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From: Sowmini Varadhan <sowmini.varadhan@oracle.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: dhowells@redhat.com, linux-crypto@vger.kernel.org,
	"David S. Miller" <davem@davemloft.net>
Subject: Re: unaligned access in pkcs7_verify
Date: Mon, 12 Oct 2015 09:46:27 -0400	[thread overview]
Message-ID: <20151012134627.GG14646@oracle.com> (raw)
In-Reply-To: <20151012133209.GA27746@gondor.apana.org.au>

On (10/12/15 21:32), Herbert Xu wrote:
> Thanks.  We have two bugs here.  First of all pkcs7_verify definitely
> shouldn't place the structure after the digest without aligning the
> pointer.  So something like your patch is needed (but please use
> alignof instead of sizeof).  Also don't put in digest_size but
> instead align the pointer like
> 
> 	desc = PTR_ALIGN(digest + digest_size, ...)

That patch might not be rock-solid by itself though.  I was seeing
some panics/crashes when I was running with that patch, so I backed 
it off temporarily - should sinfo->sig.digest_size be set to the aligned
value?

> The sparc sha algorithms themselves need to declare the alignment
> that they require.  Currently they claim to be able to handle any
> alignment which appears to not be the case.

How would one do that correctly? I'm not a crypto expert, but I can
help test the patch..

--Sowmini

  reply	other threads:[~2015-10-12 13:46 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-02 14:00 unaligned access in pkcs7_verify Sowmini Varadhan
2015-10-08 13:15 ` Herbert Xu
2015-10-08 14:43   ` Sowmini Varadhan
2015-10-12 13:32     ` Herbert Xu
2015-10-12 13:46       ` Sowmini Varadhan [this message]
2015-10-12 14:06       ` David Miller
2015-10-13 13:39         ` Herbert Xu
2015-10-13 13:29       ` Sowmini Varadhan
2015-10-13 13:36         ` Herbert Xu

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