On 21/06/2022 10:22, Konstantin Meskhidze wrote:
To support network type rules,
this modification extends and renames
ruleset's access masks.
This patch adds filesystem helper functions
to set and get filesystem mask. Also the
modification adds a helper structure
landlock_access_mask to support managing
multiple access mask.
Please use a text-width of 72 columns for all commit messages. You can
also split them into paragraphs.
Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@xxxxxxxxxx>
---
Changes since v5:
* Changes access_mask_t to u32.
* Formats code with clang-format-14.
Changes since v4:
* Deletes struct landlock_access_mask.
Changes since v3:
* Splits commit.
* Adds get_mask, set_mask helpers for filesystem.
* Adds new struct landlock_access_mask.
---
security/landlock/fs.c | 7 ++++---
security/landlock/ruleset.c | 18 +++++++++---------
security/landlock/ruleset.h | 25 ++++++++++++++++++++-----
security/landlock/syscalls.c | 7 ++++---
4 files changed, 37 insertions(+), 20 deletions(-)
diff --git a/security/landlock/fs.c b/security/landlock/fs.c
index ec5a6247cd3e..e6da08ed99d1 100644
--- a/security/landlock/fs.c
+++ b/security/landlock/fs.c
@@ -167,7 +167,8 @@ int landlock_append_fs_rule(struct landlock_ruleset *const ruleset,
return -EINVAL;
/* Transforms relative access rights to absolute ones. */
- access_rights |= LANDLOCK_MASK_ACCESS_FS & ~ruleset->fs_access_masks[0];
+ access_rights |= LANDLOCK_MASK_ACCESS_FS &
+ ~landlock_get_fs_access_mask(ruleset, 0);
object = get_inode_object(d_backing_inode(path->dentry));
if (IS_ERR(object))
return PTR_ERR(object);
@@ -286,7 +287,7 @@ get_handled_accesses(const struct landlock_ruleset *const domain)
for (layer_level = 0; layer_level < domain->num_layers;
layer_level++) {
- if (domain->fs_access_masks[layer_level] &
+ if (landlock_get_fs_access_mask(domain, layer_level) &
BIT_ULL(access_bit)) {
access_dom |= BIT_ULL(access_bit);
break;
@@ -316,7 +317,7 @@ init_layer_masks(const struct landlock_ruleset *const domain,
for_each_set_bit(access_bit, &access_req,
ARRAY_SIZE(*layer_masks)) {
- if (domain->fs_access_masks[layer_level] &
+ if (landlock_get_fs_access_mask(domain, layer_level) &
BIT_ULL(access_bit)) {
(*layer_masks)[access_bit] |=
BIT_ULL(layer_level);
diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c
index 996484f98bfd..a3fd58d01f09 100644
--- a/security/landlock/ruleset.c
+++ b/security/landlock/ruleset.c
@@ -29,7 +29,7 @@ static struct landlock_ruleset *create_ruleset(const u32 num_layers)
struct landlock_ruleset *new_ruleset;
new_ruleset =
- kzalloc(struct_size(new_ruleset, fs_access_masks, num_layers),
+ kzalloc(struct_size(new_ruleset, access_masks, num_layers),
GFP_KERNEL_ACCOUNT);
if (!new_ruleset)
return ERR_PTR(-ENOMEM);
@@ -40,22 +40,22 @@ static struct landlock_ruleset *create_ruleset(const u32 num_layers)
/*
* hierarchy = NULL
* num_rules = 0
- * fs_access_masks[] = 0
+ * access_masks[] = 0
*/
return new_ruleset;
}
struct landlock_ruleset *
-landlock_create_ruleset(const access_mask_t fs_access_mask)
+landlock_create_ruleset(const access_mask_t access_mask)
{
struct landlock_ruleset *new_ruleset;
/* Informs about useless ruleset. */
- if (!fs_access_mask)
+ if (!access_mask)
return ERR_PTR(-ENOMSG);
new_ruleset = create_ruleset(1);
if (!IS_ERR(new_ruleset))
- new_ruleset->fs_access_masks[0] = fs_access_mask;
+ landlock_set_fs_access_mask(new_ruleset, access_mask, 0);
return new_ruleset;
}
@@ -117,7 +117,7 @@ static void build_check_ruleset(void)
.num_rules = ~0,
.num_layers = ~0,
};
- typeof(ruleset.fs_access_masks[0]) fs_access_mask = ~0;
+ typeof(ruleset.access_masks[0]) fs_access_mask = ~0;
BUILD_BUG_ON(ruleset.num_rules < LANDLOCK_MAX_NUM_RULES);
BUILD_BUG_ON(ruleset.num_layers < LANDLOCK_MAX_NUM_LAYERS);
@@ -281,7 +281,7 @@ static int merge_ruleset(struct landlock_ruleset *const dst,
