Re: [PATCH v3] kernel: Conditionally support non-root users, groups and capabilities

From: Iulia Manda
Date: Wed Feb 11 2015 - 10:09:37 EST


On 10 February 2015 at 02:33, Paul E. McKenney
<paulmck@xxxxxxxxxxxxxxxxxx> wrote:
> On Mon, Feb 09, 2015 at 03:42:08PM -0800, josh@xxxxxxxxxxxxxxxx wrote:
>> On Sun, Feb 08, 2015 at 10:05:25AM +0100, Geert Uytterhoeven wrote:
>> > Thanks for the update!
>> >
>> > Acked-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
>>

See below. :)

>> Thanks, Geert!
>>
>> On Sun, Feb 08, 2015 at 08:02:17PM -0800, Paul E. McKenney wrote:
>> > I presume that v4 will have your Signed-off-by. ;-)
>> >
>> > Testing on my rcutorture setup uncovered an additional required dependency,
>> > please see patch at the end of this email. With that fix, either separately
>> > or merged into your patch:
>> >
>> > Tested-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
>> >
>> > One question below about moving the definition of capable(). Either way:
>>
>> Answer below.
>
> And that answer makes sense to me! Might be worth a mention in the
> commit log (my apologies if it was mentioned and I missed it).
>
>> > Reviewed-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
>>
>> Thanks, Paul!
>>
>> Based on this feedback, as well as the feedback from others on prior
>> versions that has since been addressed, once there's a v4 with the
>> changes suggested by Paul (and the signoff and acks/reviews added), I'm
>> going to let this patch start cooking in linux-next (after the currently
>> active merge window closes, of course). That'll help shake out any
>> other potential missing dependencies or merge issues, and leave plenty
>> of time for people to discuss it further before the subsequent merge
>> window.
>

Thank you for the feedback and review!

> Makes sense to me! (/me suddenly remembers to take his post-merge-window
> commits out of -next...)
>
> Thanx, Paul
>
>> > > --- a/kernel/capability.c
>> > > +++ b/kernel/capability.c
>> > > @@ -35,6 +35,7 @@ static int __init file_caps_disable(char *str)
>> > > }
>> > > __setup("no_file_caps", file_caps_disable);
>> > >
>> > > +#ifdef CONFIG_MULTIUSER
>> > > /*
>> > > * More recent versions of libcap are available from:
>> > > *
>> > > @@ -386,6 +387,24 @@ bool ns_capable(struct user_namespace *ns, int cap)
>> > > }
>> > > EXPORT_SYMBOL(ns_capable);
>> > >
>> > > +
>> > > +/**
>> > > + * capable - Determine if the current task has a superior capability in effect
>> > > + * @cap: The capability to be tested for
>> > > + *
>> > > + * Return true if the current task has the given superior capability currently
>> > > + * available for use, false if not.
>> > > + *
>> > > + * This sets PF_SUPERPRIV on the task if the capability is available on the
>> > > + * assumption that it's about to be used.
>> > > + */
>> > > +bool capable(int cap)
>> > > +{
>> > > + return ns_capable(&init_user_ns, cap);
>> > > +}
>> > > +EXPORT_SYMBOL(capable);
>> > > +#endif /* CONFIG_MULTIUSER */
>> > > +
>> > > /**
>> > > * file_ns_capable - Determine if the file's opener had a capability in effect
>> > > * @file: The file we want to check
>> > > @@ -412,22 +431,6 @@ bool file_ns_capable(const struct file *file, struct user_namespace *ns,
>> > > EXPORT_SYMBOL(file_ns_capable);
>> > >
>> > > /**
>> > > - * capable - Determine if the current task has a superior capability in effect
>> > > - * @cap: The capability to be tested for
>> > > - *
>> > > - * Return true if the current task has the given superior capability currently
>> > > - * available for use, false if not.
>> > > - *
>> > > - * This sets PF_SUPERPRIV on the task if the capability is available on the
>> > > - * assumption that it's about to be used.
>> > > - */
>> > > -bool capable(int cap)
>> > > -{
>> > > - return ns_capable(&init_user_ns, cap);
>> > > -}
>> > > -EXPORT_SYMBOL(capable);
>> > > -
>> > > -/**
>> >
>> > OK, I'll bite... Why are we moving capable()?
>>
>> Consolidating from two ifdef blocks to one, based on feedback on the
>> initial version suggesting simplification of the ifdeffery.
>>
>> - Josh Triplett
>>
>
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