1//===-- asan_mapping.h ------------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file is a part of AddressSanitizer, an address sanity checker.
10//
11// Defines ASan memory mapping.
12//===----------------------------------------------------------------------===//
13#ifndef ASAN_MAPPING_H
14#define ASAN_MAPPING_H
15
16#include "sanitizer_common/sanitizer_platform.h"
17
18// The full explanation of the memory mapping could be found here:
19// https://github.com/google/sanitizers/wiki/AddressSanitizerAlgorithm
20//
21// Typical shadow mapping on Linux/x86_64 with SHADOW_OFFSET == 0x00007fff8000:
22// || `[0x10007fff8000, 0x7fffffffffff]` || HighMem ||
23// || `[0x02008fff7000, 0x10007fff7fff]` || HighShadow ||
24// || `[0x00008fff7000, 0x02008fff6fff]` || ShadowGap ||
25// || `[0x00007fff8000, 0x00008fff6fff]` || LowShadow ||
26// || `[0x000000000000, 0x00007fff7fff]` || LowMem ||
27//
28// When SHADOW_OFFSET is zero (-pie):
29// || `[0x100000000000, 0x7fffffffffff]` || HighMem ||
30// || `[0x020000000000, 0x0fffffffffff]` || HighShadow ||
31// || `[0x000000040000, 0x01ffffffffff]` || ShadowGap ||
32//
33// Special case when something is already mapped between
34// 0x003000000000 and 0x005000000000 (e.g. when prelink is installed):
35// || `[0x10007fff8000, 0x7fffffffffff]` || HighMem ||
36// || `[0x02008fff7000, 0x10007fff7fff]` || HighShadow ||
37// || `[0x005000000000, 0x02008fff6fff]` || ShadowGap3 ||
38// || `[0x003000000000, 0x004fffffffff]` || MidMem ||
39// || `[0x000a7fff8000, 0x002fffffffff]` || ShadowGap2 ||
40// || `[0x00067fff8000, 0x000a7fff7fff]` || MidShadow ||
41// || `[0x00008fff7000, 0x00067fff7fff]` || ShadowGap ||
42// || `[0x00007fff8000, 0x00008fff6fff]` || LowShadow ||
43// || `[0x000000000000, 0x00007fff7fff]` || LowMem ||
44//
45// Default Linux/i386 mapping on x86_64 machine:
46// || `[0x40000000, 0xffffffff]` || HighMem ||
47// || `[0x28000000, 0x3fffffff]` || HighShadow ||
48// || `[0x24000000, 0x27ffffff]` || ShadowGap ||
49// || `[0x20000000, 0x23ffffff]` || LowShadow ||
50// || `[0x00000000, 0x1fffffff]` || LowMem ||
51//
52// Default Linux/i386 mapping on i386 machine
53// (addresses starting with 0xc0000000 are reserved
54// for kernel and thus not sanitized):
55// || `[0x38000000, 0xbfffffff]` || HighMem ||
56// || `[0x27000000, 0x37ffffff]` || HighShadow ||
57// || `[0x24000000, 0x26ffffff]` || ShadowGap ||
58// || `[0x20000000, 0x23ffffff]` || LowShadow ||
59// || `[0x00000000, 0x1fffffff]` || LowMem ||
60//
61// Default Linux/MIPS32 mapping:
62// || `[0x2aaa0000, 0xffffffff]` || HighMem ||
63// || `[0x0fff4000, 0x2aa9ffff]` || HighShadow ||
64// || `[0x0bff4000, 0x0fff3fff]` || ShadowGap ||
65// || `[0x0aaa0000, 0x0bff3fff]` || LowShadow ||
66// || `[0x00000000, 0x0aa9ffff]` || LowMem ||
67//
68// Default Linux/MIPS64 mapping:
69// || `[0x4000000000, 0xffffffffff]` || HighMem ||
70// || `[0x2800000000, 0x3fffffffff]` || HighShadow ||
71// || `[0x2400000000, 0x27ffffffff]` || ShadowGap ||
72// || `[0x2000000000, 0x23ffffffff]` || LowShadow ||
73// || `[0x0000000000, 0x1fffffffff]` || LowMem ||
74//
75// Default Linux/RISCV64 Sv39 mapping with SHADOW_OFFSET == 0xd55550000;
76// (the exact location of SHADOW_OFFSET may vary depending the dynamic probing
77// by FindDynamicShadowStart).
