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-rw-r--r--security/landlock/domain.c775
1 files changed, 775 insertions, 0 deletions
diff --git a/security/landlock/domain.c b/security/landlock/domain.c
new file mode 100644
index 000000000..93c7104fd
--- /dev/null
+++ b/security/landlock/domain.c
@@ -0,0 +1,775 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Landlock - Domain management
+ *
+ * Copyright © 2016-2020 Mickaël Salaün <mic@digikod.net>
+ * Copyright © 2018-2020 ANSSI
+ * Copyright © 2024-2025 Microsoft Corporation
+ * Copyright © 2026 Cloudflare, Inc.
+ */
+
+#include <kunit/test.h>
+#include <linux/bitops.h>
+#include <linux/bits.h>
+#include <linux/cleanup.h>
+#include <linux/cred.h>
+#include <linux/err.h>
+#include <linux/file.h>
+#include <linux/lockdep.h>
+#include <linux/mm.h>
+#include <linux/mutex.h>
+#include <linux/overflow.h>
+#include <linux/path.h>
+#include <linux/pid.h>
+#include <linux/rbtree.h>
+#include <linux/refcount.h>
+#include <linux/sched.h>
+#include <linux/signal.h>
+#include <linux/slab.h>
+#include <linux/uidgid.h>
+#include <linux/workqueue.h>
+
+#include "access.h"
+#include "common.h"
+#include "domain.h"
+#include "id.h"
+#include "limits.h"
+#include "ruleset.h"
+
+static void build_check_domain(void)
+{
+ const struct landlock_domain domain = {
+ .num_layers = ~0,
+ };
+
+ BUILD_BUG_ON(domain.num_layers < LANDLOCK_MAX_NUM_LAYERS);
+}
+
+static struct landlock_domain *create_domain(const u32 num_layers)
+{
+ struct landlock_domain *new_domain;
+
+ build_check_domain();
+ new_domain = kzalloc_flex(*new_domain, handled_masks, num_layers,
+ GFP_KERNEL_ACCOUNT);
+ if (!new_domain)
+ return ERR_PTR(-ENOMEM);
+
+ refcount_set(&new_domain->usage, 1);
+ new_domain->rules.root_inode = RB_ROOT;
+
+#if IS_ENABLED(CONFIG_INET)
+ new_domain->rules.root_net_port = RB_ROOT;
+#endif /* IS_ENABLED(CONFIG_INET) */
+
+ new_domain->num_layers = num_layers;
+ return new_domain;
+}
+
+static void free_domain(struct landlock_domain *const domain)
+{
+ might_sleep();
+ landlock_free_rules(&domain->rules);
+ landlock_put_hierarchy(domain->hierarchy);
+ kfree(domain);
+}
+
+void landlock_put_domain(struct landlock_domain *const domain)
+{
+ might_sleep();
+ if (domain && refcount_dec_and_test(&domain->usage))
+ free_domain(domain);
+}
+
+static void free_domain_work(struct work_struct *const work)
+{
+ struct landlock_domain *domain;
+
+ domain = container_of(work, struct landlock_domain, work_free);
+ free_domain(domain);
+}
+
+void landlock_put_domain_deferred(struct landlock_domain *const domain)
+{
+ if (domain && refcount_dec_and_test(&domain->usage)) {
+ INIT_WORK(&domain->work_free, free_domain_work);
+ schedule_work(&domain->work_free);
+ }
+}
+
+/* The returned access has the same lifetime as the domain. */
+static const struct landlock_rule *
+find_rule(const struct landlock_domain *const domain,
+ const struct landlock_id id)
+{
+ const struct rb_root *root;
+ const struct rb_node *node;
+
+ root = landlock_get_rule_root((struct landlock_rules *)&domain->rules,
+ id.type);
+ if (IS_ERR(root))
+ return NULL;
+ node = root->rb_node;
+
+ while (node) {
+ struct landlock_rule *this =
+ rb_entry(node, struct landlock_rule, node);
+
+ if (this->key.data == id.key.data)
+ return this;
+ if (this->key.data < id.key.data)
+ node = node->rb_right;
+ else
+ node = node->rb_left;
+ }
+ return NULL;
+}
+
+/**
+ * landlock_unmask_layers - Remove the access rights in @masks which are
+ * granted by a matching rule
+ *
+ * Looks up the rule matching @id in @domain, then updates the set of
+ * (per-layer) unfulfilled access rights @masks so that all the access rights
+ * granted by that rule are removed (because they are now fulfilled).
