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      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 // https://github.com/google/sanitizers/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 // Default Linux/AArch64 (39-bit VMA) mapping:
     77 // || `[0x2000000000, 0x7fffffffff]` || highmem    ||
     78 // || `[0x1400000000, 0x1fffffffff]` || highshadow ||
     79 // || `[0x1200000000, 0x13ffffffff]` || shadowgap  ||
     80 // || `[0x1000000000, 0x11ffffffff]` || lowshadow  ||
     81 // || `[0x0000000000, 0x0fffffffff]` || lowmem     ||
     82 //
     83 // Default Linux/AArch64 (42-bit VMA) mapping:
     84 // || `[0x10000000000, 0x3ffffffffff]` || highmem    ||
     85 // || `[0x0a000000000, 0x0ffffffffff]` || highshadow ||
     86 // || `[0x09000000000, 0x09fffffffff]` || shadowgap  ||
     87 // || `[0x08000000000, 0x08fffffffff]` || lowshadow  ||
     88 // || `[0x00000000000, 0x07fffffffff]` || lowmem     ||
     89 //
     90 // Default Linux/S390 mapping:
     91 // || `[0x30000000, 0x7fffffff]` || HighMem    ||
     92 // || `[0x26000000, 0x2fffffff]` || HighShadow ||
     93 // || `[0x24000000, 0x25ffffff]` || ShadowGap  ||
     94 // || `[0x20000000, 0x23ffffff]` || LowShadow  ||
     95 // || `[0x00000000, 0x1fffffff]` || LowMem     ||
     96 //
     97 // Default Linux/SystemZ mapping:
     98 // || `[0x14000000000000, 0x1fffffffffffff]` || HighMem    ||
     99 // || `[0x12800000000000, 0x13ffffffffffff]` || HighShadow ||
    100 // || `[0x12000000000000, 0x127fffffffffff]` || ShadowGap  ||
    101 // || `[0x10000000000000, 0x11ffffffffffff]` || LowShadow  ||
    102 // || `[0x00000000000000, 0x0fffffffffffff]` || LowMem     ||
    103 //
    104 // Shadow mapping on FreeBSD/x86-64 with SHADOW_OFFSET == 0x400000000000:
    105 // || `[0x500000000000, 0x7fffffffffff]` || HighMem    ||
    106 // || `[0x4a0000000000, 0x4fffffffffff]` || HighShadow ||
    107 // || `[0x480000000000, 0x49ffffffffff]` || ShadowGap  ||
    108 // || `[0x400000000000, 0x47ffffffffff]` || LowShadow  ||
    109 // || `[0x000000000000, 0x3fffffffffff]` || LowMem     ||
    110 //
    111 // Shadow mapping on FreeBSD/i386 with SHADOW_OFFSET == 0x40000000:
    112 // || `[0x60000000, 0xffffffff]` || HighMem    ||
    113 // || `[0x4c000000, 0x5fffffff]` || HighShadow ||
    114 // || `[0x48000000, 0x4bffffff]` || ShadowGap  ||
    115 // || `[0x40000000, 0x47ffffff]` || LowShadow  ||
    116 // || `[0x00000000, 0x3fffffff]` || LowMem     ||
    117 //
    118 // Default Windows/i386 mapping:
    119 // (the exact location of HighShadow/HighMem may vary depending
    120 //  on WoW64, /LARGEADDRESSAWARE, etc).
    121 // || `[0x50000000, 0xffffffff]` || HighMem    ||
    122 // || `[0x3a000000, 0x4fffffff]` || HighShadow ||
    123 // || `[0x36000000, 0x39ffffff]` || ShadowGap  ||
    124 // || `[0x30000000, 0x35ffffff]` || LowShadow  ||
    125 // || `[0x00000000, 0x2fffffff]` || LowMem     ||
    126 
    127 static const u64 kDefaultShadowScale = 3;
    128 static const u64 kDefaultShadowOffset32 = 1ULL << 29;  // 0x20000000
    129 static const u64 kDefaultShadowOffset64 = 1ULL << 44;
    130 static const u64 kDefaultShort64bitShadowOffset = 0x7FFF8000;  // < 2G.
