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/MIPS32 mapping: 63 // || `[0x2aaa0000, 0xffffffff]` || HighMem || 64 // || `[0x0fff4000, 0x2aa9ffff]` || HighShadow || 65 // || `[0x0bff4000, 0x0fff3fff]` || ShadowGap || 66 // || `[0x0aaa0000, 0x0bff3fff]` || LowShadow || 67 // || `[0x00000000, 0x0aa9ffff]` || LowMem || 68 // 69 // Default Linux/MIPS64 mapping: 70 // || `[0x4000000000, 0xffffffffff]` || HighMem || 71 // || `[0x2800000000, 0x3fffffffff]` || HighShadow || 72 // || `[0x2400000000, 0x27ffffffff]` || ShadowGap || 73 // || `[0x2000000000, 0x23ffffffff]` || LowShadow || 74 // || `[0x0000000000, 0x1fffffffff]` || LowMem || 75 // 76 // Shadow mapping on FreeBSD/x86-64 with SHADOW_OFFSET == 0x400000000000: 77 // || `[0x500000000000, 0x7fffffffffff]` || HighMem || 78 // || `[0x4a0000000000, 0x4fffffffffff]` || HighShadow || 79 // || `[0x480000000000, 0x49ffffffffff]` || ShadowGap || 80 // || `[0x400000000000, 0x47ffffffffff]` || LowShadow || 81 // || `[0x000000000000, 0x3fffffffffff]` || LowMem || 82 // 83 // Shadow mapping on FreeBSD/i386 with SHADOW_OFFSET == 0x40000000: 84 // || `[0x60000000, 0xffffffff]` || HighMem || 85 // || `[0x4c000000, 0x5fffffff]` || HighShadow || 86 // || `[0x48000000, 0x4bffffff]` || ShadowGap || 87 // || `[0x40000000, 0x47ffffff]` || LowShadow || 88 // || `[0x00000000, 0x3fffffff]` || LowMem || 89 // 90 // Default Windows/i386 mapping: 91 // (the exact location of HighShadow/HighMem may vary depending 92 // on WoW64, /LARGEADDRESSAWARE, etc). 93 // || `[0x50000000, 0xffffffff]` || HighMem || 94 // || `[0x3a000000, 0x4fffffff]` || HighShadow || 95 // || `[0x36000000, 0x39ffffff]` || ShadowGap || 96 // || `[0x30000000, 0x35ffffff]` || LowShadow || 97 // || `[0x00000000, 0x2fffffff]` || LowMem || 98 99 static const u64 kDefaultShadowScale = 3; 100 static const u64 kDefaultShadowOffset32 = 1ULL << 29; // 0x20000000 101 static const u64 kIosShadowOffset32 = 1ULL << 30; // 0x40000000 102 static const u64 kDefaultShadowOffset64 = 1ULL << 44; 103 static const u64 kDefaultShort64bitShadowOffset = 0x7FFF8000; // < 2G. 104 static const u64 kAArch64_ShadowOffset64 = 1ULL << 36; 105 static const u64 kMIPS32_ShadowOffset32 = 0x0aaa0000; 106 static const u64 kMIPS64_ShadowOffset64 = 1ULL << 37; 107 static const u64 kPPC64_ShadowOffset64 = 1ULL << 41; 108 static const u64 kFreeBSD_ShadowOffset32 = 1ULL << 30; // 0x40000000 109 static const u64 kFreeBSD_ShadowOffset64 = 1ULL << 46; // 0x400000000000 110 static const u64 kWindowsShadowOffset32 = 3ULL << 28; // 0x30000000 111 112 #define SHADOW_SCALE kDefaultShadowScale 113 #if SANITIZER_ANDROID 114 # define SHADOW_OFFSET (0) 115 #else 116 # if SANITIZER_WORDSIZE == 32 117 # if defined(__mips__) 118 # define SHADOW_OFFSET kMIPS32_ShadowOffset32 119 # elif SANITIZER_FREEBSD 120 # define SHADOW_OFFSET kFreeBSD_ShadowOffset32 121 # elif SANITIZER_IOS 122 # define SHADOW_OFFSET kIosShadowOffset32 123 # elif SANITIZER_WINDOWS 124 # define SHADOW_OFFSET kWindowsShadowOffset32 125 # else 126 # define SHADOW_OFFSET kDefaultShadowOffset32 127 # endif 128 # else 129 # if defined(__aarch64__) 130 # define SHADOW_OFFSET kAArch64_ShadowOffset64 131 # elif defined(__powerpc64__) 132 # define SHADOW_OFFSET kPPC64_ShadowOffset64 133 # elif SANITIZER_FREEBSD 134 # define SHADOW_OFFSET kFreeBSD_ShadowOffset64 135 # elif SANITIZER_MAC 136 # define SHADOW_OFFSET kDefaultShadowOffset64 137 # elif defined(__mips64) 138 # define SHADOW_OFFSET kMIPS64_ShadowOffset64 139 # else 140 # define SHADOW_OFFSET kDefaultShort64bitShadowOffset 141 # endif 142 # endif 143 #endif 144 145 #define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE) 146 #define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) + (SHADOW_OFFSET)) 147 #define SHADOW_TO_MEM(shadow) (((shadow) - SHADOW_OFFSET) << SHADOW_SCALE) 148 149 #define kLowMemBeg 0 150 #define kLowMemEnd (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0) 151 152 #define kLowShadowBeg SHADOW_OFFSET 153 #define kLowShadowEnd MEM_TO_SHADOW(kLowMemEnd) 154 155 #define kHighMemBeg (MEM_TO_SHADOW(kHighMemEnd) + 1) 156 157 #define kHighShadowBeg MEM_TO_SHADOW(kHighMemBeg) 158 #define kHighShadowEnd MEM_TO_SHADOW(kHighMemEnd) 159 160 # define kMidShadowBeg MEM_TO_SHADOW(kMidMemBeg) 161 # define kMidShadowEnd MEM_TO_SHADOW(kMidMemEnd) 162 163 // With the zero shadow base we can not actually map pages starting from 0. 164 // This constant is somewhat arbitrary. 165 #define kZeroBaseShadowStart (1 << 18) 166 167 #define kShadowGapBeg (kLowShadowEnd ? kLowShadowEnd + 1 \ 168 : kZeroBaseShadowStart) 169 #define kShadowGapEnd ((kMidMemBeg ? kMidShadowBeg : kHighShadowBeg) - 1) 170 171 #define kShadowGap2Beg (kMidMemBeg ? kMidShadowEnd + 1 : 0) 172 #define kShadowGap2End (kMidMemBeg ? kMidMemBeg - 1 : 0) 173 174 #define kShadowGap3Beg (kMidMemBeg ? kMidMemEnd + 1 : 0) 175 #define kShadowGap3End (kMidMemBeg ? kHighShadowBeg - 1 : 0) 176 177 #define DO_ASAN_MAPPING_PROFILE 0 // Set to 1 to profile the functions below. 178 179 #if DO_ASAN_MAPPING_PROFILE 180 # define PROFILE_ASAN_MAPPING() AsanMappingProfile[__LINE__]++; 181 #else 182 # define PROFILE_ASAN_MAPPING() 183 #endif 184 185 // If 1, all shadow boundaries are constants. 186 // Don't set to 1 other than for testing. 187 #define ASAN_FIXED_MAPPING 0 188 189 namespace __asan { 190 191 extern uptr AsanMappingProfile[]; 192 193 #if ASAN_FIXED_MAPPING 194 // Fixed mapping for 64-bit Linux. Mostly used for performance comparison 195 // with non-fixed mapping. As of r175253 (Feb 2013) the performance 196 // difference between fixed and non-fixed mapping is below the noise level. 