From 15cacd9bfdb9c08def24e780d83bb8dd672c711f Mon Sep 17 00:00:00 2001
From: grizzlyuser <grizzlyuser@protonmail.com>
Date: Wed, 30 Dec 2020 17:20:39 +0200
Subject: [PATCH 01/13] Point to local omni.ja files, not remote server

Basically replace every occurrence of Remote Settings server domain name
with URIs that point to built-in local files within omni.ja.

Some links to json files may point to non-existing files, but that's OK
because it's better than leave them point to Remote Settings server.
If necessary, missing files can be added later.
---
 .../components/ASRouterAdmin/ASRouterAdmin.jsx            | 2 +-
 .../newtab/data/content/activity-stream.bundle.js         | 2 +-
 modules/libpref/init/all.js                               | 2 +-
 services/settings/Utils.jsm                               | 4 ++--
 .../periodic-updates/scripts/periodic_file_updates.sh     | 2 +-
 toolkit/components/search/SearchUtils.jsm                 | 8 ++++----
 toolkit/components/search/docs/DefaultSearchEngines.rst   | 2 +-
 .../components/search/docs/SearchEngineConfiguration.rst  | 2 +-
 toolkit/mozapps/defaultagent/RemoteSettings.cpp           | 2 +-
 9 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/browser/components/newtab/content-src/components/ASRouterAdmin/ASRouterAdmin.jsx b/browser/components/newtab/content-src/components/ASRouterAdmin/ASRouterAdmin.jsx
index e0d8e45cc0..4cb5fca1c6 100644
--- a/browser/components/newtab/content-src/components/ASRouterAdmin/ASRouterAdmin.jsx
+++ b/browser/components/newtab/content-src/components/ASRouterAdmin/ASRouterAdmin.jsx
@@ -1230,7 +1230,7 @@ export class ASRouterAdminInner extends React.PureComponent {
                   <a
                     className="providerUrl"
                     target="_blank"
-                    href="https://firefox.settings.services.mozilla.com/v1/buckets/main/collections/nimbus-desktop-experiments/records"
+                    href="resource://app/defaults/settings/main/nimbus-desktop-experiments.json"
                     rel="noopener noreferrer"
                   >
                     nimbus-desktop-experiments
diff --git a/browser/components/newtab/data/content/activity-stream.bundle.js b/browser/components/newtab/data/content/activity-stream.bundle.js
index 5227e5af81..427759dcfe 100644
--- a/browser/components/newtab/data/content/activity-stream.bundle.js
+++ b/browser/components/newtab/data/content/activity-stream.bundle.js
@@ -1841,7 +1841,7 @@ class ASRouterAdminInner extends react__WEBPACK_IMPORTED_MODULE_3___default.a.Pu
         label = /*#__PURE__*/react__WEBPACK_IMPORTED_MODULE_3___default.a.createElement("span", null, "remote settings (", /*#__PURE__*/react__WEBPACK_IMPORTED_MODULE_3___default.a.createElement("a", {
           className: "providerUrl",
           target: "_blank",
-          href: "https://firefox.settings.services.mozilla.com/v1/buckets/main/collections/nimbus-desktop-experiments/records",
+          href: "resource://app/defaults/settings/main/nimbus-desktop-experiments.json",
           rel: "noopener noreferrer"
         }, "nimbus-desktop-experiments"), ")");
       }
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index 1ed81b6f53..edca292681 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -2210,7 +2210,7 @@ pref("security.cert_pinning.hpkp.enabled", false);
 // Remote settings preferences
 // Note: if you change this, make sure to also review security.onecrl.maximum_staleness_in_seconds
 pref("services.settings.poll_interval", 86400); // 24H
-pref("services.settings.server", "https://firefox.settings.services.mozilla.com/v1");
+pref("services.settings.server", "resource://app/defaults/settings");
 pref("services.settings.default_bucket", "main");
 
 // The percentage of clients who will report uptake telemetry as
diff --git a/services/settings/Utils.jsm b/services/settings/Utils.jsm
index ee23591a6a..ef91781ac6 100644
--- a/services/settings/Utils.jsm
+++ b/services/settings/Utils.jsm
@@ -60,11 +60,11 @@ var Utils = {
     );
     const isXpcshell = env.exists("XPCSHELL_TEST_PROFILE_DIR");
     return AppConstants.RELEASE_OR_BETA && !Cu.isInAutomation && !isXpcshell
-      ? "https://firefox.settings.services.mozilla.com/v1"
+      ? "resource://app/defaults/settings"
       : gServerURL;
   },
 
-  CHANGES_PATH: "/buckets/monitor/collections/changes/changeset",
+  CHANGES_PATH: "/monitor/changes.json",
 
   /**
    * Logger instance.
diff --git a/taskcluster/docker/periodic-updates/scripts/periodic_file_updates.sh b/taskcluster/docker/periodic-updates/scripts/periodic_file_updates.sh
index 7764777c1a..3c8db49743 100755
--- a/taskcluster/docker/periodic-updates/scripts/periodic_file_updates.sh
+++ b/taskcluster/docker/periodic-updates/scripts/periodic_file_updates.sh
@@ -279,7 +279,7 @@ function compare_suffix_lists {
 }
 
 function compare_remote_settings_files {
-  REMOTE_SETTINGS_SERVER="https://firefox.settings.services.mozilla.com/v1"
+  REMOTE_SETTINGS_SERVER="resource://app/defaults/settings"
 
