// SPDX-License-Identifier: GPL-2.0+
/*
 * Cryptographic API.
 *
 * s390 implementation of the DES Cipher Algorithm.
 *
 * Copyright IBM Corp. 2003, 2011
 * Author(s): Thomas Spatzier
 *            Jan Glauber (jan.glauber@de.ibm.com)
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/cpufeature.h>
#include <linux/crypto.h>
#include <linux/fips.h>
#include <linux/mutex.h>
#include <crypto/algapi.h>
#include <crypto/internal/des.h>
#include <crypto/internal/skcipher.h>
#include <asm/cpacf.h>

#define DES3_KEY_SIZE   (3 * DES_KEY_SIZE)

static u8 *ctrblk;
static DEFINE_MUTEX(ctrblk_lock);

static cpacf_mask_t km_functions, kmc_functions, kmctr_functions;

struct s390_des_ctx {
        u8 iv[DES_BLOCK_SIZE];
        u8 key[DES3_KEY_SIZE];
};

static int des_setkey(struct crypto_tfm *tfm, const u8 *key,
                      unsigned int key_len)
{
        struct s390_des_ctx *ctx = crypto_tfm_ctx(tfm);
        int err;

        err = crypto_des_verify_key(tfm, key);
        if (err)
                return err;

        memcpy(ctx->key, key, key_len);
        return 0;
}

static int des_setkey_skcipher(struct crypto_skcipher *tfm, const u8 *key,
                               unsigned int key_len)
{
        return des_setkey(crypto_skcipher_tfm(tfm), key, key_len);
}

static void s390_des_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
        struct s390_des_ctx *ctx = crypto_tfm_ctx(tfm);

        cpacf_km(CPACF_KM_DEA, ctx->key, out, in, DES_BLOCK_SIZE);
}

static void s390_des_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
        struct s390_des_ctx *ctx = crypto_tfm_ctx(tfm);

        cpacf_km(CPACF_KM_DEA | CPACF_DECRYPT,
                 ctx->key, out, in, DES_BLOCK_SIZE);
}

static struct crypto_alg des_alg = {
        .cra_name               =       "des",
        .cra_driver_name        =       "des-s390",
        .cra_priority           =       300,
        .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
        .cra_blocksize          =       DES_BLOCK_SIZE,
        .cra_ctxsize            =       sizeof(struct s390_des_ctx),
        .cra_module             =       THIS_MODULE,
        .cra_u                  =       {
                .cipher = {
                        .cia_min_keysize        =       DES_KEY_SIZE,
                        .cia_max_keysize        =       DES_KEY_SIZE,
                        .cia_setkey             =       des_setkey,
                        .cia_encrypt            =       s390_des_encrypt,
                        .cia_decrypt            =       s390_des_decrypt,
                }
        }
};

static int ecb_desall_crypt(struct skcipher_request *req, unsigned long fc)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
        struct s390_des_ctx *ctx = crypto_skcipher_ctx(tfm);
        struct skcipher_walk walk;
        unsigned int nbytes, n;
        int ret;

        ret = skcipher_walk_virt(&walk, req, false);
        while ((nbytes = walk.nbytes) != 0) {
                /* only use complete blocks */
                n = nbytes & ~(DES_BLOCK_SIZE - 1);
                cpacf_km(fc, ctx->key, walk.dst.virt.addr,
                         walk.src.virt.addr, n);
                ret = skcipher_walk_done(&walk, nbytes - n);
        }
        return ret;
}

static int cbc_desall_crypt(struct skcipher_request *req, unsigned long fc)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
        struct s390_des_ctx *ctx = crypto_skcipher_ctx(tfm);
        struct skcipher_walk walk;
        unsigned int nbytes, n;
        int ret;
        struct {
                u8 iv[DES_BLOCK_SIZE];
                u8 key[DES3_KEY_SIZE];
        } param;

