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From: ebiederm@xmission.com (Eric W. Biederman)
To: James Morris <jmorris@namei.org>
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Date: Fri, 25 May 2018 14:51:00 -0500
In-Reply-To: <alpine.LRH.2.21.1805260139030.11624@namei.org> (James Morris's
        message of "Sat, 26 May 2018 01:41:52 +1000 (AEST)")
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Subject: Re: [PATCH v3 1/7] security: rename security_kernel_read_file() hook
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James Morris <jmorris@namei.org> writes:

> On Thu, 24 May 2018, Eric W. Biederman wrote:
>
>> Below is where I suggest you start on sorting out these security hooks.
>> - Adding a security_kernel_arg to catch when you want to allow/deny the
>>   use of an argument to a syscall.  What security_kernel_file_read and
>>   security_kernel_file_post_read have been abused for.
>
> NAK. This abstraction is too semantically weak.
>
> LSM hooks need to map to stronger semantics so we can reason about what 
> the hook and the policy is supposed to be mediating.

I will take that as an extremely weak nack as all I did was expose the
existing code and what the code is currently doing.  I don't see how you
can NAK what is already being merged and used.

I will be happy to see a better proposal.

The best I can see is to take each and every syscall that my patch
is calling syscall_kernel_arg and make it it's own hook without an
enumeration.  I did not see any real duplication between the cases in my
enumeration so I don't think that will be a problem.  Maybe a bit of a
challenge for loadpin but otherwise not.

Thank you in this for understanding why I am having problems with the
current hook.

Eric