security/landlock/log.c - pub/scm/linux/kernel/git/gregkh/tty - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Landlock - Log helpers
  *
  * Copyright © 2023-2025 Microsoft Corporation
  * Copyright © 2026 Cloudflare, Inc.
  */

 #include <kunit/test.h>
 #include <linux/bitops.h>
 #include <uapi/linux/landlock.h>

 #include "access.h"
 #include "audit.h"
 #include "common.h"
 #include "cred.h"
 #include "domain.h"
 #include "limits.h"
 #include "log.h"
 #include "ruleset.h"
 #include "trace.h"

 static struct landlock_hierarchy *
 get_hierarchy(const struct landlock_domain *const domain, const size_t layer)
 {
 	struct landlock_hierarchy *hierarchy = domain->hierarchy;
 	ssize_t i;

 	if (WARN_ON_ONCE(layer >= domain->num_layers))
 		return hierarchy;

 	for (i = domain->num_layers - 1; i > layer; i--) {
 		if (WARN_ON_ONCE(!hierarchy->parent))
 			break;

 		hierarchy = hierarchy->parent;
 	}

 	return hierarchy;
 }

 #ifdef CONFIG_SECURITY_LANDLOCK_KUNIT_TEST

 static void test_get_hierarchy(struct kunit *const test)
 {
 	struct landlock_hierarchy dom0_hierarchy = {
 		.id = 10,
 	};
 	struct landlock_hierarchy dom1_hierarchy = {
 		.parent = &dom0_hierarchy,
 		.id = 20,
 	};
 	struct landlock_hierarchy dom2_hierarchy = {
 		.parent = &dom1_hierarchy,
 		.id = 30,
 	};
 	struct landlock_domain dom2 = {
 		.hierarchy = &dom2_hierarchy,
 		.num_layers = 3,
 	};

 	KUNIT_EXPECT_EQ(test, 10, get_hierarchy(&dom2, 0)->id);
 	KUNIT_EXPECT_EQ(test, 20, get_hierarchy(&dom2, 1)->id);
 	KUNIT_EXPECT_EQ(test, 30, get_hierarchy(&dom2, 2)->id);
 	/* KUNIT_EXPECT_EQ(test, 30, get_hierarchy(&dom2, -1)->id); */
 }

 #endif /* CONFIG_SECURITY_LANDLOCK_KUNIT_TEST */

 /* Get the youngest layer that denied the access_request. */
 static size_t get_denied_layer(const struct landlock_domain *const domain,
 			       access_mask_t *const access_request,
 			       const struct layer_masks *masks)
 {
 	for (ssize_t i = ARRAY_SIZE(masks->layers) - 1; i >= 0; i--) {
 		if (masks->layers[i].access & *access_request) {
 			*access_request &= masks->layers[i].access;
 			return i;
 		}
 	}

 	/* Not found - fall back to default values */
 	*access_request = 0;
 	return domain->num_layers - 1;
 }

 #ifdef CONFIG_SECURITY_LANDLOCK_KUNIT_TEST

 static void test_get_denied_layer(struct kunit *const test)
 {
 	const struct landlock_domain dom = {
 		.num_layers = 5,
 	};
 	const struct layer_masks masks = {
 		.layers[0].access = LANDLOCK_ACCESS_FS_EXECUTE |
 				    LANDLOCK_ACCESS_FS_READ_DIR,
 		.layers[1].access = LANDLOCK_ACCESS_FS_READ_FILE |
 				    LANDLOCK_ACCESS_FS_READ_DIR,
 		.layers[2].access = LANDLOCK_ACCESS_FS_REMOVE_DIR,
 	};
 	access_mask_t access;

 	access = LANDLOCK_ACCESS_FS_EXECUTE;
 	KUNIT_EXPECT_EQ(test, 0, get_denied_layer(&dom, &access, &masks));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_EXECUTE);

 	access = LANDLOCK_ACCESS_FS_READ_FILE;
 	KUNIT_EXPECT_EQ(test, 1, get_denied_layer(&dom, &access, &masks));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_READ_FILE);

 	access = LANDLOCK_ACCESS_FS_READ_DIR;
 	KUNIT_EXPECT_EQ(test, 1, get_denied_layer(&dom, &access, &masks));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_READ_DIR);

 	access = LANDLOCK_ACCESS_FS_READ_FILE | LANDLOCK_ACCESS_FS_READ_DIR;
 	KUNIT_EXPECT_EQ(test, 1, get_denied_layer(&dom, &access, &masks));
 	KUNIT_EXPECT_EQ(test, access,
 			LANDLOCK_ACCESS_FS_READ_FILE |
 				LANDLOCK_ACCESS_FS_READ_DIR);

 	access = LANDLOCK_ACCESS_FS_EXECUTE | LANDLOCK_ACCESS_FS_READ_DIR;
 	KUNIT_EXPECT_EQ(test, 1, get_denied_layer(&dom, &access, &masks));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_READ_DIR);

 	access = LANDLOCK_ACCESS_FS_WRITE_FILE;
 	KUNIT_EXPECT_EQ(test, 4, get_denied_layer(&dom, &access, &masks));
 	KUNIT_EXPECT_EQ(test, access, 0);
 }

 #endif /* CONFIG_SECURITY_LANDLOCK_KUNIT_TEST */

 static size_t
 get_layer_from_deny_masks(access_mask_t *const access_request,
 			  const access_mask_t all_existing_optional_access,
 			  const deny_masks_t deny_masks,
 			  optional_access_t quiet_optional_accesses,
 			  bool *quiet)
 {
 	const unsigned long access_opt = all_existing_optional_access;
 	const unsigned long access_req = *access_request;
 	access_mask_t missing = 0;
 	size_t youngest_layer = 0;
 	size_t access_index = 0;
 	unsigned long access_bit;
 	bool should_quiet = false;