    131 static const u64 kIosShadowOffset32 = 1ULL << 30;  // 0x40000000
    132 static const u64 kIosShadowOffset64 = 0x120200000;
    133 static const u64 kIosSimShadowOffset32 = 1ULL << 30;
    134 static const u64 kIosSimShadowOffset64 = kDefaultShadowOffset64;
    135 static const u64 kAArch64_ShadowOffset64 = 1ULL << 36;
    136 static const u64 kMIPS32_ShadowOffset32 = 0x0aaa0000;
    137 static const u64 kMIPS64_ShadowOffset64 = 1ULL << 37;
    138 static const u64 kPPC64_ShadowOffset64 = 1ULL << 41;
    139 static const u64 kSystemZ_ShadowOffset64 = 1ULL << 52;
    140 static const u64 kFreeBSD_ShadowOffset32 = 1ULL << 30;  // 0x40000000
    141 static const u64 kFreeBSD_ShadowOffset64 = 1ULL << 46;  // 0x400000000000
    142 static const u64 kWindowsShadowOffset32 = 3ULL << 28;  // 0x30000000
    143 static const u64 kWindowsShadowOffset64 = 1ULL << 45;  // 32TB
    144 
    145 #define SHADOW_SCALE kDefaultShadowScale
    146 
    147 
    148 #if SANITIZER_WORDSIZE == 32
    149 #  if SANITIZER_ANDROID
    150 #    define SHADOW_OFFSET (0)
    151 #  elif defined(__mips__)
    152 #    define SHADOW_OFFSET kMIPS32_ShadowOffset32
    153 #  elif SANITIZER_FREEBSD
    154 #    define SHADOW_OFFSET kFreeBSD_ShadowOffset32
    155 #  elif SANITIZER_WINDOWS
    156 #    define SHADOW_OFFSET kWindowsShadowOffset32
    157 #  elif SANITIZER_IOS
    158 #    if SANITIZER_IOSSIM
    159 #      define SHADOW_OFFSET kIosSimShadowOffset32
    160 #    else
    161 #      define SHADOW_OFFSET kIosShadowOffset32
    162 #    endif
    163 #  else
    164 #    define SHADOW_OFFSET kDefaultShadowOffset32
    165 #  endif
    166 #else
    167 #  if SANITIZER_IOS
    168 #    if SANITIZER_IOSSIM
    169 #      define SHADOW_OFFSET kIosSimShadowOffset64
    170 #    else
    171 #      define SHADOW_OFFSET kIosShadowOffset64
    172 #    endif
    173 #  elif defined(__aarch64__)
    174 #    define SHADOW_OFFSET kAArch64_ShadowOffset64
    175 #  elif defined(__powerpc64__)
    176 #    define SHADOW_OFFSET kPPC64_ShadowOffset64
    177 #  elif defined(__s390x__)
    178 #    define SHADOW_OFFSET kSystemZ_ShadowOffset64
    179 #  elif SANITIZER_FREEBSD
    180 #    define SHADOW_OFFSET kFreeBSD_ShadowOffset64
    181 #  elif SANITIZER_MAC
    182 #   define SHADOW_OFFSET kDefaultShadowOffset64
    183 #  elif defined(__mips64)
    184 #   define SHADOW_OFFSET kMIPS64_ShadowOffset64
    185 #  elif SANITIZER_WINDOWS64
    186 #   define SHADOW_OFFSET kWindowsShadowOffset64
    187 #  else
    188 #   define SHADOW_OFFSET kDefaultShort64bitShadowOffset
    189 #  endif
    190 #endif
    191 
    192 #define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE)
    193 #define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) + (SHADOW_OFFSET))
    194 #define SHADOW_TO_MEM(shadow) (((shadow) - SHADOW_OFFSET) << SHADOW_SCALE)
    195 
    196 #define kLowMemBeg      0
    197 #define kLowMemEnd      (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0)
    198 
    199 #define kLowShadowBeg   SHADOW_OFFSET
    200 #define kLowShadowEnd   MEM_TO_SHADOW(kLowMemEnd)
    201 
    202 #define kHighMemBeg     (MEM_TO_SHADOW(kHighMemEnd) + 1)
    203 
    204 #define kHighShadowBeg  MEM_TO_SHADOW(kHighMemBeg)
    205 #define kHighShadowEnd  MEM_TO_SHADOW(kHighMemEnd)
    206 
    207 # define kMidShadowBeg MEM_TO_SHADOW(kMidMemBeg)
    208 # define kMidShadowEnd MEM_TO_SHADOW(kMidMemEnd)
    209 
    210 // With the zero shadow base we can not actually map pages starting from 0.
    211 // This constant is somewhat arbitrary.
    212 #define kZeroBaseShadowStart 0
    213 #define kZeroBaseMaxShadowStart (1 << 18)
    214 
    215 #define kShadowGapBeg   (kLowShadowEnd ? kLowShadowEnd + 1 \
    216                                        : kZeroBaseShadowStart)
    217 #define kShadowGapEnd   ((kMidMemBeg ? kMidShadowBeg : kHighShadowBeg) - 1)
    218 
    219 #define kShadowGap2Beg (kMidMemBeg ? kMidShadowEnd + 1 : 0)
    220 #define kShadowGap2End (kMidMemBeg ? kMidMemBeg - 1 : 0)
    221 
    222 #define kShadowGap3Beg (kMidMemBeg ? kMidMemEnd + 1 : 0)
    223 #define kShadowGap3End (kMidMemBeg ? kHighShadowBeg - 1 : 0)
    224 
    225 #define DO_ASAN_MAPPING_PROFILE 0  // Set to 1 to profile the functions below.
