1 //===-- asan_mapping.h ------------------------------------------*- C++ -*-===//
3 // This file is distributed under the University of Illinois Open Source
4 // License. See LICENSE.TXT for details.
6 //===----------------------------------------------------------------------===//
8 // This file is a part of AddressSanitizer, an address sanity checker.
10 // Defines ASan memory mapping.
11 //===----------------------------------------------------------------------===//
12 #ifndef ASAN_MAPPING_H
13 #define ASAN_MAPPING_H
15 #include "asan_internal.h"
17 // The full explanation of the memory mapping could be found here:
18 // https://github.com/google/sanitizers/wiki/AddressSanitizerAlgorithm
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 ||
27 // When SHADOW_OFFSET is zero (-pie):
28 // || `[0x100000000000, 0x7fffffffffff]` || HighMem ||
29 // || `[0x020000000000, 0x0fffffffffff]` || HighShadow ||
30 // || `[0x000000040000, 0x01ffffffffff]` || ShadowGap ||
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 ||
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 ||
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 ||
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 ||
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 ||
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 ||
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 ||
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 ||
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 ||
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 ||
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 ||
116 // Default Windows/i386 mapping:
117 // (the exact location of HighShadow/HighMem may vary depending
118 // on WoW64, /LARGEADDRESSAWARE, etc).
119 // || `[0x50000000, 0xffffffff]` || HighMem ||
120 // || `[0x3a000000, 0x4fffffff]` || HighShadow ||
121 // || `[0x36000000, 0x39ffffff]` || ShadowGap ||
122 // || `[0x30000000, 0x35ffffff]` || LowShadow ||
123 // || `[0x00000000, 0x2fffffff]` || LowMem ||
125 static const u64 kDefaultShadowScale
= 3;
126 static const u64 kDefaultShadowSentinel
= ~(uptr
)0;
127 static const u64 kDefaultShadowOffset32
= 1ULL << 29; // 0x20000000
128 static const u64 kDefaultShadowOffset64
= 1ULL << 44;
129 static const u64 kDefaultShort64bitShadowOffset
= 0x7FFF8000; // < 2G.
130 static const u64 kIosShadowOffset32
= 1ULL << 30; // 0x40000000
131 static const u64 kIosShadowOffset64
= 0x120200000;
132 static const u64 kIosSimShadowOffset32
= 1ULL << 30;
133 static const u64 kIosSimShadowOffset64
= kDefaultShadowOffset64
;
134 static const u64 kAArch64_ShadowOffset64
= 1ULL << 36;
135 static const u64 kMIPS32_ShadowOffset32
= 0x0aaa0000;
136 static const u64 kMIPS64_ShadowOffset64
= 1ULL << 37;
137 static const u64 kPPC64_ShadowOffset64
= 1ULL << 41;
138 static const u64 kSystemZ_ShadowOffset64
= 1ULL << 52;
139 static const u64 kFreeBSD_ShadowOffset32
= 1ULL << 30; // 0x40000000
140 static const u64 kFreeBSD_ShadowOffset64
= 1ULL << 46; // 0x400000000000
141 static const u64 kWindowsShadowOffset32
= 3ULL << 28; // 0x30000000
143 #define SHADOW_SCALE kDefaultShadowScale
146 #if SANITIZER_WORDSIZE == 32
