App-level RBAC over the single shared PTY, enforced by the broker:
- The sandbox launcher becomes owner (superuser) and first driver; broadcasts
an encrypted {"_perm":"acl",owner,drivers} frame all clients track.
- /grant <user> and /revoke <user> (owner-only) delegate/withdraw drive rights
= delegating control of the shared (root) shell — the superuser-delegation ask.
- The broker honors {"_sbx":"input"} only from permitted drivers, keyed on the
SERVER-AUTHENTICATED sender (the message username the Sanic session stamps),
not a spoofable self-asserted field — closes the spec's identity-binding gap.
- F2 is gated: non-drivers get 'ask the owner to /grant you'; revoke drops drive
live. Roster shows roles: ⛧ owner · ◆ driver · • member.
Verified live (two TUIs): member blocked pre-grant, owner /grant member, member
then drives a command in the sandbox; roster + permission messages all correct.
cargo test: 4 pass.
Note: per the single-shared-PTY decision, drive-grant *is* the permission model;
per-user unix accounts/sudo would need per-user shells (future mode).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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