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linux/crypto/ecb.c
Herbert Xu 0ae4dcc1eb crypto: skcipher - Add internal state support 
Unlike chaining modes such as CBC, stream ciphers other than CTR
usually hold an internal state that must be preserved if the
operation is to be done piecemeal.  This has not been represented
in the API, resulting in the inability to split up stream cipher
operations.

This patch adds the basic representation of an internal state to
skcipher and lskcipher.  In the interest of backwards compatibility,
the default has been set such that existing users are assumed to
be operating in one go as opposed to piecemeal.

With the new API, each lskcipher/skcipher algorithm has a new
attribute called statesize.  For skcipher, this is the size of
the buffer that can be exported or imported similar to ahash.
For lskcipher, instead of providing a buffer of ivsize, the user
now has to provide a buffer of ivsize + statesize.

Each skcipher operation is assumed to be final as they are now,
but this may be overridden with a request flag.  When the override
occurs, the user may then export the partial state and reimport
it later.

For lskcipher operations this is reversed.  All operations are
not final and the state will be exported unless the FINAL bit is
set.  However, the CONT bit still has to be set for the state
to be used.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-12-08 11:59:46 +08:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* ECB: Electronic CodeBook mode
*
* Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
*/
#include <crypto/internal/cipher.h>
#include <crypto/internal/skcipher.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
static int crypto_ecb_crypt(struct crypto_cipher *cipher, const u8 *src,
u8 *dst, unsigned nbytes, bool final,
void (*fn)(struct crypto_tfm *, u8 *, const u8 *))
{
const unsigned int bsize = crypto_cipher_blocksize(cipher);
while (nbytes >= bsize) {
fn(crypto_cipher_tfm(cipher), dst, src);
src += bsize;
dst += bsize;
nbytes -= bsize;
}
return nbytes && final ? -EINVAL : nbytes;
}
static int crypto_ecb_encrypt2(struct crypto_lskcipher *tfm, const u8 *src,
u8 *dst, unsigned len, u8 *iv, u32 flags)
{
struct crypto_cipher **ctx = crypto_lskcipher_ctx(tfm);
struct crypto_cipher *cipher = *ctx;
return crypto_ecb_crypt(cipher, src, dst, len,
flags & CRYPTO_LSKCIPHER_FLAG_FINAL,
crypto_cipher_alg(cipher)->cia_encrypt);
}
static int crypto_ecb_decrypt2(struct crypto_lskcipher *tfm, const u8 *src,
u8 *dst, unsigned len, u8 *iv, u32 flags)
{
struct crypto_cipher **ctx = crypto_lskcipher_ctx(tfm);
struct crypto_cipher *cipher = *ctx;
return crypto_ecb_crypt(cipher, src, dst, len,
flags & CRYPTO_LSKCIPHER_FLAG_FINAL,
crypto_cipher_alg(cipher)->cia_decrypt);
}
static int lskcipher_setkey_simple2(struct crypto_lskcipher *tfm,
const u8 *key, unsigned int keylen)
{
struct crypto_cipher **ctx = crypto_lskcipher_ctx(tfm);
struct crypto_cipher *cipher = *ctx;
crypto_cipher_clear_flags(cipher, CRYPTO_TFM_REQ_MASK);
crypto_cipher_set_flags(cipher, crypto_lskcipher_get_flags(tfm) &
CRYPTO_TFM_REQ_MASK);
return crypto_cipher_setkey(cipher, key, keylen);
}
static int lskcipher_init_tfm_simple2(struct crypto_lskcipher *tfm)
{
struct lskcipher_instance *inst = lskcipher_alg_instance(tfm);
struct crypto_cipher **ctx = crypto_lskcipher_ctx(tfm);
struct crypto_cipher_spawn *spawn;
struct crypto_cipher *cipher;
spawn = lskcipher_instance_ctx(inst);
cipher = crypto_spawn_cipher(spawn);
if (IS_ERR(cipher))
return PTR_ERR(cipher);
*ctx = cipher;
return 0;
}
static void lskcipher_exit_tfm_simple2(struct crypto_lskcipher *tfm)
{
struct crypto_cipher **ctx = crypto_lskcipher_ctx(tfm);
