Deploying Simple AdBlocker on MacOS/iOS

Posted: 2024-01-17
Tags: Xcode, Security

Commercial ad blocking extensions make their money by collecting data on their user’s browsing. Very few open source projects have extensions for Safari, so we roll our own…

• Prerequisites
  • Acquire the Source Code
  • Select Team
• Deploy to MacOS
  • Build and Deploy the App
  • Enable Unsigned Safari Extensions
  • Enable the Extension in Safari
• Deploy to iOS
  • Build and Deploy the App
  • Trusting the Signing Certificate
  • Enable the Extension in Safari

Prerequisites

Apple’s Xcode IDE is necessary to compile and deploy the extension. It is free.

Either a paid Apple Developer Account is required, or a locally issued signing certificate.

Acquire the Source Code

• Open Xcode
• On the startup screen, click Clone Git Repository…
• In the text box at the top of the screen enter the repository URL: https://github.com/phasefactor/AdBlocker.git
• Click Clone.
• Select a location for Xcode to download the project and click Clone.

Select Team

• In the left side navigation pane, click on the root AdBlocker node of the tree.
• Open the Signing & Capabilities tab in the center pane.
• For BOTH the AdBlocker and AdBlocker Extension targets:
  • In the Signing section, click the Team dropdown.
  • Select the account you added earlier (or add the account).

Deploy to MacOS

Build and Deploy the App

• Select “My Mac” as the deployment destination:
  • In the top menu bar, click Product.
  • Click Destination.
  • Click My Mac.
• Build and run.
  • In the top menu bar, click Product.
  • Click Run

This should build and run the AdBlocker app, which contains the extension and registers it with Safari. The extension must still be turned on in Safari.

Enable Unsigned Safari Extensions

• Open Safari and open Settings by either:
  • Click Safari in the top menu bar, then click Settings….
  • Or press Command - , to open Settings directly.
• Open the Advanced tab.
• Click the checkbox next to Show features for web developers.
• Open the newly revealed Developer tab.
• Click the checkbox next to Allow unsigned extensions.

Enable the Extension in Safari

• Open Safari and open Settings by either:
  • Click Safari in the top menu bar, then click Settings….
  • Or press Command - , to open Settings directly.
• Open the Extensions tab.
• Click the checkbox next to AdBlocker Extension.
• Enable to extension in private browsing (if you want):
  • Click on AdBlocker Extension.
  • Click the checkbox next to Allow in Private Browsing.

Deploy to iOS

Build and Deploy the App

• Connect your iOS device to your development computer.
  • You may be asked whether to trust the computer.
• Select your iOS device as the deployment destination:
  • In the top menu bar, click Product.
  • Click Destination.
  • Click on your iOS device’s name.
• Build and run.
  • In the top menu bar, click Product.
  • Click Run

If this is the first thing deployed to the iOS device with this signing certificate, then the certificate must be manually added to the trusted list.

This should build and run the AdBlocker app, which contains the extension and registers it with Safari. The extension must still be turned on in Safari.

Trusting the Signing Certificate

Once you deploy the app to your iOS device:

• Open Settings.
• Click General.
• Click VPN & Device Management.
• Select the certificate and trust it.

Enable the Extension in Safari

• Open Settings.
• Click Safari.
• Click Extensions.
• Click AdBlocker Extension in the Allow these Extensions list.
• Click Allow Extension and (if you want) click Allow in Private Browsing.