Security/ProcessIsolation

Process isolation is designed to separate Firefox into multiple processes, each with the least amount of privilege necessary. In doing so, the potential damage for a large number of Firefox vulnerabilities can be reduced.

Project Goals

Reduce the damage for various types of vulnerabilities within Firefox. This is a defense in depth measure.

We will do so by:

• identifying high level of categories of threats that we could address via process isolation
• determining the architectural implications of mitigating each category
• selecting a threat model and architecture that will address it, and prototyping it
• determining whether the chosen model is actually feasible within the current Gecko architecture
• implementation roadmap
• implement it

Roadmap

• Put together a team of people willing to put in a sustained effort on process isolation design and prototyping (6+ month timeframe)
• Identify broad sets of vulnerabilities that might be mitigated by process isolation (high level threat model, here: Security/ProcessIsolation/ThreatModel
• Identify several potential architectures. A few that come to mind, there will be more:
  • Isolate entire Firefox process into low rights mode (sensitive I/O virtualized or brokered). Protects system from browser vulns but does not improve stability or inter-domain security.
  • Isolate Firefox into multiple processes (process per tab or process per top-level). Provides system protection, and stability benefits, but minimal inter-domain protections.
  • Isolate Firefox into separate process per domain. The most complex model, but provides system protection, stability, and inter-domain compartmentalization.
• Determine which sets of vulnerabilities could be addressed by different architectures
• Outline any operating system limitations and feasibility of each potential architecture on major OSes
• Pick a (straw man) architecture
• Develop a detailed threat model to understand how threats will be mitigated and where we might run into implementation problems for the given architecture
• Figure out how to address any design or implementation issues discovered
• Iterative the above 3 steps as necessary
• Implementation roadmap
  • Identify components affected and respective developers
  • Figure out milestones and beta requirements
  • Budget and schedule for external security review