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// Typical shadow mapping on Linux/x86_64 with SHADOW_OFFSET == 0x00007fff8000: 23// || `[0x10007fff8000, 0x7fffffffffff]` || HighMem || 24// || `[0x02008fff7000, 0x10007fff7fff]` || HighShadow || 25// || `[0x00008fff7000, 0x02008fff6fff]` || ShadowGap || 26// || `[0x00007fff8000, 0x00008fff6fff]` || LowShadow || 27// || `[0x000000000000, 0x00007fff7fff]` || LowMem || 28// 29// When SHADOW_OFFSET is zero (-pie): 30// || `[0x100000000000, 0x7fffffffffff]` || HighMem || 31// || `[0x020000000000, 0x0fffffffffff]` || HighShadow || 32// || `[0x000000040000, 0x01ffffffffff]` || ShadowGap || 33// 34// Special case when something is already mapped between 35// 0x003000000000 and 0x005000000000 (e.g. when prelink is installed): 36// || `[0x10007fff8000, 0x7fffffffffff]` || HighMem || 37// || `[0x02008fff7000, 0x10007fff7fff]` || HighShadow || 38// || `[0x005000000000, 0x02008fff6fff]` || ShadowGap3 || 39// || `[0x003000000000, 0x004fffffffff]` || MidMem || 40// || `[0x000a7fff8000, 0x002fffffffff]` || ShadowGap2 || 41// || `[0x00067fff8000, 0x000a7fff7fff]` || MidShadow || 42// || `[0x00008fff7000, 0x00067fff7fff]` || ShadowGap || 43// || `[0x00007fff8000, 0x00008fff6fff]` || LowShadow || 44// || `[0x000000000000, 0x00007fff7fff]` || LowMem || 45// 46// Default Linux/i386 mapping: 47// || `[0x40000000, 0xffffffff]` || HighMem || 48// || `[0x28000000, 0x3fffffff]` || HighShadow || 49// || `[0x24000000, 0x27ffffff]` || ShadowGap || 50// || `[0x20000000, 0x23ffffff]` || LowShadow || 51// || `[0x00000000, 0x1fffffff]` || LowMem || 52 53#if ASAN_FLEXIBLE_MAPPING_AND_OFFSET == 1 54extern SANITIZER_INTERFACE_ATTRIBUTE uptr __asan_mapping_scale; 55extern SANITIZER_INTERFACE_ATTRIBUTE uptr __asan_mapping_offset; 56# define SHADOW_SCALE (__asan_mapping_scale) 57# define SHADOW_OFFSET (__asan_mapping_offset) 58#else 59# if ASAN_ANDROID 60# define SHADOW_SCALE (3) 61# define SHADOW_OFFSET (0) 62# else 63# define SHADOW_SCALE (3) 64# if SANITIZER_WORDSIZE == 32 65# define SHADOW_OFFSET (1 << 29) 66# else 67# if defined(__powerpc64__) 68# define SHADOW_OFFSET (1ULL << 41) 69# else 70# if ASAN_MAC 71# define SHADOW_OFFSET (1ULL << 44) 72# else 73# define SHADOW_OFFSET 0x7fff8000ULL 74# endif 75# endif 76# endif 77# endif 78#endif // ASAN_FLEXIBLE_MAPPING_AND_OFFSET 79 80#define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE) 81#define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) + (SHADOW_OFFSET)) 82#define SHADOW_TO_MEM(shadow) (((shadow) - SHADOW_OFFSET) << SHADOW_SCALE) 83 84#define kLowMemBeg 0 85#define kLowMemEnd (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0) 86 87#define kLowShadowBeg SHADOW_OFFSET 88#define kLowShadowEnd MEM_TO_SHADOW(kLowMemEnd) 89 90#define kHighMemBeg (MEM_TO_SHADOW(kHighMemEnd) + 1) 91 92#define kHighShadowBeg MEM_TO_SHADOW(kHighMemBeg) 93#define kHighShadowEnd MEM_TO_SHADOW(kHighMemEnd) 94 95# define kMidShadowBeg MEM_TO_SHADOW(kMidMemBeg) 96# define kMidShadowEnd MEM_TO_SHADOW(kMidMemEnd) 97 98// With the zero shadow base we can not actually map pages starting from 0. 99// This constant is somewhat arbitrary. 100#define kZeroBaseShadowStart (1 << 18) 101 102#define kShadowGapBeg (kLowShadowEnd ? kLowShadowEnd + 1 \ 103 : kZeroBaseShadowStart) 104#define kShadowGapEnd ((kMidMemBeg ? kMidShadowBeg : kHighShadowBeg) - 1) 105 106#define kShadowGap2Beg (kMidMemBeg ? kMidShadowEnd + 1 : 0) 107#define kShadowGap2End (kMidMemBeg ? kMidMemBeg - 1 : 0) 108 109#define kShadowGap3Beg (kMidMemBeg ? kMidMemEnd + 1 : 0) 110#define kShadowGap3End (kMidMemBeg ? kHighShadowBeg - 1 : 0) 111 112#define DO_ASAN_MAPPING_PROFILE 0 // Set to 1 to profile the functions below. 