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
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
|
// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "gin/array_buffer.h"
#include <stddef.h>
#include <stdlib.h>
#include "base/allocator/partition_allocator/page_allocator.h"
#include "base/allocator/partition_allocator/partition_alloc.h"
#include "base/bits.h"
#include "base/check_op.h"
#include "base/no_destructor.h"
#include "build/build_config.h"
#include "gin/per_isolate_data.h"
#include "v8/include/v8-initialization.h"
#if BUILDFLAG(IS_POSIX)
#include <sys/mman.h>
#ifndef MAP_ANONYMOUS
#define MAP_ANONYMOUS MAP_ANON
#endif
#endif // BUILDFLAG(IS_POSIX)
namespace gin {
static_assert(V8_ARRAY_BUFFER_INTERNAL_FIELD_COUNT == 2,
"array buffers must have two internal fields");
// ArrayBufferAllocator -------------------------------------------------------
partition_alloc::ThreadSafePartitionRoot* ArrayBufferAllocator::partition_ =
nullptr;
void* ArrayBufferAllocator::Allocate(size_t length) {
unsigned int flags = partition_alloc::AllocFlags::kZeroFill |
partition_alloc::AllocFlags::kReturnNull;
return AllocateInternal(length, flags);
}
void* ArrayBufferAllocator::AllocateUninitialized(size_t length) {
unsigned int flags = partition_alloc::AllocFlags::kReturnNull;
return AllocateInternal(length, flags);
}
void* ArrayBufferAllocator::AllocateInternal(size_t length,
unsigned int flags) {
#ifdef V8_ENABLE_SANDBOX
// The V8 sandbox requires all ArrayBuffer backing stores to be allocated
// inside the sandbox address space. This isn't guaranteed if allocation
// override hooks (which are e.g. used by GWP-ASan) are enabled or if a
// memory tool (e.g. ASan) overrides malloc, so disable both.
flags |= partition_alloc::AllocFlags::kNoOverrideHooks;
flags |= partition_alloc::AllocFlags::kNoMemoryToolOverride;
#endif
return partition_->AllocWithFlags(flags, length, "gin::ArrayBufferAllocator");
}
void ArrayBufferAllocator::Free(void* data, size_t length) {
unsigned int flags = 0;
#ifdef V8_ENABLE_SANDBOX
// See |AllocateInternal|.
flags |= partition_alloc::FreeFlags::kNoMemoryToolOverride;
#endif
partition_->FreeWithFlags(flags, data);
}
// static
ArrayBufferAllocator* ArrayBufferAllocator::SharedInstance() {
static ArrayBufferAllocator* instance = new ArrayBufferAllocator();
return instance;
}
// static
void ArrayBufferAllocator::InitializePartition() {
static base::NoDestructor<partition_alloc::PartitionAllocator>
partition_allocator{};
// These configuration options are copied from blink's ArrayBufferPartition.
partition_allocator->init({
partition_alloc::PartitionOptions::AlignedAlloc::kDisallowed,
partition_alloc::PartitionOptions::ThreadCache::kDisabled,
partition_alloc::PartitionOptions::Quarantine::kAllowed,
partition_alloc::PartitionOptions::Cookie::kAllowed,
partition_alloc::PartitionOptions::BackupRefPtr::kDisabled,
partition_alloc::PartitionOptions::BackupRefPtrZapping::kDisabled,
partition_alloc::PartitionOptions::UseConfigurablePool::kIfAvailable,
});
partition_ = partition_allocator->root();
}
// ArrayBuffer ----------------------------------------------------------------
ArrayBuffer::ArrayBuffer() = default;
ArrayBuffer::ArrayBuffer(v8::Isolate* isolate, v8::Local<v8::ArrayBuffer> array)
: backing_store_(array->GetBackingStore()) {}
ArrayBuffer::~ArrayBuffer() = default;
ArrayBuffer& ArrayBuffer::operator=(const ArrayBuffer& other) = default;
// Converter<ArrayBuffer> -----------------------------------------------------
bool Converter<ArrayBuffer>::FromV8(v8::Isolate* isolate,