   # 1. List remote settings collections from server.
   echo "INFO: fetch remote settings list from server"
diff --git a/toolkit/components/search/SearchUtils.jsm b/toolkit/components/search/SearchUtils.jsm
index 8a3c6acb84..b0a9c4b86f 100644
--- a/toolkit/components/search/SearchUtils.jsm
+++ b/toolkit/components/search/SearchUtils.jsm
@@ -159,13 +159,13 @@ var SearchUtils = {
 
   ENGINES_URLS: {
     "prod-main":
-      "https://firefox.settings.services.mozilla.com/v1/buckets/main/collections/search-config/records",
+      "resource://app/defaults/settings/main/search-config.json",
     "prod-preview":
-      "https://firefox.settings.services.mozilla.com/v1/buckets/main-preview/collections/search-config/records",
+      "resource://app/defaults/settings/main/search-config.json",
     "stage-main":
-      "https://settings.stage.mozaws.net/v1/buckets/main/collections/search-config/records",
+      "resource://app/defaults/settings/main/search-config.json",
     "stage-preview":
-      "https://settings.stage.mozaws.net/v1/buckets/main-preview/collections/search-config/records",
+      "resource://app/defaults/settings/main/search-config.json",
   },
 
   // The following constants are left undocumented in nsISearchService.idl
diff --git a/toolkit/components/search/docs/DefaultSearchEngines.rst b/toolkit/components/search/docs/DefaultSearchEngines.rst
index 0648471396..37948dca31 100644
--- a/toolkit/components/search/docs/DefaultSearchEngines.rst
+++ b/toolkit/components/search/docs/DefaultSearchEngines.rst
@@ -86,4 +86,4 @@ is updated.
 
 .. _configuration schema: SearchConfigurationSchema.html
 .. _remote settings: /services/common/services/RemoteSettings.html
-.. _search-default-override-allowlist bucket: https://firefox.settings.services.mozilla.com/v1/buckets/main/collections/search-default-override-allowlist/records
+.. _search-default-override-allowlist bucket: resource://app/defaults/settings/main/search-default-override-allowlist.json
diff --git a/toolkit/components/search/docs/SearchEngineConfiguration.rst b/toolkit/components/search/docs/SearchEngineConfiguration.rst
index e9041affb8..7a9466d294 100644
--- a/toolkit/components/search/docs/SearchEngineConfiguration.rst
+++ b/toolkit/components/search/docs/SearchEngineConfiguration.rst
@@ -68,5 +68,5 @@ related. As a result several situations may occur:
 .. _JSON schema: https://json-schema.org/
 .. _stored in mozilla-central: https://searchfox.org/mozilla-central/source/toolkit/components/search/schema/
 .. _Search Configuration Schema: SearchConfigurationSchema.html
-.. _viewed live: https://firefox.settings.services.mozilla.com/v1/buckets/main/collections/search-config/records
+.. _viewed live: resource://app/defaults/settings/main/search-config.json
 .. _Normandy: /toolkit/components/normandy/normandy/services.html
diff --git a/toolkit/mozapps/defaultagent/RemoteSettings.cpp b/toolkit/mozapps/defaultagent/RemoteSettings.cpp
index 667d9fc628..b2bf628f29 100644
--- a/toolkit/mozapps/defaultagent/RemoteSettings.cpp
+++ b/toolkit/mozapps/defaultagent/RemoteSettings.cpp
@@ -23,7 +23,7 @@ extern "C" {
 HRESULT IsAgentRemoteDisabledRust(const char* szUrl, DWORD* lpdwDisabled);
 }
 
-#define PROD_ENDPOINT "https://firefox.settings.services.mozilla.com/v1"
+#define PROD_ENDPOINT "resource://app/defaults/settings"
 #define PROD_BID "main"
 #define PROD_CID "windows-default-browser-agent"
 #define PROD_ID "state"
-- 
2.31.1


From f1e92b5fb7844a57ad63d8a52b4867db9817fc14 Mon Sep 17 00:00:00 2001
From: grizzlyuser <grizzlyuser@protonmail.com>
Date: Wed, 30 Dec 2020 17:34:08 +0200
Subject: [PATCH 02/13] Remove polling triggered by push broadcasts

When initialized, remote-settings.js adds a listener to push broadcasts,
that let Remote Settings server send push messages to trigger polling
for changes from the client side. This is not needed for local-only
setup. Remove the record from broadcast-listeners.json file stored in
the user profile, so that it doesn't get picked up by push broadcast
service.
---
 dom/push/PushBroadcastService.jsm    | 13 +++++++++++++
 services/settings/remote-settings.js |  7 ++-----
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/dom/push/PushBroadcastService.jsm b/dom/push/PushBroadcastService.jsm
index aa1504211d..d635a2c3aa 100644
--- a/dom/push/PushBroadcastService.jsm
+++ b/dom/push/PushBroadcastService.jsm
@@ -178,6 +178,19 @@ var BroadcastService = class {
     }
   }
 
