linux/crypto/lrw.c
Herbert Xu 700cb3f5fe crypto: lrw - Convert to skcipher
This patch converts lrw over to the skcipher interface.  It also
optimises the implementation to be based on ECB instead of the
underlying cipher.  For compatibility the existing naming scheme
of lrw(aes) is maintained as opposed to the more obvious one of
lrw(ecb(aes)).

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-11-28 21:23:17 +08:00

657 lines
15 KiB
C

/* LRW: as defined by Cyril Guyot in
* http://grouper.ieee.org/groups/1619/email/pdf00017.pdf
*
* Copyright (c) 2006 Rik Snel <rsnel@cube.dyndns.org>
*
* Based on ecb.c
* Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
*
* 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 Foundation; either version 2 of the License, or (at your option)
* any later version.
*/
/* This implementation is checked against the test vectors in the above
* document and by a test vector provided by Ken Buchanan at
* http://www.mail-archive.com/stds-p1619@listserv.ieee.org/msg00173.html
*
* The test vectors are included in the testing module tcrypt.[ch] */
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <crypto/b128ops.h>
#include <crypto/gf128mul.h>
#include <crypto/lrw.h>
#define LRW_BUFFER_SIZE 128u
struct priv {
struct crypto_skcipher *child;
struct lrw_table_ctx table;
};
struct rctx {
be128 buf[LRW_BUFFER_SIZE / sizeof(be128)];
be128 t;
be128 *ext;
struct scatterlist srcbuf[2];
struct scatterlist dstbuf[2];
struct scatterlist *src;
struct scatterlist *dst;
unsigned int left;
struct skcipher_request subreq;
};
static inline void setbit128_bbe(void *b, int bit)
{
__set_bit(bit ^ (0x80 -
#ifdef __BIG_ENDIAN
BITS_PER_LONG
#else
BITS_PER_BYTE
#endif
), b);
}
int lrw_init_table(struct lrw_table_ctx *ctx, const u8 *tweak)
{
be128 tmp = { 0 };
int i;
if (ctx->table)
gf128mul_free_64k(ctx->table);
/* initialize multiplication table for Key2 */
ctx->table = gf128mul_init_64k_bbe((be128 *)tweak);
if (!ctx->table)
return -ENOMEM;
/* initialize optimization table */
for (i = 0; i < 128; i++) {
setbit128_bbe(&tmp, i);
ctx->mulinc[i] = tmp;
gf128mul_64k_bbe(&ctx->mulinc[i], ctx->table);
}
return 0;
}
EXPORT_SYMBOL_GPL(lrw_init_table);
void lrw_free_table(struct lrw_table_ctx *ctx)
{
if (ctx->table)
gf128mul_free_64k(ctx->table);
}
EXPORT_SYMBOL_GPL(lrw_free_table);
static int setkey(struct crypto_skcipher *parent, const u8 *key,
unsigned int keylen)
{
struct priv *ctx = crypto_skcipher_ctx(parent);
struct crypto_skcipher *child = ctx->child;
int err, bsize = LRW_BLOCK_SIZE;
const u8 *tweak = key + keylen - bsize;
crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
CRYPTO_TFM_REQ_MASK);
err = crypto_skcipher_setkey(child, key, keylen - bsize);
crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &
CRYPTO_TFM_RES_MASK);
if (err)
return err;
return lrw_init_table(&ctx->table, tweak);
}
static inline void inc(be128 *iv)
{
be64_add_cpu(&iv->b, 1);
if (!iv->b)
be64_add_cpu(&iv->a, 1);
}
/* this returns the number of consequative 1 bits starting
* from the right, get_index128(00 00 00 00 00 00 ... 00 00 10 FB) = 2 */
static inline int get_index128(be128 *block)
{
int x;
__be32 *p = (__be32 *) block;
for (p += 3, x = 0; x < 128; p--, x += 32) {
u32 val = be32_to_cpup(p);
if (!~val)
continue;
return x + ffz(val);
}
return x;
}
static int post_crypt(struct skcipher_request *req)
