2016-06-22 16:49:15 +00:00
|
|
|
/* ECDH key-agreement protocol
|
|
|
|
*
|
|
|
|
* Copyright (c) 2016, Intel Corporation
|
|
|
|
* Authors: Salvator Benedetto <salvatore.benedetto@intel.com>
|
|
|
|
*
|
|
|
|
* This program is free software; you can redistribute it and/or
|
|
|
|
* modify it under the terms of the GNU General Public Licence
|
|
|
|
* as published by the Free Software Foundation; either version
|
|
|
|
* 2 of the Licence, or (at your option) any later version.
|
|
|
|
*/
|
|
|
|
|
|
|
|
#include <linux/module.h>
|
|
|
|
#include <crypto/internal/kpp.h>
|
|
|
|
#include <crypto/kpp.h>
|
|
|
|
#include <crypto/ecdh.h>
|
|
|
|
#include <linux/scatterlist.h>
|
|
|
|
#include "ecc.h"
|
|
|
|
|
|
|
|
struct ecdh_ctx {
|
|
|
|
unsigned int curve_id;
|
|
|
|
unsigned int ndigits;
|
|
|
|
u64 private_key[ECC_MAX_DIGITS];
|
|
|
|
u64 public_key[2 * ECC_MAX_DIGITS];
|
|
|
|
u64 shared_secret[ECC_MAX_DIGITS];
|
|
|
|
};
|
|
|
|
|
|
|
|
static inline struct ecdh_ctx *ecdh_get_ctx(struct crypto_kpp *tfm)
|
|
|
|
{
|
|
|
|
return kpp_tfm_ctx(tfm);
|
|
|
|
}
|
|
|
|
|
|
|
|
static unsigned int ecdh_supported_curve(unsigned int curve_id)
|
|
|
|
{
|
|
|
|
switch (curve_id) {
|
|
|
|
case ECC_CURVE_NIST_P192: return 3;
|
|
|
|
case ECC_CURVE_NIST_P256: return 4;
|
|
|
|
default: return 0;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2017-02-24 23:46:58 +00:00
|
|
|
static int ecdh_set_secret(struct crypto_kpp *tfm, const void *buf,
|
|
|
|
unsigned int len)
|
2016-06-22 16:49:15 +00:00
|
|
|
{
|
|
|
|
struct ecdh_ctx *ctx = ecdh_get_ctx(tfm);
|
|
|
|
struct ecdh params;
|
|
|
|
unsigned int ndigits;
|
|
|
|
|
|
|
|
if (crypto_ecdh_decode_key(buf, len, ¶ms) < 0)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
ndigits = ecdh_supported_curve(params.curve_id);
|
|
|
|
if (!ndigits)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
ctx->curve_id = params.curve_id;
|
|
|
|
ctx->ndigits = ndigits;
|
|
|
|
|
|
|
|
if (ecc_is_key_valid(ctx->curve_id, ctx->ndigits,
|
|
|
|
(const u8 *)params.key, params.key_size) < 0)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
memcpy(ctx->private_key, params.key, params.key_size);
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int ecdh_compute_value(struct kpp_request *req)
|
|
|
|
{
|
|
|
|
int ret = 0;
|
|
|
|
struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
|
|
|
|
struct ecdh_ctx *ctx = ecdh_get_ctx(tfm);
|
|
|
|
size_t copied, nbytes;
|
|
|
|
void *buf;
|
|
|
|
|
|
|
|
nbytes = ctx->ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
|
|
|
|
|
|
|
|
if (req->src) {
|
|
|
|
copied = sg_copy_to_buffer(req->src, 1, ctx->public_key,
|
|
|
|
2 * nbytes);
|
|
|
|
if (copied != 2 * nbytes)
|
|
|
|
return -EINVAL;
|
|
|
|
|
2016-06-24 06:20:22 +00:00
|
|
|
ret = crypto_ecdh_shared_secret(ctx->curve_id, ctx->ndigits,
|
2016-06-22 16:49:15 +00:00
|
|
|
(const u8 *)ctx->private_key, nbytes,
|
|
|
|
(const u8 *)ctx->public_key, 2 * nbytes,
|
|
|
|
(u8 *)ctx->shared_secret, nbytes);
|
|
|
|
|
|
|
|
buf = ctx->shared_secret;
|
|
|
|
} else {
|
|
|
|
ret = ecdh_make_pub_key(ctx->curve_id, ctx->ndigits,
|
|
|
|
(const u8 *)ctx->private_key, nbytes,
|
|
|
|
(u8 *)ctx->public_key,
|
|
|
|
sizeof(ctx->public_key));
|
|
|
|
buf = ctx->public_key;
|
|
|
|
/* Public part is a point thus it has both coordinates */
|
|
|
|
nbytes *= 2;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (ret < 0)
|
|
|
|
return ret;
|
|
|
|
|
|
|
|
copied = sg_copy_from_buffer(req->dst, 1, buf, nbytes);
|
|
|
|
if (copied != nbytes)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int ecdh_max_size(struct crypto_kpp *tfm)
|
|
|
|
{
|
|
|
|
struct ecdh_ctx *ctx = ecdh_get_ctx(tfm);
|
|
|
|
int nbytes = ctx->ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
|
|
|
|
|
|
|
|
/* Public key is made of two coordinates */
|
|
|
|
return 2 * nbytes;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void no_exit_tfm(struct crypto_kpp *tfm)
|
|
|
|
{
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
static struct kpp_alg ecdh = {
|
|
|
|
.set_secret = ecdh_set_secret,
|
|
|
|
.generate_public_key = ecdh_compute_value,
|
|
|
|
.compute_shared_secret = ecdh_compute_value,
|
|
|
|
.max_size = ecdh_max_size,
|
|
|
|
.exit = no_exit_tfm,
|
|
|
|
.base = {
|
|
|
|
.cra_name = "ecdh",
|
|
|
|
.cra_driver_name = "ecdh-generic",
|
|
|
|
.cra_priority = 100,
|
|
|
|
.cra_module = THIS_MODULE,
|
|
|
|
.cra_ctxsize = sizeof(struct ecdh_ctx),
|
|
|
|
},
|
|
|
|
};
|
|
|
|
|
|
|
|
static int ecdh_init(void)
|
|
|
|
{
|
|
|
|
return crypto_register_kpp(&ecdh);
|
|
|
|
}
|
|
|
|
|
|
|
|
static void ecdh_exit(void)
|
|
|
|
{
|
|
|
|
crypto_unregister_kpp(&ecdh);
|
|
|
|
}
|
|
|
|
|
|
|
|
module_init(ecdh_init);
|
|
|
|
module_exit(ecdh_exit);
|
|
|
|
MODULE_ALIAS_CRYPTO("ecdh");
|
|
|
|
MODULE_LICENSE("GPL");
|
|
|
|
MODULE_DESCRIPTION("ECDH generic algorithm");
|