mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 03:10:12 +00:00
![Herbert Xu](/assets/img/avatar_default.png)
The lrw template relies on ecb to work. So we need to declare a Kconfig dependency as well as a module softdep on it. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
431 lines
11 KiB
C
431 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/* 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 implementation is checked against the test vectors in the above
|
|
* document and by a test vector provided by Ken Buchanan at
|
|
* https://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>
|
|
|
|
#define LRW_BLOCK_SIZE 16
|
|
|
|
struct lrw_tfm_ctx {
|
|
struct crypto_skcipher *child;
|
|
|
|
/*
|
|
* optimizes multiplying a random (non incrementing, as at the
|
|
* start of a new sector) value with key2, we could also have
|
|
* used 4k optimization tables or no optimization at all. In the
|
|
* latter case we would have to store key2 here
|
|
*/
|
|
struct gf128mul_64k *table;
|
|
|
|
/*
|
|
* stores:
|
|
* key2*{ 0,0,...0,0,0,0,1 }, key2*{ 0,0,...0,0,0,1,1 },
|
|
* key2*{ 0,0,...0,0,1,1,1 }, key2*{ 0,0,...0,1,1,1,1 }
|
|
* key2*{ 0,0,...1,1,1,1,1 }, etc
|
|
* needed for optimized multiplication of incrementing values
|
|
* with key2
|
|
*/
|
|
be128 mulinc[128];
|
|
};
|
|
|
|
struct lrw_request_ctx {
|
|
be128 t;
|
|
struct skcipher_request subreq;
|
|
};
|
|
|
|
static inline void lrw_setbit128_bbe(void *b, int bit)
|
|
{
|
|
__set_bit(bit ^ (0x80 -
|
|
#ifdef __BIG_ENDIAN
|
|
BITS_PER_LONG
|
|
#else
|
|
BITS_PER_BYTE
|
|
#endif
|
|
), b);
|
|
}
|
|
|
|
static int lrw_setkey(struct crypto_skcipher *parent, const u8 *key,
|
|
unsigned int keylen)
|
|
{
|
|
struct lrw_tfm_ctx *ctx = crypto_skcipher_ctx(parent);
|
|
struct crypto_skcipher *child = ctx->child;
|
|
int err, bsize = LRW_BLOCK_SIZE;
|
|
const u8 *tweak = key + keylen - bsize;
|
|
be128 tmp = { 0 };
|
|
int i;
|
|
|
|
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);
|
|
if (err)
|
|
return err;
|
|
|
|
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++) {
|
|
lrw_setbit128_bbe(&tmp, i);
|
|
ctx->mulinc[i] = tmp;
|
|
gf128mul_64k_bbe(&ctx->mulinc[i], ctx->table);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Returns the number of trailing '1' bits in the words of the counter, which is
|
|
* represented by 4 32-bit words, arranged from least to most significant.
|
|
* At the same time, increments the counter by one.
|
|
*
|
|
* For example:
|
|
*
|
|
* u32 counter[4] = { 0xFFFFFFFF, 0x1, 0x0, 0x0 };
|
|
* int i = lrw_next_index(&counter);
|
|
* // i == 33, counter == { 0x0, 0x2, 0x0, 0x0 }
|
|
*/
|
|
static int lrw_next_index(u32 *counter)
|
|
{
|
|
int i, res = 0;
|
|
|
|
for (i = 0; i < 4; i++) {
|
|
if (counter[i] + 1 != 0)
|
|
return res + ffz(counter[i]++);
|
|
|
|
counter[i] = 0;
|
|
res += 32;
|
|
}
|
|
|
|
/*
|
|
* If we get here, then x == 128 and we are incrementing the counter
|
|
* from all ones to all zeros. This means we must return index 127, i.e.
|
|
* the one corresponding to key2*{ 1,...,1 }.
|
|
*/
|
|
return 127;
|
|
}
|
|
|
|
/*
|
|
* We compute the tweak masks twice (both before and after the ECB encryption or
|
|
* decryption) to avoid having to allocate a temporary buffer and/or make
|
|
* mutliple calls to the 'ecb(..)' instance, which usually would be slower than
|
|
* just doing the lrw_next_index() calls again.
