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tag: v2.6.22-rc2
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/*
* Copyright (C)2006 USAGI/WIDE Project
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Author:
* Kazunori Miyazawa <miyazawa@linux-ipv6.org>
*/

#include <linux/crypto.h>
#include <linux/err.h>
#include <linux/hardirq.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/rtnetlink.h>
#include <linux/slab.h>
#include <linux/scatterlist.h>
#include "internal.h"

static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101,
0x02020202, 0x02020202, 0x02020202, 0x02020202,
0x03030303, 0x03030303, 0x03030303, 0x03030303};
/*
* +------------------------
* | <parent tfm>
* +------------------------
* | crypto_xcbc_ctx
* +------------------------
* | odds (block size)
* +------------------------
* | prev (block size)
* +------------------------
* | key (block size)
* +------------------------
* | consts (block size * 3)
* +------------------------
*/
struct crypto_xcbc_ctx {
struct crypto_cipher *child;
u8 *odds;
u8 *prev;
u8 *key;
u8 *consts;
void (*xor)(u8 *a, const u8 *b, unsigned int bs);
unsigned int keylen;
unsigned int len;
};

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_xcbc_digest_setkey(struct crypto_hash *parent,
struct crypto_xcbc_ctx *ctx)
{
int bs = crypto_hash_blocksize(parent);
int err = 0;
u8 key1[bs];

if ((err = crypto_cipher_setkey(ctx->child, ctx->key, ctx->keylen)))
return err;

crypto_cipher_encrypt_one(ctx->child, key1, ctx->consts);

return crypto_cipher_setkey(ctx->child, key1, bs);
}

static int crypto_xcbc_digest_setkey(struct crypto_hash *parent,
const u8 *inkey, unsigned int keylen)
{
struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(parent);

if (keylen != crypto_cipher_blocksize(ctx->child))
return -EINVAL;

ctx->keylen = keylen;
memcpy(ctx->key, inkey, keylen);
ctx->consts = (u8*)ks;

return _crypto_xcbc_digest_setkey(parent, ctx);
}

static int crypto_xcbc_digest_init(struct hash_desc *pdesc)
{
struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(pdesc->tfm);
int bs = crypto_hash_blocksize(pdesc->tfm);

ctx->len = 0;
memset(ctx->odds, 0, bs);
memset(ctx->prev, 0, bs);

return 0;
}

static int crypto_xcbc_digest_update2(struct hash_desc *pdesc,
struct scatterlist *sg,
unsigned int nbytes)
{
struct crypto_hash *parent = pdesc->tfm;
struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(parent);
struct crypto_cipher *tfm = ctx->child;
int bs = crypto_hash_blocksize(parent);
unsigned int i = 0;

do {

struct page *pg = sg[i].page;
unsigned int offset = sg[i].offset;
unsigned int slen = sg[i].length;

while (slen > 0) {
unsigned int len = min(slen, ((unsigned int)(PAGE_SIZE)) - offset);
char *p = crypto_kmap(pg, 0) + offset;

/* checking the data can fill the block */
if ((ctx->len + len) <= bs) {
memcpy(ctx->odds + ctx->len, p, len);
ctx->len += len;
slen -= len;

/* checking the rest of the page */
if (len + offset >= PAGE_SIZE) {
offset = 0;
pg++;
} else
offset += len;

crypto_kunmap(p, 0);
crypto_yield(pdesc->flags);
continue;
}

/* filling odds with new data and encrypting it */
memcpy(ctx->odds + ctx->len, p, bs - ctx->len);
len -= bs - ctx->len;
p += bs - ctx->len;

ctx->xor(ctx->prev, ctx->odds, bs);
crypto_cipher_encrypt_one(tfm, ctx->prev, ctx->prev);

/* clearing the length */
ctx->len = 0;

/* encrypting the rest of data */
while (len > bs) {
ctx->xor(ctx->prev, p, bs);
crypto_cipher_encrypt_one(tfm, ctx->prev,
ctx->prev);
p += bs;
len -= bs;
}

/* keeping the surplus of blocksize */
if (len) {
memcpy(ctx->odds, p, len);
ctx->len = len;
}
crypto_kunmap(p, 0);
crypto_yield(pdesc->flags);
slen -= min(slen, ((unsigned int)(PAGE_SIZE)) - offset);
offset = 0;
pg++;
}
nbytes-=sg[i].length;
i++;
} while (nbytes>0);

return 0;
}

static int crypto_xcbc_digest_update(struct hash_desc *pdesc,
struct scatterlist *sg,
unsigned int nbytes)
{
if (WARN_ON_ONCE(in_irq()))
return -EDEADLK;
return crypto_xcbc_digest_update2(pdesc, sg, nbytes);
}

static int crypto_xcbc_digest_final(struct hash_desc *pdesc, u8 *out)
{
struct crypto_hash *parent = pdesc->tfm;
struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(parent);
struct crypto_cipher *tfm = ctx->child;
int bs = crypto_hash_blocksize(parent);
int err = 0;

