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From:   David Laight <David.Laight@ACULAB.COM>
To:     'Corentin Labbe' <clabbe@baylibre.com>,
        "arnd@arndb.de" <arnd@arndb.de>,
        "davem@davemloft.net" <davem@davemloft.net>,
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        "mripard@kernel.org" <mripard@kernel.org>,
        "wens@csie.org" <wens@csie.org>
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        <linux-arm-kernel@lists.infradead.org>,
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Subject: RE: [PATCH v3 2/7] crypto: sun4i-ss: checking sg length is not
 sufficient
Thread-Topic: [PATCH v3 2/7] crypto: sun4i-ss: checking sg length is not
 sufficient
Thread-Index: AQHWvCBry++55PgsQECGWrYMz9WH2qnK16lg
Date:   Mon, 16 Nov 2020 14:54:58 +0000
Message-ID: <0a9e713557104048b535958b5fe6cb10@AcuMS.aculab.com>
References: <20201116135345.11834-1-clabbe@baylibre.com>
 <20201116135345.11834-3-clabbe@baylibre.com>
In-Reply-To: <20201116135345.11834-3-clabbe@baylibre.com>
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From: Corentin Labbe
> Sent: 16 November 2020 13:54
> 
> The optimized cipher function need length multiple of 4 bytes.
> But it get sometimes odd length.
> This is due to SG data could be stored with an offset.
> 
> So the fix is to check also if the offset is aligned with 4 bytes.
> Fixes: 6298e948215f2 ("crypto: sunxi-ss - Add Allwinner Security System crypto accelerator")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
> ---
>  drivers/crypto/allwinner/sun4i-ss/sun4i-ss-cipher.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/crypto/allwinner/sun4i-ss/sun4i-ss-cipher.c b/drivers/crypto/allwinner/sun4i-
> ss/sun4i-ss-cipher.c
> index 19f1aa577ed4..4dd736ee5a4d 100644
> --- a/drivers/crypto/allwinner/sun4i-ss/sun4i-ss-cipher.c
> +++ b/drivers/crypto/allwinner/sun4i-ss/sun4i-ss-cipher.c
> @@ -186,12 +186,12 @@ static int sun4i_ss_cipher_poll(struct skcipher_request *areq)
>  	 * we can use the SS optimized function
>  	 */
>  	while (in_sg && no_chunk == 1) {
> -		if (in_sg->length % 4)
> +		if (in_sg->length % 4 || !IS_ALIGNED(in_sg->offset, sizeof(u32)))

You probably ought to do the test in a consistent manner.
Probably something that reduces to:
	((unsigned long)in_sg->offset | in_sg->length) & 3u

	David

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