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From:   "Eric W. Biederman" <ebiederm@xmission.com>
To:     Paul Moore <paul@paul-moore.com>
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Date:   Wed, 17 Aug 2022 14:57:40 -0500
In-Reply-To: <CAHC9VhSHJNLS-KJ-Rz1R12PQbqACSksLYLbymF78d5hMkSGc-g@mail.gmail.com>
        (Paul Moore's message of "Wed, 17 Aug 2022 12:01:39 -0400")
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Subject: Re: [PATCH v5 0/4] Introduce security_create_user_ns()
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Paul Moore <paul@paul-moore.com> writes:

> At the end of the v4 patchset I suggested merging this into lsm/next
> so it could get a full -rc cycle in linux-next, assuming no issues
> were uncovered during testing

What in the world can be uncovered in linux-next for code that has no in
tree users.

That is one of my largest problems.  I want to talk about the users and
the use cases and I don't get dialog.  Nor do I get hey look back there
you missed it.

Since you don't want to rehash this.  I will just repeat my conclusion
that the patchset appears to introduce an ineffective defense that will
achieve nothing in the defense of the kernel, and so all it will achieve
a code maintenance burden and to occasionally break legitimate users of
the user namespace.

Further the process is broken.  You are changing the semantics of an
operation with the introduction of a security hook.  That needs a
man-page and discussion on linux-abi.  In general of the scrutiny we
give to new systems and changed system calls.  As this change
fundamentally changes the semantics of creating a user namespace.

Skipping that part of the process is not simply disagree that is being
irresponsible.

Eric