    226 
    227 #if DO_ASAN_MAPPING_PROFILE
    228 # define PROFILE_ASAN_MAPPING() AsanMappingProfile[__LINE__]++;
    229 #else
    230 # define PROFILE_ASAN_MAPPING()
    231 #endif
    232 
    233 // If 1, all shadow boundaries are constants.
    234 // Don't set to 1 other than for testing.
    235 #define ASAN_FIXED_MAPPING 0
    236 
    237 namespace __asan {
    238 
    239 extern uptr AsanMappingProfile[];
    240 
    241 #if ASAN_FIXED_MAPPING
    242 // Fixed mapping for 64-bit Linux. Mostly used for performance comparison
    243 // with non-fixed mapping. As of r175253 (Feb 2013) the performance
    244 // difference between fixed and non-fixed mapping is below the noise level.
    245 static uptr kHighMemEnd = 0x7fffffffffffULL;
    246 static uptr kMidMemBeg =    0x3000000000ULL;
    247 static uptr kMidMemEnd =    0x4fffffffffULL;
    248 #else
    249 extern uptr kHighMemEnd, kMidMemBeg, kMidMemEnd;  // Initialized in __asan_init.
    250 #endif
    251 
    252 static inline bool AddrIsInLowMem(uptr a) {
    253   PROFILE_ASAN_MAPPING();
    254   return a < kLowMemEnd;
    255 }
    256 
    257 static inline bool AddrIsInLowShadow(uptr a) {
    258   PROFILE_ASAN_MAPPING();
    259   return a >= kLowShadowBeg && a <= kLowShadowEnd;
    260 }
    261 
    262 static inline bool AddrIsInHighMem(uptr a) {
    263   PROFILE_ASAN_MAPPING();
    264   return a >= kHighMemBeg && a <= kHighMemEnd;
    265 }
    266 
    267 static inline bool AddrIsInMidMem(uptr a) {
    268   PROFILE_ASAN_MAPPING();
    269   return kMidMemBeg && a >= kMidMemBeg && a <= kMidMemEnd;
    270 }
    271 
    272 static inline bool AddrIsInMem(uptr a) {
    273   PROFILE_ASAN_MAPPING();
    274   return AddrIsInLowMem(a) || AddrIsInMidMem(a) || AddrIsInHighMem(a);
    275 }
    276 
    277 static inline uptr MemToShadow(uptr p) {
    278   PROFILE_ASAN_MAPPING();
    279   CHECK(AddrIsInMem(p));
    280   return MEM_TO_SHADOW(p);
    281 }
    282 
    283 static inline bool AddrIsInHighShadow(uptr a) {
    284   PROFILE_ASAN_MAPPING();
    285   return a >= kHighShadowBeg && a <= kHighMemEnd;
    286 }
    287 
    288 static inline bool AddrIsInMidShadow(uptr a) {
    289   PROFILE_ASAN_MAPPING();
    290   return kMidMemBeg && a >= kMidShadowBeg && a <= kMidMemEnd;
    291 }
    292 
    293 static inline bool AddrIsInShadow(uptr a) {
    294   PROFILE_ASAN_MAPPING();
    295   return AddrIsInLowShadow(a) || AddrIsInMidShadow(a) || AddrIsInHighShadow(a);
    296 }
    297 
    298 static inline bool AddrIsInShadowGap(uptr a) {
    299   PROFILE_ASAN_MAPPING();
    300   if (kMidMemBeg) {
    301     if (a <= kShadowGapEnd)
    302       return SHADOW_OFFSET == 0 || a >= kShadowGapBeg;
    303     return (a >= kShadowGap2Beg && a <= kShadowGap2End) ||
    304            (a >= kShadowGap3Beg && a <= kShadowGap3End);
    305   }
    306   // In zero-based shadow mode we treat addresses near zero as addresses
    307   // in shadow gap as well.
    308   if (SHADOW_OFFSET == 0)
    309     return a <= kShadowGapEnd;
    310   return a >= kShadowGapBeg && a <= kShadowGapEnd;
    311 }
    312 
    313 static inline bool AddrIsAlignedByGranularity(uptr a) {
    314   PROFILE_ASAN_MAPPING();
    315   return (a & (SHADOW_GRANULARITY - 1)) == 0;
    316 }
    317 
    318 static inline bool AddressIsPoisoned(uptr a) {
    319   PROFILE_ASAN_MAPPING();
    320   const uptr kAccessSize = 1;
    321   u8 *shadow_address = (u8*)MEM_TO_SHADOW(a);
    322   s8 shadow_value = *shadow_address;
    323   if (shadow_value) {
    324     u8 last_accessed_byte = (a & (SHADOW_GRANULARITY - 1))
    325                                  + kAccessSize - 1;
    326     return (last_accessed_byte >= shadow_value);
    327   }
    328   return false;
    329 }
    330 
    331 // Must be after all calls to PROFILE_ASAN_MAPPING().
    332 static const uptr kAsanMappingProfileSize = __LINE__;
    333 
    334 }  // namespace __asan
    335 
    336 #endif  // ASAN_MAPPING_H
    337