serpent_avx_glue.c

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/*
 * Glue Code for AVX assembler versions of Serpent Cipher
 *
 * Copyright (C) 2012 Johannes Goetzfried
 *     <[email protected]>
 *
 * Glue code based on serpent_sse2_glue.c by:
 *  Copyright (C) 2011 Jussi Kivilinna <[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 <linux/module.h>
#include <linux/hardirq.h>
#include <linux/types.h>
#include <linux/crypto.h>
#include <linux/err.h>
#include <crypto/algapi.h>
#include <crypto/serpent.h>
#include <crypto/cryptd.h>
#include <crypto/b128ops.h>
#include <crypto/ctr.h>
#include <crypto/lrw.h>
#include <crypto/xts.h>
#include <asm/xcr.h>
#include <asm/xsave.h>
#include <asm/crypto/serpent-avx.h>
#include <asm/crypto/ablk_helper.h>
#include <asm/crypto/glue_helper.h>

static void serpent_decrypt_cbc_xway(void *ctx, u128 *dst, const u128 *src)
{
    u128 ivs[SERPENT_PARALLEL_BLOCKS - 1];
    unsigned int j;

    for (j = 0; j < SERPENT_PARALLEL_BLOCKS - 1; j++)
        ivs[j] = src[j];

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

    for (j = 0; j < SERPENT_PARALLEL_BLOCKS - 1; j++)
        u128_xor(dst + (j + 1), dst + (j + 1), ivs + j);
}

static void serpent_crypt_ctr(void *ctx, u128 *dst, const u128 *src, u128 *iv)
{
    be128 ctrblk;

    u128_to_be128(&ctrblk, iv);
    u128_inc(iv);

    __serpent_encrypt(ctx, (u8 *)&ctrblk, (u8 *)&ctrblk);
    u128_xor(dst, src, (u128 *)&ctrblk);
}

static void serpent_crypt_ctr_xway(void *ctx, u128 *dst, const u128 *src,
                   u128 *iv)
{
    be128 ctrblks[SERPENT_PARALLEL_BLOCKS];
    unsigned int i;

    for (i = 0; i < SERPENT_PARALLEL_BLOCKS; i++) {
        if (dst != src)
            dst[i] = src[i];

        u128_to_be128(&ctrblks[i], iv);
        u128_inc(iv);
    }

    serpent_enc_blk_xway_xor(ctx, (u8 *)dst, (u8 *)ctrblks);
}

static const struct common_glue_ctx serpent_enc = {
    .num_funcs = 2,
    .fpu_blocks_limit = SERPENT_PARALLEL_BLOCKS,

    .funcs = { {
        .num_blocks = SERPENT_PARALLEL_BLOCKS,
        .fn_u = { .ecb = GLUE_FUNC_CAST(serpent_enc_blk_xway) }
    }, {
        .num_blocks = 1,
        .fn_u = { .ecb = GLUE_FUNC_CAST(__serpent_encrypt) }
    } }
};

static const struct common_glue_ctx serpent_ctr = {
    .num_funcs = 2,
    .fpu_blocks_limit = SERPENT_PARALLEL_BLOCKS,

    .funcs = { {
        .num_blocks = SERPENT_PARALLEL_BLOCKS,
        .fn_u = { .ctr = GLUE_CTR_FUNC_CAST(serpent_crypt_ctr_xway) }
    }, {
        .num_blocks = 1,
        .fn_u = { .ctr = GLUE_CTR_FUNC_CAST(serpent_crypt_ctr) }
    } }
};

static const struct common_glue_ctx serpent_dec = {
    .num_funcs = 2,
    .fpu_blocks_limit = SERPENT_PARALLEL_BLOCKS,

    .funcs = { {
        .num_blocks = SERPENT_PARALLEL_BLOCKS,
        .fn_u = { .ecb = GLUE_FUNC_CAST(serpent_dec_blk_xway) }
    }, {
        .num_blocks = 1,
        .fn_u = { .ecb = GLUE_FUNC_CAST(__serpent_decrypt) }
    } }
};

static const struct common_glue_ctx serpent_dec_cbc = {
    .num_funcs = 2,
    .fpu_blocks_limit = SERPENT_PARALLEL_BLOCKS,

