Re: [PATCH 2/2] crypto: vmx - Adding support for XTS

[Stephan Mueller]

Am Montag, 11. Juli 2016, 16:07:40 CEST schrieb Paulo Flabiano Smorigo:

Hi Paulo,

> From: "Leonidas S. Barbosa" <leosilva@xxxxxxxxxxxxxxxxxx>
> 
> This patch add XTS support using VMX-crypto driver.
> 
> Signed-off-by: Leonidas S. Barbosa <leosilva@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Paulo Flabiano Smorigo <pfsmorigo@xxxxxxxxxxxxxxxxxx>
> ---
>  drivers/crypto/vmx/Makefile  |   2 +-
>  drivers/crypto/vmx/aes_xts.c | 187
> +++++++++++++++++++++++++++++++++++++++++++ drivers/crypto/vmx/vmx.c     | 
>  2 +
>  3 files changed, 190 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/crypto/vmx/aes_xts.c
> 
> diff --git a/drivers/crypto/vmx/Makefile b/drivers/crypto/vmx/Makefile
> index d28ab96..de6e241 100644
> --- a/drivers/crypto/vmx/Makefile
> +++ b/drivers/crypto/vmx/Makefile
> @@ -1,5 +1,5 @@
>  obj-$(CONFIG_CRYPTO_DEV_VMX_ENCRYPT) += vmx-crypto.o
> -vmx-crypto-objs := vmx.o aesp8-ppc.o ghashp8-ppc.o aes.o aes_cbc.o
> aes_ctr.o ghash.o +vmx-crypto-objs := vmx.o aesp8-ppc.o ghashp8-ppc.o aes.o
> aes_cbc.o aes_ctr.o aes_xts.o ghash.o
> 
>  ifeq ($(CONFIG_CPU_LITTLE_ENDIAN),y)
>  TARGET := linux-ppc64le
> diff --git a/drivers/crypto/vmx/aes_xts.c b/drivers/crypto/vmx/aes_xts.c
> new file mode 100644
> index 0000000..62e698c
> --- /dev/null
> +++ b/drivers/crypto/vmx/aes_xts.c
> @@ -0,0 +1,187 @@
> +/**
> + * AES XTS routines supporting VMX In-core instructions on Power 8
> + *
> + * Copyright (C) 2015 International Business Machines Inc.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundations; version 2 only.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY of FITNESS FOR A PARTICUPAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
> + *
> + * Author: Leonidas S. Barbosa <leosilva@xxxxxxxxxxxxxxxxxx>
> + */
> +
> +#include <linux/types.h>
> +#include <linux/err.h>
> +#include <linux/crypto.h>
> +#include <linux/delay.h>
> +#include <linux/hardirq.h>
> +#include <asm/switch_to.h>
> +#include <crypto/aes.h>
> +#include <crypto/scatterwalk.h>
> +
> +#include "aesp8-ppc.h"
> +
> +struct p8_aes_xts_ctx {
> +	struct crypto_blkcipher *fallback;
> +	struct aes_key enc_key;
> +	struct aes_key dec_key;
> +	struct aes_key tweak_key;
> +};
> +
> +static int p8_aes_xts_init(struct crypto_tfm *tfm)
> +{
> +	const char *alg;
> +	struct crypto_blkcipher *fallback;
> +	struct p8_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);
> +
> +	if (!(alg = crypto_tfm_alg_name(tfm))) {
> +		printk(KERN_ERR "Failed to get algorithm name.\n");
> +		return -ENOENT;
> +	}
> +
> +	fallback =
> +		crypto_alloc_blkcipher(alg, 0, CRYPTO_ALG_NEED_FALLBACK);
> +	if (IS_ERR(fallback)) {
> +		printk(KERN_ERR
> +			"Failed to allocate transformation for '%s': %ld\n",
> +			alg, PTR_ERR(fallback));
> +		return PTR_ERR(fallback);
> +	}
> +	printk(KERN_INFO "Using '%s' as fallback implementation.\n",
> +		crypto_tfm_alg_driver_name((struct crypto_tfm *) fallback));
> +
> +	crypto_blkcipher_set_flags(
> +		fallback,
> +		crypto_blkcipher_get_flags((struct crypto_blkcipher *)tfm));
> +	ctx->fallback = fallback;
> +
> +	return 0;
> +}
> +
> +static void p8_aes_xts_exit(struct crypto_tfm *tfm)
> +{
> +	struct p8_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);
> +
> +	if (ctx->fallback) {
> +		crypto_free_blkcipher(ctx->fallback);
> +		ctx->fallback = NULL;
> +	}
> +}
> +
> +static int p8_aes_xts_setkey(struct crypto_tfm *tfm, const u8 *key,
> +			     unsigned int keylen)
> +{
> +	int ret;
> +	struct p8_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);
> +
> +	if (keylen % 2)
> +		return -EINVAL;

