Subject: Re: bpf pointer alignment validation

From: Daniel Borkmann <[email-masked]>
Date: Mon, 08 May 2017 12:49:25 +0200

On 05/06/2017 04:47 AM, David Miller wrote:
> From: David Miller <[email-masked]>
> Date: Fri, 05 May 2017 16:20:44 -0400 (EDT)
>
>> Anyways, I'll play with this design and see what happens...
>> Feedback is of course welcome.
>
> Here is a prototype that works for me with test_pkt_access.c,
> which otherwise won't load on sparc.

Code looks good to me as far as I can tell, thanks for working
on this.

Could you also add test cases specifically to this for test_verifier
in bpf selftests? I'm thinking of the cases when we have no pkt id
and offset originated from reg->off (accumulated through const imm
ops on reg) and insn->off, where we had i) no pkt id and ii) a
specific pkt id (so we can probe for aux_off_align rejection as well).
I believe we do have coverage to some extend in some of the tests
(more on the map_value_adj though), but it would be good to keep
tracking this specifically as well.

Thanks a lot,
Daniel