You can improve the subject with: "landlock: Refactor unmask_layers()
and init_layer_masks()"
On 29/08/2022 19:03, Konstantin Meskhidze wrote:
Adds new key_type argument to init_layer_masks() helper functions.
This modification supports implementing new rule types in the next
Landlock versions.
Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@xxxxxxxxxx>
As for patch 2/18, you can append:
Co-developed-by: Mickaël Salaün <mic@xxxxxxxxxxx>
---
Changes since v6:
* Removes masks_size attribute from init_layer_masks().
* Refactors init_layer_masks() with new landlock_key_type.
Changes since v5:
* Splits commit.
* Formats code with clang-format-14.
Changes since v4:
* Refactors init_layer_masks(), get_handled_accesses()
and unmask_layers() functions to support multiple rule types.
* Refactors landlock_get_fs_access_mask() function with
LANDLOCK_MASK_ACCESS_FS mask.
Changes since v3:
* Splits commit.
* Refactors landlock_unmask_layers functions.
---
security/landlock/fs.c | 33 +++++++++++++++++-----------
security/landlock/ruleset.c | 44 +++++++++++++++++++++++++++----------
security/landlock/ruleset.h | 11 +++++-----
3 files changed, 58 insertions(+), 30 deletions(-)
diff --git a/security/landlock/fs.c b/security/landlock/fs.c
index b03d6153f628..a4d9aea539cd 100644
--- a/security/landlock/fs.c
+++ b/security/landlock/fs.c
@@ -439,16 +439,20 @@ static int check_access_path_dual(
if (unlikely(dentry_child1)) {
unmask_layers(find_rule(domain, dentry_child1),
init_layer_masks(domain, LANDLOCK_MASK_ACCESS_FS,
- &_layer_masks_child1),
- &_layer_masks_child1);
+ &_layer_masks_child1,
+ LANDLOCK_KEY_INODE),
+ &_layer_masks_child1,
+ ARRAY_SIZE(_layer_masks_child1));
layer_masks_child1 = &_layer_masks_child1;
child1_is_directory = d_is_dir(dentry_child1);
}
if (unlikely(dentry_child2)) {
unmask_layers(find_rule(domain, dentry_child2),
init_layer_masks(domain, LANDLOCK_MASK_ACCESS_FS,
- &_layer_masks_child2),
- &_layer_masks_child2);
+ &_layer_masks_child2,
+ LANDLOCK_KEY_INODE),
+ &_layer_masks_child2,
+ ARRAY_SIZE(_layer_masks_child2));
layer_masks_child2 = &_layer_masks_child2;
child2_is_directory = d_is_dir(dentry_child2);
}
@@ -500,15 +504,16 @@ static int check_access_path_dual(
}
rule = find_rule(domain, walker_path.dentry);
- allowed_parent1 = unmask_layers(rule, access_masked_parent1,
- layer_masks_parent1);
- allowed_parent2 = unmask_layers(rule, access_masked_parent2,
- layer_masks_parent2);
+ allowed_parent1 = unmask_layers(
+ rule, access_masked_parent1, layer_masks_parent1,
+ ARRAY_SIZE(*layer_masks_parent1));
+ allowed_parent2 = unmask_layers(
+ rule, access_masked_parent2, layer_masks_parent2,
+ ARRAY_SIZE(*layer_masks_parent2));
/* Stops when a rule from each layer grants access. */
if (allowed_parent1 && allowed_parent2)
break;
-
jump_up:
if (walker_path.dentry == walker_path.mnt->mnt_root) {
if (follow_up(&walker_path)) {
@@ -564,7 +569,8 @@ static inline int check_access_path(const struct landlock_ruleset *const domain,
{
layer_mask_t layer_masks[LANDLOCK_NUM_ACCESS_FS] = {};
- access_request = init_layer_masks(domain, access_request, &layer_masks);
+ access_request = init_layer_masks(domain, access_request, &layer_masks,
+ LANDLOCK_KEY_INODE);
return check_access_path_dual(domain, path, access_request,
&layer_masks, NULL, 0, NULL, NULL);
}
@@ -648,7 +654,7 @@ static bool collect_domain_accesses(
return true;
access_dom = init_layer_masks(domain, LANDLOCK_MASK_ACCESS_FS,
- layer_masks_dom);
+ layer_masks_dom, LANDLOCK_KEY_INODE);
dget(dir);
while (true) {
@@ -656,7 +662,8 @@ static bool collect_domain_accesses(
/* Gets all layers allowing all domain accesses. */
if (unmask_layers(find_rule(domain, dir), access_dom,
- layer_masks_dom)) {
+ layer_masks_dom,
+ ARRAY_SIZE(*layer_masks_dom))) {
/*
* Stops when all handled accesses are allowed by at
* least one rule in each layer.