+ *
+ * @domain: The Landlock domain to search for a matching rule.
+ * @id: Identifier for the rule target (e.g. inode, port).
+ * @masks: A matrix of unfulfilled access rights for each layer.
+ * @matched_rule: Optional output for the matched rule (for tracing); set to
+ * the matching rule when non-NULL, unchanged otherwise.
+ *
+ * Return: True if the request is allowed (i.e. the access rights granted all
+ * remaining unfulfilled access rights and masks has no leftover set bits).
+ */
+bool landlock_unmask_layers(const struct landlock_domain *const domain,
+ const struct landlock_id id,
+ struct layer_masks *masks,
+ const struct landlock_rule **matched_rule)
+{
+ const struct landlock_rule *rule;
+
+ if (!masks)
+ return true;
+
+ rule = find_rule(domain, id);
+ if (!rule)
+ return false;
+
+ if (matched_rule)
+ *matched_rule = rule;
+
+ /*
+ * An access is granted if, for each policy layer, at least one rule
+ * encountered on the pathwalk grants the requested access, regardless
+ * of its position in the layer stack. We must then check the remaining
+ * layers for each inode, from the first added layer to the last one.
+ * When there are multiple requested accesses, for each policy layer,
+ * the full set of requested accesses may not be granted by only one
+ * rule, but by the union (binary OR) of multiple rules. For example,
+ * /a/b <execute> + /a <read> grants /a/b <execute + read>.
+ *
+ * This function is called once per matching rule during the pathwalk,
+ * progressively clearing bits in @masks. The overall access decision
+ * is per-layer: access is granted iff masks->layers[l].access == 0 for
+ * all layers l. When two independent mechanisms can each grant access
+ * within a layer (e.g. a path rule OR a scope exception), the
+ * composition must evaluate per-layer: FOR-ALL l (A(l) OR B(l)), not
+ * (FOR-ALL l A(l)) OR (FOR-ALL l B(l)), to prevent bypass when
+ * different layers grant via different mechanisms.
+ */
+ for (size_t i = 0; i < rule->num_layers; i++) {
+ const struct landlock_layer *const layer = &rule->layers[i];
+
+ /* Clear the bits where the layer in the rule grants access. */
+ masks->layers[layer->level - 1].access &= ~layer->access;
+
+#ifdef CONFIG_SECURITY_LANDLOCK_LOG
+ /* Collect rule flags for each layer. */
+ if (layer->flags.quiet)
+ masks->layers[layer->level - 1].quiet = true;
+#endif /* CONFIG_SECURITY_LANDLOCK_LOG */
+ }
+
+ for (size_t i = 0; i < ARRAY_SIZE(masks->layers); i++) {
+ if (masks->layers[i].access)
+ return false;
+ }
+ return true;
+}
+
+typedef access_mask_t
+get_access_mask_t(const struct landlock_domain *const domain,
+ const u16 layer_level);
+
+/**
+ * landlock_init_layer_masks - Initialize layer masks from an access request
+ *
+ * Populates @masks such that for each access right in @access_request, the bits
+ * for all the layers are set where this access right is handled. Rule flags
+ * are also zeroed.
+ *
+ * @domain: The domain that defines the current restrictions.
+ * @access_request: The requested access rights to check.
+ * @masks: Layer access masks to populate.
+ * @key_type: The key type to switch between access masks of different types.
+ *
+ * Return: An access mask where each access right bit is set which is handled in
+ * any of the active layers in @domain.
