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event_dispatching.md

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Event Dispatching Logic Issues

Files Reviewed:

  • ui/events/event_dispatcher.cc
  • ui/events/event_processor.cc
  • ui/events/event_rewriter.cc
  • ui/events/event.cc
  • content/browser/renderer_host/render_frame_host_csp_context.cc

Potential Logic Flaws:

  • Event Injection: An attacker might inject malicious events.
  • Event Manipulation: An attacker could manipulate event properties.
  • Event Spoofing: An attacker might spoof legitimate events.
  • Timing Attacks: Analyze the potential for timing attacks.
  • Event Handler Manipulation: An attacker could manipulate the event handler list or inject malicious handlers. The DispatchEventToEventHandlers and OnHandlerDestroyed functions in event_dispatcher.cc need review.
  • Event Target Validation: Insufficient validation of event targets could allow events to be dispatched to unintended targets. The interaction between EventDispatcher and EventTarget needs further analysis.
  • Delegate Manipulation: Manipulating the EventDispatcherDelegate could allow interference with the event dispatching process. The interaction between EventDispatcher and its delegate needs review.
  • Event Lifecycle and State: Improper handling of event lifecycle or state could lead to vulnerabilities. The ScopedDispatchHelper class in event_dispatcher.cc should be analyzed.
  • Reentrancy and Concurrency: The event dispatching process could be vulnerable to reentrancy or race conditions. Synchronization mechanisms should be used.

Further Analysis and Potential Issues (Updated):

The ui/events/event_dispatcher.cc file implements core event dispatching logic. It uses a delegate pattern and a stack-based approach to manage event handlers. The DispatchEventToEventHandlers function iterates through handlers, dispatching sequentially. The DispatchEvent function handles the actual dispatch, including a target validity check. The code handles destroyed event handlers gracefully. Key filtering/validation functions are likely handled by the delegate and EventTarget classes, or within specific handlers. Potential security vulnerabilities include event filtering and validation, event injection points, event manipulation, asynchronous operations, resource exhaustion, input sanitization, and synchronization. Analysis of event_dispatcher.cc reveals potential vulnerabilities related to event handler manipulation, event target validation, delegate manipulation, event lifecycle and state, and reentrancy/concurrency.

Areas Requiring Further Investigation (Updated):

  • Event Filtering and Validation: Implement additional input validation. Review current filtering mechanisms. Consider detecting and blocking suspicious events.
  • Event Injection Points: Carefully review all event injection points. Implement robust input sanitization. Vet and validate external event sources. Consider secure communication channels.
  • Event Dispatching Mechanisms: Analyze event dispatching mechanisms for vulnerabilities.
  • Asynchronous Event Handling: Review asynchronous event handling for race conditions. Use synchronization primitives.
  • Event Prioritization: Analyze event prioritization for manipulation potential.
  • Resource Exhaustion: Review code for handling large event volumes. Implement rate limiting.
  • Input Sanitization: Implement robust input sanitization.
  • Synchronization Mechanisms: Verify appropriate synchronization mechanisms.
  • Event Handler Lifecycle: The lifecycle of event handlers, including their registration, deregistration, and destruction, needs to be thoroughly analyzed to prevent vulnerabilities related to handler manipulation or dangling pointers.
  • Delegate Interactions: The interaction between the EventDispatcher and the EventDispatcherDelegate should be carefully reviewed for potential vulnerabilities related to unauthorized access or manipulation of the event dispatching process.

CVE Analysis and Relevance:

This section will be updated with specific CVEs.

Secure Contexts and Event Dispatching:

Event dispatching is not directly tied to secure contexts, but its security is crucial. Vulnerabilities could allow event injection or manipulation. Robust input validation, sanitization, and error handling are essential.

Privacy Implications:

Event dispatching vulnerabilities could indirectly impact privacy by allowing manipulation of user interactions or access to sensitive information through events.

Additional Notes:

Analysis of render_frame_host_csp_context.cc revealed a potential vulnerability: unsanitized same-origin data in CSP violation reports. This highlights the importance of data sanitization. The VRP data suggests event handling vulnerabilities have been exploited. A thorough security audit of ui/events is recommended. Files reviewed: ui/events/event_dispatcher.cc, content/browser/renderer_host/render_frame_host_csp_context.cc.