[tension-atoi]

Scope

Compatibility mitigation for the existing historical user-owned in.gnu.os binary. This does not migrate or replace the modern Gnosix activation authority.

The September 2026 legacy binary tries to apply a TracingPolicy for sys_setuid, sys_connect, and sys_openat, but its _cgroup_slice parameter is discarded: neither process identity nor a real cgroup restriction is present. Installing tetra to silence the warning would risk activating an unscoped policy.

Changes

• Byte-pin the observed legacy executable (SHA-256) in a user-session ExecCondition guard.
• Decline new legacy service starts when the executable changes or tetra is present.
• Preserve human-owned unit, After=graphical-session.target, and modern authority separation.
• Add 6 hermetic allow/deny tests and register them in cargo xtask ci.
• Document scope, deployment, rollback, and the still-open LLM / /gnosis_shm / Tetragon migrations.

Qualification

• cargo xtask ci: 43/43 PASS, commit 007045eaa3aa9672e46b1b87b3f15379fc33efed, clean tree.
• Live workstation: ExecCondition exit 0; in.gnu.os.service active, 0 unexpected restarts; deployed files byte-identical to source.
• Negative tests: missing/replaced binary and fake tetra all refused. No host packages or privileges changed.
• Full forensic evidence retained locally under /mnt/workbench/evidence/runs/in-gnu-os-lifecycle-20261008/ and /mnt/workbench/evidence/runs/legacy-in-gnu-os-guard-full-ci-20261008/.

Remaining limitations

This guard is not Tetragon enforcement and does not monitor an already-running process. The legacy LLM and shared-memory warnings remain unresolved by design; no crashing Hyprland plugin was loaded. Cold-boot/session A→B and retiring the old D-Bus surfaces are separately unqualified.