From: Andy Lutomirski <luto@amacapital.net>
To: David Laight <David.Laight@aculab.com>
Cc: Andy Lutomirski <luto@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Netdev <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
"Jason A. Donenfeld" <Jason@zx2c4.com>,
Hannes Frederic Sowa <hannes@stressinduktion.org>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Eric Dumazet <edumazet@google.com>,
Eric Biggers <ebiggers3@gmail.com>,
Tom Herbert <tom@herbertland.com>,
"David S. Miller" <davem@davemloft.net>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Herbert Xu <herbert@gondor.apana.org.au>
Subject: Re: [PATCH v2 8/8] crypto/testmgr: Allocate only the required output size for hash tests
Date: Wed, 11 Jan 2017 10:10:27 -0800 [thread overview]
Message-ID: <CALCETrX_8_sbGgc4N8opSnXimnZNp5HbTvdonnHoFic8b_Zp-A@mail.gmail.com> (raw)
In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6DB025EE7B@AcuExch.aculab.com>
On Wed, Jan 11, 2017 at 7:13 AM, David Laight <David.Laight@aculab.com> wrote:
> From: Andy Lutomirski
>> Sent: 10 January 2017 23:25
>> 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.
>
> Might be better to test this by allocating an overlong buffer
> and then explicitly checking that the output hasn't overrun
> the allowed space.
>
> If nothing else the error message will be clearer.
I thought about that, but then I'd have to figure out what poison
value to use. Both KASAN and the usual slab debugging are quite good
at this kind of checking, and KASAN will even point you to the
problematic code directly.
--Andy
--
Andy Lutomirski
AMA Capital Management, LLC
next prev parent reply other threads:[~2017-01-11 18:10 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-10 23:24 [PATCH v2 0/8] Switch BPF's digest to SHA256 Andy Lutomirski
2017-01-10 23:24 ` [PATCH v2 1/8] crypto/sha256: Factor out the parts of base API that don't use shash_desc Andy Lutomirski
2017-01-10 23:24 ` [PATCH v2 2/8] crypto/sha256: Export a sha256_{init,update,final}_direct() API Andy Lutomirski
2017-01-10 23:24 ` [PATCH v2 3/8] crypto/sha256: Build the SHA256 core separately from the crypto module Andy Lutomirski
2017-01-10 23:24 ` [PATCH v2 4/8] bpf: Use SHA256 instead of SHA1 for bpf digests Andy Lutomirski
2017-01-10 23:24 ` [PATCH v2 5/8] bpf: Avoid copying the entire BPF program when hashing it Andy Lutomirski
2017-01-10 23:24 ` [PATCH v2 6/8] bpf: Rename fdinfo's prog_digest to prog_sha256 Andy Lutomirski
2017-01-10 23:24 ` [PATCH v2 7/8] net: Rename TCA*BPF_DIGEST to ..._SHA256 Andy Lutomirski
2017-01-11 0:50 ` Daniel Borkmann
2017-01-11 3:11 ` Andy Lutomirski
2017-01-11 9:09 ` Daniel Borkmann
2017-01-11 18:19 ` Andy Lutomirski
2017-01-13 23:08 ` Daniel Borkmann
2017-01-10 23:24 ` [PATCH v2 8/8] crypto/testmgr: Allocate only the required output size for hash tests Andy Lutomirski
2017-01-11 15:13 ` David Laight
2017-01-11 18:10 ` Andy Lutomirski [this message]
2017-01-12 7:47 ` Herbert Xu
2017-01-12 7:52 ` Andy Lutomirski
2017-01-12 16:44 ` Herbert Xu
2017-01-11 1:09 ` [PATCH v2 0/8] Switch BPF's digest to SHA256 Alexei Starovoitov
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