+  async deleteListener(broadcastId) {
+    await this.initializePromise;
+
+    if (this.jsonFile.data.listeners.hasOwnProperty(broadcastId)) {
+      console.info(
+        "deleteListener: deleting listener",
+        broadcastId
+      );
+      delete this.jsonFile.data.listeners[broadcastId];
+      this.jsonFile.saveSoon();
+    }
+  }
+
   /**
    * Call the listeners of the specified broadcasts.
    *
diff --git a/services/settings/remote-settings.js b/services/settings/remote-settings.js
index 6d0185faf9..aae93fa440 100644
--- a/services/settings/remote-settings.js
+++ b/services/settings/remote-settings.js
@@ -441,7 +441,7 @@ function remoteSettingsFunction() {
       moduleURI: __URI__,
       symbolName: "remoteSettingsBroadcastHandler",
     };
-    pushBroadcastService.addListener(BROADCAST_ID, currentVersion, moduleInfo);
+    pushBroadcastService.deleteListener(BROADCAST_ID);
   };
 
   return remoteSettings;
@@ -461,9 +461,6 @@ var remoteSettingsBroadcastHandler = {
       `Push notification received (version=${version} phase=${phase})`
     );
 
-    return RemoteSettings.pollChanges({
-      expectedTimestamp: version,
-      trigger: isStartup ? "startup" : "broadcast",
-    });
+    return;
   },
 };
-- 
2.31.1


From 3054d3efe22802ab5503dd812e0a0283bbd791f1 Mon Sep 17 00:00:00 2001
From: grizzlyuser <grizzlyuser@protonmail.com>
Date: Wed, 30 Dec 2020 17:41:54 +0200
Subject: [PATCH 03/13] Remove timer that triggers polling for changes

That is not needed for local-only setup.
---
 services/settings/components.conf           | 9 +--------
 services/settings/servicesSettings.manifest | 4 ----
 2 files changed, 1 insertion(+), 12 deletions(-)

diff --git a/services/settings/components.conf b/services/settings/components.conf
index 9a737802ee..25109415a7 100644
--- a/services/settings/components.conf
+++ b/services/settings/components.conf
@@ -4,11 +4,4 @@
 # 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/.
 
-Classes = [
-    {
-        'cid': '{5e756573-234a-49ea-bbe4-59ec7a70657d}',
-        'contract_ids': ['@mozilla.org/services/settings;1'],
-        'jsm': 'resource://services-settings/RemoteSettingsComponents.jsm',
-        'constructor': 'RemoteSettingsTimer',
-    },
-]
+Classes = []
diff --git a/services/settings/servicesSettings.manifest b/services/settings/servicesSettings.manifest
index 3bfed26ea4..807eb220ec 100644
--- a/services/settings/servicesSettings.manifest
+++ b/services/settings/servicesSettings.manifest
@@ -1,7 +1,3 @@
 # Register resource aliases
 resource services-settings resource://gre/modules/services-settings/
 
-# Schedule polling of remote settings changes
-# (default 24H, max 72H)
-# see syntax https://searchfox.org/mozilla-central/rev/cc280c4be94ff8cf64a27cc9b3d6831ffa49fa45/toolkit/components/timermanager/UpdateTimerManager.jsm#155
-category update-timer RemoteSettingsComponents @mozilla.org/services/settings;1,getService,services-settings-poll-changes,services.settings.poll_interval,86400,259200
-- 
2.31.1


From c856641861ca70da2d5aa720e402f2e505ebe5ac Mon Sep 17 00:00:00 2001
From: grizzlyuser <grizzlyuser@protonmail.com>
Date: Wed, 30 Dec 2020 17:47:41 +0200
Subject: [PATCH 04/13] Utils: fetch timestamps of each collection locally

Utils.CHANGES_PATH points to
services/settings/dumps/monitor/changes.json
which will be generated later by JSON processing script. Fetch the
timestamps from that file and mock response headers to not confuse any
code that expects them.
---
 browser/installer/package-manifest.in     |  1 +
 services/settings/Utils.jsm               | 13 ++++++++++++-
 services/settings/dumps/monitor/moz.build |  8 ++++++++
 services/settings/dumps/moz.build         |  1 +
 4 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 services/settings/dumps/monitor/moz.build

diff --git a/browser/installer/package-manifest.in b/browser/installer/package-manifest.in
index ec20499166..c618c02a8f 100644
--- a/browser/installer/package-manifest.in
+++ b/browser/installer/package-manifest.in
@@ -298,6 +298,7 @@
 @RESPATH@/browser/defaults/settings/blocklists
 @RESPATH@/browser/defaults/settings/pinning
 @RESPATH@/browser/defaults/settings/main
+@RESPATH@/browser/defaults/settings/monitor
 @RESPATH@/browser/defaults/settings/security-state
 
 ; Warning: changing the path to channel-prefs.js can cause bugs (Bug 756325)
diff --git a/services/settings/Utils.jsm b/services/settings/Utils.jsm
index ef91781ac6..8736951968 100644
--- a/services/settings/Utils.jsm
+++ b/services/settings/Utils.jsm
@@ -150,7 +150,7 @@ var Utils = {
   async fetchLatestChanges(serverUrl, options = {}) {
     const { expectedTimestamp, lastEtag = "", filters = {} } = options;
 
