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crypto: xts: add interface for parallelized cipher implementations

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

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Jussi Kivilinna 2011-11-09 11:56:06 +08:00 committed by Herbert Xu
parent f9d2691fc9
commit ce0045561e
2 changed files with 100 additions and 2 deletions
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75
crypto/xts.c
View File

@ -21,11 +21,10 @@
#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <crypto/xts.h>
#include <crypto/b128ops.h>
#include <crypto/gf128mul.h>
#define XTS_BLOCK_SIZE 16
struct priv {
struct crypto_cipher *child;
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);
}
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)
{
struct crypto_cipher *cipher;

27
include/crypto/xts.h Normal file
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@ -0,0 +1,27 @@
#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 */