if (ctx->len == bs) {
u8 key2[bs];

if ((err = crypto_cipher_setkey(tfm, ctx->key, ctx->keylen)) != 0)
return err;

crypto_cipher_encrypt_one(tfm, key2,
(u8 *)(ctx->consts + bs));

ctx->xor(ctx->prev, ctx->odds, bs);
ctx->xor(ctx->prev, key2, bs);
_crypto_xcbc_digest_setkey(parent, ctx);

crypto_cipher_encrypt_one(tfm, out, ctx->prev);
} else {
u8 key3[bs];
unsigned int rlen;
u8 *p = ctx->odds + ctx->len;
*p = 0x80;
p++;

rlen = bs - ctx->len -1;
if (rlen)
memset(p, 0, rlen);

if ((err = crypto_cipher_setkey(tfm, ctx->key, ctx->keylen)) != 0)
return err;

crypto_cipher_encrypt_one(tfm, key3,
(u8 *)(ctx->consts + bs * 2));

ctx->xor(ctx->prev, ctx->odds, bs);
ctx->xor(ctx->prev, key3, bs);

_crypto_xcbc_digest_setkey(parent, ctx);

crypto_cipher_encrypt_one(tfm, out, ctx->prev);
}

return 0;
}

static int crypto_xcbc_digest(struct hash_desc *pdesc,
struct scatterlist *sg, unsigned int nbytes, u8 *out)
{
if (WARN_ON_ONCE(in_irq()))
return -EDEADLK;

crypto_xcbc_digest_init(pdesc);
crypto_xcbc_digest_update2(pdesc, sg, nbytes);
return crypto_xcbc_digest_final(pdesc, out);
}

static int xcbc_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_cipher *cipher;
struct crypto_instance *inst = (void *)tfm->__crt_alg;
struct crypto_spawn *spawn = crypto_instance_ctx(inst);
struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(__crypto_hash_cast(tfm));
int bs = crypto_hash_blocksize(__crypto_hash_cast(tfm));

cipher = crypto_spawn_cipher(spawn);
if (IS_ERR(cipher))
return PTR_ERR(cipher);

switch(bs) {
case 16:
ctx->xor = xor_128;
break;
default:
return -EINVAL;
}

ctx->child = cipher;
ctx->odds = (u8*)(ctx+1);
ctx->prev = ctx->odds + bs;
ctx->key = ctx->prev + bs;

return 0;
};

static void xcbc_exit_tfm(struct crypto_tfm *tfm)
{
struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(__crypto_hash_cast(tfm));
crypto_free_cipher(ctx->child);
}

static struct crypto_instance *xcbc_alloc(struct rtattr **tb)
{
struct crypto_instance *inst;
struct crypto_alg *alg;
int err;

err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_HASH);
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));

switch(alg->cra_blocksize) {
case 16:
break;
default:
return ERR_PTR(PTR_ERR(alg));
}

inst = crypto_alloc_instance("xcbc", alg);
if (IS_ERR(inst))
goto out_put_alg;

inst->alg.cra_flags = CRYPTO_ALG_TYPE_HASH;
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_hash_type;

inst->alg.cra_hash.digestsize =
(alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
CRYPTO_ALG_TYPE_HASH ? alg->cra_hash.digestsize :
alg->cra_blocksize;
inst->alg.cra_ctxsize = sizeof(struct crypto_xcbc_ctx) +
ALIGN(inst->alg.cra_blocksize * 3, sizeof(void *));
inst->alg.cra_init = xcbc_init_tfm;
inst->alg.cra_exit = xcbc_exit_tfm;

inst->alg.cra_hash.init = crypto_xcbc_digest_init;
inst->alg.cra_hash.update = crypto_xcbc_digest_update;
inst->alg.cra_hash.final = crypto_xcbc_digest_final;
inst->alg.cra_hash.digest = crypto_xcbc_digest;
inst->alg.cra_hash.setkey = crypto_xcbc_digest_setkey;

out_put_alg:
crypto_mod_put(alg);
return inst;
}

static void xcbc_free(struct crypto_instance *inst)
{
crypto_drop_spawn(crypto_instance_ctx(inst));
kfree(inst);
}

static struct crypto_template crypto_xcbc_tmpl = {
.name = "xcbc",
.alloc = xcbc_alloc,
.free = xcbc_free,
.module = THIS_MODULE,
};

static int __init crypto_xcbc_module_init(void)
{
return crypto_register_template(&crypto_xcbc_tmpl);
}

static void __exit crypto_xcbc_module_exit(void)
{
crypto_unregister_template(&crypto_xcbc_tmpl);
}

module_init(crypto_xcbc_module_init);
module_exit(crypto_xcbc_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("XCBC keyed hash algorithm");
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