+ */
+access_mask_t
+landlock_init_layer_masks(const struct landlock_domain *const domain,
+ const access_mask_t access_request,
+ struct layer_masks *const masks,
+ const enum landlock_key_type key_type)
+{
+ access_mask_t handled_accesses = 0;
+ get_access_mask_t *get_access_mask;
+
+ switch (key_type) {
+ case LANDLOCK_KEY_INODE:
+ get_access_mask = landlock_get_fs_access_mask;
+ break;
+
+#if IS_ENABLED(CONFIG_INET)
+ case LANDLOCK_KEY_NET_PORT:
+ get_access_mask = landlock_get_net_access_mask;
+ break;
+#endif /* IS_ENABLED(CONFIG_INET) */
+
+ default:
+ WARN_ON_ONCE(1);
+ return 0;
+ }
+
+ /* An empty access request can happen because of O_WRONLY | O_RDWR. */
+ if (!access_request)
+ return 0;
+
+ for (size_t i = 0; i < domain->num_layers; i++) {
+ const access_mask_t handled = get_access_mask(domain, i);
+
+ masks->layers[i].access = access_request & handled;
+ handled_accesses |= masks->layers[i].access;
+#ifdef CONFIG_SECURITY_LANDLOCK_LOG
+ masks->layers[i].quiet = false;
+#endif /* CONFIG_SECURITY_LANDLOCK_LOG */
+ }
+ for (size_t i = domain->num_layers; i < ARRAY_SIZE(masks->layers);
+ i++) {
+ masks->layers[i].access = 0;
+#ifdef CONFIG_SECURITY_LANDLOCK_LOG
+ masks->layers[i].quiet = false;
+#endif /* CONFIG_SECURITY_LANDLOCK_LOG */
+ }
+
+ return handled_accesses;
+}
+
+static int merge_tree(struct landlock_domain *const dst,
+ struct landlock_ruleset *const src,
+ const enum landlock_key_type key_type)
+{
+ struct landlock_rule *walker_rule, *next_rule;
+ struct rb_root *src_root;
+ int err = 0;
+
+ might_sleep();
+ lockdep_assert_held(&src->lock);
+
+ src_root = landlock_get_rule_root(&src->rules, key_type);
+ if (IS_ERR(src_root))
+ return PTR_ERR(src_root);
+
+ /* Merges the @src tree. */
+ rbtree_postorder_for_each_entry_safe(walker_rule, next_rule, src_root,
+ node) {
+ struct landlock_layer layers[] = { {
+ .level = dst->num_layers,
+ } };
+ const struct landlock_id id = {
+ .key = walker_rule->key,
+ .type = key_type,
+ };
+
+ if (WARN_ON_ONCE(walker_rule->num_layers != 1))
+ return -EINVAL;
+
+ if (WARN_ON_ONCE(walker_rule->layers[0].level != 0))
+ return -EINVAL;
+
+ layers[0].access = walker_rule->layers[0].access;
+ layers[0].flags = walker_rule->layers[0].flags;
+
+ err = landlock_store_rule(&dst->rules, id, &layers,
+ ARRAY_SIZE(layers));
+ if (err)
+ return err;
+ }
+ return err;
+}
+
+static int merge_ruleset(struct landlock_domain *const dst,
+ struct landlock_ruleset *const src)
+{
+ int err = 0;
+
+ might_sleep();
+ /* Should already be checked by landlock_merge_ruleset() */
+ if (WARN_ON_ONCE(!src))
+ return 0;
+ /* Only merge into a domain. */
+ if (WARN_ON_ONCE(!dst || !dst->hierarchy))
+ return -EINVAL;
+
+ lockdep_assert_held(&src->lock);
