On Fri, 2016-07-01 at 14:56 +0200, Miklos Szeredi wrote:
> (Another one for the f_path debacle.)
>
> ltp fcntl33 testcase caused an Oops in selinux_file_send_sigiotask.
>
> The reason is that generic_add_lease() used filp->f_path.dentry->inode
> while all the others use file_inode(). This makes a difference for files
> opened on overlayfs since the former will point to the overlay inode the
> latter to the underlying inode.
>
> So generic_add_lease() added the lease to the overlay inode and
> generic_delete_lease() removed it from the underlying inode. When the file
> was released the lease remained on the overlay inode's lock list, resulting
> in use after free.
>
> Reported-by: Eryu Guan <eguan@xxxxxxxxxx>
> Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
> Fixes: 4bacc9c9234c ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay")
> Cc: <stable@xxxxxxxxxxxxxxx>
> Cc: Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
> Cc: "J. Bruce Fields" <bfields@xxxxxxxxxxxx>
> ---
> fs/locks.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/locks.c b/fs/locks.c
> index 7c5f91be9b65..ee1b15f6fc13 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -1628,7 +1628,7 @@ generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **pr
> {
> struct file_lock *fl, *my_fl = NULL, *lease;
> struct dentry *dentry = filp->f_path.dentry;
> - struct inode *inode = dentry->d_inode;
> + struct inode *inode = file_inode(filp);
> struct file_lock_context *ctx;
> bool is_deleg = (*flp)->fl_flags & FL_DELEG;
> int error;
Looks good. Al or Bruce, if either of you have remaining patches this
cycle then could one of you take this one? Otherwise, I can queue up a
branch with it.
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
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