New reseed_with_sources call on RNGs

Provides an easier way for an application to configure a list of
entropy sources they'd like to use, or add a custom entropy source to
their seeding.

Exposes some toggles for the global/default entropy sources to build.h

Adds basic entropy tests which runs the polls and does sanity checking
on the results, including compression tests if available. These are
less useful for the CSPRNG outputs but a good check for the ones
producing plain ASCII like the /proc reader.

2 files changed, 6 insertions, 7 deletions

diff --git a/src/lib/entropy/egd/es_egd.cpp b/src/lib/entropy/egd/es_egd.cpp
index d64b87ba1..9b625d051 100644
--- a/src/lib/entropy/egd/es_egd.cpp
+++ b/src/lib/entropy/egd/es_egd.cpp
@@ -137,19 +137,19 @@ EGD_EntropySource::~EGD_EntropySource()
 */
 void EGD_EntropySource::poll(Entropy_Accumulator& accum)
    {
-   const size_t READ_ATTEMPT = 32;
+   const size_t ENTROPY_BITS_PER_BYTE = 8;
 
    std::lock_guard<std::mutex> lock(m_mutex);
 
-   m_buf.resize(READ_ATTEMPT);
+   secure_vector<byte>& buf = accum.get_io_buf(BOTAN_SYSTEM_RNG_POLL_REQUEST);
 
    for(size_t i = 0; i != sockets.size(); ++i)
       {
-      size_t got = sockets[i].read(m_buf.data(), m_buf.size());
+      size_t got = sockets[i].read(buf.data(), buf.size());
 
       if(got)
          {
-         accum.add(m_buf.data(), got, 6);
+         accum.add(buf.data(), got, ENTROPY_BITS_PER_BYTE);
          break;
          }
       }
diff --git a/src/lib/entropy/egd/es_egd.h b/src/lib/entropy/egd/es_egd.h
index 7f7df1133..0b497a8bd 100644
--- a/src/lib/entropy/egd/es_egd.h
+++ b/src/lib/entropy/egd/es_egd.h
@@ -18,10 +18,10 @@ namespace Botan {
 /**
 * EGD Entropy Source
 */
-class EGD_EntropySource : public EntropySource
+class EGD_EntropySource : public Entropy_Source
    {
    public:
-      std::string name() const override { return "EGD/PRNGD"; }
+      std::string name() const override { return "egd"; }
 
       void poll(Entropy_Accumulator& accum) override;
 
@@ -44,7 +44,6 @@ class EGD_EntropySource : public EntropySource
 
       std::mutex m_mutex;
       std::vector<EGD_Socket> sockets;
-      secure_vector<byte> m_buf;
    };
 
 }