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
132 static const u64 kDefaultShadowScale = 3;
133 static const u64 kDefaultShadowSentinel = ~(uptr)0;
134 static const u64 kDefaultShadowOffset32 = 1ULL << 29; // 0x20000000
135 static const u64 kDefaultShadowOffset64 = 1ULL << 44;
136 static const u64 kDefaultShort64bitShadowOffset = 0x7FFF8000; // < 2G.
137 static const u64 kIosShadowOffset32 = 1ULL << 30; // 0x40000000
138 static const u64 kIosShadowOffset64 = 0x120200000;
139 static const u64 kIosSimShadowOffset32 = 1ULL << 30;
140 static const u64 kIosSimShadowOffset64 = kDefaultShadowOffset64;
141 static const u64 kAArch64_ShadowOffset64 = 1ULL << 36;
142 static const u64 kMIPS32_ShadowOffset32 = 0x0aaa0000;
143 static const u64 kMIPS64_ShadowOffset64 = 1ULL << 37;
144 static const u64 kPPC64_ShadowOffset64 = 1ULL << 41;
145 static const u64 kSystemZ_ShadowOffset64 = 1ULL << 52;
146 static const u64 kFreeBSD_ShadowOffset32 = 1ULL << 30; // 0x40000000
147 static const u64 kFreeBSD_ShadowOffset64 = 1ULL << 46; // 0x400000000000
148 static const u64 kNetBSD_ShadowOffset64 = 1ULL << 46; // 0x400000000000
149 static 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 # elif SANITIZER_NETBSD
189 # define SHADOW_OFFSET kNetBSD_ShadowOffset64
190 # elif SANITIZER_MAC
191 # define SHADOW_OFFSET kDefaultShadowOffset64
192 # elif defined(__mips64)
193 # define SHADOW_OFFSET kMIPS64_ShadowOffset64
194 # elif SANITIZER_WINDOWS64
195 # define SHADOW_OFFSET __asan_shadow_memory_dynamic_address
196 # else
197 # define SHADOW_OFFSET kDefaultShort64bitShadowOffset
198 # endif
199 #endif
200
201 #define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE)
202 #define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) + (SHADOW_OFFSET))
203
204 #define kLowMemBeg 0
205 #define kLowMemEnd (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0)
206
207 #define kLowShadowBeg SHADOW_OFFSET
208 #define kLowShadowEnd MEM_TO_SHADOW(kLowMemEnd)
209
210 #define kHighMemBeg (MEM_TO_SHADOW(kHighMemEnd) + 1)
211
212 #define kHighShadowBeg MEM_TO_SHADOW(kHighMemBeg)
213 #define kHighShadowEnd MEM_TO_SHADOW(kHighMemEnd)
214
215 # define kMidShadowBeg MEM_TO_SHADOW(kMidMemBeg)
216 # define kMidShadowEnd MEM_TO_SHADOW(kMidMemEnd)
217
218 // With the zero shadow base we can not actually map pages starting from 0.
219 // This constant is somewhat arbitrary.
220 #define kZeroBaseShadowStart 0
221 #define kZeroBaseMaxShadowStart (1 << 18)
222
223 #define kShadowGapBeg (kLowShadowEnd ? kLowShadowEnd + 1 \
224 : kZeroBaseShadowStart)
225 #define kShadowGapEnd ((kMidMemBeg ? kMidShadowBeg : kHighShadowBeg) - 1)
226
227 #define kShadowGap2Beg (kMidMemBeg ? kMidShadowEnd + 1 : 0)
228 #define kShadowGap2End (kMidMemBeg ? kMidMemBeg - 1 : 0)
229
230 #define kShadowGap3Beg (kMidMemBeg ? kMidMemEnd + 1 : 0)
231 #define kShadowGap3End (kMidMemBeg ? kHighShadowBeg - 1 : 0)
232
233 #define DO_ASAN_MAPPING_PROFILE 0 // Set to 1 to profile the functions below.
234
235 #if DO_ASAN_MAPPING_PROFILE
236 # define PROFILE_ASAN_MAPPING() AsanMappingProfile[__LINE__]++;
237 #else
238 # define PROFILE_ASAN_MAPPING()
239 #endif
240
241 // If 1, all shadow boundaries are constants.
242 // Don't set to 1 other than for testing.
243 #define ASAN_FIXED_MAPPING 0
244
245 namespace __asan {
246
247 extern uptr AsanMappingProfile[];
248
249 #if ASAN_FIXED_MAPPING
250 // Fixed mapping for 64-bit Linux. Mostly used for performance comparison
251 // with non-fixed mapping. As of r175253 (Feb 2013) the performance
252 // difference between fixed and non-fixed mapping is below the noise level.
