linux-kernel - Re: overlayfs vs. fscrypt

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Message-ID: <CAJfpegvrG4LfnuC62JNtdXpCf4vb+aEiDre5YCxe7xUSQP8yjw@mail.gmail.com>
Date:   Wed, 13 Mar 2019 13:58:11 +0100
From:   Miklos Szeredi <miklos@...redi.hu>
To:     Richard Weinberger <richard@....at>
Cc:     linux-fsdevel@...r.kernel.org, linux-fscrypt@...r.kernel.org,
        overlayfs <linux-unionfs@...r.kernel.org>,
        linux-kernel@...r.kernel.org
Subject: Re: overlayfs vs. fscrypt

On Wed, Mar 13, 2019 at 1:47 PM Richard Weinberger <richard@....at> 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?

Thanks,
Miklos