 	/* This will require change with new object types. */
 	WARN_ON_ONCE(access_opt != _LANDLOCK_ACCESS_FS_OPTIONAL);

 	for_each_set_bit(access_bit, &access_opt,
 			 BITS_PER_TYPE(access_mask_t)) {
 		if (access_req & BIT(access_bit)) {
 			const size_t layer =
 				(deny_masks >>
 				 (access_index *
 				  HWEIGHT(LANDLOCK_MAX_NUM_LAYERS - 1))) &
 				(LANDLOCK_MAX_NUM_LAYERS - 1);
 			const bool layer_has_quiet =
 				!!(quiet_optional_accesses & BIT(access_index));

 			if (layer > youngest_layer) {
 				youngest_layer = layer;
 				missing = BIT(access_bit);
 				should_quiet = layer_has_quiet;
 			} else if (layer == youngest_layer) {
 				missing |= BIT(access_bit);
 				/*
 				 * Whether the layer has rules with quiet flag
 				 * covering the file accessed does not depend on
 				 * the access, and so the following
 				 * WARN_ON_ONCE() should not fail.
 				 */
 				WARN_ON_ONCE(should_quiet && !layer_has_quiet);
 				should_quiet = layer_has_quiet;
 			}
 		}
 		access_index++;
 	}

 	*access_request = missing;
 	*quiet = should_quiet;
 	return youngest_layer;
 }

 #ifdef CONFIG_SECURITY_LANDLOCK_KUNIT_TEST

 static void test_get_layer_from_deny_masks(struct kunit *const test)
 {
 	deny_masks_t deny_mask;
 	access_mask_t access;
 	optional_access_t quiet_optional_accesses;
 	bool quiet;

 	/* truncate:0 ioctl_dev:2 */
 	deny_mask = 0x20;
 	quiet_optional_accesses = 0;

 	access = LANDLOCK_ACCESS_FS_TRUNCATE;
 	KUNIT_EXPECT_EQ(test, 0,
 			get_layer_from_deny_masks(
 				&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
 				deny_mask, quiet_optional_accesses, &quiet));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_TRUNCATE);
 	KUNIT_EXPECT_EQ(test, quiet, false);

 	access = LANDLOCK_ACCESS_FS_IOCTL_DEV;
 	KUNIT_EXPECT_EQ(test, 2,
 			get_layer_from_deny_masks(
 				&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
 				deny_mask, quiet_optional_accesses, &quiet));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_IOCTL_DEV);
 	KUNIT_EXPECT_EQ(test, quiet, false);

 	access = LANDLOCK_ACCESS_FS_TRUNCATE | LANDLOCK_ACCESS_FS_IOCTL_DEV;
 	KUNIT_EXPECT_EQ(test, 2,
 			get_layer_from_deny_masks(
 				&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
 				deny_mask, quiet_optional_accesses, &quiet));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_IOCTL_DEV);
 	KUNIT_EXPECT_EQ(test, quiet, false);

 	/* layer denying truncate: quiet, ioctl: not quiet */
 	quiet_optional_accesses = 0b01;

 	access = LANDLOCK_ACCESS_FS_TRUNCATE;
 	KUNIT_EXPECT_EQ(test, 0,
 			get_layer_from_deny_masks(
 				&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
 				deny_mask, quiet_optional_accesses, &quiet));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_TRUNCATE);
 	KUNIT_EXPECT_EQ(test, quiet, true);

 	access = LANDLOCK_ACCESS_FS_IOCTL_DEV;
 	KUNIT_EXPECT_EQ(test, 2,
 			get_layer_from_deny_masks(
 				&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
 				deny_mask, quiet_optional_accesses, &quiet));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_IOCTL_DEV);
 	KUNIT_EXPECT_EQ(test, quiet, false);

 	access = LANDLOCK_ACCESS_FS_TRUNCATE | LANDLOCK_ACCESS_FS_IOCTL_DEV;
 	KUNIT_EXPECT_EQ(test, 2,
 			get_layer_from_deny_masks(
 				&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
 				deny_mask, quiet_optional_accesses, &quiet));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_IOCTL_DEV);
 	KUNIT_EXPECT_EQ(test, quiet, false);

 	/* Reverse order - truncate:2 ioctl_dev:0 */
 	deny_mask = 0x02;
 	quiet_optional_accesses = 0;

 	access = LANDLOCK_ACCESS_FS_TRUNCATE;
 	KUNIT_EXPECT_EQ(test, 2,
 			get_layer_from_deny_masks(
 				&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
 				deny_mask, quiet_optional_accesses, &quiet));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_TRUNCATE);
 	KUNIT_EXPECT_EQ(test, quiet, false);

 	access = LANDLOCK_ACCESS_FS_IOCTL_DEV;
 	KUNIT_EXPECT_EQ(test, 0,
 			get_layer_from_deny_masks(
 				&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
 				deny_mask, quiet_optional_accesses, &quiet));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_IOCTL_DEV);
 	KUNIT_EXPECT_EQ(test, quiet, false);

 	access = LANDLOCK_ACCESS_FS_TRUNCATE | LANDLOCK_ACCESS_FS_IOCTL_DEV;
 	KUNIT_EXPECT_EQ(test, 2,
 			get_layer_from_deny_masks(
 				&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
 				deny_mask, quiet_optional_accesses, &quiet));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_TRUNCATE);
 	KUNIT_EXPECT_EQ(test, quiet, false);

