asan_poisoning.h revision 7e8434940a1fe7dce531d4c458ccd714da48f609
1//===-- asan_poisoning.h ----------------------------------------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file is a part of AddressSanitizer, an address sanity checker. 11// 12// Shadow memory poisoning by ASan RTL and by user application. 13//===----------------------------------------------------------------------===// 14 15#include "asan_interceptors.h" 16#include "asan_internal.h" 17#include "asan_mapping.h" 18 19namespace __asan { 20 21// Poisons the shadow memory for "size" bytes starting from "addr". 22void PoisonShadow(uptr addr, uptr size, u8 value); 23 24// Poisons the shadow memory for "redzone_size" bytes starting from 25// "addr + size". 26void PoisonShadowPartialRightRedzone(uptr addr, 27 uptr size, 28 uptr redzone_size, 29 u8 value); 30 31// Fast versions of PoisonShadow and PoisonShadowPartialRightRedzone that 32// assume that memory addresses are properly aligned. Use in 33// performance-critical code with care. 34ALWAYS_INLINE INLINE void FastPoisonShadow(uptr aligned_beg, uptr aligned_size, 35 u8 value) { 36 DCHECK(flags()->poison_heap); 37 uptr shadow_beg = MEM_TO_SHADOW(aligned_beg); 38 uptr shadow_end = MEM_TO_SHADOW( 39 aligned_beg + aligned_size - SHADOW_GRANULARITY) + 1; 40 REAL(memset)((void*)shadow_beg, value, shadow_end - shadow_beg); 41} 42 43ALWAYS_INLINE INLINE void FastPoisonShadowPartialRightRedzone( 44 uptr aligned_addr, uptr size, uptr redzone_size, u8 value) { 45 DCHECK(flags()->poison_heap); 46 u8 *shadow = (u8*)MEM_TO_SHADOW(aligned_addr); 47 for (uptr i = 0; i < redzone_size; i += SHADOW_GRANULARITY, shadow++) { 48 if (i + SHADOW_GRANULARITY <= size) { 49 *shadow = 0; // fully addressable 50 } else if (i >= size) { 51 *shadow = (SHADOW_GRANULARITY == 128) ? 0xff : value; // unaddressable 52 } else { 53 *shadow = size - i; // first size-i bytes are addressable 54 } 55 } 56} 57 58} // namespace __asan 59