mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 17:30:02 +00:00
![Eric Biggers](/assets/img/avatar_default.png)
Initializing a crypto_skcipher_spawn currently requires:
1. Set spawn->base.inst to point to the instance.
2. Call crypto_grab_skcipher().
But there's no reason for these steps to be separate, and in fact this
unneeded complication has caused at least one bug, the one fixed by
commit 6db4341017
("crypto: adiantum - initialize crypto_spawn::inst")
So just make crypto_grab_skcipher() take the instance as an argument.
To keep the function calls from getting too unwieldy due to this extra
argument, also introduce a 'mask' variable into the affected places
which weren't already using one.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
474 lines
12 KiB
C
474 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/* XTS: as defined in IEEE1619/D16
|
|
* http://grouper.ieee.org/groups/1619/email/pdf00086.pdf
|
|
*
|
|
* Copyright (c) 2007 Rik Snel <rsnel@cube.dyndns.org>
|
|
*
|
|
* Based on ecb.c
|
|
* Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
|
|
*/
|
|
#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/xts.h>
|
|
#include <crypto/b128ops.h>
|
|
#include <crypto/gf128mul.h>
|
|
|
|
struct priv {
|
|
struct crypto_skcipher *child;
|
|
struct crypto_cipher *tweak;
|
|
};
|
|
|
|
struct xts_instance_ctx {
|
|
struct crypto_skcipher_spawn spawn;
|
|
char name[CRYPTO_MAX_ALG_NAME];
|
|
};
|
|
|
|
struct rctx {
|
|
le128 t;
|
|
struct scatterlist *tail;
|
|
struct scatterlist sg[2];
|
|
struct skcipher_request subreq;
|
|
};
|
|
|
|
static int setkey(struct crypto_skcipher *parent, const u8 *key,
|
|
unsigned int keylen)
|
|
{
|
|
struct priv *ctx = crypto_skcipher_ctx(parent);
|
|
struct crypto_skcipher *child;
|
|
struct crypto_cipher *tweak;
|
|
int err;
|
|
|
|
err = xts_verify_key(parent, key, keylen);
|
|
if (err)
|
|
return err;
|
|
|
|
keylen /= 2;
|
|
|
|
/* we need two cipher instances: one to compute the initial 'tweak'
|
|
* by encrypting the IV (usually the 'plain' iv) and the other
|
|
* one to encrypt and decrypt the data */
|
|
|
|
/* tweak cipher, uses Key2 i.e. the second half of *key */
|
|
tweak = ctx->tweak;
|
|
crypto_cipher_clear_flags(tweak, CRYPTO_TFM_REQ_MASK);
|
|
crypto_cipher_set_flags(tweak, crypto_skcipher_get_flags(parent) &
|
|
CRYPTO_TFM_REQ_MASK);
|
|
err = crypto_cipher_setkey(tweak, key + keylen, keylen);
|
|
if (err)
|
|
return err;
|
|
|
|
/* data cipher, uses Key1 i.e. the first half of *key */
|
|
child = ctx->child;
|
|
crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
|
|
crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
|
|
CRYPTO_TFM_REQ_MASK);
|
|
return crypto_skcipher_setkey(child, key, keylen);
|
|
}
|
|
|
|
/*
|
|
* 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 gf128mul_x_ble() calls again.