 	/* layer denying truncate: quiet, ioctl: not quiet */
 	quiet_optional_accesses = 0b01;

 	access = LANDLOCK_ACCESS_FS_TRUNCATE;
 	KUNIT_EXPECT_EQ(test, 2,
 			get_layer_from_deny_masks(
 				&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
 				deny_mask, quiet_optional_accesses, &quiet));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_TRUNCATE);
 	KUNIT_EXPECT_EQ(test, quiet, true);

 	access = LANDLOCK_ACCESS_FS_IOCTL_DEV;
 	KUNIT_EXPECT_EQ(test, 0,
 			get_layer_from_deny_masks(
 				&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
 				deny_mask, quiet_optional_accesses, &quiet));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_IOCTL_DEV);
 	KUNIT_EXPECT_EQ(test, quiet, false);

 	access = LANDLOCK_ACCESS_FS_TRUNCATE | LANDLOCK_ACCESS_FS_IOCTL_DEV;
 	KUNIT_EXPECT_EQ(test, 2,
 			get_layer_from_deny_masks(
 				&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
 				deny_mask, quiet_optional_accesses, &quiet));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_TRUNCATE);
 	KUNIT_EXPECT_EQ(test, quiet, true);

 	/* layer denying truncate: not quiet, ioctl: quiet */
 	quiet_optional_accesses = 0b10;

 	access = LANDLOCK_ACCESS_FS_TRUNCATE;
 	KUNIT_EXPECT_EQ(test, 2,
 			get_layer_from_deny_masks(
 				&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
 				deny_mask, quiet_optional_accesses, &quiet));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_TRUNCATE);
 	KUNIT_EXPECT_EQ(test, quiet, false);

 	access = LANDLOCK_ACCESS_FS_IOCTL_DEV;
 	KUNIT_EXPECT_EQ(test, 0,
 			get_layer_from_deny_masks(
 				&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
 				deny_mask, quiet_optional_accesses, &quiet));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_IOCTL_DEV);
 	KUNIT_EXPECT_EQ(test, quiet, true);

 	access = LANDLOCK_ACCESS_FS_TRUNCATE | LANDLOCK_ACCESS_FS_IOCTL_DEV;
 	KUNIT_EXPECT_EQ(test, 2,
 			get_layer_from_deny_masks(
 				&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
 				deny_mask, quiet_optional_accesses, &quiet));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_TRUNCATE);
 	KUNIT_EXPECT_EQ(test, quiet, false);

 	/* truncate:15 ioctl_dev:15 */
 	deny_mask = 0xff;
 	quiet_optional_accesses = 0;

 	access = LANDLOCK_ACCESS_FS_TRUNCATE;
 	KUNIT_EXPECT_EQ(test, 15,
 			get_layer_from_deny_masks(
 				&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
 				deny_mask, quiet_optional_accesses, &quiet));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_TRUNCATE);
 	KUNIT_EXPECT_EQ(test, quiet, false);

 	access = LANDLOCK_ACCESS_FS_TRUNCATE | LANDLOCK_ACCESS_FS_IOCTL_DEV;
 	KUNIT_EXPECT_EQ(test, 15,
 			get_layer_from_deny_masks(
 				&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
 				deny_mask, quiet_optional_accesses, &quiet));
 	KUNIT_EXPECT_EQ(test, access,
 			LANDLOCK_ACCESS_FS_TRUNCATE |
 				LANDLOCK_ACCESS_FS_IOCTL_DEV);
 	KUNIT_EXPECT_EQ(test, quiet, false);

 	/* Both quiet (same layer so quietness must be the same) */
 	quiet_optional_accesses = 0b11;

 	access = LANDLOCK_ACCESS_FS_TRUNCATE;
 	KUNIT_EXPECT_EQ(test, 15,
 			get_layer_from_deny_masks(
 				&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
 				deny_mask, quiet_optional_accesses, &quiet));
 	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_TRUNCATE);
 	KUNIT_EXPECT_EQ(test, quiet, true);

 	access = LANDLOCK_ACCESS_FS_TRUNCATE | LANDLOCK_ACCESS_FS_IOCTL_DEV;
 	KUNIT_EXPECT_EQ(test, 15,
 			get_layer_from_deny_masks(
 				&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
 				deny_mask, quiet_optional_accesses, &quiet));
 	KUNIT_EXPECT_EQ(test, access,
 			LANDLOCK_ACCESS_FS_TRUNCATE |
 				LANDLOCK_ACCESS_FS_IOCTL_DEV);
 	KUNIT_EXPECT_EQ(test, quiet, true);
 }

 #endif /* CONFIG_SECURITY_LANDLOCK_KUNIT_TEST */

 static bool is_valid_request(const struct landlock_request *const request)
 {
 	if (WARN_ON_ONCE(request->layer_plus_one > LANDLOCK_MAX_NUM_LAYERS))
 		return false;

 	if (WARN_ON_ONCE(!(!!request->layer_plus_one ^ !!request->access)))
 		return false;

 	if (request->access) {
 		if (WARN_ON_ONCE(!(!!request->layer_masks ^
 				   !!request->all_existing_optional_access)))
 			return false;
 	} else {
 		if (WARN_ON_ONCE(request->layer_masks ||
 				 request->all_existing_optional_access))
 			return false;
 	}

 	if (request->deny_masks) {
 		if (WARN_ON_ONCE(!request->all_existing_optional_access))
 			return false;
 		static_assert(sizeof(request->all_existing_optional_access) ==
 			      sizeof(u32));
 		if (WARN_ON_ONCE(
 			    request->quiet_optional_accesses >=
 			    BIT(hweight32(
 				    request->all_existing_optional_access))))
 			return false;
 	}

 	return true;
 }

 static access_mask_t
 pick_access_mask_for_request_type(const enum landlock_request_type type,
 				  const struct access_masks access_masks)
 {
 	switch (type) {
 	case LANDLOCK_REQUEST_FS_ACCESS:
 		return access_masks.fs;
 	case LANDLOCK_REQUEST_NET_ACCESS:
 		return access_masks.net;
 	default:
 		WARN_ONCE(1, "Invalid request type %d passed to %s", type,
 			  __func__);
 		return 0;
 	}
 }