{
struct rctx *rctx = skcipher_request_ctx(req);
be128 *buf = rctx->ext ?: rctx->buf;
struct skcipher_request *subreq;
const int bs = LRW_BLOCK_SIZE;
struct skcipher_walk w;
struct scatterlist *sg;
unsigned offset;
int err;
subreq = &rctx->subreq;
err = skcipher_walk_virt(&w, subreq, false);
while (w.nbytes) {
unsigned int avail = w.nbytes;
be128 *wdst;
wdst = w.dst.virt.addr;
do {
be128_xor(wdst, buf++, wdst);
wdst++;
} while ((avail -= bs) >= bs);
err = skcipher_walk_done(&w, avail);
}
rctx->left -= subreq->cryptlen;
if (err || !rctx->left)
goto out;
rctx->dst = rctx->dstbuf;
scatterwalk_done(&w.out, 0, 1);
sg = w.out.sg;
offset = w.out.offset;
if (rctx->dst != sg) {
rctx->dst[0] = *sg;
sg_unmark_end(rctx->dst);
scatterwalk_crypto_chain(rctx->dst, sg_next(sg), 0, 2);
}
rctx->dst[0].length -= offset - sg->offset;
rctx->dst[0].offset = offset;
out:
return err;
}
static int pre_crypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct rctx *rctx = skcipher_request_ctx(req);
struct priv *ctx = crypto_skcipher_ctx(tfm);
be128 *buf = rctx->ext ?: rctx->buf;
struct skcipher_request *subreq;
const int bs = LRW_BLOCK_SIZE;
struct skcipher_walk w;
struct scatterlist *sg;
unsigned cryptlen;
unsigned offset;
be128 *iv;
bool more;
int err;
subreq = &rctx->subreq;
skcipher_request_set_tfm(subreq, tfm);
cryptlen = subreq->cryptlen;
more = rctx->left > cryptlen;
if (!more)
cryptlen = rctx->left;
skcipher_request_set_crypt(subreq, rctx->src, rctx->dst,
cryptlen, req->iv);
err = skcipher_walk_virt(&w, subreq, false);
iv = w.iv;
while (w.nbytes) {
unsigned int avail = w.nbytes;
be128 *wsrc;
be128 *wdst;
wsrc = w.src.virt.addr;
wdst = w.dst.virt.addr;
do {
*buf++ = rctx->t;
be128_xor(wdst++, &rctx->t, wsrc++);
/* T <- I*Key2, using the optimization
* discussed in the specification */
be128_xor(&rctx->t, &rctx->t,
&ctx->table.mulinc[get_index128(iv)]);
inc(iv);
} while ((avail -= bs) >= bs);
err = skcipher_walk_done(&w, avail);
}
skcipher_request_set_tfm(subreq, ctx->child);
skcipher_request_set_crypt(subreq, rctx->dst, rctx->dst,
cryptlen, NULL);
if (err || !more)
goto out;
rctx->src = rctx->srcbuf;
scatterwalk_done(&w.in, 0, 1);
sg = w.in.sg;
offset = w.in.offset;
if (rctx->src != sg) {
rctx->src[0] = *sg;
sg_unmark_end(rctx->src);
scatterwalk_crypto_chain(rctx->src, sg_next(sg), 0, 2);
}
rctx->src[0].length -= offset - sg->offset;
rctx->src[0].offset = offset;
out:
return err;
}
static int init_crypt(struct skcipher_request *req, crypto_completion_t done)
{
struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
struct rctx *rctx = skcipher_request_ctx(req);
struct skcipher_request *subreq;
gfp_t gfp;
subreq = &rctx->subreq;
skcipher_request_set_callback(subreq, req->base.flags, done, req);
gfp = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL :
GFP_ATOMIC;
rctx->ext = NULL;
subreq->cryptlen = LRW_BUFFER_SIZE;
if (req->cryptlen > LRW_BUFFER_SIZE) {
subreq->cryptlen = min(req->cryptlen, (unsigned)PAGE_SIZE);
rctx->ext = kmalloc(subreq->cryptlen, gfp);
}
rctx->src = req->src;
rctx->dst = req->dst;
rctx->left = req->cryptlen;
/* calculate first value of T */
memcpy(&rctx->t, req->iv, sizeof(rctx->t));
/* T <- I*Key2 */
gf128mul_64k_bbe(&rctx->t, ctx->table.table);
return 0;
}
static void exit_crypt(struct skcipher_request *req)
{
struct rctx *rctx = skcipher_request_ctx(req);
rctx->left = 0;
if (rctx->ext)
