asan_mapping.h revision 276789
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// || `[0x2aaa0000, 0xffffffff]` || HighMem || 64// || `[0x0fff4000, 0x2aa9ffff]` || HighShadow || 65// || `[0x0bff4000, 0x0fff3fff]` || ShadowGap || 66// || `[0x0aaa0000, 0x0bff3fff]` || LowShadow || 67// || `[0x00000000, 0x0aa9ffff]` || 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 83static const u64 kDefaultShadowScale = 3; 84static const u64 kDefaultShadowOffset32 = 1ULL << 29; // 0x20000000 85static const u64 kIosShadowOffset32 = 1ULL << 30; // 0x40000000 86static const u64 kDefaultShadowOffset64 = 1ULL << 44; 87static const u64 kDefaultShort64bitShadowOffset = 0x7FFF8000; // < 2G. 88static const u64 kAArch64_ShadowOffset64 = 1ULL << 36; 89static const u64 kMIPS32_ShadowOffset32 = 0x0aaa0000; 90static const u64 kMIPS64_ShadowOffset64 = 1ULL << 36; 91static const u64 kPPC64_ShadowOffset64 = 1ULL << 41; 92static const u64 kFreeBSD_ShadowOffset32 = 1ULL << 30; // 0x40000000 93static const u64 kFreeBSD_ShadowOffset64 = 1ULL << 46; // 0x400000000000 94 95#define SHADOW_SCALE kDefaultShadowScale 96#if SANITIZER_ANDROID 97# define SHADOW_OFFSET (0) 98#else 99# if SANITIZER_WORDSIZE == 32 100# if defined(__mips__) 101# define SHADOW_OFFSET kMIPS32_ShadowOffset32 102# elif SANITIZER_FREEBSD 103# define SHADOW_OFFSET kFreeBSD_ShadowOffset32 104# else 105# if SANITIZER_IOS 106# define SHADOW_OFFSET kIosShadowOffset32 107# else 108# define SHADOW_OFFSET kDefaultShadowOffset32 109# endif 110# endif 111# else 112# if defined(__aarch64__) 113# define SHADOW_OFFSET kAArch64_ShadowOffset64 114# elif defined(__powerpc64__) 115# define SHADOW_OFFSET kPPC64_ShadowOffset64 116# elif SANITIZER_FREEBSD 117# define SHADOW_OFFSET kFreeBSD_ShadowOffset64 118# elif SANITIZER_MAC 119# define SHADOW_OFFSET kDefaultShadowOffset64 120# elif defined(__mips64) 121# define SHADOW_OFFSET kMIPS64_ShadowOffset64 122# else 123# define SHADOW_OFFSET kDefaultShort64bitShadowOffset 124# endif 125# endif 126#endif 127 128#define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE) 129#define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) + (SHADOW_OFFSET)) 130#define SHADOW_TO_MEM(shadow) (((shadow) - SHADOW_OFFSET) << SHADOW_SCALE) 131 132#define kLowMemBeg 0 133#define kLowMemEnd (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0) 134 135#define kLowShadowBeg SHADOW_OFFSET 136#define kLowShadowEnd MEM_TO_SHADOW(kLowMemEnd) 137 138#define kHighMemBeg (MEM_TO_SHADOW(kHighMemEnd) + 1) 139 140#define kHighShadowBeg MEM_TO_SHADOW(kHighMemBeg) 141#define kHighShadowEnd MEM_TO_SHADOW(kHighMemEnd) 142 143# define kMidShadowBeg MEM_TO_SHADOW(kMidMemBeg) 144# define kMidShadowEnd MEM_TO_SHADOW(kMidMemEnd) 145 146// With the zero shadow base we can not actually map pages starting from 0. 147// This constant is somewhat arbitrary. 148#define kZeroBaseShadowStart (1 << 18) 149 150#define kShadowGapBeg (kLowShadowEnd ? kLowShadowEnd + 1 \ 151 : kZeroBaseShadowStart) 152#define kShadowGapEnd ((kMidMemBeg ? kMidShadowBeg : kHighShadowBeg) - 1) 153 154#define kShadowGap2Beg (kMidMemBeg ? kMidShadowEnd + 1 : 0) 155#define kShadowGap2End (kMidMemBeg ? kMidMemBeg - 1 : 0) 156 157#define kShadowGap3Beg (kMidMemBeg ? kMidMemEnd + 1 : 0) 158#define kShadowGap3End (kMidMemBeg ? kHighShadowBeg - 1 : 0) 159 160#define DO_ASAN_MAPPING_PROFILE 0 // Set to 1 to profile the functions below. 