Add Stateful_RNG

Handles fork checking for HMAC_RNG and HMAC_DRBG

AutoSeeded_RNG change - switch to HMAC_DRBG as default.

Start removing the io buffer from entropy poller.

Update default RNG poll bits to 256.

Fix McEliece test, was using wrong RNG API.

Update docs.

1 files changed, 47 insertions, 0 deletions

diff --git a/src/lib/rng/auto_rng.h b/src/lib/rng/auto_rng.h
new file mode 100644
index 000000000..b51390ae2
--- /dev/null
+++ b/src/lib/rng/auto_rng.h
@@ -0,0 +1,47 @@
+/*
+* Auto Seeded RNG
+* (C) 2008 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#ifndef BOTAN_AUTO_SEEDING_RNG_H__
+#define BOTAN_AUTO_SEEDING_RNG_H__
+
+#include <botan/rng.h>
+
+namespace Botan {
+
+class BOTAN_DLL AutoSeeded_RNG final : public RandomNumberGenerator
+   {
+   public:
+      void randomize(byte out[], size_t len) override;
+
+      void randomize_with_input(byte output[], size_t output_len,
+                                const byte input[], size_t input_len) override;
+
+      bool is_seeded() const override { return m_rng->is_seeded(); }
+
+      void clear() override { m_rng->clear(); m_counter = 0; }
+
+      std::string name() const override { return m_rng->name(); }
+
+      size_t reseed_with_sources(Entropy_Sources& srcs,
+                               size_t poll_bits,
+                               std::chrono::milliseconds poll_timeout) override
+         {
+         return m_rng->reseed_with_sources(srcs, poll_bits, poll_timeout);
+         }
+
+      void add_entropy(const byte in[], size_t len) override
+         { m_rng->add_entropy(in, len); }
+
+      AutoSeeded_RNG(size_t bytes_before_reseed = BOTAN_RNG_MAX_OUTPUT_BEFORE_RESEED);
+   private:
+      std::unique_ptr<RandomNumberGenerator> m_rng;
+      uint32_t m_counter = 0;
+   };
+
+}
+
+#endif