fix(sandbox): report the real seccomp probe launcher error - #4061
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The seccomp notification probes hide the kernel error that caused them to fail. When install_listener fails on the launcher thread, the broker only observes a closed channel and reports notification launcher disappeared, discarding the errno. This PR joins the launcher thread on handover failure and propagates its real error for all three probes: probe_scalar_round_trip, probe_addfd_send, and probe_connected_sendto_fast_path. A new test spawns a disposable child with a seccomp filter that blocks SYS_seccomp and verifies the probe surfaces PermissionDenied with os error 1 (EPERM) instead of a generic message. Signed-off-by: fede-kamel <fkamelhar@gmail.com>
fede-kamel
requested review from
a team,
derekwaynecarr,
mrunalp and
sjenning
as code owners
October 1, 2026 16:38
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|
is this needed with #4051? |
4 of 6 tasks
Collaborator
|
Closing in favor of #4051 with the noted recommendation to pick up the raw OS err number handling from this PR. Thanks for the contribution, Fede! |
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Summary
The seccomp notification probes hide the kernel error that caused them
to fail. When install_listener fails on the launcher thread, the broker
only observes a closed channel and reports
notification launcher disappeared, discarding the errno. This makes several unrelatedfailures indistinguishable from the pre-5.19 WAIT_KILLABLE_RECV
rejection fixed in #3420, which is why #3842 looks like a regression
of that fix. This PR joins the launcher thread and propagates its
real error.
Related Issue
Refs #3842
Changes
launcher_failure()which joins the launcher thread on handoverfailure and returns its real error with the original ErrorKind
preserved, so the errno reaches the qualification report.
probe_scalar_round_trip, probe_addfd_send, and
probe_connected_sendto_fast_path.
without sending, and a launcher that panicked.
Testing
notification_probe_reports_rejected_listener_install. Itspawns a disposable child process, installs a filter that refuses
SECCOMP_SET_MODE_FILTER with EPERM while leaving the notification
size query working, and asserts the probe surfaces PermissionDenied
with os error 1. This models a restrictive host which the EINVAL
fallback cannot retry — distinct from a pre-5.19 kernel.
left: Other, right: PermissionDenied, confirming it catches the swallowed errorrather than passing vacuously.
cargo test -p openshell-isolation-interface: 29 lib + 25integration tests pass.
cargo clippy: clean.cargo checkon dependent crates: clean.