2 files changed, 318 insertions, 0 deletions
diff --git a/browser/extensions/webcompat/experiment-apis/trackingProtection.js b/browser/extensions/webcompat/experiment-apis/trackingProtection.js
new file mode 100644
index 0000000000..0f5d9a4233
--- /dev/null
+++ b/browser/extensions/webcompat/experiment-apis/trackingProtection.js
@@ -0,0 +1,216 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * 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/. */
+
+"use strict";
+
+/* global ExtensionAPI, ExtensionCommon, ExtensionParent, Services, XPCOMUtils */
+
+// eslint-disable-next-line mozilla/reject-importGlobalProperties
+XPCOMUtils.defineLazyGlobalGetters(this, ["URL", "ChannelWrapper"]);
+
+class AllowList {
+  constructor(id) {
+    this._id = id;
+  }
+
+  setShims(patterns, notHosts) {
+    this._shimPatterns = patterns;
+    this._shimMatcher = new MatchPatternSet(patterns || []);
+    this._shimNotHosts = notHosts || [];
+    return this;
+  }
+
+  setAllows(patterns, hosts) {
+    this._allowPatterns = patterns;
+    this._allowMatcher = new MatchPatternSet(patterns || []);
+    this._allowHosts = hosts || [];
+    return this;
+  }
+
+  shims(url, topHost) {
+    return (
+      this._shimMatcher?.matches(url) && !this._shimNotHosts?.includes(topHost)
+    );
+  }
+
+  allows(url, topHost) {
+    return (
+      this._allowMatcher?.matches(url) && this._allowHosts?.includes(topHost)
+    );
+  }
+}
+
+class Manager {
+  constructor() {
+    this._allowLists = new Map();
+  }
+
+  _getAllowList(id) {
+    if (!this._allowLists.has(id)) {
+      this._allowLists.set(id, new AllowList(id));
+    }
+    return this._allowLists.get(id);
+  }
+
+  _ensureStarted() {
+    if (this._classifierObserver) {
+      return;
+    }
+
+    this._unblockedChannelIds = new Set();
+    this._channelClassifier = Cc[
+      "@mozilla.org/url-classifier/channel-classifier-service;1"
+    ].getService(Ci.nsIChannelClassifierService);
+    this._classifierObserver = {};
+    this._classifierObserver.observe = (subject, topic, data) => {
+      switch (topic) {
+        case "http-on-stop-request": {
+          const { channelId } = subject.QueryInterface(Ci.nsIIdentChannel);
+          this._unblockedChannelIds.delete(channelId);
+          break;
+        }
+        case "urlclassifier-before-block-channel": {
+          const channel = subject.QueryInterface(
+            Ci.nsIUrlClassifierBlockedChannel
+          );
+          const { channelId, url } = channel;
+          let topHost;
+          try {
+            topHost = new URL(channel.topLevelUrl).hostname;
+          } catch (_) {
+            return;
+          }
+          // If anti-tracking webcompat is disabled, we only permit replacing
+          // channels, not fully unblocking them.
+          if (Manager.ENABLE_WEBCOMPAT) {
+            // if any allowlist unblocks the request entirely, we allow it
+            for (const allowList of this._allowLists.values()) {
+              if (allowList.allows(url, topHost)) {
+                this._unblockedChannelIds.add(channelId);
+                channel.allow();
+                return;
+              }
+            }
+          }
+          // otherwise, if any allowlist shims the request we say it's replaced
+          for (const allowList of this._allowLists.values()) {
+            if (allowList.shims(url, topHost)) {
+              this._unblockedChannelIds.add(channelId);
+              channel.replace();
+              return;
+            }
+          }
+          break;
+        }
+      }
+    };
+    Services.obs.addObserver(this._classifierObserver, "http-on-stop-request");
+    this._channelClassifier.addListener(this._classifierObserver);
+  }
+
+  stop() {
+    if (!this._classifierObserver) {
+      return;
+    }
+
+    Services.obs.removeObserver(
+      this._classifierObserver,
+      "http-on-stop-request"
+    );
+    this._channelClassifier.removeListener(this._classifierObserver);
+    delete this._channelClassifier;
+    delete this._classifierObserver;
+  }
+
+  wasChannelIdUnblocked(channelId) {
+    return this._unblockedChannelIds?.has(channelId);
+  }
+
+  allow(allowListId, patterns, hosts) {
+    this._ensureStarted();
+    this._getAllowList(allowListId).setAllows(patterns, hosts);
+  }
+
+  shim(allowListId, patterns, notHosts) {
+    this._ensureStarted();
+    this._getAllowList(allowListId).setShims(patterns, notHosts);
+  }
+
+  revoke(allowListId) {
+    this._allowLists.delete(allowListId);
+  }
+}
+var manager = new Manager();
+
+function getChannelId(context, requestId) {
+  const wrapper = ChannelWrapper.getRegisteredChannel(
+    requestId,
+    context.extension.policy,
+    context.xulBrowser.frameLoader.remoteTab
+  );
+  return wrapper?.channel?.QueryInterface(Ci.nsIIdentChannel)?.channelId;
+}
+
+var dFPIPrefName = "network.cookie.cookieBehavior";
