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 // http://code.google.com/p/address-sanitizer/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/MIPS mapping:
61 // || `[0x2aaa0000, 0xffffffff]` || HighMem ||
62 // || `[0x0fff4000, 0x2aa9ffff]` || HighShadow ||
63 // || `[0x0bff4000, 0x0fff3fff]` || ShadowGap ||
64 // || `[0x0aaa0000, 0x0bff3fff]` || LowShadow ||
65 // || `[0x00000000, 0x0aa9ffff]` || LowMem ||
67 // Shadow mapping on FreeBSD/x86-64 with SHADOW_OFFSET == 0x400000000000:
68 // || `[0x500000000000, 0x7fffffffffff]` || HighMem ||
69 // || `[0x4a0000000000, 0x4fffffffffff]` || HighShadow ||
70 // || `[0x480000000000, 0x49ffffffffff]` || ShadowGap ||
71 // || `[0x400000000000, 0x47ffffffffff]` || LowShadow ||
72 // || `[0x000000000000, 0x3fffffffffff]` || LowMem ||
74 // Shadow mapping on FreeBSD/i386 with SHADOW_OFFSET == 0x40000000:
75 // || `[0x60000000, 0xffffffff]` || HighMem ||
76 // || `[0x4c000000, 0x5fffffff]` || HighShadow ||
77 // || `[0x48000000, 0x4bffffff]` || ShadowGap ||
78 // || `[0x40000000, 0x47ffffff]` || LowShadow ||
79 // || `[0x00000000, 0x3fffffff]` || LowMem ||
81 static const u64 kDefaultShadowScale
= 3;
82 static const u64 kDefaultShadowOffset32
= 1ULL << 29; // 0x20000000
83 static const u64 kIosShadowOffset32
= 1ULL << 30; // 0x40000000
84 static const u64 kDefaultShadowOffset64
= 1ULL << 44;
85 static const u64 kDefaultShort64bitShadowOffset
= 0x7FFF8000; // < 2G.
86 static const u64 kAArch64_ShadowOffset64
= 1ULL << 36;
87 static const u64 kMIPS32_ShadowOffset32
= 0x0aaa0000;
88 static const u64 kMIPS64_ShadowOffset64
= 1ULL << 36;
89 static const u64 kPPC64_ShadowOffset64
= 1ULL << 41;
90 static const u64 kFreeBSD_ShadowOffset32
= 1ULL << 30; // 0x40000000
91 static const u64 kFreeBSD_ShadowOffset64
= 1ULL << 46; // 0x400000000000
93 #define SHADOW_SCALE kDefaultShadowScale
95 # define SHADOW_OFFSET (0)
97 # if SANITIZER_WORDSIZE == 32
98 # if defined(__mips__)
99 # define SHADOW_OFFSET kMIPS32_ShadowOffset32
100 # elif SANITIZER_FREEBSD
101 # define SHADOW_OFFSET kFreeBSD_ShadowOffset32
104 # define SHADOW_OFFSET kIosShadowOffset32
106 # define SHADOW_OFFSET kDefaultShadowOffset32
110 # if defined(__aarch64__)
111 # define SHADOW_OFFSET kAArch64_ShadowOffset64
112 # elif defined(__powerpc64__)
113 # define SHADOW_OFFSET kPPC64_ShadowOffset64
114 # elif SANITIZER_FREEBSD
115 # define SHADOW_OFFSET kFreeBSD_ShadowOffset64
117 # define SHADOW_OFFSET kDefaultShadowOffset64
118 # elif defined(__mips64)
119 # define SHADOW_OFFSET kMIPS64_ShadowOffset64
121 # define SHADOW_OFFSET kDefaultShort64bitShadowOffset
126 #define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE)
127 #define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) + (SHADOW_OFFSET))
128 #define SHADOW_TO_MEM(shadow) (((shadow) - SHADOW_OFFSET) << SHADOW_SCALE)
131 #define kLowMemEnd (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0)
133 #define kLowShadowBeg SHADOW_OFFSET
134 #define kLowShadowEnd MEM_TO_SHADOW(kLowMemEnd)
136 #define kHighMemBeg (MEM_TO_SHADOW(kHighMemEnd) + 1)
138 #define kHighShadowBeg MEM_TO_SHADOW(kHighMemBeg)
139 #define kHighShadowEnd MEM_TO_SHADOW(kHighMemEnd)
141 # define kMidShadowBeg MEM_TO_SHADOW(kMidMemBeg)
142 # define kMidShadowEnd MEM_TO_SHADOW(kMidMemEnd)
144 // With the zero shadow base we can not actually map pages starting from 0.
145 // This constant is somewhat arbitrary.
