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 // http://code.google.com/p/address-sanitizer/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 // Shadow mapping on FreeBSD/x86-64 with SHADOW_OFFSET == 0x400000000000:
89 // || `[0x500000000000, 0x7fffffffffff]` || HighMem ||
90 // || `[0x4a0000000000, 0x4fffffffffff]` || HighShadow ||
91 // || `[0x480000000000, 0x49ffffffffff]` || ShadowGap ||
92 // || `[0x400000000000, 0x47ffffffffff]` || LowShadow ||
93 // || `[0x000000000000, 0x3fffffffffff]` || LowMem ||
94 //
95 // Shadow mapping on FreeBSD/i386 with SHADOW_OFFSET == 0x40000000:
96 // || `[0x60000000, 0xffffffff]` || HighMem ||
97 // || `[0x4c000000, 0x5fffffff]` || HighShadow ||
98 // || `[0x48000000, 0x4bffffff]` || ShadowGap ||
99 // || `[0x40000000, 0x47ffffff]` || LowShadow ||
100 // || `[0x00000000, 0x3fffffff]` || LowMem ||
101 //
102 // Default Windows/i386 mapping:
103 // (the exact location of HighShadow/HighMem may vary depending
104 // on WoW64, /LARGEADDRESSAWARE, etc).
105 // || `[0x50000000, 0xffffffff]` || HighMem ||
106 // || `[0x3a000000, 0x4fffffff]` || HighShadow ||
107 // || `[0x36000000, 0x39ffffff]` || ShadowGap ||
108 // || `[0x30000000, 0x35ffffff]` || LowShadow ||
109 // || `[0x00000000, 0x2fffffff]` || LowMem ||
110
111 static const u64 kDefaultShadowScale = 3;
112 static const u64 kDefaultShadowOffset32 = 1ULL << 29; // 0x20000000
113 static const u64 kDefaultShadowOffset64 = 1ULL << 44;
114 static const u64 kDefaultShort64bitShadowOffset = 0x7FFF8000; // < 2G.
115 static const u64 kIosShadowOffset32 = 1ULL << 30; // 0x40000000
116 static const u64 kIosShadowOffset64 = 0x130000000;
117 static const u64 kIosSimShadowOffset32 = 1ULL << 30;
118 static const u64 kIosSimShadowOffset64 = kDefaultShadowOffset64;
119 static const u64 kAArch64_ShadowOffset64 = 1ULL << 36;
120 static const u64 kMIPS32_ShadowOffset32 = 0x0aaa0000;
121 static const u64 kMIPS64_ShadowOffset64 = 1ULL << 37;
122 static const u64 kPPC64_ShadowOffset64 = 1ULL << 41;
123 static const u64 kFreeBSD_ShadowOffset32 = 1ULL << 30; // 0x40000000
124 static const u64 kFreeBSD_ShadowOffset64 = 1ULL << 46; // 0x400000000000
125 static const u64 kWindowsShadowOffset32 = 3ULL << 28; // 0x30000000
126
127 #define SHADOW_SCALE kDefaultShadowScale
128
129
130 #if SANITIZER_WORDSIZE == 32
131 # if SANITIZER_ANDROID
132 # define SHADOW_OFFSET (0)
133 # elif defined(__mips__)
134 # define SHADOW_OFFSET kMIPS32_ShadowOffset32
135 # elif SANITIZER_FREEBSD
136 # define SHADOW_OFFSET kFreeBSD_ShadowOffset32
137 # elif SANITIZER_WINDOWS
138 # define SHADOW_OFFSET kWindowsShadowOffset32
139 # elif SANITIZER_IOSSIM
140 # define SHADOW_OFFSET kIosSimShadowOffset32
141 # elif SANITIZER_IOS
142 # define SHADOW_OFFSET kIosShadowOffset32
143 # else
144 # define SHADOW_OFFSET kDefaultShadowOffset32
145 # endif
146 #else
147 # if defined(__aarch64__)
