From: David Howells <dhowells@redhat.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: dhowells@redhat.com, Andy Lutomirski <luto@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
USB list <linux-usb@vger.kernel.org>,
keyrings@vger.kernel.org, Eric Biggers <ebiggers3@gmail.com>,
linux-crypto@vger.kernel.org,
Herbert Xu <herbert@gondor.apana.org.au>,
Stephan Mueller <smueller@chronox.de>
Subject: Re: [PATCH v2] keys/encrypted: Fix two crypto-on-the-stack bugs
Date: Wed, 14 Dec 2016 08:37:59 +0000 [thread overview]
Message-ID: <18039.1481704679@warthog.procyon.org.uk> (raw)
In-Reply-To: <CALCETrX-YYp5iXPLKOpiT9+3DXYxGTVRXVyPN0oiYpQQC8kH3w@mail.gmail.com>
Andy Lutomirski <luto@amacapital.net> wrote:
> > - sg_set_buf(&sg_out[1], pad, sizeof pad);
> > + sg_set_buf(&sg_out[1], empty_zero_page, 16);
>
> My fix here is obviously bogus (I meant to use ZERO_PAGE(0)), but what
> exactly is the code trying to do? The old code makes no sense. It's
> setting the *output* buffer to zeroed padding.
Padding goes into the encrypt function and is going to come out of the decrypt
function. Possibly derived_key_decrypt() should be checking that the padding
that comes out is actually a bunch of zeros. Maybe we don't actually need to
get the padding out, but I'm not sure whether the crypto layer will
malfunction if we don't give it a buffer for the padding.
David
next prev parent reply other threads:[~2016-12-14 8:38 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-14 2:48 [PATCH v2] keys/encrypted: Fix two crypto-on-the-stack bugs Andy Lutomirski
2016-12-14 2:53 ` Andy Lutomirski
2016-12-14 5:04 ` Herbert Xu
2016-12-14 8:10 ` Eric Biggers
2016-12-14 8:37 ` David Howells [this message]
2016-12-14 16:22 ` Andy Lutomirski
2016-12-14 17:00 ` David Howells
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