10/18/2023 7:34 PM, Mickaël Salaün пишет:
On Mon, Oct 16, 2023 at 09:50:25AM +0800, Konstantin Meskhidze wrote:
Change the landlock_add_rule() syscall to support new rule types
in future Landlock versions. Add the add_rule_path_beneath() helper
to support current filesystem rules.
Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230920092641.832134-8-konstantin.meskhidze@xxxxxxxxxx
Signed-off-by: Mickaël Salaün <mic@xxxxxxxxxxx>
---
Changes since v12:
* None.
Changes since v11:
* None.
Changes since v10:
* None.
Changes since v9:
* Minor fixes:
- deletes unnecessary curly braces.
- deletes unnecessary empty line.
Changes since v8:
* Refactors commit message.
* Minor fixes.
Changes since v7:
* None
Changes since v6:
* None
Changes since v5:
* Refactors syscall landlock_add_rule() and add_rule_path_beneath() helper
to make argument check ordering consistent and get rid of partial revertings
in following patches.
* Rolls back refactoring base_test.c seltest.
* Formats code with clang-format-14.
Changes since v4:
* Refactors add_rule_path_beneath() and landlock_add_rule() functions
to optimize code usage.
* Refactors base_test.c seltest: adds LANDLOCK_RULE_PATH_BENEATH
rule type in landlock_add_rule() call.
Changes since v3:
* Split commit.
* Refactors landlock_add_rule syscall.
---
security/landlock/syscalls.c | 92 +++++++++++++++++++-----------------
1 file changed, 48 insertions(+), 44 deletions(-)
diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c
index d35cd5d304db..8a54e87dbb17 100644
--- a/security/landlock/syscalls.c
+++ b/security/landlock/syscalls.c
@@ -274,6 +274,47 @@ static int get_path_from_fd(const s32 fd, struct path *const path)
return err;
}
+static int add_rule_path_beneath(struct landlock_ruleset *const ruleset,
+ const void __user *const rule_attr)
+{
+ struct landlock_path_beneath_attr path_beneath_attr;
+ struct path path;
+ int res, err;
+ access_mask_t mask;
+
+ /* Copies raw user space buffer, only one type for now. */
+ res = copy_from_user(&path_beneath_attr, rule_attr,
+ sizeof(path_beneath_attr));
+ if (res)
+ return -EFAULT;
+
+ /*
+ * Informs about useless rule: empty allowed_access (i.e. deny rules)
+ * are ignored in path walks.
+ */
+ if (!path_beneath_attr.allowed_access)
+ return -ENOMSG;
+
+ /*
+ * Checks that allowed_access matches the @ruleset constraints
+ * (ruleset->access_masks[0] is automatically upgraded to 64-bits).
+ */
You now can replace this comment block with that:
+ /* Checks that allowed_access matches the @ruleset constraints. */
Done.
+ mask = landlock_get_raw_fs_access_mask(ruleset, 0);
+ if ((path_beneath_attr.allowed_access | mask) != mask)
+ return -EINVAL;
+
+ /* Gets and checks the new rule. */
+ err = get_path_from_fd(path_beneath_attr.parent_fd, &path);
+ if (err)
+ return err;
+
+ /* Imports the new rule. */
+ err = landlock_append_fs_rule(ruleset, &path,
+ path_beneath_attr.allowed_access);
+ path_put(&path);
+ return err;
+}
.
