Better entropy for getRandomBytes

1 files changed, 38 insertions, 10 deletions

diff --git a/src/SimpleRandomizer.cc b/src/SimpleRandomizer.cc
index 8a055d66..8dbef82f 100644
--- a/src/SimpleRandomizer.cc
+++ b/src/SimpleRandomizer.cc
@@ -39,6 +39,11 @@
 #include <cstdlib>
 #include <cassert>
 #include <cstring>
+#include <iostream>
+
+#ifdef __APPLE__
+#  include <Security/SecRandom.h>
+#endif // __APPLE__
 
 #include "a2time.h"
 #include "a2functional.h"
@@ -89,17 +94,40 @@ void SimpleRandomizer::getRandomBytes(unsigned char* buf, size_t len)
 {
 #ifdef __MINGW32__
   BOOL r = CryptGenRandom(provider_, len, reinterpret_cast<BYTE*>(buf));
-  assert(r);
-#else  // ! __MINGW32__
-  auto ubuf = reinterpret_cast<result_type*>(buf);
-  size_t q = len / sizeof(result_type);
-  auto dis = std::uniform_int_distribution<result_type>();
-  for (; q > 0; --q, ++ubuf) {
-    *ubuf = dis(gen_);
+  if (!r) {
+    assert(r);
+    abort();
+  }
+#elif defined(__APPLE__)
+  auto rv = SecRandomCopyBytes(kSecRandomDefault, len, buf);
+  assert(errSecSuccess == rv);
+#else  // !__MINGW32__ && !__APPLE__
+  constexpr static size_t blocklen = 256;
+  auto iter = len / blocklen;
+  auto p = buf;
+
+  for (size_t i = 0; i < iter; ++i) {
+    auto rv = getentropy(p, blocklen);
+    if (rv != 0) {
+      std::cerr << "getentropy: " << strerror(errno) << std::endl;
+      assert(0);
+      abort();
+    }
+
+    p += blocklen;
+  }
+
+  auto rem = len - iter * blocklen;
+  if (rem == 0) {
+    return;
+  }
+
+  auto rv = getentropy(p, rem);
+  if (rv != 0) {
+    std::cerr << "getentropy: " << strerror(errno) << std::endl;
+    assert(0);
+    abort();
   }
-  const size_t r = len % sizeof(result_type);
-  auto last = dis(gen_);
-  memcpy(ubuf, &last, r);
 #endif // ! __MINGW32__
 }