blowfish_glue.c

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/*
 * Glue Code for assembler optimized version of Blowfish
 *
 * Copyright (c) 2011 Jussi Kivilinna <[email protected]>
 *
 * CBC & ECB parts based on code (crypto/cbc.c,ecb.c) by:
 *   Copyright (c) 2006 Herbert Xu <[email protected]>
 * CTR part based on code (crypto/ctr.c) by:
 *   (C) Copyright IBM Corp. 2007 - Joy Latten <[email protected]>
 *
 * 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
 *
 */

#include <asm/processor.h>
#include <crypto/blowfish.h>
#include <linux/crypto.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/types.h>
#include <crypto/algapi.h>

/* regular block cipher functions */
asmlinkage void __blowfish_enc_blk(struct bf_ctx *ctx, u8 *dst, const u8 *src,
                   bool xor);
asmlinkage void blowfish_dec_blk(struct bf_ctx *ctx, u8 *dst, const u8 *src);

/* 4-way parallel cipher functions */
asmlinkage void __blowfish_enc_blk_4way(struct bf_ctx *ctx, u8 *dst,
                    const u8 *src, bool xor);
asmlinkage void blowfish_dec_blk_4way(struct bf_ctx *ctx, u8 *dst,
                      const u8 *src);

static inline void blowfish_enc_blk(struct bf_ctx *ctx, u8 *dst, const u8 *src)
{
    __blowfish_enc_blk(ctx, dst, src, false);
}

static inline void blowfish_enc_blk_xor(struct bf_ctx *ctx, u8 *dst,
                    const u8 *src)
{
    __blowfish_enc_blk(ctx, dst, src, true);
}

static inline void blowfish_enc_blk_4way(struct bf_ctx *ctx, u8 *dst,
                     const u8 *src)
{
    __blowfish_enc_blk_4way(ctx, dst, src, false);
}

static inline void blowfish_enc_blk_xor_4way(struct bf_ctx *ctx, u8 *dst,
                      const u8 *src)
{
    __blowfish_enc_blk_4way(ctx, dst, src, true);
}

static void blowfish_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
    blowfish_enc_blk(crypto_tfm_ctx(tfm), dst, src);
}

static void blowfish_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
    blowfish_dec_blk(crypto_tfm_ctx(tfm), dst, src);
}

static int ecb_crypt(struct blkcipher_desc *desc, struct blkcipher_walk *walk,
             void (*fn)(struct bf_ctx *, u8 *, const u8 *),
             void (*fn_4way)(struct bf_ctx *, u8 *, const u8 *))
{
    struct bf_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
    unsigned int bsize = BF_BLOCK_SIZE;
    unsigned int nbytes;
    int err;

    err = blkcipher_walk_virt(desc, walk);

    while ((nbytes = walk->nbytes)) {
        u8 *wsrc = walk->src.virt.addr;
        u8 *wdst = walk->dst.virt.addr;

        /* Process four block batch */
        if (nbytes >= bsize * 4) {
            do {
                fn_4way(ctx, wdst, wsrc);

                wsrc += bsize * 4;
                wdst += bsize * 4;
                nbytes -= bsize * 4;
            } while (nbytes >= bsize * 4);

            if (nbytes < bsize)
                goto done;
        }

        /* Handle leftovers */
        do {
            fn(ctx, wdst, wsrc);

            wsrc += bsize;
            wdst += bsize;
            nbytes -= bsize;
        } while (nbytes >= bsize);

done:
        err = blkcipher_walk_done(desc, walk, nbytes);
    }

    return err;
}

static int ecb_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
               struct scatterlist *src, unsigned int nbytes)
{
    struct blkcipher_walk walk;

    blkcipher_walk_init(&walk, dst, src, nbytes);
    return ecb_crypt(desc, &walk, blowfish_enc_blk, blowfish_enc_blk_4way);
}

static int ecb_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
               struct scatterlist *src, unsigned int nbytes)
{
    struct blkcipher_walk walk;

    blkcipher_walk_init(&walk, dst, src, nbytes);
    return ecb_crypt(desc, &walk, blowfish_dec_blk, blowfish_dec_blk_4way);
}

static unsigned int __cbc_encrypt(struct blkcipher_desc *desc,
                  struct blkcipher_walk *walk)
{
    struct bf_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
    unsigned int bsize = BF_BLOCK_SIZE;
    unsigned int nbytes = walk->nbytes;
    u64 *src = (u64 *)walk->src.virt.addr;
    u64 *dst = (u64 *)walk->dst.virt.addr;
    u64 *iv = (u64 *)walk->iv;

    do {
        *dst = *src ^ *iv;
        blowfish_enc_blk(ctx, (u8 *)dst, (u8 *)dst);
        iv = dst;

        src += 1;
        dst += 1;
        nbytes -= bsize;
    } while (nbytes >= bsize);

