Re: [PATCH] Smack: Restore the smackfsdef mount option

From: David Howells
Date: Tue May 28 2019 - 14:57:56 EST


Casey Schaufler <casey@xxxxxxxxxxxxxxxx> wrote:

> > Casey Schaufler <casey@xxxxxxxxxxxxxxxx> wrote:
> >
> >>> Also, should all of these be prefixed with "smack"? So:
> >>>
> >>> fsparam_string("smackfsdef", Opt_fsdefault),
> >>> fsparam_string("smackfsfloor", Opt_fsfloor),
> >>> fsparam_string("smackfshat", Opt_fshat),
> >> No. smack_fs_parameters takes care of that.
> > It does? *Blink*.
>
> Well, something does. I can't say that I 100% understand all
> of how the new mount code handles the mount options. Y'all made
> sweeping changes, and the code works the way it used to except
> for the awkward change from smackfsdef to smackfsdefault. It
> took no small amount of head scratching and experimentation to
> convince myself that the fix I proposed was correct.

Ah... I suspect the issue is that smack_sb_eat_lsm_opts() strips the prefix
for an unconverted filesystem, but smack_fs_context_parse_param() doesn't
(which it shouldn't).

Can you try grabbing my mount-api-viro branch from:

https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git

and testing setting smack options on a tmpfs filesystem?

You might need to try modifying samples/vfs/test-fsmount.c to make it mount a
trmpfs filesystem through the new mount UAPI.

David