78//
79// || `[0x1555550000, 0x3fffffffff]` || HighMem ||
80// || `[0x0fffffa000, 0x1555555fff]` || HighShadow ||
81// || `[0x0effffa000, 0x0fffff9fff]` || ShadowGap ||
82// || `[0x0d55550000, 0x0effff9fff]` || LowShadow ||
83// || `[0x0000000000, 0x0d5554ffff]` || LowMem ||
84//
85// Default Linux/AArch64 (39-bit VMA) mapping:
86// || `[0x2000000000, 0x7fffffffff]` || highmem ||
87// || `[0x1400000000, 0x1fffffffff]` || highshadow ||
88// || `[0x1200000000, 0x13ffffffff]` || shadowgap ||
89// || `[0x1000000000, 0x11ffffffff]` || lowshadow ||
90// || `[0x0000000000, 0x0fffffffff]` || lowmem ||
91//
92// Default Linux/AArch64 (42-bit VMA) mapping:
93// || `[0x10000000000, 0x3ffffffffff]` || highmem ||
94// || `[0x0a000000000, 0x0ffffffffff]` || highshadow ||
95// || `[0x09000000000, 0x09fffffffff]` || shadowgap ||
96// || `[0x08000000000, 0x08fffffffff]` || lowshadow ||
97// || `[0x00000000000, 0x07fffffffff]` || lowmem ||
98//
99// Default Linux/S390 mapping:
100// || `[0x30000000, 0x7fffffff]` || HighMem ||
101// || `[0x26000000, 0x2fffffff]` || HighShadow ||
102// || `[0x24000000, 0x25ffffff]` || ShadowGap ||
103// || `[0x20000000, 0x23ffffff]` || LowShadow ||
104// || `[0x00000000, 0x1fffffff]` || LowMem ||
105//
106// Default Linux/SystemZ mapping:
107// || `[0x14000000000000, 0x1fffffffffffff]` || HighMem ||
108// || `[0x12800000000000, 0x13ffffffffffff]` || HighShadow ||
109// || `[0x12000000000000, 0x127fffffffffff]` || ShadowGap ||
110// || `[0x10000000000000, 0x11ffffffffffff]` || LowShadow ||
111// || `[0x00000000000000, 0x0fffffffffffff]` || LowMem ||
112//
113// Default Linux/SPARC64 (52-bit VMA) mapping:
114// || `[0x8000000000000, 0xfffffffffffff]` || HighMem ||
115// || `[0x1080000000000, 0x207ffffffffff]` || HighShadow ||
116// || `[0x0090000000000, 0x107ffffffffff]` || ShadowGap ||
117// || `[0x0080000000000, 0x008ffffffffff]` || LowShadow ||
118// || `[0x0000000000000, 0x007ffffffffff]` || LowMem ||
119//
120// Default Linux/LoongArch64 (47-bit VMA) mapping:
121// || `[0x500000000000, 0x7fffffffffff]` || HighMem ||
122// || `[0x4a0000000000, 0x4fffffffffff]` || HighShadow ||
123// || `[0x480000000000, 0x49ffffffffff]` || ShadowGap ||
124// || `[0x400000000000, 0x47ffffffffff]` || LowShadow ||
125// || `[0x000000000000, 0x3fffffffffff]` || LowMem ||
126//
127// Shadow mapping on FreeBSD/x86-64 with SHADOW_OFFSET == 0x400000000000:
128// || `[0x500000000000, 0x7fffffffffff]` || HighMem ||
129// || `[0x4a0000000000, 0x4fffffffffff]` || HighShadow ||
130// || `[0x480000000000, 0x49ffffffffff]` || ShadowGap ||
131// || `[0x400000000000, 0x47ffffffffff]` || LowShadow ||
132// || `[0x000000000000, 0x3fffffffffff]` || LowMem ||
133//
134// Shadow mapping on FreeBSD/i386 with SHADOW_OFFSET == 0x40000000:
135// || `[0x60000000, 0xffffffff]` || HighMem ||
136// || `[0x4c000000, 0x5fffffff]` || HighShadow ||
137// || `[0x48000000, 0x4bffffff]` || ShadowGap ||
138// || `[0x40000000, 0x47ffffff]` || LowShadow ||
139// || `[0x00000000, 0x3fffffff]` || LowMem ||
140//
141// Shadow mapping on NetBSD/x86-64 with SHADOW_OFFSET == 0x400000000000:
142// || `[0x4feffffffe01, 0x7f7ffffff000]` || HighMem ||
143// || `[0x49fdffffffc0, 0x4feffffffe00]` || HighShadow ||
144// || `[0x480000000000, 0x49fdffffffbf]` || ShadowGap ||
145// || `[0x400000000000, 0x47ffffffffff]` || LowShadow ||
146// || `[0x000000000000, 0x3fffffffffff]` || LowMem ||
147//
148// Shadow mapping on NetBSD/i386 with SHADOW_OFFSET == 0x40000000:
149// || `[0x60000000, 0xfffff000]` || HighMem ||
150// || `[0x4c000000, 0x5fffffff]` || HighShadow ||
151// || `[0x48000000, 0x4bffffff]` || ShadowGap ||
152// || `[0x40000000, 0x47ffffff]` || LowShadow ||
153// || `[0x00000000, 0x3fffffff]` || LowMem ||
154//
155// Default Windows/i386 mapping:
156// (the exact location of HighShadow/HighMem may vary depending
157// on WoW64, /LARGEADDRESSAWARE, etc).
