1 // Copyright 2017 PDFium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com 6 7 #include "core/fxcrt/fx_random.h" 8 9 #include "core/fxcrt/fx_memory.h" 10 #include "core/fxcrt/fx_string.h" 11 #include "core/fxcrt/fx_system.h" 12 13 #define MT_N 848 14 #define MT_M 456 15 #define MT_Matrix_A 0x9908b0df 16 #define MT_Upper_Mask 0x80000000 17 #define MT_Lower_Mask 0x7fffffff 18 19 #if _FX_PLATFORM_ == _FX_PLATFORM_WINDOWS_ 20 #include <wincrypt.h> 21 #else // _FX_PLATFORM_ == _FX_PLATFORM_WINDOWS_ 22 #include <sys/time.h> 23 #include <unistd.h> 24 #endif // _FX_PLATFORM_ == _FX_PLATFORM_WINDOWS_ 25 26 namespace { 27 28 struct MTContext { 29 uint32_t mti; 30 uint32_t mt[MT_N]; 31 }; 32 33 bool g_bHaveGlobalSeed = false; 34 uint32_t g_nGlobalSeed = 0; 35 36 #if _FX_PLATFORM_ == _FX_PLATFORM_WINDOWS_ 37 bool GenerateSeedFromCryptoRandom(uint32_t* pSeed) { 38 HCRYPTPROV hCP = 0; 39 if (!::CryptAcquireContext(&hCP, nullptr, nullptr, PROV_RSA_FULL, 0) || 40 !hCP) { 41 return false; 42 } 43 ::CryptGenRandom(hCP, sizeof(uint32_t), reinterpret_cast<uint8_t*>(pSeed)); 44 ::CryptReleaseContext(hCP, 0); 45 return true; 46 } 47 #endif 48 49 uint32_t GenerateSeedFromEnvironment() { 50 char c; 51 uintptr_t p = reinterpret_cast<uintptr_t>(&c); 52 uint32_t seed = ~static_cast<uint32_t>(p >> 3); 53 #if _FX_PLATFORM_ == _FX_PLATFORM_WINDOWS_ 54 SYSTEMTIME st; 55 GetSystemTime(&st); 56 seed ^= static_cast<uint32_t>(st.wSecond) * 1000000; 57 seed ^= static_cast<uint32_t>(st.wMilliseconds) * 1000; 58 seed ^= GetCurrentProcessId(); 59 #else // _FX_PLATFORM_ == _FX_PLATFORM_WINDOWS_ 60 struct timeval tv; 61 gettimeofday(&tv, 0); 62 seed ^= static_cast<uint32_t>(tv.tv_sec) * 1000000; 63 seed ^= static_cast<uint32_t>(tv.tv_usec); 64 seed ^= static_cast<uint32_t>(getpid()); 65 #endif // _FX_PLATFORM_ == _FX_PLATFORM_WINDOWS_ 66 return seed; 67 } 68 69 void* ContextFromNextGlobalSeed() { 70 if (!g_bHaveGlobalSeed) { 71 #if _FX_PLATFORM_ == _FX_PLATFORM_WINDOWS_ 72 if (!GenerateSeedFromCryptoRandom(&g_nGlobalSeed)) 73 g_nGlobalSeed = GenerateSeedFromEnvironment(); 74 #else // _FX_PLATFORM_ == _FX_PLATFORM_WINDOWS_ 75 g_nGlobalSeed = GenerateSeedFromEnvironment(); 76 #endif // _FX_PLATFORM_ == _FX_PLATFORM_WINDOWS_ 77 g_bHaveGlobalSeed = true; 78 } 79 return FX_Random_MT_Start(++g_nGlobalSeed); 80 } 81 82 } // namespace 83 84 void* FX_Random_MT_Start(uint32_t dwSeed) { 85 MTContext* pContext = FX_Alloc(MTContext, 1); 86 uint32_t* pBuf = pContext->mt; 87 pBuf[0] = dwSeed; 88 for (uint32_t i = 1; i < MT_N; i++) 89 pBuf[i] = (1812433253UL * (pBuf[i - 1] ^ (pBuf[i - 1] >> 30)) + i); 90 91 pContext->mti = MT_N; 92 return pContext; 93 } 94 95 uint32_t FX_Random_MT_Generate(void* pContext) { 96 MTContext* pMTC = static_cast<MTContext*>(pContext); 97 uint32_t* pBuf = pMTC->mt; 98 uint32_t v; 99 if (pMTC->mti >= MT_N) { 100 static const uint32_t mag[2] = {0, MT_Matrix_A}; 101 uint32_t kk; 102 for (kk = 0; kk < MT_N - MT_M; kk++) { 103 v = (pBuf[kk] & MT_Upper_Mask) | (pBuf[kk + 1] & MT_Lower_Mask); 104 pBuf[kk] = pBuf[kk + MT_M] ^ (v >> 1) ^ mag[v & 1]; 105 } 106 for (; kk < MT_N - 1; kk++) { 107 v = (pBuf[kk] & MT_Upper_Mask) | (pBuf[kk + 1] & MT_Lower_Mask); 108 pBuf[kk] = pBuf[kk + (MT_M - MT_N)] ^ (v >> 1) ^ mag[v & 1]; 109 } 110 v = (pBuf[MT_N - 1] & MT_Upper_Mask) | (pBuf[0] & MT_Lower_Mask); 111 pBuf[MT_N - 1] = pBuf[MT_M - 1] ^ (v >> 1) ^ mag[v & 1]; 112 pMTC->mti = 0; 113 } 114 v = pBuf[pMTC->mti++]; 115 v ^= (v >> 11); 116 v ^= (v << 7) & 0x9d2c5680UL; 117 v ^= (v << 15) & 0xefc60000UL; 118 v ^= (v >> 18); 119 return v; 120 } 121 122 void FX_Random_MT_Close(void* pContext) { 123 FX_Free(pContext); 124 } 125 126 void FX_Random_GenerateMT(uint32_t* pBuffer, int32_t iCount) { 127 void* pContext = ContextFromNextGlobalSeed(); 128 while (iCount-- > 0) 129 *pBuffer++ = FX_Random_MT_Generate(pContext); 130 131 FX_Random_MT_Close(pContext); 132 } 133
