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// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "net/shared_dictionary/shared_dictionary_header_checker_source_stream.h"
#include "base/check_op.h"
#include "base/containers/span.h"
#include "base/functional/callback_helpers.h"
#include "base/strings/string_number_conversions.h"
#include "net/base/hash_value.h"
#include "net/base/io_buffer.h"
#include "net/base/net_errors.h"
#include "net/filter/source_stream_type.h"
namespace net {
namespace {
static constexpr unsigned char kCompressionTypeBrotliSignature[] = {0xff, 0x44,
0x43, 0x42};
static constexpr unsigned char kCompressionTypeZstdSignature[] = {
0x5e, 0x2a, 0x4d, 0x18, 0x20, 0x00, 0x00, 0x00};
static constexpr size_t kCompressionTypeBrotliSignatureSize =
sizeof(kCompressionTypeBrotliSignature);
static constexpr size_t kCompressionTypeZstdSignatureSize =
sizeof(kCompressionTypeZstdSignature);
static constexpr size_t kCompressionDictionaryHashSize = 32;
static_assert(sizeof(SHA256HashValue) == kCompressionDictionaryHashSize,
"kCompressionDictionaryHashSize mismatch");
static constexpr size_t kCompressionTypeBrotliHeaderSize =
kCompressionTypeBrotliSignatureSize + kCompressionDictionaryHashSize;
static constexpr size_t kCompressionTypeZstdHeaderSize =
kCompressionTypeZstdSignatureSize + kCompressionDictionaryHashSize;
size_t GetSignatureSize(SharedDictionaryHeaderCheckerSourceStream::Type type) {
switch (type) {
case SharedDictionaryHeaderCheckerSourceStream::Type::
kDictionaryCompressedBrotli:
return kCompressionTypeBrotliSignatureSize;
case SharedDictionaryHeaderCheckerSourceStream::Type::
kDictionaryCompressedZstd:
return kCompressionTypeZstdSignatureSize;
}
}
size_t GetHeaderSize(SharedDictionaryHeaderCheckerSourceStream::Type type) {
switch (type) {
case SharedDictionaryHeaderCheckerSourceStream::Type::
kDictionaryCompressedBrotli:
return kCompressionTypeBrotliHeaderSize;
case SharedDictionaryHeaderCheckerSourceStream::Type::
kDictionaryCompressedZstd:
return kCompressionTypeZstdHeaderSize;
}
}
base::span<const unsigned char> GetExpectedSignature(
SharedDictionaryHeaderCheckerSourceStream::Type type) {
switch (type) {
case SharedDictionaryHeaderCheckerSourceStream::Type::
kDictionaryCompressedBrotli:
return kCompressionTypeBrotliSignature;
case SharedDictionaryHeaderCheckerSourceStream::Type::
kDictionaryCompressedZstd:
return kCompressionTypeZstdSignature;
}
}
} // namespace
SharedDictionaryHeaderCheckerSourceStream::
SharedDictionaryHeaderCheckerSourceStream(
std::unique_ptr<SourceStream> upstream,
Type type,
const SHA256HashValue& dictionary_hash)
: SourceStream(SourceStreamType::kNone),
upstream_(std::move(upstream)),
type_(type),
dictionary_hash_(dictionary_hash),
head_read_buffer_(base::MakeRefCounted<GrowableIOBuffer>()) {
head_read_buffer_->SetCapacity(GetHeaderSize(type_));
ReadHeader();
}
SharedDictionaryHeaderCheckerSourceStream::
~SharedDictionaryHeaderCheckerSourceStream() = default;
int SharedDictionaryHeaderCheckerSourceStream::Read(
IOBuffer* dest_buffer,
int buffer_size,
CompletionOnceCallback callback) {
if (header_check_result_ == OK) {
return upstream_->Read(dest_buffer, buffer_size, std::move(callback));
}
if (header_check_result_ == ERR_IO_PENDING) {
CHECK(head_read_buffer_);
// Still reading header.
pending_read_buf_ = dest_buffer;
pending_read_buf_len_ = buffer_size;
pending_callback_ = std::move(callback);
}
return header_check_result_;
}
std::string SharedDictionaryHeaderCheckerSourceStream::Description() const {
return "SharedDictionaryHeaderCheckerSourceStream";
}
bool SharedDictionaryHeaderCheckerSourceStream::MayHaveMoreBytes() const {
return upstream_->MayHaveMoreBytes();
}
void SharedDictionaryHeaderCheckerSourceStream::ReadHeader() {
int result = upstream_->Read(
head_read_buffer_.get(), head_read_buffer_->RemainingCapacity(),
base::BindOnce(
&SharedDictionaryHeaderCheckerSourceStream::OnReadCompleted,
base::Unretained(this)));
if (result != ERR_IO_PENDING) {
OnReadCompleted(result);
}
}
void SharedDictionaryHeaderCheckerSourceStream::OnReadCompleted(int result) {
CHECK_NE(result, ERR_IO_PENDING);
if (result <= 0) {
// OK means the stream is closed before reading header.
if (result == OK) {
result = ERR_UNEXPECTED_CONTENT_DICTIONARY_HEADER;
}
HeaderCheckCompleted(result);
return;
}
head_read_buffer_->set_offset(head_read_buffer_->offset() + result);
if (head_read_buffer_->RemainingCapacity() != 0) {
ReadHeader();
return;
}
HeaderCheckCompleted(
CheckHeaderBuffer() ? OK : ERR_UNEXPECTED_CONTENT_DICTIONARY_HEADER);
}
bool SharedDictionaryHeaderCheckerSourceStream::CheckHeaderBuffer() const {
CHECK(head_read_buffer_->RemainingCapacity() == 0);
if (GetSignatureInBuffer() != GetExpectedSignature(type_)) {
return false;
}
if (GetHashInBuffer() != dictionary_hash_) {
return false;
}
return true;
}
void SharedDictionaryHeaderCheckerSourceStream::HeaderCheckCompleted(
int header_check_result) {
CHECK_NE(header_check_result, ERR_IO_PENDING);
CHECK_EQ(header_check_result_, ERR_IO_PENDING);
header_check_result_ = header_check_result;
head_read_buffer_.reset();
if (!pending_callback_) {
return;
}
auto callback_split = base::SplitOnceCallback(std::move(pending_callback_));
int read_result = Read(pending_read_buf_.get(), pending_read_buf_len_,
std::move(callback_split.first));
if (read_result != ERR_IO_PENDING) {
std::move(callback_split.second).Run(read_result);
}
}
base::span<const unsigned char>
SharedDictionaryHeaderCheckerSourceStream::GetSignatureInBuffer() const {
return head_read_buffer_->everything().first(GetSignatureSize(type_));
}
base::span<const unsigned char>
SharedDictionaryHeaderCheckerSourceStream::GetHashInBuffer() const {
return head_read_buffer_->everything().subspan(
GetSignatureSize(type_), kCompressionDictionaryHashSize);
}
} // namespace net
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