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Commit ce004556 authored by Jussi Kivilinna's avatar Jussi Kivilinna Committed by Herbert Xu
Browse files

crypto: xts: add interface for parallelized cipher implementations 



Add xts_crypt() function that can be used by cipher implementations that can
benefit from parallelized cipher operations.

Signed-off-by: default avatarJussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent f9d2691f

crypto/xts.c

+73 −2
Original line number Original line Diff line number Diff line
@@ -21,11 +21,10 @@ 
#include <linux/scatterlist.h>

#include <linux/scatterlist.h>

#include <linux/slab.h>

#include <linux/slab.h>





#include <crypto/xts.h>

#include <crypto/b128ops.h>

#include <crypto/b128ops.h>

#include <crypto/gf128mul.h>

#include <crypto/gf128mul.h>





#define XTS_BLOCK_SIZE 16



struct priv {

struct priv {

	struct crypto_cipher *child;

	struct crypto_cipher *child;

	struct crypto_cipher *tweak;

	struct crypto_cipher *tweak;
@@ -167,6 +166,78 @@ static int decrypt(struct blkcipher_desc *desc, struct scatterlist *dst, 
		     crypto_cipher_alg(ctx->child)->cia_decrypt);

		     crypto_cipher_alg(ctx->child)->cia_decrypt);

}

}





int xts_crypt(struct blkcipher_desc *desc, struct scatterlist *sdst,

	      struct scatterlist *ssrc, unsigned int nbytes,

	      struct xts_crypt_req *req)

{

	const unsigned int bsize = XTS_BLOCK_SIZE;

	const unsigned int max_blks = req->tbuflen / bsize;

	struct blkcipher_walk walk;

	unsigned int nblocks;

	be128 *src, *dst, *t;

	be128 *t_buf = req->tbuf;

	int err, i;



	BUG_ON(max_blks < 1);



	blkcipher_walk_init(&walk, sdst, ssrc, nbytes);



	err = blkcipher_walk_virt(desc, &walk);

	nbytes = walk.nbytes;

	if (!nbytes)

		return err;



	nblocks = min(nbytes / bsize, max_blks);

	src = (be128 *)walk.src.virt.addr;

	dst = (be128 *)walk.dst.virt.addr;



	/* calculate first value of T */

	req->tweak_fn(req->tweak_ctx, (u8 *)&t_buf[0], walk.iv);



	i = 0;

	goto first;



	for (;;) {

		do {

			for (i = 0; i < nblocks; i++) {

				gf128mul_x_ble(&t_buf[i], t);

first:

				t = &t_buf[i];



				/* PP <- T xor P */

				be128_xor(dst + i, t, src + i);

			}



			/* CC <- E(Key2,PP) */

			req->crypt_fn(req->crypt_ctx, (u8 *)dst,

				      nblocks * bsize);



			/* C <- T xor CC */

			for (i = 0; i < nblocks; i++)

				be128_xor(dst + i, dst + i, &t_buf[i]);



			src += nblocks;

			dst += nblocks;

			nbytes -= nblocks * bsize;

			nblocks = min(nbytes / bsize, max_blks);

		} while (nblocks > 0);



		*(be128 *)walk.iv = *t;



		err = blkcipher_walk_done(desc, &walk, nbytes);

		nbytes = walk.nbytes;

		if (!nbytes)

			break;



		nblocks = min(nbytes / bsize, max_blks);

		src = (be128 *)walk.src.virt.addr;

		dst = (be128 *)walk.dst.virt.addr;

	}



	return err;

}

EXPORT_SYMBOL_GPL(xts_crypt);



static int init_tfm(struct crypto_tfm *tfm)

static int init_tfm(struct crypto_tfm *tfm)

{

{

	struct crypto_cipher *cipher;

	struct crypto_cipher *cipher;

include/crypto/xts.h

0 → 100644
+27 −0
Original line number Original line Diff line number Diff line 
#ifndef _CRYPTO_XTS_H

#define _CRYPTO_XTS_H



#include <crypto/b128ops.h>



struct scatterlist;

struct blkcipher_desc;



#define XTS_BLOCK_SIZE 16



struct xts_crypt_req {

	be128 *tbuf;

	unsigned int tbuflen;



	void *tweak_ctx;

	void (*tweak_fn)(void *ctx, u8* dst, const u8* src);

	void *crypt_ctx;

	void (*crypt_fn)(void *ctx, u8 *blks, unsigned int nbytes);

};



#define XTS_TWEAK_CAST(x) ((void (*)(void *, u8*, const u8*))(x))



int xts_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,

	      struct scatterlist *src, unsigned int nbytes,

	      struct xts_crypt_req *req);



#endif  /* _CRYPTO_XTS_H */