[Patch 5 of 6] Split out the site_isolation_policy files

content/common/cross_site_document_classifier.cc

Index: content/common/cross_site_document_classifier.cc
diff --git a/content/child/site_isolation_policy.cc b/content/common/cross_site_document_classifier.cc
similarity index 48%
rename from content/child/site_isolation_policy.cc
rename to content/common/cross_site_document_classifier.cc
index 0f9fc61ff26f93dd0be8b1c4f1587218d6d0273c..4edef53a47ab97eb2bdefb7987abf41e39f24415 100644
--- a/content/child/site_isolation_policy.cc
+++ b/content/common/cross_site_document_classifier.cc
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "content/child/site_isolation_policy.h"
+#include "content/common/cross_site_document_classifier.h"
 
 #include "base/basictypes.h"
 #include "base/command_line.h"
@@ -21,10 +21,6 @@ namespace content {
 
 namespace {
 
-// The gathering of UMA stats for site isolation is deactivated by default, and
-// only activated in renderer processes.
-static bool g_stats_gathering_enabled = false;
-
 // MIME types
 const char kTextHtml[] = "text/html";
 const char kTextXml[] = "text/xml";
@@ -35,20 +31,6 @@ const char kTextJson[] = "text/json";
 const char kTextXjson[] = "text/x-json";
 const char kTextPlain[] = "text/plain";
 
-// TODO(dsjang): this is only needed for collecting UMA stat. Will be deleted
-// when this class is used for actual blocking.
-bool IsRenderableStatusCode(int status_code) {
-  // Chrome only uses the content of a response with one of these status codes
-  // for CSS/JavaScript. For images, Chrome just ignores status code.
-  const int renderable_status_code[] = {
-      200, 201, 202, 203, 206, 300, 301, 302, 303, 305, 306, 307};
-  for (size_t i = 0; i < arraysize(renderable_status_code); ++i) {
-    if (renderable_status_code[i] == status_code)
-      return true;
-  }
-  return false;
-}
-
 bool MatchesSignature(StringPiece data,
                       const StringPiece signatures[],
                       size_t arr_size) {
@@ -73,223 +55,8 @@ bool MatchesSignature(StringPiece data,
   return false;
 }
 
-void IncrementHistogramCount(const std::string& name) {
-  // The default value of min, max, bucket_count are copied from histogram.h.
-  base::HistogramBase* histogram_pointer = base::Histogram::FactoryGet(
-      name, 1, 100000, 50, base::HistogramBase::kUmaTargetedHistogramFlag);
-  histogram_pointer->Add(1);
-}
-
-void IncrementHistogramEnum(const std::string& name,
-                            uint32 sample,
-                            uint32 boundary_value) {
-  // The default value of min, max, bucket_count are copied from histogram.h.
-  base::HistogramBase* histogram_pointer = base::LinearHistogram::FactoryGet(
-      name, 1, boundary_value, boundary_value + 1,
-      base::HistogramBase::kUmaTargetedHistogramFlag);
-  histogram_pointer->Add(sample);
-}
-
-void HistogramCountBlockedResponse(
-    const std::string& bucket_prefix,
-    const linked_ptr<SiteIsolationResponseMetaData>& resp_data,
-    bool nosniff_block) {
-  std::string block_label(nosniff_block ? ".NoSniffBlocked" : ".Blocked");
-  IncrementHistogramCount(bucket_prefix + block_label);
-
-  // The content is blocked if it is sniffed as HTML/JSON/XML. When
-  // the blocked response is with an error status code, it is not
-  // disruptive for the following reasons : 1) the blocked content is
-  // not a binary object (such as an image) since it is sniffed as
-  // text; 2) then, this blocking only breaks the renderer behavior
-  // only if it is either JavaScript or CSS. However, the renderer
-  // doesn't use the contents of JS/CSS with unaffected status code
-  // (e.g, 404). 3) the renderer is expected not to use the cross-site
-  // document content for purposes other than JS/CSS (e.g, XHR).
-  bool renderable_status_code =
-      IsRenderableStatusCode(resp_data->http_status_code);
-
-  if (renderable_status_code) {
-    IncrementHistogramEnum(
-        bucket_prefix + block_label + ".RenderableStatusCode",
-        resp_data->resource_type, RESOURCE_TYPE_LAST_TYPE);
-  } else {
-    IncrementHistogramCount(bucket_prefix + block_label +
-                            ".NonRenderableStatusCode");
-  }
-}
-
-void HistogramCountNotBlockedResponse(const std::string& bucket_prefix,
-                                      bool sniffed_as_js) {
-  IncrementHistogramCount(bucket_prefix + ".NotBlocked");
-  if (sniffed_as_js)
-    IncrementHistogramCount(bucket_prefix + ".NotBlocked.MaybeJS");
-}
-
 }  // namespace
 