 /*
  * Whether a quiet rule silences the denial: the rule must cover the whole
  * denied access in the layer that denied it (a quiet rule in a non-denying
  * layer does not suppress the denial).
  */
 static bool
 is_denial_quieted(const struct landlock_request *const request,
 		  const struct landlock_hierarchy *const youngest_denied,
 		  const access_mask_t missing, const bool object_quiet_flag)
 {
 	if (object_quiet_flag) {
 		const access_mask_t quiet_mask =
 			pick_access_mask_for_request_type(
 				request->type, youngest_denied->quiet_masks);

 		return (quiet_mask & missing) == missing;
 	}

 	/*
 	 * Either the object is not quiet, or this is a scope request.  We check
 	 * request->type to distinguish between the two cases.
 	 */
 	switch (request->type) {
 	case LANDLOCK_REQUEST_SCOPE_SIGNAL:
 		return !!(youngest_denied->quiet_masks.scope &
 			  LANDLOCK_SCOPE_SIGNAL);
 	case LANDLOCK_REQUEST_SCOPE_ABSTRACT_UNIX_SOCKET:
 		return !!(youngest_denied->quiet_masks.scope &
 			  LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET);
 	/*
 	 * Leave LANDLOCK_REQUEST_PTRACE and LANDLOCK_REQUEST_FS_CHANGE_TOPOLOGY
 	 * unhandled for now - they are never quiet.
 	 */
 	default:
 		return false;
 	}
 }

 /*
  * Computes whether a denial from youngest_denied is selected for logging by the
  * domain's policy: its logging must not be disabled (by both per-execution
  * flags being off, or by an ancestor's
  * LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF), the per-execution flag matching
  * same_exec must be set, and no quiet rule may cover the denied access.
  * landlock_log_denial() computes this once and passes it to
  * landlock_audit_denial(), which additionally requires audit_enabled.
  */
 static bool
 is_denial_logged(const struct landlock_request *const request,
 		 const struct landlock_hierarchy *const youngest_denied,
 		 const access_mask_t missing, const bool same_exec,
 		 const bool object_quiet_flag)
 {
 	if (READ_ONCE(youngest_denied->log_status) == LANDLOCK_LOG_DISABLED)
 		return false;

 	if (!(same_exec ? youngest_denied->log_same_exec :
 			  youngest_denied->log_new_exec))
 		return false;

 	return !is_denial_quieted(request, youngest_denied, missing,
 				  object_quiet_flag);
 }

 /**
  * landlock_log_denial - Log a denied access
  *
  * @subject: The Landlock subject's credential denying an action.
  * @request: Detail of the user space request.
  */
 void landlock_log_denial(const struct landlock_cred_security *const subject,
 			 const struct landlock_request *const request)
 {
 	struct landlock_hierarchy *youngest_denied;
 	size_t youngest_layer;
 	access_mask_t missing;
 	bool object_quiet_flag = false;

 	if (WARN_ON_ONCE(!subject || !subject->domain ||
 			 !subject->domain->hierarchy || !request))
 		return;

 	if (!is_valid_request(request))
 		return;

 	missing = request->access;
 	if (missing) {
 		/* Gets the nearest domain that denies the request. */
 		if (request->layer_masks) {
 			youngest_layer = get_denied_layer(subject->domain,
 							  &missing,
 							  request->layer_masks);
 			object_quiet_flag =
 				request->layer_masks->layers[youngest_layer]
 					.quiet;
 		} else {
 			youngest_layer = get_layer_from_deny_masks(
 				&missing, _LANDLOCK_ACCESS_FS_OPTIONAL,
 				request->deny_masks,
 				request->quiet_optional_accesses,
 				&object_quiet_flag);
 		}
 		youngest_denied =
 			get_hierarchy(subject->domain, youngest_layer);
 	} else {
 		youngest_layer = request->layer_plus_one - 1;
 		youngest_denied =
 			get_hierarchy(subject->domain, youngest_layer);
 	}

 	const bool same_exec = !!(subject->domain_exec & BIT(youngest_layer));
 	const bool logged = is_denial_logged(request, youngest_denied, missing,
 					     same_exec, object_quiet_flag);

 	/*
 	 * Consistently keeps track of the number of denied access requests even
 	 * if audit is currently disabled, or if audit rules currently exclude
 	 * this record type, or if landlock_restrict_self(2)'s flags quiet logs.
 	 */
 	atomic64_inc(&youngest_denied->num_denials);

 	landlock_trace_denial(request, youngest_denied, missing, same_exec,
 			      logged);
 	landlock_audit_denial(request, youngest_denied, missing, logged);
 }

 /**
  * landlock_log_free_domain - Log domain deallocation
  *
  * @hierarchy: The domain's hierarchy being deallocated.
  *
  * Called from landlock_put_domain_deferred() (via a work queue scheduled by
  * hook_cred_free()) or directly from landlock_put_domain().
  */
 void landlock_log_free_domain(const struct landlock_hierarchy *const hierarchy)
 {
 	if (WARN_ON_ONCE(!hierarchy))
 		return;

 	landlock_trace_free_domain(hierarchy);
 	landlock_audit_free_domain(hierarchy);
 }

