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.

1 files changed, 5 insertions, 3 deletions

diff --git a/src/lib/entropy/cryptoapi_rng/es_capi.cpp b/src/lib/entropy/cryptoapi_rng/es_capi.cpp
index 019b55a10..6ffc03c12 100644
--- a/src/lib/entropy/cryptoapi_rng/es_capi.cpp
+++ b/src/lib/entropy/cryptoapi_rng/es_capi.cpp
@@ -57,15 +57,17 @@ class CSP_Handle
 */
 void Win32_CAPI_EntropySource::poll(Entropy_Accumulator& accum)
    {
-   m_buf.resize(32);
+   const size_t ENTROPY_BITS_PER_BYTE = 8;
+
+   secure_vector<byte>& buf = accum.get_io_buf(BOTAN_SYSTEM_RNG_POLL_REQUEST);
 
    for(size_t i = 0; i != prov_types.size(); ++i)
       {
       CSP_Handle csp(prov_types[i]);
 
-      if(size_t got = csp.gen_random(m_buf.data(), m_buf.size()))
+      if(size_t got = csp.gen_random(buf.data(), buf.size()))
          {
-         accum.add(m_buf.data(), got, 6);
+         accum.add(buf.data(), got, ENTROPY_BITS_PER_BYTE);
          break;
          }
       }