SouveraineOS/saf/authority/01-session.md

Session authority

The Souveraine session has one authority. sessiond receives evidence from the system, applies Souveraine policy, exposes named verbs, and keeps the trail. The shell is its face. It is not a second policy engine.

This chapter owns the living architecture. The longer doctrine and audit records remain in SouveraineOS under docs/SESSION-AUTHORITY-DOCTRINE.md, docs/SESSION-TRUST-ARCHITECTURE.md, and docs/TRUST-BOUNDARY-MATRIX.md.

The authority it is, and the authorities it consumes

Classical Linux gives ambient authority to processes sharing a UID. It has several narrower authorities, but no single object that means "the state and permission of this person's session." Souveraine does not replace those authorities with hand-maintained booleans. It consumes them:

• the compositor owns what is presented and the Wayland lock protocol;
• logind owns seat/session facts, LockedHint, suspend, shutdown, and inhibitors;
• PAM owns authentication;
• Wayland idle protocols own compositor-observed idleness;
• NetworkManager owns link and bearer facts;
• the kernel and their owning daemons own device evidence.

sessiond is the one place where those truths become Souveraine policy and action. A shadow copy is not a second truth. If it can drift from the owner, it may be a cache with explicit invalidation, but it may not decide.

Who owns the lockscreen

Casey is the person who authenticates. Casey's Unix account must not therefore own the mechanism that decides whether the device is securely locked. The lockscreen is hostile-input-facing, present before Personal data is unlocked, and remains present after that key is evicted. It is a security target in its own right.

The target local principal is souveraine-session, distinct from all four other subjects:

• souveraine is the machine signer;
• souveraine-session runs sessiond and owns the secure lock lifecycle;
• casey is the human authentication and Personal-data subject;
• souvie, annie, and vanguard are agent principals;
• borrowed modes may act through casey, but own none of the lock boundary.

The same split applies on the laptop and phone. A larger screen does not make the human-owned lock process safer, and a phone form factor does not make an agent the session authority.

The compositor enforces ext-session-lock. Sessiond, running as souveraine-session, acquires and retains that protocol authority, owns the PAM conversation, decides transitions, and writes the trail. QuickShell may draw the rich face and request verbs, but it cannot release the secure lock by writing a boolean or dying. An agent may request lock and may receive an explicit step-up grant; no agent owns unlock.

Successful PAM authenticates Casey and permits the authority to install or release Casey's Personal-class key. It does not turn sessiond into Casey or give souveraine-session access to Casey's decrypted home. Credentials should cross only through the PAM conversation; the resulting grant is narrow, fresh, and auditable.

The pre-unlock surface owns only package code plus Ambient and tightly scoped Revealable state. It does not read agent memory, messages, photos, credentials, or Casey's Personal store. Notification previews and now-playing metadata are projected into the Revealable store before lock; the lockscreen does not reopen the Personal database after key eviction.

At boot, the compositor and lock authority rise without Casey's home, user manager, or agent substrate. The dedicated principal receives only the narrow Wayland socket/protocol and PAM access it needs, not membership that makes the whole human session readable. After the compositor acknowledges the secure lock, Personal keys may be evicted while the lock surface continues to draw.

This boundary is not built. souveraine-sessiond.service is currently a user unit with no User= setting, so it runs as whichever human user manager owns the graphical session. On the laptop, the machine-tier souveraine account exists and souveraine-session does not. The boot ordering is useful and fail-closed, but it is not yet an independent lockscreen principal.

Sixty percent agent, forty percent user

The agent owns device operation. If the system can perform an ordinary device operation, there should be an agent-reachable verb for it. A missing verb is a defect unless the operation crosses a user-only invariant.

The user uniquely owns being the user: credentials, fresh authentication, step-up consent, and the decision to cross a boundary whose meaning cannot be delegated. The user is not required to act as a remote control for mundane operations merely because the agent's path was never built.

This is the 60/40 split. It is not a percentage implemented in code. It is a design test for every capability surface.

Requests are not acknowledgements

The authority distinguishes intent, attempted action, and observed fact.

screenLocked can express a request or policy state. screenLockSecure means the compositor has actually established the secure lock. A request to lock is not permission to blank as though the lock were already held. The dark-panel path therefore requests lock, waits for acknowledgement within a fixed budget, and records a security error if the acknowledgement never arrives before the panel is blanked.

The same rule applies elsewhere:

• starting a systemd unit is not readiness;
• issuing a compositor command is not proof that a surface arrived;
• accepting a socket write is not proof that a state transition committed;
• a green package build is not proof that the device installed or exercised it.

The session start graph and its readiness boundary live in session start.

Capability tiers

Tier is metadata on the verb being guarded, checked at the authority. It is not a separate permissions subsystem in the shell.

Tier	Requirement	Typical reach
ambient	no authentication	time, weather, timers, media transport, non-personal questions
personal	the session is genuinely unlocked	messages, memory, contacts, fleet and conversation state
stepUp	fresh authentication for the named family	send, delete, publish, payment, physical access, revealing personal content on lock

Step-up does not unlock the session. It can grant a narrow action family or reveal content in place on the lock surface. A future grant therefore needs an action family, freshness, provenance, and expiry; "fingerprint succeeded" is not itself a session-wide capability.

Verbs, refusals, and inspection

Every operation exposed by sessiond should have one stable name and one decision point. The same capability may be rendered as a shell button, a body tool, or an agent request, but those are clients of the verb, not parallel implementations.

An authority-grade verb carries enough structure to answer:

• what was requested and by whom;
• what current state and evidence it used;
• which tier and inhibitor applied;
• whether it accepted, refused, or failed;
• what observable acknowledgement completed it;
• what belongs in the forensic trail.

Refusal is data. Stable refusal codes let a face explain, a caller retry only when retry is meaningful, and the trail distinguish policy from breakage. describe is the inspection surface: clients should not copy a verb list and guess which actions are live.

Idle and inhibitors

Idleness is evidence from the compositor, not a timer duplicated in every surface. Applications and system work can inhibit consequences, but an inhibitor is scoped, named, and inspectable. It is not a permanent alternate writer of panel or lock state.

The authority may decide to dim, lock, blank, doze, suspend, or stay awake. The state machine records that decision and the executor performs the action. No shell timer, hypridle listener, or device script gets an independent vote.

The boundary that exists today

The current local session socket is mode 0600 and accepts same-user callers. That is a useful local boundary, not the eventual attested capability system. A process running as the user can still reach more than the doctrine intends. The account and process boundary that turns peer credentials into an actual agent identity is specified in agent principals. Until it lands, Agent Health must describe a live agent as acting-as-human, not infer personhood or authority from a SeedID alone.

Also not yet true:

• step-up metadata is not wired across send, delete, push, or physical-access verbs;
• fingerprint authentication and short-lived reveal grants are not live on blueline;
• callers do not present capability tokens or binary attestation;
• every device operation does not yet have a complete describe-derived control surface;
• refusal and acknowledgement shapes are not yet uniform across every family.

Those are security and control gaps. A polished button does not close them.

Proof

Keep four claims separate:

1. source — the authority and verb exist in the tree;
2. package — CI built and signed the owning files and dependencies;
3. installed — the device owns those package files and no higher-priority local splint shadows them;
4. exercised — the real caller, authority, executor, and acknowledgement ran on the intended body.

The last is the only proof that a lock was secure, a panel moved, or an action crossed the boundary it claims.