selftests/landlock: Test filesystem denial blockers

Filesystem denial traces identify the policy change needed to allow a
request, so require exact blocker values rather than merely nonempty
output. Pin a READ_DIR denial to exactly one event with
blockers=read_dir. Pin a REFER-only mount denial to EPERM and exactly
one event with blockers=change_topology.

The mount child retains CAP_SYS_ADMIN so Landlock is the only expected
source of EPERM.  This prevents a later capability failure from masking
a Landlock regression; the trace-collecting parent remains unsandboxed.

Cc: Günther Noack <gnoack@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: https://patch.msgid.link/20260918185036.608651-8-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
This commit is contained in:
Mickaël Salaün 2026-09-18 20:50:30 +02:00
commit c6dea91d84
No known key found for this signature in database
GPG key ID: E5E3D0E88C82F6D2