From: Herbert Xu <herbert@gondor.apana.org.au>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: Shreyansh Chouhan <chouhan.shreyansh630@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
X86 ML <x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
syzbot+20191dc583eff8602d2d@syzkaller.appspotmail.com
Subject: Re: [PATCH] crypto: xts_crypt() return if walk.nbytes is 0
Date: Fri, 20 Aug 2021 20:53:15 +0800 [thread overview]
Message-ID: <20210820125315.GB28484@gondor.apana.org.au> (raw)
In-Reply-To: <CAMj1kXGMPimX0_dR_kLuzZjuJK9rM=uCpRDtoJq0UjWq12M10A@mail.gmail.com>
On Fri, Aug 20, 2021 at 01:14:52PM +0200, Ard Biesheuvel wrote:
>
> In spite of that, I have a slight preference for this version, given
> that it makes it obvious that we bail on two separate conditions:
> - an error has occurred
> - no error has occurred but the resulting walk is empty
>
> Testing walk.nbytes only needlessly obfuscates the code, as we need to
> return 'err' in the end anyway.
I disagree, this is how most skcipher walkers are structured, they
never explicitly test on err and only terminate the loop when
walk->nbytes hits zero, in which case err is returned as is.
I don't see why this particular skcipher walker should deviate
from that paradigm. In fact it is exactly that deviation that
caused the bug in the first instance.
Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
next prev parent reply other threads:[~2021-08-20 12:53 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-30 13:41 [PATCH] crypto: add missing kernel_fpu_end() call Shreyansh Chouhan
2021-08-06 8:23 ` Herbert Xu
2021-08-06 9:05 ` Ard Biesheuvel
2021-08-06 9:07 ` Ard Biesheuvel
2021-08-06 10:36 ` Shreyansh Chouhan
2021-08-09 14:10 ` [PATCH] crypto: xts_crypt() return if walk.nbytes is 0 Shreyansh Chouhan
2021-08-17 14:18 ` Ard Biesheuvel
2021-08-20 8:31 ` Herbert Xu
2021-08-20 11:14 ` Ard Biesheuvel
2021-08-20 12:53 ` Herbert Xu [this message]
2021-08-22 3:45 ` [PATCH v2] " Shreyansh Chouhan
2021-08-27 8:38 ` Herbert Xu
2021-08-22 3:48 ` [PATCH] " Shreyansh Chouhan
2021-08-22 13:23 ` Ard Biesheuvel
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