1 //===-- msan_poisoning.cc ---------------------------------------*- 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 MemorySanitizer. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "msan_poisoning.h" 15 16 #include "interception/interception.h" 17 #include "msan_origin.h" 18 #include "sanitizer_common/sanitizer_common.h" 19 20 DECLARE_REAL(void *, memset, void *dest, int c, uptr n) 21 DECLARE_REAL(void *, memcpy, void *dest, const void *src, uptr n) 22 DECLARE_REAL(void *, memmove, void *dest, const void *src, uptr n) 23 24 namespace __msan { 25 26 u32 GetOriginIfPoisoned(uptr addr, uptr size) { 27 unsigned char *s = (unsigned char *)MEM_TO_SHADOW(addr); 28 for (uptr i = 0; i < size; ++i) 29 if (s[i]) return *(u32 *)SHADOW_TO_ORIGIN(((uptr)s + i) & ~3UL); 30 return 0; 31 } 32 33 void SetOriginIfPoisoned(uptr addr, uptr src_shadow, uptr size, 34 u32 src_origin) { 35 uptr dst_s = MEM_TO_SHADOW(addr); 36 uptr src_s = src_shadow; 37 uptr src_s_end = src_s + size; 38 39 for (; src_s < src_s_end; ++dst_s, ++src_s) 40 if (*(u8 *)src_s) *(u32 *)SHADOW_TO_ORIGIN(dst_s & ~3UL) = src_origin; 41 } 42 43 void CopyOrigin(const void *dst, const void *src, uptr size, 44 StackTrace *stack) { 45 if (!MEM_IS_APP(dst) || !MEM_IS_APP(src)) return; 46 47 uptr d = (uptr)dst; 48 uptr beg = d & ~3UL; 49 // Copy left unaligned origin if that memory is poisoned. 50 if (beg < d) { 51 u32 o = GetOriginIfPoisoned((uptr)src, d - beg); 52 if (o) { 53 if (__msan_get_track_origins() > 1) o = ChainOrigin(o, stack); 54 *(u32 *)MEM_TO_ORIGIN(beg) = o; 55 } 56 beg += 4; 57 } 58 59 uptr end = (d + size) & ~3UL; 60 // If both ends fall into the same 4-byte slot, we are done. 61 if (end < beg) return; 62 63 // Copy right unaligned origin if that memory is poisoned. 64 if (end < d + size) { 65 u32 o = GetOriginIfPoisoned((uptr)src + (end - d), (d + size) - end); 66 if (o) { 67 if (__msan_get_track_origins() > 1) o = ChainOrigin(o, stack); 68 *(u32 *)MEM_TO_ORIGIN(end) = o; 69 } 70 } 71 72 if (beg < end) { 73 // Align src up. 74 uptr s = ((uptr)src + 3) & ~3UL; 75 // FIXME: factor out to msan_copy_origin_aligned 76 if (__msan_get_track_origins() > 1) { 77 u32 *src = (u32 *)MEM_TO_ORIGIN(s); 78 u32 *src_s = (u32 *)MEM_TO_SHADOW(s); 79 u32 *src_end = (u32 *)MEM_TO_ORIGIN(s + (end - beg)); 80 u32 *dst = (u32 *)MEM_TO_ORIGIN(beg); 81 u32 src_o = 0; 82 u32 dst_o = 0; 83 for (; src < src_end; ++src, ++src_s, ++dst) { 84 if (!*src_s) continue; 85 if (*src != src_o) { 86 src_o = *src; 87 dst_o = ChainOrigin(src_o, stack); 88 } 89 *dst = dst_o; 90 } 91 } else { 92 REAL(memcpy)((void *)MEM_TO_ORIGIN(beg), (void *)MEM_TO_ORIGIN(s), 93 end - beg); 94 } 95 } 96 } 97 98 void MoveShadowAndOrigin(const void *dst, const void *src, uptr size, 99 StackTrace *stack) { 100 if (!MEM_IS_APP(dst)) return; 101 if (!MEM_IS_APP(src)) return; 102 if (src == dst) return; 103 REAL(memmove)((void *)MEM_TO_SHADOW((uptr)dst), 104 (void *)MEM_TO_SHADOW((uptr)src), size); 105 if (__msan_get_track_origins()) CopyOrigin(dst, src, size, stack); 106 } 107 108 void CopyShadowAndOrigin(const void *dst, const void *src, uptr size, 109 StackTrace *stack) { 110 if (!MEM_IS_APP(dst)) return; 111 if (!MEM_IS_APP(src)) return; 112 REAL(memcpy)((void *)MEM_TO_SHADOW((uptr)dst), 113 (void *)MEM_TO_SHADOW((uptr)src), size); 114 if (__msan_get_track_origins()) CopyOrigin(dst, src, size, stack); 115 } 116 117 void CopyMemory(void *dst, const void *src, uptr size, StackTrace *stack) { 118 REAL(memcpy)(dst, src, size); 119 CopyShadowAndOrigin(dst, src, size, stack); 120 } 121 122 void SetShadow(const void *ptr, uptr size, u8 value) { 123 uptr PageSize = GetPageSizeCached(); 124 uptr shadow_beg = MEM_TO_SHADOW(ptr); 125 uptr shadow_end = shadow_beg + size; 126 if (value || 127 shadow_end - shadow_beg < common_flags()->clear_shadow_mmap_threshold) { 128 REAL(memset)((void *)shadow_beg, value, shadow_end - shadow_beg); 129 } else { 130 uptr page_beg = RoundUpTo(shadow_beg, PageSize); 131 uptr page_end = RoundDownTo(shadow_end, PageSize); 132 133 if (page_beg >= page_end) { 134 REAL(memset)((void *)shadow_beg, 0, shadow_end - shadow_beg); 135 } else { 136 if (page_beg != shadow_beg) { 137 REAL(memset)((void *)shadow_beg, 0, page_beg - shadow_beg); 138 } 139 if (page_end != shadow_end) { 140 REAL(memset)((void *)page_end, 0, shadow_end - page_end); 141 } 142 MmapFixedNoReserve(page_beg, page_end - page_beg); 143 } 144 } 145 } 146 147 void SetOrigin(const void *dst, uptr size, u32 origin) { 148 // Origin mapping is 4 bytes per 4 bytes of application memory. 149 // Here we extend the range such that its left and right bounds are both 150 // 4 byte aligned. 151 uptr x = MEM_TO_ORIGIN((uptr)dst); 152 uptr beg = x & ~3UL; // align down. 153 uptr end = (x + size + 3) & ~3UL; // align up. 154 u64 origin64 = ((u64)origin << 32) | origin; 155 // This is like memset, but the value is 32-bit. We unroll by 2 to write 156 // 64 bits at once. May want to unroll further to get 128-bit stores. 157 if (beg & 7ULL) { 158 *(u32 *)beg = origin; 159 beg += 4; 160 } 161 for (uptr addr = beg; addr < (end & ~7UL); addr += 8) *(u64 *)addr = origin64; 162 if (end & 7ULL) *(u32 *)(end - 4) = origin; 163 } 164 165 void PoisonMemory(const void *dst, uptr size, StackTrace *stack) { 166 SetShadow(dst, size, (u8)-1); 167 168 if (__msan_get_track_origins()) { 169 Origin o = Origin::CreateHeapOrigin(stack); 170 SetOrigin(dst, size, o.raw_id()); 171 } 172 } 173 174 } // namespace __msan 175
