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 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 = 0x0aaa8000; 90static const u64 kPPC64_ShadowOffset64 = 1ULL << 41; 91static const u64 kFreeBSD_ShadowOffset32 = 1ULL << 30; // 0x40000000 92static 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 169namespace __asan { 170 171extern 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. 177static uptr kHighMemEnd = 0x7fffffffffffULL; 178static uptr kMidMemBeg = 0x3000000000ULL; 179static uptr kMidMemEnd = 0x4fffffffffULL; 180#else 181extern uptr kHighMemEnd, kMidMemBeg, kMidMemEnd; // Initialized in __asan_init. 182#endif 183 184static inline bool AddrIsInLowMem(uptr a) { 185 PROFILE_ASAN_MAPPING(); 186 return a < kLowMemEnd; 187} 188 189static inline bool AddrIsInLowShadow(uptr a) { 190 PROFILE_ASAN_MAPPING(); 191 return a >= kLowShadowBeg && a <= kLowShadowEnd; 192} 193 194static inline bool AddrIsInHighMem(uptr a) { 195 PROFILE_ASAN_MAPPING(); 196 return a >= kHighMemBeg && a <= kHighMemEnd; 197} 198 199static inline bool AddrIsInMidMem(uptr a) { 200 PROFILE_ASAN_MAPPING(); 201 return kMidMemBeg && a >= kMidMemBeg && a <= kMidMemEnd; 202} 203 204static inline bool AddrIsInMem(uptr a) { 205 PROFILE_ASAN_MAPPING(); 206 return AddrIsInLowMem(a) || AddrIsInMidMem(a) || AddrIsInHighMem(a); 207} 208 209static inline uptr MemToShadow(uptr p) { 210 PROFILE_ASAN_MAPPING(); 211 CHECK(AddrIsInMem(p)); 212 return MEM_TO_SHADOW(p); 213} 214 215static inline bool AddrIsInHighShadow(uptr a) { 216 PROFILE_ASAN_MAPPING(); 217 return a >= kHighShadowBeg && a <= kHighMemEnd; 218} 219 220static inline bool AddrIsInMidShadow(uptr a) { 221 PROFILE_ASAN_MAPPING(); 222 return kMidMemBeg && a >= kMidShadowBeg && a <= kMidMemEnd; 223} 224 225static inline bool AddrIsInShadow(uptr a) { 226 PROFILE_ASAN_MAPPING(); 227 return AddrIsInLowShadow(a) || AddrIsInMidShadow(a) || AddrIsInHighShadow(a); 228} 229 230static 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 245static inline bool AddrIsAlignedByGranularity(uptr a) { 246 PROFILE_ASAN_MAPPING(); 247 return (a & (SHADOW_GRANULARITY - 1)) == 0; 248} 249 250static 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(). 264static const uptr kAsanMappingProfileSize = __LINE__; 265 266} // namespace __asan 267 268#endif // ASAN_MAPPING_H 269