asan_mapping.h revision 1.7
1//===-- asan_mapping.h ------------------------------------------*- C++ -*-===// 2// 3// This file is distributed under the University of Illinois Open Source 4// License. See LICENSE.TXT for details. 5// 6//===----------------------------------------------------------------------===// 7// 8// This file is a part of AddressSanitizer, an address sanity checker. 9// 10// Defines ASan memory mapping. 11//===----------------------------------------------------------------------===// 12#ifndef ASAN_MAPPING_H 13#define ASAN_MAPPING_H 14 15#include "asan_internal.h" 16 17// The full explanation of the memory mapping could be found here: 18// https://github.com/google/sanitizers/wiki/AddressSanitizerAlgorithm 19// 20// Typical shadow mapping on Linux/x86_64 with SHADOW_OFFSET == 0x00007fff8000: 21// || `[0x10007fff8000, 0x7fffffffffff]` || HighMem || 22// || `[0x02008fff7000, 0x10007fff7fff]` || HighShadow || 23// || `[0x00008fff7000, 0x02008fff6fff]` || ShadowGap || 24// || `[0x00007fff8000, 0x00008fff6fff]` || LowShadow || 25// || `[0x000000000000, 0x00007fff7fff]` || LowMem || 26// 27// When SHADOW_OFFSET is zero (-pie): 28// || `[0x100000000000, 0x7fffffffffff]` || HighMem || 29// || `[0x020000000000, 0x0fffffffffff]` || HighShadow || 30// || `[0x000000040000, 0x01ffffffffff]` || ShadowGap || 31// 32// Special case when something is already mapped between 33// 0x003000000000 and 0x005000000000 (e.g. when prelink is installed): 34// || `[0x10007fff8000, 0x7fffffffffff]` || HighMem || 35// || `[0x02008fff7000, 0x10007fff7fff]` || HighShadow || 36// || `[0x005000000000, 0x02008fff6fff]` || ShadowGap3 || 37// || `[0x003000000000, 0x004fffffffff]` || MidMem || 38// || `[0x000a7fff8000, 0x002fffffffff]` || ShadowGap2 || 39// || `[0x00067fff8000, 0x000a7fff7fff]` || MidShadow || 40// || `[0x00008fff7000, 0x00067fff7fff]` || ShadowGap || 41// || `[0x00007fff8000, 0x00008fff6fff]` || LowShadow || 42// || `[0x000000000000, 0x00007fff7fff]` || LowMem || 43// 44// Default Linux/i386 mapping on x86_64 machine: 45// || `[0x40000000, 0xffffffff]` || HighMem || 46// || `[0x28000000, 0x3fffffff]` || HighShadow || 47// || `[0x24000000, 0x27ffffff]` || ShadowGap || 48// || `[0x20000000, 0x23ffffff]` || LowShadow || 49// || `[0x00000000, 0x1fffffff]` || LowMem || 50// 51// Default Linux/i386 mapping on i386 machine 52// (addresses starting with 0xc0000000 are reserved 53// for kernel and thus not sanitized): 54// || `[0x38000000, 0xbfffffff]` || HighMem || 55// || `[0x27000000, 0x37ffffff]` || HighShadow || 56// || `[0x24000000, 0x26ffffff]` || ShadowGap || 57// || `[0x20000000, 0x23ffffff]` || LowShadow || 58// || `[0x00000000, 0x1fffffff]` || LowMem || 59// 60// Default Linux/MIPS32 mapping: 61// || `[0x2aaa0000, 0xffffffff]` || HighMem || 62// || `[0x0fff4000, 0x2aa9ffff]` || HighShadow || 63// || `[0x0bff4000, 0x0fff3fff]` || ShadowGap || 64// || `[0x0aaa0000, 0x0bff3fff]` || LowShadow || 65// || `[0x00000000, 0x0aa9ffff]` || LowMem || 66// 67// Default Linux/MIPS64 mapping: 68// || `[0x4000000000, 0xffffffffff]` || HighMem || 69// || `[0x2800000000, 0x3fffffffff]` || HighShadow || 70// || `[0x2400000000, 0x27ffffffff]` || ShadowGap || 71// || `[0x2000000000, 0x23ffffffff]` || LowShadow || 72// || `[0x0000000000, 0x1fffffffff]` || LowMem || 73// 74// Default Linux/AArch64 (39-bit VMA) mapping: 75// || `[0x2000000000, 0x7fffffffff]` || highmem || 