diff options
Diffstat (limited to 'src/random.cpp')
| -rw-r--r-- | src/random.cpp | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/src/random.cpp b/src/random.cpp index 3b9df3edaa..7916643263 100644 --- a/src/random.cpp +++ b/src/random.cpp @@ -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 @@ -203,10 +261,43 @@ void GetRandBytes(unsigned char* buf, int num) } } +static void AddDataToRng(void* data, size_t len); + +void RandAddSeedSleep() +{ + int64_t nPerfCounter1 = GetPerformanceCounter(); + std::this_thread::sleep_for(std::chrono::milliseconds(1)); + int64_t nPerfCounter2 = GetPerformanceCounter(); + + // Combine with and update state + AddDataToRng(&nPerfCounter1, sizeof(nPerfCounter1)); + AddDataToRng(&nPerfCounter2, sizeof(nPerfCounter2)); + + memory_cleanse(&nPerfCounter1, sizeof(nPerfCounter1)); + memory_cleanse(&nPerfCounter2, sizeof(nPerfCounter2)); +} + + static std::mutex cs_rng_state; static unsigned char rng_state[32] = {0}; static uint64_t rng_counter = 0; +static void AddDataToRng(void* data, size_t len) { + CSHA512 hasher; + hasher.Write((const unsigned char*)&len, sizeof(len)); + hasher.Write((const unsigned char*)data, len); + unsigned char buf[64]; + { + std::unique_lock<std::mutex> lock(cs_rng_state); + hasher.Write(rng_state, sizeof(rng_state)); + hasher.Write((const unsigned char*)&rng_counter, sizeof(rng_counter)); + ++rng_counter; + hasher.Finalize(buf); + memcpy(rng_state, buf + 32, 32); + } + memory_cleanse(buf, 64); +} + void GetStrongRandBytes(unsigned char* out, int num) { assert(num <= 32); @@ -222,6 +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); @@ -271,6 +367,26 @@ void FastRandomContext::RandomSeed() requires_seed = false; } +uint256 FastRandomContext::rand256() +{ + if (bytebuf_size < 32) { + FillByteBuffer(); + } + uint256 ret; + memcpy(ret.begin(), bytebuf + 64 - bytebuf_size, 32); + bytebuf_size -= 32; + return ret; +} + +std::vector<unsigned char> FastRandomContext::randbytes(size_t len) +{ + std::vector<unsigned char> ret(len); + if (len > 0) { + rng.Output(&ret[0], len); + } + return ret; +} + FastRandomContext::FastRandomContext(const uint256& seed) : requires_seed(false), bytebuf_size(0), bitbuf_size(0) { rng.SetKey(seed.begin(), 32); @@ -328,3 +444,8 @@ FastRandomContext::FastRandomContext(bool fDeterministic) : requires_seed(!fDete uint256 seed; rng.SetKey(seed.begin(), 32); } + +void RandomInit() +{ + RDRandInit(); +} |