From 60fede7678330739a2a797841219d72a40250489 Mon Sep 17 00:00:00 2001
From: Brian Cox <bcox@tripwire.com>
Date: Sat, 15 Jul 2017 22:59:50 -0700
Subject: [PATCH] Tweak device random stuff for Linux

---
 src/twcrypto/crypto.cpp | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/src/twcrypto/crypto.cpp b/src/twcrypto/crypto.cpp
index 1eb5953..72f8172 100644
--- a/src/twcrypto/crypto.cpp
+++ b/src/twcrypto/crypto.cpp
@@ -1241,37 +1241,34 @@ cHashedKey192::~cHashedKey192()
     RandomizeBytes(mKey, KEYLEN);
 }
 
+/////////////////////////////////////////////////////////
+
+#if HAVE_DEVICE_RANDOM
 
 static bool randomize_by_device(const char* device_name, int8* destbuf, int len)
 {
-    int dev_random = open("/dev/random", O_RDONLY|O_NONBLOCK);
-    if (dev_random >= 0)
+    int rng_device = open(device_name, O_RDONLY|O_NONBLOCK);
+    if (rng_device >= 0)
     {
-        int bytes_read = read(dev_random, destbuf, len);
-        close(dev_random);
+        int bytes_read = read(rng_device, destbuf, len);
+	close(rng_device);
         if (bytes_read == len)
-            return true;
+	    return true;
     }
 
     return false;
 }
+#else
+static bool gRandomizeBytesSeeded = false;
+#endif
 
 ///////////////////////////////////////////////////////////////////////////////
 // void RandomizeBytes(byte* destbuf, int len) -- Fill a buffer with random bytes
 
-static bool gRandomizeBytesSeeded = false;
-
 void RandomizeBytes(int8* destbuf, int len)
 {
 #if HAVE_DEVICE_RANDOM
 
-#if HAVE_DEV_RANDOM
-    if (randomize_by_device("/dev/random", destbuf, len))
-        return;
-
-    iUserNotify::GetInstance()->Notify( iUserNotify::V_NORMAL, "Could not read from /dev/random, falling back to /dev/urandom");
-#endif
-
 #if HAVE_DEV_URANDOM
     if (randomize_by_device("/dev/urandom", destbuf, len))
         return;
@@ -1282,6 +1279,11 @@ void RandomizeBytes(int8* destbuf, int len)
         return;
 #endif
 
+#if HAVE_DEV_RANDOM
+    if (randomize_by_device("/dev/random", destbuf, len))
+        return;
+#endif
+    
     ThrowAndAssert(eInternal(_T("Failed to read from any RNG devices")));
 
 // TODO: OpenSSL or other impls that are better than the default one