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
FindInfoForStackVar(uptr addr,const char * frame_descr,uptr offset,char * name,uptr name_size,uptr * region_address,uptr * region_size)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
AsanGetStack(uptr addr,uptr * trace,u32 size,u32 * thread_id,bool alloc_stack)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
__asan_locate_address(uptr addr,char * name,uptr name_size,uptr * region_address_ptr,uptr * region_size_ptr)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
__asan_get_alloc_stack(uptr addr,uptr * trace,uptr size,u32 * thread_id)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
__asan_get_free_stack(uptr addr,uptr * trace,uptr size,u32 * thread_id)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
__asan_get_shadow_mapping(uptr * shadow_scale,uptr * shadow_offset)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