Bug 1531405 - Gather telemetry on cross-origin style sheet Content-Type headers r=JuniorHsu

Differential Revision: https://phabricator.services.mozilla.com/D47906

--HG--
extra : moz-landing-system : lando

netwerk/protocol/http/nsHttpChannel.cpp

@@ -1767,6 +1767,8 @@ nsresult nsHttpChannel::CallOnStartRequest() {
     return mStatus;
   }
 
+  ReportContentTypeTelemetryForCrossOriginStylesheets();
+
   mTracingEnabled = false;
 
   // Ensure mListener->OnStartRequest will be invoked before exiting
@@ -8074,6 +8076,88 @@ nsresult nsHttpChannel::ContinueOnStopRequestAfterAuthRetry(
   return ContinueOnStopRequest(aStatus, aIsFromNet, aContentComplete);
 }
 
+class HeaderValuesVisitor final : public nsIHttpHeaderVisitor {
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIHTTPHEADERVISITOR
+
+  nsTArray<nsCString>& Get() { return mHeaderValues; }
+
+ private:
+  nsTArray<nsCString> mHeaderValues;
+  ~HeaderValuesVisitor() = default;
+};
+
+NS_IMETHODIMP HeaderValuesVisitor::VisitHeader(const nsACString& aHeader,
+                                               const nsACString& aValue) {
+  mHeaderValues.AppendElement(aValue);
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(HeaderValuesVisitor, nsIHttpHeaderVisitor)
+
+void nsHttpChannel::ReportContentTypeTelemetryForCrossOriginStylesheets() {
+  // Only record for successful requests.
+  if (NS_FAILED(mStatus)) {
+    return;
+  }
+  // Only record for stylesheet requests
+  if (!mContentTypeHint.EqualsLiteral("text/css") &&
+      mLoadInfo->GetExternalContentPolicyType() !=
+          nsIContentPolicy::TYPE_STYLESHEET) {
+    return;
+  }
+
+  nsCOMPtr<nsIURI> docURI = mLoadInfo->LoadingPrincipal()->GetURI();
+  nsIScriptSecurityManager* ssm = nsContentUtils::GetSecurityManager();
+  bool isPrivateWin = mLoadInfo->GetOriginAttributes().mPrivateBrowsingId > 0;
+  nsresult rv = ssm->CheckSameOriginURI(mURI, docURI, false, isPrivateWin);
+  bool isSameOrigin = NS_SUCCEEDED(rv);
+
+  // Only report cross origin stylesheet requests
+  if (isSameOrigin) {
+    return;
+  }
+
+  RefPtr<HeaderValuesVisitor> visitor = new HeaderValuesVisitor();
+  rv = GetOriginalResponseHeader(NS_LITERAL_CSTRING("Content-Type"), visitor);
+
+  auto allEmptyValues = [&visitor]() {
+    for (const auto& v : visitor->Get()) {
+      if (!v.IsEmpty()) {
+        return false;
+      }
+    }
+    return true;
+  };
+
+  nsAutoCString contentType;
+  if (mResponseHead) {
+    mResponseHead->ContentType(contentType);
+  }
+
+  typedef Telemetry::LABELS_NETWORK_CROSS_ORIGIN_STYLESHEET_CONTENT_TYPE
+      CTLabels;
+  CTLabels label;
+  if (rv == NS_ERROR_NOT_AVAILABLE) {
+    // No Content-Type header
+    label = CTLabels::NoHeader;
+  } else if (allEmptyValues()) {
+    // Any/all Content-Type headers are empty
+    label = CTLabels::EmptyHeader;
+  } else if (contentType.IsEmpty()) {
+    // failed to parse
+    label = CTLabels::FailedToParse;
+  } else if (contentType.EqualsLiteral("text/css")) {
+    // text/css
+    label = CTLabels::ParsedTextCSS;
+  } else {
+    // some other value
+    label = CTLabels::ParsedOther;
+  }
+
+  Telemetry::AccumulateCategorical(label);
+}
+
 nsresult nsHttpChannel::ContinueOnStopRequest(nsresult aStatus, bool aIsFromNet,
                                               bool aContentComplete) {
   LOG(

netwerk/protocol/http/nsHttpChannel.h

@@ -504,6 +504,8 @@ class nsHttpChannel final : public HttpBaseChannel,
            rv == NS_ERROR_PORT_ACCESS_NOT_ALLOWED;
   }
 
