Added implementation for GMAC

- Added GMAC class
- Integrated GMAC into MAC-Class test bench. Run GMAC tests using
  ./botan-test mac

5 files changed, 184 insertions, 1 deletions

diff --git a/src/lib/mac/gmac/gmac.cpp b/src/lib/mac/gmac/gmac.cpp
new file mode 100644
index 000000000..5d82456ae
--- /dev/null
+++ b/src/lib/mac/gmac/gmac.cpp
@@ -0,0 +1,76 @@
+/*
+ * GMAC
+ * (C) 2016 Matthias Gierlings, René Korthaus
+ *
+ * Botan is released under the Simplified BSD License (see license.txt)
+ */
+
+#include <botan/gmac.h>
+
+namespace Botan {
+
+GMAC* GMAC::make(const Spec& spec)
+   {
+   if(spec.arg_count() == 1)
+      {
+      if(auto bc = BlockCipher::create(spec.arg(0)))
+         return new GMAC(bc.release());
+      }
+   return nullptr;
+   }
+
+GMAC::GMAC(BlockCipher* cipher)
+    : m_iv(), m_aad(),
+      m_gcm(GCM_Encryption(cipher)), m_cipher(cipher->clone())
+   {
+   }
+
+void GMAC::clear()
+   {
+   m_gcm.clear();
+   zeroise(m_iv);
+   zeroise(m_aad);
+   }
+
+std::string GMAC::name() const
+   {
+   return "GMAC(" + m_cipher->name() + ")";
+   }
+
+size_t GMAC::output_length() const
+   {
+   return m_gcm.tag_size();
+   }
+
+void GMAC::add_data(const byte input[], size_t length)
+   {
+   m_aad.insert(m_aad.end(), input, input + length);
+   }
+
+void GMAC::start(const std::vector<byte>& nonce)
+   {
+   m_iv.assign(nonce.begin(), nonce.end());
+   }
+
+void GMAC::start(const secure_vector<byte>& nonce)
+   {
+   m_iv.assign(nonce.begin(), nonce.end());
+   }
+
+void GMAC::final_result(byte mac[])
+   {
+   secure_vector<byte> result;
+   m_gcm.set_associated_data(m_aad.data(), m_aad.size());
+   m_gcm.start(m_iv);
+   m_gcm.finish(result);
+   std::copy(result.begin(), result.end(), mac);
+
+   zeroise(m_aad);
+   m_aad.clear();
+   }
+
+MessageAuthenticationCode* GMAC::clone() const
+   {
+   return new GMAC(m_cipher->clone());
+   }
+}
diff --git a/src/lib/mac/gmac/gmac.h b/src/lib/mac/gmac/gmac.h
new file mode 100644
index 000000000..d83236b32
--- /dev/null
+++ b/src/lib/mac/gmac/gmac.h
@@ -0,0 +1,77 @@
+/*
+ * GMAC
+ * (C) 2016 Matthias Gierlings, René Korthaus
+ *
+ * Botan is released under the Simplified BSD License (see license.txt)
+ */
+
+#ifndef BOTAN_GMAC_H__
+#define BOTAN_GMAC_H__
+
+#include <botan/types.h>
+#include <botan/mac.h>
+#include <botan/gcm.h>
+#include <algorithm>
+
+namespace Botan {
+
+/**
+* GMAC
+*/
+class BOTAN_DLL GMAC : public MessageAuthenticationCode
+   {
+   public:
+      void clear() override;
+      std::string name() const override;
+      size_t output_length() const override;
+      MessageAuthenticationCode* clone() const override;
+
+      /**
+      * Must be called to set the initialization vector prior to GMAC
+      * calculation.
+      *
+      * @param nonce Initialization vector.
+      */
+      void start(const secure_vector<byte>& nonce);
+
+      /**
+      * Must be called to set the initialization vector prior to GMAC
+      * calculation.
+      *
+      * @param nonce Initialization vector.
+      */
+      void start(const std::vector<byte>& nonce);
+
+      Key_Length_Specification key_spec() const
+         {
+         return m_gcm.key_spec();
+         }
+
+      /**
+      * Creates a new GMAC instance.
+      *
+      * @param cipher the underlying block cipher to use
+      */
+      explicit GMAC(BlockCipher* cipher);
+
+      static GMAC* make(const Spec& spec);
+
+      GMAC(const GMAC&) = delete;
+      GMAC& operator=(const GMAC&) = delete;
+   private:
+      void add_data(const byte[], size_t) override;
+      void final_result(byte[]) override;
+
+      void key_schedule(const byte key[], size_t size) override
+        {
+        m_gcm.set_key(key, size);
+        }
+
+      secure_vector<byte> m_iv;
+      secure_vector<byte> m_aad;
+      GCM_Encryption m_gcm;
+      std::unique_ptr<BlockCipher> m_cipher;
+   };
+
+}
+#endif
diff --git a/src/lib/mac/gmac/info.txt b/src/lib/mac/gmac/info.txt
new file mode 100644
index 000000000..921690c93
--- /dev/null
+++ b/src/lib/mac/gmac/info.txt
@@ -0,0 +1,6 @@
+define GMAC 20160207
+
+<requires>
+gcm
+mac
+</requires>
diff --git a/src/lib/mac/mac.cpp b/src/lib/mac/mac.cpp
index 70807b39f..f2c5557c7 100644
--- a/src/lib/mac/mac.cpp
+++ b/src/lib/mac/mac.cpp
@@ -17,6 +17,10 @@
   #include <botan/cmac.h>
 #endif
 
+#if defined(BOTAN_HAS_GMAC)
+  #include <botan/gmac.h>
+#endif
+
 #if defined(BOTAN_HAS_HMAC)
   #include <botan/hmac.h>
 #endif
diff --git a/src/lib/mac/mac.h b/src/lib/mac/mac.h
index f3befc512..9c3614f33 100644
--- a/src/lib/mac/mac.h
+++ b/src/lib/mac/mac.h
@@ -59,7 +59,27 @@ class BOTAN_DLL MessageAuthenticationCode : public Buffered_Computation,
       virtual bool verify_mac(const byte in[], size_t length);
 
       /**
-      * @return a new object representing the same algorithm as *this
+      * Verify a MAC.
+      * @param in the MAC to verify as a byte array
+      * @return true if the MAC is valid, false otherwise
+      */
+      virtual bool verify_mac(const std::vector<byte>& in)
+         {
+         return verify_mac(in.data(), in.size());
+         }
+
+      /**
+      * Verify a MAC.
+      * @param in the MAC to verify as a byte array
+      * @return true if the MAC is valid, false otherwise
+      */
+      virtual bool verify_mac(const secure_vector<byte>& in)
+         {
+         return verify_mac(in.data(), in.size());
+         }
+
+      /**
+      * Get a new object representing the same algorithm as *this
       */
       virtual MessageAuthenticationCode* clone() const = 0;