Re: overlayfs vs. fscrypt

[Richard Weinberger]

Am Mittwoch, 13. März 2019, 13:58:11 CET schrieb Miklos Szeredi:
> On Wed, Mar 13, 2019 at 1:47 PM Richard Weinberger <richard@xxxxxx> wrote:
> >
> > Am Mittwoch, 13. März 2019, 13:36:02 CET schrieb Miklos Szeredi:
> > > I don't get it.  Does fscrypt try to check permissions via
> > > ->d_revalidate?  Why is it not doing that via ->permission()?
> >
> > Please let me explain. Suppose we have a fscrypto directory /mnt and
> > I *don't* have the key.
> >
> > When reading the directory contents of /mnt will return an encrypted filename.
> > e.g.
> > # ls /mnt
> > +mcQ46ne5Y8U6JMV9Wdq2C
> 
> Why does showing the encrypted contents make any sense?  It could just
> return -EPERM on all operations?

The use case is that you can delete these files if the DAC/MAC permissions allow it.
Just like on NTFS. If a user encrypts files, the admin cannot read them but can
remove them if the user is gone or loses the key.

Thanks,
//richard