161 162#if DO_ASAN_MAPPING_PROFILE 163# define PROFILE_ASAN_MAPPING() AsanMappingProfile[__LINE__]++; 164#else 165# define PROFILE_ASAN_MAPPING() 166#endif 167 168// If 1, all shadow boundaries are constants. 169// Don't set to 1 other than for testing. 170#define ASAN_FIXED_MAPPING 0 171 172namespace __asan { 173 174extern uptr AsanMappingProfile[]; 175 176#if ASAN_FIXED_MAPPING 177// Fixed mapping for 64-bit Linux. Mostly used for performance comparison 178// with non-fixed mapping. As of r175253 (Feb 2013) the performance 179// difference between fixed and non-fixed mapping is below the noise level. 180static uptr kHighMemEnd = 0x7fffffffffffULL; 181static uptr kMidMemBeg = 0x3000000000ULL; 182static uptr kMidMemEnd = 0x4fffffffffULL; 183#else 184extern uptr kHighMemEnd, kMidMemBeg, kMidMemEnd; // Initialized in __asan_init. 185#endif 186 187static inline bool AddrIsInLowMem(uptr a) { 188 PROFILE_ASAN_MAPPING(); 189 return a < kLowMemEnd; 190} 191 192static inline bool AddrIsInLowShadow(uptr a) { 193 PROFILE_ASAN_MAPPING(); 194 return a >= kLowShadowBeg && a <= kLowShadowEnd; 195} 196 197static inline bool AddrIsInHighMem(uptr a) { 198 PROFILE_ASAN_MAPPING(); 199 return a >= kHighMemBeg && a <= kHighMemEnd; 200} 201 202static inline bool AddrIsInMidMem(uptr a) { 203 PROFILE_ASAN_MAPPING(); 204 return kMidMemBeg && a >= kMidMemBeg && a <= kMidMemEnd; 205} 206 207static inline bool AddrIsInMem(uptr a) { 208 PROFILE_ASAN_MAPPING(); 209 return AddrIsInLowMem(a) || AddrIsInMidMem(a) || AddrIsInHighMem(a); 210} 211 212static inline uptr MemToShadow(uptr p) { 213 PROFILE_ASAN_MAPPING(); 214 CHECK(AddrIsInMem(p)); 215 return MEM_TO_SHADOW(p); 216} 217 218static inline bool AddrIsInHighShadow(uptr a) { 219 PROFILE_ASAN_MAPPING(); 220 return a >= kHighShadowBeg && a <= kHighMemEnd; 221} 222 223static inline bool AddrIsInMidShadow(uptr a) { 224 PROFILE_ASAN_MAPPING(); 225 return kMidMemBeg && a >= kMidShadowBeg && a <= kMidMemEnd; 226} 227 228static inline bool AddrIsInShadow(uptr a) { 229 PROFILE_ASAN_MAPPING(); 230 return AddrIsInLowShadow(a) || AddrIsInMidShadow(a) || AddrIsInHighShadow(a); 231} 232 233static inline bool AddrIsInShadowGap(uptr a) { 234 PROFILE_ASAN_MAPPING(); 235 if (kMidMemBeg) { 236 if (a <= kShadowGapEnd) 237 return SHADOW_OFFSET == 0 || a >= kShadowGapBeg; 238 return (a >= kShadowGap2Beg && a <= kShadowGap2End) || 239 (a >= kShadowGap3Beg && a <= kShadowGap3End); 240 } 241 // In zero-based shadow mode we treat addresses near zero as addresses 242 // in shadow gap as well. 243 if (SHADOW_OFFSET == 0) 244 return a <= kShadowGapEnd; 245 return a >= kShadowGapBeg && a <= kShadowGapEnd; 246} 247 248static inline bool AddrIsAlignedByGranularity(uptr a) { 249 PROFILE_ASAN_MAPPING(); 250 return (a & (SHADOW_GRANULARITY - 1)) == 0; 251} 252 253static inline bool AddressIsPoisoned(uptr a) { 254 PROFILE_ASAN_MAPPING(); 255 const uptr kAccessSize = 1; 256 u8 *shadow_address = (u8*)MEM_TO_SHADOW(a); 257 s8 shadow_value = *shadow_address; 258 if (shadow_value) { 259 u8 last_accessed_byte = (a & (SHADOW_GRANULARITY - 1)) 260 + kAccessSize - 1; 261 return (last_accessed_byte >= shadow_value); 262 } 263 return false; 264} 265 266// Must be after all calls to PROFILE_ASAN_MAPPING(). 267static const uptr kAsanMappingProfileSize = __LINE__; 268 269} // namespace __asan 270 271#endif // ASAN_MAPPING_H 272