diff --git a/src/init.cpp b/src/init.cpp index 3bbdb16c3..298cc715c 100644 --- a/src/init.cpp +++ b/src/init.cpp @@ -1168,6 +1168,7 @@ bool AppInitSanityChecks() // ********************************************************* Step 4: sanity checks // Initialize elliptic curve code + RandomInit(); ECC_Start(); globalVerifyHandle.reset(new ECCVerifyHandle()); diff --git a/src/random.cpp b/src/random.cpp index de7553c82..fb7160c8c 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 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 lock(cs_rng_state); @@ -361,3 +424,8 @@ FastRandomContext::FastRandomContext(bool fDeterministic) : requires_seed(!fDete uint256 seed; rng.SetKey(seed.begin(), 32); } + +void RandomInit() +{ + RDRandInit(); +} diff --git a/src/random.h b/src/random.h index 6a63d5742..0c98041c4 100644 --- a/src/random.h +++ b/src/random.h @@ -134,4 +134,7 @@ void GetOSRand(unsigned char *ent32); */ bool Random_SanityCheck(); +/** Initialize the RNG. */ +void RandomInit(); + #endif // BITCOIN_RANDOM_H diff --git a/src/test/test_bitcoin.cpp b/src/test/test_bitcoin.cpp index cb625bda1..3691f8bf5 100644 --- a/src/test/test_bitcoin.cpp +++ b/src/test/test_bitcoin.cpp @@ -35,6 +35,7 @@ extern void noui_connect(); BasicTestingSetup::BasicTestingSetup(const std::string& chainName) { + RandomInit(); ECC_Start(); SetupEnvironment(); SetupNetworking();