In Randpool and HMAC_RNG, zeroize the I/O buffer used for holding polled

randomness data after the contents have been fed into the MAC.

2 files changed, 5 insertions, 0 deletions

diff --git a/src/rng/hmac_rng/hmac_rng.cpp b/src/rng/hmac_rng/hmac_rng.cpp
index 95b119b9d..5f59a1691 100644
--- a/src/rng/hmac_rng/hmac_rng.cpp
+++ b/src/rng/hmac_rng/hmac_rng.cpp
@@ -72,6 +72,7 @@ void HMAC_RNG::randomize(byte out[], u32bit length)
 
       source_index = (source_index + 1) % entropy_sources.size();
       extractor->update(io_buffer, got);
+      io_buffer.clear();
       }
    }
 
@@ -121,6 +122,7 @@ void HMAC_RNG::reseed_with_input(const byte input[], u32bit input_length)
 
          entropy += got;
          extractor->update(io_buffer, got);
+         io_buffer.clear();
          }
 
       for(u32bit j = 0; j != entropy_sources.size(); ++j)
@@ -130,6 +132,7 @@ void HMAC_RNG::reseed_with_input(const byte input[], u32bit input_length)
 
          entropy += got;
          extractor->update(io_buffer, got);
+         io_buffer.clear();
          }
       }
 
diff --git a/src/rng/randpool/randpool.cpp b/src/rng/randpool/randpool.cpp
index 0017c476c..e35ee22ca 100644
--- a/src/rng/randpool/randpool.cpp
+++ b/src/rng/randpool/randpool.cpp
@@ -129,6 +129,7 @@ void Randpool::reseed()
 
       mac->update(buffer, got);
       entropy_est += got;
+      buffer.clear();
       }
 
    // Then do a slow poll, until we think we have got enough entropy
@@ -141,6 +142,7 @@ void Randpool::reseed()
 
       if(entropy_est > 512)
          break;
+      buffer.clear();
       }
 
    SecureVector<byte> mac_val = mac->final();