    .funcs = { {
        .num_blocks = SERPENT_PARALLEL_BLOCKS,
        .fn_u = { .cbc = GLUE_CBC_FUNC_CAST(serpent_decrypt_cbc_xway) }
    }, {
        .num_blocks = 1,
        .fn_u = { .cbc = GLUE_CBC_FUNC_CAST(__serpent_decrypt) }
    } }
};

static int ecb_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
               struct scatterlist *src, unsigned int nbytes)
{
    return glue_ecb_crypt_128bit(&serpent_enc, desc, dst, src, nbytes);
}

static int ecb_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
               struct scatterlist *src, unsigned int nbytes)
{
    return glue_ecb_crypt_128bit(&serpent_dec, desc, dst, src, nbytes);
}

static int cbc_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
               struct scatterlist *src, unsigned int nbytes)
{
    return glue_cbc_encrypt_128bit(GLUE_FUNC_CAST(__serpent_encrypt), desc,
                     dst, src, nbytes);
}

static int cbc_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
               struct scatterlist *src, unsigned int nbytes)
{
    return glue_cbc_decrypt_128bit(&serpent_dec_cbc, desc, dst, src,
                       nbytes);
}

static int ctr_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
             struct scatterlist *src, unsigned int nbytes)
{
    return glue_ctr_crypt_128bit(&serpent_ctr, desc, dst, src, nbytes);
}

static inline bool serpent_fpu_begin(bool fpu_enabled, unsigned int nbytes)
{
    return glue_fpu_begin(SERPENT_BLOCK_SIZE, SERPENT_PARALLEL_BLOCKS,
                  NULL, fpu_enabled, nbytes);
}

static inline void serpent_fpu_end(bool fpu_enabled)
{
    glue_fpu_end(fpu_enabled);
}

struct crypt_priv {
    struct serpent_ctx *ctx;
    bool fpu_enabled;
};

static void encrypt_callback(void *priv, u8 *srcdst, unsigned int nbytes)
{
    const unsigned int bsize = SERPENT_BLOCK_SIZE;
    struct crypt_priv *ctx = priv;
    int i;

    ctx->fpu_enabled = serpent_fpu_begin(ctx->fpu_enabled, nbytes);

    if (nbytes == bsize * SERPENT_PARALLEL_BLOCKS) {
        serpent_enc_blk_xway(ctx->ctx, srcdst, srcdst);
        return;
    }

    for (i = 0; i < nbytes / bsize; i++, srcdst += bsize)
        __serpent_encrypt(ctx->ctx, srcdst, srcdst);
}

static void decrypt_callback(void *priv, u8 *srcdst, unsigned int nbytes)
{
    const unsigned int bsize = SERPENT_BLOCK_SIZE;
    struct crypt_priv *ctx = priv;
    int i;

    ctx->fpu_enabled = serpent_fpu_begin(ctx->fpu_enabled, nbytes);

    if (nbytes == bsize * SERPENT_PARALLEL_BLOCKS) {
        serpent_dec_blk_xway(ctx->ctx, srcdst, srcdst);
        return;
    }

    for (i = 0; i < nbytes / bsize; i++, srcdst += bsize)
        __serpent_decrypt(ctx->ctx, srcdst, srcdst);
}

struct serpent_lrw_ctx {
    struct lrw_table_ctx lrw_table;
    struct serpent_ctx serpent_ctx;
};

static int lrw_serpent_setkey(struct crypto_tfm *tfm, const u8 *key,
                  unsigned int keylen)
{
    struct serpent_lrw_ctx *ctx = crypto_tfm_ctx(tfm);
    int err;

    err = __serpent_setkey(&ctx->serpent_ctx, key, keylen -
                            SERPENT_BLOCK_SIZE);
    if (err)
        return err;

    return lrw_init_table(&ctx->lrw_table, key + keylen -
                        SERPENT_BLOCK_SIZE);
}

static int lrw_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
               struct scatterlist *src, unsigned int nbytes)
{
    struct serpent_lrw_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
    be128 buf[SERPENT_PARALLEL_BLOCKS];
    struct crypt_priv crypt_ctx = {
        .ctx = &ctx->serpent_ctx,
        .fpu_enabled = false,
    };
    struct lrw_crypt_req req = {
        .tbuf = buf,
        .tbuflen = sizeof(buf),

        .table_ctx = &ctx->lrw_table,
        .crypt_ctx = &crypt_ctx,
        .crypt_fn = encrypt_callback,
    };
    int ret;

    desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
    ret = lrw_crypt(desc, dst, src, nbytes, &req);
    serpent_fpu_end(crypt_ctx.fpu_enabled);

    return ret;
}

static int lrw_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
               struct scatterlist *src, unsigned int nbytes)
{
    struct serpent_lrw_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
    be128 buf[SERPENT_PARALLEL_BLOCKS];
    struct crypt_priv crypt_ctx = {
        .ctx = &ctx->serpent_ctx,
        .fpu_enabled = false,
    };
    struct lrw_crypt_req req = {
        .tbuf = buf,
        .tbuflen = sizeof(buf),

