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linux/crypto/pcbc.c
Herbert Xu ebc610e5bc [CRYPTO] templates: Pass type/mask when creating instances 
This patch passes the type/mask along when constructing instances of
templates.  This is in preparation for templates that may support
multiple types of instances depending on what is requested.  For example,
the planned software async crypto driver will use this construct.

For the moment this allows us to check whether the instance constructed
is of the correct type and avoid returning success if the type does not
match.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2007-05-02 14:38:31 +10:00

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/*
* PCBC: Propagating Cipher Block Chaining mode
*
* Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* Derived from cbc.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.
*
*/
#include <crypto/algapi.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>
struct crypto_pcbc_ctx {
struct crypto_cipher *child;
void (*xor)(u8 *dst, const u8 *src, unsigned int bs);
};
static int crypto_pcbc_setkey(struct crypto_tfm *parent, const u8 *key,
unsigned int keylen)
{
struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(parent);
struct crypto_cipher *child = ctx->child;
int err;
crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
CRYPTO_TFM_REQ_MASK);
err = crypto_cipher_setkey(child, key, keylen);
crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
CRYPTO_TFM_RES_MASK);
return err;
}
static int crypto_pcbc_encrypt_segment(struct blkcipher_desc *desc,
struct blkcipher_walk *walk,
struct crypto_cipher *tfm,
void (*xor)(u8 *, const u8 *,
unsigned int))
{
void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
crypto_cipher_alg(tfm)->cia_encrypt;
int bsize = crypto_cipher_blocksize(tfm);
unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr;
u8 *dst = walk->dst.virt.addr;
u8 *iv = walk->iv;
do {
xor(iv, src, bsize);
fn(crypto_cipher_tfm(tfm), dst, iv);
memcpy(iv, dst, bsize);
xor(iv, src, bsize);
src += bsize;
dst += bsize;
} while ((nbytes -= bsize) >= bsize);
return nbytes;
}
static int crypto_pcbc_encrypt_inplace(struct blkcipher_desc *desc,
struct blkcipher_walk *walk,
struct crypto_cipher *tfm,
void (*xor)(u8 *, const u8 *,
unsigned int))
{
void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
crypto_cipher_alg(tfm)->cia_encrypt;
int bsize = crypto_cipher_blocksize(tfm);
unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr;
u8 *iv = walk->iv;
u8 tmpbuf[bsize];
do {
memcpy(tmpbuf, src, bsize);
xor(iv, tmpbuf, bsize);
fn(crypto_cipher_tfm(tfm), src, iv);
memcpy(iv, src, bsize);
xor(iv, tmpbuf, bsize);
src += bsize;
} while ((nbytes -= bsize) >= bsize);
memcpy(walk->iv, iv, bsize);
return nbytes;
}
static int crypto_pcbc_encrypt(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
struct blkcipher_walk walk;
struct crypto_blkcipher *tfm = desc->tfm;
struct crypto_pcbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
struct crypto_cipher *child = ctx->child;
void (*xor)(u8 *, const u8 *, unsigned int bs) = ctx->xor;
int err;
blkcipher_walk_init(&walk, dst, src, nbytes);
err = blkcipher_walk_virt(desc, &walk);
while ((nbytes = walk.nbytes)) {
if (walk.src.virt.addr == walk.dst.virt.addr)
nbytes = crypto_pcbc_encrypt_inplace(desc, &walk, child,
xor);
else
nbytes = crypto_pcbc_encrypt_segment(desc, &walk, child,
xor);
err = blkcipher_walk_done(desc, &walk, nbytes);
}
return err;
}
static int crypto_pcbc_decrypt_segment(struct blkcipher_desc *desc,
struct blkcipher_walk *walk,
struct crypto_cipher *tfm,
void (*xor)(u8 *, const u8 *,
unsigned int))
{
void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
crypto_cipher_alg(tfm)->cia_decrypt;
int bsize = crypto_cipher_blocksize(tfm);
unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr;
u8 *dst = walk->dst.virt.addr;
u8 *iv = walk->iv;
do {
fn(crypto_cipher_tfm(tfm), dst, src);
xor(dst, iv, bsize);
memcpy(iv, src, bsize);
xor(iv, dst, bsize);
src += bsize;
dst += bsize;
} while ((nbytes -= bsize) >= bsize);
memcpy(walk->iv, iv, bsize);
return nbytes;
}
static int crypto_pcbc_decrypt_inplace(struct blkcipher_desc *desc,
struct blkcipher_walk *walk,
struct crypto_cipher *tfm,
void (*xor)(u8 *, const u8 *,
unsigned int))
{
