Sandbox: degrade gracefully when the namespace jail is denied (unblocks ward#108) #153

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opened 2026-06-18 00:50:46 +00:00 by coilysiren · 0 comments

coilysiren commented

2026-06-18 00:50:46 +00:00

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Sandbox: degrade gracefully when the namespace jail is denied

cli/sandbox's user+mount namespace jail needs privileges some environments deny, so every sandboxed verb dies there. Two field failure modes (downstream ward#108):

clone denied (container without userns): fork/exec <bin>: operation not permitted
make-rprivate denied (restricted mount ns): sandbox: make-rprivate: permission denied

Fix

Auto-degrade: when a jailed child fails to start with EPERM/EACCES (sandbox.SetupDenied), shell.Runner retries the command unsandboxed and warns once. Side-effect-safe (the child never ran); a started-then-failed run is a real error and is never degraded.
Opt-out: CLIGUARD_NO_SANDBOX=1 makes Wrap no-op up front (covers both modes), for environments that are already the isolation boundary.

Unblocks ward container's in-container reaper (re-execs ward, denied by the container's restricted namespace). Downstream: ward#108, and the ward container entrypoint will export CLIGUARD_NO_SANDBOX.

Docs: docs/sandbox.md. Tests: NoSandbox, Wrap opt-out, SetupDenied.

## Sandbox: degrade gracefully when the namespace jail is denied `cli/sandbox`'s user+mount namespace jail needs privileges some environments deny, so every sandboxed verb dies there. Two field failure modes (downstream ward#108): - **clone denied** (container without userns): `fork/exec <bin>: operation not permitted` - **make-rprivate denied** (restricted mount ns): `sandbox: make-rprivate: permission denied` ### Fix - **Auto-degrade**: when a jailed child fails to *start* with EPERM/EACCES (`sandbox.SetupDenied`), `shell.Runner` retries the command unsandboxed and warns once. Side-effect-safe (the child never ran); a started-then-failed run is a real error and is never degraded. - **Opt-out**: `CLIGUARD_NO_SANDBOX=1` makes `Wrap` no-op up front (covers both modes), for environments that are already the isolation boundary. Unblocks `ward container`'s in-container reaper (re-execs ward, denied by the container's restricted namespace). Downstream: ward#108, and the ward container entrypoint will export `CLIGUARD_NO_SANDBOX`. Docs: docs/sandbox.md. Tests: NoSandbox, Wrap opt-out, SetupDenied.

coilysiren referenced this issue from a commit

2026-06-18 00:51:38 +00:00

feat(sandbox): degrade gracefully when namespace jail is denied + CLIGUARD_NO_SANDBOX

coilysiren closed this issue

2026-06-18 00:51:38 +00:00