks)
+		{
+			for (const auto &[hash, plain] : checks)
+			{
+				if (!Compare(hash, plain))
+					throw ModuleException("BUG: unable to generate " + this->name + " hashes safely! Please report this!");
+			}
+			Log(LOG_DEBUG) << "The " << this->name << " encryption provider appears to be working correctly.";
+		}
+
+		/** Creates a new encryption context. */
+		virtual std::unique_ptr<Context> CreateContext() = 0;
+
+		/** Quickly encrypts the specified values and returns the digest. */
+		template<typename... Args>
+		Anope::string Encrypt(Args &&...args)
+		{
+			auto context = CreateContext();
+			context->Update(std::forward<Args>(args)...);
+			return context->Finalize();
+		}
+
+		/** Calculates the  RFC 2104 hash-based message authentication code for the specified data. */
+		inline Anope::string HMAC(const Anope::string &key, const Anope::string &data)
+		{
+			if (!block_size)
+				return {};
+
+			auto keybuf = key.length() > block_size ? Encrypt(key) : key;
+			keybuf.resize(block_size);
+
+			Anope::string hmac1;
+			Anope::string hmac2;
+			for (size_t i = 0; i < block_size; ++i)
+			{
+				hmac1.push_back(static_cast<char>(keybuf[i] ^ 0x5C));
+				hmac2.push_back(static_cast<char>(keybuf[i] ^ 0x36));
+			}
+			hmac2.append(data);
+			hmac1.append(Encrypt(hmac2));
+
+			return Encrypt(hmac1);
+		}
+
+		/** Converts a hash to its printable form. */
+		virtual Anope::string ToPrintable(const Anope::string &hash)
+		{
+			return Anope::Hex(hash);
+		}
 	};
 
-	class Provider : public Service
+	/** Helper template for creating simple providers of encryption contexts. */
+	template <typename T>
+	class SimpleProvider final
+		: public Provider
 	{
-	 public:
-		Provider(Module *creator, const Anope::string &sname) : Service(creator, "Encryption::Provider", sname) { }
-		virtual ~Provider() { }
+	public:
+		/** Creates a simple provider of encryption contexts.
+		 * @param creator The module that created this provider.
+		 * @param algorithm The name of the encryption algorithm.
+		 * @param bs The byte size of the block cipher.
+		 * @param ds The byte size of the resulting digest.
+		 */
+		SimpleProvider(Module *creator, const Anope::string &algorithm, size_t bs, size_t ds)
+			: Provider(creator, algorithm, bs, ds)
+		{
+		}
 
-		virtual Context *CreateContext(IV * = NULL) = 0;
-		virtual IV GetDefaultIV() = 0;
+		/** @copydoc Encryption::Provider::CreateContext. */
+		std::unique_ptr<Context> CreateContext() override
+		{
+			return std::make_unique<T>();
+		}
 	};
 }