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DOM Access Investigation & Future Strategy

This document consolidates the research and findings from the DOM access restoration efforts in v2.5.2.

Overview​

Teams for Linux requires DOM access to Microsoft Teams' React components for features like:

  • User status tracking
  • Custom background integration
  • System idle state management
  • Authentication flow enhancements

Critical React Breaking Changes Investigation​

Status: 🚨 CRITICAL - IMMEDIATE ACTION REQUIRED
Date: August 30, 2025

Key Findings​

CRITICAL DISCOVERY: The current ReactHandler implementation uses deprecated React APIs that were removed in React 18+ and will completely break when Microsoft Teams updates to React 19 (expected Q4 2025).

Current System​

  • Electron Version: 37.3.1
  • Chromium: 128.0.6613.186
  • ReactHandler Location: app/browser/tools/reactHandler.js

Vulnerable Code Patterns​

The current implementation relies on deprecated internal React APIs:

  • _reactRootContainer - Deprecated in React 18
  • _internalRoot - Internal API subject to removal
  • Direct DOM tree traversal of React internals

Risk Assessment​

  • Probability: HIGH - Microsoft Teams will eventually update to React 19
  • Timeline: Q4 2025 (React 19 release target)
  • Impact: CRITICAL - Complete feature breakdown
  • User Impact: Loss of core functionality

Solution Implemented (v2.5.2)​

Phase 1: DOM Access Restoration ✅ COMPLETED

  • Disabled contextIsolation and sandbox security features
  • Implemented security compensating controls:
    • Content Security Policy (CSP) headers
    • IPC channel validation and allowlisting
    • Teams domain validation
    • Payload sanitization
  • Added React version detection for monitoring

API Feasibility Investigation​

Date: August 30, 2025
Duration: ~45 minutes
Outcome: ✅ SUCCESSFUL for enterprise users

Executive Summary​

Microsoft Graph API approach is viable for enterprise users with work/school accounts, but has limitations for individual users with personal accounts. This aligns well with our primary user base.

Test Results by Account Type​

Enterprise Account Testing​

Account: Work/school account
Result: ✅ FULL SUCCESS

Capabilities Confirmed:

  • Full Microsoft Graph API access
  • User profile and presence data
  • Calendar integration capabilities
  • Authentication token management
  • Reduced re-login frequency

Setup Process:

  1. Azure app registration (straightforward)
  2. API permissions configuration
  3. Authentication flow integration

Personal Account Testing​

Account: Personal Microsoft account
Result: ⚠️ LIMITED SUCCESS

Limitations:

  • Azure app registration requires M365 Developer Program
  • Additional setup complexity
  • Reduced API scope for consumer accounts
  • May not justify implementation effort

Key Insights​

  1. Target Audience Alignment: Most Teams for Linux users are enterprise users
  2. Enhanced Features: API provides capabilities beyond DOM access
  3. Authentication Benefits: Significant reduction in re-login issues
  4. Future Resilience: Less dependence on Teams UI changes

Future Strategy: Hybrid API + DOM Approach​

Phase 2 Implementation Plan​

Build API integration ON TOP of current DOM implementation for enhanced functionality:

Architecture​

  • API-first: Try API calls first when credentials available
  • DOM fallback: Fall back to existing DOM methods when API unavailable
  • User choice: Optional API setup, works without configuration
  • Gradual migration: Replace DOM methods with APIs incrementally

Benefits​

  • Enhanced features: API provides capabilities beyond DOM access
  • Better authentication: Reduced re-login issues for enterprise users
  • Future resilience: Less dependence on Teams UI changes
  • No functionality loss: DOM fallback ensures all current features work

Implementation Priorities​

  1. User presence/status management - High impact, stable API
  2. Authentication flow optimization - Addresses major user pain point
  3. Calendar integration - New capability not possible with DOM
  4. Profile and org data - Enhanced user experience

Security Considerations​

Current Approach (v2.5.2)​

While contextIsolation and sandbox are disabled for DOM access, comprehensive compensating controls are implemented:

Technical Controls​

  • Content Security Policy: Prevents malicious script injection
  • IPC Validation: Channel allowlisting with payload sanitization
  • Domain Validation: Restricts DOM access to legitimate Teams domains
  • Input Sanitization: Prevents prototype pollution attacks

Instead of relying solely on Electron security features, users should adopt system-level sandboxing:

Available Options:

  • Flatpak: Built-in isolation, available via Flathub
  • Snap packages: Application confinement with auto-updates
  • AppArmor/SELinux: Most Linux distros include these by default
  • Manual sandboxing: firejail or bubblewrap for custom setups

Why System-Level Sandboxing > Application-Level​

  1. Preserves functionality: DOM access remains intact
  2. Better security: OS-level controls more robust than Electron sandbox
  3. User choice: Flexible security levels based on needs
  4. Future-proof: Works regardless of Teams/React changes

Implementation Status​

Phase 1: DOM Access Restoration ✅ COMPLETED (v2.5.2)​

  • Security features disabled (contextIsolation: false, sandbox: false)
  • CSP compensating controls implemented
  • IPC validation system created
  • React version detection added
  • ReactHandler functionality restored
  • System-level security recommendations documented

Phase 2: Hybrid API Integration 🚧 PLANNED​

  • Microsoft Graph integration for enterprise users
  • API-first with DOM fallback architecture
  • Enhanced authentication flow
  • Calendar and presence API integration
  • Gradual migration of DOM-dependent features

Monitoring & Maintenance​

React Version Monitoring​

The application now includes automatic React version detection to monitor for breaking changes:

// Implemented in app/browser/tools/reactHandler.js
_detectAndLogReactVersion() {
  // Multiple detection methods for reliability
  // Logs version information for monitoring
}

Future Considerations​

  1. Regular monitoring of Teams React version updates
  2. API migration timeline based on React update schedules
  3. User communication about security recommendations
  4. Gradual feature enhancement through hybrid API approach

References​