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 on x86_64 machine: 47 // || `[0x40000000, 0xffffffff]` || HighMem || 48 // || `[0x28000000, 0x3fffffff]` || HighShadow || 49 // || `[0x24000000, 0x27ffffff]` || ShadowGap || 50 // || `[0x20000000, 0x23ffffff]` || LowShadow || 51 // || `[0x00000000, 0x1fffffff]` || LowMem || 52 // 53 // Default Linux/i386 mapping on i386 machine 54 // (addresses starting with 0xc0000000 are reserved 55 // for kernel and thus not sanitized): 56 // || `[0x38000000, 0xbfffffff]` || HighMem || 57 // || `[0x27000000, 0x37ffffff]` || HighShadow || 58 // || `[0x24000000, 0x26ffffff]` || ShadowGap || 59 // || `[0x20000000, 0x23ffffff]` || LowShadow || 60 // || `[0x00000000, 0x1fffffff]` || LowMem || 61 // 62 // Default Linux/MIPS mapping: 63 // || `[0x2aaa8000, 0xffffffff]` || HighMem || 64 // || `[0x0fffd000, 0x2aaa7fff]` || HighShadow || 65 // || `[0x0bffd000, 0x0fffcfff]` || ShadowGap || 66 // || `[0x0aaa8000, 0x0bffcfff]` || LowShadow || 67 // || `[0x00000000, 0x0aaa7fff]` || LowMem || 68 // 69 // Shadow mapping on FreeBSD/x86-64 with SHADOW_OFFSET == 0x400000000000: 70 // || `[0x500000000000, 0x7fffffffffff]` || HighMem || 71 // || `[0x4a0000000000, 0x4fffffffffff]` || HighShadow || 72 // || `[0x480000000000, 0x49ffffffffff]` || ShadowGap || 73 // || `[0x400000000000, 0x47ffffffffff]` || LowShadow || 74 // || `[0x000000000000, 0x3fffffffffff]` || LowMem || 75 // 76 // Shadow mapping on FreeBSD/i386 with SHADOW_OFFSET == 0x40000000: 77 // || `[0x60000000, 0xffffffff]` || HighMem || 78 // || `[0x4c000000, 0x5fffffff]` || HighShadow || 79 // || `[0x48000000, 0x4bffffff]` || ShadowGap || 80 // || `[0x40000000, 0x47ffffff]` || LowShadow || 81 // || `[0x00000000, 0x3fffffff]` || LowMem || 82 83 static const u64 kDefaultShadowScale = 3; 84 static const u64 kDefaultShadowOffset32 = 1ULL << 29; // 0x20000000 85 static const u64 kIosShadowOffset32 = 1ULL << 30; // 0x40000000 86 static const u64 kDefaultShadowOffset64 = 1ULL << 44; 87 static const u64 kDefaultShort64bitShadowOffset = 0x7FFF8000; // < 2G. 88 static const u64 kAArch64_ShadowOffset64 = 1ULL << 36; 89 static const u64 kMIPS32_ShadowOffset32 = 0x0aaa8000; 90 static const u64 kPPC64_ShadowOffset64 = 1ULL << 41; 91 static const u64 kFreeBSD_ShadowOffset32 = 1ULL << 30; // 0x40000000 92 static const u64 kFreeBSD_ShadowOffset64 = 1ULL << 46; // 0x400000000000 93 94 #define SHADOW_SCALE kDefaultShadowScale 95 #if SANITIZER_ANDROID 96 # define SHADOW_OFFSET (0) 97 #else 98 # if SANITIZER_WORDSIZE == 32 99 # if defined(__mips__) 100 # define SHADOW_OFFSET kMIPS32_ShadowOffset32 101 # elif SANITIZER_FREEBSD 102 # define SHADOW_OFFSET kFreeBSD_ShadowOffset32 103 # else 104 # if SANITIZER_IOS 105 # define SHADOW_OFFSET kIosShadowOffset32 106 # else 107 # define SHADOW_OFFSET kDefaultShadowOffset32 108 # endif 109 # endif 110 # else 111 # if defined(__aarch64__) 112 # define SHADOW_OFFSET kAArch64_ShadowOffset64 113 # elif defined(__powerpc64__) 114 # define SHADOW_OFFSET kPPC64_ShadowOffset64 115 # elif SANITIZER_FREEBSD 116 # define SHADOW_OFFSET kFreeBSD_ShadowOffset64 117 # elif SANITIZER_MAC 118 # define SHADOW_OFFSET kDefaultShadowOffset64 119 # else 120 # define SHADOW_OFFSET kDefaultShort64bitShadowOffset 121 # endif 122 # endif 123 #endif 124 125 #define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE) 126 #define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) + (SHADOW_OFFSET)) 127 #define SHADOW_TO_MEM(shadow) (((shadow) - SHADOW_OFFSET) << SHADOW_SCALE) 128 129 #define kLowMemBeg 0 130 #define kLowMemEnd (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0) 131 132 #define kLowShadowBeg SHADOW_OFFSET 133 #define kLowShadowEnd MEM_TO_SHADOW(kLowMemEnd) 134 135 #define kHighMemBeg (MEM_TO_SHADOW(kHighMemEnd) + 1) 136 137 #define kHighShadowBeg MEM_TO_SHADOW(kHighMemBeg) 138 #define kHighShadowEnd MEM_TO_SHADOW(kHighMemEnd) 139 140 # define kMidShadowBeg MEM_TO_SHADOW(kMidMemBeg) 141 # define kMidShadowEnd MEM_TO_SHADOW(kMidMemEnd) 142 143 // With the zero shadow base we can not actually map pages starting from 0. 