148 # define SHADOW_OFFSET kAArch64_ShadowOffset64
149 # elif defined(__powerpc64__)
150 # define SHADOW_OFFSET kPPC64_ShadowOffset64
151 # elif SANITIZER_FREEBSD
152 # define SHADOW_OFFSET kFreeBSD_ShadowOffset64
153 # elif SANITIZER_MAC
154 # define SHADOW_OFFSET kDefaultShadowOffset64
155 # elif defined(__mips64)
156 # define SHADOW_OFFSET kMIPS64_ShadowOffset64
157 # elif SANITIZER_IOSSIM
158 # define SHADOW_OFFSET kIosSimShadowOffset64
159 # elif SANITIZER_IOS
160 # define SHADOW_OFFSET kIosShadowOffset64
161 # else
162 # define SHADOW_OFFSET kDefaultShort64bitShadowOffset
163 # endif
164 #endif
165
166 #define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE)
167 #define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) + (SHADOW_OFFSET))
168 #define SHADOW_TO_MEM(shadow) (((shadow) - SHADOW_OFFSET) << SHADOW_SCALE)
169
170 #define kLowMemBeg 0
171 #define kLowMemEnd (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0)
172
173 #define kLowShadowBeg SHADOW_OFFSET
174 #define kLowShadowEnd MEM_TO_SHADOW(kLowMemEnd)
175
176 #define kHighMemBeg (MEM_TO_SHADOW(kHighMemEnd) + 1)
177
178 #define kHighShadowBeg MEM_TO_SHADOW(kHighMemBeg)
179 #define kHighShadowEnd MEM_TO_SHADOW(kHighMemEnd)
180
181 # define kMidShadowBeg MEM_TO_SHADOW(kMidMemBeg)
182 # define kMidShadowEnd MEM_TO_SHADOW(kMidMemEnd)
183
184 // With the zero shadow base we can not actually map pages starting from 0.
185 // This constant is somewhat arbitrary.
186 #define kZeroBaseShadowStart 0
187 #define kZeroBaseMaxShadowStart (1 << 18)
188
189 #define kShadowGapBeg (kLowShadowEnd ? kLowShadowEnd + 1 \
190 : kZeroBaseShadowStart)
191 #define kShadowGapEnd ((kMidMemBeg ? kMidShadowBeg : kHighShadowBeg) - 1)
192
193 #define kShadowGap2Beg (kMidMemBeg ? kMidShadowEnd + 1 : 0)
194 #define kShadowGap2End (kMidMemBeg ? kMidMemBeg - 1 : 0)
195
196 #define kShadowGap3Beg (kMidMemBeg ? kMidMemEnd + 1 : 0)
197 #define kShadowGap3End (kMidMemBeg ? kHighShadowBeg - 1 : 0)
198
199 #define DO_ASAN_MAPPING_PROFILE 0 // Set to 1 to profile the functions below.
200
201 #if DO_ASAN_MAPPING_PROFILE
202 # define PROFILE_ASAN_MAPPING() AsanMappingProfile[__LINE__]++;
203 #else
204 # define PROFILE_ASAN_MAPPING()
205 #endif
206
207 // If 1, all shadow boundaries are constants.
208 // Don't set to 1 other than for testing.
209 #define ASAN_FIXED_MAPPING 0
210
211 namespace __asan {
212
213 extern uptr AsanMappingProfile[];
214
215 #if ASAN_FIXED_MAPPING
216 // Fixed mapping for 64-bit Linux. Mostly used for performance comparison
217 // with non-fixed mapping. As of r175253 (Feb 2013) the performance
218 // difference between fixed and non-fixed mapping is below the noise level.
219 static uptr kHighMemEnd = 0x7fffffffffffULL;
220 static uptr kMidMemBeg = 0x3000000000ULL;
221 static uptr kMidMemEnd = 0x4fffffffffULL;
222 #else
223 extern uptr kHighMemEnd, kMidMemBeg, kMidMemEnd; // Initialized in __asan_init.