158// || `[0x50000000, 0xffffffff]` || HighMem ||
159// || `[0x3a000000, 0x4fffffff]` || HighShadow ||
160// || `[0x36000000, 0x39ffffff]` || ShadowGap ||
161// || `[0x30000000, 0x35ffffff]` || LowShadow ||
162// || `[0x00000000, 0x2fffffff]` || LowMem ||
163
164#define ASAN_SHADOW_SCALE 3
165
166#if SANITIZER_FUCHSIA
167# define ASAN_SHADOW_OFFSET_CONST (0)
168#elif SANITIZER_WORDSIZE == 32
169# if SANITIZER_ANDROID
170# define ASAN_SHADOW_OFFSET_DYNAMIC
171# elif defined(__mips__)
172# define ASAN_SHADOW_OFFSET_CONST 0x0aaa0000
173# elif SANITIZER_FREEBSD
174# define ASAN_SHADOW_OFFSET_CONST 0x40000000
175# elif SANITIZER_NETBSD
176# define ASAN_SHADOW_OFFSET_CONST 0x40000000
177# elif SANITIZER_WINDOWS
178# define ASAN_SHADOW_OFFSET_CONST 0x30000000
179# elif SANITIZER_IOS
180# define ASAN_SHADOW_OFFSET_DYNAMIC
181# else
182# define ASAN_SHADOW_OFFSET_CONST 0x20000000
183# endif
184#else
185# if SANITIZER_IOS
186# define ASAN_SHADOW_OFFSET_DYNAMIC
187# elif SANITIZER_APPLE && defined(__aarch64__)
188# define ASAN_SHADOW_OFFSET_DYNAMIC
189# elif SANITIZER_FREEBSD && defined(__aarch64__)
190# define ASAN_SHADOW_OFFSET_CONST 0x0000800000000000
191# elif SANITIZER_RISCV64
192# define ASAN_SHADOW_OFFSET_DYNAMIC
193# elif defined(__aarch64__)
194# define ASAN_SHADOW_OFFSET_CONST 0x0000001000000000
195# elif defined(__powerpc64__)
196# define ASAN_SHADOW_OFFSET_CONST 0x0000100000000000
197# elif defined(__s390x__)
198# define ASAN_SHADOW_OFFSET_CONST 0x0010000000000000
199# elif SANITIZER_FREEBSD
200# define ASAN_SHADOW_OFFSET_CONST 0x0000400000000000
201# elif SANITIZER_NETBSD
202# define ASAN_SHADOW_OFFSET_CONST 0x0000400000000000
203# elif SANITIZER_APPLE
204# define ASAN_SHADOW_OFFSET_CONST 0x0000100000000000
205# elif defined(__mips64)
206# define ASAN_SHADOW_OFFSET_CONST 0x0000002000000000
207# elif defined(__sparc__)
208# define ASAN_SHADOW_OFFSET_CONST 0x0000080000000000
209# elif SANITIZER_LOONGARCH64
210# define ASAN_SHADOW_OFFSET_CONST 0x0000400000000000
211# elif SANITIZER_WINDOWS64
212# define ASAN_SHADOW_OFFSET_DYNAMIC
213# else
214# if ASAN_SHADOW_SCALE != 3
215# error "Value below is based on shadow scale = 3."
216# error "Original formula was: 0x7FFFFFFF & (~0xFFFULL << SHADOW_SCALE)."