Please use xts_check_key instead of this check.
> +
> +	preempt_disable();
> +	pagefault_disable();
> +	enable_kernel_vsx();
> +	ret = aes_p8_set_encrypt_key(key + keylen/2, (keylen/2) * 8,
> &ctx->tweak_key); +	ret += aes_p8_set_encrypt_key(key, (keylen/2) * 8,
> &ctx->enc_key); +	ret += aes_p8_set_decrypt_key(key, (keylen/2) * 8,
> &ctx->dec_key); +	disable_kernel_vsx();
> +	pagefault_enable();
> +	preempt_enable();
> +
> +	ret += crypto_blkcipher_setkey(ctx->fallback, key, keylen);
> +	return ret;
> +}
> +
> +static int p8_aes_xts_crypt(struct blkcipher_desc *desc,
> +			    struct scatterlist *dst,
> +			    struct scatterlist *src,
> +			    unsigned int nbytes, int enc)
> +{
> +	int ret;
> +	u8 tweak[AES_BLOCK_SIZE];
> +	u8 *iv;
> +	struct blkcipher_walk walk;
> +	struct p8_aes_xts_ctx *ctx =
> +		crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm));
> +	struct blkcipher_desc fallback_desc = {
> +		.tfm = ctx->fallback,
> +		.info = desc->info,
> +		.flags = desc->flags
> +	};
> +
> +	if (in_interrupt()) {
> +		ret = enc ? crypto_blkcipher_encrypt(&fallback_desc, dst, src, nbytes) 
:
> +                            crypto_blkcipher_decrypt(&fallback_desc, dst,
> src, nbytes); +	} else {
> +		preempt_disable();
> +		pagefault_disable();
> +		enable_kernel_vsx();
> +
> +		blkcipher_walk_init(&walk, dst, src, nbytes);
> +
> +		iv = (u8 *)walk.iv;
> +		ret = blkcipher_walk_virt(desc, &walk);
> +		aes_p8_encrypt(iv, tweak, &ctx->tweak_key);
> +
> +		while ((nbytes = walk.nbytes)) {
> +			if (enc)
> +				aes_p8_xts_encrypt(walk.src.virt.addr, walk.dst.virt.addr,
> +						nbytes & AES_BLOCK_MASK, &ctx->enc_key, NULL, tweak);
> +			else
> +				aes_p8_xts_decrypt(walk.src.virt.addr, walk.dst.virt.addr,
> +						nbytes & AES_BLOCK_MASK, &ctx->dec_key, NULL, tweak);
> +
> +			nbytes &= AES_BLOCK_SIZE - 1;
> +			ret = blkcipher_walk_done(desc, &walk, nbytes);
> +		}
> +
> +		disable_kernel_vsx();
> +		pagefault_enable();
> +		preempt_enable();

memzero_explicit(tweak) ?
> +	}
> +	return ret;
> +}
> +
> +static int p8_aes_xts_encrypt(struct blkcipher_desc *desc,
> +			      struct scatterlist *dst,
> +			      struct scatterlist *src, unsigned int nbytes)
> +{
> +	return p8_aes_xts_crypt(desc, dst, src, nbytes, 1);
> +}
> +
> +static int p8_aes_xts_decrypt(struct blkcipher_desc *desc,
> +			      struct scatterlist *dst,
> +			      struct scatterlist *src, unsigned int nbytes)
> +{
> +	return p8_aes_xts_crypt(desc, dst, src, nbytes, 0);
> +}
> +
> +struct crypto_alg p8_aes_xts_alg = {
> +	.cra_name = "xts(aes)",
> +	.cra_driver_name = "p8_aes_xts",
> +	.cra_module = THIS_MODULE,
> +	.cra_priority = 2000,
> +	.cra_type = &crypto_blkcipher_type,
> +	.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK,
> +	.cra_alignmask = 0,
> +	.cra_blocksize = AES_BLOCK_SIZE,
> +	.cra_ctxsize = sizeof(struct p8_aes_xts_ctx),
> +	.cra_init = p8_aes_xts_init,
> +	.cra_exit = p8_aes_xts_exit,
> +	.cra_blkcipher = {
> +			.ivsize = AES_BLOCK_SIZE,
> +			.min_keysize = 2 * AES_MIN_KEY_SIZE,
> +			.max_keysize = 2 * AES_MAX_KEY_SIZE,
> +			.setkey	 = p8_aes_xts_setkey,
> +			.encrypt = p8_aes_xts_encrypt,
> +			.decrypt = p8_aes_xts_decrypt,
> +	}
> +};
> diff --git a/drivers/crypto/vmx/vmx.c b/drivers/crypto/vmx/vmx.c
> index e163d57..f688c32 100644
> --- a/drivers/crypto/vmx/vmx.c
> +++ b/drivers/crypto/vmx/vmx.c
> @@ -31,10 +31,12 @@ extern struct shash_alg p8_ghash_alg;
>  extern struct crypto_alg p8_aes_alg;
>  extern struct crypto_alg p8_aes_cbc_alg;
>  extern struct crypto_alg p8_aes_ctr_alg;
> +extern struct crypto_alg p8_aes_xts_alg;
>  static struct crypto_alg *algs[] = {
>  	&p8_aes_alg,
>  	&p8_aes_cbc_alg,
>  	&p8_aes_ctr_alg,
> +	&p8_aes_xts_alg,
>  	NULL,
>  };


Ciao
Stephan