![Herbert Xu](/assets/img/avatar_default.png)
Although xcbc was converted to shash, it didn't obey the new requirement that all hash state must be stored in the descriptor rather than the transform. This patch fixes this issue and also optimises away the rekeying by precomputing K2 and K3 within setkey. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
286 lines
7.1 KiB
C
286 lines
7.1 KiB
C
/*
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* Copyright (C)2006 USAGI/WIDE Project
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Author:
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* Kazunori Miyazawa <miyazawa@linux-ipv6.org>
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*/
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#include <crypto/internal/hash.h>
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#include <linux/err.h>
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#include <linux/kernel.h>
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static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101,
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0x02020202, 0x02020202, 0x02020202, 0x02020202,
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0x03030303, 0x03030303, 0x03030303, 0x03030303};
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/*
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* +------------------------
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* | <parent tfm>
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* +------------------------
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* | xcbc_tfm_ctx
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* +------------------------
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* | consts (block size * 2)
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* +------------------------
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*/
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struct xcbc_tfm_ctx {
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struct crypto_cipher *child;
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u8 ctx[];
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};
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/*
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* +------------------------
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* | <shash desc>
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* +------------------------
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* | xcbc_desc_ctx
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* +------------------------
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* | odds (block size)
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* +------------------------
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* | prev (block size)
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* +------------------------
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*/
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struct xcbc_desc_ctx {
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unsigned int len;
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u8 ctx[];
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};
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static int crypto_xcbc_digest_setkey(struct crypto_shash *parent,
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const u8 *inkey, unsigned int keylen)
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{
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unsigned long alignmask = crypto_shash_alignmask(parent);
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struct xcbc_tfm_ctx *ctx = crypto_shash_ctx(parent);
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int bs = crypto_shash_blocksize(parent);
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u8 *consts = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
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int err = 0;
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u8 key1[bs];
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if ((err = crypto_cipher_setkey(ctx->child, inkey, keylen)))
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return err;
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crypto_cipher_encrypt_one(ctx->child, consts, (u8 *)ks + bs);
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crypto_cipher_encrypt_one(ctx->child, consts + bs, (u8 *)ks + bs * 2);
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crypto_cipher_encrypt_one(ctx->child, key1, (u8 *)ks);
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return crypto_cipher_setkey(ctx->child, key1, bs);
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}
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static int crypto_xcbc_digest_init(struct shash_desc *pdesc)
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{
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unsigned long alignmask = crypto_shash_alignmask(pdesc->tfm);
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struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
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int bs = crypto_shash_blocksize(pdesc->tfm);
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u8 *prev = PTR_ALIGN(&ctx->ctx[0], alignmask + 1) + bs;
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ctx->len = 0;
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memset(prev, 0, bs);
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return 0;
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}
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static int crypto_xcbc_digest_update(struct shash_desc *pdesc, const u8 *p,
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unsigned int len)
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{
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struct crypto_shash *parent = pdesc->tfm;
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unsigned long alignmask = crypto_shash_alignmask(parent);
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struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
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struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
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struct crypto_cipher *tfm = tctx->child;
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int bs = crypto_shash_blocksize(parent);
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u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
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u8 *prev = odds + bs;
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/* checking the data can fill the block */
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if ((ctx->len + len) <= bs) {
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memcpy(odds + ctx->len, p, len);
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ctx->len += len;
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return 0;
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}
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/* filling odds with new data and encrypting it */
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memcpy(odds + ctx->len, p, bs - ctx->len);
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len -= bs - ctx->len;
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p += bs - ctx->len;
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crypto_xor(prev, odds, bs);
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crypto_cipher_encrypt_one(tfm, prev, prev);
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/* clearing the length */
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ctx->len = 0;
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/* encrypting the rest of data */
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while (len > bs) {
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crypto_xor(prev, p, bs);
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crypto_cipher_encrypt_one(tfm, prev, prev);
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p += bs;
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len -= bs;
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}
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/* keeping the surplus of blocksize */
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if (len) {
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memcpy(odds, p, len);
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ctx->len = len;
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}
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return 0;
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}
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static int crypto_xcbc_digest_final(struct shash_desc *pdesc, u8 *out)
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{
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struct crypto_shash *parent = pdesc->tfm;