        ret = skcipher_walk_virt(&walk, req, false);
        if (ret)
                return ret;
        memcpy(param.iv, walk.iv, DES_BLOCK_SIZE);
        memcpy(param.key, ctx->key, DES3_KEY_SIZE);
        while ((nbytes = walk.nbytes) != 0) {
                /* only use complete blocks */
                n = nbytes & ~(DES_BLOCK_SIZE - 1);
                cpacf_kmc(fc, &param, walk.dst.virt.addr,
                          walk.src.virt.addr, n);
                memcpy(walk.iv, param.iv, DES_BLOCK_SIZE);
                ret = skcipher_walk_done(&walk, nbytes - n);
        }
        return ret;
}

static int ecb_des_encrypt(struct skcipher_request *req)
{
        return ecb_desall_crypt(req, CPACF_KM_DEA);
}

static int ecb_des_decrypt(struct skcipher_request *req)
{
        return ecb_desall_crypt(req, CPACF_KM_DEA | CPACF_DECRYPT);
}

static struct skcipher_alg ecb_des_alg = {
        .base.cra_name          =       "ecb(des)",
        .base.cra_driver_name   =       "ecb-des-s390",
        .base.cra_priority      =       400,    /* combo: des + ecb */
        .base.cra_blocksize     =       DES_BLOCK_SIZE,
        .base.cra_ctxsize       =       sizeof(struct s390_des_ctx),
        .base.cra_module        =       THIS_MODULE,
        .min_keysize            =       DES_KEY_SIZE,
        .max_keysize            =       DES_KEY_SIZE,
        .setkey                 =       des_setkey_skcipher,
        .encrypt                =       ecb_des_encrypt,
        .decrypt                =       ecb_des_decrypt,
};

static int cbc_des_encrypt(struct skcipher_request *req)
{
        return cbc_desall_crypt(req, CPACF_KMC_DEA);
}

static int cbc_des_decrypt(struct skcipher_request *req)
{
        return cbc_desall_crypt(req, CPACF_KMC_DEA | CPACF_DECRYPT);
}

static struct skcipher_alg cbc_des_alg = {
        .base.cra_name          =       "cbc(des)",
        .base.cra_driver_name   =       "cbc-des-s390",
        .base.cra_priority      =       400,    /* combo: des + cbc */
        .base.cra_blocksize     =       DES_BLOCK_SIZE,
        .base.cra_ctxsize       =       sizeof(struct s390_des_ctx),
        .base.cra_module        =       THIS_MODULE,
        .min_keysize            =       DES_KEY_SIZE,
        .max_keysize            =       DES_KEY_SIZE,
        .ivsize                 =       DES_BLOCK_SIZE,
        .setkey                 =       des_setkey_skcipher,
        .encrypt                =       cbc_des_encrypt,
        .decrypt                =       cbc_des_decrypt,
};

/*
 * RFC2451:
 *
 *   For DES-EDE3, there is no known need to reject weak or
 *   complementation keys.  Any weakness is obviated by the use of
 *   multiple keys.
 *
 *   However, if the first two or last two independent 64-bit keys are
 *   equal (k1 == k2 or k2 == k3), then the DES3 operation is simply the
 *   same as DES.  Implementers MUST reject keys that exhibit this
 *   property.
 *
 *   In fips mode additionally check for all 3 keys are unique.
 *
 */
static int des3_setkey(struct crypto_tfm *tfm, const u8 *key,
                       unsigned int key_len)
{
        struct s390_des_ctx *ctx = crypto_tfm_ctx(tfm);
        int err;

        err = crypto_des3_ede_verify_key(tfm, key);
        if (err)
                return err;

        memcpy(ctx->key, key, key_len);
        return 0;
}

static int des3_setkey_skcipher(struct crypto_skcipher *tfm, const u8 *key,
                                unsigned int key_len)
{
        return des3_setkey(crypto_skcipher_tfm(tfm), key, key_len);
}