-    let url = serverUrl + Utils.CHANGES_PATH;
+    let url = Utils.SERVER_URL + Utils.CHANGES_PATH;
     const params = {
       ...filters,
       _expected: expectedTimestamp ?? 0,
@@ -166,6 +166,9 @@ var Utils = {
           .join("&");
     }
     const response = await fetch(url);
+    const responseDate = new Date().toUTCString()
+    response.headers.set("Date", responseDate);
+    response.headers.set("Last-Modified", responseDate);
 
     if (response.status >= 500) {
       throw new Error(`Server error ${response.status} ${response.statusText}`);
@@ -200,7 +194,15 @@ var Utils = {
       }
     }
 
-    const { changes = [], timestamp } = payload;
+    const { timestamp } = payload;
+    const { bucket, collection } = filters;
+    if (!bucket || !collection) {
+      throw new Error('Unable to fetch latest change without bucket or collection');
+    }
+    const change = payload.changes.find(
+        change => change.bucket === bucket && change.collection === collection
+      ) ?? { last_modified: 0, bucket, collection };
+    const changes = [change];
 
     let serverTimeMillis = Date.parse(response.headers.get("Date"));
     // Since the response is served via a CDN, the Date header value could have been cached.
diff --git a/services/settings/dumps/monitor/moz.build b/services/settings/dumps/monitor/moz.build
new file mode 100644
index 0000000000..d3d017fda5
--- /dev/null
+++ b/services/settings/dumps/monitor/moz.build
@@ -0,0 +1,8 @@
+# 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/.
+
+FINAL_TARGET_FILES.defaults.settings.monitor += ["changes.json"]
+
+if CONFIG["MOZ_BUILD_APP"] == "browser":
+    DIST_SUBDIR = "browser"
diff --git a/services/settings/dumps/moz.build b/services/settings/dumps/moz.build
index 3cc9436f61..3742da5667 100644
--- a/services/settings/dumps/moz.build
+++ b/services/settings/dumps/moz.build
@@ -5,6 +5,7 @@
 DIRS += [
     "blocklists",
     "main",
+    "monitor",
     "pinning",
     "security-state",
 ]
-- 
2.31.1


From a0f311bed359d484fbf85e696b5b7e3a288292f8 Mon Sep 17 00:00:00 2001
From: grizzlyuser <grizzlyuser@protonmail.com>
Date: Wed, 30 Dec 2020 17:52:10 +0200
Subject: [PATCH 05/13] Utils: disable offline checking

Since only local data is read now, it should always return false for the
current and any future code that relies on it.
---
 services/settings/Utils.jsm | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/services/settings/Utils.jsm b/services/settings/Utils.jsm
index 8736951968..8ac085feea 100644
--- a/services/settings/Utils.jsm
+++ b/services/settings/Utils.jsm
@@ -80,15 +80,6 @@ var Utils = {
    * @return {bool} Whether network is down or not.
    */
   get isOffline() {
-    try {
-      return (
-        Services.io.offline ||
-        CaptivePortalService.state == CaptivePortalService.LOCKED_PORTAL ||
-        !gNetworkLinkService.isLinkUp
-      );
-    } catch (ex) {
-      log.warn("Could not determine network status.", ex);
-    }
     return false;
   },
 
-- 
2.31.1


From 95e4979573c79c987160a71e913c7564de22127f Mon Sep 17 00:00:00 2001
From: grizzlyuser <grizzlyuser@protonmail.com>
Date: Wed, 30 Dec 2020 17:56:02 +0200
Subject: [PATCH 06/13] Refactor hashing logic to a separate function

It is used instead of internal signature validation mechanism, for
integrity checking of the locally cached data.
---
 services/settings/RemoteSettingsWorker.jsm | 4 ++++
 services/settings/SharedUtils.jsm          | 9 +++++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/services/settings/RemoteSettingsWorker.jsm b/services/settings/RemoteSettingsWorker.jsm
index 147ebb6b13..c86e218fd3 100644
--- a/services/settings/RemoteSettingsWorker.jsm
+++ b/services/settings/RemoteSettingsWorker.jsm
@@ -189,6 +189,10 @@ class Worker {
     // task on the current thread instead of the worker thread.
     return SharedUtils.checkContentHash(buffer, size, hash);
   }
+
+  async getContentHash(bytes) {
+    return SharedUtils.getContentHash(bytes);
+  }
 }
 
 // Now, first add a shutdown blocker. If that fails, we must have
diff --git a/services/settings/SharedUtils.jsm b/services/settings/SharedUtils.jsm
index db5017a742..1a8e83c2e8 100644
--- a/services/settings/SharedUtils.jsm
+++ b/services/settings/SharedUtils.jsm
@@ -28,11 +28,16 @@ var SharedUtils = {
       return false;
     }
     // Has expected content?
+    const hashStr = await this.getContentHash(bytes);
+    return hashStr == hash;
+  },
+
+  async getContentHash(bytes) {
     const hashBuffer = await crypto.subtle.digest("SHA-256", bytes);
     const hashBytes = new Uint8Array(hashBuffer);
     const toHex = b => b.toString(16).padStart(2, "0");
-    const hashStr = Array.from(hashBytes, toHex).join("");
-    return hashStr == hash;
+
+    return Array.from(hashBytes, toHex).join("");
   },
 
