1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
|
/*
* Copyright (C) 2020 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "libdebuggerd/gwp_asan.h"
#include "libdebuggerd/tombstone.h"
#include "libdebuggerd/utility.h"
#include "gwp_asan/common.h"
#include "gwp_asan/crash_handler.h"
#include <unwindstack/Maps.h>
#include <unwindstack/Memory.h>
#include <unwindstack/Regs.h>
#include <unwindstack/Unwinder.h>
#include "tombstone.pb.h"
// Retrieve GWP-ASan state from `state_addr` inside the process at
// `process_memory`. Place the state into `*state`.
static bool retrieve_gwp_asan_state(unwindstack::Memory* process_memory, uintptr_t state_addr,
gwp_asan::AllocatorState* state) {
return process_memory->ReadFully(state_addr, state, sizeof(*state));
}
// Retrieve the GWP-ASan metadata pool from `metadata_addr` inside the process
// at `process_memory`. The number of metadata slots is retrieved from the
// allocator state provided. This function returns a heap-allocated copy of the
// metadata pool whose ownership should be managed by the caller. Returns
// nullptr on failure.
static const gwp_asan::AllocationMetadata* retrieve_gwp_asan_metadata(
unwindstack::Memory* process_memory, const gwp_asan::AllocatorState& state,
uintptr_t metadata_addr) {
// 1 million GWP-ASan slots would take 4.1GiB of space. Thankfully, copying
// the metadata for that amount of slots is only 532MiB, and this really will
// only be used with some ridiculous torture-tests.
if (state.MaxSimultaneousAllocations > 1000000) {
ALOGE(
"Error when retrieving GWP-ASan metadata, MSA from state (%zu) "
"exceeds maximum allowed (1,000,000).",
state.MaxSimultaneousAllocations);
return nullptr;
}
gwp_asan::AllocationMetadata* meta =
new gwp_asan::AllocationMetadata[state.MaxSimultaneousAllocations];
if (!process_memory->ReadFully(metadata_addr, meta,
sizeof(*meta) * state.MaxSimultaneousAllocations)) {
ALOGE(
"Error when retrieving GWP-ASan metadata, could not retrieve %zu "
"pieces of metadata.",
state.MaxSimultaneousAllocations);
delete[] meta;
meta = nullptr;
}
return meta;
}
GwpAsanCrashData::GwpAsanCrashData(unwindstack::Memory* process_memory,
const ProcessInfo& process_info, const ThreadInfo& thread_info) {
if (!process_memory || !process_info.gwp_asan_metadata || !process_info.gwp_asan_state) return;
// Extract the GWP-ASan regions from the dead process.
if (!retrieve_gwp_asan_state(process_memory, process_info.gwp_asan_state, &state_)) return;
metadata_.reset(retrieve_gwp_asan_metadata(process_memory, state_, process_info.gwp_asan_metadata));
if (!metadata_.get()) return;
// Get the external crash address from the thread info.
crash_address_ = 0u;
if (process_info.has_fault_address) {
crash_address_ = process_info.untagged_fault_address;
}
// Ensure the error belongs to GWP-ASan.
if (!__gwp_asan_error_is_mine(&state_, crash_address_)) return;
is_gwp_asan_responsible_ = true;
thread_id_ = thread_info.tid;
// Grab the internal error address, if it exists.
uintptr_t internal_crash_address = __gwp_asan_get_internal_crash_address(&state_);
if (internal_crash_address) {
crash_address_ = internal_crash_address;
}
// Get other information from the internal state.
error_ = __gwp_asan_diagnose_error(&state_, metadata_.get(), crash_address_);
error_string_ = gwp_asan::ErrorToString(error_);
responsible_allocation_ = __gwp_asan_get_metadata(&state_, metadata_.get(), crash_address_);
}
bool GwpAsanCrashData::CrashIsMine() const {
return is_gwp_asan_responsible_;
}
constexpr size_t kMaxTraceLength = gwp_asan::AllocationMetadata::kMaxTraceLengthToCollect;
void GwpAsanCrashData::AddCauseProtos(Tombstone* tombstone, unwindstack::Unwinder* unwinder) const {
if (!CrashIsMine()) {
ALOGE("Internal Error: AddCauseProtos() on a non-GWP-ASan crash.");
return;
}
Cause* cause = tombstone->add_causes();
MemoryError* memory_error = cause->mutable_memory_error();
HeapObject* heap_object = memory_error->mutable_heap();
memory_error->set_tool(MemoryError_Tool_GWP_ASAN);
switch (error_) {
case gwp_asan::Error::USE_AFTER_FREE:
memory_error->set_type(MemoryError_Type_USE_AFTER_FREE);
break;
case gwp_asan::Error::DOUBLE_FREE:
memory_error->set_type(MemoryError_Type_DOUBLE_FREE);
break;
case gwp_asan::Error::INVALID_FREE:
memory_error->set_type(MemoryError_Type_INVALID_FREE);
break;
case gwp_asan::Error::BUFFER_OVERFLOW:
memory_error->set_type(MemoryError_Type_BUFFER_OVERFLOW);
break;
case gwp_asan::Error::BUFFER_UNDERFLOW:
memory_error->set_type(MemoryError_Type_BUFFER_UNDERFLOW);
break;
default:
memory_error->set_type(MemoryError_Type_UNKNOWN);
break;
}
heap_object->set_address(__gwp_asan_get_allocation_address(responsible_allocation_));
heap_object->set_size(__gwp_asan_get_allocation_size(responsible_allocation_));
unwinder->SetDisplayBuildID(true);
std::unique_ptr<uintptr_t[]> frames(new uintptr_t[kMaxTraceLength]);
heap_object->set_allocation_tid(__gwp_asan_get_allocation_thread_id(responsible_allocation_));
size_t num_frames =
__gwp_asan_get_allocation_trace(responsible_allocation_, frames.get(), kMaxTraceLength);
for (size_t i = 0; i != num_frames; ++i) {
unwindstack::FrameData frame_data = unwinder->BuildFrameFromPcOnly(frames[i]);
BacktraceFrame* f = heap_object->add_allocation_backtrace();
fill_in_backtrace_frame(f, frame_data);
}
heap_object->set_deallocation_tid(__gwp_asan_get_deallocation_thread_id(responsible_allocation_));
num_frames =
__gwp_asan_get_deallocation_trace(responsible_allocation_, frames.get(), kMaxTraceLength);
for (size_t i = 0; i != num_frames; ++i) {
unwindstack::FrameData frame_data = unwinder->BuildFrameFromPcOnly(frames[i]);
BacktraceFrame* f = heap_object->add_deallocation_backtrace();
fill_in_backtrace_frame(f, frame_data);
}
set_human_readable_cause(cause, crash_address_);
}
|