147 # if SANITIZER_ANDROID
148 # define SHADOW_OFFSET (0)
149 # elif defined(__mips__)
150 # define SHADOW_OFFSET kMIPS32_ShadowOffset32
151 # elif SANITIZER_FREEBSD
152 # define SHADOW_OFFSET kFreeBSD_ShadowOffset32
153 # elif SANITIZER_WINDOWS
154 # define SHADOW_OFFSET kWindowsShadowOffset32
156 # if SANITIZER_IOSSIM
157 # define SHADOW_OFFSET kIosSimShadowOffset32
159 # define SHADOW_OFFSET kIosShadowOffset32
162 # define SHADOW_OFFSET kDefaultShadowOffset32
166 # if SANITIZER_IOSSIM
167 # define SHADOW_OFFSET kIosSimShadowOffset64
169 # define SHADOW_OFFSET __asan_shadow_memory_dynamic_address
171 # elif defined(__aarch64__)
172 # define SHADOW_OFFSET kAArch64_ShadowOffset64
173 # elif defined(__powerpc64__)
174 # define SHADOW_OFFSET kPPC64_ShadowOffset64
175 # elif defined(__s390x__)
176 # define SHADOW_OFFSET kSystemZ_ShadowOffset64
177 # elif SANITIZER_FREEBSD
178 # define SHADOW_OFFSET kFreeBSD_ShadowOffset64
180 # define SHADOW_OFFSET kDefaultShadowOffset64
181 # elif defined(__mips64)
182 # define SHADOW_OFFSET kMIPS64_ShadowOffset64
183 # elif SANITIZER_WINDOWS64
184 # define SHADOW_OFFSET __asan_shadow_memory_dynamic_address
186 # define SHADOW_OFFSET kDefaultShort64bitShadowOffset
190 #define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE)
191 #define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) + (SHADOW_OFFSET))
192 #define SHADOW_TO_MEM(shadow) (((shadow) - SHADOW_OFFSET) << SHADOW_SCALE)
195 #define kLowMemEnd (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0)
197 #define kLowShadowBeg SHADOW_OFFSET
198 #define kLowShadowEnd MEM_TO_SHADOW(kLowMemEnd)
200 #define kHighMemBeg (MEM_TO_SHADOW(kHighMemEnd) + 1)
202 #define kHighShadowBeg MEM_TO_SHADOW(kHighMemBeg)
203 #define kHighShadowEnd MEM_TO_SHADOW(kHighMemEnd)
205 # define kMidShadowBeg MEM_TO_SHADOW(kMidMemBeg)
206 # define kMidShadowEnd MEM_TO_SHADOW(kMidMemEnd)
208 // With the zero shadow base we can not actually map pages starting from 0.
209 // This constant is somewhat arbitrary.
210 #define kZeroBaseShadowStart 0
211 #define kZeroBaseMaxShadowStart (1 << 18)
213 #define kShadowGapBeg (kLowShadowEnd ? kLowShadowEnd + 1 \
214 : kZeroBaseShadowStart)
215 #define kShadowGapEnd ((kMidMemBeg ? kMidShadowBeg : kHighShadowBeg) - 1)
217 #define kShadowGap2Beg (kMidMemBeg ? kMidShadowEnd + 1 : 0)
218 #define kShadowGap2End (kMidMemBeg ? kMidMemBeg - 1 : 0)
220 #define kShadowGap3Beg (kMidMemBeg ? kMidMemEnd + 1 : 0)
221 #define kShadowGap3End (kMidMemBeg ? kHighShadowBeg - 1 : 0)
223 #define DO_ASAN_MAPPING_PROFILE 0 // Set to 1 to profile the functions below.
225 #if DO_ASAN_MAPPING_PROFILE
226 # define PROFILE_ASAN_MAPPING() AsanMappingProfile[__LINE__]++;
228 # define PROFILE_ASAN_MAPPING()
231 // If 1, all shadow boundaries are constants.
232 // Don't set to 1 other than for testing.
233 #define ASAN_FIXED_MAPPING 0
237 extern uptr AsanMappingProfile
[];
239 #if ASAN_FIXED_MAPPING
240 // Fixed mapping for 64-bit Linux. Mostly used for performance comparison
241 // with non-fixed mapping. As of r175253 (Feb 2013) the performance
242 // difference between fixed and non-fixed mapping is below the noise level.