static void des3_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
        struct s390_des_ctx *ctx = crypto_tfm_ctx(tfm);

        cpacf_km(CPACF_KM_TDEA_192, ctx->key, dst, src, DES_BLOCK_SIZE);
}

static void des3_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
        struct s390_des_ctx *ctx = crypto_tfm_ctx(tfm);

        cpacf_km(CPACF_KM_TDEA_192 | CPACF_DECRYPT,
                 ctx->key, dst, src, DES_BLOCK_SIZE);
}

static struct crypto_alg des3_alg = {
        .cra_name               =       "des3_ede",
        .cra_driver_name        =       "des3_ede-s390",
        .cra_priority           =       300,
        .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
        .cra_blocksize          =       DES_BLOCK_SIZE,
        .cra_ctxsize            =       sizeof(struct s390_des_ctx),
        .cra_module             =       THIS_MODULE,
        .cra_u                  =       {
                .cipher = {
                        .cia_min_keysize        =       DES3_KEY_SIZE,
                        .cia_max_keysize        =       DES3_KEY_SIZE,
                        .cia_setkey             =       des3_setkey,
                        .cia_encrypt            =       des3_encrypt,
                        .cia_decrypt            =       des3_decrypt,
                }
        }
};

static int ecb_des3_encrypt(struct skcipher_request *req)
{
        return ecb_desall_crypt(req, CPACF_KM_TDEA_192);
}

static int ecb_des3_decrypt(struct skcipher_request *req)
{
        return ecb_desall_crypt(req, CPACF_KM_TDEA_192 | CPACF_DECRYPT);
}

static struct skcipher_alg ecb_des3_alg = {
        .base.cra_name          =       "ecb(des3_ede)",
        .base.cra_driver_name   =       "ecb-des3_ede-s390",
        .base.cra_priority      =       400,    /* combo: des3 + ecb */
        .base.cra_blocksize     =       DES_BLOCK_SIZE,
        .base.cra_ctxsize       =       sizeof(struct s390_des_ctx),
        .base.cra_module        =       THIS_MODULE,
        .min_keysize            =       DES3_KEY_SIZE,
        .max_keysize            =       DES3_KEY_SIZE,
        .setkey                 =       des3_setkey_skcipher,
        .encrypt                =       ecb_des3_encrypt,
        .decrypt                =       ecb_des3_decrypt,
};

static int cbc_des3_encrypt(struct skcipher_request *req)
{
        return cbc_desall_crypt(req, CPACF_KMC_TDEA_192);
}

static int cbc_des3_decrypt(struct skcipher_request *req)
{
        return cbc_desall_crypt(req, CPACF_KMC_TDEA_192 | CPACF_DECRYPT);
}

static struct skcipher_alg cbc_des3_alg = {
        .base.cra_name          =       "cbc(des3_ede)",
        .base.cra_driver_name   =       "cbc-des3_ede-s390",
        .base.cra_priority      =       400,    /* combo: des3 + cbc */
        .base.cra_blocksize     =       DES_BLOCK_SIZE,
        .base.cra_ctxsize       =       sizeof(struct s390_des_ctx),
        .base.cra_module        =       THIS_MODULE,
        .min_keysize            =       DES3_KEY_SIZE,
        .max_keysize            =       DES3_KEY_SIZE,
        .ivsize                 =       DES_BLOCK_SIZE,
        .setkey                 =       des3_setkey_skcipher,
        .encrypt                =       cbc_des3_encrypt,
        .decrypt                =       cbc_des3_decrypt,
};

static unsigned int __ctrblk_init(u8 *ctrptr, u8 *iv, unsigned int nbytes)
{
        unsigned int i, n;