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unsigned long alignmask = crypto_shash_alignmask(parent);
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struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
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struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
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struct crypto_cipher *tfm = tctx->child;
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int bs = crypto_shash_blocksize(parent);
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u8 *consts = PTR_ALIGN(&tctx->ctx[0], alignmask + 1);
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u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
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u8 *prev = odds + bs;
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unsigned int offset = 0;
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if (ctx->len != bs) {
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unsigned int rlen;
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u8 *p = odds + ctx->len;
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*p = 0x80;
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p++;
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rlen = bs - ctx->len -1;
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if (rlen)
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memset(p, 0, rlen);
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offset += bs;
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}
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crypto_xor(prev, odds, bs);
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crypto_xor(prev, consts + offset, bs);
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crypto_cipher_encrypt_one(tfm, out, prev);
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return 0;
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}
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static int xcbc_init_tfm(struct crypto_tfm *tfm)
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{
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struct crypto_cipher *cipher;
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struct crypto_instance *inst = (void *)tfm->__crt_alg;
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struct crypto_spawn *spawn = crypto_instance_ctx(inst);
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struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
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cipher = crypto_spawn_cipher(spawn);
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if (IS_ERR(cipher))
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return PTR_ERR(cipher);
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ctx->child = cipher;
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return 0;
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};
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static void xcbc_exit_tfm(struct crypto_tfm *tfm)
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{
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struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
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crypto_free_cipher(ctx->child);
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}
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static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
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{
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struct shash_instance *inst;
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struct crypto_alg *alg;
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int err;
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err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
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if (err)
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return err;
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alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
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CRYPTO_ALG_TYPE_MASK);
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if (IS_ERR(alg))
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return PTR_ERR(alg);
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switch(alg->cra_blocksize) {
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case 16:
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break;
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default:
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goto out_put_alg;
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}
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inst = shash_alloc_instance("xcbc", alg);
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err = PTR_ERR(inst);
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if (IS_ERR(inst))
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goto out_put_alg;
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err = crypto_init_spawn(shash_instance_ctx(inst), alg,
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shash_crypto_instance(inst),
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CRYPTO_ALG_TYPE_MASK);
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if (err)
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goto out_free_inst;
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inst->alg.base.cra_priority = alg->cra_priority;
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inst->alg.base.cra_blocksize = alg->cra_blocksize;
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inst->alg.base.cra_alignmask = alg->cra_alignmask | 3;
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inst->alg.digestsize = alg->cra_blocksize;
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inst->alg.descsize = ALIGN(sizeof(struct xcbc_desc_ctx),
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crypto_tfm_ctx_alignment()) +
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(alg->cra_alignmask &
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~(crypto_tfm_ctx_alignment() - 1)) +
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alg->cra_blocksize * 2;
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inst->alg.base.cra_ctxsize = ALIGN(sizeof(struct xcbc_tfm_ctx),
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alg->cra_alignmask) +
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alg->cra_blocksize * 2;
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inst->alg.base.cra_init = xcbc_init_tfm;
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inst->alg.base.cra_exit = xcbc_exit_tfm;
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inst->alg.init = crypto_xcbc_digest_init;
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inst->alg.update = crypto_xcbc_digest_update;
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inst->alg.final = crypto_xcbc_digest_final;
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inst->alg.setkey = crypto_xcbc_digest_setkey;
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err = shash_register_instance(tmpl, inst);
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if (err) {
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out_free_inst:
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shash_free_instance(shash_crypto_instance(inst));
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}
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out_put_alg:
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crypto_mod_put(alg);
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return err;
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}
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static struct crypto_template crypto_xcbc_tmpl = {
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.name = "xcbc",
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.create = xcbc_create,
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.free = shash_free_instance,
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.module = THIS_MODULE,
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};
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static int __init crypto_xcbc_module_init(void)
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{
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return crypto_register_template(&crypto_xcbc_tmpl);
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}
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static void __exit crypto_xcbc_module_exit(void)
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{
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crypto_unregister_template(&crypto_xcbc_tmpl);
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}
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module_init(crypto_xcbc_module_init);
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module_exit(crypto_xcbc_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("XCBC keyed hash algorithm");
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