Exploring GrapheneOS secure allocator: Hardened Malloc

(synacktiv.com)

86 points | by r4um 13 hours ago ago

6 comments

  • pizlonator 4 hours ago ago

    The problem with these kinds of hardened allocators is that:

    - They impact performance.

    - They don’t prevent the attacker from pivoting a memory safety bug to remote execution.

    - They get oversold (like calling it “secure”).

    That’s not to say there aren’t allocator mitigations that help. It’s just that this isn’t it. Quarantining for example just means the attacker has to do a bit more acrobatics, but it won’t stop them.

    I think what Apple is doing with typed allocations is much more principled and they have data to prove it in their blog posts

    • manbash 2 hours ago ago

      > They don’t prevent the attacker from pivoting a memory safety bug to remote execution.

      I'm confused. Isn't this potentially preventing some classes of memory-safety bugs?

    • drnick1 4 hours ago ago

      Yes, but it also means you need an Apple device, and hence a locked down system. You also need to take all of Apple's privacy claims at face value. No thanks.

  • mrtesthah 7 hours ago ago

    Relatedly, check out Apple’s own kalloc_type allocator that they use with MTE as well as newer silicon-level changes for extremely broad memory integrity enforcement:

    https://security.apple.com/blog/memory-integrity-enforcement...