        /* align to block size, max. PAGE_SIZE */
        n = (nbytes > PAGE_SIZE) ? PAGE_SIZE : nbytes & ~(DES_BLOCK_SIZE - 1);
        memcpy(ctrptr, iv, DES_BLOCK_SIZE);
        for (i = (n / DES_BLOCK_SIZE) - 1; i > 0; i--) {
                memcpy(ctrptr + DES_BLOCK_SIZE, ctrptr, DES_BLOCK_SIZE);
                crypto_inc(ctrptr + DES_BLOCK_SIZE, DES_BLOCK_SIZE);
                ctrptr += DES_BLOCK_SIZE;
        }
        return n;
}

static int ctr_desall_crypt(struct skcipher_request *req, unsigned long fc)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
        struct s390_des_ctx *ctx = crypto_skcipher_ctx(tfm);
        u8 buf[DES_BLOCK_SIZE], *ctrptr;
        struct skcipher_walk walk;
        unsigned int n, nbytes;
        int ret, locked;

        locked = mutex_trylock(&ctrblk_lock);

        ret = skcipher_walk_virt(&walk, req, false);
        while ((nbytes = walk.nbytes) >= DES_BLOCK_SIZE) {
                n = DES_BLOCK_SIZE;
                if (nbytes >= 2*DES_BLOCK_SIZE && locked)
                        n = __ctrblk_init(ctrblk, walk.iv, nbytes);
                ctrptr = (n > DES_BLOCK_SIZE) ? ctrblk : walk.iv;
                cpacf_kmctr(fc, ctx->key, walk.dst.virt.addr,
                            walk.src.virt.addr, n, ctrptr);
                if (ctrptr == ctrblk)
                        memcpy(walk.iv, ctrptr + n - DES_BLOCK_SIZE,
                                DES_BLOCK_SIZE);
                crypto_inc(walk.iv, DES_BLOCK_SIZE);
                ret = skcipher_walk_done(&walk, nbytes - n);
        }
        if (locked)
                mutex_unlock(&ctrblk_lock);
        /* final block may be < DES_BLOCK_SIZE, copy only nbytes */
        if (nbytes) {
                cpacf_kmctr(fc, ctx->key, buf, walk.src.virt.addr,
                            DES_BLOCK_SIZE, walk.iv);
                memcpy(walk.dst.virt.addr, buf, nbytes);
                crypto_inc(walk.iv, DES_BLOCK_SIZE);
                ret = skcipher_walk_done(&walk, 0);
        }
        return ret;
}

static int ctr_des_crypt(struct skcipher_request *req)
{
        return ctr_desall_crypt(req, CPACF_KMCTR_DEA);
}

static struct skcipher_alg ctr_des_alg = {
        .base.cra_name          =       "ctr(des)",
        .base.cra_driver_name   =       "ctr-des-s390",
        .base.cra_priority      =       400,    /* combo: des + ctr */
        .base.cra_blocksize     =       1,
        .base.cra_ctxsize       =       sizeof(struct s390_des_ctx),
        .base.cra_module        =       THIS_MODULE,
        .min_keysize            =       DES_KEY_SIZE,
        .max_keysize            =       DES_KEY_SIZE,
        .ivsize                 =       DES_BLOCK_SIZE,
        .setkey                 =       des_setkey_skcipher,
        .encrypt                =       ctr_des_crypt,
        .decrypt                =       ctr_des_crypt,
        .chunksize              =       DES_BLOCK_SIZE,
};

static int ctr_des3_crypt(struct skcipher_request *req)
{
        return ctr_desall_crypt(req, CPACF_KMCTR_TDEA_192);
}

static struct skcipher_alg ctr_des3_alg = {
        .base.cra_name          =       "ctr(des3_ede)",
        .base.cra_driver_name   =       "ctr-des3_ede-s390",
        .base.cra_priority      =       400,    /* combo: des3 + ede */
        .base.cra_blocksize     =       1,
        .base.cra_ctxsize       =       sizeof(struct s390_des_ctx),
        .base.cra_module        =       THIS_MODULE,
        .min_keysize            =       DES3_KEY_SIZE,
        .max_keysize            =       DES3_KEY_SIZE,
        .ivsize                 =       DES_BLOCK_SIZE,
        .setkey                 =       des3_setkey_skcipher,
        .encrypt                =       ctr_des3_crypt,
        .decrypt                =       ctr_des3_crypt,
        .chunksize              =       DES_BLOCK_SIZE,
};