+
+ /* Stacks the new layer. */
+ if (WARN_ON_ONCE(dst->num_layers < 1))
+ return -EINVAL;
+
+ dst->handled_masks[dst->num_layers - 1] =
+ landlock_upgrade_handled_access_masks(src->handled_masks);
+
+ /* Merges the @src inode tree. */
+ err = merge_tree(dst, src, LANDLOCK_KEY_INODE);
+ if (err)
+ return err;
+
+#if IS_ENABLED(CONFIG_INET)
+ /* Merges the @src network port tree. */
+ err = merge_tree(dst, src, LANDLOCK_KEY_NET_PORT);
+ if (err)
+ return err;
+#endif /* IS_ENABLED(CONFIG_INET) */
+
+ return 0;
+}
+
+static int inherit_tree(struct landlock_domain *const parent,
+ struct landlock_domain *const child,
+ const enum landlock_key_type key_type)
+{
+ struct landlock_rule *walker_rule, *next_rule;
+ struct rb_root *parent_root;
+ int err = 0;
+
+ might_sleep();
+
+ parent_root = landlock_get_rule_root(&parent->rules, key_type);
+ if (IS_ERR(parent_root))
+ return PTR_ERR(parent_root);
+
+ /* Copies the @parent inode or network tree. */
+ rbtree_postorder_for_each_entry_safe(walker_rule, next_rule,
+ parent_root, node) {
+ const struct landlock_id id = {
+ .key = walker_rule->key,
+ .type = key_type,
+ };
+
+ err = landlock_store_rule(&child->rules, id,
+ &walker_rule->layers,
+ walker_rule->num_layers);
+ if (err)
+ return err;
+ }
+ return err;
+}
+
+static int inherit_ruleset(struct landlock_domain *const parent,
+ struct landlock_domain *const child)
+{
+ int err = 0;
+
+ might_sleep();
+ if (!parent)
+ return 0;
+
+ /* Copies the @parent inode tree. */
+ err = inherit_tree(parent, child, LANDLOCK_KEY_INODE);
+ if (err)
+ return err;
+
+#if IS_ENABLED(CONFIG_INET)
+ /* Copies the @parent network port tree. */
+ err = inherit_tree(parent, child, LANDLOCK_KEY_NET_PORT);
+ if (err)
+ return err;
+#endif /* IS_ENABLED(CONFIG_INET) */
+
+ if (WARN_ON_ONCE(child->num_layers <= parent->num_layers))
+ return -EINVAL;
+
+ /*
+ * Copies the parent layer stack and leaves a space for the new layer.
+ */
+ memcpy(child->handled_masks, parent->handled_masks,
+ flex_array_size(parent, handled_masks, parent->num_layers));
+
+ if (WARN_ON_ONCE(!parent->hierarchy))
+ return -EINVAL;
+
+ landlock_get_hierarchy(parent->hierarchy);
+ child->hierarchy->parent = parent->hierarchy;
+
+ return 0;
+}
+
+/**
+ * landlock_merge_ruleset - Merge a ruleset with a domain
+ *
+ * @parent: Parent domain.
+ * @ruleset: New ruleset to be merged.
+ *
+ * The current task is requesting to be restricted. The subjective credentials
+ * must not be in an overridden state. cf. landlock_init_hierarchy_log().
+ *
+ * The caller must hold @ruleset->lock.
+ *
+ * Return: A new domain merging @parent and @ruleset on success, or ERR_PTR() on
+ * failure. If @parent is NULL, the new domain duplicates @ruleset.
