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ef1b3fda KS |
1 | //===-- asan_poisoning.h ----------------------------------------*- C++ -*-===// |
2 | // | |
3 | // This file is distributed under the University of Illinois Open Source | |
4 | // License. See LICENSE.TXT for details. | |
5 | // | |
6 | //===----------------------------------------------------------------------===// | |
7 | // | |
8 | // This file is a part of AddressSanitizer, an address sanity checker. | |
9 | // | |
10 | // Shadow memory poisoning by ASan RTL and by user application. | |
11 | //===----------------------------------------------------------------------===// | |
12 | ||
13 | #include "asan_interceptors.h" | |
14 | #include "asan_internal.h" | |
15 | #include "asan_mapping.h" | |
dee5ea7a | 16 | #include "sanitizer_common/sanitizer_flags.h" |
ef1b3fda KS |
17 | |
18 | namespace __asan { | |
19 | ||
696d846a MO |
20 | // Enable/disable memory poisoning. |
21 | void SetCanPoisonMemory(bool value); | |
22 | bool CanPoisonMemory(); | |
23 | ||
ef1b3fda KS |
24 | // Poisons the shadow memory for "size" bytes starting from "addr". |
25 | void PoisonShadow(uptr addr, uptr size, u8 value); | |
26 | ||
27 | // Poisons the shadow memory for "redzone_size" bytes starting from | |
28 | // "addr + size". | |
29 | void PoisonShadowPartialRightRedzone(uptr addr, | |
30 | uptr size, | |
31 | uptr redzone_size, | |
32 | u8 value); | |
33 | ||
34 | // Fast versions of PoisonShadow and PoisonShadowPartialRightRedzone that | |
35 | // assume that memory addresses are properly aligned. Use in | |
36 | // performance-critical code with care. | |
37 | ALWAYS_INLINE void FastPoisonShadow(uptr aligned_beg, uptr aligned_size, | |
38 | u8 value) { | |
696d846a | 39 | DCHECK(CanPoisonMemory()); |
ef1b3fda KS |
40 | uptr shadow_beg = MEM_TO_SHADOW(aligned_beg); |
41 | uptr shadow_end = MEM_TO_SHADOW( | |
42 | aligned_beg + aligned_size - SHADOW_GRANULARITY) + 1; | |
dee5ea7a KS |
43 | // FIXME: Page states are different on Windows, so using the same interface |
44 | // for mapping shadow and zeroing out pages doesn't "just work", so we should | |
45 | // probably provide higher-level interface for these operations. | |
46 | // For now, just memset on Windows. | |
47 | if (value || | |
48 | SANITIZER_WINDOWS == 1 || | |
49 | shadow_end - shadow_beg < common_flags()->clear_shadow_mmap_threshold) { | |
50 | REAL(memset)((void*)shadow_beg, value, shadow_end - shadow_beg); | |
51 | } else { | |
866e32ad KS |
52 | uptr page_size = GetPageSizeCached(); |
53 | uptr page_beg = RoundUpTo(shadow_beg, page_size); | |
54 | uptr page_end = RoundDownTo(shadow_end, page_size); | |
dee5ea7a KS |
55 | |
56 | if (page_beg >= page_end) { | |
57 | REAL(memset)((void *)shadow_beg, 0, shadow_end - shadow_beg); | |
58 | } else { | |
59 | if (page_beg != shadow_beg) { | |
60 | REAL(memset)((void *)shadow_beg, 0, page_beg - shadow_beg); | |
61 | } | |
62 | if (page_end != shadow_end) { | |
63 | REAL(memset)((void *)page_end, 0, shadow_end - page_end); | |
64 | } | |
696d846a | 65 | ReserveShadowMemoryRange(page_beg, page_end - 1, nullptr); |
dee5ea7a KS |
66 | } |
67 | } | |
ef1b3fda KS |
68 | } |
69 | ||
70 | ALWAYS_INLINE void FastPoisonShadowPartialRightRedzone( | |
71 | uptr aligned_addr, uptr size, uptr redzone_size, u8 value) { | |
696d846a | 72 | DCHECK(CanPoisonMemory()); |
df77f0e4 | 73 | bool poison_partial = flags()->poison_partial; |
ef1b3fda KS |
74 | u8 *shadow = (u8*)MEM_TO_SHADOW(aligned_addr); |
75 | for (uptr i = 0; i < redzone_size; i += SHADOW_GRANULARITY, shadow++) { | |
76 | if (i + SHADOW_GRANULARITY <= size) { | |
77 | *shadow = 0; // fully addressable | |
78 | } else if (i >= size) { | |
79 | *shadow = (SHADOW_GRANULARITY == 128) ? 0xff : value; // unaddressable | |
80 | } else { | |
81 | // first size-i bytes are addressable | |
df77f0e4 | 82 | *shadow = poison_partial ? static_cast<u8>(size - i) : 0; |
ef1b3fda KS |
83 | } |
84 | } | |
85 | } | |
86 | ||
10189819 | 87 | // Calls __sanitizer::ReleaseMemoryToOS() on |
dee5ea7a KS |
88 | // [MemToShadow(p), MemToShadow(p+size)] with proper rounding. |
89 | void FlushUnneededASanShadowMemory(uptr p, uptr size); | |
90 | ||
ef1b3fda | 91 | } // namespace __asan |