1 //===-- asan_mapping.h ------------------------------------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file is a part of AddressSanitizer, an address sanity checker. 11 // 12 // Defines ASan memory mapping. 13 //===----------------------------------------------------------------------===// 14 #ifndef ASAN_MAPPING_H 15 #define ASAN_MAPPING_H 16 17 #include "asan_internal.h" 18 19 // The full explanation of the memory mapping could be found here: 20 // http://code.google.com/p/address-sanitizer/wiki/AddressSanitizerAlgorithm 21 22 #if ASAN_FLEXIBLE_MAPPING_AND_OFFSET == 1 23 extern __attribute__((visibility("default"))) uintptr_t __asan_mapping_scale; 24 extern __attribute__((visibility("default"))) uintptr_t __asan_mapping_offset; 25 # define SHADOW_SCALE (__asan_mapping_scale) 26 # define SHADOW_OFFSET (__asan_mapping_offset) 27 #else 28 # ifdef ANDROID 29 # define SHADOW_SCALE (3) 30 # define SHADOW_OFFSET (0) 31 # else 32 # define SHADOW_SCALE (3) 33 # if __WORDSIZE == 32 34 # define SHADOW_OFFSET (1 << 29) 35 # else 36 # define SHADOW_OFFSET (1ULL << 44) 37 # endif 38 # endif 39 #endif // ASAN_FLEXIBLE_MAPPING_AND_OFFSET 40 41 #define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE) 42 #define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) | (SHADOW_OFFSET)) 43 44 #if __WORDSIZE == 64 45 static const size_t kHighMemEnd = 0x00007fffffffffffUL; 46 #else // __WORDSIZE == 32 47 static const size_t kHighMemEnd = 0xffffffff; 48 #endif // __WORDSIZE 49 50 51 #define kLowMemBeg 0 52 #define kLowMemEnd (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0) 53 54 #define kLowShadowBeg SHADOW_OFFSET 55 #define kLowShadowEnd MEM_TO_SHADOW(kLowMemEnd) 56 57 #define kHighMemBeg (MEM_TO_SHADOW(kHighMemEnd) + 1) 58 59 #define kHighShadowBeg MEM_TO_SHADOW(kHighMemBeg) 60 #define kHighShadowEnd MEM_TO_SHADOW(kHighMemEnd) 61 62 #define kShadowGapBeg (kLowShadowEnd ? kLowShadowEnd + 1 : 16 * kPageSize) 63 #define kShadowGapEnd (kHighShadowBeg - 1) 64 65 #define kGlobalAndStackRedzone \ 66 (SHADOW_GRANULARITY < 32 ? 32 : SHADOW_GRANULARITY) 67 68 namespace __asan { 69 70 static inline bool AddrIsInLowMem(uintptr_t a) { 71 return a < kLowMemEnd; 72 } 73 74 static inline bool AddrIsInLowShadow(uintptr_t a) { 75 return a >= kLowShadowBeg && a <= kLowShadowEnd; 76 } 77 78 static inline bool AddrIsInHighMem(uintptr_t a) { 79 return a >= kHighMemBeg && a <= kHighMemEnd; 80 } 81 82 static inline bool AddrIsInMem(uintptr_t a) { 83 return AddrIsInLowMem(a) || AddrIsInHighMem(a); 84 } 85 86 static inline uintptr_t MemToShadow(uintptr_t p) { 87 CHECK(AddrIsInMem(p)); 88 return MEM_TO_SHADOW(p); 89 } 90 91 static inline bool AddrIsInHighShadow(uintptr_t a) { 92 return a >= kHighShadowBeg && a <= kHighMemEnd; 93 } 94 95 static inline bool AddrIsInShadow(uintptr_t a) { 96 return AddrIsInLowShadow(a) || AddrIsInHighShadow(a); 97 } 98 99 static inline bool AddrIsAlignedByGranularity(uintptr_t a) { 100 return (a & (SHADOW_GRANULARITY - 1)) == 0; 101 } 102 103 static inline bool AddressIsPoisoned(uintptr_t a) { 104 const size_t kAccessSize = 1; 105 uint8_t *shadow_address = (uint8_t*)MemToShadow(a); 106 int8_t shadow_value = *shadow_address; 107 if (shadow_value) { 108 uint8_t last_accessed_byte = (a & (SHADOW_GRANULARITY - 1)) 109 + kAccessSize - 1; 110 return (last_accessed_byte >= shadow_value); 111 } 112 return false; 113 } 114 115 } // namespace __asan 116 117 #endif // ASAN_MAPPING_H 118
