On 7/19/2024 10:08 AM, Paul Moore wrote:
On Jul 11, 2024 Xu Kuohai <xukuo...@huaweicloud.com> wrote:

To be consistent with most LSM hooks, convert the return value of
hook inode_copy_up_xattr to 0 or a negative error code.

Before:
- Hook inode_copy_up_xattr returns 0 when accepting xattr, 1 when
   discarding xattr, -EOPNOTSUPP if it does not know xattr, or any
   other negative error code otherwise.

After:
- Hook inode_copy_up_xattr returns 0 when accepting xattr, *-ECANCELED*
   when discarding xattr, -EOPNOTSUPP if it does not know xattr, or
   any other negative error code otherwise.

Signed-off-by: Xu Kuohai <xukuo...@huawei.com>
---
  fs/overlayfs/copy_up.c            |  6 +++---
  security/integrity/evm/evm_main.c |  2 +-
  security/security.c               | 12 ++++++------
  security/selinux/hooks.c          |  4 ++--
  security/smack/smack_lsm.c        |  6 +++---
  5 files changed, 15 insertions(+), 15 deletions(-)

...

diff --git a/security/security.c b/security/security.c
index 26eea8f4cd74..12215ca286af 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2675,18 +2675,18 @@ EXPORT_SYMBOL(security_inode_copy_up);
   * lower layer to the union/overlay layer.   The caller is responsible for
   * reading and writing the xattrs, this hook is merely a filter.
   *
- * Return: Returns 0 to accept the xattr, 1 to discard the xattr, -EOPNOTSUPP
- *         if the security module does not know about attribute, or a negative
- *         error code to abort the copy up.
+ * Return: Returns 0 to accept the xattr, -ECANCELED to discard the xattr,
+ *         -EOPNOTSUPP if the security module does not know about attribute,
+ *         or a negative error code to abort the copy up.
   */
  int security_inode_copy_up_xattr(struct dentry *src, const char *name)
  {
        int rc;
/*
-        * The implementation can return 0 (accept the xattr), 1 (discard the
-        * xattr), -EOPNOTSUPP if it does not know anything about the xattr or
-        * any other error code in case of an error.
+        * The implementation can return 0 (accept the xattr), -ECANCELED
+        * (discard the xattr), -EOPNOTSUPP if it does not know anything
+        *  about the xattr or any other error code in case of an error.
         */

Updating the comment here is good, but considering that we also discuss
the return value in the function header comment, I think it might be
better to just remove this comment entirely and leave the function header
comment as the single source.  Duplicated comments/docs tend to fall out
of sync and create confusion.


OK, will do

        rc = call_int_hook(inode_copy_up_xattr, src, name);
        if (rc != LSM_RET_DEFAULT(inode_copy_up_xattr))


--
paul-moore.com



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