netdev - Re: [PATCH net-next] bpf: add test for the verifier equal logic bug

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Message-ID: <583DD1C0.1010209@iogearbox.net>
Date:   Tue, 29 Nov 2016 20:06:40 +0100
From:   Daniel Borkmann <daniel@...earbox.net>
To:     Josef Bacik <jbacik@...com>, davem@...emloft.net,
        netdev@...r.kernel.org, ast@...nel.org, jannh@...gle.com,
        kernel-team@...com
Subject: Re: [PATCH net-next] bpf: add test for the verifier equal logic bug

On 11/29/2016 06:35 PM, Josef Bacik wrote:
> This is a test to verify that
>
> bpf: fix states equal logic for varlen access
>
> actually fixed the problem.  The problem was if the register we added to our map
> register was UNKNOWN in both the false and true branches and the only thing that
> changed was the range then we'd incorrectly assume that the true branch was
> valid, which it really wasnt.  This tests this case and properly fails without
> my fix in place and passes with it in place.
>
> Signed-off-by: Josef Bacik <jbacik@...com>

Acked-by: Daniel Borkmann <daniel@...earbox.net>

Thanks a lot for the test case! They are always useful to have ... which
just reminds me: it seems we didn't add anything for f23cc643f9ba ("bpf:
fix range arithmetic for bpf map access"). ;-)