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 23 namespace { 24 using namespace __asan; 25 26 static void FindInfoForStackVar(uptr addr, const char *frame_descr, uptr offset, 27 char *name, uptr name_size, 28 uptr *region_address, uptr *region_size) { 29 InternalMmapVector<StackVarDescr> vars; 30 vars.reserve(16); 31 if (!ParseFrameDescription(frame_descr, &vars)) { 32 return; 33 } 34 35 for (uptr i = 0; i < vars.size(); i++) { 36 if (offset <= vars[i].beg + vars[i].size) { 37 // We use name_len + 1 because strlcpy will guarantee a \0 at the end, so 38 // if we're limiting the copy due to name_len, we add 1 to ensure we copy 39 // the whole name and then terminate with '\0'. 40 internal_strlcpy(name, vars[i].name_pos, 41 Min(name_size, vars[i].name_len + 1)); 42 *region_address = addr - (offset - vars[i].beg); 43 *region_size = vars[i].size; 44 return; 45 } 46 } 47 } 48 49 uptr AsanGetStack(uptr addr, uptr *trace, u32 size, u32 *thread_id, 50 bool alloc_stack) { 51 AsanChunkView chunk = FindHeapChunkByAddress(addr); 52 if (!chunk.IsValid()) return 0; 53 54 StackTrace stack(nullptr, 0); 55 if (alloc_stack) { 56 if (chunk.AllocTid() == kInvalidTid) return 0; 57 stack = chunk.GetAllocStack(); 58 if (thread_id) *thread_id = chunk.AllocTid(); 59 } else { 60 if (chunk.FreeTid() == kInvalidTid) return 0; 61 stack = chunk.GetFreeStack(); 62 if (thread_id) *thread_id = chunk.FreeTid(); 63 } 64 65 if (trace && size) { 66 size = Min(size, Min(stack.size, kStackTraceMax)); 67 for (uptr i = 0; i < size; i++) 68 trace[i] = StackTrace::GetPreviousInstructionPc(stack.trace[i]); 69 70 return size; 71 } 72 73 return 0; 74 } 75 76 } // namespace 77 78 SANITIZER_INTERFACE_ATTRIBUTE 79 const char *__asan_locate_address(uptr addr, char *name, uptr name_size, 80 uptr *region_address_ptr, 81 uptr *region_size_ptr) { 82 AddressDescription descr(addr); 83 uptr region_address = 0; 84 uptr region_size = 0; 85 const char *region_kind = nullptr; 86 if (name && name_size > 0) name[0] = 0; 87 88 if (auto shadow = descr.AsShadow()) { 89 // region_{address,size} are already 0 90 switch (shadow->kind) { 91 case kShadowKindLow: 92 region_kind = "low shadow"; 93 break; 94 case kShadowKindGap: 95 region_kind = "shadow gap"; 96 break; 97 case kShadowKindHigh: 98 region_kind = "high shadow"; 99 break; 100 } 101 } else if (auto heap = descr.AsHeap()) { 102 region_kind = "heap"; 103 region_address = heap->chunk_access.chunk_begin; 104 region_size = heap->chunk_access.chunk_size; 105 } else if (auto stack = descr.AsStack()) { 106 region_kind = "stack"; 107 if (!stack->frame_descr) { 108 // region_{address,size} are already 0 109 } else { 110 FindInfoForStackVar(addr, stack->frame_descr, stack->offset, name, 111 name_size, ®ion_address, ®ion_size); 112 } 113 } else if (auto global = descr.AsGlobal()) { 114 region_kind = "global"; 115 auto &g = global->globals[0]; 116 internal_strlcpy(name, g.name, name_size); 117 region_address = g.beg; 118 region_size = g.size; 119 } else { 120 // region_{address,size} are already 0 121 region_kind = "heap-invalid"; 122 } 123 124 CHECK(region_kind); 125 if (region_address_ptr) *region_address_ptr = region_address; 126 if (region_size_ptr) *region_size_ptr = region_size; 127 return region_kind; 128 } 129 130 SANITIZER_INTERFACE_ATTRIBUTE 131 uptr __asan_get_alloc_stack(uptr addr, uptr *trace, uptr size, u32 *thread_id) { 132 return AsanGetStack(addr, trace, size, thread_id, /* alloc_stack */ true); 133 } 134 135 SANITIZER_INTERFACE_ATTRIBUTE 136 uptr __asan_get_free_stack(uptr addr, uptr *trace, uptr size, u32 *thread_id) { 137 return AsanGetStack(addr, trace, size, thread_id, /* alloc_stack */ false); 138 } 139 140 SANITIZER_INTERFACE_ATTRIBUTE 141 void __asan_get_shadow_mapping(uptr *shadow_scale, uptr *shadow_offset) { 142 if (shadow_scale) 143 *shadow_scale = SHADOW_SCALE; 144 if (shadow_offset) 145 *shadow_offset = SHADOW_OFFSET; 146 } 147