Bug 1720869 - Part 1: Add a telemetry probe for referrer policy. r=ckerschb,necko-reviewers,valentin

Differential Revision: https://phabricator.services.mozilla.com/D121344

dom/security/ReferrerInfo.cpp

@@ -27,6 +27,7 @@
 #include "mozilla/dom/Element.h"
 #include "mozilla/StaticPrefs_network.h"
 #include "mozilla/StyleSheet.h"
+#include "mozilla/Telemetry.h"
 #include "nsIWebProgressListener.h"
 
 static mozilla::LazyLogModule gReferrerInfoLog("ReferrerInfo");
@@ -506,6 +507,36 @@ bool ReferrerInfo::IsCrossOriginRequest(nsIHttpChannel* aChannel) {
   return !isSameOrigin;
 }
 
+/* static */
+bool ReferrerInfo::IsCrossSiteRequest(nsIHttpChannel* aChannel) {
+  nsCOMPtr<nsILoadInfo> loadInfo = aChannel->LoadInfo();
+
+  if (!loadInfo->TriggeringPrincipal()->GetIsContentPrincipal()) {
+    LOG(("no triggering URI via loadInfo, assuming load is cross-site"));
+    return true;
+  }
+
+  if (LOG_ENABLED()) {
+    nsAutoCString triggeringURISpec;
+    loadInfo->TriggeringPrincipal()->GetAsciiSpec(triggeringURISpec);
+    LOG(("triggeringURI=%s\n", triggeringURISpec.get()));
+  }
+
+  nsCOMPtr<nsIURI> uri;
+  nsresult rv = aChannel->GetURI(getter_AddRefs(uri));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return true;
+  }
+
+  bool isCrossSite = true;
+  rv = loadInfo->TriggeringPrincipal()->IsThirdPartyURI(uri, &isCrossSite);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return true;
+  }
+
+  return isCrossSite;
+}
+
 ReferrerInfo::TrimmingPolicy ReferrerInfo::ComputeTrimmingPolicy(
     nsIHttpChannel* aChannel) const {
   uint32_t trimmingPolicy = GetUserTrimmingPolicy();
@@ -689,24 +720,7 @@ bool ReferrerInfo::ShouldIgnoreLessRestrictedPolicies(
     return false;
   }
 
-  if (!loadInfo->TriggeringPrincipal()->GetIsContentPrincipal()) {
-    LOG(("no triggering URI via loadInfo, assuming load is cross-site"));
-    return true;
-  }
-
-  nsCOMPtr<nsIURI> uri;
-  nsresult rv = aChannel->GetURI(getter_AddRefs(uri));
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    return true;
-  }
-
-  bool isCrossSite = true;
-  rv = loadInfo->TriggeringPrincipal()->IsThirdPartyURI(uri, &isCrossSite);
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    return true;
-  }
-
-  return isCrossSite;
+  return IsCrossSiteRequest(aChannel);
 }
 
 void ReferrerInfo::LogMessageToConsole(
@@ -1457,5 +1471,22 @@ ReferrerInfo::Write(nsIObjectOutputStream* aStream) {
   return NS_OK;
 }
 
+void ReferrerInfo::RecordTelemetry(nsIHttpChannel* aChannel) {
+#ifdef DEBUG
+  MOZ_ASSERT(!mTelemetryRecorded);
+  mTelemetryRecorded = true;
+#endif  // DEBUG
+
+  // The telemetry probe has 18 buckets. The first 9 buckets are for same-site
+  // requests and the rest 9 buckets are for cross-site requests.
+  uint32_t telemetryOffset =
+      IsCrossSiteRequest(aChannel)
+          ? static_cast<uint32_t>(ReferrerPolicy::EndGuard_)
+          : 0;
+
+  Telemetry::Accumulate(Telemetry::REFERRER_POLICY_COUNT,
+                        static_cast<uint32_t>(mPolicy) + telemetryOffset);
+}
+
 }  // namespace dom
 }  // namespace mozilla

dom/security/ReferrerInfo.h

@@ -89,6 +89,9 @@ class ReferrerInfo : public nsIReferrerInfo {
   already_AddRefed<ReferrerInfo> CloneWithNewOriginalReferrer(
       nsIURI* aOriginalReferrer) const;
 
+  // Record the telemetry for the referrer policy.
+  void RecordTelemetry(nsIHttpChannel* aChannel);
+
   /*
    * Helper function to create a new ReferrerInfo object from other. We will not
    * pass in any computed values and override referrer policy if needed
@@ -180,6 +183,11 @@ class ReferrerInfo : public nsIReferrerInfo {
    */
   static bool IsCrossOriginRequest(nsIHttpChannel* aChannel);
 
+  /**
+   * Returns true if the given channel is cross-site request.
+   */
+  static bool IsCrossSiteRequest(nsIHttpChannel* aChannel);
+
   /**
    * Returns true if the given channel is suppressed by Referrer-Policy header
    * and should set "null" to Origin header.
@@ -449,6 +457,12 @@ class ReferrerInfo : public nsIReferrerInfo {
 
   // Store a computed referrer for a given channel
   Maybe<nsCString> mComputedReferrer;
+
+#ifdef DEBUG
+  // Indicates if the telemetry has been recorded. This is used to make sure the
+  // telemetry will be only recored once.
+  bool mTelemetryRecorded = false;
+#endif  // DEBUG
 };
 
 }  // namespace dom

netwerk/protocol/http/HttpBaseChannel.cpp

@@ -1627,6 +1627,12 @@ nsresult HttpBaseChannel::SetReferrerInfoInternal(
     return NS_ERROR_NOT_INITIALIZED;
   }
 
+  if (aClone) {
+    // Record the telemetry once we set the referrer info to the channel
+    // successfully.
+    referrerInfo->RecordTelemetry(this);
+  }
+
   if (aCompute) {
     rv = referrerInfo->ComputeReferrer(this);
     if (NS_WARN_IF(NS_FAILED(rv))) {

toolkit/components/telemetry/Histograms.json

@@ -16194,6 +16194,17 @@
     "n_buckets": 56,
     "description": "How much time (in hours) passed between the current cookie purging activity and the one before that (cookie purging is run on 'daily idle')"
   },
+  "REFERRER_POLICY_COUNT" : {
+    "products": ["firefox"],
+    "record_in_processes": ["main"],
+    "alert_emails": ["tihuang@mozilla.com", "jhofmann@mozilla.com", "ckerschbaumer@mozilla.com", "seceng-telemetry@mozilla.com"],
+    "expires_in_version": "never",
+    "kind" : "enumerated",
+    "n_values": 18,
+    "bug_numbers": [1720869],
+    "description": "The counter of each referrer policy which has been computed for a referrer. The buckets (0-8) are for same-site requests and buckets (9-17) are for cross-site requests. Note that the index matches to the order in ReferrerPolicy.webidl",
+    "releaseChannelCollection": "opt-out"
+  },
   "APZ_ZOOM_ACTIVITY" : {
     "products": ["firefox"],
     "record_in_processes": ["content"],