243 static uptr kHighMemEnd
= 0x7fffffffffffULL
;
244 static uptr kMidMemBeg
= 0x3000000000ULL
;
245 static uptr kMidMemEnd
= 0x4fffffffffULL
;
247 extern uptr kHighMemEnd
, kMidMemBeg
, kMidMemEnd
; // Initialized in __asan_init.
250 static inline bool AddrIsInLowMem(uptr a
) {
251 PROFILE_ASAN_MAPPING();
252 return a
< kLowMemEnd
;
255 static inline bool AddrIsInLowShadow(uptr a
) {
256 PROFILE_ASAN_MAPPING();
257 return a
>= kLowShadowBeg
&& a
<= kLowShadowEnd
;
260 static inline bool AddrIsInHighMem(uptr a
) {
261 PROFILE_ASAN_MAPPING();
262 return a
>= kHighMemBeg
&& a
<= kHighMemEnd
;
265 static inline bool AddrIsInMidMem(uptr a
) {
266 PROFILE_ASAN_MAPPING();
267 return kMidMemBeg
&& a
>= kMidMemBeg
&& a
<= kMidMemEnd
;
270 static inline bool AddrIsInShadowGap(uptr a
) {
271 PROFILE_ASAN_MAPPING();
273 if (a
<= kShadowGapEnd
)
274 return SHADOW_OFFSET
== 0 || a
>= kShadowGapBeg
;
275 return (a
>= kShadowGap2Beg
&& a
<= kShadowGap2End
) ||
276 (a
>= kShadowGap3Beg
&& a
<= kShadowGap3End
);
278 // In zero-based shadow mode we treat addresses near zero as addresses
279 // in shadow gap as well.
280 if (SHADOW_OFFSET
== 0)
281 return a
<= kShadowGapEnd
;
282 return a
>= kShadowGapBeg
&& a
<= kShadowGapEnd
;
285 static inline bool AddrIsInMem(uptr a
) {
286 PROFILE_ASAN_MAPPING();
287 return AddrIsInLowMem(a
) || AddrIsInMidMem(a
) || AddrIsInHighMem(a
) ||
288 (flags()->protect_shadow_gap
== 0 && AddrIsInShadowGap(a
));
291 static inline uptr
MemToShadow(uptr p
) {
292 PROFILE_ASAN_MAPPING();
293 CHECK(AddrIsInMem(p
));
294 return MEM_TO_SHADOW(p
);
297 static inline bool AddrIsInHighShadow(uptr a
) {
298 PROFILE_ASAN_MAPPING();
299 return a
>= kHighShadowBeg
&& a
<= kHighMemEnd
;
302 static inline bool AddrIsInMidShadow(uptr a
) {
303 PROFILE_ASAN_MAPPING();
304 return kMidMemBeg
&& a
>= kMidShadowBeg
&& a
<= kMidMemEnd
;
307 static inline bool AddrIsInShadow(uptr a
) {
308 PROFILE_ASAN_MAPPING();
309 return AddrIsInLowShadow(a
) || AddrIsInMidShadow(a
) || AddrIsInHighShadow(a
);
312 static inline bool AddrIsAlignedByGranularity(uptr a
) {
313 PROFILE_ASAN_MAPPING();
314 return (a
& (SHADOW_GRANULARITY
- 1)) == 0;
317 static inline bool AddressIsPoisoned(uptr a
) {
318 PROFILE_ASAN_MAPPING();
319 const uptr kAccessSize
= 1;
320 u8
*shadow_address
= (u8
*)MEM_TO_SHADOW(a
);
321 s8 shadow_value
= *shadow_address
;
323 u8 last_accessed_byte
= (a
& (SHADOW_GRANULARITY
- 1))
325 return (last_accessed_byte
>= shadow_value
);
330 // Must be after all calls to PROFILE_ASAN_MAPPING().
331 static const uptr kAsanMappingProfileSize
= __LINE__
;
333 } // namespace __asan
335 #endif // ASAN_MAPPING_H