root/arch/arm64/crypto/sm4-neon-glue.c
/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * SM4 Cipher Algorithm, using ARMv8 NEON
 * as specified in
 * https://tools.ietf.org/id/draft-ribose-cfrg-sm4-10.html
 *
 * Copyright (C) 2022, Alibaba Group.
 * Copyright (C) 2022 Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
 */

#include <linux/module.h>
#include <linux/crypto.h>
#include <linux/kernel.h>
#include <linux/cpufeature.h>
#include <asm/neon.h>
#include <asm/simd.h>
#include <crypto/internal/simd.h>
#include <crypto/internal/skcipher.h>
#include <crypto/sm4.h>

asmlinkage void sm4_neon_crypt(const u32 *rkey, u8 *dst, const u8 *src,
                               unsigned int nblocks);
asmlinkage void sm4_neon_cbc_dec(const u32 *rkey_dec, u8 *dst, const u8 *src,
                                 u8 *iv, unsigned int nblocks);
asmlinkage void sm4_neon_ctr_crypt(const u32 *rkey_enc, u8 *dst, const u8 *src,
                                   u8 *iv, unsigned int nblocks);

static int sm4_setkey(struct crypto_skcipher *tfm, const u8 *key,
                      unsigned int key_len)
{
        struct sm4_ctx *ctx = crypto_skcipher_ctx(tfm);

        return sm4_expandkey(ctx, key, key_len);
}

static int sm4_ecb_do_crypt(struct skcipher_request *req, const u32 *rkey)
{
        struct skcipher_walk walk;
        unsigned int nbytes;
        int err;

        err = skcipher_walk_virt(&walk, req, false);

        while ((nbytes = walk.nbytes) > 0) {
                const u8 *src = walk.src.virt.addr;
                u8 *dst = walk.dst.virt.addr;
                unsigned int nblocks;

                nblocks = nbytes / SM4_BLOCK_SIZE;
                if (nblocks) {
                        scoped_ksimd()
                                sm4_neon_crypt(rkey, dst, src, nblocks);
                }

                err = skcipher_walk_done(&walk, nbytes % SM4_BLOCK_SIZE);
        }

        return err;
}

static int sm4_ecb_encrypt(struct skcipher_request *req)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
        struct sm4_ctx *ctx = crypto_skcipher_ctx(tfm);

        return sm4_ecb_do_crypt(req, ctx->rkey_enc);
}

static int sm4_ecb_decrypt(struct skcipher_request *req)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
        struct sm4_ctx *ctx = crypto_skcipher_ctx(tfm);

        return sm4_ecb_do_crypt(req, ctx->rkey_dec);
}

static int sm4_cbc_encrypt(struct skcipher_request *req)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
        struct sm4_ctx *ctx = crypto_skcipher_ctx(tfm);
        struct skcipher_walk walk;
        unsigned int nbytes;
        int err;

        err = skcipher_walk_virt(&walk, req, false);

        while ((nbytes = walk.nbytes) > 0) {
                const u8 *iv = walk.iv;
                const u8 *src = walk.src.virt.addr;
                u8 *dst = walk.dst.virt.addr;

                while (nbytes >= SM4_BLOCK_SIZE) {
                        crypto_xor_cpy(dst, src, iv, SM4_BLOCK_SIZE);
                        sm4_crypt_block(ctx->rkey_enc, dst, dst);
                        iv = dst;
                        src += SM4_BLOCK_SIZE;
                        dst += SM4_BLOCK_SIZE;
                        nbytes -= SM4_BLOCK_SIZE;
                }
                if (iv != walk.iv)
                        memcpy(walk.iv, iv, SM4_BLOCK_SIZE);

                err = skcipher_walk_done(&walk, nbytes);
        }

        return err;
}

static int sm4_cbc_decrypt(struct skcipher_request *req)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
        struct sm4_ctx *ctx = crypto_skcipher_ctx(tfm);
        struct skcipher_walk walk;
        unsigned int nbytes;
        int err;

        err = skcipher_walk_virt(&walk, req, false);

        while ((nbytes = walk.nbytes) > 0) {
                const u8 *src = walk.src.virt.addr;
                u8 *dst = walk.dst.virt.addr;
                unsigned int nblocks;

                nblocks = nbytes / SM4_BLOCK_SIZE;
                if (nblocks) {
                        scoped_ksimd()
                                sm4_neon_cbc_dec(ctx->rkey_dec, dst, src,
                                                 walk.iv, nblocks);
                }