217# endif
218# define ASAN_SHADOW_OFFSET_CONST 0x000000007fff8000
219# endif
220#endif
221
222#if defined(__cplusplus)
223# include "asan_internal.h"
224
225static const u64 kDefaultShadowSentinel = ~(uptr)0;
226
227# if defined(ASAN_SHADOW_OFFSET_CONST)
228static const u64 kConstShadowOffset = ASAN_SHADOW_OFFSET_CONST;
229# define ASAN_SHADOW_OFFSET kConstShadowOffset
230# elif defined(ASAN_SHADOW_OFFSET_DYNAMIC)
231# define ASAN_SHADOW_OFFSET __asan_shadow_memory_dynamic_address
232# else
233# error "ASAN_SHADOW_OFFSET can't be determined."
234# endif
235
236# if SANITIZER_ANDROID && defined(__arm__)
237# define ASAN_PREMAP_SHADOW 1
238# else
239# define ASAN_PREMAP_SHADOW 0
240# endif
241
242# define ASAN_SHADOW_GRANULARITY (1ULL << ASAN_SHADOW_SCALE)
243
244# define DO_ASAN_MAPPING_PROFILE 0 // Set to 1 to profile the functions below.
245
246# if DO_ASAN_MAPPING_PROFILE
247# define PROFILE_ASAN_MAPPING() AsanMappingProfile[__LINE__]++;
248# else
249# define PROFILE_ASAN_MAPPING()
250# endif
251
252// If 1, all shadow boundaries are constants.
253// Don't set to 1 other than for testing.
254# define ASAN_FIXED_MAPPING 0
255
256namespace __asan {
257
258extern uptr AsanMappingProfile[];
259
260# if ASAN_FIXED_MAPPING
261// Fixed mapping for 64-bit Linux. Mostly used for performance comparison
262// with non-fixed mapping. As of r175253 (Feb 2013) the performance
263// difference between fixed and non-fixed mapping is below the noise level.
264static uptr kHighMemEnd = 0x7fffffffffffULL;
265static uptr kMidMemBeg = 0x3000000000ULL;
266static uptr kMidMemEnd = 0x4fffffffffULL;
267# else
268extern uptr kHighMemEnd, kMidMemBeg, kMidMemEnd; // Initialized in __asan_init.
269# endif
270
271} // namespace __asan
272
273# if defined(__sparc__) && SANITIZER_WORDSIZE == 64
274# include "asan_mapping_sparc64.h"
275# else
276# define MEM_TO_SHADOW(mem) \
277 (((mem) >> ASAN_SHADOW_SCALE) + (ASAN_SHADOW_OFFSET))
278# define SHADOW_TO_MEM(mem) \
279 (((mem) - (ASAN_SHADOW_OFFSET)) << (ASAN_SHADOW_SCALE))
280
281# define kLowMemBeg 0
282# define kLowMemEnd (ASAN_SHADOW_OFFSET ? ASAN_SHADOW_OFFSET - 1 : 0)
283
284# define kLowShadowBeg ASAN_SHADOW_OFFSET
285# define kLowShadowEnd MEM_TO_SHADOW(kLowMemEnd)
286
287# define kHighMemBeg (MEM_TO_SHADOW(kHighMemEnd) + 1)
288
289# define kHighShadowBeg MEM_TO_SHADOW(kHighMemBeg)
290# define kHighShadowEnd MEM_TO_SHADOW(kHighMemEnd)
291
292# define kMidShadowBeg MEM_TO_SHADOW(kMidMemBeg)
293# define kMidShadowEnd MEM_TO_SHADOW(kMidMemEnd)
294
295// With the zero shadow base we can not actually map pages starting from 0.
296// This constant is somewhat arbitrary.