        .table_ctx = &ctx->lrw_table,
        .crypt_ctx = &crypt_ctx,
        .crypt_fn = decrypt_callback,
    };
    int ret;

    desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
    ret = lrw_crypt(desc, dst, src, nbytes, &req);
    serpent_fpu_end(crypt_ctx.fpu_enabled);

    return ret;
}

static void lrw_exit_tfm(struct crypto_tfm *tfm)
{
    struct serpent_lrw_ctx *ctx = crypto_tfm_ctx(tfm);

    lrw_free_table(&ctx->lrw_table);
}

struct serpent_xts_ctx {
    struct serpent_ctx tweak_ctx;
    struct serpent_ctx crypt_ctx;
};

static int xts_serpent_setkey(struct crypto_tfm *tfm, const u8 *key,
                  unsigned int keylen)
{
    struct serpent_xts_ctx *ctx = crypto_tfm_ctx(tfm);
    u32 *flags = &tfm->crt_flags;
    int err;

    /* key consists of keys of equal size concatenated, therefore
     * the length must be even
     */
    if (keylen % 2) {
        *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
        return -EINVAL;
    }

    /* first half of xts-key is for crypt */
    err = __serpent_setkey(&ctx->crypt_ctx, key, keylen / 2);
    if (err)
        return err;

    /* second half of xts-key is for tweak */
    return __serpent_setkey(&ctx->tweak_ctx, key + keylen / 2, keylen / 2);
}

static int xts_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
               struct scatterlist *src, unsigned int nbytes)
{
    struct serpent_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
    be128 buf[SERPENT_PARALLEL_BLOCKS];
    struct crypt_priv crypt_ctx = {
        .ctx = &ctx->crypt_ctx,
        .fpu_enabled = false,
    };
    struct xts_crypt_req req = {
        .tbuf = buf,
        .tbuflen = sizeof(buf),

        .tweak_ctx = &ctx->tweak_ctx,
        .tweak_fn = XTS_TWEAK_CAST(__serpent_encrypt),
        .crypt_ctx = &crypt_ctx,
        .crypt_fn = encrypt_callback,
    };
    int ret;

    desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
    ret = xts_crypt(desc, dst, src, nbytes, &req);
    serpent_fpu_end(crypt_ctx.fpu_enabled);

    return ret;
}

static int xts_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
               struct scatterlist *src, unsigned int nbytes)
{
    struct serpent_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
    be128 buf[SERPENT_PARALLEL_BLOCKS];
    struct crypt_priv crypt_ctx = {
        .ctx = &ctx->crypt_ctx,
        .fpu_enabled = false,
    };
    struct xts_crypt_req req = {
        .tbuf = buf,
        .tbuflen = sizeof(buf),

        .tweak_ctx = &ctx->tweak_ctx,
        .tweak_fn = XTS_TWEAK_CAST(__serpent_encrypt),
        .crypt_ctx = &crypt_ctx,
        .crypt_fn = decrypt_callback,
    };
    int ret;

    desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
    ret = xts_crypt(desc, dst, src, nbytes, &req);
    serpent_fpu_end(crypt_ctx.fpu_enabled);

