345 lines
8.6 KiB
C
345 lines
8.6 KiB
C
|
/*
|
||
|
|
* CBC: Cipher Block Chaining mode
|
||
|
|
*
|
||
|
|
* 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_cbc_ctx {
|
||
|
|
struct crypto_cipher *child;
|
||
|
|
void (*xor)(u8 *dst, const u8 *src, unsigned int bs);
|
||
|
|
};
|
||
|
|
|
||
|
|
static int crypto_cbc_setkey(struct crypto_tfm *parent, const u8 *key,
|
||
|
|
unsigned int keylen)
|
||
|
|
{
|
||
|
|
struct crypto_cbc_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_cbc_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);
|
||
|
|
|
||
|
|
src += bsize;
|
||
|
|
dst += bsize;
|
||
|
|
} while ((nbytes -= bsize) >= bsize);
|
||
|
|
|
||
|
|
return nbytes;
|
||
|
|
}
|
||
|
|
|
||
|
|
static int crypto_cbc_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;
|
||
|
|
|
||
|
|
do {
|
||
|
|
xor(src, iv, bsize);
|
||
|
|
fn(crypto_cipher_tfm(tfm), src, src);
|
||
|
|
iv = src;
|
||
|
|
|
||
|
|
src += bsize;
|
||
|
|
} while ((nbytes -= bsize) >= bsize);
|
||
|
|
|
||
|
|
memcpy(walk->iv, iv, bsize);
|
||
|
|
|
||
|
|
return nbytes;
|
||
|
|
}
|
||
|
|
|
||
|
|
static int crypto_cbc_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_cbc_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_cbc_encrypt_inplace(desc, &walk, child,
|
||
|
|
xor);
|
||
|
|
else
|
||
|
|
nbytes = crypto_cbc_encrypt_segment(desc, &walk, child,
|
||
|
|
xor);
|
||
|
|
err = blkcipher_walk_done(desc, &walk, nbytes);
|
||
|
|
}
|
||
|
|
|
||
|
|
return err;
|
||
|
|
}
|
||
|
|
|
||
|
|
static int crypto_cbc_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);
|
||
|
|
iv = src;
|
||
|
|
|
||
|
|
src += bsize;
|
||
|
|
dst += bsize;
|
||
|
|
} while ((nbytes -= bsize) >= bsize);
|
||
|
|
|
||
|
|
memcpy(walk->iv, iv, bsize);
|
||
|
|
|
||
|
|
return nbytes;
|
||
|
|
}
|
||
|
|
|
||
|
|
static int crypto_cbc_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 long alignmask = crypto_cipher_alignmask(tfm);
|
||
|
|
unsigned int nbytes = walk->nbytes;
|
||
|
|
u8 *src = walk->src.virt.addr;
|
||
|
|
u8 stack[bsize + alignmask];
|
||
|
|
u8 *first_iv = (u8 *)ALIGN((unsigned long)stack, alignmask + 1);
|
||
|
|
|
||
|
|
memcpy(first_iv, walk->iv, bsize);
|
||
|
|
|
||
|
|
/* Start of the last block. */
|
||
|
|
src += nbytes - nbytes % bsize - bsize;
|
||
|
|
memcpy(walk->iv, src, bsize);
|
||
|
|
|
||
|
|
for (;;) {
|
||
|
|
fn(crypto_cipher_tfm(tfm), src, src);
|
||
|
|
if ((nbytes -= bsize) < bsize)
|
||
|
|
break;
|
||
|
|
xor(src, src - bsize, bsize);
|
||
|
|
src -= bsize;
|
||
|
|
}
|
||
|
|
|
||
|
|
xor(src, first_iv, bsize);
|
||
|
|
|
||
|
|
return nbytes;
|
||
|
|
}
|
||
|
|
|
||
|
|
static int crypto_cbc_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_cbc_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_cbc_decrypt_inplace(desc, &walk, child,
|
||
|
|
xor);
|
||
|
|
else
|
||
|
|
nbytes = crypto_cbc_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_cbc_init_tfm(struct crypto_tfm *tfm)
|
||
|
|
{
|
||
|
|
struct crypto_instance *inst = (void *)tfm->__crt_alg;
|
||
|
|
struct crypto_spawn *spawn = crypto_instance_ctx(inst);
|
||
|
|
struct crypto_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
|
||
|
|
|
||
|
|
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;
|
||
|
|
}
|
||
|
|
|
||
|
|
tfm = crypto_spawn_tfm(spawn);
|
||
|
|
if (IS_ERR(tfm))
|
||
|
|
return PTR_ERR(tfm);
|
||
|
|
|
||
|
|
ctx->child = crypto_cipher_cast(tfm);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static void crypto_cbc_exit_tfm(struct crypto_tfm *tfm)
|
||
|
|
{
|
||
|
|
struct crypto_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
|
||
|
|
crypto_free_cipher(ctx->child);
|
||
|
|
}
|
||
|
|
|
||
|
|
static struct crypto_instance *crypto_cbc_alloc(void *param, unsigned int len)
|
||
|
|
{
|
||
|
|
struct crypto_instance *inst;
|
||
|
|
struct crypto_alg *alg;
|
||
|
|
|
||
|
|
alg = crypto_get_attr_alg(param, len, CRYPTO_ALG_TYPE_CIPHER,
|
||
|
|
CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC);
|
||
|
|
if (IS_ERR(alg))
|
||
|
|
return ERR_PTR(PTR_ERR(alg));
|
||
|
|
|
||
|
|
inst = crypto_alloc_instance("cbc", 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_cbc_ctx);
|
||
|
|
|
||
|
|
inst->alg.cra_init = crypto_cbc_init_tfm;
|
||
|
|
inst->alg.cra_exit = crypto_cbc_exit_tfm;
|
||
|
|
|
||
|
|
inst->alg.cra_blkcipher.setkey = crypto_cbc_setkey;
|
||
|
|
inst->alg.cra_blkcipher.encrypt = crypto_cbc_encrypt;
|
||
|
|
inst->alg.cra_blkcipher.decrypt = crypto_cbc_decrypt;
|
||
|
|
|
||
|
|
out_put_alg:
|
||
|
|
crypto_mod_put(alg);
|
||
|
|
return inst;
|
||
|
|
}
|
||
|
|
|
||
|
|
static void crypto_cbc_free(struct crypto_instance *inst)
|
||
|
|
{
|
||
|
|
crypto_drop_spawn(crypto_instance_ctx(inst));
|
||
|
|
kfree(inst);
|
||
|
|
}
|
||
|
|
|
||
|
|
static struct crypto_template crypto_cbc_tmpl = {
|
||
|
|
.name = "cbc",
|
||
|
|
.alloc = crypto_cbc_alloc,
|
||
|
|
.free = crypto_cbc_free,
|
||
|
|
.module = THIS_MODULE,
|
||
|
|
};
|
||
|
|
|
||
|
|
static int __init crypto_cbc_module_init(void)
|
||
|
|
{
|
||
|
|
return crypto_register_template(&crypto_cbc_tmpl);
|
||
|
|
}
|
||
|
|
|
||
|
|
static void __exit crypto_cbc_module_exit(void)
|
||
|
|
{
|
||
|
|
crypto_unregister_template(&crypto_cbc_tmpl);
|
||
|
|
}
|
||
|
|
|
||
|
|
module_init(crypto_cbc_module_init);
|
||
|
|
module_exit(crypto_cbc_module_exit);
|
||
|
|
|
||
|
|
MODULE_LICENSE("GPL");
|
||
|
|
MODULE_DESCRIPTION("CBC block cipher algorithm");
|