Browse Source

Merge #10377: Use rdrand as entropy source on supported platforms

cb24c85 Use rdrand as entropy source on supported platforms (Pieter Wuille)

Tree-SHA512: c42eaa01a14e6bc097c70b6bf8540d61854c2f76cb32be69c2a3c411a126f7b4bf4a4486e4493c4cc367cc689319abde0d4adb799d29a54fd3e81767ce0766fc
tags/v0.15.1
Wladimir J. van der Laan 3 years ago
parent
commit
b63be2c685
No account linked to committer's email address
4 changed files with 73 additions and 0 deletions
  1. 1
    0
      src/init.cpp
  2. 68
    0
      src/random.cpp
  3. 3
    0
      src/random.h
  4. 1
    0
      src/test/test_bitcoin.cpp

+ 1
- 0
src/init.cpp View File

@@ -1170,6 +1170,7 @@ bool AppInitSanityChecks()
// ********************************************************* Step 4: sanity checks

// Initialize elliptic curve code
RandomInit();
ECC_Start();
globalVerifyHandle.reset(new ECCVerifyHandle());


+ 68
- 0
src/random.cpp View File

@@ -65,6 +65,64 @@ static inline int64_t GetPerformanceCounter()
#endif
}


#if defined(__x86_64__) || defined(__amd64__) || defined(__i386__)
static std::atomic<bool> hwrand_initialized{false};
static bool rdrand_supported = false;
static constexpr uint32_t CPUID_F1_ECX_RDRAND = 0x40000000;
static void RDRandInit()
{
//! When calling cpuid function #1, ecx register will have this set if RDRAND is available.
// Avoid clobbering ebx, as that is used for PIC on x86.
uint32_t eax, tmp, ecx, edx;
__asm__ ("mov %%ebx, %1; cpuid; mov %1, %%ebx": "=a"(eax), "=g"(tmp), "=c"(ecx), "=d"(edx) : "a"(1));
if (ecx & CPUID_F1_ECX_RDRAND) {
LogPrintf("Using RdRand as entropy source\n");
rdrand_supported = true;
}
hwrand_initialized.store(true);
}
#else
static void RDRandInit() {}
#endif

static bool GetHWRand(unsigned char* ent32) {
#if defined(__x86_64__) || defined(__amd64__) || defined(__i386__)
assert(hwrand_initialized.load(std::memory_order_relaxed));
if (rdrand_supported) {
uint8_t ok;
// Not all assemblers support the rdrand instruction, write it in hex.
#ifdef __i386__
for (int iter = 0; iter < 4; ++iter) {
uint32_t r1, r2;
__asm__ volatile (".byte 0x0f, 0xc7, 0xf0;" // rdrand %eax
".byte 0x0f, 0xc7, 0xf2;" // rdrand %edx
"setc %2" :
"=a"(r1), "=d"(r2), "=q"(ok) :: "cc");
if (!ok) return false;
WriteLE32(ent32 + 8 * iter, r1);
WriteLE32(ent32 + 8 * iter + 4, r2);
}
#else
uint64_t r1, r2, r3, r4;
__asm__ volatile (".byte 0x48, 0x0f, 0xc7, 0xf0, " // rdrand %rax
"0x48, 0x0f, 0xc7, 0xf3, " // rdrand %rbx
"0x48, 0x0f, 0xc7, 0xf1, " // rdrand %rcx
"0x48, 0x0f, 0xc7, 0xf2; " // rdrand %rdx
"setc %4" :
"=a"(r1), "=b"(r2), "=c"(r3), "=d"(r4), "=q"(ok) :: "cc");
if (!ok) return false;
WriteLE64(ent32, r1);
WriteLE64(ent32 + 8, r2);
WriteLE64(ent32 + 16, r3);
WriteLE64(ent32 + 24, r4);
#endif
return true;
}
#endif
return false;
}

void RandAddSeed()
{
// Seed with CPU performance counter
@@ -255,6 +313,11 @@ void GetStrongRandBytes(unsigned char* out, int num)
GetOSRand(buf);
hasher.Write(buf, 32);

// Third source: HW RNG, if available.
if (GetHWRand(buf)) {
hasher.Write(buf, 32);
}

// Combine with and update state
{
std::unique_lock<std::mutex> lock(cs_rng_state);
@@ -381,3 +444,8 @@ FastRandomContext::FastRandomContext(bool fDeterministic) : requires_seed(!fDete
uint256 seed;
rng.SetKey(seed.begin(), 32);
}

void RandomInit()
{
RDRandInit();
}

+ 3
- 0
src/random.h View File

@@ -140,4 +140,7 @@ void GetOSRand(unsigned char *ent32);
*/
bool Random_SanityCheck();

/** Initialize the RNG. */
void RandomInit();

#endif // BITCOIN_RANDOM_H

+ 1
- 0
src/test/test_bitcoin.cpp View File

@@ -33,6 +33,7 @@ extern void noui_connect();

BasicTestingSetup::BasicTestingSetup(const std::string& chainName)
{
RandomInit();
ECC_Start();
SetupEnvironment();
SetupNetworking();

Loading…
Cancel
Save