|
|
*/
|
|
static int xor_tweak(struct skcipher_request *req, bool second_pass, bool enc)
|
|
{
|
|
struct rctx *rctx = skcipher_request_ctx(req);
|
|
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
|
|
const bool cts = (req->cryptlen % XTS_BLOCK_SIZE);
|
|
const int bs = XTS_BLOCK_SIZE;
|
|
struct skcipher_walk w;
|
|
le128 t = rctx->t;
|
|
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);
|
|
|
|
while (w.nbytes) {
|
|
unsigned int avail = w.nbytes;
|
|
le128 *wsrc;
|
|
le128 *wdst;
|
|
|
|
wsrc = w.src.virt.addr;
|
|
wdst = w.dst.virt.addr;
|
|
|
|
do {
|
|
if (unlikely(cts) &&
|
|
w.total - w.nbytes + avail < 2 * XTS_BLOCK_SIZE) {
|
|
if (!enc) {
|
|
if (second_pass)
|
|
rctx->t = t;
|
|
gf128mul_x_ble(&t, &t);
|
|
}
|
|
le128_xor(wdst, &t, wsrc);
|
|
if (enc && second_pass)
|
|
gf128mul_x_ble(&rctx->t, &t);
|
|
skcipher_walk_done(&w, avail - bs);
|
|
return 0;
|
|
}
|
|
|
|
le128_xor(wdst++, &t, wsrc++);
|
|
gf128mul_x_ble(&t, &t);
|
|
} while ((avail -= bs) >= bs);
|
|
|
|
err = skcipher_walk_done(&w, avail);
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static int xor_tweak_pre(struct skcipher_request *req, bool enc)
|
|
{
|
|
return xor_tweak(req, false, enc);
|
|
}
|
|
|
|
static int xor_tweak_post(struct skcipher_request *req, bool enc)
|
|
{
|
|
return xor_tweak(req, true, enc);
|
|
}
|
|
|
|
static void cts_done(struct crypto_async_request *areq, int err)
|
|
{
|
|
struct skcipher_request *req = areq->data;
|
|
le128 b;
|
|
|
|
if (!err) {
|
|
struct rctx *rctx = skcipher_request_ctx(req);
|
|
|
|
scatterwalk_map_and_copy(&b, rctx->tail, 0, XTS_BLOCK_SIZE, 0);
|
|
le128_xor(&b, &rctx->t, &b);
|
|
scatterwalk_map_and_copy(&b, rctx->tail, 0, XTS_BLOCK_SIZE, 1);
|
|
}
|
|
|
|
skcipher_request_complete(req, err);
|
|
}
|
|
|
|
static int cts_final(struct skcipher_request *req,
|
|
int (*crypt)(struct skcipher_request *req))
|
|
{
|
|
struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
|
|
int offset = req->cryptlen & ~(XTS_BLOCK_SIZE - 1);
|
|
struct rctx *rctx = skcipher_request_ctx(req);
|
|
struct skcipher_request *subreq = &rctx->subreq;
|
|
int tail = req->cryptlen % XTS_BLOCK_SIZE;
|
|
le128 b[2];
|
|
int err;
|
|
|
|
rctx->tail = scatterwalk_ffwd(rctx->sg, req->dst,
|
|
offset - XTS_BLOCK_SIZE);
|
|
|
|
scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE, 0);
|
|
memcpy(b + 1, b, tail);
|
|
scatterwalk_map_and_copy(b, req->src, offset, tail, 0);
|
|
|
|
le128_xor(b, &rctx->t, b);
|
|
|
|
scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE + tail, 1);
|
|
|
|
skcipher_request_set_tfm(subreq, ctx->child);
|
|
skcipher_request_set_callback(subreq, req->base.flags, cts_done, req);
|
|
skcipher_request_set_crypt(subreq, rctx->tail, rctx->tail,
|
|
XTS_BLOCK_SIZE, NULL);
|
|
|
|
err = crypt(subreq);
|
|
if (err)
|
|
return err;
|
|
|
|
scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE, 0);
|
|
le128_xor(b, &rctx->t, b);
|
|
scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE, 1);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void encrypt_done(struct crypto_async_request *areq, int err)