297# define kZeroBaseShadowStart 0
298# define kZeroBaseMaxShadowStart (1 << 18)
299
300# define kShadowGapBeg \
301 (kLowShadowEnd ? kLowShadowEnd + 1 : kZeroBaseShadowStart)
302# define kShadowGapEnd ((kMidMemBeg ? kMidShadowBeg : kHighShadowBeg) - 1)
303
304# define kShadowGap2Beg (kMidMemBeg ? kMidShadowEnd + 1 : 0)
305# define kShadowGap2End (kMidMemBeg ? kMidMemBeg - 1 : 0)
306
307# define kShadowGap3Beg (kMidMemBeg ? kMidMemEnd + 1 : 0)
308# define kShadowGap3End (kMidMemBeg ? kHighShadowBeg - 1 : 0)
309
310namespace __asan {
311
312static inline bool AddrIsInLowMem(uptr a) {
313 PROFILE_ASAN_MAPPING();
314 return a <= kLowMemEnd;
315}
316
317static inline bool AddrIsInLowShadow(uptr a) {
318 PROFILE_ASAN_MAPPING();
319 return a >= kLowShadowBeg && a <= kLowShadowEnd;
320}
321
322static inline bool AddrIsInMidMem(uptr a) {
323 PROFILE_ASAN_MAPPING();
324 return kMidMemBeg && a >= kMidMemBeg && a <= kMidMemEnd;
325}
326
327static inline bool AddrIsInMidShadow(uptr a) {
328 PROFILE_ASAN_MAPPING();
329 return kMidMemBeg && a >= kMidShadowBeg && a <= kMidShadowEnd;
330}
331
332static inline bool AddrIsInHighMem(uptr a) {
333 PROFILE_ASAN_MAPPING();
334 return kHighMemBeg && a >= kHighMemBeg && a <= kHighMemEnd;
335}
336
337static inline bool AddrIsInHighShadow(uptr a) {
338 PROFILE_ASAN_MAPPING();
339 return kHighMemBeg && a >= kHighShadowBeg && a <= kHighShadowEnd;
340}
341
342static inline bool AddrIsInShadowGap(uptr a) {
343 PROFILE_ASAN_MAPPING();
344 if (kMidMemBeg) {
345 if (a <= kShadowGapEnd)
346 return ASAN_SHADOW_OFFSET == 0 || a >= kShadowGapBeg;
347 return (a >= kShadowGap2Beg && a <= kShadowGap2End) ||
348 (a >= kShadowGap3Beg && a <= kShadowGap3End);
349 }
350 // In zero-based shadow mode we treat addresses near zero as addresses
351 // in shadow gap as well.
352 if (ASAN_SHADOW_OFFSET == 0)
353 return a <= kShadowGapEnd;
354 return a >= kShadowGapBeg && a <= kShadowGapEnd;
355}
356
357} // namespace __asan
358
359# endif
360
361namespace __asan {
362
363static inline uptr MemToShadowSize(uptr size) {
364 return size >> ASAN_SHADOW_SCALE;
365}
366
367static inline bool AddrIsInMem(uptr a) {
368 PROFILE_ASAN_MAPPING();
369 return AddrIsInLowMem(a) || AddrIsInMidMem(a) || AddrIsInHighMem(a) ||
370 (flags()->protect_shadow_gap == 0 && AddrIsInShadowGap(a));
371}
372
373static inline uptr MemToShadow(uptr p) {
374 PROFILE_ASAN_MAPPING();
375 CHECK(AddrIsInMem(p));
376 return MEM_TO_SHADOW(p);
377}
378
379static inline bool AddrIsInShadow(uptr a) {
380 PROFILE_ASAN_MAPPING();
381 return AddrIsInLowShadow(a) || AddrIsInMidShadow(a) || AddrIsInHighShadow(a);
382}
383
384static inline uptr ShadowToMem(uptr p) {
385 PROFILE_ASAN_MAPPING();
386 CHECK(AddrIsInShadow(p));
387 return SHADOW_TO_MEM(p);
388}
389
390static inline bool AddrIsAlignedByGranularity(uptr a) {
391 PROFILE_ASAN_MAPPING();
392 return (a & (ASAN_SHADOW_GRANULARITY - 1)) == 0;
393}
394
395static inline bool AddressIsPoisoned(uptr a) {
396 PROFILE_ASAN_MAPPING();
397 const uptr kAccessSize = 1;
398 u8 *shadow_address = (u8 *)MEM_TO_SHADOW(a);
399 s8 shadow_value = *shadow_address;
400 if (shadow_value) {
401 u8 last_accessed_byte =
402 (a & (ASAN_SHADOW_GRANULARITY - 1)) + kAccessSize - 1;
403 return (last_accessed_byte >= shadow_value);
404 }
405 return false;
406}
407
408// Must be after all calls to PROFILE_ASAN_MAPPING().
409static const uptr kAsanMappingProfileSize = __LINE__;
410
411} // namespace __asan
412
413#endif // __cplusplus
414
415#endif // ASAN_MAPPING_H
416