134 lines
3.8 KiB
C++
134 lines
3.8 KiB
C++
//===-- asan_mapping.h ------------------------------------------*- C++ -*-===//
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file is a part of AddressSanitizer, an address sanity checker.
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//
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// Defines ASan memory mapping.
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//===----------------------------------------------------------------------===//
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#ifndef ASAN_MAPPING_H
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#define ASAN_MAPPING_H
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#include "asan_internal.h"
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// The full explanation of the memory mapping could be found here:
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// http://code.google.com/p/address-sanitizer/wiki/AddressSanitizerAlgorithm
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#if ASAN_FLEXIBLE_MAPPING_AND_OFFSET == 1
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extern __attribute__((visibility("default"))) uptr __asan_mapping_scale;
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extern __attribute__((visibility("default"))) uptr __asan_mapping_offset;
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# define SHADOW_SCALE (__asan_mapping_scale)
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# define SHADOW_OFFSET (__asan_mapping_offset)
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#else
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# if ASAN_ANDROID
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# define SHADOW_SCALE (3)
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# define SHADOW_OFFSET (0)
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# else
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# define SHADOW_SCALE (3)
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# if SANITIZER_WORDSIZE == 32
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# define SHADOW_OFFSET (1 << 29)
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# else
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# if defined(__powerpc64__)
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# define SHADOW_OFFSET (1ULL << 41)
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# else
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# define SHADOW_OFFSET (1ULL << 44)
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# endif
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# endif
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# endif
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#endif // ASAN_FLEXIBLE_MAPPING_AND_OFFSET
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#define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE)
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#define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) | (SHADOW_OFFSET))
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#define SHADOW_TO_MEM(shadow) (((shadow) - SHADOW_OFFSET) << SHADOW_SCALE)
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#if SANITIZER_WORDSIZE == 64
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# if defined(__powerpc64__)
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static const uptr kHighMemEnd = 0x00000fffffffffffUL;
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# else
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static const uptr kHighMemEnd = 0x00007fffffffffffUL;
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# endif
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#else // SANITIZER_WORDSIZE == 32
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static const uptr kHighMemEnd = 0xffffffff;
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#endif // SANITIZER_WORDSIZE
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#define kLowMemBeg 0
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#define kLowMemEnd (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0)
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#define kLowShadowBeg SHADOW_OFFSET
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#define kLowShadowEnd MEM_TO_SHADOW(kLowMemEnd)
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#define kHighMemBeg (MEM_TO_SHADOW(kHighMemEnd) + 1)
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#define kHighShadowBeg MEM_TO_SHADOW(kHighMemBeg)
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#define kHighShadowEnd MEM_TO_SHADOW(kHighMemEnd)
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// With the zero shadow base we can not actually map pages starting from 0.
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// This constant is somewhat arbitrary.
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#define kZeroBaseShadowStart (1 << 18)
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#define kShadowGapBeg (kLowShadowEnd ? kLowShadowEnd + 1 \
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: kZeroBaseShadowStart)
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#define kShadowGapEnd (kHighShadowBeg - 1)
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#define kGlobalAndStackRedzone \
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(SHADOW_GRANULARITY < 32 ? 32 : SHADOW_GRANULARITY)
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namespace __asan {
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static inline bool AddrIsInLowMem(uptr a) {
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return a < kLowMemEnd;
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}
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static inline bool AddrIsInLowShadow(uptr a) {
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return a >= kLowShadowBeg && a <= kLowShadowEnd;
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}
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static inline bool AddrIsInHighMem(uptr a) {
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return a >= kHighMemBeg && a <= kHighMemEnd;
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}
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static inline bool AddrIsInMem(uptr a) {
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return AddrIsInLowMem(a) || AddrIsInHighMem(a);
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}
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static inline uptr MemToShadow(uptr p) {
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CHECK(AddrIsInMem(p));
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return MEM_TO_SHADOW(p);
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}
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static inline bool AddrIsInHighShadow(uptr a) {
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return a >= kHighShadowBeg && a <= kHighMemEnd;
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}
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static inline bool AddrIsInShadow(uptr a) {
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return AddrIsInLowShadow(a) || AddrIsInHighShadow(a);
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}
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static inline bool AddrIsInShadowGap(uptr a) {
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return a >= kShadowGapBeg && a <= kShadowGapEnd;
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}
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static inline bool AddrIsAlignedByGranularity(uptr a) {
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return (a & (SHADOW_GRANULARITY - 1)) == 0;
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}
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static inline bool AddressIsPoisoned(uptr a) {
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const uptr kAccessSize = 1;
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u8 *shadow_address = (u8*)MemToShadow(a);
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s8 shadow_value = *shadow_address;
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if (shadow_value) {
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u8 last_accessed_byte = (a & (SHADOW_GRANULARITY - 1))
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+ kAccessSize - 1;
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return (last_accessed_byte >= shadow_value);
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}
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return false;
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}
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} // namespace __asan
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#endif // ASAN_MAPPING_H
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