|
|
{
|
|
struct skcipher_request *req = areq->data;
|
|
|
|
if (!err) {
|
|
struct rctx *rctx = skcipher_request_ctx(req);
|
|
|
|
rctx->subreq.base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
|
|
err = xor_tweak_post(req, true);
|
|
|
|
if (!err && unlikely(req->cryptlen % XTS_BLOCK_SIZE)) {
|
|
err = cts_final(req, crypto_skcipher_encrypt);
|
|
if (err == -EINPROGRESS)
|
|
return;
|
|
}
|
|
}
|
|
|
|
skcipher_request_complete(req, err);
|
|
}
|
|
|
|
static void decrypt_done(struct crypto_async_request *areq, int err)
|
|
{
|
|
struct skcipher_request *req = areq->data;
|
|
|
|
if (!err) {
|
|
struct rctx *rctx = skcipher_request_ctx(req);
|
|
|
|
rctx->subreq.base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
|
|
err = xor_tweak_post(req, false);
|
|
|
|
if (!err && unlikely(req->cryptlen % XTS_BLOCK_SIZE)) {
|
|
err = cts_final(req, crypto_skcipher_decrypt);
|
|
if (err == -EINPROGRESS)
|
|
return;
|
|
}
|
|
}
|
|
|
|
skcipher_request_complete(req, err);
|
|
}
|
|
|
|
static int init_crypt(struct skcipher_request *req, crypto_completion_t compl)
|
|
{
|
|
struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
|
|
struct rctx *rctx = skcipher_request_ctx(req);
|
|
struct skcipher_request *subreq = &rctx->subreq;
|
|
|
|
if (req->cryptlen < XTS_BLOCK_SIZE)
|
|
return -EINVAL;
|
|
|
|
skcipher_request_set_tfm(subreq, ctx->child);
|
|
skcipher_request_set_callback(subreq, req->base.flags, compl, req);
|
|
skcipher_request_set_crypt(subreq, req->dst, req->dst,
|
|
req->cryptlen & ~(XTS_BLOCK_SIZE - 1), NULL);
|
|
|
|
/* calculate first value of T */
|
|
crypto_cipher_encrypt_one(ctx->tweak, (u8 *)&rctx->t, req->iv);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int encrypt(struct skcipher_request *req)
|
|
{
|
|
struct rctx *rctx = skcipher_request_ctx(req);
|
|
struct skcipher_request *subreq = &rctx->subreq;
|
|
int err;
|
|
|
|
err = init_crypt(req, encrypt_done) ?:
|
|
xor_tweak_pre(req, true) ?:
|
|
crypto_skcipher_encrypt(subreq) ?:
|
|
xor_tweak_post(req, true);
|
|
|
|
if (err || likely((req->cryptlen % XTS_BLOCK_SIZE) == 0))
|
|
return err;
|
|
|
|
return cts_final(req, crypto_skcipher_encrypt);
|
|
}
|
|
|
|
static int decrypt(struct skcipher_request *req)
|
|
{
|
|
struct rctx *rctx = skcipher_request_ctx(req);
|
|
struct skcipher_request *subreq = &rctx->subreq;
|
|
int err;
|
|
|
|
err = init_crypt(req, decrypt_done) ?:
|
|
xor_tweak_pre(req, false) ?:
|
|
crypto_skcipher_decrypt(subreq) ?:
|
|
xor_tweak_post(req, false);
|
|
|
|
if (err || likely((req->cryptlen % XTS_BLOCK_SIZE) == 0))
|
|
return err;
|
|
|
|
return cts_final(req, crypto_skcipher_decrypt);
|
|
}
|
|
|
|
static int init_tfm(struct crypto_skcipher *tfm)
|
|
{
|
|
struct skcipher_instance *inst = skcipher_alg_instance(tfm);
|
|
struct xts_instance_ctx *ictx = skcipher_instance_ctx(inst);
|
|
struct priv *ctx = crypto_skcipher_ctx(tfm);
|
|
struct crypto_skcipher *child;
|
|
struct crypto_cipher *tweak;
|
|
|
|
child = crypto_spawn_skcipher(&ictx->spawn);
|
|
if (IS_ERR(child))
|
|
return PTR_ERR(child);
|
|
|
|
