6 files changed, 544 insertions, 0 deletions
diff --git a/src/lib/modes/aead/gcm/clmul/clmul.cpp b/src/lib/modes/aead/gcm/clmul/clmul.cpp
new file mode 100644
index 000000000..cc6d581e3
--- /dev/null
+++ b/src/lib/modes/aead/gcm/clmul/clmul.cpp
@@ -0,0 +1,76 @@
+/*
+* CLMUL hook
+* (C) 2013 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/internal/clmul.h>
+#include <immintrin.h>
+
+namespace Botan {
+
+void gcm_multiply_clmul(byte x[16], const byte H[16])
+   {
+   /*
+   * Algorithms 1 and 5 from Intel's CLMUL guide
+   */
+   const __m128i BSWAP_MASK = _mm_set_epi8(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15);
+
+   __m128i a = _mm_loadu_si128(reinterpret_cast<const __m128i*>(&x[0]));
+   __m128i b = _mm_loadu_si128(reinterpret_cast<const __m128i*>(&H[0]));
+
+   a = _mm_shuffle_epi8(a, BSWAP_MASK);
+   b = _mm_shuffle_epi8(b, BSWAP_MASK);
+
+   __m128i T0, T1, T2, T3, T4, T5;
+
+   T0 = _mm_clmulepi64_si128(a, b, 0x00);
+   T1 = _mm_clmulepi64_si128(a, b, 0x01);
+   T2 = _mm_clmulepi64_si128(a, b, 0x10);
+   T3 = _mm_clmulepi64_si128(a, b, 0x11);
+
+   T1 = _mm_xor_si128(T1, T2);
+   T2 = _mm_slli_si128(T1, 8);
+   T1 = _mm_srli_si128(T1, 8);
+   T0 = _mm_xor_si128(T0, T2);
+   T3 = _mm_xor_si128(T3, T1);
+
+   T4 = _mm_srli_epi32(T0, 31);
+   T0 = _mm_slli_epi32(T0, 1);
+
+   T5 = _mm_srli_epi32(T3, 31);
+   T3 = _mm_slli_epi32(T3, 1);
+
+   T2 = _mm_srli_si128(T4, 12);
+   T5 = _mm_slli_si128(T5, 4);
+   T4 = _mm_slli_si128(T4, 4);
+   T0 = _mm_or_si128(T0, T4);
+   T3 = _mm_or_si128(T3, T5);
+   T3 = _mm_or_si128(T3, T2);
+
+   T4 = _mm_slli_epi32(T0, 31);
+   T5 = _mm_slli_epi32(T0, 30);
+   T2 = _mm_slli_epi32(T0, 25);
+
+   T4 = _mm_xor_si128(T4, T5);
+   T4 = _mm_xor_si128(T4, T2);
+   T5 = _mm_srli_si128(T4, 4);
+   T3 = _mm_xor_si128(T3, T5);
+   T4 = _mm_slli_si128(T4, 12);
+   T0 = _mm_xor_si128(T0, T4);
+   T3 = _mm_xor_si128(T3, T0);
+
+   T4 = _mm_srli_epi32(T0, 1);
+   T1 = _mm_srli_epi32(T0, 2);
+   T2 = _mm_srli_epi32(T0, 7);
+   T3 = _mm_xor_si128(T3, T1);
+   T3 = _mm_xor_si128(T3, T2);
+   T3 = _mm_xor_si128(T3, T4);
+
+   T3 = _mm_shuffle_epi8(T3, BSWAP_MASK);
+
+   _mm_storeu_si128(reinterpret_cast<__m128i*>(&x[0]), T3);
+   }
+
+}
diff --git a/src/lib/modes/aead/gcm/clmul/clmul.h b/src/lib/modes/aead/gcm/clmul/clmul.h
new file mode 100644
index 000000000..ba197f2f7
--- /dev/null
+++ b/src/lib/modes/aead/gcm/clmul/clmul.h
@@ -0,0 +1,14 @@
+/*
+* CLMUL hook
+* (C) 2013 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/types.h>
+
+namespace Botan {
+
+void gcm_multiply_clmul(byte x[16], const byte H[16]);
+
+}
diff --git a/src/lib/modes/aead/gcm/clmul/info.txt b/src/lib/modes/aead/gcm/clmul/info.txt
new file mode 100644
index 000000000..8a21b6ac2
--- /dev/null
+++ b/src/lib/modes/aead/gcm/clmul/info.txt
@@ -0,0 +1,8 @@
+
+define GCM_CLMUL 20131227
+
+need_isa clmul,ssse3
+
+<header:internal>
+clmul.h
+</header:internal>
diff --git a/src/lib/modes/aead/gcm/gcm.cpp b/src/lib/modes/aead/gcm/gcm.cpp
new file mode 100644
index 000000000..b39e6ac92
--- /dev/null
+++ b/src/lib/modes/aead/gcm/gcm.cpp
@@ -0,0 +1,290 @@
+/*
+* GCM Mode Encryption
+* (C) 2013 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/gcm.h>
+#include <botan/ctr.h>
+#include <botan/internal/xor_buf.h>
+#include <botan/loadstor.h>
+
+#if defined(BOTAN_HAS_GCM_CLMUL)
+  #include <botan/internal/clmul.h>
+  #include <botan/cpuid.h>
+#endif
+
+namespace Botan {
+
+void GHASH::gcm_multiply(secure_vector<byte>& x) const
+   {
+#if defined(BOTAN_HAS_GCM_CLMUL)
+   if(CPUID::has_clmul())
