[tor-dev] Proposal #349: Command state validation (for dropmark attacks)

[Mike Perry]

We've merged a draft of Proposal #349 to torspec:
https://gitlab.torproject.org/tpo/core/torspec/-/blob/main/proposals/349-command-state-validation.md

Also available on the tor spec site at:
https://spec.torproject.org/proposals/349-command-state-validation.html

This proposal is meant to deal with the third class of highly severe 
protocol side channels in tor: Dropped Cells. See Prop #344 for background:
https://spec.torproject.org/proposals/344-protocol-info-leaks.html

Note that there still are some details that need to be ironed out wrt 
how and when to perform checks that depend upon full parsing and 
protocol context, as opposed to just relay message command.

This work is part of Sponsor 112; arti-client support is due by EOY 2024.

C-Tor will not implement this proposal.

-- 
Mike Perry