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root/crypto/xcbc.c

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DEFINITIONS

This source file includes following definitions.
  1. xor_128
  2. _crypto_xcbc_digest_setkey
  3. crypto_xcbc_digest_setkey
  4. crypto_xcbc_digest_init
  5. crypto_xcbc_digest_update2
  6. crypto_xcbc_digest_update
  7. crypto_xcbc_digest_final
  8. crypto_xcbc_digest
  9. xcbc_init_tfm
  10. xcbc_exit_tfm
  11. xcbc_alloc
  12. xcbc_free
  13. crypto_xcbc_module_init
  14. crypto_xcbc_module_exit

/*
 * 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 <crypto/scatterwalk.h>
#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>

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);

        for (;;) {
                struct page *pg = sg_page(sg);
                unsigned int offset = sg->offset;
                unsigned int slen = sg->length;

                if (unlikely(slen > nbytes))
                        slen = nbytes;

                nbytes -= slen;

                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++;
                }

                if (!nbytes)
                        break;
                sg = scatterwalk_sg_next(sg);
        }

        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_CAST(alg);

        switch(alg->cra_blocksize) {
        case 16:
                break;
        default:
                inst = ERR_PTR(-EINVAL);
                goto out_put_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_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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