diff options
Diffstat (limited to 'src/random.cpp')
| -rw-r--r-- | src/random.cpp | 215 |
1 files changed, 191 insertions, 24 deletions
diff --git a/src/random.cpp b/src/random.cpp index 8284f457c..67efc7d94 100644 --- a/src/random.cpp +++ b/src/random.cpp @@ -16,6 +16,8 @@ #include <stdlib.h> #include <limits> +#include <chrono> +#include <thread> #ifndef WIN32 #include <sys/time.h> @@ -32,6 +34,8 @@ #include <sys/sysctl.h> #endif +#include <mutex> + #include <openssl/err.h> #include <openssl/rand.h> @@ -43,15 +47,86 @@ static void RandFailure() static inline int64_t GetPerformanceCounter() { - int64_t nCounter = 0; -#ifdef WIN32 - QueryPerformanceCounter((LARGE_INTEGER*)&nCounter); + // Read the hardware time stamp counter when available. + // See https://en.wikipedia.org/wiki/Time_Stamp_Counter for more information. +#if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64)) + return __rdtsc(); +#elif !defined(_MSC_VER) && defined(__i386__) + uint64_t r = 0; + __asm__ volatile ("rdtsc" : "=A"(r)); // Constrain the r variable to the eax:edx pair. + return r; +#elif !defined(_MSC_VER) && (defined(__x86_64__) || defined(__amd64__)) + uint64_t r1 = 0, r2 = 0; + __asm__ volatile ("rdtsc" : "=a"(r1), "=d"(r2)); // Constrain r1 to rax and r2 to rdx. + return (r2 << 32) | r1; +#else + // Fall back to using C++11 clock (usually microsecond or nanosecond precision) + return std::chrono::high_resolution_clock::now().time_since_epoch().count(); +#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() +{ + uint32_t eax, ecx, edx; +#if defined(__i386__) && ( defined(__PIC__) || defined(__PIE__)) + // Avoid clobbering ebx, as that is used for PIC on x86. + uint32_t tmp; + __asm__ ("mov %%ebx, %1; cpuid; mov %1, %%ebx": "=a"(eax), "=g"(tmp), "=c"(ecx), "=d"(edx) : "a"(1)); +#else + uint32_t ebx; + __asm__ ("cpuid": "=a"(eax), "=b"(ebx), "=c"(ecx), "=d"(edx) : "a"(1)); +#endif + //! When calling cpuid function #1, ecx register will have this set if RDRAND is available. + 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 - timeval t; - gettimeofday(&t, NULL); - nCounter = (int64_t)(t.tv_sec * 1000000 + t.tv_usec); + 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 nCounter; + return false; } void RandAddSeed() @@ -91,7 +166,7 @@ static void RandAddSeedPerfmon() if (ret == ERROR_SUCCESS) { RAND_add(vData.data(), nSize, nSize / 100.0); memory_cleanse(vData.data(), nSize); - LogPrint("rand", "%s: %lu bytes\n", __func__, nSize); + LogPrint(BCLog::RAND, "%s: %lu bytes\n", __func__, nSize); } else { static bool warned = false; // Warn only once if (!warned) { @@ -192,6 +267,43 @@ 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); @@ -207,8 +319,22 @@ 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); + 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); + } + // Produce output - hasher.Finalize(buf); memcpy(out, buf, num); memory_cleanse(buf, 64); } @@ -240,26 +366,42 @@ uint256 GetRandHash() return hash; } -FastRandomContext::FastRandomContext(bool fDeterministic) +void FastRandomContext::RandomSeed() { - // The seed values have some unlikely fixed points which we avoid. - if (fDeterministic) { - Rz = Rw = 11; - } else { - uint32_t tmp; - do { - GetRandBytes((unsigned char*)&tmp, 4); - } while (tmp == 0 || tmp == 0x9068ffffU); - Rz = tmp; - do { - GetRandBytes((unsigned char*)&tmp, 4); - } while (tmp == 0 || tmp == 0x464fffffU); - Rw = tmp; + uint256 seed = GetRandHash(); + rng.SetKey(seed.begin(), 32); + 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); } bool Random_SanityCheck() { + uint64_t start = GetPerformanceCounter(); + /* This does not measure the quality of randomness, but it does test that * OSRandom() overwrites all 32 bytes of the output given a maximum * number of tries. @@ -286,5 +428,30 @@ bool Random_SanityCheck() tries += 1; } while (num_overwritten < NUM_OS_RANDOM_BYTES && tries < MAX_TRIES); - return (num_overwritten == NUM_OS_RANDOM_BYTES); /* If this failed, bailed out after too many tries */ + if (num_overwritten != NUM_OS_RANDOM_BYTES) return false; /* If this failed, bailed out after too many tries */ + + // Check that GetPerformanceCounter increases at least during a GetOSRand() call + 1ms sleep. + std::this_thread::sleep_for(std::chrono::milliseconds(1)); + uint64_t stop = GetPerformanceCounter(); + if (stop == start) return false; + + // We called GetPerformanceCounter. Use it as entropy. + RAND_add((const unsigned char*)&start, sizeof(start), 1); + RAND_add((const unsigned char*)&stop, sizeof(stop), 1); + + return true; +} + +FastRandomContext::FastRandomContext(bool fDeterministic) : requires_seed(!fDeterministic), bytebuf_size(0), bitbuf_size(0) +{ + if (!fDeterministic) { + return; + } + uint256 seed; + rng.SetKey(seed.begin(), 32); +} + +void RandomInit() +{ + RDRandInit(); } |