landlock: Split denial logging from audit into common framework

Tracepoint emission requires the denial framework (layer identification,
request validation) without depending on CONFIG_AUDIT.  Separate the
denial logging infrastructure from the audit-specific code by
introducing a common log framework.

Create CONFIG_SECURITY_LANDLOCK_LOG, enabled by default when
CONFIG_AUDIT is set; a following commit extends it to CONFIG_TRACEPOINTS
when the first tracepoint consumer is added.  Move the common framework
(the request types, the layer identification and request validation, and
the landlock_log_denial() and landlock_log_free_domain() entry points)
into log.c and log.h, and keep the audit-specific record formatting in
audit.c. log.o is built for CONFIG_SECURITY_LANDLOCK_LOG and audit.o for
CONFIG_AUDIT, so the common framework is available to a tracepoints-only
build.  The entry points dispatch to no-op static inline audit stubs
without CONFIG_AUDIT, so the call sites stay unconditional.  Rename the
former landlock_log_drop_domain() to landlock_log_free_domain() to match
the landlock_free_domain tracepoint added in a following commit.

landlock_log_denial() counts denials even without audit, so its
declaration and no-op stub are guarded by CONFIG_SECURITY_LANDLOCK_LOG,
not CONFIG_AUDIT; a CONFIG_AUDIT guard would expose the stub and clash
with log.c's definition in a tracepoints-only build.

Widen the ID allocation (id.o and the landlock_init_id() /
landlock_get_id_range() declarations) and the log-state representation
(the domain_exec and log_subdomains_off credential fields, the
landlock_hierarchy log fields, and the code that maintains them) from
CONFIG_AUDIT to CONFIG_SECURITY_LANDLOCK_LOG, so each field and its
writer share one guard and are available to tracing without audit
support.

Widen the denial-path state that feeds the per-denial logging decision
the same way, so the "logged" verdict is computed identically whether or
not CONFIG_AUDIT is set.  Widening fown_layer is what keeps the
file-owner-signal path valid without audit: otherwise
hook_file_send_sigiotask() would leave layer_plus_one at zero, tripping
the is_valid_request() canary and dropping the LANDLOCK_SCOPE_SIGNAL
denial from tracing.

The ruleset-level quiet_masks stays on no CONFIG guard: it is builder
state validated and stored from user input, kept available so
LANDLOCK_ADD_RULE_QUIET flags are accepted and ignored, not rejected,
when CONFIG_SECURITY_LANDLOCK_LOG is disabled.

Cc: Günther Noack <gnoack@google.com>
Link: https://patch.msgid.link/20260811094338.288094-5-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>

0 files changed, 0 insertions, 0 deletions