Re: [RFC PATCH v3 07/18] fscrypt: add FS_IOC_ADD_ENCRYPTION_KEY ioctl

[Richard Weinberger <richard@nod.at>]

Ericm

Am Dienstag, 19. März 2019, 00:08:31 CET schrieb Eric Biggers:
> I tried using sb->s_bdi->name, but it's still "ubifs" for all UBIFS filesystems.

hmpf.
 
> Perhaps there's a way you can make ->s_id for UBIFS unique?  There are already
> existing places that log ->s_id, so perhaps you should do it anyway regardless
> of this patchset?

Yes, let me implement that.
ubifs does:
super_setup_bdi_name(sb, "ubifs_%d_%d", c->vi.ubi_num, c->vi.vol_id);

So, I try to set ->s_id also to ubifs_%d_%d.

> > > 
> > > > Note that the keyring name isn't particularly important, since the ioctls will
> > > > work regardless.  But we might as well choose something logical, since the
> > > > keyring name will still show up in /proc/keys.
> > > 
> > > I'm not done with reviewing your patches, but will it be possible to use keyctl?
> > > For the a unique name is helpful. :)
> > > 
> > 
> > Not for adding keys, removing keys, or getting a key's status -- those are what
> > the ioctls are for.
> > 
> > See e.g. the discussion in patch 7 ("fscrypt: add FS_IOC_ADD_ENCRYPTION_KEY
> > ioctl") for why the keyrings syscalls are a poor fit for fscrypt.
> > 
> 
> Anyway, perhaps I should reconsider whether fscrypt should even use the keyrings
> subsystem at all, even just "internally", as its quirks still leak out a bit.
> I'd prefer a nice clean API without any quirks like having to name the keyrings
> and assign SELinux labels to the keys just to make the keyrings subsystem happy.

IMHO the keys subsytem is a good fit. For example for stuff like this one:
https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1945778.html

We use UBIFS on many embedded systems with crypto hardware.

Thanks,
//richard