 #ifdef CONFIG_SECURITY_LANDLOCK_KUNIT_TEST

 static struct kunit_case test_cases[] = {
 	/* clang-format off */
 	KUNIT_CASE(test_get_hierarchy),
 	KUNIT_CASE(test_get_denied_layer),
 	KUNIT_CASE(test_get_layer_from_deny_masks),
 	{}
 	/* clang-format on */
 };

 static struct kunit_suite test_suite = {
 	.name = "landlock_log",
 	.test_cases = test_cases,
 };

 kunit_test_suite(test_suite);

 #endif /* CONFIG_SECURITY_LANDLOCK_KUNIT_TEST */
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Landlock - Log helpers
	*
	* Copyright © 2023-2025 Microsoft Corporation
	* Copyright © 2026 Cloudflare, Inc.
	*/

	#include <kunit/test.h>
	#include <linux/bitops.h>
	#include <uapi/linux/landlock.h>

	#include "access.h"
	#include "audit.h"
	#include "common.h"
	#include "cred.h"
	#include "domain.h"
	#include "limits.h"
	#include "log.h"
	#include "ruleset.h"
	#include "trace.h"

	static struct landlock_hierarchy *
	get_hierarchy(const struct landlock_domain *const domain, const size_t layer)
	{
	struct landlock_hierarchy *hierarchy = domain->hierarchy;
	ssize_t i;

	if (WARN_ON_ONCE(layer >= domain->num_layers))
	return hierarchy;

	for (i = domain->num_layers - 1; i > layer; i--) {
	if (WARN_ON_ONCE(!hierarchy->parent))
	break;

	hierarchy = hierarchy->parent;
	}

	return hierarchy;
	}

	#ifdef CONFIG_SECURITY_LANDLOCK_KUNIT_TEST

	static void test_get_hierarchy(struct kunit *const test)
	{
	struct landlock_hierarchy dom0_hierarchy = {
	.id = 10,
	};
	struct landlock_hierarchy dom1_hierarchy = {
	.parent = &dom0_hierarchy,
	.id = 20,
	};
	struct landlock_hierarchy dom2_hierarchy = {
	.parent = &dom1_hierarchy,
	.id = 30,
	};
	struct landlock_domain dom2 = {
	.hierarchy = &dom2_hierarchy,
	.num_layers = 3,
	};

	KUNIT_EXPECT_EQ(test, 10, get_hierarchy(&dom2, 0)->id);
	KUNIT_EXPECT_EQ(test, 20, get_hierarchy(&dom2, 1)->id);
	KUNIT_EXPECT_EQ(test, 30, get_hierarchy(&dom2, 2)->id);
	/* KUNIT_EXPECT_EQ(test, 30, get_hierarchy(&dom2, -1)->id); */
	}

	#endif /* CONFIG_SECURITY_LANDLOCK_KUNIT_TEST */

	/* Get the youngest layer that denied the access_request. */
	static size_t get_denied_layer(const struct landlock_domain *const domain,
	access_mask_t *const access_request,
	const struct layer_masks *masks)
	{
	for (ssize_t i = ARRAY_SIZE(masks->layers) - 1; i >= 0; i--) {
	if (masks->layers[i].access & *access_request) {
	*access_request &= masks->layers[i].access;
	return i;
	}
	}

	/* Not found - fall back to default values */
	*access_request = 0;
	return domain->num_layers - 1;
	}

	#ifdef CONFIG_SECURITY_LANDLOCK_KUNIT_TEST

	static void test_get_denied_layer(struct kunit *const test)
	{
	const struct landlock_domain dom = {
	.num_layers = 5,
	};
	const struct layer_masks masks = {
	.layers[0].access = LANDLOCK_ACCESS_FS_EXECUTE \|
	LANDLOCK_ACCESS_FS_READ_DIR,
	.layers[1].access = LANDLOCK_ACCESS_FS_READ_FILE \|
	LANDLOCK_ACCESS_FS_READ_DIR,
	.layers[2].access = LANDLOCK_ACCESS_FS_REMOVE_DIR,
	};
	access_mask_t access;

	access = LANDLOCK_ACCESS_FS_EXECUTE;
	KUNIT_EXPECT_EQ(test, 0, get_denied_layer(&dom, &access, &masks));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_EXECUTE);

	access = LANDLOCK_ACCESS_FS_READ_FILE;
	KUNIT_EXPECT_EQ(test, 1, get_denied_layer(&dom, &access, &masks));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_READ_FILE);

	access = LANDLOCK_ACCESS_FS_READ_DIR;
	KUNIT_EXPECT_EQ(test, 1, get_denied_layer(&dom, &access, &masks));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_READ_DIR);

	access = LANDLOCK_ACCESS_FS_READ_FILE \| LANDLOCK_ACCESS_FS_READ_DIR;
	KUNIT_EXPECT_EQ(test, 1, get_denied_layer(&dom, &access, &masks));
	KUNIT_EXPECT_EQ(test, access,
	LANDLOCK_ACCESS_FS_READ_FILE \|
	LANDLOCK_ACCESS_FS_READ_DIR);

	access = LANDLOCK_ACCESS_FS_EXECUTE \| LANDLOCK_ACCESS_FS_READ_DIR;
	KUNIT_EXPECT_EQ(test, 1, get_denied_layer(&dom, &access, &masks));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_READ_DIR);

	access = LANDLOCK_ACCESS_FS_WRITE_FILE;
	KUNIT_EXPECT_EQ(test, 4, get_denied_layer(&dom, &access, &masks));
	KUNIT_EXPECT_EQ(test, access, 0);
	}