v8::Local<v8::Value> val,
ArrayBuffer* out) {
if (!val->IsArrayBuffer())
return false;
*out = ArrayBuffer(isolate, v8::Local<v8::ArrayBuffer>::Cast(val));
return true;
}
// ArrayBufferView ------------------------------------------------------------
ArrayBufferView::ArrayBufferView()
: offset_(0),
num_bytes_(0) {
}
ArrayBufferView::ArrayBufferView(v8::Isolate* isolate,
v8::Local<v8::ArrayBufferView> view)
: array_buffer_(isolate, view->Buffer()),
offset_(view->ByteOffset()),
num_bytes_(view->ByteLength()) {
}
ArrayBufferView::~ArrayBufferView() = default;
ArrayBufferView& ArrayBufferView::operator=(const ArrayBufferView& other) =
default;
// Converter<ArrayBufferView> -------------------------------------------------
bool Converter<ArrayBufferView>::FromV8(v8::Isolate* isolate,
v8::Local<v8::Value> val,
ArrayBufferView* out) {
if (!val->IsArrayBufferView())
return false;
*out = ArrayBufferView(isolate, v8::Local<v8::ArrayBufferView>::Cast(val));
return true;
}
// ArrayBufferSharedMemoryMapper ---------------------------------------------
namespace {
#ifdef V8_ENABLE_SANDBOX
// When the V8 sandbox is enabled, shared memory backing ArrayBuffers must be
// mapped into the sandbox address space. This custom SharedMemoryMapper
// implements this.
class ArrayBufferSharedMemoryMapper : public base::SharedMemoryMapper {
public:
absl::optional<base::span<uint8_t>> Map(
base::subtle::PlatformSharedMemoryHandle handle,
bool write_allowed,
uint64_t offset,
size_t size) override {
v8::VirtualAddressSpace* address_space = v8::V8::GetSandboxAddressSpace();
size_t allocation_granularity = address_space->allocation_granularity();
v8::PlatformSharedMemoryHandle v8_handle;
#if BUILDFLAG(IS_MAC)
v8_handle = v8::SharedMemoryHandleFromMachMemoryEntry(handle);
#elif BUILDFLAG(IS_FUCHSIA)
v8_handle = v8::SharedMemoryHandleFromVMO(handle->get());
#elif BUILDFLAG(IS_WIN)
v8_handle = v8::SharedMemoryHandleFromFileMapping(handle);
#elif BUILDFLAG(IS_ANDROID)
v8_handle = v8::SharedMemoryHandleFromFileDescriptor(handle);
#elif BUILDFLAG(IS_POSIX)
v8_handle = v8::SharedMemoryHandleFromFileDescriptor(handle.fd);
#else
#error "Unknown platform"
#endif
// Size and offset must be a multiple of the page allocation granularity.
// The caller already ensures that the offset is a multiple of the
// allocation granularity though.
CHECK_EQ(0UL, offset % allocation_granularity);
size_t mapping_size = base::bits::AlignUp(size, allocation_granularity);
v8::PagePermissions permissions = write_allowed
? v8::PagePermissions::kReadWrite
: v8::PagePermissions::kRead;
uintptr_t mapping = v8::V8::GetSandboxAddressSpace()->AllocateSharedPages(
0, mapping_size, permissions, v8_handle, offset);
if (!mapping)
return absl::nullopt;
return base::make_span(reinterpret_cast<uint8_t*>(mapping), size);
}
void Unmap(base::span<uint8_t> mapping) override {
v8::VirtualAddressSpace* address_space = v8::V8::GetSandboxAddressSpace();
size_t allocation_granularity = address_space->allocation_granularity();
uintptr_t address = reinterpret_cast<uintptr_t>(mapping.data());
CHECK_EQ(0UL, address % allocation_granularity);
size_t mapping_size =
base::bits::AlignUp(mapping.size(), allocation_granularity);
address_space->FreeSharedPages(address, mapping_size);
}
};
#endif // V8_ENABLE_SANDBOX
} // namespace
base::SharedMemoryMapper* GetSharedMemoryMapperForArrayBuffers() {
#if V8_ENABLE_SANDBOX
static ArrayBufferSharedMemoryMapper instance;
return &instance;
#else
return base::SharedMemoryMapper::GetDefaultInstance();
#endif
}
} // namespace gin
|