@@ -772,7 +779,7 @@ static int current_check_refer_path(struct dentry *const old_dentry,
*/
access_request_parent1 = init_layer_masks(
dom, access_request_parent1 | access_request_parent2,
- &layer_masks_parent1);
+ &layer_masks_parent1, LANDLOCK_KEY_INODE);
return check_access_path_dual(dom, new_dir,
access_request_parent1,
&layer_masks_parent1, NULL, 0,
diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c
index 671a95e2a345..84fcd8eb30d4 100644
--- a/security/landlock/ruleset.c
+++ b/security/landlock/ruleset.c
@@ -574,7 +574,8 @@ landlock_find_rule(const struct landlock_ruleset *const ruleset,
*/
You missed another hunk from my patch… Please do a diff with it.
bool unmask_layers(const struct landlock_rule *const rule,
const access_mask_t access_request,
- layer_mask_t (*const layer_masks)[LANDLOCK_NUM_ACCESS_FS])
+ layer_mask_t (*const layer_masks)[],
+ const size_t masks_array_size)
{
size_t layer_level;
@@ -606,8 +607,7 @@ bool unmask_layers(const struct landlock_rule *const rule,
* requested access.
*/
is_empty = true;
- for_each_set_bit(access_bit, &access_req,
- ARRAY_SIZE(*layer_masks)) {
+ for_each_set_bit(access_bit, &access_req, masks_array_size) {
if (layer->access & BIT_ULL(access_bit))
(*layer_masks)[access_bit] &= ~layer_bit;
is_empty = is_empty && !(*layer_masks)[access_bit];
@@ -618,15 +618,36 @@ bool unmask_layers(const struct landlock_rule *const rule,
return false;
}
-access_mask_t
-init_layer_masks(const struct landlock_ruleset *const domain,
- const access_mask_t access_request,
- layer_mask_t (*const layer_masks)[LANDLOCK_NUM_ACCESS_FS])
+typedef access_mask_t
+get_access_mask_t(const struct landlock_ruleset *const ruleset,
+ const u16 layer_level);
+
+/*
+ * @layer_masks must contain LANDLOCK_NUM_ACCESS_FS or LANDLOCK_NUM_ACCESS_NET
+ * elements according to @key_type.
+ */
+access_mask_t init_layer_masks(const struct landlock_ruleset *const domain,
+ const access_mask_t access_request,
+ layer_mask_t (*const layer_masks)[],
+ const enum landlock_key_type key_type)
{
access_mask_t handled_accesses = 0;
- size_t layer_level;
+ size_t layer_level, num_access;
+ get_access_mask_t *get_access_mask;
+
+ switch (key_type) {
+ case LANDLOCK_KEY_INODE:
+ get_access_mask = landlock_get_fs_access_mask;
+ num_access = LANDLOCK_NUM_ACCESS_FS;
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ return 0;
+ }
+
+ memset(layer_masks, 0,
+ array_size(sizeof((*layer_masks)[0]), num_access));
- memset(layer_masks, 0, sizeof(*layer_masks));
/* An empty access request can happen because of O_WRONLY | O_RDWR. */
if (!access_request)
return 0;
@@ -636,9 +657,8 @@ init_layer_masks(const struct landlock_ruleset *const domain,
const unsigned long access_req = access_request;
unsigned long access_bit;
- for_each_set_bit(access_bit, &access_req,
- ARRAY_SIZE(*layer_masks)) {
- if (landlock_get_fs_access_mask(domain, layer_level) &
+ for_each_set_bit(access_bit, &access_req, num_access) {
+ if (get_access_mask(domain, layer_level) &
BIT_ULL(access_bit)) {
(*layer_masks)[access_bit] |=
BIT_ULL(layer_level);
diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h
index d7d9b987829c..2083855bf42d 100644
--- a/security/landlock/ruleset.h
+++ b/security/landlock/ruleset.h
@@ -238,11 +238,12 @@ landlock_get_fs_access_mask(const struct landlock_ruleset *const ruleset,
bool unmask_layers(const struct landlock_rule *const rule,
const access_mask_t access_request,
- layer_mask_t (*const layer_masks)[LANDLOCK_NUM_ACCESS_FS]);
+ layer_mask_t (*const layer_masks)[],
+ const size_t masks_array_size);
-access_mask_t
-init_layer_masks(const struct landlock_ruleset *const domain,
- const access_mask_t access_request,
- layer_mask_t (*const layer_masks)[LANDLOCK_NUM_ACCESS_FS]);
+access_mask_t init_layer_masks(const struct landlock_ruleset *const domain,
+ const access_mask_t access_request,
+ layer_mask_t (*const layer_masks)[],
+ const enum landlock_key_type key_type);
#endif /* _SECURITY_LANDLOCK_RULESET_H */
--
2.25.1