+  void ReportContentTypeTelemetryForCrossOriginStylesheets();
+
   // Report net vs cache time telemetry
   void ReportNetVSCacheTelemetry();
   int64_t ComputeTelemetryBucketNumber(int64_t difftime_ms);

netwerk/test/unit/test_parse_content_type.js

@@ -4,6 +4,8 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+const { HttpServer } = ChromeUtils.import("resource://testing-common/httpd.js");
+
 var charset = {};
 var hadCharset = {};
 var type;
@@ -21,7 +23,7 @@ function check(aType, aCharset, aHadCharset) {
   reset();
 }
 
-function run_test() {
+add_task(function test_parseResponseContentType() {
   var netutil = Cc["@mozilla.org/network/util;1"].getService(Ci.nsINetUtil);
 
   type = netutil.parseRequestContentType("text/html", charset, hadCharset);
@@ -360,4 +362,156 @@ function run_test() {
     hadCharset
   );
   check("text/plain", "'UTF-8'", true);
+});
+
+function checkSnapshotValue(s, name, expectedValue) {
+  function telemetryCategoryIndex(name) {
+    let labels = [
+      "NoHeader",
+      "EmptyHeader",
+      "FailedToParse",
+      "ParsedTextCSS",
+      "ParsedOther",
+    ];
+    for (let i in labels) {
+      if (labels[i] == name) {
+        return i;
+      }
+    }
+    ok(false, "invalid category");
+    return;
+  }
+
+  if (!name) {
+    Assert.deepEqual(s.values, {}, "No probes should be recorded");
+    return;
+  }
+
+  let index = telemetryCategoryIndex(name);
+  equal(
+    s.values[index],
+    expectedValue,
+    `Checking the value of ${name} to be ${expectedValue} - recorded probes: ${JSON.stringify(
+      s.values
+    )} index: ${index}`
+  );
+
+  for (let i in s.values) {
+    if (i != index && s.values[i] != 0) {
+      equal(s.values[i], 0, `The record at ${i} should be 0`);
+    }
+  }
 }
+
+function makeChan(url, type = Ci.nsIContentPolicy.TYPE_STYLESHEET) {
+  let principal = Services.scriptSecurityManager.createContentPrincipal(
+    Services.io.newURI("http://example.com"),
+    {
+      privateBrowsingId: 0,
+    }
+  );
+
+  return NetUtil.newChannel({
+    uri: url,
+    loadingPrincipal: principal,
+    contentPolicyType: type,
+    securityFlags: Ci.nsILoadInfo.SEC_ALLOW_CROSS_ORIGIN_DATA_IS_NULL,
+  }).QueryInterface(Ci.nsIHttpChannel);
+}
+
+add_task(async function check_channels() {
+  do_get_profile();
+
+  let contentType = "text/css;hi";
+  let content = `.identity-color-blue {
+    --identity-tab-color: #37adff;
+    --identity-icon-color: #37adff;
+}`;
+
+  function handler(metadata, response) {
+    if (contentType !== undefined) {
+      response.setHeader("Content-Type", contentType);
+    }
+    response.bodyOutputStream.write(content, content.length);
+  }
+  let httpserv = new HttpServer();
+  httpserv.registerPathHandler("/", handler);
+  httpserv.start(-1);
+  const URL = `http://localhost:${httpserv.identity.primaryPort}/`;
+
+  let h = Services.telemetry.getHistogramById(
+    "NETWORK_CROSS_ORIGIN_STYLESHEET_CONTENT_TYPE"
+  );
+  h.clear();
+
+  function make_test(
+    inContentType,
+    expectedContentType,
+    expectedProbe,
+    typeHint,
+    contentPolicyType
+  ) {
+    return new Promise(resolve => {
+      contentType = inContentType;
