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From: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
To: "Stephan Müller" <smueller@chronox.de>
Cc: herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org,
	Tianjia Zhang <tianjia.zhang@linux.alibaba.com>,
	ard.biesheuvel@linaro.org, nhorman@redhat.com, simo@redhat.com
Subject: Re: [PATCH v2 1/5] crypto: ECDH - check validity of Z before export
Date: Wed, 15 Jul 2020 10:17:03 -0300
Message-ID: <20200715131703.ig27p5f7thuf5gjr@valinor> (raw)
In-Reply-To: <4348752.LvFx2qVVIh@positron.chronox.de>


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Reviewed-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
Tested-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>

On Sun, Jul 12, 2020 at 06:39:26PM +0200, Stephan Müller wrote:
> SP800-56A rev3 section 5.7.1.2 step 2 mandates that the validity of the
> calculated shared secret is verified before the data is returned to the
> caller. Thus, the export function and the validity check functions are
> reversed. In addition, the sensitive variables of priv and rand_z are
> zeroized.
> 
> Signed-off-by: Stephan Mueller <smueller@chronox.de>
> ---
>  crypto/ecc.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/crypto/ecc.c b/crypto/ecc.c
> index 02d35be7702b..52e2d49262f2 100644
> --- a/crypto/ecc.c
> +++ b/crypto/ecc.c
> @@ -1495,11 +1495,16 @@ int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
>  
>  	ecc_point_mult(product, pk, priv, rand_z, curve, ndigits);
>  
> -	ecc_swap_digits(product->x, secret, ndigits);
> -
> -	if (ecc_point_is_zero(product))
> +	if (ecc_point_is_zero(product)) {
>  		ret = -EFAULT;
> +		goto err_validity;
> +	}
> +
> +	ecc_swap_digits(product->x, secret, ndigits);
>  
> +err_validity:
> +	memzero_explicit(priv, sizeof(priv));
> +	memzero_explicit(rand_z, sizeof(rand_z));
>  	ecc_free_point(product);
>  err_alloc_product:
>  	ecc_free_point(pk);
> -- 
> 2.26.2
> 
> 
> 
> 

-- 
Regards,
Marcelo


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  parent reply index

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-10 10:09 [PATCH 0/3] DH: SP800-56A rev 3 compliant shared secret Stephan Müller
2020-07-10 10:10 ` [PATCH 1/3] crypto: ECDH - check validity of Z before export Stephan Müller
2020-07-10 10:10 ` [PATCH 2/3] lib/mpi: Add mpi_sub_ui() Stephan Müller
2020-07-10 14:42   ` Ard Biesheuvel
2020-07-10 15:10     ` Stephan Mueller
2020-07-10 10:15 ` [PATCH 3/3] crypto: DH - check validity of Z before export Stephan Müller
2020-07-12 16:38 ` [PATCH v2 0/5] DH: SP800-56A rev 3 compliant validation checks Stephan Müller
2020-07-12 16:39   ` [PATCH v2 1/5] crypto: ECDH - check validity of Z before export Stephan Müller
2020-07-12 18:02     ` Vitaly Chikunov
2020-07-15 13:17     ` Marcelo Henrique Cerri [this message]
2020-07-12 16:39   ` [PATCH v2 2/5] lib/mpi: Add mpi_sub_ui() Stephan Müller
2020-07-16  7:30     ` Herbert Xu
2020-07-16  8:41       ` Ard Biesheuvel
2020-07-16 12:50         ` Marcelo Henrique Cerri
2020-07-16 13:09           ` Ard Biesheuvel
2020-07-16 13:41             ` Marcelo Henrique Cerri
2020-07-16 13:53               ` Ard Biesheuvel
2020-07-16 14:23                 ` Marcelo Henrique Cerri
2020-07-16 14:37                   ` Ard Biesheuvel
2020-07-16 14:56                     ` Marcelo Henrique Cerri
2020-07-16 15:20                       ` Ard Biesheuvel
2020-07-12 16:40   ` [PATCH v2 3/5] crypto: DH - check validity of Z before export Stephan Müller
2020-07-15 13:17     ` Marcelo Henrique Cerri
2020-07-12 16:40   ` [PATCH v2 4/5] crypto: DH SP800-56A rev 3 local public key validation Stephan Müller
2020-07-15 13:18     ` Marcelo Henrique Cerri
2020-07-12 16:42   ` [PATCH v2 5/5] crypto: ECDH " Stephan Müller
2020-07-12 18:06     ` Vitaly Chikunov
2020-07-13  5:04       ` Stephan Mueller
2020-07-13  5:59         ` Vitaly Chikunov
2020-07-13  6:02           ` Stephan Müller
2020-07-15 13:19     ` Marcelo Henrique Cerri
2020-07-20 17:05   ` [PATCH v3 0/5] DH: SP800-56A rev 3 compliant validation checks Stephan Müller
2020-07-20 17:07     ` [PATCH v3 1/5] crypto: ECDH - check validity of Z before export Stephan Müller
2020-07-22 13:11       ` Vitaly Chikunov
2020-07-24 17:47       ` Neil Horman
2020-07-20 17:08     ` [PATCH v3 2/5] lib/mpi: Add mpi_sub_ui() Stephan Müller
2020-07-20 17:08     ` [PATCH v3 3/5] crypto: DH - check validity of Z before export Stephan Müller
2020-07-24 18:02       ` Neil Horman
2020-07-20 17:08     ` [PATCH v3 4/5] crypto: DH SP800-56A rev 3 local public key validation Stephan Müller
2020-07-20 17:09     ` [PATCH v3 5/5] crypto: ECDH " Stephan Müller
2020-07-21 11:35     ` [PATCH v3 0/5] DH: SP800-56A rev 3 compliant validation checks Marcelo Henrique Cerri
2020-07-31 13:29     ` Herbert Xu

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