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 19 namespace __asan { 20 21 // Poisons the shadow memory for "size" bytes starting from "addr". 22 void PoisonShadow(uptr addr, uptr size, u8 value); 23 24 // Poisons the shadow memory for "redzone_size" bytes starting from 25 // "addr + size". 26 void 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. 34 ALWAYS_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 43 ALWAYS_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 // first size-i bytes are addressable 54 *shadow = static_cast<u8>(size - i); 55 } 56 } 57 } 58 59 } // namespace __asan 60