crypto_free_cipher(*ctx);
}
static void lskcipher_free_instance_simple2(struct lskcipher_instance *inst)
{
crypto_drop_cipher(lskcipher_instance_ctx(inst));
kfree(inst);
}
static struct lskcipher_instance *lskcipher_alloc_instance_simple2(
struct crypto_template *tmpl, struct rtattr **tb)
{
struct crypto_cipher_spawn *spawn;
struct lskcipher_instance *inst;
struct crypto_alg *cipher_alg;
u32 mask;
int err;
err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_LSKCIPHER, &mask);
if (err)
return ERR_PTR(err);
inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
if (!inst)
return ERR_PTR(-ENOMEM);
spawn = lskcipher_instance_ctx(inst);
err = crypto_grab_cipher(spawn, lskcipher_crypto_instance(inst),
crypto_attr_alg_name(tb[1]), 0, mask);
if (err)
goto err_free_inst;
cipher_alg = crypto_spawn_cipher_alg(spawn);
err = crypto_inst_setname(lskcipher_crypto_instance(inst), tmpl->name,
cipher_alg);
if (err)
goto err_free_inst;
inst->free = lskcipher_free_instance_simple2;
/* Default algorithm properties, can be overridden */
inst->alg.co.base.cra_blocksize = cipher_alg->cra_blocksize;
inst->alg.co.base.cra_alignmask = cipher_alg->cra_alignmask;
inst->alg.co.base.cra_priority = cipher_alg->cra_priority;
inst->alg.co.min_keysize = cipher_alg->cra_cipher.cia_min_keysize;
inst->alg.co.max_keysize = cipher_alg->cra_cipher.cia_max_keysize;
inst->alg.co.ivsize = cipher_alg->cra_blocksize;
/* Use struct crypto_cipher * by default, can be overridden */
inst->alg.co.base.cra_ctxsize = sizeof(struct crypto_cipher *);
inst->alg.setkey = lskcipher_setkey_simple2;
inst->alg.init = lskcipher_init_tfm_simple2;
inst->alg.exit = lskcipher_exit_tfm_simple2;
return inst;
err_free_inst:
lskcipher_free_instance_simple2(inst);
return ERR_PTR(err);
}
static int crypto_ecb_create2(struct crypto_template *tmpl, struct rtattr **tb)
{
struct lskcipher_instance *inst;
int err;
inst = lskcipher_alloc_instance_simple2(tmpl, tb);
if (IS_ERR(inst))
return PTR_ERR(inst);
/* ECB mode doesn't take an IV */
inst->alg.co.ivsize = 0;
inst->alg.encrypt = crypto_ecb_encrypt2;
inst->alg.decrypt = crypto_ecb_decrypt2;
err = lskcipher_register_instance(tmpl, inst);
if (err)
inst->free(inst);
return err;
}
static int crypto_ecb_create(struct crypto_template *tmpl, struct rtattr **tb)
{
struct crypto_lskcipher_spawn *spawn;
struct lskcipher_alg *cipher_alg;
struct lskcipher_instance *inst;
int err;
inst = lskcipher_alloc_instance_simple(tmpl, tb);
if (IS_ERR(inst)) {
err = crypto_ecb_create2(tmpl, tb);
return err;
}
spawn = lskcipher_instance_ctx(inst);
cipher_alg = crypto_lskcipher_spawn_alg(spawn);
/* ECB mode doesn't take an IV */
inst->alg.co.ivsize = 0;
if (cipher_alg->co.ivsize)
return -EINVAL;
inst->alg.co.base.cra_ctxsize = cipher_alg->co.base.cra_ctxsize;
inst->alg.setkey = cipher_alg->setkey;
inst->alg.encrypt = cipher_alg->encrypt;
inst->alg.decrypt = cipher_alg->decrypt;
inst->alg.init = cipher_alg->init;
inst->alg.exit = cipher_alg->exit;
err = lskcipher_register_instance(tmpl, inst);
if (err)
inst->free(inst);
return err;
}
static struct crypto_template crypto_ecb_tmpl = {
.name = "ecb",
.create = crypto_ecb_create,
.module = THIS_MODULE,
};
static int __init crypto_ecb_module_init(void)
{
return crypto_register_template(&crypto_ecb_tmpl);
}
static void __exit crypto_ecb_module_exit(void)
{
crypto_unregister_template(&crypto_ecb_tmpl);
}
subsys_initcall(crypto_ecb_module_init);
module_exit(crypto_ecb_module_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("ECB block cipher mode of operation");
MODULE_ALIAS_CRYPTO("ecb");
MODULE_IMPORT_NS(CRYPTO_INTERNAL);
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