From: Pascal Van Leeuwen <pvanleeuwen@insidesecure.com>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Herbert Xu <herbert@gondor.apana.org.au>
Cc: Iuliana Prodan <iuliana.prodan@nxp.com>,
Eric Biggers <ebiggers@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Horia Geanta <horia.geanta@nxp.com>,
Sascha Hauer <s.hauer@pengutronix.de>,
"open list:HARDWARE RANDOM NUMBER GENERATOR CORE"
<linux-crypto@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
dl-linux-imx <linux-imx@nxp.com>
Subject: RE: [PATCH] crypto: gcm - fix cacheline sharing
Date: Thu, 30 May 2019 14:53:56 +0000 [thread overview]
Message-ID: <AM6PR09MB3523A665C9D9334659F05F90D2180@AM6PR09MB3523.eurprd09.prod.outlook.com> (raw)
In-Reply-To: <CAKv+Gu-KBgiyNY2Dypx6vqtmpTXNfOxxWxJf50BTiF2rCOFqnw@mail.gmail.com>
>
> This might work:
>
> diff --git a/drivers/crypto/caam/caamalg.c b/drivers/crypto/caam/caamalg.c
> index c0ece44f303b..3d313d2a279a 100644
> --- a/drivers/crypto/caam/caamalg.c
> +++ b/drivers/crypto/caam/caamalg.c
> @@ -1661,7 +1661,8 @@ static int aead_decrypt(struct aead_request *req)
> * allocate and map the skcipher extended descriptor for skcipher
> */
> static struct skcipher_edesc *skcipher_edesc_alloc(struct
> skcipher_request *req,
> - int desc_bytes)
> + int desc_bytes,
> + u8 const *input_iv)
> {
> struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
> struct caam_ctx *ctx = crypto_skcipher_ctx(skcipher);
> @@ -1745,7 +1746,7 @@ static struct skcipher_edesc
> *skcipher_edesc_alloc(struct skcipher_request *req,
> /* Make sure IV is located in a DMAable area */
> if (ivsize) {
> iv = (u8 *)edesc->hw_desc + desc_bytes + sec4_sg_bytes;
> - memcpy(iv, req->iv, ivsize);
> + memcpy(iv, input_iv, ivsize);
>
> iv_dma = dma_map_single(jrdev, iv, ivsize, DMA_TO_DEVICE);
> if (dma_mapping_error(jrdev, iv_dma)) {
> @@ -1801,7 +1802,8 @@ static int skcipher_encrypt(struct skcipher_request
> *req)
> int ret = 0;
>
> /* allocate extended descriptor */
> - edesc = skcipher_edesc_alloc(req, DESC_JOB_IO_LEN * CAAM_CMD_SZ);
> + edesc = skcipher_edesc_alloc(req, DESC_JOB_IO_LEN * CAAM_CMD_SZ,
> + req->iv);
> if (IS_ERR(edesc))
> return PTR_ERR(edesc);
>
> @@ -1832,13 +1834,11 @@ static int skcipher_decrypt(struct
> skcipher_request *req)
> struct caam_ctx *ctx = crypto_skcipher_ctx(skcipher);
> int ivsize = crypto_skcipher_ivsize(skcipher);
> struct device *jrdev = ctx->jrdev;
> + u8 in_iv[AES_BLOCK_SIZE];
> u32 *desc;
> int ret = 0;
>
> - /* allocate extended descriptor */
> - edesc = skcipher_edesc_alloc(req, DESC_JOB_IO_LEN * CAAM_CMD_SZ);
> - if (IS_ERR(edesc))
> - return PTR_ERR(edesc);
> + memcpy(in_iv, req->iv, ivsize);
>
> /*
> * The crypto API expects us to set the IV (req->iv) to the last
> @@ -1848,6 +1848,11 @@ static int skcipher_decrypt(struct skcipher_request
> *req)
> scatterwalk_map_and_copy(req->iv, req->src, req->cryptlen
> -
> ivsize, ivsize, 0);
>
> + /* allocate extended descriptor */
> + edesc = skcipher_edesc_alloc(req, DESC_JOB_IO_LEN * CAAM_CMD_SZ,
> in_iv);
> + if (IS_ERR(edesc))
> + return PTR_ERR(edesc);
> +
> /* Create and submit job descriptor*/
> init_skcipher_job(req, edesc, false);
> desc = edesc->hw_desc;
Interesting. This discussion made me reevaluate my own implementation.
First thing I realised is that I *am* currently doing the IV copying with
the data buffer mapped for DMA ... If I understand correctly that may be a
bad idea on some systems? I which case I will need to do my copy earlier.
Second thing is the above implementation made me realise I don't need to
buffer the IV as part of the skcipher_request_ctx, I can just copy the
original req->iv to some local variable, pass a pointer to that along and
then overwrite req->iv directly. More elegant and hopefully also more
efficient ...
Regards,
Pascal van Leeuwen
Silicon IP Architect, Multi-Protocol Engines
www.insidesecure.com
next prev parent reply other threads:[~2019-05-30 14:54 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-29 17:10 [PATCH] crypto: gcm - fix cacheline sharing Iuliana Prodan
2019-05-29 20:27 ` Eric Biggers
2019-05-29 22:16 ` Ard Biesheuvel
2019-05-30 13:29 ` Iuliana Prodan
2019-05-30 13:34 ` Herbert Xu
2019-05-30 13:45 ` Iuliana Prodan
2019-05-30 13:53 ` Ard Biesheuvel
2019-05-30 13:55 ` Ard Biesheuvel
2019-05-30 14:27 ` Herbert Xu
2019-05-30 14:28 ` Ard Biesheuvel
2019-05-30 14:31 ` Ard Biesheuvel
2019-05-30 14:34 ` Herbert Xu
2019-05-30 15:04 ` Ard Biesheuvel
2019-05-30 15:06 ` Herbert Xu
2019-05-30 15:10 ` Ard Biesheuvel
2019-05-30 15:13 ` Herbert Xu
2019-05-30 15:17 ` Ard Biesheuvel
2019-05-30 22:00 ` Iuliana Prodan
2019-05-31 5:54 ` Horia Geanta
2019-05-30 14:53 ` Pascal Van Leeuwen [this message]
2019-05-30 15:13 ` Ard Biesheuvel
2019-06-06 6:37 ` Herbert Xu
2019-06-06 6:42 ` Ard Biesheuvel
2019-06-06 6:46 ` Herbert Xu
2019-06-06 6:53 ` Ard Biesheuvel
2019-06-06 6:57 ` Herbert Xu
2019-06-06 7:10 ` Horia Geanta
2019-06-06 7:15 ` Herbert Xu
2019-06-06 8:36 ` Horia Geanta
2019-06-06 9:33 ` Herbert Xu
2019-05-30 13:58 ` Herbert Xu
2019-05-30 14:11 ` Ard Biesheuvel
2019-05-30 14:29 ` Pascal Van Leeuwen
2019-05-30 5:34 ` Herbert Xu
2019-05-30 7:46 ` Horia Geanta
2019-05-30 8:08 ` Ard Biesheuvel
2019-05-30 13:18 ` Horia Geanta
2019-05-30 13:25 ` Ard Biesheuvel
2019-05-31 6:05 ` Horia Geanta
2019-05-30 13:26 ` Herbert Xu
2019-05-31 5:22 ` Horia Geanta
2019-05-31 5:42 ` Herbert Xu
2019-05-31 6:10 ` Horia Geanta
2019-05-31 6:14 ` Herbert Xu
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