   /**
-- 
2.31.1


From daac032f8a4e12451cda9ec6b1eca29f5a35521f Mon Sep 17 00:00:00 2001
From: grizzlyuser <grizzlyuser@protonmail.com>
Date: Wed, 30 Dec 2020 18:05:02 +0200
Subject: [PATCH 07/13] Client: Fetch and hash records from local dump

Read the records from local dumps. See [1] for details on how to prepare
custom dumps). Records are cached in the local IndexedDB, and the client
updates cached records each time there's a change. Also it verifies
integrity of the data. Then the list of current / created / updated /
deleted records is generated and emitted to every registered listener.

Change upstream signature validation mechanism to a simpler one.
Otherwise, it'd be necessary to sign local records, which is redundant,
because the application package should be signed already by the distro.

Instead of signature property from metadata records, json_dump_metadata
has been introduced. It contains the checksum of the records and size in
bytes. Also added app_build_id property for version checking and updates
of cached data.

Although it's possible to disable integrity checking via preference, it
seems to be not a good idea, because the logic that detects invalid
local data relies on it. In the context of local-only setup, data that
has been received from real Remote Settings server will not contain the
custom metadata, and thus will be considered invalid and then discarded,
while the client gets a chance to gracefully inform registered listeners
about these changes so that they can discard the data received before
the upgrade to local-only setup.

[1] https://firefox-source-docs.mozilla.org/services/common/services/RemoteSettings.html#initial-data
---
 services/settings/RemoteSettingsClient.jsm | 62 ++++++++++------------
 1 file changed, 27 insertions(+), 35 deletions(-)

diff --git a/services/settings/RemoteSettingsClient.jsm b/services/settings/RemoteSettingsClient.jsm
index 80dd563e11..1025ab33a2 100644
--- a/services/settings/RemoteSettingsClient.jsm
+++ b/services/settings/RemoteSettingsClient.jsm
@@ -556,11 +556,9 @@ class RemoteSettingsClient extends EventEmitter {
 
           // If the data is up-to-date but don't have metadata (records loaded from dump),
           // we fetch them and validate the signature immediately.
-          if (this.verifySignature && ObjectUtils.isEmpty(localMetadata)) {
+          if (this.verifySignature && ObjectUtils.isEmpty(localMetadata?.json_dump_metadata)) {
             console.debug(`${this.identifier} pull collection metadata`);
-            const metadata = await this.httpClient().getData({
-              query: { _expected: expectedTimestamp },
-            });
+            const { metadata } = await this._fetchChangeset(expectedTimestamp);
             await this.db.importChanges(metadata);
             // We don't bother validating the signature if the dump was just loaded. We do
             // if the dump was loaded at some other point (eg. from .get()).
@@ -813,32 +811,23 @@ class RemoteSettingsClient extends EventEmitter {
   async _validateCollectionSignature(records, timestamp, metadata) {
     const start = Cu.now() * 1000;
 
-    if (!metadata?.signature) {
+    if (!metadata?.json_dump_metadata) {
       throw new MissingSignatureError(this.identifier);
     }
 
-    if (!this._verifier) {
-      this._verifier = Cc[
-        "@mozilla.org/security/contentsignatureverifier;1"
-      ].createInstance(Ci.nsIContentSignatureVerifier);
-    }
-
-    // This is a content-signature field from an autograph response.
     const {
-      signature: { x5u, signature },
+      json_dump_metadata: { hash, size },
     } = metadata;
-    const certChain = await (await fetch(x5u)).text();
     // Merge remote records with local ones and serialize as canonical JSON.
     const serialized = await RemoteSettingsWorker.canonicalStringify(
       records,
       timestamp
     );
     if (
-      !(await this._verifier.asyncVerifyContentSignature(
-        serialized,
-        "p384ecdsa=" + signature,
-        certChain,
-        this.signerName
+      !(await RemoteSettingsWorker.checkContentHash(
+        new TextEncoder().encode(serialized),
+        size,
+        hash
       ))
     ) {
       throw new InvalidSignatureError(this.identifier);
@@ -1030,24 +1019,27 @@ class RemoteSettingsClient extends EventEmitter {
    * @param since timestamp of last sync (optional)
    */
   async _fetchChangeset(expectedTimestamp, since) {
-    const client = this.httpClient();
-    const {
-      metadata,
-      timestamp: remoteTimestamp,
-      changes: remoteRecords,
-    } = await client.execute(
-      {
-        path: `/buckets/${this.bucketName}/collections/${this.collectionName}/changeset`,
-      },
-      {
-        query: {
-          _expected: expectedTimestamp,
-          _since: since,
-        },
-      }
+    const { data } = await SharedUtils.loadJSONDump(
+      this.bucketName,
+      this.collectionName
     );
+    const remoteRecords = data ?? [];
+
+    const serialized = await RemoteSettingsWorker.canonicalStringify(
+      remoteRecords,
+      expectedTimestamp
+    );
+    const bytes = new TextEncoder().encode(serialized);
+    const metadata = {
+      app_build_id: Services.appinfo.appBuildID,
+      json_dump_metadata: {
+        hash: await RemoteSettingsWorker.getContentHash(bytes),
+        size: bytes.length,
+      },
+    }
+
     return {
-      remoteTimestamp,
+      remoteTimestamp: expectedTimestamp,
       metadata,
       remoteRecords,
     };
-- 
2.31.1