+      return gcm_multiply_clmul(&x[0], &m_H[0]);
+#endif
+
+   static const u64bit R = 0xE100000000000000;
+
+   u64bit H[2] = {
+      load_be<u64bit>(&m_H[0], 0),
+      load_be<u64bit>(&m_H[0], 1)
+   };
+
+   u64bit Z[2] = { 0, 0 };
+
+   // SSE2 might be useful here
+
+   for(size_t i = 0; i != 2; ++i)
+      {
+      const u64bit X = load_be<u64bit>(&x[0], i);
+
+      for(size_t j = 0; j != 64; ++j)
+         {
+         if((X >> (63-j)) & 1)
+            {
+            Z[0] ^= H[0];
+            Z[1] ^= H[1];
+            }
+
+         const u64bit r = (H[1] & 1) ? R : 0;
+
+         H[1] = (H[0] << 63) | (H[1] >> 1);
+         H[0] = (H[0] >> 1) ^ r;
+         }
+      }
+
+   store_be<u64bit>(&x[0], Z[0], Z[1]);
+   }
+
+void GHASH::ghash_update(secure_vector<byte>& ghash,
+                         const byte input[], size_t length)
+   {
+   const size_t BS = 16;
+
+   /*
+   This assumes if less than block size input then we're just on the
+   final block and should pad with zeros
+   */
+   while(length)
+      {
+      const size_t to_proc = std::min(length, BS);
+
+      xor_buf(&ghash[0], &input[0], to_proc);
+
+      gcm_multiply(ghash);
+
+      input += to_proc;
+      length -= to_proc;
+      }
+   }
+
+void GHASH::key_schedule(const byte key[], size_t length)
+   {
+   m_H.assign(key, key+length);
+   m_H_ad.resize(16);
+   m_ad_len = 0;
+   m_text_len = 0;
+   }
+
+void GHASH::start(const byte nonce[], size_t len)
+   {
+   m_nonce.assign(nonce, nonce + len);
+   m_ghash = m_H_ad;
+   }
+
+void GHASH::set_associated_data(const byte input[], size_t length)
+   {
+   zeroise(m_H_ad);
+
+   ghash_update(m_H_ad, input, length);
+   m_ad_len = length;
+   }
+
+void GHASH::update(const byte input[], size_t length)
+   {
+   BOTAN_ASSERT(m_ghash.size() == 16, "Key was set");
+
+   m_text_len += length;
+
+   ghash_update(m_ghash, input, length);
+   }
+
+void GHASH::add_final_block(secure_vector<byte>& hash,
+                            size_t ad_len, size_t text_len)
+   {
+   secure_vector<byte> final_block(16);
+   store_be<u64bit>(&final_block[0], 8*ad_len, 8*text_len);
+   ghash_update(hash, &final_block[0], final_block.size());
+   }
+
+secure_vector<byte> GHASH::final()
+   {
+   add_final_block(m_ghash, m_ad_len, m_text_len);
+
+   secure_vector<byte> mac;
+   mac.swap(m_ghash);
+
+   mac ^= m_nonce;
+   m_text_len = 0;
+   return mac;
+   }
+
+secure_vector<byte> GHASH::nonce_hash(const byte nonce[], size_t nonce_len)
+   {
+   BOTAN_ASSERT(m_ghash.size() == 0, "nonce_hash called during wrong time");
+   secure_vector<byte> y0(16);
+
+   ghash_update(y0, nonce, nonce_len);
+   add_final_block(y0, 0, nonce_len);
+
+   return y0;
+   }
+
+void GHASH::clear()
+   {
+   zeroise(m_H);
+   zeroise(m_H_ad);
+   m_ghash.clear();
+   m_text_len = m_ad_len = 0;
+   }
+
+/*
+* GCM_Mode Constructor
+*/
+GCM_Mode::GCM_Mode(BlockCipher* cipher, size_t tag_size) :
+   m_tag_size(tag_size),
+   m_cipher_name(cipher->name())
+   {
+   if(cipher->block_size() != BS)
+      throw std::invalid_argument("GCM requires a 128 bit cipher so cannot be used with " +
+                                  cipher->name());
+
+   m_ghash.reset(new GHASH);
+
+   m_ctr.reset(new CTR_BE(cipher)); // CTR_BE takes ownership of cipher
+
+   if(m_tag_size != 8 && m_tag_size != 16)
+      throw Invalid_Argument(name() + ": Bad tag size " + std::to_string(m_tag_size));
+   }
+
+void GCM_Mode::clear()
+   {
+   m_ctr->clear();
+   m_ghash->clear();
+   }
+
+std::string GCM_Mode::name() const
+   {
