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      1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "chrome/renderer/safe_browsing/phishing_classifier.h"
      6 
      7 #include <string>
      8 
      9 #include "base/bind.h"
     10 #include "base/callback.h"
     11 #include "base/compiler_specific.h"
     12 #include "base/logging.h"
     13 #include "base/message_loop/message_loop.h"
     14 #include "base/metrics/histogram.h"
     15 #include "base/strings/string_util.h"
     16 #include "chrome/common/safe_browsing/csd.pb.h"
     17 #include "chrome/common/url_constants.h"
     18 #include "chrome/renderer/safe_browsing/feature_extractor_clock.h"
     19 #include "chrome/renderer/safe_browsing/features.h"
     20 #include "chrome/renderer/safe_browsing/phishing_dom_feature_extractor.h"
     21 #include "chrome/renderer/safe_browsing/phishing_term_feature_extractor.h"
     22 #include "chrome/renderer/safe_browsing/phishing_url_feature_extractor.h"
     23 #include "chrome/renderer/safe_browsing/scorer.h"
     24 #include "content/public/renderer/render_view.h"
     25 #include "crypto/sha2.h"
     26 #include "third_party/WebKit/public/platform/WebURL.h"
     27 #include "third_party/WebKit/public/platform/WebURLRequest.h"
     28 #include "third_party/WebKit/public/web/WebDataSource.h"
     29 #include "third_party/WebKit/public/web/WebDocument.h"
     30 #include "third_party/WebKit/public/web/WebFrame.h"
     31 #include "third_party/WebKit/public/web/WebView.h"
     32 #include "url/gurl.h"
     33 
     34 namespace safe_browsing {
     35 
     36 const float PhishingClassifier::kInvalidScore = -1.0;
     37 const float PhishingClassifier::kPhishyThreshold = 0.5;
     38 
     39 PhishingClassifier::PhishingClassifier(content::RenderView* render_view,
     40                                        FeatureExtractorClock* clock)
     41     : render_view_(render_view),
     42       scorer_(NULL),
     43       clock_(clock),
     44       weak_factory_(this) {
     45   Clear();
     46 }
     47 
     48 PhishingClassifier::~PhishingClassifier() {
     49   // The RenderView should have called CancelPendingClassification() before
     50   // we are destroyed.
     51   CheckNoPendingClassification();
     52 }
     53 
     54 void PhishingClassifier::set_phishing_scorer(const Scorer* scorer) {
     55   CheckNoPendingClassification();
     56   scorer_ = scorer;
     57   if (scorer_) {
     58     url_extractor_.reset(new PhishingUrlFeatureExtractor);
     59     dom_extractor_.reset(
     60         new PhishingDOMFeatureExtractor(render_view_, clock_.get()));
     61     term_extractor_.reset(new PhishingTermFeatureExtractor(
     62         &scorer_->page_terms(),
     63         &scorer_->page_words(),
     64         scorer_->max_words_per_term(),
     65         scorer_->murmurhash3_seed(),
     66         clock_.get()));
     67   } else {
     68     // We're disabling client-side phishing detection, so tear down all
     69     // of the relevant objects.
     70     url_extractor_.reset();
     71     dom_extractor_.reset();
     72     term_extractor_.reset();
     73   }
     74 }
     75 
     76 bool PhishingClassifier::is_ready() const {
     77   return scorer_ != NULL;
     78 }
     79 
     80 void PhishingClassifier::BeginClassification(
     81     const base::string16* page_text,
     82     const DoneCallback& done_callback) {
     83   DCHECK(is_ready());
     84 
     85   // The RenderView should have called CancelPendingClassification() before
     86   // starting a new classification, so DCHECK this.
     87   CheckNoPendingClassification();
     88   // However, in an opt build, we will go ahead and clean up the pending
     89   // classification so that we can start in a known state.
     90   CancelPendingClassification();
     91 
     92   page_text_ = page_text;
     93   done_callback_ = done_callback;
     94 
     95   // For consistency, we always want to invoke the DoneCallback
     96   // asynchronously, rather than directly from this method.  To ensure that
     97   // this is the case, post a task to begin feature extraction on the next
     98   // iteration of the message loop.
     99   base::MessageLoop::current()->PostTask(
    100       FROM_HERE,
    101       base::Bind(&PhishingClassifier::BeginFeatureExtraction,
    102                  weak_factory_.GetWeakPtr()));
    103 }
    104 
    105 void PhishingClassifier::BeginFeatureExtraction() {
    106   blink::WebView* web_view = render_view_->GetWebView();
    107   if (!web_view) {
    108     RunFailureCallback();
    109     return;
    110   }
    111 
    112   blink::WebFrame* frame = web_view->mainFrame();
    113   if (!frame) {
    114     RunFailureCallback();
    115     return;
    116   }
    117 
    118   // Check whether the URL is one that we should classify.