113 114#if DO_ASAN_MAPPING_PROFILE 115# define PROFILE_ASAN_MAPPING() AsanMappingProfile[__LINE__]++; 116#else 117# define PROFILE_ASAN_MAPPING() 118#endif 119 120// If 1, all shadow boundaries are constants. 121// Don't set to 1 other than for testing. 122#define ASAN_FIXED_MAPPING 0 123 124namespace __asan { 125 126extern uptr AsanMappingProfile[]; 127 128#if ASAN_FIXED_MAPPING 129// Fixed mapping for 64-bit Linux. Mostly used for performance comparison 130// with non-fixed mapping. As of r175253 (Feb 2013) the performance 131// difference between fixed and non-fixed mapping is below the noise level. 132static uptr kHighMemEnd = 0x7fffffffffffULL; 133static uptr kMidMemBeg = 0x3000000000ULL; 134static uptr kMidMemEnd = 0x4fffffffffULL; 135#else 136SANITIZER_INTERFACE_ATTRIBUTE 137extern uptr kHighMemEnd, kMidMemBeg, kMidMemEnd; // Initialized in __asan_init. 138#endif 139 140static inline bool AddrIsInLowMem(uptr a) { 141 PROFILE_ASAN_MAPPING(); 142 return a < kLowMemEnd; 143} 144 145static inline bool AddrIsInLowShadow(uptr a) { 146 PROFILE_ASAN_MAPPING(); 147 return a >= kLowShadowBeg && a <= kLowShadowEnd; 148} 149 150static inline bool AddrIsInHighMem(uptr a) { 151 PROFILE_ASAN_MAPPING(); 152 return a >= kHighMemBeg && a <= kHighMemEnd; 153} 154 155static inline bool AddrIsInMidMem(uptr a) { 156 PROFILE_ASAN_MAPPING(); 157 return kMidMemBeg && a >= kMidMemBeg && a <= kMidMemEnd; 158} 159 160static inline bool AddrIsInMem(uptr a) { 161 PROFILE_ASAN_MAPPING(); 162 return AddrIsInLowMem(a) || AddrIsInMidMem(a) || AddrIsInHighMem(a); 163} 164 165static inline uptr MemToShadow(uptr p) { 166 PROFILE_ASAN_MAPPING(); 167 CHECK(AddrIsInMem(p)); 168 return MEM_TO_SHADOW(p); 169} 170 171static inline bool AddrIsInHighShadow(uptr a) { 172 PROFILE_ASAN_MAPPING(); 173 return a >= kHighShadowBeg && a <= kHighMemEnd; 174} 175 176static inline bool AddrIsInMidShadow(uptr a) { 177 PROFILE_ASAN_MAPPING(); 178 return kMidMemBeg && a >= kMidShadowBeg && a <= kMidMemEnd; 179} 180 181static inline bool AddrIsInShadow(uptr a) { 182 PROFILE_ASAN_MAPPING(); 183 return AddrIsInLowShadow(a) || AddrIsInMidShadow(a) || AddrIsInHighShadow(a); 184} 185 186static inline bool AddrIsInShadowGap(uptr a) { 187 PROFILE_ASAN_MAPPING(); 188 if (kMidMemBeg) { 189 if (a <= kShadowGapEnd) 190 return SHADOW_OFFSET == 0 || a >= kShadowGapBeg; 191 return (a >= kShadowGap2Beg && a <= kShadowGap2End) || 192 (a >= kShadowGap3Beg && a <= kShadowGap3End); 193 } 194 // In zero-based shadow mode we treat addresses near zero as addresses 195 // in shadow gap as well. 196 if (SHADOW_OFFSET == 0) 197 return a <= kShadowGapEnd; 198 return a >= kShadowGapBeg && a <= kShadowGapEnd; 199} 200 201static inline bool AddrIsAlignedByGranularity(uptr a) { 202 PROFILE_ASAN_MAPPING(); 203 return (a & (SHADOW_GRANULARITY - 1)) == 0; 204} 205 206static inline bool AddressIsPoisoned(uptr a) { 207 PROFILE_ASAN_MAPPING(); 208 const uptr kAccessSize = 1; 209 u8 *shadow_address = (u8*)MEM_TO_SHADOW(a); 210 s8 shadow_value = *shadow_address; 211 if (shadow_value) { 212 u8 last_accessed_byte = (a & (SHADOW_GRANULARITY - 1)) 213 + kAccessSize - 1; 214 return (last_accessed_byte >= shadow_value); 215 } 216 return false; 217} 218 219// Must be after all calls to PROFILE_ASAN_MAPPING(). 220static const uptr kAsanMappingProfileSize = __LINE__; 221 222} // namespace __asan 223 224#endif // ASAN_MAPPING_H 225