	#endif /* CONFIG_SECURITY_LANDLOCK_KUNIT_TEST */

	static size_t
	get_layer_from_deny_masks(access_mask_t *const access_request,
	const access_mask_t all_existing_optional_access,
	const deny_masks_t deny_masks,
	optional_access_t quiet_optional_accesses,
	bool *quiet)
	{
	const unsigned long access_opt = all_existing_optional_access;
	const unsigned long access_req = *access_request;
	access_mask_t missing = 0;
	size_t youngest_layer = 0;
	size_t access_index = 0;
	unsigned long access_bit;
	bool should_quiet = false;

	/* This will require change with new object types. */
	WARN_ON_ONCE(access_opt != _LANDLOCK_ACCESS_FS_OPTIONAL);

	for_each_set_bit(access_bit, &access_opt,
	BITS_PER_TYPE(access_mask_t)) {
	if (access_req & BIT(access_bit)) {
	const size_t layer =
	(deny_masks >>
	(access_index *
	HWEIGHT(LANDLOCK_MAX_NUM_LAYERS - 1))) &
	(LANDLOCK_MAX_NUM_LAYERS - 1);
	const bool layer_has_quiet =
	!!(quiet_optional_accesses & BIT(access_index));

	if (layer > youngest_layer) {
	youngest_layer = layer;
	missing = BIT(access_bit);
	should_quiet = layer_has_quiet;
	} else if (layer == youngest_layer) {
	missing \|= BIT(access_bit);
	/*
	* Whether the layer has rules with quiet flag
	* covering the file accessed does not depend on
	* the access, and so the following
	* WARN_ON_ONCE() should not fail.
	*/
	WARN_ON_ONCE(should_quiet && !layer_has_quiet);
	should_quiet = layer_has_quiet;
	}
	}
	access_index++;
	}

	*access_request = missing;
	*quiet = should_quiet;
	return youngest_layer;
	}

	#ifdef CONFIG_SECURITY_LANDLOCK_KUNIT_TEST

	static void test_get_layer_from_deny_masks(struct kunit *const test)
	{
	deny_masks_t deny_mask;
	access_mask_t access;
	optional_access_t quiet_optional_accesses;
	bool quiet;

	/* truncate:0 ioctl_dev:2 */
	deny_mask = 0x20;
	quiet_optional_accesses = 0;

	access = LANDLOCK_ACCESS_FS_TRUNCATE;
	KUNIT_EXPECT_EQ(test, 0,
	get_layer_from_deny_masks(
	&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
	deny_mask, quiet_optional_accesses, &quiet));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_TRUNCATE);
	KUNIT_EXPECT_EQ(test, quiet, false);

	access = LANDLOCK_ACCESS_FS_IOCTL_DEV;
	KUNIT_EXPECT_EQ(test, 2,
	get_layer_from_deny_masks(
	&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
	deny_mask, quiet_optional_accesses, &quiet));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_IOCTL_DEV);
	KUNIT_EXPECT_EQ(test, quiet, false);

	access = LANDLOCK_ACCESS_FS_TRUNCATE \| LANDLOCK_ACCESS_FS_IOCTL_DEV;
	KUNIT_EXPECT_EQ(test, 2,
	get_layer_from_deny_masks(
	&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
	deny_mask, quiet_optional_accesses, &quiet));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_IOCTL_DEV);
	KUNIT_EXPECT_EQ(test, quiet, false);

	/* layer denying truncate: quiet, ioctl: not quiet */
	quiet_optional_accesses = 0b01;

	access = LANDLOCK_ACCESS_FS_TRUNCATE;
	KUNIT_EXPECT_EQ(test, 0,
	get_layer_from_deny_masks(
	&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
	deny_mask, quiet_optional_accesses, &quiet));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_TRUNCATE);
	KUNIT_EXPECT_EQ(test, quiet, true);

	access = LANDLOCK_ACCESS_FS_IOCTL_DEV;
	KUNIT_EXPECT_EQ(test, 2,
	get_layer_from_deny_masks(
	&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
	deny_mask, quiet_optional_accesses, &quiet));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_IOCTL_DEV);
	KUNIT_EXPECT_EQ(test, quiet, false);

	access = LANDLOCK_ACCESS_FS_TRUNCATE \| LANDLOCK_ACCESS_FS_IOCTL_DEV;
	KUNIT_EXPECT_EQ(test, 2,
	get_layer_from_deny_masks(
	&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
	deny_mask, quiet_optional_accesses, &quiet));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_IOCTL_DEV);
	KUNIT_EXPECT_EQ(test, quiet, false);

	/* Reverse order - truncate:2 ioctl_dev:0 */
	deny_mask = 0x02;
	quiet_optional_accesses = 0;

	access = LANDLOCK_ACCESS_FS_TRUNCATE;
	KUNIT_EXPECT_EQ(test, 2,
	get_layer_from_deny_masks(
	&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
	deny_mask, quiet_optional_accesses, &quiet));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_TRUNCATE);
	KUNIT_EXPECT_EQ(test, quiet, false);

	access = LANDLOCK_ACCESS_FS_IOCTL_DEV;
	KUNIT_EXPECT_EQ(test, 0,
	get_layer_from_deny_masks(
	&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
	deny_mask, quiet_optional_accesses, &quiet));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_IOCTL_DEV);
	KUNIT_EXPECT_EQ(test, quiet, false);

	access = LANDLOCK_ACCESS_FS_TRUNCATE \| LANDLOCK_ACCESS_FS_IOCTL_DEV;
	KUNIT_EXPECT_EQ(test, 2,
	get_layer_from_deny_masks(
	&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
	deny_mask, quiet_optional_accesses, &quiet));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_TRUNCATE);
	KUNIT_EXPECT_EQ(test, quiet, false);