static struct crypto_alg *des_s390_algs_ptr[2];
static int des_s390_algs_num;
static struct skcipher_alg *des_s390_skciphers_ptr[6];
static int des_s390_skciphers_num;

static int des_s390_register_alg(struct crypto_alg *alg)
{
        int ret;

        ret = crypto_register_alg(alg);
        if (!ret)
                des_s390_algs_ptr[des_s390_algs_num++] = alg;
        return ret;
}

static int des_s390_register_skcipher(struct skcipher_alg *alg)
{
        int ret;

        ret = crypto_register_skcipher(alg);
        if (!ret)
                des_s390_skciphers_ptr[des_s390_skciphers_num++] = alg;
        return ret;
}

static void des_s390_exit(void)
{
        while (des_s390_algs_num--)
                crypto_unregister_alg(des_s390_algs_ptr[des_s390_algs_num]);
        while (des_s390_skciphers_num--)
                crypto_unregister_skcipher(des_s390_skciphers_ptr[des_s390_skciphers_num]);
        if (ctrblk)
                free_page((unsigned long) ctrblk);
}

static int __init des_s390_init(void)
{
        int ret;

        /* Query available functions for KM, KMC and KMCTR */
        cpacf_query(CPACF_KM, &km_functions);
        cpacf_query(CPACF_KMC, &kmc_functions);
        cpacf_query(CPACF_KMCTR, &kmctr_functions);

        if (cpacf_test_func(&km_functions, CPACF_KM_DEA)) {
                ret = des_s390_register_alg(&des_alg);
                if (ret)
                        goto out_err;
                ret = des_s390_register_skcipher(&ecb_des_alg);
                if (ret)
                        goto out_err;
        }
        if (cpacf_test_func(&kmc_functions, CPACF_KMC_DEA)) {
                ret = des_s390_register_skcipher(&cbc_des_alg);
                if (ret)
                        goto out_err;
        }
        if (cpacf_test_func(&km_functions, CPACF_KM_TDEA_192)) {
                ret = des_s390_register_alg(&des3_alg);
                if (ret)
                        goto out_err;
                ret = des_s390_register_skcipher(&ecb_des3_alg);
                if (ret)
                        goto out_err;
        }
        if (cpacf_test_func(&kmc_functions, CPACF_KMC_TDEA_192)) {
                ret = des_s390_register_skcipher(&cbc_des3_alg);
                if (ret)
                        goto out_err;
        }

        if (cpacf_test_func(&kmctr_functions, CPACF_KMCTR_DEA) ||
            cpacf_test_func(&kmctr_functions, CPACF_KMCTR_TDEA_192)) {
                ctrblk = (u8 *) __get_free_page(GFP_KERNEL);
                if (!ctrblk) {
                        ret = -ENOMEM;
                        goto out_err;
                }
        }

        if (cpacf_test_func(&kmctr_functions, CPACF_KMCTR_DEA)) {
                ret = des_s390_register_skcipher(&ctr_des_alg);
                if (ret)
                        goto out_err;
        }
        if (cpacf_test_func(&kmctr_functions, CPACF_KMCTR_TDEA_192)) {
                ret = des_s390_register_skcipher(&ctr_des3_alg);
                if (ret)
                        goto out_err;
        }

        return 0;
out_err:
        des_s390_exit();
        return ret;
}

module_cpu_feature_match(S390_CPU_FEATURE_MSA, des_s390_init);
module_exit(des_s390_exit);

MODULE_ALIAS_CRYPTO("des");
MODULE_ALIAS_CRYPTO("des3_ede");

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("DES & Triple DES EDE Cipher Algorithms");