+ */
+struct landlock_domain *
+landlock_merge_ruleset(struct landlock_domain *const parent,
+ struct landlock_ruleset *const ruleset)
+{
+ struct landlock_domain *new_dom __free(landlock_put_domain) = NULL;
+ u32 num_layers;
+ int err;
+
+ might_sleep();
+ lockdep_assert_held(&ruleset->lock);
+ if (WARN_ON_ONCE(!ruleset))
+ return ERR_PTR(-EINVAL);
+
+ if (parent) {
+ if (parent->num_layers >= LANDLOCK_MAX_NUM_LAYERS)
+ return ERR_PTR(-E2BIG);
+ num_layers = parent->num_layers + 1;
+ } else {
+ num_layers = 1;
+ }
+
+ /* Creates a new domain... */
+ new_dom = create_domain(num_layers);
+ if (IS_ERR(new_dom))
+ return new_dom;
+
+ new_dom->hierarchy =
+ kzalloc_obj(*new_dom->hierarchy, GFP_KERNEL_ACCOUNT);
+ if (!new_dom->hierarchy)
+ return ERR_PTR(-ENOMEM);
+
+ refcount_set(&new_dom->hierarchy->usage, 1);
+
+ /* ...as a child of @parent... */
+ err = inherit_ruleset(parent, new_dom);
+ if (err)
+ return ERR_PTR(err);
+
+ /* ...and including @ruleset. */
+ err = merge_ruleset(new_dom, ruleset);
+ if (err)
+ return ERR_PTR(err);
+
+ err = landlock_init_hierarchy_log(new_dom->hierarchy);
+ if (err)
+ return ERR_PTR(err);
+
+#ifdef CONFIG_SECURITY_LANDLOCK_LOG
+ new_dom->hierarchy->quiet_masks = ruleset->quiet_masks;
+#endif /* CONFIG_SECURITY_LANDLOCK_LOG */
+
+ return no_free_ptr(new_dom);
+}
+
+#ifdef CONFIG_SECURITY_LANDLOCK_LOG
+
+/**
+ * get_current_exe - Get the current's executable path, if any
+ *
+ * @exe_str: Returned pointer to a path string with a lifetime tied to the
+ * returned buffer, if any.
+ * @exe_size: Returned size of @exe_str (including the trailing null
+ * character), if any.
+ *
+ * Return: A pointer to an allocated buffer where @exe_str point to, %NULL if
+ * there is no executable path, or an error otherwise.
+ */
+static const void *get_current_exe(const char **const exe_str,
+ size_t *const exe_size)
+{
+ const size_t buffer_size = LANDLOCK_PATH_MAX_SIZE;
+ struct mm_struct *mm = current->mm;
+ struct file *file __free(fput) = NULL;
+ char *buffer __free(kfree) = NULL;
+ const char *exe;
+ ssize_t size;
+
+ if (!mm)
+ return NULL;
+
+ file = get_mm_exe_file(mm);
+ if (!file)
+ return NULL;
+
+ buffer = kmalloc(buffer_size, GFP_KERNEL);
+ if (!buffer)
+ return ERR_PTR(-ENOMEM);
+
+ exe = d_path(&file->f_path, buffer, buffer_size);
+ if (WARN_ON_ONCE(IS_ERR(exe)))
+ /* Should never happen according to LANDLOCK_PATH_MAX_SIZE. */
+ return ERR_CAST(exe);
+
+ size = buffer + buffer_size - exe;
+ if (WARN_ON_ONCE(size <= 0))
+ return ERR_PTR(-ENAMETOOLONG);
+
+ *exe_size = size;
+ *exe_str = exe;
+ return no_free_ptr(buffer);
+}
+
+/*
+ * Return: A newly allocated object describing a domain, or an error
+ * otherwise.
+ */
+static struct landlock_details *get_current_details(void)
+{
+ /* Cf. audit_log_d_path_exe() */
+ static const char null_path[] = "(null)";
+ const char *path_str = null_path;
+ size_t path_size = sizeof(null_path);
+ const void *buffer __free(kfree) = NULL;
+ struct landlock_details *details;
+
+ buffer = get_current_exe(&path_str, &path_size);
+ if (IS_ERR(buffer))
+ return ERR_CAST(buffer);
+
+ /*
+ * Create the new details according to the path's length. Account to
+ * the calling task's memcg, like the other Landlock per-domain
+ * allocations, even if it may not control the related size.
+ */
+ details =
+ kzalloc_flex(*details, exe_path, path_size, GFP_KERNEL_ACCOUNT);
+ if (!details)
+ return ERR_PTR(-ENOMEM);
+
+ memcpy(details->exe_path, path_str, path_size);
+ details->pid = get_pid(task_tgid(current));
+ details->uid = from_kuid(&init_user_ns, current_uid());
+ get_task_comm(details->comm, current);
+ return details;
+}
+
+/**
+ * landlock_init_hierarchy_log - Partially initialize landlock_hierarchy
+ *
+ * @hierarchy: The hierarchy to initialize.
+ *
+ * The current task is referenced as the domain that is enforcing the
+ * restriction. The subjective credentials must not be in an overridden state.
