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// Copyright (c) 2010 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 "chrome/renderer/safe_browsing/phishing_classifier.h"
#include <string>
#include "base/callback.h"
#include "base/compiler_specific.h"
#include "base/logging.h"
#include "base/sha2.h"
#include "chrome/renderer/render_view.h"
#include "chrome/renderer/safe_browsing/feature_extractor_clock.h"
#include "chrome/renderer/safe_browsing/features.h"
#include "chrome/renderer/safe_browsing/phishing_dom_feature_extractor.h"
#include "chrome/renderer/safe_browsing/phishing_term_feature_extractor.h"
#include "chrome/renderer/safe_browsing/phishing_url_feature_extractor.h"
#include "chrome/renderer/safe_browsing/scorer.h"
#include "googleurl/src/gurl.h"
#include "third_party/WebKit/WebKit/chromium/public/WebFrame.h"
#include "third_party/WebKit/WebKit/chromium/public/WebURL.h"
#include "third_party/WebKit/WebKit/chromium/public/WebView.h"
namespace safe_browsing {
const double PhishingClassifier::kInvalidScore = -1.0;
const double PhishingClassifier::kPhishyThreshold = 0.5;
PhishingClassifier::PhishingClassifier(RenderView* render_view,
const Scorer* scorer,
FeatureExtractorClock* clock)
: render_view_(render_view),
scorer_(scorer),
clock_(clock),
ALLOW_THIS_IN_INITIALIZER_LIST(method_factory_(this)) {
url_extractor_.reset(new PhishingUrlFeatureExtractor);
dom_extractor_.reset(
new PhishingDOMFeatureExtractor(render_view_, clock_.get()));
term_extractor_.reset(new PhishingTermFeatureExtractor(
&scorer_->page_terms(),
&scorer_->page_words(),
scorer_->max_words_per_term(),
clock_.get()));
Clear();
}
PhishingClassifier::~PhishingClassifier() {
// The RenderView should have called CancelPendingClassification() before
// we are destroyed.
CheckNoPendingClassification();
}
void PhishingClassifier::BeginClassification(const string16* page_text,
DoneCallback* done_callback) {
// The RenderView should have called CancelPendingClassification() before
// starting a new classification, so DCHECK this.
CheckNoPendingClassification();
// However, in an opt build, we will go ahead and clean up the pending
// classification so that we can start in a known state.
CancelPendingClassification();
page_text_ = page_text;
done_callback_.reset(done_callback);
// For consistency, we always want to invoke the DoneCallback
// asynchronously, rather than directly from this method. To ensure that
// this is the case, post a task to begin feature extraction on the next
// iteration of the message loop.
MessageLoop::current()->PostTask(
FROM_HERE,
method_factory_.NewRunnableMethod(
&PhishingClassifier::BeginFeatureExtraction));
}
void PhishingClassifier::BeginFeatureExtraction() {
WebKit::WebView* web_view = render_view_->webview();
if (!web_view) {
RunFailureCallback();
return;
}
WebKit::WebFrame* frame = web_view->mainFrame();
if (!frame) {
RunFailureCallback();
return;
}
features_.reset(new FeatureMap);
if (!url_extractor_->ExtractFeatures(GURL(frame->url()), features_.get())) {
RunFailureCallback();
return;
}
// DOM feature extraction can take awhile, so it runs asynchronously
// in several chunks of work and invokes the callback when finished.
dom_extractor_->ExtractFeatures(
features_.get(),
NewCallback(this, &PhishingClassifier::DOMExtractionFinished));
}
void PhishingClassifier::CancelPendingClassification() {
// Note that cancelling the feature extractors is simply a no-op if they
// were not running.
dom_extractor_->CancelPendingExtraction();
term_extractor_->CancelPendingExtraction();
method_factory_.RevokeAll();
Clear();
}
void PhishingClassifier::DOMExtractionFinished(bool success) {
if (success) {
// Term feature extraction can take awhile, so it runs asynchronously
// in several chunks of work and invokes the callback when finished.
term_extractor_->ExtractFeatures(
page_text_,
features_.get(),
NewCallback(this, &PhishingClassifier::TermExtractionFinished));
} else {
RunFailureCallback();
}
}
void PhishingClassifier::TermExtractionFinished(bool success) {
if (success) {
// Hash all of the features so that they match the model, then compute
// the score.
FeatureMap hashed_features;
for (base::hash_map<std::string, double>::const_iterator it =
features_->features().begin();
it != features_->features().end(); ++it) {
DCHECK(hashed_features.AddRealFeature(base::SHA256HashString(it->first),
it->second));
}
double score = scorer_->ComputeScore(hashed_features);
RunCallback(score >= kPhishyThreshold, score);
} else {
RunFailureCallback();
}
}
void PhishingClassifier::CheckNoPendingClassification() {
DCHECK(!done_callback_.get());
DCHECK(!page_text_);
if (done_callback_.get() || page_text_) {
LOG(ERROR) << "Classification in progress, missing call to "
<< "CancelPendingClassification";
}
}
void PhishingClassifier::RunCallback(bool phishy, double phishy_score) {
done_callback_->Run(phishy, phishy_score);
Clear();
}
void PhishingClassifier::RunFailureCallback() {
RunCallback(false /* not phishy */, kInvalidScore);
}
void PhishingClassifier::Clear() {
page_text_ = NULL;
done_callback_.reset(NULL);
features_.reset(NULL);
}
} // namespace safe_browsing
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