-SiteIsolationResponseMetaData::SiteIsolationResponseMetaData() {
-}
-
-void SiteIsolationStatsGatherer::SetEnabled(bool enabled) {
-  g_stats_gathering_enabled = enabled;
-}
-
-linked_ptr<SiteIsolationResponseMetaData>
-SiteIsolationStatsGatherer::OnReceivedResponse(
-    const GURL& frame_origin,
-    const GURL& response_url,
-    ResourceType resource_type,
-    int origin_pid,
-    const ResourceResponseInfo& info) {
-  if (!g_stats_gathering_enabled)
-    return linked_ptr<SiteIsolationResponseMetaData>();
-
-  // if |origin_pid| is non-zero, it means that this response is for a plugin
-  // spawned from this renderer process. We exclude responses for plugins for
-  // now, but eventually, we're going to make plugin processes directly talk to
-  // the browser process so that we don't apply cross-site document blocking to
-  // them.
-  if (origin_pid)
-    return linked_ptr<SiteIsolationResponseMetaData>();
-
-  UMA_HISTOGRAM_COUNTS("SiteIsolation.AllResponses", 1);
-
-  // See if this is for navigation. If it is, don't block it, under the
-  // assumption that we will put it in an appropriate process.
-  if (IsResourceTypeFrame(resource_type))
-    return linked_ptr<SiteIsolationResponseMetaData>();
-
-  if (!CrossSiteDocumentClassifier::IsBlockableScheme(response_url))
-    return linked_ptr<SiteIsolationResponseMetaData>();
-
-  if (CrossSiteDocumentClassifier::IsSameSite(frame_origin, response_url))
-    return linked_ptr<SiteIsolationResponseMetaData>();
-
-  CrossSiteDocumentMimeType canonical_mime_type =
-      CrossSiteDocumentClassifier::GetCanonicalMimeType(info.mime_type);
-
-  if (canonical_mime_type == CROSS_SITE_DOCUMENT_MIME_TYPE_OTHERS)
-    return linked_ptr<SiteIsolationResponseMetaData>();
-
-  // Every CORS request should have the Access-Control-Allow-Origin header even
-  // if it is preceded by a pre-flight request. Therefore, if this is a CORS
-  // request, it has this header.  response.httpHeaderField() internally uses
-  // case-insensitive matching for the header name.
-  std::string access_control_origin;
-
-  // We can use a case-insensitive header name for EnumerateHeader().
-  info.headers->EnumerateHeader(NULL, "access-control-allow-origin",
-                                &access_control_origin);
-  if (CrossSiteDocumentClassifier::IsValidCorsHeaderSet(
-          frame_origin, response_url, access_control_origin))
-    return linked_ptr<SiteIsolationResponseMetaData>();
-
-  // Real XSD data collection starts from here.
-  std::string no_sniff;
-  info.headers->EnumerateHeader(NULL, "x-content-type-options", &no_sniff);
-
-  linked_ptr<SiteIsolationResponseMetaData> resp_data(
-      new SiteIsolationResponseMetaData);
-  resp_data->frame_origin = frame_origin.spec();
-  resp_data->response_url = response_url;
-  resp_data->resource_type = resource_type;
-  resp_data->canonical_mime_type = canonical_mime_type;
-  resp_data->http_status_code = info.headers->response_code();
-  resp_data->no_sniff = LowerCaseEqualsASCII(no_sniff, "nosniff");
-
-  return resp_data;
-}
-
-bool SiteIsolationStatsGatherer::OnReceivedFirstChunk(
-    const linked_ptr<SiteIsolationResponseMetaData>& resp_data,
-    const char* raw_data,
-    int raw_length) {
-  if (!g_stats_gathering_enabled)
-    return false;
-
-  DCHECK(resp_data.get());
-
-  StringPiece data(raw_data, raw_length);
-
-  // Record the length of the first received chunk of data to see if it's enough
-  // for sniffing.
-  UMA_HISTOGRAM_COUNTS("SiteIsolation.XSD.DataLength", raw_length);
-
-  // Record the number of cross-site document responses with a specific mime
-  // type (text/html, text/xml, etc).
-  UMA_HISTOGRAM_ENUMERATION("SiteIsolation.XSD.MimeType",