+   return (m_cipher_name + "/GCM");
+   }
+
+size_t GCM_Mode::update_granularity() const
+   {
+   return 4096; // CTR-BE's internal block size
+   }
+
+Key_Length_Specification GCM_Mode::key_spec() const
+   {
+   return m_ctr->key_spec();
+   }
+
+void GCM_Mode::key_schedule(const byte key[], size_t keylen)
+   {
+   m_ctr->set_key(key, keylen);
+
+   const std::vector<byte> zeros(BS);
+   m_ctr->set_iv(&zeros[0], zeros.size());
+
+   secure_vector<byte> H(BS);
+   m_ctr->encipher(H);
+   m_ghash->set_key(H);
+   }
+
+void GCM_Mode::set_associated_data(const byte ad[], size_t ad_len)
+   {
+   m_ghash->set_associated_data(ad, ad_len);
+   }
+
+secure_vector<byte> GCM_Mode::start(const byte nonce[], size_t nonce_len)
+   {
+   if(!valid_nonce_length(nonce_len))
+      throw Invalid_IV_Length(name(), nonce_len);
+
+   secure_vector<byte> y0(BS);
+
+   if(nonce_len == 12)
+      {
+      copy_mem(&y0[0], nonce, nonce_len);
+      y0[15] = 1;
+      }
+   else
+      {
+      y0 = m_ghash->nonce_hash(nonce, nonce_len);
+      }
+
+   m_ctr->set_iv(&y0[0], y0.size());
+
+   secure_vector<byte> m_enc_y0(BS);
+   m_ctr->encipher(m_enc_y0);
+
+   m_ghash->start(&m_enc_y0[0], m_enc_y0.size());
+
+   return secure_vector<byte>();
+   }
+
+void GCM_Encryption::update(secure_vector<byte>& buffer, size_t offset)
+   {
+   BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
+   const size_t sz = buffer.size() - offset;
+   byte* buf = &buffer[offset];
+
+   m_ctr->cipher(buf, buf, sz);
+   m_ghash->update(buf, sz);
+   }
+
+void GCM_Encryption::finish(secure_vector<byte>& buffer, size_t offset)
+   {
+   update(buffer, offset);
+   auto mac = m_ghash->final();
+   buffer += std::make_pair(&mac[0], tag_size());
+   }
+
+void GCM_Decryption::update(secure_vector<byte>& buffer, size_t offset)
+   {
+   BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
+   const size_t sz = buffer.size() - offset;
+   byte* buf = &buffer[offset];
+
+   m_ghash->update(buf, sz);
+   m_ctr->cipher(buf, buf, sz);
+   }
+
+void GCM_Decryption::finish(secure_vector<byte>& buffer, size_t offset)
+   {
+   BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
+   const size_t sz = buffer.size() - offset;
+   byte* buf = &buffer[offset];
+
+   BOTAN_ASSERT(sz >= tag_size(), "Have the tag as part of final input");
+
+   const size_t remaining = sz - tag_size();
+
+   // handle any final input before the tag
+   if(remaining)
+      {
+      m_ghash->update(buf, remaining);
+      m_ctr->cipher(buf, buf, remaining);
+      }
+
+   auto mac = m_ghash->final();
+
+   const byte* included_tag = &buffer[remaining];
+
+   if(!same_mem(&mac[0], included_tag, tag_size()))
+      throw Integrity_Failure("GCM tag check failed");
+
+   buffer.resize(offset + remaining);
+   }
+
+}
diff --git a/src/lib/modes/aead/gcm/gcm.h b/src/lib/modes/aead/gcm/gcm.h
new file mode 100644
index 000000000..12d66a3d1
--- /dev/null
+++ b/src/lib/modes/aead/gcm/gcm.h
@@ -0,0 +1,150 @@
+/*
+* GCM Mode
+* (C) 2013 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_AEAD_GCM_H__
+#define BOTAN_AEAD_GCM_H__
+
+#include <botan/aead.h>
+#include <botan/block_cipher.h>
+#include <botan/stream_cipher.h>
+#include <memory>
+
+namespace Botan {
+
+class GHASH;
+
+/**
+* GCM Mode
+*/
+class BOTAN_DLL GCM_Mode : public AEAD_Mode
+   {
+   public:
+      secure_vector<byte> start(const byte nonce[], size_t nonce_len) override;
+
+      void set_associated_data(const byte ad[], size_t ad_len) override;
+
+      std::string name() const override;
+
+      size_t update_granularity() const;
