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Date:   Fri, 28 Feb 2020 11:42:35 +1100
From:   Herbert Xu <herbert@gondor.apana.org.au>
To:     Horia =?utf-8?Q?Geant=C4=83?= <horia.geanta@nxp.com>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Aymen Sghaier <aymen.sghaier@nxp.com>,
        Valentin Ciocoi Radulescu <valentin.ciocoi@nxp.com>,
        linux-crypto@vger.kernel.org, NXP Linux Team <linux-imx@nxp.com>
Subject: Re: [PATCH] crypto: caam/qi2 - fix chacha20 data size error
Message-ID: <20200228004235.GB9163@gondor.apana.org.au>
References: <20200221075201.5725-1-horia.geanta@nxp.com>
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On Fri, Feb 21, 2020 at 09:52:01AM +0200, Horia Geantă wrote:
> HW generates a Data Size error for chacha20 requests that are not
> a multiple of 64B, since algorithm state (AS) does not have
> the FINAL bit set.
> 
> Since updating req->iv (for chaining) is not required,
> modify skcipher descriptors to set the FINAL bit for chacha20.
> 
> [Note that for skcipher decryption we know that ctx1_iv_off is 0,
> which allows for an optimization by not checking algorithm type,
> since append_dec_op1() sets FINAL bit for all algorithms except AES.]
> 
> Also drop the descriptor operations that save the IV.
> However, in order to keep code logic simple, things like
> S/G tables generation etc. are not touched.
> 
> Cc: <stable@vger.kernel.org> # v5.3+
> Fixes: 334d37c9e263 ("crypto: caam - update IV using HW support")
> Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
> ---
>  drivers/crypto/caam/caamalg_desc.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/crypto/caam/caamalg_desc.c b/drivers/crypto/caam/caamalg_desc.c
> index aa9ccca67045..372d3d4ed6c5 100644
> --- a/drivers/crypto/caam/caamalg_desc.c
> +++ b/drivers/crypto/caam/caamalg_desc.c
> @@ -1379,6 +1379,8 @@ void cnstr_shdsc_skcipher_encap(u32 * const desc, struct alginfo *cdata,
>  				const u32 ctx1_iv_off)
>  {
>  	u32 *key_jump_cmd;
> +	bool is_chacha20 = ((cdata->algtype & OP_ALG_ALGSEL_MASK) ==
> +			    OP_ALG_ALGSEL_CHACHA20);
>  
>  	init_sh_desc(desc, HDR_SHARE_SERIAL | HDR_SAVECTX);
>  	/* Skip if already shared */
> @@ -1417,14 +1419,15 @@ void cnstr_shdsc_skcipher_encap(u32 * const desc, struct alginfo *cdata,
>  				      LDST_OFFSET_SHIFT));
>  
>  	/* Load operation */
> -	append_operation(desc, cdata->algtype | OP_ALG_AS_INIT |
> -			 OP_ALG_ENCRYPT);
> +	if (is_chacha20)
> +		options |= OP_ALG_AS_FINALIZE;
> +	append_operation(desc, options);

This patch doesn't compile.

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