    return ret;
}

static struct crypto_alg serpent_algs[10] = { {
    .cra_name       = "__ecb-serpent-avx",
    .cra_driver_name    = "__driver-ecb-serpent-avx",
    .cra_priority       = 0,
    .cra_flags      = CRYPTO_ALG_TYPE_BLKCIPHER,
    .cra_blocksize      = SERPENT_BLOCK_SIZE,
    .cra_ctxsize        = sizeof(struct serpent_ctx),
    .cra_alignmask      = 0,
    .cra_type       = &crypto_blkcipher_type,
    .cra_module     = THIS_MODULE,
    .cra_u = {
        .blkcipher = {
            .min_keysize    = SERPENT_MIN_KEY_SIZE,
            .max_keysize    = SERPENT_MAX_KEY_SIZE,
            .setkey     = serpent_setkey,
            .encrypt    = ecb_encrypt,
            .decrypt    = ecb_decrypt,
        },
    },
}, {
    .cra_name       = "__cbc-serpent-avx",
    .cra_driver_name    = "__driver-cbc-serpent-avx",
    .cra_priority       = 0,
    .cra_flags      = CRYPTO_ALG_TYPE_BLKCIPHER,
    .cra_blocksize      = SERPENT_BLOCK_SIZE,
    .cra_ctxsize        = sizeof(struct serpent_ctx),
    .cra_alignmask      = 0,
    .cra_type       = &crypto_blkcipher_type,
    .cra_module     = THIS_MODULE,
    .cra_u = {
        .blkcipher = {
            .min_keysize    = SERPENT_MIN_KEY_SIZE,
            .max_keysize    = SERPENT_MAX_KEY_SIZE,
            .setkey     = serpent_setkey,
            .encrypt    = cbc_encrypt,
            .decrypt    = cbc_decrypt,
        },
    },
}, {
    .cra_name       = "__ctr-serpent-avx",
    .cra_driver_name    = "__driver-ctr-serpent-avx",
    .cra_priority       = 0,
    .cra_flags      = CRYPTO_ALG_TYPE_BLKCIPHER,
    .cra_blocksize      = 1,
    .cra_ctxsize        = sizeof(struct serpent_ctx),
    .cra_alignmask      = 0,
    .cra_type       = &crypto_blkcipher_type,
    .cra_module     = THIS_MODULE,
    .cra_u = {
        .blkcipher = {
            .min_keysize    = SERPENT_MIN_KEY_SIZE,
            .max_keysize    = SERPENT_MAX_KEY_SIZE,
            .ivsize     = SERPENT_BLOCK_SIZE,
            .setkey     = serpent_setkey,
            .encrypt    = ctr_crypt,
            .decrypt    = ctr_crypt,
        },
    },
}, {
    .cra_name       = "__lrw-serpent-avx",
    .cra_driver_name    = "__driver-lrw-serpent-avx",
    .cra_priority       = 0,
    .cra_flags      = CRYPTO_ALG_TYPE_BLKCIPHER,
    .cra_blocksize      = SERPENT_BLOCK_SIZE,
    .cra_ctxsize        = sizeof(struct serpent_lrw_ctx),
    .cra_alignmask      = 0,
    .cra_type       = &crypto_blkcipher_type,
    .cra_module     = THIS_MODULE,
    .cra_exit       = lrw_exit_tfm,
    .cra_u = {
        .blkcipher = {
            .min_keysize    = SERPENT_MIN_KEY_SIZE +
                      SERPENT_BLOCK_SIZE,
            .max_keysize    = SERPENT_MAX_KEY_SIZE +
                      SERPENT_BLOCK_SIZE,
            .ivsize     = SERPENT_BLOCK_SIZE,
            .setkey     = lrw_serpent_setkey,
            .encrypt    = lrw_encrypt,
            .decrypt    = lrw_decrypt,
        },
    },
}, {
    .cra_name       = "__xts-serpent-avx",
    .cra_driver_name    = "__driver-xts-serpent-avx",
    .cra_priority       = 0,
    .cra_flags      = CRYPTO_ALG_TYPE_BLKCIPHER,
    .cra_blocksize      = SERPENT_BLOCK_SIZE,
    .cra_ctxsize        = sizeof(struct serpent_xts_ctx),
    .cra_alignmask      = 0,
    .cra_type       = &crypto_blkcipher_type,
    .cra_module     = THIS_MODULE,
    .cra_u = {
        .blkcipher = {
            .min_keysize    = SERPENT_MIN_KEY_SIZE * 2,
            .max_keysize    = SERPENT_MAX_KEY_SIZE * 2,
            .ivsize     = SERPENT_BLOCK_SIZE,
            .setkey     = xts_serpent_setkey,
            .encrypt    = xts_encrypt,
            .decrypt    = xts_decrypt,
        },
    },
}, {
    .cra_name       = "ecb(serpent)",
    .cra_driver_name    = "ecb-serpent-avx",
    .cra_priority       = 500,
    .cra_flags      = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
    .cra_blocksize      = SERPENT_BLOCK_SIZE,
    .cra_ctxsize        = sizeof(struct async_helper_ctx),
    .cra_alignmask      = 0,
    .cra_type       = &crypto_ablkcipher_type,
    .cra_module     = THIS_MODULE,
    .cra_init       = ablk_init,
    .cra_exit       = ablk_exit,
    .cra_u = {
        .ablkcipher = {
            .min_keysize    = SERPENT_MIN_KEY_SIZE,