|
|
*/
|
|
static int lrw_xor_tweak(struct skcipher_request *req, bool second_pass)
|
|
{
|
|
const int bs = LRW_BLOCK_SIZE;
|
|
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
|
|
const struct lrw_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
|
|
struct lrw_request_ctx *rctx = skcipher_request_ctx(req);
|
|
be128 t = rctx->t;
|
|
struct skcipher_walk w;
|
|
__be32 *iv;
|
|
u32 counter[4];
|
|
int err;
|
|
|
|
if (second_pass) {
|
|
req = &rctx->subreq;
|
|
/* set to our TFM to enforce correct alignment: */
|
|
skcipher_request_set_tfm(req, tfm);
|
|
}
|
|
|
|
err = skcipher_walk_virt(&w, req, false);
|
|
if (err)
|
|
return err;
|
|
|
|
iv = (__be32 *)w.iv;
|
|
counter[0] = be32_to_cpu(iv[3]);
|
|
counter[1] = be32_to_cpu(iv[2]);
|
|
counter[2] = be32_to_cpu(iv[1]);
|
|
counter[3] = be32_to_cpu(iv[0]);
|
|
|
|
while (w.nbytes) {
|
|
unsigned int avail = w.nbytes;
|
|
be128 *wsrc;
|
|
be128 *wdst;
|
|
|
|
wsrc = w.src.virt.addr;
|
|
wdst = w.dst.virt.addr;
|
|
|
|
do {
|
|
be128_xor(wdst++, &t, wsrc++);
|
|
|
|
/* T <- I*Key2, using the optimization
|
|
* discussed in the specification */
|
|
be128_xor(&t, &t,
|
|
&ctx->mulinc[lrw_next_index(counter)]);
|
|
} while ((avail -= bs) >= bs);
|
|
|
|
if (second_pass && w.nbytes == w.total) {
|
|
iv[0] = cpu_to_be32(counter[3]);
|
|
iv[1] = cpu_to_be32(counter[2]);
|
|
iv[2] = cpu_to_be32(counter[1]);
|
|
iv[3] = cpu_to_be32(counter[0]);
|
|
}
|
|
|
|
err = skcipher_walk_done(&w, avail);
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static int lrw_xor_tweak_pre(struct skcipher_request *req)
|
|
{
|
|
return lrw_xor_tweak(req, false);
|
|
}
|
|
|
|
static int lrw_xor_tweak_post(struct skcipher_request *req)
|
|
{
|
|
return lrw_xor_tweak(req, true);
|
|
}
|
|
|
|
static void lrw_crypt_done(struct crypto_async_request *areq, int err)
|
|
{
|
|
struct skcipher_request *req = areq->data;
|
|
|
|
if (!err) {
|
|
struct lrw_request_ctx *rctx = skcipher_request_ctx(req);
|
|
|
|
rctx->subreq.base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
|
|
err = lrw_xor_tweak_post(req);
|
|
}
|
|
|
|
skcipher_request_complete(req, err);
|
|
}
|
|
|
|
static void lrw_init_crypt(struct skcipher_request *req)
|
|
{
|
|
const struct lrw_tfm_ctx *ctx =
|
|
crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
|
|
struct lrw_request_ctx *rctx = skcipher_request_ctx(req);
|
|
struct skcipher_request *subreq = &rctx->subreq;
|
|
|
|
skcipher_request_set_tfm(subreq, ctx->child);
|
|
skcipher_request_set_callback(subreq, req->base.flags, lrw_crypt_done,
|
|
req);
|
|
/* pass req->iv as IV (will be used by xor_tweak, ECB will ignore it) */
|
|
skcipher_request_set_crypt(subreq, req->dst, req->dst,
|
|
req->cryptlen, req->iv);
|
|
|
|
/* calculate first value of T */
|
|
memcpy(&rctx->t, req->iv, sizeof(rctx->t));
|
|
|
|
/* T <- I*Key2 */
|
|
gf128mul_64k_bbe(&rctx->t, ctx->table);
|
|
}
|
|
|
|
static int lrw_encrypt(struct skcipher_request *req)
|
|
{
|
|
struct lrw_request_ctx *rctx = skcipher_request_ctx(req);
|
|
struct skcipher_request *subreq = &rctx->subreq;
|
|
|
|
lrw_init_crypt(req);
|
|
return lrw_xor_tweak_pre(req) ?:
|
|
crypto_skcipher_encrypt(subreq) ?:
|
|
lrw_xor_tweak_post(req);
|
|
}
|
|
|
|
static int lrw_decrypt(struct skcipher_request *req)
|
|
{
|
|
struct lrw_request_ctx *rctx = skcipher_request_ctx(req);