From 4d36e599e6b24e10960ebb978c038c66c5ade06d Mon Sep 17 00:00:00 2001
From: grizzlyuser <grizzlyuser@protonmail.com>
Date: Wed, 30 Dec 2020 18:42:56 +0200
Subject: [PATCH 08/13] Client: start deferred sync on get() or on()

The users of the RemoteSettingsClient.jsm can receive records from it in
two ways: by calling get(), and by subscribing to events by calling
on().

So hook a deferred sync whenever something calls these methods. Because
multiple of those calls can be made quite early and in very short time,
set up a deferred task that will be armed only when needed and only once
in a second. When the task is running it first checks if the local data
came from the dump of the current app build, and no-ops if true. If
false, it triggers a sync. Then adds a flag if the client has been
correctly synchronized with the dump, so that no metadata checking
occurs during the session.
---
 services/settings/RemoteSettingsClient.jsm | 30 +++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/services/settings/RemoteSettingsClient.jsm b/services/settings/RemoteSettingsClient.jsm
index 1025ab33a2..1cebf2bc29 100644
--- a/services/settings/RemoteSettingsClient.jsm
+++ b/services/settings/RemoteSettingsClient.jsm
@@ -16,6 +16,7 @@ XPCOMUtils.defineLazyModuleGetters(this, {
   ClientEnvironmentBase:
     "resource://gre/modules/components-utils/ClientEnvironment.jsm",
   Database: "resource://services-settings/Database.jsm",
+  DeferredTask: "resource://gre/modules/DeferredTask.jsm",
   Downloader: "resource://services-settings/Attachments.jsm",
   IDBHelpers: "resource://services-settings/IDBHelpers.jsm",
   KintoHttpClient: "resource://services-common/kinto-http-client.js",
@@ -30,6 +31,7 @@ XPCOMUtils.defineLazyModuleGetters(this, {
 XPCOMUtils.defineLazyGlobalGetters(this, ["fetch"]);
 
 const TELEMETRY_COMPONENT = "remotesettings";
+const DEFERRED_SYNC_DELAY_MILLISECONDS = 1000;
 
 XPCOMUtils.defineLazyGetter(this, "console", () => Utils.log);
 
@@ -259,6 +261,14 @@ class RemoteSettingsClient extends EventEmitter {
     this._lastCheckTimePref = lastCheckTimePref;
     this._verifier = null;
     this._syncRunning = false;
+    this._deferredSync = new DeferredTask(
+      async () => {
+        if (!this._syncRunning && !(await this._isSynced())) {
+          await this.sync();
+        }
+      },
+      DEFERRED_SYNC_DELAY_MILLISECONDS
+    );
 
     // This attribute allows signature verification to be disabled, when running tests
     // or when pulling data from a dev server.
@@ -290,6 +300,11 @@ class RemoteSettingsClient extends EventEmitter {
     );
   }
 
+  on(event, callback) {
+    super.on(event, callback);
+    this._deferredSync.arm();
+  }
+
   get identifier() {
     return `${this.bucketName}/${this.collectionName}`;
   }
@@ -353,6 +368,10 @@ class RemoteSettingsClient extends EventEmitter {
     try {
       let hasLocalData = await Utils.hasLocalData(this);
 
+      if (!(await this._isSynced())) {
+        throw new MissingSignatureError(this.identifier);
+      }
+
       if (syncIfEmpty && !hasLocalData) {
         // .get() was called before we had the chance to synchronize the local database.
         // We'll try to avoid returning an empty list.
@@ -414,7 +433,10 @@ class RemoteSettingsClient extends EventEmitter {
       // No need to verify signature on JSON dumps.
       // If local DB cannot be read, then we don't even try to do anything,
       // we return results early.
-      return this._filterEntries(data);
+      const filtered = this._filterEntries(data);
+      this._deferredSync.arm();
+
+      return filtered;
     }
 
     console.debug(
@@ -452,6 +474,12 @@ class RemoteSettingsClient extends EventEmitter {
     return final;
   }
 
+  async _isSynced() {
+    this._synced ||=
+      Services.appinfo.appBuildID === (await this.db.getMetadata())?.app_build_id;
+    return this._synced;
+  }
+
   /**
    * Synchronize the local database with the remote server.
    *
-- 
2.31.1


From defc4080596f5407a98f0c9f1a456f685226054f Mon Sep 17 00:00:00 2001
From: grizzlyuser <grizzlyuser@protonmail.com>
Date: Wed, 30 Dec 2020 18:53:51 +0200
Subject: [PATCH 09/13] Client: deep compare records if timestamps match

When the list of current / updated / deleted records is generated, their
modification timestamps are compared to detect the updates.