err = -EINVAL;
goto out_unlock;
}
- dst->fs_access_masks[dst->num_layers - 1] = src->fs_access_masks[0];
+ dst->access_masks[dst->num_layers - 1] = src->access_masks[0];
/* Merges the @src tree. */
rbtree_postorder_for_each_entry_safe(walker_rule, next_rule, &src->root,
@@ -340,8 +340,8 @@ static int inherit_ruleset(struct landlock_ruleset *const parent,
goto out_unlock;
}
/* Copies the parent layer stack and leaves a space for the new layer. */
- memcpy(child->fs_access_masks, parent->fs_access_masks,
- flex_array_size(parent, fs_access_masks, parent->num_layers));
+ memcpy(child->access_masks, parent->access_masks,
+ flex_array_size(parent, access_masks, parent->num_layers));
if (WARN_ON_ONCE(!parent->hierarchy)) {
err = -EINVAL;
diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h
index d43231b783e4..bd7ab39859bf 100644
--- a/security/landlock/ruleset.h
+++ b/security/landlock/ruleset.h
@@ -19,7 +19,7 @@
#include "limits.h"
#include "object.h"
-typedef u16 access_mask_t;
+typedef u32 access_mask_t;
/* Makes sure all filesystem access rights can be stored. */
static_assert(BITS_PER_TYPE(access_mask_t) >= LANDLOCK_NUM_ACCESS_FS);
/* Makes sure for_each_set_bit() and for_each_clear_bit() calls are OK. */
@@ -110,7 +110,7 @@ struct landlock_ruleset {
* section. This is only used by
* landlock_put_ruleset_deferred() when @usage reaches zero.
* The fields @lock, @usage, @num_rules, @num_layers and
- * @fs_access_masks are then unused.
+ * @access_masks are then unused.
*/
struct work_struct work_free;
struct {
@@ -137,7 +137,7 @@ struct landlock_ruleset {
*/
u32 num_layers;
/**
- * @fs_access_masks: Contains the subset of filesystem
+ * @access_masks: Contains the subset of filesystem
* actions that are restricted by a ruleset. A domain
* saves all layers of merged rulesets in a stack
* (FAM), starting from the first layer to the last
@@ -148,13 +148,13 @@ struct landlock_ruleset {
* layers are set once and never changed for the
* lifetime of the ruleset.
*/
- access_mask_t fs_access_masks[];
+ access_mask_t access_masks[];
};
};
};
struct landlock_ruleset *
-landlock_create_ruleset(const access_mask_t fs_access_mask);
+landlock_create_ruleset(const access_mask_t access_mask);
void landlock_put_ruleset(struct landlock_ruleset *const ruleset);
void landlock_put_ruleset_deferred(struct landlock_ruleset *const ruleset);
@@ -177,4 +177,19 @@ static inline void landlock_get_ruleset(struct landlock_ruleset *const ruleset)
refcount_inc(&ruleset->usage);
}
+/* A helper function to set a filesystem mask. */
+static inline void
+landlock_set_fs_access_mask(struct landlock_ruleset *ruleset,
+ const access_mask_t access_maskset, u16 mask_level)
+{
+ ruleset->access_masks[mask_level] = access_maskset;
+}
+
+/* A helper function to get a filesystem mask. */
+static inline u32
You need to use access_mask_t everywhere, including here.
+landlock_get_fs_access_mask(const struct landlock_ruleset *ruleset,
+ u16 mask_level)
+{
+ return ruleset->access_masks[mask_level];
+}
#endif /* _SECURITY_LANDLOCK_RULESET_H */
diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c
index 735a0865ea11..5836736ce9d7 100644
--- a/security/landlock/syscalls.c
+++ b/security/landlock/syscalls.c
@@ -346,10 +346,11 @@ SYSCALL_DEFINE4(landlock_add_rule, const int, ruleset_fd,
}
/*
* Checks that allowed_access matches the @ruleset constraints
- * (ruleset->fs_access_masks[0] is automatically upgraded to 64-bits).
+ * (ruleset->access_masks[0] is automatically upgraded to 64-bits).
*/
- if ((path_beneath_attr.allowed_access | ruleset->fs_access_masks[0]) !=
- ruleset->fs_access_masks[0]) {
+ if ((path_beneath_attr.allowed_access |
+ landlock_get_fs_access_mask(ruleset, 0)) !=
+ landlock_get_fs_access_mask(ruleset, 0)) {
err = -EINVAL;
goto out_put_ruleset;
}
--
2.25.1