                err = skcipher_walk_done(&walk, nbytes % SM4_BLOCK_SIZE);
        }

        return err;
}

static int sm4_ctr_crypt(struct skcipher_request *req)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
        struct sm4_ctx *ctx = crypto_skcipher_ctx(tfm);
        struct skcipher_walk walk;
        unsigned int nbytes;
        int err;

        err = skcipher_walk_virt(&walk, req, false);

        while ((nbytes = walk.nbytes) > 0) {
                const u8 *src = walk.src.virt.addr;
                u8 *dst = walk.dst.virt.addr;
                unsigned int nblocks;

                nblocks = nbytes / SM4_BLOCK_SIZE;
                if (nblocks) {
                        scoped_ksimd()
                                sm4_neon_ctr_crypt(ctx->rkey_enc, dst, src,
                                                   walk.iv, nblocks);

                        dst += nblocks * SM4_BLOCK_SIZE;
                        src += nblocks * SM4_BLOCK_SIZE;
                        nbytes -= nblocks * SM4_BLOCK_SIZE;
                }

                /* tail */
                if (walk.nbytes == walk.total && nbytes > 0) {
                        u8 keystream[SM4_BLOCK_SIZE];

                        sm4_crypt_block(ctx->rkey_enc, keystream, walk.iv);
                        crypto_inc(walk.iv, SM4_BLOCK_SIZE);
                        crypto_xor_cpy(dst, src, keystream, nbytes);
                        nbytes = 0;
                }

                err = skcipher_walk_done(&walk, nbytes);
        }

        return err;
}

static struct skcipher_alg sm4_algs[] = {
        {
                .base = {
                        .cra_name               = "ecb(sm4)",
                        .cra_driver_name        = "ecb-sm4-neon",
                        .cra_priority           = 200,
                        .cra_blocksize          = SM4_BLOCK_SIZE,
                        .cra_ctxsize            = sizeof(struct sm4_ctx),
                        .cra_module             = THIS_MODULE,
                },
                .min_keysize    = SM4_KEY_SIZE,
                .max_keysize    = SM4_KEY_SIZE,
                .setkey         = sm4_setkey,
                .encrypt        = sm4_ecb_encrypt,
                .decrypt        = sm4_ecb_decrypt,
        }, {
                .base = {
                        .cra_name               = "cbc(sm4)",
                        .cra_driver_name        = "cbc-sm4-neon",
                        .cra_priority           = 200,
                        .cra_blocksize          = SM4_BLOCK_SIZE,
                        .cra_ctxsize            = sizeof(struct sm4_ctx),
                        .cra_module             = THIS_MODULE,
                },
                .min_keysize    = SM4_KEY_SIZE,
                .max_keysize    = SM4_KEY_SIZE,
                .ivsize         = SM4_BLOCK_SIZE,
                .setkey         = sm4_setkey,
                .encrypt        = sm4_cbc_encrypt,
                .decrypt        = sm4_cbc_decrypt,
        }, {
                .base = {
                        .cra_name               = "ctr(sm4)",
                        .cra_driver_name        = "ctr-sm4-neon",
                        .cra_priority           = 200,
                        .cra_blocksize          = 1,
                        .cra_ctxsize            = sizeof(struct sm4_ctx),
                        .cra_module             = THIS_MODULE,
                },
                .min_keysize    = SM4_KEY_SIZE,
                .max_keysize    = SM4_KEY_SIZE,
                .ivsize         = SM4_BLOCK_SIZE,
                .chunksize      = SM4_BLOCK_SIZE,
                .setkey         = sm4_setkey,
                .encrypt        = sm4_ctr_crypt,
                .decrypt        = sm4_ctr_crypt,
        }
};

static int __init sm4_init(void)
{
        return crypto_register_skciphers(sm4_algs, ARRAY_SIZE(sm4_algs));
}

static void __exit sm4_exit(void)
{
        crypto_unregister_skciphers(sm4_algs, ARRAY_SIZE(sm4_algs));
}

module_init(sm4_init);
module_exit(sm4_exit);

MODULE_DESCRIPTION("SM4 ECB/CBC/CTR using ARMv8 NEON");
MODULE_ALIAS_CRYPTO("sm4-neon");
MODULE_ALIAS_CRYPTO("sm4");
MODULE_ALIAS_CRYPTO("ecb(sm4)");
MODULE_ALIAS_CRYPTO("cbc(sm4)");
MODULE_ALIAS_CRYPTO("ctr(sm4)");
MODULE_AUTHOR("Tianjia Zhang <tianjia.zhang@linux.alibaba.com>");
MODULE_LICENSE("GPL v2");