	/* layer denying truncate: quiet, ioctl: not quiet */
	quiet_optional_accesses = 0b01;

	access = LANDLOCK_ACCESS_FS_TRUNCATE;
	KUNIT_EXPECT_EQ(test, 2,
	get_layer_from_deny_masks(
	&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
	deny_mask, quiet_optional_accesses, &quiet));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_TRUNCATE);
	KUNIT_EXPECT_EQ(test, quiet, true);

	access = LANDLOCK_ACCESS_FS_IOCTL_DEV;
	KUNIT_EXPECT_EQ(test, 0,
	get_layer_from_deny_masks(
	&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
	deny_mask, quiet_optional_accesses, &quiet));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_IOCTL_DEV);
	KUNIT_EXPECT_EQ(test, quiet, false);

	access = LANDLOCK_ACCESS_FS_TRUNCATE \| LANDLOCK_ACCESS_FS_IOCTL_DEV;
	KUNIT_EXPECT_EQ(test, 2,
	get_layer_from_deny_masks(
	&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
	deny_mask, quiet_optional_accesses, &quiet));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_TRUNCATE);
	KUNIT_EXPECT_EQ(test, quiet, true);

	/* layer denying truncate: not quiet, ioctl: quiet */
	quiet_optional_accesses = 0b10;

	access = LANDLOCK_ACCESS_FS_TRUNCATE;
	KUNIT_EXPECT_EQ(test, 2,
	get_layer_from_deny_masks(
	&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
	deny_mask, quiet_optional_accesses, &quiet));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_TRUNCATE);
	KUNIT_EXPECT_EQ(test, quiet, false);

	access = LANDLOCK_ACCESS_FS_IOCTL_DEV;
	KUNIT_EXPECT_EQ(test, 0,
	get_layer_from_deny_masks(
	&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
	deny_mask, quiet_optional_accesses, &quiet));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_IOCTL_DEV);
	KUNIT_EXPECT_EQ(test, quiet, true);

	access = LANDLOCK_ACCESS_FS_TRUNCATE \| LANDLOCK_ACCESS_FS_IOCTL_DEV;
	KUNIT_EXPECT_EQ(test, 2,
	get_layer_from_deny_masks(
	&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
	deny_mask, quiet_optional_accesses, &quiet));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_TRUNCATE);
	KUNIT_EXPECT_EQ(test, quiet, false);

	/* truncate:15 ioctl_dev:15 */
	deny_mask = 0xff;
	quiet_optional_accesses = 0;

	access = LANDLOCK_ACCESS_FS_TRUNCATE;
	KUNIT_EXPECT_EQ(test, 15,
	get_layer_from_deny_masks(
	&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
	deny_mask, quiet_optional_accesses, &quiet));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_TRUNCATE);
	KUNIT_EXPECT_EQ(test, quiet, false);

	access = LANDLOCK_ACCESS_FS_TRUNCATE \| LANDLOCK_ACCESS_FS_IOCTL_DEV;
	KUNIT_EXPECT_EQ(test, 15,
	get_layer_from_deny_masks(
	&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
	deny_mask, quiet_optional_accesses, &quiet));
	KUNIT_EXPECT_EQ(test, access,
	LANDLOCK_ACCESS_FS_TRUNCATE \|
	LANDLOCK_ACCESS_FS_IOCTL_DEV);
	KUNIT_EXPECT_EQ(test, quiet, false);

	/* Both quiet (same layer so quietness must be the same) */
	quiet_optional_accesses = 0b11;

	access = LANDLOCK_ACCESS_FS_TRUNCATE;
	KUNIT_EXPECT_EQ(test, 15,
	get_layer_from_deny_masks(
	&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
	deny_mask, quiet_optional_accesses, &quiet));
	KUNIT_EXPECT_EQ(test, access, LANDLOCK_ACCESS_FS_TRUNCATE);
	KUNIT_EXPECT_EQ(test, quiet, true);

	access = LANDLOCK_ACCESS_FS_TRUNCATE \| LANDLOCK_ACCESS_FS_IOCTL_DEV;
	KUNIT_EXPECT_EQ(test, 15,
	get_layer_from_deny_masks(
	&access, _LANDLOCK_ACCESS_FS_OPTIONAL,
	deny_mask, quiet_optional_accesses, &quiet));
	KUNIT_EXPECT_EQ(test, access,
	LANDLOCK_ACCESS_FS_TRUNCATE \|
	LANDLOCK_ACCESS_FS_IOCTL_DEV);
	KUNIT_EXPECT_EQ(test, quiet, true);
	}

	#endif /* CONFIG_SECURITY_LANDLOCK_KUNIT_TEST */

	static bool is_valid_request(const struct landlock_request *const request)
	{
	if (WARN_ON_ONCE(request->layer_plus_one > LANDLOCK_MAX_NUM_LAYERS))
	return false;

	if (WARN_ON_ONCE(!(!!request->layer_plus_one ^ !!request->access)))
	return false;

	if (request->access) {
	if (WARN_ON_ONCE(!(!!request->layer_masks ^
	!!request->all_existing_optional_access)))
	return false;
	} else {
	if (WARN_ON_ONCE(request->layer_masks \|\|
	request->all_existing_optional_access))
	return false;
	}

	if (request->deny_masks) {
	if (WARN_ON_ONCE(!request->all_existing_optional_access))
	return false;
	static_assert(sizeof(request->all_existing_optional_access) ==
	sizeof(u32));
	if (WARN_ON_ONCE(
	request->quiet_optional_accesses >=
	BIT(hweight32(
	request->all_existing_optional_access))))
	return false;
	}

	return true;
	}

	static access_mask_t
	pick_access_mask_for_request_type(const enum landlock_request_type type,
	const struct access_masks access_masks)
	{
	switch (type) {
	case LANDLOCK_REQUEST_FS_ACCESS:
	return access_masks.fs;
	case LANDLOCK_REQUEST_NET_ACCESS:
	return access_masks.net;
	default:
	WARN_ONCE(1, "Invalid request type %d passed to %s", type,
	__func__);
	return 0;
	}
	}

