The registry consults the open rows it has been parsing since P2, so
reaching a contract now takes a grant as well as a binding. A caller
without one is answered exactly as it would be for a name nobody ever
bound: same status, same empty reply, same absent capability, byte for
byte, and no log line on either path — klog_read is ungated, so a line on
one and not the other would be the oracle the design set out to remove.
Refusal and absence being one answer is what lets a supervisor later
narrow, fake or park a child's namespace without the child learning what
it was denied.
The manifest gains a third permission for a shape the plan did not
foresee: attestation is one hop, but the driver tree is three deep — the
PS/2 keyboard and mouse are spawned by ps2-bus, which the device manager
spawned — so no row could name them and PS/2 input would simply stop.
A supervise grant lets a delegate vouch for what its children *reach*,
never for what they claim; the bind path is untouched, and the laundering
deputy is still refused.
The review found the receive side of a rule this track had already
written down. Every process holds a sendable handle to the registrar —
resolve installs one for anyone who asks — and ipc_reply_wait never asked
who owned the endpoint, so a stranger could dequeue there: take the
provider endpoints riding bind requests, and answer other clients' opens
in the registrar's name. Receiving is the owner's privilege, like binding
a signal or a timer; sending remains anyone's.
Suite 109/109.
A protocol is reached by name now, not by a compile-time integer. Init is
PID 1 and already knows which binary it started, so init serves /protocol
as a vfs backend: bind claims a contract with the provider's endpoint
attached, open answers with that endpoint as the reply's capability, and
readdir lists what is bound with the task and binary behind it. The kernel
reserves the prefix — nothing may mount over it, under it, or unmount it —
and ServiceId, ipc_register and ipc_lookup are gone, their syscall numbers
left vacant.
A bind is authorized by who the caller *is*: the kernel-stamped binary
together with the supervising task's identity, matched against
/system/configuration/protocol.csv. Identity, not spelling — spawn is
ungated, so an attacker can run any bundled binary, and a name-only rule
would have let it launder grants through an init of its own making. A name
a live process holds is refused to everyone else; a dead one's is released.
Three review rounds against a hostile ring-3 process found what 108 green
tests could not, because the suite contains no attacker. Publishing init's
supervision endpoint as the registry put PID 1's mailbox in every process's
hands, where two forged bytes reached the shutdown path: privileged traffic
is now believed only from the task that holds the contract it speaks for.
A capability arriving on a request outlived every path that ignored it,
one handle per call until the table was full — in init, and in the harness
ten services share — so the arriving capability is owned by the turn and
released unless a handler says otherwise. And the kernel let anyone holding
an endpoint handle aim signals, timers, exit notices and interrupts at it:
binding now requires having created it.
Suite 108/108. The new protocol-registry case asserts eleven properties,
each one an attack that must fail.
Daniel Samson