    119   // Currently, we only classify http: URLs that are GET requests.
    120   GURL url(frame->document().url());
    121   if (!url.SchemeIs(content::kHttpScheme)) {
    122     RunFailureCallback();
    123     return;
    124   }
    125 
    126   blink::WebDataSource* ds = frame->dataSource();
    127   if (!ds || !EqualsASCII(ds->request().httpMethod(), "GET")) {
    128     RunFailureCallback();
    129     return;
    130   }
    131 
    132   features_.reset(new FeatureMap);
    133   if (!url_extractor_->ExtractFeatures(url, features_.get())) {
    134     RunFailureCallback();
    135     return;
    136   }
    137 
    138   // DOM feature extraction can take awhile, so it runs asynchronously
    139   // in several chunks of work and invokes the callback when finished.
    140   dom_extractor_->ExtractFeatures(
    141       features_.get(),
    142       base::Bind(&PhishingClassifier::DOMExtractionFinished,
    143                  base::Unretained(this)));
    144 }
    145 
    146 void PhishingClassifier::CancelPendingClassification() {
    147   // Note that cancelling the feature extractors is simply a no-op if they
    148   // were not running.
    149   DCHECK(is_ready());
    150   dom_extractor_->CancelPendingExtraction();
    151   term_extractor_->CancelPendingExtraction();
    152   weak_factory_.InvalidateWeakPtrs();
    153   Clear();
    154 }
    155 
    156 void PhishingClassifier::DOMExtractionFinished(bool success) {
    157   if (success) {
    158     // Term feature extraction can take awhile, so it runs asynchronously
    159     // in several chunks of work and invokes the callback when finished.
    160     term_extractor_->ExtractFeatures(
    161         page_text_,
    162         features_.get(),
    163         base::Bind(&PhishingClassifier::TermExtractionFinished,
    164                    base::Unretained(this)));
    165   } else {
    166     RunFailureCallback();
    167   }
    168 }
    169 
    170 void PhishingClassifier::TermExtractionFinished(bool success) {
    171   if (success) {
    172     blink::WebView* web_view = render_view_->GetWebView();
    173     if (!web_view) {
    174       RunFailureCallback();
    175       return;
    176     }
    177     blink::WebFrame* main_frame = web_view->mainFrame();
    178     if (!main_frame) {
    179       RunFailureCallback();
    180       return;
    181     }
    182 
    183     // Hash all of the features so that they match the model, then compute
    184     // the score.
    185     FeatureMap hashed_features;
    186     ClientPhishingRequest verdict;
    187     verdict.set_model_version(scorer_->model_version());
    188     verdict.set_url(main_frame->document().url().spec());
    189     for (base::hash_map<std::string, double>::const_iterator it =
    190              features_->features().begin();
    191          it != features_->features().end(); ++it) {
    192       VLOG(2) << "Feature: " << it->first << " = " << it->second;
    193       bool result = hashed_features.AddRealFeature(
    194           crypto::SHA256HashString(it->first), it->second);
    195       DCHECK(result);
    196       ClientPhishingRequest::Feature* feature = verdict.add_feature_map();
    197       feature->set_name(it->first);
    198       feature->set_value(it->second);
    199     }
    200     float score = static_cast<float>(scorer_->ComputeScore(hashed_features));
    201     verdict.set_client_score(score);
    202     verdict.set_is_phishing(score >= kPhishyThreshold);
    203     RunCallback(verdict);
    204   } else {
    205     RunFailureCallback();
    206   }
    207 }
    208 
    209 void PhishingClassifier::CheckNoPendingClassification() {
    210   DCHECK(done_callback_.is_null());
    211   DCHECK(!page_text_);
    212   if (!done_callback_.is_null() || page_text_) {
    213     LOG(ERROR) << "Classification in progress, missing call to "
    214                << "CancelPendingClassification";
    215     UMA_HISTOGRAM_COUNTS("SBClientPhishing.CheckNoPendingClassificationFailed",
    216                          1);
    217   }
    218 }
    219 
    220 void PhishingClassifier::RunCallback(const ClientPhishingRequest& verdict) {
    221   done_callback_.Run(verdict);
    222   Clear();
    223 }
    224 
    225 void PhishingClassifier::RunFailureCallback() {
    226   ClientPhishingRequest verdict;
    227   // In this case we're not guaranteed to have a valid URL.  Just set it
    228   // to the empty string to make sure we have a valid protocol buffer.
    229   verdict.set_url("");
    230   verdict.set_client_score(kInvalidScore);
    231   verdict.set_is_phishing(false);
    232   RunCallback(verdict);
    233 }
    234 
    235 void PhishingClassifier::Clear() {
    236   page_text_ = NULL;
    237   done_callback_.Reset();
    238   features_.reset(NULL);
    239 }
    240 
    241 }  // namespace safe_browsing
    242