	/*
	* Whether a quiet rule silences the denial: the rule must cover the whole
	* denied access in the layer that denied it (a quiet rule in a non-denying
	* layer does not suppress the denial).
	*/
	static bool
	is_denial_quieted(const struct landlock_request *const request,
	const struct landlock_hierarchy *const youngest_denied,
	const access_mask_t missing, const bool object_quiet_flag)
	{
	if (object_quiet_flag) {
	const access_mask_t quiet_mask =
	pick_access_mask_for_request_type(
	request->type, youngest_denied->quiet_masks);

	return (quiet_mask & missing) == missing;
	}

	/*
	* Either the object is not quiet, or this is a scope request. We check
	* request->type to distinguish between the two cases.
	*/
	switch (request->type) {
	case LANDLOCK_REQUEST_SCOPE_SIGNAL:
	return !!(youngest_denied->quiet_masks.scope &
	LANDLOCK_SCOPE_SIGNAL);
	case LANDLOCK_REQUEST_SCOPE_ABSTRACT_UNIX_SOCKET:
	return !!(youngest_denied->quiet_masks.scope &
	LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET);
	/*
	* Leave LANDLOCK_REQUEST_PTRACE and LANDLOCK_REQUEST_FS_CHANGE_TOPOLOGY
	* unhandled for now - they are never quiet.
	*/
	default:
	return false;
	}
	}

	/*
	* Computes whether a denial from youngest_denied is selected for logging by the
	* domain's policy: its logging must not be disabled (by both per-execution
	* flags being off, or by an ancestor's
	* LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF), the per-execution flag matching
	* same_exec must be set, and no quiet rule may cover the denied access.
	* landlock_log_denial() computes this once and passes it to
	* landlock_audit_denial(), which additionally requires audit_enabled.
	*/
	static bool
	is_denial_logged(const struct landlock_request *const request,
	const struct landlock_hierarchy *const youngest_denied,
	const access_mask_t missing, const bool same_exec,
	const bool object_quiet_flag)
	{
	if (READ_ONCE(youngest_denied->log_status) == LANDLOCK_LOG_DISABLED)
	return false;

	if (!(same_exec ? youngest_denied->log_same_exec :
	youngest_denied->log_new_exec))
	return false;

	return !is_denial_quieted(request, youngest_denied, missing,
	object_quiet_flag);
	}

	/**
	* landlock_log_denial - Log a denied access
	*
	* @subject: The Landlock subject's credential denying an action.
	* @request: Detail of the user space request.
	*/
	void landlock_log_denial(const struct landlock_cred_security *const subject,
	const struct landlock_request *const request)
	{
	struct landlock_hierarchy *youngest_denied;
	size_t youngest_layer;
	access_mask_t missing;
	bool object_quiet_flag = false;

	if (WARN_ON_ONCE(!subject \|\| !subject->domain \|\|
	!subject->domain->hierarchy \|\| !request))
	return;

	if (!is_valid_request(request))
	return;

	missing = request->access;
	if (missing) {
	/* Gets the nearest domain that denies the request. */
	if (request->layer_masks) {
	youngest_layer = get_denied_layer(subject->domain,
	&missing,
	request->layer_masks);
	object_quiet_flag =
	request->layer_masks->layers[youngest_layer]
	.quiet;
	} else {
	youngest_layer = get_layer_from_deny_masks(
	&missing, _LANDLOCK_ACCESS_FS_OPTIONAL,
	request->deny_masks,
	request->quiet_optional_accesses,
	&object_quiet_flag);
	}
	youngest_denied =
	get_hierarchy(subject->domain, youngest_layer);
	} else {
	youngest_layer = request->layer_plus_one - 1;
	youngest_denied =
	get_hierarchy(subject->domain, youngest_layer);
	}

	const bool same_exec = !!(subject->domain_exec & BIT(youngest_layer));
	const bool logged = is_denial_logged(request, youngest_denied, missing,
	same_exec, object_quiet_flag);

	/*
	* Consistently keeps track of the number of denied access requests even
	* if audit is currently disabled, or if audit rules currently exclude
	* this record type, or if landlock_restrict_self(2)'s flags quiet logs.
	*/
	atomic64_inc(&youngest_denied->num_denials);

	landlock_trace_denial(request, youngest_denied, missing, same_exec,
	logged);
	landlock_audit_denial(request, youngest_denied, missing, logged);
	}

	/**
	* landlock_log_free_domain - Log domain deallocation
	*
	* @hierarchy: The domain's hierarchy being deallocated.
	*
	* Called from landlock_put_domain_deferred() (via a work queue scheduled by
	* hook_cred_free()) or directly from landlock_put_domain().
	*/
	void landlock_log_free_domain(const struct landlock_hierarchy *const hierarchy)
	{
	if (WARN_ON_ONCE(!hierarchy))
	return;

	landlock_trace_free_domain(hierarchy);
	landlock_audit_free_domain(hierarchy);
	}

	#ifdef CONFIG_SECURITY_LANDLOCK_KUNIT_TEST

	static struct kunit_case test_cases[] = {
	/* clang-format off */
	KUNIT_CASE(test_get_hierarchy),
	KUNIT_CASE(test_get_denied_layer),
	KUNIT_CASE(test_get_layer_from_deny_masks),
	{}
	/* clang-format on */
	};

	static struct kunit_suite test_suite = {
	.name = "landlock_log",
	.test_cases = test_cases,
	};

	kunit_test_suite(test_suite);

	#endif /* CONFIG_SECURITY_LANDLOCK_KUNIT_TEST */