76// || `[0x1400000000, 0x1fffffffff]` || highshadow || 77// || `[0x1200000000, 0x13ffffffff]` || shadowgap || 78// || `[0x1000000000, 0x11ffffffff]` || lowshadow || 79// || `[0x0000000000, 0x0fffffffff]` || lowmem || 80// 81// Default Linux/AArch64 (42-bit VMA) mapping: 82// || `[0x10000000000, 0x3ffffffffff]` || highmem || 83// || `[0x0a000000000, 0x0ffffffffff]` || highshadow || 84// || `[0x09000000000, 0x09fffffffff]` || shadowgap || 85// || `[0x08000000000, 0x08fffffffff]` || lowshadow || 86// || `[0x00000000000, 0x07fffffffff]` || lowmem || 87// 88// Default Linux/S390 mapping: 89// || `[0x30000000, 0x7fffffff]` || HighMem || 90// || `[0x26000000, 0x2fffffff]` || HighShadow || 91// || `[0x24000000, 0x25ffffff]` || ShadowGap || 92// || `[0x20000000, 0x23ffffff]` || LowShadow || 93// || `[0x00000000, 0x1fffffff]` || LowMem || 94// 95// Default Linux/SystemZ mapping: 96// || `[0x14000000000000, 0x1fffffffffffff]` || HighMem || 97// || `[0x12800000000000, 0x13ffffffffffff]` || HighShadow || 98// || `[0x12000000000000, 0x127fffffffffff]` || ShadowGap || 99// || `[0x10000000000000, 0x11ffffffffffff]` || LowShadow || 100// || `[0x00000000000000, 0x0fffffffffffff]` || LowMem || 101// 102// Shadow mapping on FreeBSD/x86-64 with SHADOW_OFFSET == 0x400000000000: 103// || `[0x500000000000, 0x7fffffffffff]` || HighMem || 104// || `[0x4a0000000000, 0x4fffffffffff]` || HighShadow || 105// || `[0x480000000000, 0x49ffffffffff]` || ShadowGap || 106// || `[0x400000000000, 0x47ffffffffff]` || LowShadow || 107// || `[0x000000000000, 0x3fffffffffff]` || LowMem || 108// 109// Shadow mapping on FreeBSD/i386 with SHADOW_OFFSET == 0x40000000: 110// || `[0x60000000, 0xffffffff]` || HighMem || 111// || `[0x4c000000, 0x5fffffff]` || HighShadow || 112// || `[0x48000000, 0x4bffffff]` || ShadowGap || 113// || `[0x40000000, 0x47ffffff]` || LowShadow || 114// || `[0x00000000, 0x3fffffff]` || LowMem || 115// 116// Shadow mapping on NetBSD/x86-64 with SHADOW_OFFSET == 0x400000000000: 117// || `[0x4feffffffe01, 0x7f7ffffff000]` || HighMem || 118// || `[0x49fdffffffc0, 0x4feffffffe00]` || HighShadow || 119// || `[0x480000000000, 0x49fdffffffbf]` || ShadowGap || 120// || `[0x400000000000, 0x47ffffffffff]` || LowShadow || 121// || `[0x000000000000, 0x3fffffffffff]` || LowMem || 122// 123// Default Windows/i386 mapping: 124// (the exact location of HighShadow/HighMem may vary depending 125// on WoW64, /LARGEADDRESSAWARE, etc). 126// || `[0x50000000, 0xffffffff]` || HighMem || 127// || `[0x3a000000, 0x4fffffff]` || HighShadow || 128// || `[0x36000000, 0x39ffffff]` || ShadowGap || 129// || `[0x30000000, 0x35ffffff]` || LowShadow || 130// || `[0x00000000, 0x2fffffff]` || LowMem || 131 132static const u64 kDefaultShadowScale = 3; 133static const u64 kDefaultShadowSentinel = ~(uptr)0; 134static const u64 kDefaultShadowOffset32 = 1ULL << 29; // 0x20000000 135static const u64 kDefaultShadowOffset64 = 1ULL << 44; 136static const u64 kDefaultShort64bitShadowOffset = 0x7FFF8000; // < 2G. 137static const u64 kIosShadowOffset32 = 1ULL << 30; // 0x40000000 138static const u64 kIosShadowOffset64 = 0x120200000; 139static const u64 kIosSimShadowOffset32 = 1ULL << 30; 140static const u64 kIosSimShadowOffset64 = kDefaultShadowOffset64; 141static const u64 kAArch64_ShadowOffset64 = 1ULL << 36; 142static const u64 kMIPS32_ShadowOffset32 = 0x0aaa0000; 143static const u64 kMIPS64_ShadowOffset64 = 1ULL << 37; 144static const u64 