kfree(rctx->ext);
}
static int do_encrypt(struct skcipher_request *req, int err)
{
struct rctx *rctx = skcipher_request_ctx(req);
struct skcipher_request *subreq;
subreq = &rctx->subreq;
while (!err && rctx->left) {
err = pre_crypt(req) ?:
crypto_skcipher_encrypt(subreq) ?:
post_crypt(req);
if (err == -EINPROGRESS ||
(err == -EBUSY &&
req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG))
return err;
}
exit_crypt(req);
return err;
}
static void encrypt_done(struct crypto_async_request *areq, int err)
{
struct skcipher_request *req = areq->data;
struct skcipher_request *subreq;
struct rctx *rctx;
rctx = skcipher_request_ctx(req);
subreq = &rctx->subreq;
subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
err = do_encrypt(req, err ?: post_crypt(req));
if (rctx->left)
return;
skcipher_request_complete(req, err);
}
static int encrypt(struct skcipher_request *req)
{
return do_encrypt(req, init_crypt(req, encrypt_done));
}
static int do_decrypt(struct skcipher_request *req, int err)
{
struct rctx *rctx = skcipher_request_ctx(req);
struct skcipher_request *subreq;
subreq = &rctx->subreq;
while (!err && rctx->left) {
err = pre_crypt(req) ?:
crypto_skcipher_decrypt(subreq) ?:
post_crypt(req);
if (err == -EINPROGRESS ||
(err == -EBUSY &&
req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG))
return err;
}
exit_crypt(req);
return err;
}
static void decrypt_done(struct crypto_async_request *areq, int err)
{
struct skcipher_request *req = areq->data;
struct skcipher_request *subreq;
struct rctx *rctx;
rctx = skcipher_request_ctx(req);
subreq = &rctx->subreq;
subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
err = do_decrypt(req, err ?: post_crypt(req));
if (rctx->left)
return;
skcipher_request_complete(req, err);
}
static int decrypt(struct skcipher_request *req)
{
return do_decrypt(req, init_crypt(req, decrypt_done));
}
int lrw_crypt(struct blkcipher_desc *desc, struct scatterlist *sdst,
struct scatterlist *ssrc, unsigned int nbytes,
struct lrw_crypt_req *req)
{
const unsigned int bsize = LRW_BLOCK_SIZE;
const unsigned int max_blks = req->tbuflen / bsize;
struct lrw_table_ctx *ctx = req->table_ctx;
struct blkcipher_walk walk;
unsigned int nblocks;
be128 *iv, *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(walk.nbytes / bsize, max_blks);
src = (be128 *)walk.src.virt.addr;
dst = (be128 *)walk.dst.virt.addr;
/* calculate first value of T */
iv = (be128 *)walk.iv;
t_buf[0] = *iv;
/* T <- I*Key2 */
gf128mul_64k_bbe(&t_buf[0], ctx->table);
i = 0;
goto first;
for (;;) {
do {
for (i = 0; i < nblocks; i++) {
/* T <- I*Key2, using the optimization
* discussed in the specification */
be128_xor(&t_buf[i], t,
&ctx->mulinc[get_index128(iv)]);
inc(iv);
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);
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(lrw_crypt);
static int init_tfm(struct crypto_skcipher *tfm)
{
struct skcipher_instance *inst = skcipher_alg_instance(tfm);
struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
struct priv *ctx = crypto_skcipher_ctx(tfm);
struct crypto_skcipher *cipher;
cipher = crypto_spawn_skcipher(spawn);
if (IS_ERR(cipher))
return PTR_ERR(cipher);
ctx->child = cipher;
crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(cipher) +
sizeof(struct rctx));
return 0;
}
static void exit_tfm(struct crypto_skcipher *tfm)
{