+ *
+ * @hierarchy->parent and @hierarchy->usage should already be set.
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+int landlock_init_hierarchy_log(struct landlock_hierarchy *const hierarchy)
+{
+ struct landlock_details *details;
+
+ details = get_current_details();
+ if (IS_ERR(details))
+ return PTR_ERR(details);
+
+ hierarchy->details = details;
+ hierarchy->id = landlock_get_id_range(1);
+ /*
+ * The hierarchy is born unobservable: landlock_restrict_self() moves it
+ * out of LANDLOCK_LOG_UNCOMMITTED once it has emitted the creation
+ * event, so the matching free_domain event fires for it and not for a
+ * hierarchy whose creation was never observed.
+ */
+ hierarchy->log_status = LANDLOCK_LOG_UNCOMMITTED;
+ hierarchy->log_same_exec = true;
+ hierarchy->log_new_exec = false;
+ atomic64_set(&hierarchy->num_denials, 0);
+ return 0;
+}
+
+static deny_masks_t
+get_layer_deny_mask(const access_mask_t all_existing_optional_access,
+ const unsigned long access_bit, const size_t layer)
+{
+ unsigned long access_weight;
+
+ /* This may require change with new object types. */
+ WARN_ON_ONCE(all_existing_optional_access !=
+ _LANDLOCK_ACCESS_FS_OPTIONAL);
+
+ if (WARN_ON_ONCE(layer >= LANDLOCK_MAX_NUM_LAYERS))
+ return 0;
+
+ access_weight = hweight_long(all_existing_optional_access &
+ GENMASK(access_bit, 0));
+ if (WARN_ON_ONCE(access_weight < 1))
+ return 0;
+
+ return layer
+ << ((access_weight - 1) * HWEIGHT(LANDLOCK_MAX_NUM_LAYERS - 1));
+}
+
+/**
+ * landlock_get_quiet_optional_accesses - Get optional accesses which are
+ * covered by quiet rule flags.
+ *
+ * @all_existing_optional_access: Bitmask of valid optional accesses.
+ * @deny_masks: Domain layer levels that denied each optional access (the
+ * deny_masks field on struct landlock_file_security).
+ * @masks: The struct layer_masks collected during the path walk.
+ *
+ * Return: a bitmask of which optional accesses are denied by layers for which
+ * the quiet flag was collected during the path walk.
+ */
+optional_access_t landlock_get_quiet_optional_accesses(
+ const access_mask_t all_existing_optional_access,
+ const deny_masks_t deny_masks, const struct layer_masks *const masks)
+{
+ const unsigned long access_opt = all_existing_optional_access;
+ size_t access_index = 0;
+ unsigned long access_bit;
+ optional_access_t quiet_optional_accesses = 0;
+
+ /* 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)) {
+ const u8 layer =
+ (deny_masks >> (access_index *
+ HWEIGHT(LANDLOCK_MAX_NUM_LAYERS - 1))) &
+ (LANDLOCK_MAX_NUM_LAYERS - 1);
+
+ if (masks->layers[layer].quiet)
+ quiet_optional_accesses |= BIT(access_index);
+ access_index++;
+ }
+ return quiet_optional_accesses;
+}
+
+#ifdef CONFIG_SECURITY_LANDLOCK_KUNIT_TEST
+
+static void test_get_layer_deny_mask(struct kunit *const test)
+{
+ const unsigned long truncate = BIT_INDEX(LANDLOCK_ACCESS_FS_TRUNCATE);
