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/*
* Symmetric key cipher operations.
*
* Generic encrypt/decrypt wrapper for ciphers, handles operations across
* multiple page boundaries by using temporary blocks. In user context,
* the kernel is given a chance to schedule us once per page.
*
* Copyright (c) 2015 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.
*
*/
#include <crypto/internal/skcipher.h>
#include <linux/bug.h>
#include <linux/module.h>
#include "internal.h"
static unsigned int crypto_skcipher_extsize(struct crypto_alg *alg)
{
if (alg->cra_type == &crypto_blkcipher_type)
return sizeof(struct crypto_blkcipher *);
BUG_ON(alg->cra_type != &crypto_ablkcipher_type &&
alg->cra_type != &crypto_givcipher_type);
return sizeof(struct crypto_ablkcipher *);
}
static int skcipher_setkey_blkcipher(struct crypto_skcipher *tfm,
const u8 *key, unsigned int keylen)
{
struct crypto_blkcipher **ctx = crypto_skcipher_ctx(tfm);
struct crypto_blkcipher *blkcipher = *ctx;
int err;
crypto_blkcipher_clear_flags(blkcipher, ~0);
crypto_blkcipher_set_flags(blkcipher, crypto_skcipher_get_flags(tfm) &
CRYPTO_TFM_REQ_MASK);
err = crypto_blkcipher_setkey(blkcipher, key, keylen);
crypto_skcipher_set_flags(tfm, crypto_blkcipher_get_flags(blkcipher) &
CRYPTO_TFM_RES_MASK);
return err;
}
static int skcipher_crypt_blkcipher(struct skcipher_request *req,
int (*crypt)(struct blkcipher_desc *,
struct scatterlist *,
struct scatterlist *,
unsigned int))
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct crypto_blkcipher **ctx = crypto_skcipher_ctx(tfm);
struct blkcipher_desc desc = {
.tfm = *ctx,
.info = req->iv,
.flags = req->base.flags,
};
return crypt(&desc, req->dst, req->src, req->cryptlen);
}
static int skcipher_encrypt_blkcipher(struct skcipher_request *req)
{
struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
return skcipher_crypt_blkcipher(req, alg->encrypt);
}
static int skcipher_decrypt_blkcipher(struct skcipher_request *req)
{
struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
return skcipher_crypt_blkcipher(req, alg->decrypt);
}
static void crypto_exit_skcipher_ops_blkcipher(struct crypto_tfm *tfm)
{
struct crypto_blkcipher **ctx = crypto_tfm_ctx(tfm);
crypto_free_blkcipher(*ctx);
}
static int crypto_init_skcipher_ops_blkcipher(struct crypto_tfm *tfm)
{
struct crypto_alg *calg = tfm->__crt_alg;
struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
struct crypto_blkcipher **ctx = crypto_tfm_ctx(tfm);
struct crypto_blkcipher *blkcipher;
struct crypto_tfm *btfm;
if (!crypto_mod_get(calg))
return -EAGAIN;
btfm = __crypto_alloc_tfm(calg, CRYPTO_ALG_TYPE_BLKCIPHER,
CRYPTO_ALG_TYPE_MASK);
if (IS_ERR(btfm)) {
crypto_mod_put(calg);
return PTR_ERR(btfm);
}
blkcipher = __crypto_blkcipher_cast(btfm);
*ctx = blkcipher;
tfm->exit = crypto_exit_skcipher_ops_blkcipher;
skcipher->setkey = skcipher_setkey_blkcipher;
skcipher->encrypt = skcipher_encrypt_blkcipher;
skcipher->decrypt = skcipher_decrypt_blkcipher;
skcipher->ivsize = crypto_blkcipher_ivsize(blkcipher);
skcipher->keysize = calg->cra_blkcipher.max_keysize;
return 0;
}
static int skcipher_setkey_ablkcipher(struct crypto_skcipher *tfm,
const u8 *key, unsigned int keylen)
{
struct crypto_ablkcipher **ctx = crypto_skcipher_ctx(tfm);
struct crypto_ablkcipher *ablkcipher = *ctx;