struct priv *ctx = crypto_skcipher_ctx(tfm);
lrw_free_table(&ctx->table);
crypto_free_skcipher(ctx->child);
}
static void free(struct skcipher_instance *inst)
{
crypto_drop_skcipher(skcipher_instance_ctx(inst));
kfree(inst);
}
static int create(struct crypto_template *tmpl, struct rtattr **tb)
{
struct crypto_skcipher_spawn *spawn;
struct skcipher_instance *inst;
struct crypto_attr_type *algt;
struct skcipher_alg *alg;
const char *cipher_name;
char ecb_name[CRYPTO_MAX_ALG_NAME];
int err;
algt = crypto_get_attr_type(tb);
if (IS_ERR(algt))
return PTR_ERR(algt);
if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
return -EINVAL;
cipher_name = crypto_attr_alg_name(tb[1]);
if (IS_ERR(cipher_name))
return PTR_ERR(cipher_name);
inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
if (!inst)
return -ENOMEM;
spawn = skcipher_instance_ctx(inst);
crypto_set_skcipher_spawn(spawn, skcipher_crypto_instance(inst));
err = crypto_grab_skcipher(spawn, cipher_name, 0,
crypto_requires_sync(algt->type,
algt->mask));
if (err == -ENOENT) {
err = -ENAMETOOLONG;
if (snprintf(ecb_name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
cipher_name) >= CRYPTO_MAX_ALG_NAME)
goto err_free_inst;
err = crypto_grab_skcipher(spawn, ecb_name, 0,
crypto_requires_sync(algt->type,
algt->mask));
}
if (err)
goto err_free_inst;
alg = crypto_skcipher_spawn_alg(spawn);
err = -EINVAL;
if (alg->base.cra_blocksize != LRW_BLOCK_SIZE)
goto err_drop_spawn;
if (crypto_skcipher_alg_ivsize(alg))
goto err_drop_spawn;
err = crypto_inst_setname(skcipher_crypto_instance(inst), "lrw",
&alg->base);
if (err)
goto err_drop_spawn;
err = -EINVAL;
cipher_name = alg->base.cra_name;
/* Alas we screwed up the naming so we have to mangle the
* cipher name.
*/
if (!strncmp(cipher_name, "ecb(", 4)) {
unsigned len;
len = strlcpy(ecb_name, cipher_name + 4, sizeof(ecb_name));
if (len < 2 || len >= sizeof(ecb_name))
goto err_drop_spawn;
if (ecb_name[len - 1] != ')')
goto err_drop_spawn;
ecb_name[len - 1] = 0;
if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
"lrw(%s)", ecb_name) >= CRYPTO_MAX_ALG_NAME)
return -ENAMETOOLONG;
}
inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
inst->alg.base.cra_priority = alg->base.cra_priority;
inst->alg.base.cra_blocksize = LRW_BLOCK_SIZE;
inst->alg.base.cra_alignmask = alg->base.cra_alignmask |
(__alignof__(u64) - 1);
inst->alg.ivsize = LRW_BLOCK_SIZE;
inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) +
LRW_BLOCK_SIZE;
inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) +
LRW_BLOCK_SIZE;
inst->alg.base.cra_ctxsize = sizeof(struct priv);
inst->alg.init = init_tfm;
inst->alg.exit = exit_tfm;
inst->alg.setkey = setkey;
inst->alg.encrypt = encrypt;
inst->alg.decrypt = decrypt;
inst->free = free;
err = skcipher_register_instance(tmpl, inst);
if (err)
goto err_drop_spawn;
out:
return err;
err_drop_spawn:
crypto_drop_skcipher(spawn);
err_free_inst:
kfree(inst);
goto out;
}
static struct crypto_template crypto_tmpl = {
.name = "lrw",
.create = create,
.module = THIS_MODULE,
};
static int __init crypto_module_init(void)
{
return crypto_register_template(&crypto_tmpl);
}
static void __exit crypto_module_exit(void)
{
crypto_unregister_template(&crypto_tmpl);
}
module_init(crypto_module_init);
module_exit(crypto_module_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("LRW block cipher mode");
MODULE_ALIAS_CRYPTO("lrw");