Merge master into this branch, resolving conflicts with #457/#576

which recently landed on master.

12 files changed, 86 insertions, 13 deletions

diff --git a/src/lib/stream/chacha/chacha.cpp b/src/lib/stream/chacha/chacha.cpp
index ac81fd70d..40da93029 100644
--- a/src/lib/stream/chacha/chacha.cpp
+++ b/src/lib/stream/chacha/chacha.cpp
@@ -12,8 +12,8 @@ namespace Botan {
 
 ChaCha::ChaCha(size_t rounds) : m_rounds(rounds)
    {
-   if(m_rounds != 12 && m_rounds != 20)
-      throw Invalid_Argument("ChaCha only supports 12 or 20 rounds");
+   if(m_rounds != 8 && m_rounds != 12 && m_rounds != 20)
+      throw Invalid_Argument("ChaCha only supports 8, 12 or 20 rounds");
    }
 
 namespace {
@@ -67,7 +67,6 @@ void chacha(byte output[64], const u32bit input[16], size_t rounds)
    store_le(x14 + input[14], output + 4 * 14);
    store_le(x15 + input[15], output + 4 * 15);
    }
-
 }
 
 /*
@@ -173,4 +172,27 @@ std::string ChaCha::name() const
    return "ChaCha(" + std::to_string(m_rounds) + ")";
    }
 
+void ChaCha::seek(u64bit offset)
+   {
+   if (m_state.size() == 0 && m_buffer.size() == 0)
+      {
+         throw Invalid_State("You have to setup the stream cipher (key and iv)");
+      }
+
+   m_position = offset % m_buffer.size();
+
+   u64bit counter = offset / m_buffer.size();
+
+   byte out[8];
+
+   store_le(counter, out);
+
+   m_state[12] = load_le<u32bit>(out, 0);
+   m_state[13] += load_le<u32bit>(out, 1);
+
+   chacha(m_buffer.data(), m_state.data(), m_rounds);
+
+   ++m_state[12];
+   m_state[13] += (m_state[12] == 0);
+   }
 }
diff --git a/src/lib/stream/chacha/chacha.h b/src/lib/stream/chacha/chacha.h
index ba93d6260..f8f42e41d 100644
--- a/src/lib/stream/chacha/chacha.h
+++ b/src/lib/stream/chacha/chacha.h
@@ -21,7 +21,7 @@ class BOTAN_DLL ChaCha final : public StreamCipher
       StreamCipher* clone() const override { return new ChaCha(m_rounds); }
 
       /**
-      * Currently only 12 or 20 rounds are supported, all others
+      * Currently only 8, 12 or 20 rounds are supported, all others
       * will throw an exception
       */
       ChaCha(size_t rounds);
@@ -42,6 +42,8 @@ class BOTAN_DLL ChaCha final : public StreamCipher
 
       std::string name() const override;
 
+      void seek(u64bit offset) override;
+
    private:
       void key_schedule(const byte key[], size_t key_len) override;
 
diff --git a/src/lib/stream/ctr/ctr.cpp b/src/lib/stream/ctr/ctr.cpp
index 88c7a8d8e..43609ba2d 100644
--- a/src/lib/stream/ctr/ctr.cpp
+++ b/src/lib/stream/ctr/ctr.cpp
@@ -23,10 +23,23 @@ CTR_BE::CTR_BE(BlockCipher* ciph) :
    m_cipher(ciph),
    m_counter(m_cipher->parallel_bytes()),
    m_pad(m_counter.size()),
+   m_ctr_size(m_cipher->block_size()),
    m_pad_pos(0)
    {
    }
 
+CTR_BE::CTR_BE(BlockCipher* cipher, size_t ctr_size) :
+   m_cipher(cipher),
+   m_counter(m_cipher->parallel_bytes()),
+   m_pad(m_counter.size()),
+   m_ctr_size(ctr_size),
+   m_pad_pos(0)
+   {
+   //BOTAN_CHECK_ARG(m_ctr_size > 0 && m_ctr_size <= cipher->block_size(), "Invalid CTR size");
+   if(m_ctr_size == 0 || m_ctr_size > m_cipher->block_size())
+      throw Invalid_Argument("Invalid CTR-BE counter size");
+   }
+
 void CTR_BE::clear()
    {
    m_cipher->clear();
@@ -79,7 +92,7 @@ void CTR_BE::set_iv(const byte iv[], size_t iv_len)
       {
       buffer_insert(m_counter, i*bs, &m_counter[(i-1)*bs], bs);
 
