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.
FastPoisonShadow(uptr aligned_beg,uptr aligned_size,u8 value)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
FastPoisonShadowPartialRightRedzone(uptr aligned_addr,uptr size,uptr redzone_size,u8 value)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