Although in practice this is unlikely to happen, in theory the
timestamp of some older record received from Remote Settings can match
with the modified record in the dump. Although JSON processing script
makes sure to add unique timestamps to each of the modified records,
it's still possible to update dumps manually and simply forget to update
timestamps. So serialize the records and compare them as strings to be
on the safe side. This should happen only once after upgrading to each
new version of the application, so is not likely to introduce any
noticeable performance issues.
---
 services/settings/RemoteSettingsClient.jsm | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/services/settings/RemoteSettingsClient.jsm b/services/settings/RemoteSettingsClient.jsm
index 1cebf2bc29..2c18c5cfb6 100644
--- a/services/settings/RemoteSettingsClient.jsm
+++ b/services/settings/RemoteSettingsClient.jsm
@@ -13,6 +13,7 @@ const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
 
 XPCOMUtils.defineLazyModuleGetters(this, {
   AppConstants: "resource://gre/modules/AppConstants.jsm",
+  CanonicalJSON: "resource://gre/modules/CanonicalJSON.jsm",
   ClientEnvironmentBase:
     "resource://gre/modules/components-utils/ClientEnvironment.jsm",
   Database: "resource://services-settings/Database.jsm",
@@ -1022,7 +1023,10 @@ class RemoteSettingsClient extends EventEmitter {
         const old = oldById.get(r.id);
         if (old) {
           oldById.delete(r.id);
-          if (r.last_modified != old.last_modified) {
+          if (
+            r.last_modified != old.last_modified ||
+            CanonicalJSON.stringify(r) != CanonicalJSON.stringify(old)
+          ) {
             syncResult.updated.push({ old, new: r });
           }
         } else {
-- 
2.31.1


From c2ee19f01bc37e15c7742af8a502ffaa10745a52 Mon Sep 17 00:00:00 2001
From: grizzlyuser <grizzlyuser@protonmail.com>
Date: Wed, 30 Dec 2020 19:01:39 +0200
Subject: [PATCH 10/13] Client: delete more data on cleanup

When the client detects the local data is invalid (i.e. it came from
real Remote Settings and can have unwanted records), delete not only
the records, but also the attachments that came with them, because they
too can be problematic. And last check time preference, because it's not
useful anyway when remote-settings.js doesn't do any polling for changes.

Note that attachments should be deleted before the records, because the
logic gets the data about the attachments from those records.
---
 services/settings/RemoteSettingsClient.jsm | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/services/settings/RemoteSettingsClient.jsm b/services/settings/RemoteSettingsClient.jsm
index 2c18c5cfb6..8b65dc0cba 100644
--- a/services/settings/RemoteSettingsClient.jsm
+++ b/services/settings/RemoteSettingsClient.jsm
@@ -221,7 +221,10 @@ class AttachmentDownloader extends Downloader {
   async deleteAll() {
     let allRecords = await this._client.db.list();
     return Promise.all(
-      allRecords.filter(r => !!r.attachment).map(r => this.delete(r))
+      allRecords.filter(r => !!r.attachment).map(r => {
+        this.delete(r);
+        this.deleteCached(r.id);
+      })
     );
   }
 }
@@ -982,7 +985,7 @@ class RemoteSettingsClient extends EventEmitter {
           // Signature failed, clear local DB because it contains
           // bad data (local + remote changes).
           console.debug(`${this.identifier} clear local data`);
-          await this.db.clear();
+          await this._clearAll();
           // Local data was tampered, throw and it will retry from empty DB.
           console.error(`${this.identifier} local data was corrupted`);
           throw new CorruptedDataError(this.identifier);
@@ -1004,7 +1007,7 @@ class RemoteSettingsClient extends EventEmitter {
             // _importJSONDump() only clears DB if dump is available,
             // therefore do it here!
             if (imported < 0) {
-              await this.db.clear();
+              await this._clearAll();
             }
           }
         }
@@ -1044,6 +1047,12 @@ class RemoteSettingsClient extends EventEmitter {
     return syncResult;
   }
 
+  async _clearAll() {
+    await this.attachments.deleteAll();
+    await this.db.clear();
+    Services.prefs.clearUserPref(this.lastCheckTimePref);
+  }
+
   /**
    * Fetch information from changeset endpoint.
    *
-- 
2.31.1


From 56d2af487f7077753ea4df6bd0b1e6c91ed7ab9f Mon Sep 17 00:00:00 2001
From: grizzlyuser <grizzlyuser@protonmail.com>
Date: Wed, 30 Dec 2020 19:07:56 +0200
Subject: [PATCH 11/13] Client: remove comparison of collection timestamps