void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
crypto_cipher_alg(tfm)->cia_decrypt;
int bsize = crypto_cipher_blocksize(tfm);
unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr;
u8 *iv = walk->iv;
u8 tmpbuf[bsize];
do {
memcpy(tmpbuf, src, bsize);
fn(crypto_cipher_tfm(tfm), src, src);
xor(src, iv, bsize);
memcpy(iv, tmpbuf, bsize);
xor(iv, src, bsize);
src += bsize;
} while ((nbytes -= bsize) >= bsize);
memcpy(walk->iv, iv, bsize);
return nbytes;
}
static int crypto_pcbc_decrypt(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
struct blkcipher_walk walk;
struct crypto_blkcipher *tfm = desc->tfm;
struct crypto_pcbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
struct crypto_cipher *child = ctx->child;
void (*xor)(u8 *, const u8 *, unsigned int bs) = ctx->xor;
int err;
blkcipher_walk_init(&walk, dst, src, nbytes);
err = blkcipher_walk_virt(desc, &walk);
while ((nbytes = walk.nbytes)) {
if (walk.src.virt.addr == walk.dst.virt.addr)
nbytes = crypto_pcbc_decrypt_inplace(desc, &walk, child,
xor);
else
nbytes = crypto_pcbc_decrypt_segment(desc, &walk, child,
xor);
err = blkcipher_walk_done(desc, &walk, nbytes);
}
return err;
}
static void xor_byte(u8 *a, const u8 *b, unsigned int bs)
{
do {
*a++ ^= *b++;
} while (--bs);
}
static void xor_quad(u8 *dst, const u8 *src, unsigned int bs)
{
u32 *a = (u32 *)dst;
u32 *b = (u32 *)src;
do {
*a++ ^= *b++;
} while ((bs -= 4));
}
static void xor_64(u8 *a, const u8 *b, unsigned int bs)
{
((u32 *)a)[0] ^= ((u32 *)b)[0];
((u32 *)a)[1] ^= ((u32 *)b)[1];
}
static void xor_128(u8 *a, const u8 *b, unsigned int bs)
{
((u32 *)a)[0] ^= ((u32 *)b)[0];
((u32 *)a)[1] ^= ((u32 *)b)[1];
((u32 *)a)[2] ^= ((u32 *)b)[2];
((u32 *)a)[3] ^= ((u32 *)b)[3];
}
static int crypto_pcbc_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_instance *inst = (void *)tfm->__crt_alg;
struct crypto_spawn *spawn = crypto_instance_ctx(inst);
struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(tfm);
struct crypto_cipher *cipher;
switch (crypto_tfm_alg_blocksize(tfm)) {
case 8:
ctx->xor = xor_64;
break;
case 16:
ctx->xor = xor_128;
break;
default:
if (crypto_tfm_alg_blocksize(tfm) % 4)
ctx->xor = xor_byte;
else
ctx->xor = xor_quad;
}
cipher = crypto_spawn_cipher(spawn);
if (IS_ERR(cipher))
return PTR_ERR(cipher);
ctx->child = cipher;
return 0;
}
static void crypto_pcbc_exit_tfm(struct crypto_tfm *tfm)
{
struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(tfm);
crypto_free_cipher(ctx->child);
}
static struct crypto_instance *crypto_pcbc_alloc(struct rtattr **tb)
{
struct crypto_instance *inst;
struct crypto_alg *alg;
int err;
err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
if (err)
return ERR_PTR(err);
alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
CRYPTO_ALG_TYPE_MASK);
if (IS_ERR(alg))
return ERR_PTR(PTR_ERR(alg));
inst = crypto_alloc_instance("pcbc", alg);
if (IS_ERR(inst))
goto out_put_alg;
inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
inst->alg.cra_priority = alg->cra_priority;
inst->alg.cra_blocksize = alg->cra_blocksize;
inst->alg.cra_alignmask = alg->cra_alignmask;
inst->alg.cra_type = &crypto_blkcipher_type;
if (!(alg->cra_blocksize % 4))
inst->alg.cra_alignmask |= 3;
inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
inst->alg.cra_ctxsize = sizeof(struct crypto_pcbc_ctx);
inst->alg.cra_init = crypto_pcbc_init_tfm;
inst->alg.cra_exit = crypto_pcbc_exit_tfm;
inst->alg.cra_blkcipher.setkey = crypto_pcbc_setkey;
inst->alg.cra_blkcipher.encrypt = crypto_pcbc_encrypt;
inst->alg.cra_blkcipher.decrypt = crypto_pcbc_decrypt;
out_put_alg:
crypto_mod_put(alg);
return inst;
}
static void crypto_pcbc_free(struct crypto_instance *inst)
{
crypto_drop_spawn(crypto_instance_ctx(inst));
kfree(inst);
}
static struct crypto_template crypto_pcbc_tmpl = {
.name = "pcbc",
.alloc = crypto_pcbc_alloc,
.free = crypto_pcbc_free,
.module = THIS_MODULE,
};
static int __init crypto_pcbc_module_init(void)
{
return crypto_register_template(&crypto_pcbc_tmpl);
}
static void __exit crypto_pcbc_module_exit(void)
{
crypto_unregister_template(&crypto_pcbc_tmpl);
}
module_init(crypto_pcbc_module_init);
module_exit(crypto_pcbc_module_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("PCBC block cipher algorithm");
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