The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 5e1275808630ea3b2c97c776f40e475017535f72 Mon Sep 17 00:00:00 2001
From: Miklos Szeredi mszeredi@redhat.com Date: Wed, 31 Oct 2018 12:15:23 +0100 Subject: [PATCH] ovl: check whiteout in ovl_create_over_whiteout()
Kaixuxia repors that it's possible to crash overlayfs by removing the whiteout on the upper layer before creating a directory over it. This is a reproducer:
mkdir lower upper work merge touch lower/file mount -t overlay overlay -olowerdir=lower,upperdir=upper,workdir=work merge rm merge/file ls -al merge/file rm upper/file ls -al merge/ mkdir merge/file
Before commencing with a vfs_rename(..., RENAME_EXCHANGE) verify that the lookup of "upper" is positive and is a whiteout, and return ESTALE otherwise.
Reported by: kaixuxia xiakaixu1987@gmail.com Signed-off-by: Miklos Szeredi mszeredi@redhat.com Fixes: e9be9d5e76e3 ("overlay filesystem") Cc: stable@vger.kernel.org # v3.18
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c index ce1857fb5434..c6289147c787 100644 --- a/fs/overlayfs/dir.c +++ b/fs/overlayfs/dir.c @@ -462,6 +462,10 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, if (IS_ERR(upper)) goto out_unlock;
+ err = -ESTALE; + if (d_is_negative(upper) || !IS_WHITEOUT(d_inode(upper))) + goto out_dput; + newdentry = ovl_create_temp(workdir, cattr); err = PTR_ERR(newdentry); if (IS_ERR(newdentry))
On Thu, Nov 15, 2018 at 1:08 AM gregkh@linuxfoundation.org wrote:
The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
Attaching backport. Should also apply cleanly to v3.18..v4.9
Thanks, Miklos
On Thu, Nov 15, 2018 at 10:42:20AM +0100, Miklos Szeredi wrote:
On Thu, Nov 15, 2018 at 1:08 AM gregkh@linuxfoundation.org wrote:
The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
Attaching backport. Should also apply cleanly to v3.18..v4.9
This doesn't apply at all, are you sure you generated it properly? Can you try it again?
thanks,
greg k-h
On Mon, Nov 19, 2018 at 4:08 PM Greg Kroah-Hartman gregkh@linuxfoundation.org wrote:
On Thu, Nov 15, 2018 at 10:42:20AM +0100, Miklos Szeredi wrote:
On Thu, Nov 15, 2018 at 1:08 AM gregkh@linuxfoundation.org wrote:
The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
Attaching backport. Should also apply cleanly to v3.18..v4.9
This doesn't apply at all, are you sure you generated it properly? Can you try it again?
Okay. I only looked at the base kernel, not the stable one, so probably there's some conflict in the stable patches themselves.
Thanks, Miklos
linux-stable-mirror@lists.linaro.org