int err;
crypto_ablkcipher_clear_flags(ablkcipher, ~0);
crypto_ablkcipher_set_flags(ablkcipher,
crypto_skcipher_get_flags(tfm) &
CRYPTO_TFM_REQ_MASK);
err = crypto_ablkcipher_setkey(ablkcipher, key, keylen);
crypto_skcipher_set_flags(tfm,
crypto_ablkcipher_get_flags(ablkcipher) &
CRYPTO_TFM_RES_MASK);
return err;
}
static int skcipher_crypt_ablkcipher(struct skcipher_request *req,
int (*crypt)(struct ablkcipher_request *))
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct crypto_ablkcipher **ctx = crypto_skcipher_ctx(tfm);
struct ablkcipher_request *subreq = skcipher_request_ctx(req);
ablkcipher_request_set_tfm(subreq, *ctx);
ablkcipher_request_set_callback(subreq, skcipher_request_flags(req),
req->base.complete, req->base.data);
ablkcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen,
req->iv);
return crypt(subreq);
}
static int skcipher_encrypt_ablkcipher(struct skcipher_request *req)
{
struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
return skcipher_crypt_ablkcipher(req, alg->encrypt);
}
static int skcipher_decrypt_ablkcipher(struct skcipher_request *req)
{
struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
return skcipher_crypt_ablkcipher(req, alg->decrypt);
}
static void crypto_exit_skcipher_ops_ablkcipher(struct crypto_tfm *tfm)
{
struct crypto_ablkcipher **ctx = crypto_tfm_ctx(tfm);
crypto_free_ablkcipher(*ctx);
}
static int crypto_init_skcipher_ops_ablkcipher(struct crypto_tfm *tfm)
{
struct crypto_alg *calg = tfm->__crt_alg;
struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
struct crypto_ablkcipher **ctx = crypto_tfm_ctx(tfm);
struct crypto_ablkcipher *ablkcipher;
struct crypto_tfm *abtfm;
if (!crypto_mod_get(calg))
return -EAGAIN;
abtfm = __crypto_alloc_tfm(calg, 0, 0);
if (IS_ERR(abtfm)) {
crypto_mod_put(calg);
return PTR_ERR(abtfm);
}
ablkcipher = __crypto_ablkcipher_cast(abtfm);
*ctx = ablkcipher;
tfm->exit = crypto_exit_skcipher_ops_ablkcipher;
skcipher->setkey = skcipher_setkey_ablkcipher;
skcipher->encrypt = skcipher_encrypt_ablkcipher;
skcipher->decrypt = skcipher_decrypt_ablkcipher;
skcipher->ivsize = crypto_ablkcipher_ivsize(ablkcipher);
skcipher->reqsize = crypto_ablkcipher_reqsize(ablkcipher) +
sizeof(struct ablkcipher_request);
skcipher->keysize = calg->cra_ablkcipher.max_keysize;
return 0;
}
static int crypto_skcipher_init_tfm(struct crypto_tfm *tfm)
{
if (tfm->__crt_alg->cra_type == &crypto_blkcipher_type)
return crypto_init_skcipher_ops_blkcipher(tfm);
BUG_ON(tfm->__crt_alg->cra_type != &crypto_ablkcipher_type &&
tfm->__crt_alg->cra_type != &crypto_givcipher_type);
return crypto_init_skcipher_ops_ablkcipher(tfm);
}
static const struct crypto_type crypto_skcipher_type2 = {
.extsize = crypto_skcipher_extsize,
.init_tfm = crypto_skcipher_init_tfm,
.maskclear = ~CRYPTO_ALG_TYPE_MASK,
.maskset = CRYPTO_ALG_TYPE_BLKCIPHER_MASK,
.type = CRYPTO_ALG_TYPE_BLKCIPHER,
.tfmsize = offsetof(struct crypto_skcipher, base),
};
struct crypto_skcipher *crypto_alloc_skcipher(const char *alg_name,
u32 type, u32 mask)
{
return crypto_alloc_tfm(alg_name, &crypto_skcipher_type2, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_alloc_skcipher);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Symmetric key cipher type");
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