    *(u64 *)walk->iv = *iv;
    return nbytes;
}

static int cbc_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
               struct scatterlist *src, unsigned int nbytes)
{
    struct blkcipher_walk walk;
    int err;

    blkcipher_walk_init(&walk, dst, src, nbytes);
    err = blkcipher_walk_virt(desc, &walk);

    while ((nbytes = walk.nbytes)) {
        nbytes = __cbc_encrypt(desc, &walk);
        err = blkcipher_walk_done(desc, &walk, nbytes);
    }

    return err;
}

static unsigned int __cbc_decrypt(struct blkcipher_desc *desc,
                  struct blkcipher_walk *walk)
{
    struct bf_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
    unsigned int bsize = BF_BLOCK_SIZE;
    unsigned int nbytes = walk->nbytes;
    u64 *src = (u64 *)walk->src.virt.addr;
    u64 *dst = (u64 *)walk->dst.virt.addr;
    u64 ivs[4 - 1];
    u64 last_iv;

    /* Start of the last block. */
    src += nbytes / bsize - 1;
    dst += nbytes / bsize - 1;

    last_iv = *src;

    /* Process four block batch */
    if (nbytes >= bsize * 4) {
        do {
            nbytes -= bsize * 4 - bsize;
            src -= 4 - 1;
            dst -= 4 - 1;

            ivs[0] = src[0];
            ivs[1] = src[1];
            ivs[2] = src[2];

            blowfish_dec_blk_4way(ctx, (u8 *)dst, (u8 *)src);

            dst[1] ^= ivs[0];
            dst[2] ^= ivs[1];
            dst[3] ^= ivs[2];

            nbytes -= bsize;
            if (nbytes < bsize)
                goto done;

            *dst ^= *(src - 1);
            src -= 1;
            dst -= 1;
        } while (nbytes >= bsize * 4);

        if (nbytes < bsize)
            goto done;
    }

    /* Handle leftovers */
    for (;;) {
        blowfish_dec_blk(ctx, (u8 *)dst, (u8 *)src);

        nbytes -= bsize;
        if (nbytes < bsize)
            break;

        *dst ^= *(src - 1);
        src -= 1;
        dst -= 1;
    }

done:
    *dst ^= *(u64 *)walk->iv;
    *(u64 *)walk->iv = last_iv;

    return nbytes;
}

static int cbc_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
               struct scatterlist *src, unsigned int nbytes)
{
    struct blkcipher_walk walk;
    int err;

    blkcipher_walk_init(&walk, dst, src, nbytes);
    err = blkcipher_walk_virt(desc, &walk);

    while ((nbytes = walk.nbytes)) {
        nbytes = __cbc_decrypt(desc, &walk);
        err = blkcipher_walk_done(desc, &walk, nbytes);
    }

    return err;
}

static void ctr_crypt_final(struct bf_ctx *ctx, struct blkcipher_walk *walk)
{
    u8 *ctrblk = walk->iv;
    u8 keystream[BF_BLOCK_SIZE];
    u8 *src = walk->src.virt.addr;
    u8 *dst = walk->dst.virt.addr;
    unsigned int nbytes = walk->nbytes;

    blowfish_enc_blk(ctx, keystream, ctrblk);
    crypto_xor(keystream, src, nbytes);
    memcpy(dst, keystream, nbytes);

    crypto_inc(ctrblk, BF_BLOCK_SIZE);
}

static unsigned int __ctr_crypt(struct blkcipher_desc *desc,
                struct blkcipher_walk *walk)
{
    struct bf_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
    unsigned int bsize = BF_BLOCK_SIZE;
    unsigned int nbytes = walk->nbytes;
    u64 *src = (u64 *)walk->src.virt.addr;
    u64 *dst = (u64 *)walk->dst.virt.addr;
    u64 ctrblk = be64_to_cpu(*(__be64 *)walk->iv);
    __be64 ctrblocks[4];

    /* Process four block batch */
    if (nbytes >= bsize * 4) {
        do {
            if (dst != src) {
                dst[0] = src[0];
                dst[1] = src[1];
                dst[2] = src[2];
                dst[3] = src[3];
            }

            /* create ctrblks for parallel encrypt */
            ctrblocks[0] = cpu_to_be64(ctrblk++);
            ctrblocks[1] = cpu_to_be64(ctrblk++);
            ctrblocks[2] = cpu_to_be64(ctrblk++);
            ctrblocks[3] = cpu_to_be64(ctrblk++);

            blowfish_enc_blk_xor_4way(ctx, (u8 *)dst,
                          (u8 *)ctrblocks);

            src += 4;
            dst += 4;
        } while ((nbytes -= bsize * 4) >= bsize * 4);

        if (nbytes < bsize)
            goto done;
    }

    /* Handle leftovers */
    do {
        if (dst != src)
            *dst = *src;

        ctrblocks[0] = cpu_to_be64(ctrblk++);

        blowfish_enc_blk_xor(ctx, (u8 *)dst, (u8 *)ctrblocks);

        src += 1;
        dst += 1;
    } while ((nbytes -= bsize) >= bsize);

done:
    *(__be64 *)walk->iv = cpu_to_be64(ctrblk);
    return nbytes;
}

static int ctr_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
             struct scatterlist *src, unsigned int nbytes)
{
    struct blkcipher_walk walk;
    int err;

    blkcipher_walk_init(&walk, dst, src, nbytes);
    err = blkcipher_walk_virt_block(desc, &walk, BF_BLOCK_SIZE);