144 // This constant is somewhat arbitrary. 145 #define kZeroBaseShadowStart (1 << 18) 146 147 #define kShadowGapBeg (kLowShadowEnd ? kLowShadowEnd + 1 \ 148 : kZeroBaseShadowStart) 149 #define kShadowGapEnd ((kMidMemBeg ? kMidShadowBeg : kHighShadowBeg) - 1) 150 151 #define kShadowGap2Beg (kMidMemBeg ? kMidShadowEnd + 1 : 0) 152 #define kShadowGap2End (kMidMemBeg ? kMidMemBeg - 1 : 0) 153 154 #define kShadowGap3Beg (kMidMemBeg ? kMidMemEnd + 1 : 0) 155 #define kShadowGap3End (kMidMemBeg ? kHighShadowBeg - 1 : 0) 156 157 #define DO_ASAN_MAPPING_PROFILE 0 // Set to 1 to profile the functions below. 158 159 #if DO_ASAN_MAPPING_PROFILE 160 # define PROFILE_ASAN_MAPPING() AsanMappingProfile[__LINE__]++; 161 #else 162 # define PROFILE_ASAN_MAPPING() 163 #endif 164 165 // If 1, all shadow boundaries are constants. 166 // Don't set to 1 other than for testing. 167 #define ASAN_FIXED_MAPPING 0 168 169 namespace __asan { 170 171 extern uptr AsanMappingProfile[]; 172 173 #if ASAN_FIXED_MAPPING 174 // Fixed mapping for 64-bit Linux. Mostly used for performance comparison 175 // with non-fixed mapping. As of r175253 (Feb 2013) the performance 176 // difference between fixed and non-fixed mapping is below the noise level. 177 static uptr kHighMemEnd = 0x7fffffffffffULL; 178 static uptr kMidMemBeg = 0x3000000000ULL; 179 static uptr kMidMemEnd = 0x4fffffffffULL; 180 #else 181 extern uptr kHighMemEnd, kMidMemBeg, kMidMemEnd; // Initialized in __asan_init. 182 #endif 183 184 static inline bool AddrIsInLowMem(uptr a) { 185 PROFILE_ASAN_MAPPING(); 186 return a < kLowMemEnd; 187 } 188 189 static inline bool AddrIsInLowShadow(uptr a) { 190 PROFILE_ASAN_MAPPING(); 191 return a >= kLowShadowBeg && a <= kLowShadowEnd; 192 } 193 194 static inline bool AddrIsInHighMem(uptr a) { 195 PROFILE_ASAN_MAPPING(); 196 return a >= kHighMemBeg && a <= kHighMemEnd; 197 } 198 199 static inline bool AddrIsInMidMem(uptr a) { 200 PROFILE_ASAN_MAPPING(); 201 return kMidMemBeg && a >= kMidMemBeg && a <= kMidMemEnd; 202 } 203 204 static inline bool AddrIsInMem(uptr a) { 205 PROFILE_ASAN_MAPPING(); 206 return AddrIsInLowMem(a) || AddrIsInMidMem(a) || AddrIsInHighMem(a); 207 } 208 209 static inline uptr MemToShadow(uptr p) { 210 PROFILE_ASAN_MAPPING(); 211 CHECK(AddrIsInMem(p)); 212 return MEM_TO_SHADOW(p); 213 } 214 215 static inline bool AddrIsInHighShadow(uptr a) { 216 PROFILE_ASAN_MAPPING(); 217 return a >= kHighShadowBeg && a <= kHighMemEnd; 218 } 219 220 static inline bool AddrIsInMidShadow(uptr a) { 221 PROFILE_ASAN_MAPPING(); 222 return kMidMemBeg && a >= kMidShadowBeg && a <= kMidMemEnd; 223 } 224 225 static inline bool AddrIsInShadow(uptr a) { 226 PROFILE_ASAN_MAPPING(); 227 return AddrIsInLowShadow(a) || AddrIsInMidShadow(a) || AddrIsInHighShadow(a); 228 } 229 230 static inline bool AddrIsInShadowGap(uptr a) { 231 PROFILE_ASAN_MAPPING(); 232 if (kMidMemBeg) { 233 if (a <= kShadowGapEnd) 234 return SHADOW_OFFSET == 0 || a >= kShadowGapBeg; 235 return (a >= kShadowGap2Beg && a <= kShadowGap2End) || 236 (a >= kShadowGap3Beg && a <= kShadowGap3End); 237 } 238 // In zero-based shadow mode we treat addresses near zero as addresses 239 // in shadow gap as well. 240 if (SHADOW_OFFSET == 0) 241 return a <= kShadowGapEnd; 242 return a >= kShadowGapBeg && a <= kShadowGapEnd; 243 } 244 245 static inline bool AddrIsAlignedByGranularity(uptr a) { 246 PROFILE_ASAN_MAPPING(); 247 return (a & (SHADOW_GRANULARITY - 1)) == 0; 248 } 249 250 static inline bool AddressIsPoisoned(uptr a) { 251 PROFILE_ASAN_MAPPING(); 252 const uptr kAccessSize = 1; 253 u8 *shadow_address = (u8*)MEM_TO_SHADOW(a); 254 s8 shadow_value = *shadow_address; 255 if (shadow_value) { 256 u8 last_accessed_byte = (a & (SHADOW_GRANULARITY - 1)) 257 + kAccessSize - 1; 258 return (last_accessed_byte >= shadow_value); 259 } 260 return false; 261 } 262 263 // Must be after all calls to PROFILE_ASAN_MAPPING(). 264 static const uptr kAsanMappingProfileSize = __LINE__; 265 266 } // namespace __asan 267 268 #endif // ASAN_MAPPING_H 269
