Re: [PATCH] Revert "ext4 crypto: fix to check feature status before get policy"

From: Guenter Roeck
Date: Sat Nov 02 2019 - 18:10:32 EST


On Fri, Nov 1, 2019 at 11:17 AM Guenter Roeck <groeck@xxxxxxxxxx> wrote:
[ ... ]
> > Ah, I think I found it:
> >
> > https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/2cbdedd5eca0a57d9596671a99da5fab8e60722b/sys-apps/upstart/files/upstart-1.2-dircrypto.patch
> >
> > The init process does EXT4_IOC_GET_ENCRYPTION_POLICY on /, and if the error is
> > EOPNOTSUPP, it skips creating the "dircrypto" keyring. So then cryptohome can't
> > add keys later. (Note the error message you got, "Error adding dircrypto key".)
> >
> > So it looks like the kernel patch broke both that and
> > ext4_dir_encryption_supported().
> >
>
> ext4_dir_encryption_supported() was already changed to use the sysfs
> file, and changing the upstart code to check the sysfs file does
> indeed fix the problem for good. I'll do some more tests and push the
> necessary changes into our code base if I don't hit some other issue.
>

This change is now in our code base:

https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/5c5b06fded399013b9cce3d504c3d968ee84ab8b

If the revert has not made it upstream, I would suggest to hold it off
for the time being. I'll do more testing next week, but as it looks
like it may no longer be needed, at least not from a Chrome OS
perspective.

Guenter