From: Herbert Xu <herbert@gondor.apana.org.au>
Subject: Re: unaligned access in pkcs7_verify
Date: Thu, 8 Oct 2015 21:15:19 +0800
Message-ID: <20151008131519.GA24362@gondor.apana.org.au>
References: <20151002140014.GI18263@oracle.com>
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Cc: dhowells@redhat.com, linux-crypto@vger.kernel.org
To: Sowmini Varadhan <sowmini.varadhan@oracle.com>
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On Fri, Oct 02, 2015 at 02:00:14PM +0000, Sowmini Varadhan wrote:
> 
> I'm getting a lot of unaligned access messages each time I 
> do "modprobe [-r] <module>" on sparc:
> 
> Kernel unaligned access at TPC[6ad9b4] pkcs7_verify+0x1ec/0x5e0
> Kernel unaligned access at TPC[6a5484] crypto_shash_finup+0xc/0x5c
> Kernel unaligned access at TPC[6a5390] crypto_shash_update+0xc/0x54
> Kernel unaligned access at TPC[10150308] sha1_sparc64_update+0x14/0x5c [sha1_sparc64]
> Kernel unaligned access at TPC[101501ac] __sha1_sparc64_update+0xc/0x98 [sha1_sparc64]
> 
> Looks like these are being caused by an unaligned desc at
> 
>         desc = digest + digest_size;
> 
> Doing this:
> 
> --- a/crypto/asymmetric_keys/pkcs7_verify.c
> +++ b/crypto/asymmetric_keys/pkcs7_verify.c
> @@ -46,7 +46,8 @@ static int pkcs7_digest(struct pkcs7_message *pkcs7,
>                 return (PTR_ERR(tfm) == -ENOENT) ? -ENOPKG : PTR_ERR(tfm);
>  
>         desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
> -       sinfo->sig.digest_size = digest_size = crypto_shash_digestsize(tfm);
> +       sinfo->sig.digest_size = digest_size = 
> +               ALIGN(crypto_shash_digestsize(tfm), sizeof (*desc));
>  
>         ret = -ENOMEM;
>         digest = kzalloc(digest_size + desc_size, GFP_KERNEL);
> 
> makes the unaliagned message go away, but I dont know if
> sinfo->sig.digest_size needs to be set to the (unaligned) raw 
> value of crypto_shash_digestsize() itself, and how to verify that
> this doesnt break something else in crypto

What hash algorithm were you using?

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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