Re: [PATCH v3 0/4] Introduce security_create_user_ns()

[Frederick Lawler]

On 7/22/22 7:20 AM, Paul Moore wrote:
> On July 22, 2022 2:12:03 AM Martin KaFai Lau <kafai@xxxxxx> wrote:
>
> > On Thu, Jul 21, 2022 at 12:28:04PM -0500, Frederick Lawler wrote:
> > > While creating a LSM BPF MAC policy to block user namespace creation, we
> > > used the LSM cred_prepare hook because that is the closest hook to prevent
> > > a call to create_user_ns().
> > >
> > > The calls look something like this:
> > >
> > > cred = prepare_creds()
> > > security_prepare_creds()
> > > call_int_hook(cred_prepare, ...
> > > if (cred)
> > > create_user_ns(cred)
> > >
> > > We noticed that error codes were not propagated from this hook and
> > > introduced a patch [1] to propagate those errors.
> > >
> > > The discussion notes that security_prepare_creds()
> > > is not appropriate for MAC policies, and instead the hook is
> > > meant for LSM authors to prepare credentials for mutation. [2]
> > >
> > > Ultimately, we concluded that a better course of action is to introduce
> > > a new security hook for LSM authors. [3]
> > >
> > > This patch set first introduces a new security_create_user_ns() function
> > > and userns_create LSM hook, then marks the hook as sleepable in BPF.
> > Patch 1 and 4 still need review from the lsm/security side.
>
>
> This patchset is in my review queue and assuming everything checks out, I expect to merge it after the upcoming merge window closes.
>
> I would also need an ACK from the BPF LSM folks, but they're CC'd on this patchset.

Based on last weeks comments, should I go ahead and put up v4 for 
5.20-rc1 when that drops, or do I need to wait for more feedback?

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> paul-moore.com