From: Theodore Ts'o Subject: [PATCH 4/5] ext4: use file_dentry() Date: Sat, 26 Mar 2016 17:09:59 -0400 Message-ID: <1459026600-9232-5-git-send-email-tytso@mit.edu> References: <1459026600-9232-1-git-send-email-tytso@mit.edu> Cc: dhowells@redhat.com, viro@ZenIV.linux.org.uk, Linux Filesystem Development List , jaegeuk@kernel.org, Miklos Szeredi , Theodore Ts'o , Al Viro , To: Ext4 Developers List Return-path: In-Reply-To: <1459026600-9232-1-git-send-email-tytso@mit.edu> Sender: stable-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org From: Miklos Szeredi 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 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 Signed-off-by: Theodore Ts'o Cc: David Howells Cc: Al Viro Cc: # v4.5 --- fs/ext4/file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/ext4/file.c b/fs/ext4/file.c index 257118d..edba9fb 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -374,7 +374,7 @@ 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, -- 2.5.0