+var dFPIPbPrefName = "network.cookie.cookieBehavior.pbmode";
+var dFPIStatus;
+function updateDFPIStatus() {
+  dFPIStatus = {
+    nonPbMode: 5 == Services.prefs.getIntPref(dFPIPrefName),
+    pbMode: 5 == Services.prefs.getIntPref(dFPIPbPrefName),
+  };
+}
+
+this.trackingProtection = class extends ExtensionAPI {
+  onShutdown(isAppShutdown) {
+    if (manager) {
+      manager.stop();
+    }
+    Services.prefs.removeObserver(dFPIPrefName, updateDFPIStatus);
+    Services.prefs.removeObserver(dFPIPbPrefName, updateDFPIStatus);
+  }
+
+  getAPI(context) {
+    Services.prefs.addObserver(dFPIPrefName, updateDFPIStatus);
+    Services.prefs.addObserver(dFPIPbPrefName, updateDFPIStatus);
+    updateDFPIStatus();
+
+    return {
+      trackingProtection: {
+        async shim(allowListId, patterns, notHosts) {
+          manager.shim(allowListId, patterns, notHosts);
+        },
+        async allow(allowListId, patterns, hosts) {
+          manager.allow(allowListId, patterns, hosts);
+        },
+        async revoke(allowListId) {
+          manager.revoke(allowListId);
+        },
+        async wasRequestUnblocked(requestId) {
+          if (!manager) {
+            return false;
+          }
+          const channelId = getChannelId(context, requestId);
+          if (!channelId) {
+            return false;
+          }
+          return manager.wasChannelIdUnblocked(channelId);
+        },
+        async isDFPIActive(isPrivate) {
+          if (isPrivate) {
+            return dFPIStatus.pbMode;
+          }
+          return dFPIStatus.nonPbMode;
+        },
+      },
+    };
+  }
+};
+
+XPCOMUtils.defineLazyPreferenceGetter(
+  Manager,
+  "ENABLE_WEBCOMPAT",
+  "privacy.antitracking.enableWebcompat",
+  false
+);
diff --git a/browser/extensions/webcompat/experiment-apis/trackingProtection.json b/browser/extensions/webcompat/experiment-apis/trackingProtection.json
new file mode 100644
index 0000000000..c495f39add
--- /dev/null
+++ b/browser/extensions/webcompat/experiment-apis/trackingProtection.json
@@ -0,0 +1,102 @@
+[
+  {
+    "namespace": "trackingProtection",
+    "description": "experimental API allow requests through ETP",
+    "functions": [
+      {
+        "name": "isDFPIActive",
+        "type": "function",
+        "description": "Returns whether dFPI is active for private/non-private browsing tabs",
+        "parameters": [
+          {
+            "type": "boolean",
+            "name": "isPrivate"
+          }
+        ],
+        "async": true
+      },
+      {
+        "name": "shim",
+        "type": "function",
+        "description": "Set specified URL patterns as intended to be shimmed",
+        "parameters": [
+          {
+            "name": "allowlistId",
+            "description": "Identfier for the allow-list, so it may be added-to or revoked",
+            "type": "string"
+          },
+          {
+            "name": "patterns",
+            "description": "Array of match patterns",
+            "type": "array",
+            "items": {
+              "type": "string"
+            }
+          },
+          {
+            "name": "notHosts",
+            "description": "Hosts on which to not shim these patterns",
+            "type": "array",
+            "optional": true,
+            "items": {
+              "type": "string"
+            }
+          }
+        ]
+      },
+      {
+        "name": "allow",
+        "type": "function",
+        "description": "Set specified URL patterns as intended to be allowed through the content blocker for the specified top hosts",
+        "parameters": [
+          {
+            "name": "allowlistId",
+            "description": "Identfier for the allow-list, so it may be added-to or revoked",
+            "type": "string"
+          },
+          {
+            "name": "patterns",
+            "description": "Array of match patterns",
+            "type": "array",
+            "items": {
+              "type": "string"
+            }
+          },
+          {
+            "name": "hosts",
+            "description": "Hosts to allow the patterns on",
+            "type": "array",
+            "items": {
+              "type": "string"
+            }
+          }
+        ],
+        "async": true
+      },
+      {
+        "name": "revoke",
+        "type": "function",
+        "description": "Revokes the given allow-list entirely (both shims and allows)",
+        "parameters": [
+          {
+            "name": "allowListId",
+            "type": "string"
+          }
+        ],
+        "async": true
+      },
+      {
+        "name": "wasRequestUnblocked",
+        "type": "function",
+        "description": "Whether the given requestId was unblocked by any allowList",
+        "parameters": [
+          {
+            "name": "requestId",
+            "type": "string"
+          }
+        ],
+        "async": true
+      }
+    ]
+  }
+]