2/10/2023 8:38 PM, Mickaël Salaün пишет:

On 16/01/2023 09:58, Konstantin Meskhidze wrote:

quoted

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 <redacted>
---

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 | 94 +++++++++++++++++++-----------------
  1 file changed, 50 insertions(+), 44 deletions(-)

diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c
index d35cd5d304db..73c80cd2cdbe 100644
--- a/security/landlock/syscalls.c
+++ b/security/landlock/syscalls.c

@@ -274,6 +274,49 @@ 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;
+	}

Please follows the ./scripts/checkpatch.pl conventions (i.e. no curly
braces). You should add an empty line after this return though.

  Ok. I will fix it.

quoted

+	/*
+	 * Checks that allowed_access matches the @ruleset constraints
+	 * (ruleset->access_masks[0] is automatically upgraded to 64-bits).
+	 */
+	mask = landlock_get_raw_fs_access_mask(ruleset, 0);
+	if ((path_beneath_attr.allowed_access | mask) != mask) {
+		return -EINVAL;
+	}

Same here.

   Got it.

quoted

+
+	/* 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);
+

No need for this empty line.

   Ok. Thanks for noticing.

quoted

+	return err;
+}
+

.