146 #define kZeroBaseShadowStart (1 << 18)
148 #define kShadowGapBeg (kLowShadowEnd ? kLowShadowEnd + 1 \
149 : kZeroBaseShadowStart)
150 #define kShadowGapEnd ((kMidMemBeg ? kMidShadowBeg : kHighShadowBeg) - 1)
152 #define kShadowGap2Beg (kMidMemBeg ? kMidShadowEnd + 1 : 0)
153 #define kShadowGap2End (kMidMemBeg ? kMidMemBeg - 1 : 0)
155 #define kShadowGap3Beg (kMidMemBeg ? kMidMemEnd + 1 : 0)
156 #define kShadowGap3End (kMidMemBeg ? kHighShadowBeg - 1 : 0)
158 #define DO_ASAN_MAPPING_PROFILE 0 // Set to 1 to profile the functions below.
160 #if DO_ASAN_MAPPING_PROFILE
161 # define PROFILE_ASAN_MAPPING() AsanMappingProfile[__LINE__]++;
163 # define PROFILE_ASAN_MAPPING()
166 // If 1, all shadow boundaries are constants.
167 // Don't set to 1 other than for testing.
168 #define ASAN_FIXED_MAPPING 0
172 extern uptr AsanMappingProfile
[];
174 #if ASAN_FIXED_MAPPING
175 // Fixed mapping for 64-bit Linux. Mostly used for performance comparison
176 // with non-fixed mapping. As of r175253 (Feb 2013) the performance
177 // difference between fixed and non-fixed mapping is below the noise level.
178 static uptr kHighMemEnd
= 0x7fffffffffffULL
;
179 static uptr kMidMemBeg
= 0x3000000000ULL
;
180 static uptr kMidMemEnd
= 0x4fffffffffULL
;
182 extern uptr kHighMemEnd
, kMidMemBeg
, kMidMemEnd
; // Initialized in __asan_init.
185 static inline bool AddrIsInLowMem(uptr a
) {
186 PROFILE_ASAN_MAPPING();
187 return a
< kLowMemEnd
;
190 static inline bool AddrIsInLowShadow(uptr a
) {
191 PROFILE_ASAN_MAPPING();
192 return a
>= kLowShadowBeg
&& a
<= kLowShadowEnd
;
195 static inline bool AddrIsInHighMem(uptr a
) {
196 PROFILE_ASAN_MAPPING();
197 return a
>= kHighMemBeg
&& a
<= kHighMemEnd
;
200 static inline bool AddrIsInMidMem(uptr a
) {
201 PROFILE_ASAN_MAPPING();
202 return kMidMemBeg
&& a
>= kMidMemBeg
&& a
<= kMidMemEnd
;
205 static inline bool AddrIsInMem(uptr a
) {
206 PROFILE_ASAN_MAPPING();
207 return AddrIsInLowMem(a
) || AddrIsInMidMem(a
) || AddrIsInHighMem(a
);
210 static inline uptr
MemToShadow(uptr p
) {
211 PROFILE_ASAN_MAPPING();
212 CHECK(AddrIsInMem(p
));
213 return MEM_TO_SHADOW(p
);
216 static inline bool AddrIsInHighShadow(uptr a
) {
217 PROFILE_ASAN_MAPPING();
218 return a
>= kHighShadowBeg
&& a
<= kHighMemEnd
;
221 static inline bool AddrIsInMidShadow(uptr a
) {
222 PROFILE_ASAN_MAPPING();
223 return kMidMemBeg
&& a
>= kMidShadowBeg
&& a
<= kMidMemEnd
;
226 static inline bool AddrIsInShadow(uptr a
) {
227 PROFILE_ASAN_MAPPING();
228 return AddrIsInLowShadow(a
) || AddrIsInMidShadow(a
) || AddrIsInHighShadow(a
);
231 static inline bool AddrIsInShadowGap(uptr a
) {
232 PROFILE_ASAN_MAPPING();
234 if (a
<= kShadowGapEnd
)
235 return SHADOW_OFFSET
== 0 || a
>= kShadowGapBeg
;
236 return (a
>= kShadowGap2Beg
&& a
<= kShadowGap2End
) ||
237 (a
>= kShadowGap3Beg
&& a
<= kShadowGap3End
);
239 // In zero-based shadow mode we treat addresses near zero as addresses
240 // in shadow gap as well.
241 if (SHADOW_OFFSET
== 0)
242 return a
<= kShadowGapEnd
;
243 return a
>= kShadowGapBeg
&& a
<= kShadowGapEnd
;
246 static inline bool AddrIsAlignedByGranularity(uptr a
) {
247 PROFILE_ASAN_MAPPING();
248 return (a
& (SHADOW_GRANULARITY
- 1)) == 0;
251 static inline bool AddressIsPoisoned(uptr a
) {
252 PROFILE_ASAN_MAPPING();
253 const uptr kAccessSize
= 1;
254 u8
*shadow_address
= (u8
*)MEM_TO_SHADOW(a
);
255 s8 shadow_value
= *shadow_address
;
257 u8 last_accessed_byte
= (a
& (SHADOW_GRANULARITY
- 1))
259 return (last_accessed_byte
>= shadow_value
);
264 // Must be after all calls to PROFILE_ASAN_MAPPING().
265 static const uptr kAsanMappingProfileSize
= __LINE__
;
267 } // namespace __asan
269 #endif // ASAN_MAPPING_H