In case if the cached data that came from real Remote Settings server
(before the upgrade to local-only setup) has collection timestamp, that
is newer than the packaged local dump, then this comparison logic can
lead to early return of old data, skipping the integrity checking and
necessary cleanup. So remove the checks.
---
 services/settings/RemoteSettingsClient.jsm | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/services/settings/RemoteSettingsClient.jsm b/services/settings/RemoteSettingsClient.jsm
index 8b65dc0cba..6274596591 100644
--- a/services/settings/RemoteSettingsClient.jsm
+++ b/services/settings/RemoteSettingsClient.jsm
@@ -917,14 +917,9 @@ class RemoteSettingsClient extends EventEmitter {
       updated: [],
       deleted: [],
     };
-    // If data wasn't changed, return empty sync result.
-    // This can happen when we update the signature but not the data.
     console.debug(
       `${this.identifier} local timestamp: ${localTimestamp}, remote: ${remoteTimestamp}`
     );
-    if (localTimestamp && remoteTimestamp < localTimestamp) {
-      return syncResult;
-    }
 
     const start = Cu.now() * 1000;
     await this.db.importChanges(metadata, remoteTimestamp, remoteRecords, {
-- 
2.31.1


From c009c1a9ba2477c9335921b706256f115ecfd498 Mon Sep 17 00:00:00 2001
From: grizzlyuser <grizzlyuser@protonmail.com>
Date: Wed, 30 Dec 2020 19:15:44 +0200
Subject: [PATCH 12/13] Attachments: load only from dump and drop cached

---
 services/settings/Attachments.jsm | 35 +++++++------------------------
 1 file changed, 8 insertions(+), 27 deletions(-)

diff --git a/services/settings/Attachments.jsm b/services/settings/Attachments.jsm
index 0eeb632799..eaa7db8c81 100644
--- a/services/settings/Attachments.jsm
+++ b/services/settings/Attachments.jsm
@@ -143,10 +143,11 @@ class Downloader {
       checkHash,
       attachmentId = record?.id,
       useCache = false,
-      fallbackToCache = false,
       fallbackToDump = false,
     } = options || {};
 
+    const fallbackToCache = false;
+
     if (!useCache) {
       // For backwards compatibility.
       // WARNING: Its return type is different from what's documented.
@@ -206,6 +207,7 @@ class Downloader {
         const newBuffer = await this.downloadAsBytes(record, {
           retries,
           checkHash,
+          dumpInfo,
         });
         const blob = new Blob([newBuffer]);
         if (useCache) {
@@ -241,7 +243,7 @@ class Downloader {
       }
 
       try {
-        return { ...(await cacheInfo.getResult()), _source: "cache_fallback" };
+        await this.cacheImpl.delete(attachmentId);
       } catch (e) {
         // Failed to read from cache, e.g. IndexedDB unusable.
         Cu.reportError(e);
@@ -278,7 +280,7 @@ class Downloader {
    * @returns {String} the absolute file path to the downloaded attachment.
    */
   async downloadToDisk(record, options = {}) {
-    const { retries = 3 } = options;
+    const retries = 0;
     const {
       attachment: { filename, size, hash },
     } = record;
@@ -335,31 +337,10 @@ class Downloader {
    */
   async downloadAsBytes(record, options = {}) {
     const {
-      attachment: { location, hash, size },
-    } = record;
-
-    const remoteFileUrl = (await this._baseAttachmentsURL()) + location;
+      dumpInfo = new LazyRecordAndBuffer(() => this._readAttachmentDump(attachmentId))
+    } = options;
 
-    const { retries = 3, checkHash = true } = options;
-    let retried = 0;
-    while (true) {
-      try {
-        const buffer = await this._fetchAttachment(remoteFileUrl);
-        if (!checkHash) {
-          return buffer;
-        }
-        if (await RemoteSettingsWorker.checkContentHash(buffer, size, hash)) {
-          return buffer;
-        }
-        // Content is corrupted.
-        throw new Downloader.BadContentError(location);
-      } catch (e) {
-        if (retried >= retries) {
-          throw e;
-        }
-      }
-      retried++;
-    }
+    return (await dumpInfo.getResult()).buffer;
   }
 
   /**
-- 
2.31.1


From 2035bd7a6ce1816417b619d3f1ce994a8b44ce9d Mon Sep 17 00:00:00 2001
From: grizzlyuser <grizzlyuser@protonmail.com>
Date: Wed, 30 Dec 2020 19:22:20 +0200
Subject: [PATCH 13/13] Disable CRLite entirely for now

It's designed to fetch the data from Remote Settings. One of the main
selling points is that new revocations can be pushed to the clients
within minutes. That won't work with local-only setup. Although (some?)
of the JSON dumps for it are in place, obviously the updates won't
happen that fast.

Right now CRLite doesn't enforce anything, and works just for telemetry
collection (which is hopefully disabled anyway). So disable the
preference right in the source code, so that the patch fails to apply
when the upstream decides to set it to enforcing mode by default.

The solution with CRLite is up for discussion. If necessary, it's
possible to make clients for blessed collections to communicate to real
Remote Settings server. For example, for collections related to
certificate revocations.
---
 modules/libpref/init/all.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index edca292681..da7e23d674 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -172,7 +172,7 @@ pref("security.cert_pinning.max_max_age_seconds", 5184000);
 // 0: Disable CRLite entirely
 // 1: Enable and check revocations via CRLite, but only collect telemetry
 // 2: Enable and enforce revocations via CRLite
-pref("security.pki.crlite_mode", 1);
+pref("security.pki.crlite_mode", 0);
 
 // Represents the expected certificate transparency log merge delay (including
 // the time to generate a CRLite filter). Currently 28 hours in seconds.
-- 
2.31.1

