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//===-- asan_poisoning.h ----------------------------------------*- C++ -*-===//
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file is a part of AddressSanitizer, an address sanity checker.
//
// Shadow memory poisoning by ASan RTL and by user application.
//===----------------------------------------------------------------------===//
#include "asan_interceptors.h"
#include "asan_internal.h"
#include "asan_mapping.h"
namespace __asan {
// Poisons the shadow memory for "size" bytes starting from "addr".
void PoisonShadow(uptr addr, uptr size, u8 value);
// Poisons the shadow memory for "redzone_size" bytes starting from
// "addr + size".
void PoisonShadowPartialRightRedzone(uptr addr,
uptr size,
uptr redzone_size,
u8 value);
// Fast versions of PoisonShadow and PoisonShadowPartialRightRedzone that
// assume that memory addresses are properly aligned. Use in
// performance-critical code with care.
ALWAYS_INLINE void FastPoisonShadow(uptr aligned_beg, uptr aligned_size,
u8 value) {
DCHECK(flags()->poison_heap);
uptr shadow_beg = MEM_TO_SHADOW(aligned_beg);
uptr shadow_end = MEM_TO_SHADOW(
aligned_beg + aligned_size - SHADOW_GRANULARITY) + 1;
REAL(memset)((void*)shadow_beg, value, shadow_end - shadow_beg);
}
ALWAYS_INLINE void FastPoisonShadowPartialRightRedzone(
uptr aligned_addr, uptr size, uptr redzone_size, u8 value) {
DCHECK(flags()->poison_heap);
bool poison_partial = flags()->poison_partial;
u8 *shadow = (u8*)MEM_TO_SHADOW(aligned_addr);
for (uptr i = 0; i < redzone_size; i += SHADOW_GRANULARITY, shadow++) {
if (i + SHADOW_GRANULARITY <= size) {
*shadow = 0; // fully addressable
} else if (i >= size) {
*shadow = (SHADOW_GRANULARITY == 128) ? 0xff : value; // unaddressable
} else {
// first size-i bytes are addressable
*shadow = poison_partial ? static_cast<u8>(size - i) : 0;
}
}
}
} // namespace __asan
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