linux-kernel - Re: [PATCH v2 8/8] crypto/testmgr: Allocate only the required output size for hash tests

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Message-ID: <CALCETrWZuHmZHzOUVp4J9cw9ajfS2JVr0fLyV0tyoyybGkCBqA@mail.gmail.com>
Date:   Wed, 11 Jan 2017 23:52:03 -0800
From:   Andy Lutomirski <luto@...capital.net>
To:     Herbert Xu <herbert@...dor.apana.org.au>
Cc:     Andy Lutomirski <luto@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Network Development <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Linux Crypto Mailing List <linux-crypto@...r.kernel.org>,
        "Jason A. Donenfeld" <Jason@...c4.com>,
        Hannes Frederic Sowa <hannes@...essinduktion.org>,
        Alexei Starovoitov <alexei.starovoitov@...il.com>,
        Eric Dumazet <edumazet@...gle.com>,
        Eric Biggers <ebiggers3@...il.com>,
        Tom Herbert <tom@...bertland.com>,
        "David S. Miller" <davem@...emloft.net>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>
Subject: Re: [PATCH v2 8/8] crypto/testmgr: Allocate only the required output
 size for hash tests

On Wed, Jan 11, 2017 at 11:47 PM, Herbert Xu
<herbert@...dor.apana.org.au> wrote:
> Andy Lutomirski <luto@...nel.org> wrote:
>> There are some hashes (e.g. sha224) that have some internal trickery
>> to make sure that only the correct number of output bytes are
>> generated.  If something goes wrong, they could potentially overrun
>> the output buffer.
>>
>> Make the test more robust by allocating only enough space for the
>> correct output size so that memory debugging will catch the error if
>> the output is overrun.
>>
>> Tested by intentionally breaking sha224 to output all 256
>> internally-generated bits while running on KASAN.
>>
>> Cc: Ard Biesheuvel <ard.biesheuvel@...aro.org>
>> Cc: Herbert Xu <herbert@...dor.apana.org.au>
>> Signed-off-by: Andy Lutomirski <luto@...nel.org>
>
> This patch doesn't seem to depend on anything else in the series.
> Do you want me to take it separately?

Yes, please.  Its only relation to the rest of the series is that I
wanted to make sure that I didn't mess up sha224's finalization code.

--Andy