-      for(size_t j = 0; j != bs; ++j)
+      for(size_t j = 0; j != m_ctr_size; ++j)
          if(++m_counter[i*bs + (bs - 1 - j)])
             break;
       }
@@ -99,7 +112,7 @@ void CTR_BE::increment_counter()
    for(size_t i = 0; i != n_wide; ++i)
       {
       uint16_t carry = static_cast<uint16_t>(n_wide);
-      for(size_t j = 0; carry && j != bs; ++j)
+      for(size_t j = 0; carry && j != m_ctr_size; ++j)
          {
          const size_t off = i*bs + (bs-1-j);
          const uint16_t cnt = static_cast<uint16_t>(m_counter[off]) + carry;
@@ -112,4 +125,8 @@ void CTR_BE::increment_counter()
    m_pad_pos = 0;
    }
 
+void CTR_BE::seek(u64bit)
+   {
+   throw Not_Implemented("CTR_BE::seek");
+   }
 }
diff --git a/src/lib/stream/ctr/ctr.h b/src/lib/stream/ctr/ctr.h
index 8e931605c..5d5556254 100644
--- a/src/lib/stream/ctr/ctr.h
+++ b/src/lib/stream/ctr/ctr.h
@@ -44,12 +44,17 @@ class BOTAN_DLL CTR_BE final : public StreamCipher
       * @param cipher the underlying block cipher to use
       */
       explicit CTR_BE(BlockCipher* cipher);
+
+      CTR_BE(BlockCipher* cipher, size_t ctr_size);
+
+      void seek(u64bit offset) override;
    private:
       void key_schedule(const byte key[], size_t key_len) override;
       void increment_counter();
 
       std::unique_ptr<BlockCipher> m_cipher;
       secure_vector<byte> m_counter, m_pad;
+      size_t m_ctr_size;
       size_t m_pad_pos;
    };
 
diff --git a/src/lib/stream/ofb/ofb.cpp b/src/lib/stream/ofb/ofb.cpp
index e8cb463db..3337a0c14 100644
--- a/src/lib/stream/ofb/ofb.cpp
+++ b/src/lib/stream/ofb/ofb.cpp
@@ -73,4 +73,9 @@ void OFB::set_iv(const byte iv[], size_t iv_len)
    m_buf_pos = 0;
    }
 
+
+void OFB::seek(u64bit)
+   {
+   throw Exception("OFB does not support seeking");
+   }
 }
diff --git a/src/lib/stream/ofb/ofb.h b/src/lib/stream/ofb/ofb.h
index fecd47d9d..127a06578 100644
--- a/src/lib/stream/ofb/ofb.h
+++ b/src/lib/stream/ofb/ofb.h
@@ -44,6 +44,8 @@ class BOTAN_DLL OFB final : public StreamCipher
       * @param cipher the underlying block cipher to use
       */
       explicit OFB(BlockCipher* cipher);
+
+      void seek(u64bit offset) override;
    private:
       void key_schedule(const byte key[], size_t key_len) override;
 
diff --git a/src/lib/stream/rc4/rc4.cpp b/src/lib/stream/rc4/rc4.cpp
index 895f38091..e5ea2e2b8 100644
--- a/src/lib/stream/rc4/rc4.cpp
+++ b/src/lib/stream/rc4/rc4.cpp
@@ -6,6 +6,7 @@
 */
 
 #include <botan/rc4.h>
+#include <botan/exceptn.h>
 
 namespace Botan {
 
@@ -35,6 +36,11 @@ void RC4::cipher(const byte in[], byte out[], size_t length)
    m_position += length;
    }
 
+void RC4::set_iv(const byte*, size_t)
+   {
+   throw Exception("RC4 does not support an IV");
+   }
+
 /*
 * Generate cipher stream
 */
@@ -113,4 +119,8 @@ void RC4::clear()
 */
 RC4::RC4(size_t s) : m_SKIP(s) {}
 
