[RFC PATCH v6 5/9] vfs: lookup_open(): move audit_inode_child() and i_op->create check to before try_break_deleg()

[Jori Koolstra]

Calling audit_inode_child() and the i_op->create check in lookup_open()
take place after the try_break_deleg() call. This does not match the
order when doing a regular file create via mknod(2). There the call
order is:

	filename_mknodat()
	vfs_create()
	may_create_dentry()
	audit_inode_child(dir, child, AUDIT_TYPE_CHILD_CREATE)
	i_op->create check
	try_break_deleg()

In particular, audit_inode_child() is called regardless of whether
try_break_deleg() fails.

Move move audit_inode_child() and the i_op->create check to before
try_break_deleg() in lookup_open().

Signed-off-by: Jori Koolstra <jkoolstra@xxxxxxxxx>
---
 fs/namei.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 16dcf537db87..293592a4d011 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4526,17 +4526,18 @@ static struct dentry *lookup_open(struct nameidata *nd, struct file *file,
 
 	/* Negative dentry, just create the file */
 	if (!dentry->d_inode && (open_flag & O_CREAT)) {
-		/* but break the directory lease first! */
-		error = try_break_deleg(dir_inode, delegated_inode);
-		if (error)
-			goto out_dput;
-
 		audit_inode_child(dir_inode, dentry, AUDIT_TYPE_CHILD_CREATE);
+
 		if (!dir_inode->i_op->create) {
 			error = -EACCES;
 			goto out_dput;
 		}
 
+		/* but break the directory lease first! */
+		error = try_break_deleg(dir_inode, delegated_inode);
+		if (error)
+			goto out_dput;
+
 		error = dir_inode->i_op->create(idmap, dir_inode, dentry,
 						mode, open_flag & O_EXCL);
 		if (error)
-- 
2.54.0