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

From: Casey Schaufler
Date: Tue May 28 2019 - 16:28:14 EST


On 5/28/2019 12:57 PM, Casey Schaufler wrote:
> On 5/28/2019 11:54 AM, David Howells wrote:
>> 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?
> My fedora system won't boot because smackfsdef isn't recognized. :(
> I will put in my fix and retry.

No joy there, either. Now it accepts smackfsdef, but doesn't
recognize smackfsroot. I don't have this problem with vanilla
5.1.

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