+
+      Key_Length_Specification key_spec() const override;
+
+      // GCM supports arbitrary nonce lengths
+      bool valid_nonce_length(size_t) const override { return true; }
+
+      size_t tag_size() const { return m_tag_size; }
+
+      void clear();
+   protected:
+      void key_schedule(const byte key[], size_t length) override;
+
+      GCM_Mode(BlockCipher* cipher, size_t tag_size);
+
+      const size_t BS = 16;
+
+      const size_t m_tag_size;
+      const std::string m_cipher_name;
+
+      std::unique_ptr<StreamCipher> m_ctr;
+      std::unique_ptr<GHASH> m_ghash;
+   };
+
+/**
+* GCM Encryption
+*/
+class BOTAN_DLL GCM_Encryption : public GCM_Mode
+   {
+   public:
+      /**
+      * @param cipher the 128 bit block cipher to use
+      * @param tag_size is how big the auth tag will be
+      */
+      GCM_Encryption(BlockCipher* cipher, size_t tag_size = 16) :
+         GCM_Mode(cipher, tag_size) {}
+
+      size_t output_length(size_t input_length) const override
+         { return input_length + tag_size(); }
+
+      size_t minimum_final_size() const override { return 0; }
+
+      void update(secure_vector<byte>& blocks, size_t offset = 0) override;
+
+      void finish(secure_vector<byte>& final_block, size_t offset = 0) override;
+   };
+
+/**
+* GCM Decryption
+*/
+class BOTAN_DLL GCM_Decryption : public GCM_Mode
+   {
+   public:
+      /**
+      * @param cipher the 128 bit block cipher to use
+      * @param tag_size is how big the auth tag will be
+      */
+      GCM_Decryption(BlockCipher* cipher, size_t tag_size = 16) :
+         GCM_Mode(cipher, tag_size) {}
+
+      size_t output_length(size_t input_length) const override
+         {
+         BOTAN_ASSERT(input_length > tag_size(), "Sufficient input");
+         return input_length - tag_size();
+         }
+
+      size_t minimum_final_size() const override { return tag_size(); }
+
+      void update(secure_vector<byte>& blocks, size_t offset = 0) override;
+
+      void finish(secure_vector<byte>& final_block, size_t offset = 0) override;
+   };
+
+/**
+* GCM's GHASH
+* Maybe a Transform?
+*/
+class BOTAN_DLL GHASH : public SymmetricAlgorithm
+   {
+   public:
+      void set_associated_data(const byte ad[], size_t ad_len);
+
+      secure_vector<byte> nonce_hash(const byte nonce[], size_t len);
+
+      void start(const byte nonce[], size_t len);
+
+      /*
+      * Assumes input len is multiple of 16
+      */
+      void update(const byte in[], size_t len);
+
+      secure_vector<byte> final();
+
+      Key_Length_Specification key_spec() const { return Key_Length_Specification(16); }
+
+      void clear();
+
+      std::string name() const { return "GHASH"; }
+   private:
+      void key_schedule(const byte key[], size_t key_len) override;
+
+      void gcm_multiply(secure_vector<byte>& x) const;
+
+      void ghash_update(secure_vector<byte>& x,
+                        const byte input[], size_t input_len);
+
+      void add_final_block(secure_vector<byte>& x,
+                           size_t ad_len, size_t pt_len);
+
+      secure_vector<byte> m_H;
+      secure_vector<byte> m_H_ad;
+      secure_vector<byte> m_nonce;
+      secure_vector<byte> m_ghash;
+      size_t m_ad_len = 0, m_text_len = 0;
+   };
+
+}
+
+#endif
diff --git a/src/lib/modes/aead/gcm/info.txt b/src/lib/modes/aead/gcm/info.txt
new file mode 100644
index 000000000..cf5f68bb5
--- /dev/null
+++ b/src/lib/modes/aead/gcm/info.txt
@@ -0,0 +1,6 @@
+define AEAD_GCM 20131128
+
+<requires>
+block
+ctr
+</requires>