netdev - Re: [PATCH net] bpf: rework prog_digest into prog

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CALCETrWD7FuRLH0dC46bMf85mXosC3r54=TAXdar5EsZvbvyzg@mail.gmail.com>
Date:   Fri, 13 Jan 2017 15:49:55 -0800
From:   Andy Lutomirski <luto@...capital.net>
To:     Daniel Borkmann <daniel@...earbox.net>
Cc:     "David S. Miller" <davem@...emloft.net>,
        Alexei Starovoitov <alexei.starovoitov@...il.com>,
        Andrew Lutomirski <luto@...nel.org>,
        Network Development <netdev@...r.kernel.org>
Subject: Re: [PATCH net] bpf: rework prog_digest into prog_tag

On Fri, Jan 13, 2017 at 3:41 PM, Daniel Borkmann <daniel@...earbox.net> wrote:
> On 01/14/2017 12:16 AM, Andy Lutomirski wrote:
>>
>> On Fri, Jan 13, 2017 at 2:38 PM, Daniel Borkmann <daniel@...earbox.net>
>> wrote:
>>>
>>> Commit 7bd509e311f4 ("bpf: add prog_digest and expose it via
>>> fdinfo/netlink") was recently discussed, partially due to
>>> admittedly suboptimal name of "prog_digest" in combination
>>> with sha1 hash usage, thus inevitably and rightfully concerns
>>> about its security in terms of collision resistance were
>>> raised with regards to use-cases.
>>
>>
>> Seems reasonable.  My only question is whether you'd still want to
>> switch to SHA-256 just from a code cleanliness perspective.  With
>> SHA-256 you can use the easy streaming API I wrote, but with SHA-1
>> you're still stuck with the crappy API in lib/, and I'm not
>> volunteering to fix up the SHA-1 API.
>
>
> We'd need to truncate that in kernel anyway to not get a too long
> tag, so given that I'm actually fine with it as-is. I was planning
> to submit the code for testing to bpf selftests for net-next once
> it's merged back, too.

Unless you want to kill off that vmalloc()+vfree() pair...

--Andy