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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "extensions/browser/content_verify_job.h"
#include <algorithm>
#include "base/metrics/histogram.h"
#include "base/stl_util.h"
#include "base/task_runner_util.h"
#include "base/timer/elapsed_timer.h"
#include "content/public/browser/browser_thread.h"
#include "crypto/secure_hash.h"
#include "crypto/sha2.h"
#include "extensions/browser/content_hash_reader.h"
namespace extensions {
namespace {
ContentVerifyJob::TestDelegate* g_test_delegate = NULL;
ContentVerifyJob::TestObserver* g_test_observer = NULL;
class ScopedElapsedTimer {
public:
ScopedElapsedTimer(base::TimeDelta* total) : total_(total) { DCHECK(total_); }
~ScopedElapsedTimer() { *total_ += timer.Elapsed(); }
private:
// Some total amount of time we should add our elapsed time to at
// destruction.
base::TimeDelta* total_;
// A timer for how long this object has been alive.
base::ElapsedTimer timer;
};
} // namespace
ContentVerifyJob::ContentVerifyJob(ContentHashReader* hash_reader,
const FailureCallback& failure_callback)
: done_reading_(false),
hashes_ready_(false),
total_bytes_read_(0),
current_block_(0),
current_hash_byte_count_(0),
hash_reader_(hash_reader),
failure_callback_(failure_callback),
failed_(false) {
// It's ok for this object to be constructed on a different thread from where
// it's used.
thread_checker_.DetachFromThread();
}
ContentVerifyJob::~ContentVerifyJob() {
UMA_HISTOGRAM_COUNTS("ExtensionContentVerifyJob.TimeSpentUS",
time_spent_.InMicroseconds());
}
void ContentVerifyJob::Start() {
DCHECK(thread_checker_.CalledOnValidThread());
if (g_test_observer)
g_test_observer->JobStarted(hash_reader_->extension_id(),
hash_reader_->relative_path());
base::PostTaskAndReplyWithResult(
content::BrowserThread::GetBlockingPool(),
FROM_HERE,
base::Bind(&ContentHashReader::Init, hash_reader_),
base::Bind(&ContentVerifyJob::OnHashesReady, this));
}
void ContentVerifyJob::BytesRead(int count, const char* data) {
ScopedElapsedTimer timer(&time_spent_);
DCHECK(thread_checker_.CalledOnValidThread());
if (failed_)
return;
if (g_test_delegate) {
FailureReason reason =
g_test_delegate->BytesRead(hash_reader_->extension_id(), count, data);
if (reason != NONE)
return DispatchFailureCallback(reason);
}
if (!hashes_ready_) {
queue_.append(data, count);
return;
}
DCHECK_GE(count, 0);
int bytes_added = 0;
while (bytes_added < count) {
if (current_block_ >= hash_reader_->block_count())
return DispatchFailureCallback(HASH_MISMATCH);
if (!current_hash_.get()) {
current_hash_byte_count_ = 0;
current_hash_.reset(
crypto::SecureHash::Create(crypto::SecureHash::SHA256));
}
// Compute how many bytes we should hash, and add them to the current hash.
int bytes_to_hash =
std::min(hash_reader_->block_size() - current_hash_byte_count_,
count - bytes_added);
DCHECK(bytes_to_hash > 0);
current_hash_->Update(data + bytes_added, bytes_to_hash);
bytes_added += bytes_to_hash;
current_hash_byte_count_ += bytes_to_hash;
total_bytes_read_ += bytes_to_hash;
// If we finished reading a block worth of data, finish computing the hash
// for it and make sure the expected hash matches.
if (current_hash_byte_count_ == hash_reader_->block_size() &&
!FinishBlock()) {
DispatchFailureCallback(HASH_MISMATCH);
return;
}
}
}
void ContentVerifyJob::DoneReading() {
ScopedElapsedTimer timer(&time_spent_);
DCHECK(thread_checker_.CalledOnValidThread());
if (failed_)
return;
if (g_test_delegate) {
FailureReason reason =
g_test_delegate->DoneReading(hash_reader_->extension_id());
if (reason != NONE) {
DispatchFailureCallback(reason);
return;
}
}
done_reading_ = true;
if (hashes_ready_) {
if (!FinishBlock())
DispatchFailureCallback(HASH_MISMATCH);
else if (g_test_observer)
g_test_observer->JobFinished(hash_reader_->extension_id(),
hash_reader_->relative_path(), failed_);
}
}
bool ContentVerifyJob::FinishBlock() {
if (current_hash_byte_count_ <= 0)
return true;
std::string final(crypto::kSHA256Length, 0);
current_hash_->Finish(string_as_array(&final), final.size());
current_hash_.reset();
current_hash_byte_count_ = 0;
int block = current_block_++;
const std::string* expected_hash = NULL;
if (!hash_reader_->GetHashForBlock(block, &expected_hash) ||
*expected_hash != final)
return false;
return true;
}
void ContentVerifyJob::OnHashesReady(bool success) {
if (!success && !g_test_delegate) {
if (!hash_reader_->content_exists()) {
// Ignore verification of non-existent resources.
return;
} else if (hash_reader_->have_verified_contents() &&
hash_reader_->have_computed_hashes()) {
DispatchFailureCallback(NO_HASHES_FOR_FILE);
} else {
DispatchFailureCallback(MISSING_ALL_HASHES);
}
return;
}
hashes_ready_ = true;
if (!queue_.empty()) {
std::string tmp;
queue_.swap(tmp);
BytesRead(tmp.size(), string_as_array(&tmp));
}
if (done_reading_) {
ScopedElapsedTimer timer(&time_spent_);
if (!FinishBlock())
DispatchFailureCallback(HASH_MISMATCH);
else if (g_test_observer) {
g_test_observer->JobFinished(hash_reader_->extension_id(),
hash_reader_->relative_path(), failed_);
}
}
}
// static
void ContentVerifyJob::SetDelegateForTests(TestDelegate* delegate) {
g_test_delegate = delegate;
}
// static
void ContentVerifyJob::SetObserverForTests(TestObserver* observer) {
g_test_observer = observer;
}
void ContentVerifyJob::DispatchFailureCallback(FailureReason reason) {
DCHECK(!failed_);
failed_ = true;
if (!failure_callback_.is_null()) {
VLOG(1) << "job failed for " << hash_reader_->extension_id() << " "
<< hash_reader_->relative_path().MaybeAsASCII()
<< " reason:" << reason;
failure_callback_.Run(reason);
failure_callback_.Reset();
}
if (g_test_observer)
g_test_observer->JobFinished(
hash_reader_->extension_id(), hash_reader_->relative_path(), failed_);
}
} // namespace extensions
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