224 #endif
225
AddrIsInLowMem(uptr a)226 static inline bool AddrIsInLowMem(uptr a) {
227 PROFILE_ASAN_MAPPING();
228 return a < kLowMemEnd;
229 }
230
AddrIsInLowShadow(uptr a)231 static inline bool AddrIsInLowShadow(uptr a) {
232 PROFILE_ASAN_MAPPING();
233 return a >= kLowShadowBeg && a <= kLowShadowEnd;
234 }
235
AddrIsInHighMem(uptr a)236 static inline bool AddrIsInHighMem(uptr a) {
237 PROFILE_ASAN_MAPPING();
238 return a >= kHighMemBeg && a <= kHighMemEnd;
239 }
240
AddrIsInMidMem(uptr a)241 static inline bool AddrIsInMidMem(uptr a) {
242 PROFILE_ASAN_MAPPING();
243 return kMidMemBeg && a >= kMidMemBeg && a <= kMidMemEnd;
244 }
245
AddrIsInMem(uptr a)246 static inline bool AddrIsInMem(uptr a) {
247 PROFILE_ASAN_MAPPING();
248 return AddrIsInLowMem(a) || AddrIsInMidMem(a) || AddrIsInHighMem(a);
249 }
250
MemToShadow(uptr p)251 static inline uptr MemToShadow(uptr p) {
252 PROFILE_ASAN_MAPPING();
253 CHECK(AddrIsInMem(p));
254 return MEM_TO_SHADOW(p);
255 }
256
AddrIsInHighShadow(uptr a)257 static inline bool AddrIsInHighShadow(uptr a) {
258 PROFILE_ASAN_MAPPING();
259 return a >= kHighShadowBeg && a <= kHighMemEnd;
260 }
261
AddrIsInMidShadow(uptr a)262 static inline bool AddrIsInMidShadow(uptr a) {
263 PROFILE_ASAN_MAPPING();
264 return kMidMemBeg && a >= kMidShadowBeg && a <= kMidMemEnd;
265 }
266
AddrIsInShadow(uptr a)267 static inline bool AddrIsInShadow(uptr a) {
268 PROFILE_ASAN_MAPPING();
269 return AddrIsInLowShadow(a) || AddrIsInMidShadow(a) || AddrIsInHighShadow(a);
270 }
271
AddrIsInShadowGap(uptr a)272 static inline bool AddrIsInShadowGap(uptr a) {
273 PROFILE_ASAN_MAPPING();
274 if (kMidMemBeg) {
275 if (a <= kShadowGapEnd)
276 return SHADOW_OFFSET == 0 || a >= kShadowGapBeg;
277 return (a >= kShadowGap2Beg && a <= kShadowGap2End) ||
278 (a >= kShadowGap3Beg && a <= kShadowGap3End);
279 }
280 // In zero-based shadow mode we treat addresses near zero as addresses
281 // in shadow gap as well.
282 if (SHADOW_OFFSET == 0)
283 return a <= kShadowGapEnd;
284 return a >= kShadowGapBeg && a <= kShadowGapEnd;
285 }
286
AddrIsAlignedByGranularity(uptr a)287 static inline bool AddrIsAlignedByGranularity(uptr a) {
288 PROFILE_ASAN_MAPPING();
289 return (a & (SHADOW_GRANULARITY - 1)) == 0;
290 }
291
AddressIsPoisoned(uptr a)292 static inline bool AddressIsPoisoned(uptr a) {
293 PROFILE_ASAN_MAPPING();
294 const uptr kAccessSize = 1;
295 u8 *shadow_address = (u8*)MEM_TO_SHADOW(a);
296 s8 shadow_value = *shadow_address;
297 if (shadow_value) {
298 u8 last_accessed_byte = (a & (SHADOW_GRANULARITY - 1))
299 + kAccessSize - 1;
300 return (last_accessed_byte >= shadow_value);
301 }
302 return false;
303 }
304
305 // Must be after all calls to PROFILE_ASAN_MAPPING().
306 static const uptr kAsanMappingProfileSize = __LINE__;
307
308 } // namespace __asan
309
310 #endif // ASAN_MAPPING_H
311