197 static uptr kHighMemEnd = 0x7fffffffffffULL; 198 static uptr kMidMemBeg = 0x3000000000ULL; 199 static uptr kMidMemEnd = 0x4fffffffffULL; 200 #else 201 extern uptr kHighMemEnd, kMidMemBeg, kMidMemEnd; // Initialized in __asan_init. 202 #endif 203 204 static inline bool AddrIsInLowMem(uptr a) { 205 PROFILE_ASAN_MAPPING(); 206 return a < kLowMemEnd; 207 } 208 209 static inline bool AddrIsInLowShadow(uptr a) { 210 PROFILE_ASAN_MAPPING(); 211 return a >= kLowShadowBeg && a <= kLowShadowEnd; 212 } 213 214 static inline bool AddrIsInHighMem(uptr a) { 215 PROFILE_ASAN_MAPPING(); 216 return a >= kHighMemBeg && a <= kHighMemEnd; 217 } 218 219 static inline bool AddrIsInMidMem(uptr a) { 220 PROFILE_ASAN_MAPPING(); 221 return kMidMemBeg && a >= kMidMemBeg && a <= kMidMemEnd; 222 } 223 224 static inline bool AddrIsInMem(uptr a) { 225 PROFILE_ASAN_MAPPING(); 226 return AddrIsInLowMem(a) || AddrIsInMidMem(a) || AddrIsInHighMem(a); 227 } 228 229 static inline uptr MemToShadow(uptr p) { 230 PROFILE_ASAN_MAPPING(); 231 CHECK(AddrIsInMem(p)); 232 return MEM_TO_SHADOW(p); 233 } 234 235 static inline bool AddrIsInHighShadow(uptr a) { 236 PROFILE_ASAN_MAPPING(); 237 return a >= kHighShadowBeg && a <= kHighMemEnd; 238 } 239 240 static inline bool AddrIsInMidShadow(uptr a) { 241 PROFILE_ASAN_MAPPING(); 242 return kMidMemBeg && a >= kMidShadowBeg && a <= kMidMemEnd; 243 } 244 245 static inline bool AddrIsInShadow(uptr a) { 246 PROFILE_ASAN_MAPPING(); 247 return AddrIsInLowShadow(a) || AddrIsInMidShadow(a) || AddrIsInHighShadow(a); 248 } 249 250 static inline bool AddrIsInShadowGap(uptr a) { 251 PROFILE_ASAN_MAPPING(); 252 if (kMidMemBeg) { 253 if (a <= kShadowGapEnd) 254 return SHADOW_OFFSET == 0 || a >= kShadowGapBeg; 255 return (a >= kShadowGap2Beg && a <= kShadowGap2End) || 256 (a >= kShadowGap3Beg && a <= kShadowGap3End); 257 } 258 // In zero-based shadow mode we treat addresses near zero as addresses 259 // in shadow gap as well. 260 if (SHADOW_OFFSET == 0) 261 return a <= kShadowGapEnd; 262 return a >= kShadowGapBeg && a <= kShadowGapEnd; 263 } 264 265 static inline bool AddrIsAlignedByGranularity(uptr a) { 266 PROFILE_ASAN_MAPPING(); 267 return (a & (SHADOW_GRANULARITY - 1)) == 0; 268 } 269 270 static inline bool AddressIsPoisoned(uptr a) { 271 PROFILE_ASAN_MAPPING(); 272 const uptr kAccessSize = 1; 273 u8 *shadow_address = (u8*)MEM_TO_SHADOW(a); 274 s8 shadow_value = *shadow_address; 275 if (shadow_value) { 276 u8 last_accessed_byte = (a & (SHADOW_GRANULARITY - 1)) 277 + kAccessSize - 1; 278 return (last_accessed_byte >= shadow_value); 279 } 280 return false; 281 } 282 283 // Must be after all calls to PROFILE_ASAN_MAPPING(). 284 static const uptr kAsanMappingProfileSize = __LINE__; 285 286 } // namespace __asan 287 288 #endif // ASAN_MAPPING_H 289