kPPC64_ShadowOffset64 = 1ULL << 41; 145static const u64 kSystemZ_ShadowOffset64 = 1ULL << 52; 146static const u64 kFreeBSD_ShadowOffset32 = 1ULL << 30; // 0x40000000 147static const u64 kFreeBSD_ShadowOffset64 = 1ULL << 46; // 0x400000000000 148static const u64 kNetBSD_ShadowOffset64 = 1ULL << 46; // 0x400000000000 149static const u64 kWindowsShadowOffset32 = 3ULL << 28; // 0x30000000 150 151#define SHADOW_SCALE kDefaultShadowScale 152 153#if SANITIZER_FUCHSIA 154# define SHADOW_OFFSET (0) 155#elif SANITIZER_WORDSIZE == 32 156# if SANITIZER_ANDROID 157# define SHADOW_OFFSET (0) 158# elif defined(__mips__) 159# define SHADOW_OFFSET kMIPS32_ShadowOffset32 160# elif SANITIZER_FREEBSD 161# define SHADOW_OFFSET kFreeBSD_ShadowOffset32 162# elif SANITIZER_WINDOWS 163# define SHADOW_OFFSET kWindowsShadowOffset32 164# elif SANITIZER_IOS 165# if SANITIZER_IOSSIM 166# define SHADOW_OFFSET kIosSimShadowOffset32 167# else 168# define SHADOW_OFFSET kIosShadowOffset32 169# endif 170# else 171# define SHADOW_OFFSET kDefaultShadowOffset32 172# endif 173#else 174# if SANITIZER_IOS 175# if SANITIZER_IOSSIM 176# define SHADOW_OFFSET kIosSimShadowOffset64 177# else 178# define SHADOW_OFFSET __asan_shadow_memory_dynamic_address 179# endif 180# elif defined(__aarch64__) 181# define SHADOW_OFFSET kAArch64_ShadowOffset64 182# elif defined(__powerpc64__) 183# define SHADOW_OFFSET kPPC64_ShadowOffset64 184# elif defined(__s390x__) 185# define SHADOW_OFFSET kSystemZ_ShadowOffset64 186# elif SANITIZER_FREEBSD 187# define SHADOW_OFFSET kFreeBSD_ShadowOffset64 188// XXX: see TARGET_ASAN_SHADOW_OFFSET in gcc. 189// for example ix86_asan_shadow_offset() in i386.c 190// # elif SANITIZER_NETBSD 191// # define SHADOW_OFFSET kNetBSD_ShadowOffset64 192# elif SANITIZER_MAC 193# define SHADOW_OFFSET kDefaultShadowOffset64 194# elif defined(__mips64) 195# define SHADOW_OFFSET kMIPS64_ShadowOffset64 196# elif SANITIZER_WINDOWS64 197# define SHADOW_OFFSET __asan_shadow_memory_dynamic_address 198# else 199# define SHADOW_OFFSET kDefaultShort64bitShadowOffset 200# endif 201#endif 202 203#define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE) 204#define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) + (SHADOW_OFFSET)) 205 206#define kLowMemBeg 0 207#define kLowMemEnd (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0) 208 209#define kLowShadowBeg SHADOW_OFFSET 210#define kLowShadowEnd MEM_TO_SHADOW(kLowMemEnd) 211 212#define kHighMemBeg (MEM_TO_SHADOW(kHighMemEnd) + 1) 213 214#define kHighShadowBeg MEM_TO_SHADOW(kHighMemBeg) 215#define kHighShadowEnd MEM_TO_SHADOW(kHighMemEnd) 216 217# define kMidShadowBeg MEM_TO_SHADOW(kMidMemBeg) 218# define kMidShadowEnd MEM_TO_SHADOW(kMidMemEnd) 219 220// With the zero shadow base we can not actually map pages starting from 0. 221// This constant is somewhat arbitrary. 222#define kZeroBaseShadowStart 0 223#define kZeroBaseMaxShadowStart (1 << 18) 224 225#define kShadowGapBeg (kLowShadowEnd ? kLowShadowEnd + 1 \ 226 : kZeroBaseShadowStart) 227#define kShadowGapEnd ((kMidMemBeg ? kMidShadowBeg : kHighShadowBeg) - 1) 228 229#define kShadowGap2Beg (kMidMemBeg ? kMidShadowEnd + 1 : 0) 230#define kShadowGap2End (kMidMemBeg ? kMidMemBeg - 1 : 0) 231 232#define kShadowGap3Beg (kMidMemBeg ? kMidMemEnd + 1 : 0) 233#define kShadowGap3End (kMidMemBeg ? kHighShadowBeg - 1 : 0) 234 235#define DO_ASAN_MAPPING_PROFILE 0 // Set to 1 to profile the functions below. 