            .max_keysize    = SERPENT_MAX_KEY_SIZE,
            .setkey     = ablk_set_key,
            .encrypt    = ablk_encrypt,
            .decrypt    = ablk_decrypt,
        },
    },
}, {
    .cra_name       = "cbc(serpent)",
    .cra_driver_name    = "cbc-serpent-avx",
    .cra_priority       = 500,
    .cra_flags      = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
    .cra_blocksize      = SERPENT_BLOCK_SIZE,
    .cra_ctxsize        = sizeof(struct async_helper_ctx),
    .cra_alignmask      = 0,
    .cra_type       = &crypto_ablkcipher_type,
    .cra_module     = THIS_MODULE,
    .cra_init       = ablk_init,
    .cra_exit       = ablk_exit,
    .cra_u = {
        .ablkcipher = {
            .min_keysize    = SERPENT_MIN_KEY_SIZE,
            .max_keysize    = SERPENT_MAX_KEY_SIZE,
            .ivsize     = SERPENT_BLOCK_SIZE,
            .setkey     = ablk_set_key,
            .encrypt    = __ablk_encrypt,
            .decrypt    = ablk_decrypt,
        },
    },
}, {
    .cra_name       = "ctr(serpent)",
    .cra_driver_name    = "ctr-serpent-avx",
    .cra_priority       = 500,
    .cra_flags      = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
    .cra_blocksize      = 1,
    .cra_ctxsize        = sizeof(struct async_helper_ctx),
    .cra_alignmask      = 0,
    .cra_type       = &crypto_ablkcipher_type,
    .cra_module     = THIS_MODULE,
    .cra_init       = ablk_init,
    .cra_exit       = ablk_exit,
    .cra_u = {
        .ablkcipher = {
            .min_keysize    = SERPENT_MIN_KEY_SIZE,
            .max_keysize    = SERPENT_MAX_KEY_SIZE,
            .ivsize     = SERPENT_BLOCK_SIZE,
            .setkey     = ablk_set_key,
            .encrypt    = ablk_encrypt,
            .decrypt    = ablk_encrypt,
            .geniv      = "chainiv",
        },
    },
}, {
    .cra_name       = "lrw(serpent)",
    .cra_driver_name    = "lrw-serpent-avx",
    .cra_priority       = 500,
    .cra_flags      = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
    .cra_blocksize      = SERPENT_BLOCK_SIZE,
    .cra_ctxsize        = sizeof(struct async_helper_ctx),
    .cra_alignmask      = 0,
    .cra_type       = &crypto_ablkcipher_type,
    .cra_module     = THIS_MODULE,
    .cra_init       = ablk_init,
    .cra_exit       = ablk_exit,
    .cra_u = {
        .ablkcipher = {
            .min_keysize    = SERPENT_MIN_KEY_SIZE +
                      SERPENT_BLOCK_SIZE,
            .max_keysize    = SERPENT_MAX_KEY_SIZE +
                      SERPENT_BLOCK_SIZE,
            .ivsize     = SERPENT_BLOCK_SIZE,
            .setkey     = ablk_set_key,
            .encrypt    = ablk_encrypt,
            .decrypt    = ablk_decrypt,
        },
    },
}, {
    .cra_name       = "xts(serpent)",
    .cra_driver_name    = "xts-serpent-avx",
    .cra_priority       = 500,
    .cra_flags      = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
    .cra_blocksize      = SERPENT_BLOCK_SIZE,
    .cra_ctxsize        = sizeof(struct async_helper_ctx),
    .cra_alignmask      = 0,
    .cra_type       = &crypto_ablkcipher_type,
    .cra_module     = THIS_MODULE,
    .cra_init       = ablk_init,
    .cra_exit       = ablk_exit,
    .cra_u = {
        .ablkcipher = {
            .min_keysize    = SERPENT_MIN_KEY_SIZE * 2,
            .max_keysize    = SERPENT_MAX_KEY_SIZE * 2,
            .ivsize     = SERPENT_BLOCK_SIZE,
            .setkey     = ablk_set_key,
            .encrypt    = ablk_encrypt,
            .decrypt    = ablk_decrypt,
        },
    },
} };

static int __init serpent_init(void)
{
    u64 xcr0;

    if (!cpu_has_avx || !cpu_has_osxsave) {
        printk(KERN_INFO "AVX instructions are not detected.\n");
        return -ENODEV;
    }

    xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK);
    if ((xcr0 & (XSTATE_SSE | XSTATE_YMM)) != (XSTATE_SSE | XSTATE_YMM)) {
        printk(KERN_INFO "AVX detected but unusable.\n");
        return -ENODEV;
    }

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

static void __exit serpent_exit(void)
{
    crypto_unregister_algs(serpent_algs, ARRAY_SIZE(serpent_algs));
}

module_init(serpent_init);
module_exit(serpent_exit);

MODULE_DESCRIPTION("Serpent Cipher Algorithm, AVX optimized");
MODULE_LICENSE("GPL");
MODULE_ALIAS("serpent");