diff mbox

[4/4] ext4: use file_dentry()

Message ID 1458205323-25685-4-git-send-email-miklos@szeredi.hu (mailing list archive)
State New, archived
Headers show

Commit Message

Miklos Szeredi March 17, 2016, 9:02 a.m. UTC 
From: Miklos Szeredi <mszeredi@redhat.com>

EXT4 may be used as lower layer of overlayfs and accessing f_path.dentry
can lead to a crash.

Fix by replacing direct access of file->f_path.dentry with the
file_dentry() accessor, which will always return a native object.

Reported-by: Daniel Axtens <dja@axtens.net>
Fixes: 4bacc9c9234c ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay")
Fixes: ff978b09f973 ("ext4 crypto: move context consistency check to ext4_file_open()")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org> # v4.5
---
 fs/ext4/file.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox

Patch

diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index feb9ffc6f20d..38847f38b34a 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -380,7 +380,7 @@  static int ext4_file_open(struct inode * inode, struct file * filp)
 			return -ENOKEY;
 	}
 
-	dir = dget_parent(filp->f_path.dentry);
+	dir = dget_parent(file_dentry(filp));
 	if (ext4_encrypted_inode(d_inode(dir)) &&
 	    !ext4_is_child_context_consistent_with_parent(d_inode(dir), inode)) {
 		ext4_warning(inode->i_sb,