-                            resp_data->canonical_mime_type,
-                            CROSS_SITE_DOCUMENT_MIME_TYPE_MAX);
-
-  // Store the result of cross-site document blocking analysis.
-  bool would_block = false;
-  bool sniffed_as_js = SniffForJS(data);
-
-  // Record the number of responses whose content is sniffed for what its mime
-  // type claims it to be. For example, we apply a HTML sniffer for a document
-  // tagged with text/html here. Whenever this check becomes true, we'll block
-  // the response.
-  if (resp_data->canonical_mime_type != CROSS_SITE_DOCUMENT_MIME_TYPE_PLAIN) {
-    std::string bucket_prefix;
-    bool sniffed_as_target_document = false;
-    if (resp_data->canonical_mime_type == CROSS_SITE_DOCUMENT_MIME_TYPE_HTML) {
-      bucket_prefix = "SiteIsolation.XSD.HTML";
-      sniffed_as_target_document =
-          CrossSiteDocumentClassifier::SniffForHTML(data);
-    } else if (resp_data->canonical_mime_type ==
-               CROSS_SITE_DOCUMENT_MIME_TYPE_XML) {
-      bucket_prefix = "SiteIsolation.XSD.XML";
-      sniffed_as_target_document =
-          CrossSiteDocumentClassifier::SniffForXML(data);
-    } else if (resp_data->canonical_mime_type ==
-               CROSS_SITE_DOCUMENT_MIME_TYPE_JSON) {
-      bucket_prefix = "SiteIsolation.XSD.JSON";
-      sniffed_as_target_document =
-          CrossSiteDocumentClassifier::SniffForJSON(data);
-    } else {
-      NOTREACHED() << "Not a blockable mime type: "
-                   << resp_data->canonical_mime_type;
-    }
-
-    if (sniffed_as_target_document) {
-      would_block = true;
-      HistogramCountBlockedResponse(bucket_prefix, resp_data, false);
-    } else {
-      if (resp_data->no_sniff) {
-        would_block = true;
-        HistogramCountBlockedResponse(bucket_prefix, resp_data, true);
-      } else {
-        HistogramCountNotBlockedResponse(bucket_prefix, sniffed_as_js);
-      }
-    }
-  } else {
-    // This block is for plain text documents. We apply our HTML, XML,
-    // and JSON sniffer to a text document in the order, and block it
-    // if any of them succeeds in sniffing.
-    std::string bucket_prefix;
-    if (CrossSiteDocumentClassifier::SniffForHTML(data))
-      bucket_prefix = "SiteIsolation.XSD.Plain.HTML";
-    else if (CrossSiteDocumentClassifier::SniffForXML(data))
-      bucket_prefix = "SiteIsolation.XSD.Plain.XML";
-    else if (CrossSiteDocumentClassifier::SniffForJSON(data))
-      bucket_prefix = "SiteIsolation.XSD.Plain.JSON";
-
-    if (bucket_prefix.size() > 0) {
-      would_block = true;
-      HistogramCountBlockedResponse(bucket_prefix, resp_data, false);
-    } else if (resp_data->no_sniff) {
-      would_block = true;
-      HistogramCountBlockedResponse("SiteIsolation.XSD.Plain", resp_data, true);
-    } else {
-      HistogramCountNotBlockedResponse("SiteIsolation.XSD.Plain",
-                                       sniffed_as_js);
-    }
-  }
-
-  return would_block;
-}
-
 CrossSiteDocumentMimeType CrossSiteDocumentClassifier::GetCanonicalMimeType(
     const std::string& mime_type) {
   if (LowerCaseEqualsASCII(mime_type, kTextHtml)) {
@@ -483,11 +250,4 @@ bool CrossSiteDocumentClassifier::SniffForJSON(base::StringPiece data) {
   return state == kColonState;
 }
 
-bool SiteIsolationStatsGatherer::SniffForJS(StringPiece data) {
-  // The purpose of this function is to try to see if there's any possibility
-  // that this data can be JavaScript (superset of JS). Search for "var " for JS
-  // detection. This is a real hack and should only be used for stats gathering.
-  return data.find("var ") != base::StringPiece::npos;
-}
-
 }  // namespace content