|
|
struct skcipher_request *subreq = &rctx->subreq;
|
|
|
|
lrw_init_crypt(req);
|
|
return lrw_xor_tweak_pre(req) ?:
|
|
crypto_skcipher_decrypt(subreq) ?:
|
|
lrw_xor_tweak_post(req);
|
|
}
|
|
|
|
static int lrw_init_tfm(struct crypto_skcipher *tfm)
|
|
{
|
|
struct skcipher_instance *inst = skcipher_alg_instance(tfm);
|
|
struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
|
|
struct lrw_tfm_ctx *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 lrw_request_ctx));
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void lrw_exit_tfm(struct crypto_skcipher *tfm)
|
|
{
|
|
struct lrw_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
|
|
|
|
if (ctx->table)
|
|
gf128mul_free_64k(ctx->table);
|
|
crypto_free_skcipher(ctx->child);
|
|
}
|
|
|
|
static void lrw_free_instance(struct skcipher_instance *inst)
|
|
{
|
|
crypto_drop_skcipher(skcipher_instance_ctx(inst));
|
|
kfree(inst);
|
|
}
|
|
|
|
static int lrw_create(struct crypto_template *tmpl, struct rtattr **tb)
|
|
{
|
|
struct crypto_skcipher_spawn *spawn;
|
|
struct skcipher_instance *inst;
|
|
struct skcipher_alg *alg;
|
|
const char *cipher_name;
|
|
char ecb_name[CRYPTO_MAX_ALG_NAME];
|
|
u32 mask;
|
|
int err;
|
|
|
|
err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER, &mask);
|
|
if (err)
|
|
return err;
|
|
|
|
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);
|
|
|
|
err = crypto_grab_skcipher(spawn, skcipher_crypto_instance(inst),
|
|
cipher_name, 0, 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,
|
|
skcipher_crypto_instance(inst),
|
|
ecb_name, 0, 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_free_inst;
|
|
|
|
if (crypto_skcipher_alg_ivsize(alg))
|
|
goto err_free_inst;
|
|
|
|
err = crypto_inst_setname(skcipher_crypto_instance(inst), "lrw",
|
|
&alg->base);
|
|
if (err)
|
|
goto err_free_inst;
|
|
|
|
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_free_inst;
|
|
|
|
if (ecb_name[len - 1] != ')')
|
|
goto err_free_inst;
|
|
|
|
ecb_name[len - 1] = 0;
|
|
|
|
if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
|
|
"lrw(%s)", ecb_name) >= CRYPTO_MAX_ALG_NAME) {
|
|
err = -ENAMETOOLONG;
|
|
goto err_free_inst;
|
|
}
|
|
} else
|
|
goto err_free_inst;
|
|
|
|
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__(be128) - 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 lrw_tfm_ctx);
|
|
|
|
inst->alg.init = lrw_init_tfm;
|
|
inst->alg.exit = lrw_exit_tfm;
|
|
|
|
inst->alg.setkey = lrw_setkey;
|
|
inst->alg.encrypt = lrw_encrypt;
|
|
inst->alg.decrypt = lrw_decrypt;
|
|
|
|
inst->free = lrw_free_instance;
|
|
|
|
err = skcipher_register_instance(tmpl, inst);
|
|
if (err) {
|
|
err_free_inst:
|
|
lrw_free_instance(inst);
|
|
}
|
|
return err;
|
|
}
|
|
|
|
static struct crypto_template lrw_tmpl = {
|
|
.name = "lrw",
|
|
.create = lrw_create,
|
|
.module = THIS_MODULE,
|
|
};
|
|
|
|
static int __init lrw_module_init(void)
|
|
{
|
|
return crypto_register_template(&lrw_tmpl);
|
|
}
|
|
|
|
static void __exit lrw_module_exit(void)
|
|
{
|
|
crypto_unregister_template(&lrw_tmpl);
|
|
}
|
|
|
|
subsys_initcall(lrw_module_init);
|
|
module_exit(lrw_module_exit);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_DESCRIPTION("LRW block cipher mode");
|
|
MODULE_ALIAS_CRYPTO("lrw");
|
|
MODULE_SOFTDEP("pre: ecb");
|