    while ((nbytes = walk.nbytes) >= BF_BLOCK_SIZE) {
        nbytes = __ctr_crypt(desc, &walk);
        err = blkcipher_walk_done(desc, &walk, nbytes);
    }

    if (walk.nbytes) {
        ctr_crypt_final(crypto_blkcipher_ctx(desc->tfm), &walk);
        err = blkcipher_walk_done(desc, &walk, 0);
    }

    return err;
}

static struct crypto_alg bf_algs[4] = { {
    .cra_name       = "blowfish",
    .cra_driver_name    = "blowfish-asm",
    .cra_priority       = 200,
    .cra_flags      = CRYPTO_ALG_TYPE_CIPHER,
    .cra_blocksize      = BF_BLOCK_SIZE,
    .cra_ctxsize        = sizeof(struct bf_ctx),
    .cra_alignmask      = 0,
    .cra_module     = THIS_MODULE,
    .cra_u = {
        .cipher = {
            .cia_min_keysize    = BF_MIN_KEY_SIZE,
            .cia_max_keysize    = BF_MAX_KEY_SIZE,
            .cia_setkey     = blowfish_setkey,
            .cia_encrypt        = blowfish_encrypt,
            .cia_decrypt        = blowfish_decrypt,
        }
    }
}, {
    .cra_name       = "ecb(blowfish)",
    .cra_driver_name    = "ecb-blowfish-asm",
    .cra_priority       = 300,
    .cra_flags      = CRYPTO_ALG_TYPE_BLKCIPHER,
    .cra_blocksize      = BF_BLOCK_SIZE,
    .cra_ctxsize        = sizeof(struct bf_ctx),
    .cra_alignmask      = 0,
    .cra_type       = &crypto_blkcipher_type,
    .cra_module     = THIS_MODULE,
    .cra_u = {
        .blkcipher = {
            .min_keysize    = BF_MIN_KEY_SIZE,
            .max_keysize    = BF_MAX_KEY_SIZE,
            .setkey     = blowfish_setkey,
            .encrypt    = ecb_encrypt,
            .decrypt    = ecb_decrypt,
        },
    },
}, {
    .cra_name       = "cbc(blowfish)",
    .cra_driver_name    = "cbc-blowfish-asm",
    .cra_priority       = 300,
    .cra_flags      = CRYPTO_ALG_TYPE_BLKCIPHER,
    .cra_blocksize      = BF_BLOCK_SIZE,
    .cra_ctxsize        = sizeof(struct bf_ctx),
    .cra_alignmask      = 0,
    .cra_type       = &crypto_blkcipher_type,
    .cra_module     = THIS_MODULE,
    .cra_u = {
        .blkcipher = {
            .min_keysize    = BF_MIN_KEY_SIZE,
            .max_keysize    = BF_MAX_KEY_SIZE,
            .ivsize     = BF_BLOCK_SIZE,
            .setkey     = blowfish_setkey,
            .encrypt    = cbc_encrypt,
            .decrypt    = cbc_decrypt,
        },
    },
}, {
    .cra_name       = "ctr(blowfish)",
    .cra_driver_name    = "ctr-blowfish-asm",
    .cra_priority       = 300,
    .cra_flags      = CRYPTO_ALG_TYPE_BLKCIPHER,
    .cra_blocksize      = 1,
    .cra_ctxsize        = sizeof(struct bf_ctx),
    .cra_alignmask      = 0,
    .cra_type       = &crypto_blkcipher_type,
    .cra_module     = THIS_MODULE,
    .cra_u = {
        .blkcipher = {
            .min_keysize    = BF_MIN_KEY_SIZE,
            .max_keysize    = BF_MAX_KEY_SIZE,
            .ivsize     = BF_BLOCK_SIZE,
            .setkey     = blowfish_setkey,
            .encrypt    = ctr_crypt,
            .decrypt    = ctr_crypt,
        },
    },
} };

static bool is_blacklisted_cpu(void)
{
    if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
        return false;

    if (boot_cpu_data.x86 == 0x0f) {
        /*
         * On Pentium 4, blowfish-x86_64 is slower than generic C
         * implementation because use of 64bit rotates (which are really
         * slow on P4). Therefore blacklist P4s.
         */
        return true;
    }

    return false;
}

static int force;
module_param(force, int, 0);
MODULE_PARM_DESC(force, "Force module load, ignore CPU blacklist");

static int __init init(void)
{
    if (!force && is_blacklisted_cpu()) {
        printk(KERN_INFO
            "blowfish-x86_64: performance on this CPU "
            "would be suboptimal: disabling "
            "blowfish-x86_64.\n");
        return -ENODEV;
    }

    return crypto_register_algs(bf_algs, ARRAY_SIZE(bf_algs));
}

static void __exit fini(void)
{
    crypto_unregister_algs(bf_algs, ARRAY_SIZE(bf_algs));
}

module_init(init);
module_exit(fini);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Blowfish Cipher Algorithm, asm optimized");
MODULE_ALIAS("blowfish");
MODULE_ALIAS("blowfish-asm");