236 237#if DO_ASAN_MAPPING_PROFILE 238# define PROFILE_ASAN_MAPPING() AsanMappingProfile[__LINE__]++; 239#else 240# define PROFILE_ASAN_MAPPING() 241#endif 242 243// If 1, all shadow boundaries are constants. 244// Don't set to 1 other than for testing. 245#define ASAN_FIXED_MAPPING 0 246 247namespace __asan { 248 249extern uptr AsanMappingProfile[]; 250 251#if ASAN_FIXED_MAPPING 252// Fixed mapping for 64-bit Linux. Mostly used for performance comparison 253// with non-fixed mapping. As of r175253 (Feb 2013) the performance 254// difference between fixed and non-fixed mapping is below the noise level. 255static uptr kHighMemEnd = 0x7fffffffffffULL; 256static uptr kMidMemBeg = 0x3000000000ULL; 257static uptr kMidMemEnd = 0x4fffffffffULL; 258#else 259extern uptr kHighMemEnd, kMidMemBeg, kMidMemEnd; // Initialized in __asan_init. 260#endif 261 262static inline bool AddrIsInLowMem(uptr a) { 263 PROFILE_ASAN_MAPPING(); 264 return a < kLowMemEnd; 265} 266 267static inline bool AddrIsInLowShadow(uptr a) { 268 PROFILE_ASAN_MAPPING(); 269 return a >= kLowShadowBeg && a <= kLowShadowEnd; 270} 271 272static inline bool AddrIsInHighMem(uptr a) { 273 PROFILE_ASAN_MAPPING(); 274 return a >= kHighMemBeg && a <= kHighMemEnd; 275} 276 277static inline bool AddrIsInMidMem(uptr a) { 278 PROFILE_ASAN_MAPPING(); 279 return kMidMemBeg && a >= kMidMemBeg && a <= kMidMemEnd; 280} 281 282static inline bool AddrIsInShadowGap(uptr a) { 283 PROFILE_ASAN_MAPPING(); 284 if (kMidMemBeg) { 285 if (a <= kShadowGapEnd) 286 return SHADOW_OFFSET == 0 || a >= kShadowGapBeg; 287 return (a >= kShadowGap2Beg && a <= kShadowGap2End) || 288 (a >= kShadowGap3Beg && a <= kShadowGap3End); 289 } 290 // In zero-based shadow mode we treat addresses near zero as addresses 291 // in shadow gap as well. 292 if (SHADOW_OFFSET == 0) 293 return a <= kShadowGapEnd; 294 return a >= kShadowGapBeg && a <= kShadowGapEnd; 295} 296 297static inline bool AddrIsInMem(uptr a) { 298 PROFILE_ASAN_MAPPING(); 299 return AddrIsInLowMem(a) || AddrIsInMidMem(a) || AddrIsInHighMem(a) || 300 (flags()->protect_shadow_gap == 0 && AddrIsInShadowGap(a)); 301} 302 303static inline uptr MemToShadow(uptr p) { 304 PROFILE_ASAN_MAPPING(); 305 CHECK(AddrIsInMem(p)); 306 return MEM_TO_SHADOW(p); 307} 308 309static inline bool AddrIsInHighShadow(uptr a) { 310 PROFILE_ASAN_MAPPING(); 311 return a >= kHighShadowBeg && a <= kHighMemEnd; 312} 313 314static inline bool AddrIsInMidShadow(uptr a) { 315 PROFILE_ASAN_MAPPING(); 316 return kMidMemBeg && a >= kMidShadowBeg && a <= kMidMemEnd; 317} 318 319static inline bool AddrIsInShadow(uptr a) { 320 PROFILE_ASAN_MAPPING(); 321 return AddrIsInLowShadow(a) || AddrIsInMidShadow(a) || AddrIsInHighShadow(a); 322} 323 324static inline bool AddrIsAlignedByGranularity(uptr a) { 325 PROFILE_ASAN_MAPPING(); 326 return (a & (SHADOW_GRANULARITY - 1)) == 0; 327} 328 329static inline bool AddressIsPoisoned(uptr a) { 330 PROFILE_ASAN_MAPPING(); 331 const uptr kAccessSize = 1; 332 u8 *shadow_address = (u8*)MEM_TO_SHADOW(a); 333 s8 shadow_value = *shadow_address; 334 if (shadow_value) { 335 u8 last_accessed_byte = (a & (SHADOW_GRANULARITY - 1)) 336 + kAccessSize - 1; 337 return (last_accessed_byte >= shadow_value); 338 } 339 return false; 340} 341 342// Must be after all calls to PROFILE_ASAN_MAPPING(). 343static const uptr kAsanMappingProfileSize = __LINE__; 344 345} // namespace __asan 346 347#endif // ASAN_MAPPING_H 348