1 //===-- asan_debugging.cpp ------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file is a part of AddressSanitizer, an address sanity checker. 10 // 11 // This file contains various functions that are generally useful to call when 12 // using a debugger (LLDB, GDB). 13 //===----------------------------------------------------------------------===// 14 15 #include "asan_allocator.h" 16 #include "asan_descriptions.h" 17 #include "asan_flags.h" 18 #include "asan_internal.h" 19 #include "asan_mapping.h" 20 #include "asan_report.h" 21 #include "asan_thread.h" 22 #include "sanitizer_common/sanitizer_stackdepot.h" 23 24 namespace { 25 using namespace __asan; 26 27 static void FindInfoForStackVar(uptr addr, const char *frame_descr, uptr offset, 28 char *name, uptr name_size, 29 uptr *region_address, uptr *region_size) { 30 InternalMmapVector<StackVarDescr> vars; 31 vars.reserve(16); 32 if (!ParseFrameDescription(frame_descr, &vars)) { 33 return; 34 } 35 36 for (uptr i = 0; i < vars.size(); i++) { 37 if (offset <= vars[i].beg + vars[i].size) { 38 // We use name_len + 1 because strlcpy will guarantee a \0 at the end, so 39 // if we're limiting the copy due to name_len, we add 1 to ensure we copy 40 // the whole name and then terminate with '\0'. 41 internal_strlcpy(name, vars[i].name_pos, 42 Min(name_size, vars[i].name_len + 1)); 43 *region_address = addr - (offset - vars[i].beg); 44 *region_size = vars[i].size; 45 return; 46 } 47 } 48 } 49 50 uptr AsanGetStack(uptr addr, uptr *trace, u32 size, u32 *thread_id, 51 bool alloc_stack) { 52 AsanChunkView chunk = FindHeapChunkByAddress(addr); 53 if (!chunk.IsValid()) return 0; 54 55 StackTrace stack(nullptr, 0); 56 if (alloc_stack) { 57 if (chunk.AllocTid() == kInvalidTid) return 0; 58 stack = StackDepotGet(chunk.GetAllocStackId()); 59 if (thread_id) *thread_id = chunk.AllocTid(); 60 } else { 61 if (chunk.FreeTid() == kInvalidTid) return 0; 62 stack = StackDepotGet(chunk.GetFreeStackId()); 63 if (thread_id) *thread_id = chunk.FreeTid(); 64 } 65 66 if (trace && size) { 67 size = Min(size, Min(stack.size, kStackTraceMax)); 68 for (uptr i = 0; i < size; i++) 69 trace[i] = StackTrace::GetPreviousInstructionPc(stack.trace[i]); 70 71 return size; 72 } 73 74 return 0; 75 } 76 77 } // namespace 78 79 SANITIZER_INTERFACE_ATTRIBUTE 80 const char *__asan_locate_address(uptr addr, char *name, uptr name_size, 81 uptr *region_address_ptr, 82 uptr *region_size_ptr) { 83 AddressDescription descr(addr); 84 uptr region_address = 0; 85 uptr region_size = 0; 86 const char *region_kind = nullptr; 87 if (name && name_size > 0) name[0] = 0; 88 89 if (auto shadow = descr.AsShadow()) { 90 // region_{address,size} are already 0 91 switch (shadow->kind) { 92 case kShadowKindLow: 93 region_kind = "low shadow"; 94 break; 95 case kShadowKindGap: 96 region_kind = "shadow gap"; 97 break; 98 case kShadowKindHigh: 99 region_kind = "high shadow"; 100 break; 101 } 102 } else if (auto heap = descr.AsHeap()) { 103 region_kind = "heap"; 104 region_address = heap->chunk_access.chunk_begin; 105 region_size = heap->chunk_access.chunk_size; 106 } else if (auto stack = descr.AsStack()) { 107 region_kind = "stack"; 108 if (!stack->frame_descr) { 109 // region_{address,size} are already 0 110 } else { 111 FindInfoForStackVar(addr, stack->frame_descr, stack->offset, name, 112 name_size, ®ion_address, ®ion_size); 113 } 114 } else if (auto global = descr.AsGlobal()) { 115 region_kind = "global"; 116 auto &g = global->globals[0]; 117 internal_strlcpy(name, g.name, name_size); 118 region_address = g.beg; 119 region_size = g.size; 120 } else { 121 // region_{address,size} are already 0 122 region_kind = "heap-invalid"; 123 } 124 125 CHECK(region_kind); 126 if (region_address_ptr) *region_address_ptr = region_address; 127 if (region_size_ptr) *region_size_ptr = region_size; 128 return region_kind; 129 } 130 131 SANITIZER_INTERFACE_ATTRIBUTE 132 uptr __asan_get_alloc_stack(uptr addr, uptr *trace, uptr size, u32 *thread_id) { 133 return AsanGetStack(addr, trace, size, thread_id, /* alloc_stack */ true); 134 } 135 136 SANITIZER_INTERFACE_ATTRIBUTE 137 uptr __asan_get_free_stack(uptr addr, uptr *trace, uptr size, u32 *thread_id) { 138 return AsanGetStack(addr, trace, size, thread_id, /* alloc_stack */ false); 139 } 140 141 SANITIZER_INTERFACE_ATTRIBUTE 142 void __asan_get_shadow_mapping(uptr *shadow_scale, uptr *shadow_offset) { 143 if (shadow_scale) 144 *shadow_scale = ASAN_SHADOW_SCALE; 145 if (shadow_offset) 146 *shadow_offset = ASAN_SHADOW_OFFSET; 147 } 148