From b642fa9bc637b3a7fe39f5640b9a2f6f9ea5f581 Mon Sep 17 00:00:00 2001
From: Daniel Neus <daniel@neus-online.eu>
Date: Tue, 26 Jan 2016 22:08:55 +0100
Subject: move logic back into poll()

prevents filtering out any 0x00000000 outputs from RDRAND/RDSEED
---
 src/lib/entropy/rdseed/rdseed.cpp | 48 +++++++++++++++------------------------
 1 file changed, 18 insertions(+), 30 deletions(-)

(limited to 'src/lib/entropy/rdseed')

diff --git a/src/lib/entropy/rdseed/rdseed.cpp b/src/lib/entropy/rdseed/rdseed.cpp
index adca605f6..bcef9ad83 100644
--- a/src/lib/entropy/rdseed/rdseed.cpp
+++ b/src/lib/entropy/rdseed/rdseed.cpp
@@ -10,47 +10,35 @@
 #include <botan/build.h>
 
 #if !defined(BOTAN_USE_GCC_INLINE_ASM)
-#include <immintrin.h>
+  #include <immintrin.h>
 #endif
 
 namespace Botan {
 
-namespace {
-
-/// @returns 0 if RdSeed failed after @param max_retries otherwise the 32 bit random number generated by RdSeed
-uint32_t get_32bit_random(const uint32_t max_retries) {
-   for(size_t i = 0; i != max_retries; ++i)
-      {
-      uint32_t r = 0;
-
-#if defined(BOTAN_USE_GCC_INLINE_ASM)
-      int cf = 0;
-
-      // Encoding of rdseed %eax
-      asm(".byte 0x0F, 0xC7, 0xF8; adcl $0,%1" :
-      "=a" (r), "=r" (cf) : "0" (r), "1" (cf) : "cc");
-#else
-      int cf = _rdseed32_step(&r);
-#endif
-      if(1 == cf)
-         {
-         return r;
-         }
-      }
-   return 0;
-   }
-}
-
 void Intel_Rdseed::poll(Entropy_Accumulator& accum) {
    if(!CPUID::has_rdseed())
       return;
 
    for(size_t i = 0; i != BOTAN_ENTROPY_INTEL_RNG_POLLS; ++i)
       {
-      uint32_t random = get_32bit_random(BOTAN_ENTROPY_RDSEED_RETRIES);
-      if(random)
+      for(size_t i = 0; i != BOTAN_ENTROPY_RDSEED_RETRIES; ++i)
          {
-         accum.add(random, BOTAN_ENTROPY_ESTIMATE_HARDWARE_RNG);
+         uint32_t r = 0;
+
+#if defined(BOTAN_USE_GCC_INLINE_ASM)
+         int cf = 0;
+
+         // Encoding of rdseed %eax
+         asm(".byte 0x0F, 0xC7, 0xF8; adcl $0,%1" :
+             "=a" (r), "=r" (cf) : "0" (r), "1" (cf) : "cc");
+#else
+         int cf = _rdseed32_step(&r);
+#endif
+         if(1 == cf)
+            {
+            accum.add(r, BOTAN_ENTROPY_ESTIMATE_HARDWARE_RNG);
+            break;
+            }
          }
       }
    }
-- 
cgit v1.2.3