diff options
author | Daniel Neus <[email protected]> | 2016-01-26 22:08:55 +0100 |
---|---|---|
committer | Daniel Neus <[email protected]> | 2016-01-26 22:09:32 +0100 |
commit | b642fa9bc637b3a7fe39f5640b9a2f6f9ea5f581 (patch) | |
tree | b92c905869c876c42b61b4b6a4130ab277ecb704 /src/lib/entropy/rdseed | |
parent | 0b021ef91f204fa6326a00c5a1550f5cabc5e3c9 (diff) |
move logic back into poll()
prevents filtering out any 0x00000000 outputs from RDRAND/RDSEED
Diffstat (limited to 'src/lib/entropy/rdseed')
-rw-r--r-- | src/lib/entropy/rdseed/rdseed.cpp | 48 |
1 files changed, 18 insertions, 30 deletions
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; + } } } } |