+ const unsigned long ioctl_dev = BIT_INDEX(LANDLOCK_ACCESS_FS_IOCTL_DEV);
+
+ KUNIT_EXPECT_EQ(test, 0,
+ get_layer_deny_mask(_LANDLOCK_ACCESS_FS_OPTIONAL,
+ truncate, 0));
+ KUNIT_EXPECT_EQ(test, 0x3,
+ get_layer_deny_mask(_LANDLOCK_ACCESS_FS_OPTIONAL,
+ truncate, 3));
+
+ KUNIT_EXPECT_EQ(test, 0,
+ get_layer_deny_mask(_LANDLOCK_ACCESS_FS_OPTIONAL,
+ ioctl_dev, 0));
+ KUNIT_EXPECT_EQ(test, 0xf0,
+ get_layer_deny_mask(_LANDLOCK_ACCESS_FS_OPTIONAL,
+ ioctl_dev, 15));
+}
+
+#endif /* CONFIG_SECURITY_LANDLOCK_KUNIT_TEST */
+
+deny_masks_t
+landlock_get_deny_masks(const access_mask_t all_existing_optional_access,
+ const access_mask_t optional_access,
+ const struct layer_masks *const masks)
+{
+ const unsigned long access_opt = optional_access;
+ unsigned long access_bit;
+ deny_masks_t deny_masks = 0;
+ access_mask_t all_denied = 0;
+
+ /* This may require change with new object types. */
+ WARN_ON_ONCE(!access_mask_subset(optional_access,
+ all_existing_optional_access));
+
+ if (WARN_ON_ONCE(!masks))
+ return 0;
+
+ if (WARN_ON_ONCE(!access_opt))
+ return 0;
+
+ for (ssize_t i = ARRAY_SIZE(masks->layers) - 1; i >= 0; i--) {
+ const access_mask_t denied = masks->layers[i].access &
+ optional_access;
+ const unsigned long newly_denied = denied & ~all_denied;
+
+ if (!newly_denied)
+ continue;
+
+ for_each_set_bit(access_bit, &newly_denied,
+ 8 * sizeof(access_mask_t)) {
+ deny_masks |= get_layer_deny_mask(
+ all_existing_optional_access, access_bit, i);
+ }
+ all_denied |= denied;
+ }
+ return deny_masks;
+}
+
+#ifdef CONFIG_SECURITY_LANDLOCK_KUNIT_TEST
+
+static void test_landlock_get_deny_masks(struct kunit *const test)
+{
+ const struct layer_masks layers1 = {
+ .layers[0].access = LANDLOCK_ACCESS_FS_EXECUTE |
+ LANDLOCK_ACCESS_FS_IOCTL_DEV,
+ .layers[1].access = LANDLOCK_ACCESS_FS_TRUNCATE,
+ .layers[2].access = LANDLOCK_ACCESS_FS_IOCTL_DEV,
+ .layers[9].access = LANDLOCK_ACCESS_FS_EXECUTE,
+ };
+
+ KUNIT_EXPECT_EQ(test, 0x1,
+ landlock_get_deny_masks(_LANDLOCK_ACCESS_FS_OPTIONAL,
+ LANDLOCK_ACCESS_FS_TRUNCATE,
+ &layers1));
+ KUNIT_EXPECT_EQ(test, 0x20,
+ landlock_get_deny_masks(_LANDLOCK_ACCESS_FS_OPTIONAL,
+ LANDLOCK_ACCESS_FS_IOCTL_DEV,
+ &layers1));
+ KUNIT_EXPECT_EQ(
+ test, 0x21,
+ landlock_get_deny_masks(_LANDLOCK_ACCESS_FS_OPTIONAL,
+ LANDLOCK_ACCESS_FS_TRUNCATE |
+ LANDLOCK_ACCESS_FS_IOCTL_DEV,
+ &layers1));
+}
+
+#endif /* CONFIG_SECURITY_LANDLOCK_KUNIT_TEST */
+
+#ifdef CONFIG_SECURITY_LANDLOCK_KUNIT_TEST
+
+static struct kunit_case test_cases[] = {
+ /* clang-format off */
+ KUNIT_CASE(test_get_layer_deny_mask),
+ KUNIT_CASE(test_landlock_get_deny_masks),
+ {}
+ /* clang-format on */
+};
+
+static struct kunit_suite test_suite = {
+ .name = "landlock_domain",
+ .test_cases = test_cases,
+};
+
+kunit_test_suite(test_suite);
+
+#endif /* CONFIG_SECURITY_LANDLOCK_KUNIT_TEST */
+
+#endif /* CONFIG_SECURITY_LANDLOCK_LOG */