ctx->child = child;
|
|
|
|
tweak = crypto_alloc_cipher(ictx->name, 0, 0);
|
|
if (IS_ERR(tweak)) {
|
|
crypto_free_skcipher(ctx->child);
|
|
return PTR_ERR(tweak);
|
|
}
|
|
|
|
ctx->tweak = tweak;
|
|
|
|
crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(child) +
|
|
sizeof(struct rctx));
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void exit_tfm(struct crypto_skcipher *tfm)
|
|
{
|
|
struct priv *ctx = crypto_skcipher_ctx(tfm);
|
|
|
|
crypto_free_skcipher(ctx->child);
|
|
crypto_free_cipher(ctx->tweak);
|
|
}
|
|
|
|
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 skcipher_instance *inst;
|
|
struct crypto_attr_type *algt;
|
|
struct xts_instance_ctx *ctx;
|
|
struct skcipher_alg *alg;
|
|
const char *cipher_name;
|
|
u32 mask;
|
|
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(*ctx), GFP_KERNEL);
|
|
if (!inst)
|
|
return -ENOMEM;
|
|
|
|
ctx = skcipher_instance_ctx(inst);
|
|
|
|
mask = crypto_requires_off(algt->type, algt->mask,
|
|
CRYPTO_ALG_NEED_FALLBACK |
|
|
CRYPTO_ALG_ASYNC);
|
|
|
|
err = crypto_grab_skcipher(&ctx->spawn, skcipher_crypto_instance(inst),
|
|
cipher_name, 0, mask);
|
|
if (err == -ENOENT) {
|
|
err = -ENAMETOOLONG;
|
|
if (snprintf(ctx->name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
|
|
cipher_name) >= CRYPTO_MAX_ALG_NAME)
|
|
goto err_free_inst;
|
|
|
|
err = crypto_grab_skcipher(&ctx->spawn,
|
|
skcipher_crypto_instance(inst),
|
|
ctx->name, 0, mask);
|
|
}
|
|
|
|
if (err)
|
|
goto err_free_inst;
|
|
|
|
alg = crypto_skcipher_spawn_alg(&ctx->spawn);
|
|
|
|
err = -EINVAL;
|
|
if (alg->base.cra_blocksize != XTS_BLOCK_SIZE)
|
|
goto err_drop_spawn;
|
|
|
|
if (crypto_skcipher_alg_ivsize(alg))
|
|
goto err_drop_spawn;
|
|
|
|
err = crypto_inst_setname(skcipher_crypto_instance(inst), "xts",
|
|
&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(ctx->name, cipher_name + 4, sizeof(ctx->name));
|
|
if (len < 2 || len >= sizeof(ctx->name))
|
|
goto err_drop_spawn;
|
|
|
|
if (ctx->name[len - 1] != ')')
|
|
goto err_drop_spawn;
|
|
|
|
ctx->name[len - 1] = 0;
|
|
|
|
if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
|
|
"xts(%s)", ctx->name) >= CRYPTO_MAX_ALG_NAME) {
|
|
err = -ENAMETOOLONG;
|
|
goto err_drop_spawn;
|
|
}
|
|
} else
|
|
goto err_drop_spawn;
|
|
|
|
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 = XTS_BLOCK_SIZE;
|
|
inst->alg.base.cra_alignmask = alg->base.cra_alignmask |
|
|
(__alignof__(u64) - 1);
|
|
|
|
inst->alg.ivsize = XTS_BLOCK_SIZE;
|
|
inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) * 2;
|
|
inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) * 2;
|
|
|
|
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(&ctx->spawn);
|
|
err_free_inst:
|
|
kfree(inst);
|
|
goto out;
|
|
}
|
|
|
|
static struct crypto_template crypto_tmpl = {
|
|
.name = "xts",
|
|
.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);
|
|
}
|
|
|
|
subsys_initcall(crypto_module_init);
|
|
module_exit(crypto_module_exit);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_DESCRIPTION("XTS block cipher mode");
|
|
MODULE_ALIAS_CRYPTO("xts");
|