253 static uptr kHighMemEnd = 0x7fffffffffffULL;
254 static uptr kMidMemBeg = 0x3000000000ULL;
255 static uptr kMidMemEnd = 0x4fffffffffULL;
256 #else
257 extern uptr kHighMemEnd, kMidMemBeg, kMidMemEnd; // Initialized in __asan_init.
258 #endif
259
AddrIsInLowMem(uptr a)260 static inline bool AddrIsInLowMem(uptr a) {
261 PROFILE_ASAN_MAPPING();
262 return a < kLowMemEnd;
263 }
264
AddrIsInLowShadow(uptr a)265 static inline bool AddrIsInLowShadow(uptr a) {
266 PROFILE_ASAN_MAPPING();
267 return a >= kLowShadowBeg && a <= kLowShadowEnd;
268 }
269
AddrIsInHighMem(uptr a)270 static inline bool AddrIsInHighMem(uptr a) {
271 PROFILE_ASAN_MAPPING();
272 return a >= kHighMemBeg && a <= kHighMemEnd;
273 }
274
AddrIsInMidMem(uptr a)275 static inline bool AddrIsInMidMem(uptr a) {
276 PROFILE_ASAN_MAPPING();
277 return kMidMemBeg && a >= kMidMemBeg && a <= kMidMemEnd;
278 }
279
AddrIsInShadowGap(uptr a)280 static inline bool AddrIsInShadowGap(uptr a) {
281 PROFILE_ASAN_MAPPING();
282 if (kMidMemBeg) {
283 if (a <= kShadowGapEnd)
284 return SHADOW_OFFSET == 0 || a >= kShadowGapBeg;
285 return (a >= kShadowGap2Beg && a <= kShadowGap2End) ||
286 (a >= kShadowGap3Beg && a <= kShadowGap3End);
287 }
288 // In zero-based shadow mode we treat addresses near zero as addresses
289 // in shadow gap as well.
290 if (SHADOW_OFFSET == 0)
291 return a <= kShadowGapEnd;
292 return a >= kShadowGapBeg && a <= kShadowGapEnd;
293 }
294
AddrIsInMem(uptr a)295 static inline bool AddrIsInMem(uptr a) {
296 PROFILE_ASAN_MAPPING();
297 return AddrIsInLowMem(a) || AddrIsInMidMem(a) || AddrIsInHighMem(a) ||
298 (flags()->protect_shadow_gap == 0 && AddrIsInShadowGap(a));
299 }
300
MemToShadow(uptr p)301 static inline uptr MemToShadow(uptr p) {
302 PROFILE_ASAN_MAPPING();
303 CHECK(AddrIsInMem(p));
304 return MEM_TO_SHADOW(p);
305 }
306
AddrIsInHighShadow(uptr a)307 static inline bool AddrIsInHighShadow(uptr a) {
308 PROFILE_ASAN_MAPPING();
309 return a >= kHighShadowBeg && a <= kHighMemEnd;
310 }
311
AddrIsInMidShadow(uptr a)312 static inline bool AddrIsInMidShadow(uptr a) {
313 PROFILE_ASAN_MAPPING();
314 return kMidMemBeg && a >= kMidShadowBeg && a <= kMidMemEnd;
315 }
316
AddrIsInShadow(uptr a)317 static inline bool AddrIsInShadow(uptr a) {
318 PROFILE_ASAN_MAPPING();
319 return AddrIsInLowShadow(a) || AddrIsInMidShadow(a) || AddrIsInHighShadow(a);
320 }
321
AddrIsAlignedByGranularity(uptr a)322 static inline bool AddrIsAlignedByGranularity(uptr a) {
323 PROFILE_ASAN_MAPPING();
324 return (a & (SHADOW_GRANULARITY - 1)) == 0;
325 }
326
AddressIsPoisoned(uptr a)327 static inline bool AddressIsPoisoned(uptr a) {
328 PROFILE_ASAN_MAPPING();
329 const uptr kAccessSize = 1;
330 u8 *shadow_address = (u8*)MEM_TO_SHADOW(a);
331 s8 shadow_value = *shadow_address;
332 if (shadow_value) {
333 u8 last_accessed_byte = (a & (SHADOW_GRANULARITY - 1))
334 + kAccessSize - 1;
335 return (last_accessed_byte >= shadow_value);
336 }
337 return false;
338 }
339
340 // Must be after all calls to PROFILE_ASAN_MAPPING().
341 static const uptr kAsanMappingProfileSize = __LINE__;
342
343 } // namespace __asan
344
345 #endif // ASAN_MAPPING_H
346