diff options
Diffstat (limited to 'src/lib/entropy/rdseed/rdseed.cpp')
| -rw-r--r-- | src/lib/entropy/rdseed/rdseed.cpp | 43 |
1 files changed, 26 insertions, 17 deletions
diff --git a/src/lib/entropy/rdseed/rdseed.cpp b/src/lib/entropy/rdseed/rdseed.cpp index 91306769d..b995ab5d4 100644 --- a/src/lib/entropy/rdseed/rdseed.cpp +++ b/src/lib/entropy/rdseed/rdseed.cpp @@ -7,6 +7,7 @@ #include <botan/internal/rdseed.h> #include <botan/cpuid.h> +#include <botan/build.h> #if !defined(BOTAN_USE_GCC_INLINE_ASM) #include <immintrin.h> @@ -14,32 +15,40 @@ namespace Botan { -/* -* Get the timestamp -*/ -void Intel_Rdseed::poll(Entropy_Accumulator& accum) - { - if(!CPUID::has_rdseed()) - return; - - const size_t RDSEED_POLLS = 32; - - for(size_t i = 0; i != RDSEED_POLLS; ++i) +/// @returns 0 if RdSeed failed after @param max_retries otherwise the 32 bit random number generated by RdSeed +uint32_t Intel_Rdseed::get32BitRandom( const uint32_t max_retries ) { + for ( size_t i = 0; i != max_retries; ++i ) { - unsigned int r = 0; + 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"); + asm( ".byte 0x0F, 0xC7, 0xF8; adcl $0,%1" : + "=a" ( r ), "=r" ( cf ) : "0" ( r ), "1" ( cf ) : "cc" ); #else - int cf = _rdseed32_step(&r); + int cf = _rdseed32_step( &r ); #endif + if ( 1 == cf ) + { + return r; + } + } + return 0; + } - if(cf == 1) - accum.add(r, BOTAN_ENTROPY_ESTIMATE_HARDWARE_RNG); +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 = get32BitRandom( BOTAN_ENTROPY_RDSEED_RETRIES ); + if ( random ) + { + accum.add( random, BOTAN_ENTROPY_ESTIMATE_HARDWARE_RNG ); + } } } |