+      let channel = makeChan(URL, contentPolicyType);
+      if (typeHint) {
+        channel.contentType = typeHint;
+      }
+      let p = new Promise(resolve1 =>
+        channel.asyncOpen(new ChannelListener(resolve1))
+      );
+      p.then(() => {
+        equal(channel.contentType, expectedContentType);
+        checkSnapshotValue(h.snapshot(), expectedProbe, 1);
+        h.clear();
+        resolve();
+      });
+    });
+  }
+
+  // If contentTypeHint != text/css and contentPolicy is not TYPE_STYLESHEET
+  // no telemetry probes should be recorded.
+  await make_test(
+    undefined,
+    "text/plain",
+    undefined,
+    undefined,
+    Ci.nsIContentPolicy.TYPE_OTHER
+  );
+  await make_test(
+    undefined,
+    "text/plain",
+    undefined,
+    "text/plain",
+    Ci.nsIContentPolicy.TYPE_OTHER
+  );
+
+  // We should record a probe if the contentTypeHint is text/css
+  await make_test(
+    undefined,
+    "text/css",
+    "NoHeader",
+    "text/css",
+    Ci.nsIContentPolicy.TYPE_OTHER
+  );
+
+  // The rest of the tests will default to contentPolicy = TYPE_STYLESHEET
+  // One telemetry probe should be recorded for each.
+  await make_test(undefined, "text/plain", "NoHeader");
+  await make_test(undefined, "text/abc", "NoHeader", "text/abc");
+  await make_test(undefined, "text/css", "NoHeader", "text/css");
+  await make_test("", "text/plain", "EmptyHeader");
+  await make_test("", "text/abc", "EmptyHeader", "text/abc");
+  await make_test("", "text/css", "EmptyHeader", "text/css");
+  await make_test("failure", "text/plain", "FailedToParse");
+  await make_test("failure", "text/abc", "FailedToParse", "text/abc");
+  await make_test("failure", "text/css", "FailedToParse", "text/css");
+  await make_test("text/css", "text/css", "ParsedTextCSS");
+  await make_test("text/css;hi", "text/css", "ParsedTextCSS");
+  await make_test("text/plain", "text/plain", "ParsedOther");
+  await make_test("text/abc", "text/abc", "ParsedOther");
+  await make_test("text/abc;hi", "text/abc", "ParsedOther");
+  await make_test("text/abc", "text/abc", "ParsedOther", "text/css");
+
+  await new Promise(resolve => httpserv.stop(resolve));
+});

toolkit/components/telemetry/Histograms.json

@@ -2486,6 +2486,17 @@
     "description": "Count of the HTTP redirection that triggered by top-level document or by subresource, keyed by the URL scheme redirected to.",
     "labels": ["topLevel", "subresource"]
   },
+  "NETWORK_CROSS_ORIGIN_STYLESHEET_CONTENT_TYPE": {
+    "record_in_processes": ["main"],
+    "products": ["firefox", "fennec", "geckoview"],
+    "alert_emails": ["necko@mozilla.com", "vgosu@mozilla.com"],
+    "bug_numbers": [1531405],
+    "expires_in_version": "75",
+    "releaseChannelCollection": "opt-out",
+    "kind": "categorical",
+    "description": "Records whether a Content-Type header was present when loading a cross origin stylesheet, and if it was parsed successfully.",
+    "labels": ["NoHeader", "EmptyHeader", "FailedToParse", "ParsedTextCSS", "ParsedOther"]
+  },
   "HTTP_AUTH_DIALOG_STATS_3": {
     "record_in_processes": ["main", "content"],
     "products": ["firefox", "fennec", "geckoview"],