+void RC4::seek(u64bit)
+   {
+   throw Exception("RC4 does not support seeking");
+   }
 }
diff --git a/src/lib/stream/rc4/rc4.h b/src/lib/stream/rc4/rc4.h
index f166a2772..82dd6097b 100644
--- a/src/lib/stream/rc4/rc4.h
+++ b/src/lib/stream/rc4/rc4.h
@@ -21,6 +21,8 @@ class BOTAN_DLL RC4 final : public StreamCipher
    public:
       void cipher(const byte in[], byte out[], size_t length) override;
 
+      void set_iv(const byte iv[], size_t iv_len) override;
+
       void clear() override;
       std::string name() const override;
 
@@ -39,6 +41,8 @@ class BOTAN_DLL RC4 final : public StreamCipher
       explicit RC4(size_t skip = 0);
 
       ~RC4() { clear(); }
+
+      void seek(u64bit offset) override;
    private:
       void key_schedule(const byte[], size_t) override;
       void generate();
diff --git a/src/lib/stream/salsa20/salsa20.cpp b/src/lib/stream/salsa20/salsa20.cpp
index 1d3fe3d28..f11fe5e59 100644
--- a/src/lib/stream/salsa20/salsa20.cpp
+++ b/src/lib/stream/salsa20/salsa20.cpp
@@ -227,4 +227,8 @@ void Salsa20::clear()
    m_position = 0;
    }
 
+void Salsa20::seek(u64bit)
+   {
+   throw Not_Implemented("Salsa20::seek");
+   }
 }
diff --git a/src/lib/stream/salsa20/salsa20.h b/src/lib/stream/salsa20/salsa20.h
index 7e75470da..8256ea4db 100644
--- a/src/lib/stream/salsa20/salsa20.h
+++ b/src/lib/stream/salsa20/salsa20.h
@@ -33,6 +33,8 @@ class BOTAN_DLL Salsa20 final : public StreamCipher
       void clear() override;
       std::string name() const override;
       StreamCipher* clone() const override { return new Salsa20; }
+
+      void seek(u64bit offset) override;
    private:
       void key_schedule(const byte key[], size_t key_len) override;
 
diff --git a/src/lib/stream/stream_cipher.cpp b/src/lib/stream/stream_cipher.cpp
index 6f98df1fb..cd6400d8f 100644
--- a/src/lib/stream/stream_cipher.cpp
+++ b/src/lib/stream/stream_cipher.cpp
@@ -44,12 +44,6 @@ std::vector<std::string> StreamCipher::providers(const std::string& algo_spec)
 StreamCipher::StreamCipher() {}
 StreamCipher::~StreamCipher() {}
 
-void StreamCipher::set_iv(const byte[], size_t iv_len)
-   {
-   if(!valid_iv_length(iv_len))
-      throw Invalid_IV_Length(name(), iv_len);
-   }
-
 #if defined(BOTAN_HAS_CHACHA)
 BOTAN_REGISTER_T_1LEN(StreamCipher, ChaCha, 20);
 #endif
diff --git a/src/lib/stream/stream_cipher.h b/src/lib/stream/stream_cipher.h
index bff1fd1a6..e08bee0ce 100644
--- a/src/lib/stream/stream_cipher.h
+++ b/src/lib/stream/stream_cipher.h
@@ -67,7 +67,7 @@ class BOTAN_DLL StreamCipher : public SymmetricAlgorithm
       * @param iv the initialization vector
       * @param iv_len the length of the IV in bytes
       */
-      virtual void set_iv(const byte[], size_t iv_len);
+      virtual void set_iv(const byte[], size_t iv_len) = 0;
 
       /**
       * @param iv_len the length of the IV in bytes
@@ -80,6 +80,12 @@ class BOTAN_DLL StreamCipher : public SymmetricAlgorithm
       */
       virtual StreamCipher* clone() const = 0;
 
+      /**
+      * Set the offset and the state used later to generate the keystream
+      * @param offset the offset where we begin to generate the keystream
+      */
+      virtual void seek(u64bit offset) = 0;
+
       StreamCipher();
       virtual ~StreamCipher();
    };