linux/drivers/crypto/atmel-ecc.c
Rob Herring b0cc7491c9 crypto: drivers - Explicitly include correct DT includes
The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.

Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-08-23 11:04:23 +08:00

416 lines
10 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Microchip / Atmel ECC (I2C) driver.
*
* Copyright (c) 2017, Microchip Technology Inc.
* Author: Tudor Ambarus
*/
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <crypto/internal/kpp.h>
#include <crypto/ecdh.h>
#include <crypto/kpp.h>
#include "atmel-i2c.h"
static struct atmel_ecc_driver_data driver_data;
/**
* struct atmel_ecdh_ctx - transformation context
* @client : pointer to i2c client device
* @fallback : used for unsupported curves or when user wants to use its own
* private key.
* @public_key : generated when calling set_secret(). It's the responsibility
* of the user to not call set_secret() while
* generate_public_key() or compute_shared_secret() are in flight.
* @curve_id : elliptic curve id
* @do_fallback: true when the device doesn't support the curve or when the user
* wants to use its own private key.
*/
struct atmel_ecdh_ctx {
struct i2c_client *client;
struct crypto_kpp *fallback;
const u8 *public_key;
unsigned int curve_id;
bool do_fallback;
};
static void atmel_ecdh_done(struct atmel_i2c_work_data *work_data, void *areq,
int status)
{
struct kpp_request *req = areq;
struct atmel_i2c_cmd *cmd = &work_data->cmd;
size_t copied, n_sz;
if (status)
goto free_work_data;
/* might want less than we've got */
n_sz = min_t(size_t, ATMEL_ECC_NIST_P256_N_SIZE, req->dst_len);
/* copy the shared secret */
copied = sg_copy_from_buffer(req->dst, sg_nents_for_len(req->dst, n_sz),
&cmd->data[RSP_DATA_IDX], n_sz);
if (copied != n_sz)
status = -EINVAL;
/* fall through */
free_work_data:
kfree_sensitive(work_data);
kpp_request_complete(req, status);
}
/*
* A random private key is generated and stored in the device. The device
* returns the pair public key.
*/
static int atmel_ecdh_set_secret(struct crypto_kpp *tfm, const void *buf,
unsigned int len)
{
struct atmel_ecdh_ctx *ctx = kpp_tfm_ctx(tfm);
struct atmel_i2c_cmd *cmd;
void *public_key;
struct ecdh params;
int ret = -ENOMEM;
/* free the old public key, if any */
kfree(ctx->public_key);
/* make sure you don't free the old public key twice */
ctx->public_key = NULL;
if (crypto_ecdh_decode_key(buf, len, &params) < 0) {
dev_err(&ctx->client->dev, "crypto_ecdh_decode_key failed\n");
return -EINVAL;
}
if (params.key_size) {
/* fallback to ecdh software implementation */
ctx->do_fallback = true;
return crypto_kpp_set_secret(ctx->fallback, buf, len);
}
cmd = kmalloc(sizeof(*cmd), GFP_KERNEL);
if (!cmd)
return -ENOMEM;
/*
* The device only supports NIST P256 ECC keys. The public key size will
* always be the same. Use a macro for the key size to avoid unnecessary
* computations.
*/
public_key = kmalloc(ATMEL_ECC_PUBKEY_SIZE, GFP_KERNEL);
if (!public_key)
goto free_cmd;
ctx->do_fallback = false;
atmel_i2c_init_genkey_cmd(cmd, DATA_SLOT_2);
ret = atmel_i2c_send_receive(ctx->client, cmd);
if (ret)
goto free_public_key;
/* save the public key */
memcpy(public_key, &cmd->data[RSP_DATA_IDX], ATMEL_ECC_PUBKEY_SIZE);
ctx->public_key = public_key;
kfree(cmd);
return 0;
free_public_key:
kfree(public_key);
free_cmd:
kfree(cmd);
return ret;
}
static int atmel_ecdh_generate_public_key(struct kpp_request *req)
{
struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
struct atmel_ecdh_ctx *ctx = kpp_tfm_ctx(tfm);
size_t copied, nbytes;
int ret = 0;
if (ctx->do_fallback) {
kpp_request_set_tfm(req, ctx->fallback);
return crypto_kpp_generate_public_key(req);
}
if (!ctx->public_key)
return -EINVAL;
/* might want less than we've got */
nbytes = min_t(size_t, ATMEL_ECC_PUBKEY_SIZE, req->dst_len);
/* public key was saved at private key generation */
copied = sg_copy_from_buffer(req->dst,
sg_nents_for_len(req->dst, nbytes),
ctx->public_key, nbytes);
if (copied != nbytes)
ret = -EINVAL;
return ret;
}
static int atmel_ecdh_compute_shared_secret(struct kpp_request *req)
{
struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
struct atmel_ecdh_ctx *ctx = kpp_tfm_ctx(tfm);
struct atmel_i2c_work_data *work_data;
gfp_t gfp;
int ret;
if (ctx->do_fallback) {
kpp_request_set_tfm(req, ctx->fallback);
return crypto_kpp_compute_shared_secret(req);
}
/* must have exactly two points to be on the curve */
if (req->src_len != ATMEL_ECC_PUBKEY_SIZE)
return -EINVAL;
gfp = (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ? GFP_KERNEL :
GFP_ATOMIC;
work_data = kmalloc(sizeof(*work_data), gfp);
if (!work_data)
return -ENOMEM;
work_data->ctx = ctx;
work_data->client = ctx->client;
ret = atmel_i2c_init_ecdh_cmd(&work_data->cmd, req->src);
if (ret)
goto free_work_data;
atmel_i2c_enqueue(work_data, atmel_ecdh_done, req);
return -EINPROGRESS;
free_work_data:
kfree(work_data);
return ret;
}
static struct i2c_client *atmel_ecc_i2c_client_alloc(void)
{
struct atmel_i2c_client_priv *i2c_priv, *min_i2c_priv = NULL;
struct i2c_client *client = ERR_PTR(-ENODEV);
int min_tfm_cnt = INT_MAX;
int tfm_cnt;
spin_lock(&driver_data.i2c_list_lock);
if (list_empty(&driver_data.i2c_client_list)) {
spin_unlock(&driver_data.i2c_list_lock);
return ERR_PTR(-ENODEV);
}
list_for_each_entry(i2c_priv, &driver_data.i2c_client_list,
i2c_client_list_node) {
tfm_cnt = atomic_read(&i2c_priv->tfm_count);
if (tfm_cnt < min_tfm_cnt) {
min_tfm_cnt = tfm_cnt;
min_i2c_priv = i2c_priv;
}
if (!min_tfm_cnt)
break;
}
if (min_i2c_priv) {
atomic_inc(&min_i2c_priv->tfm_count);
client = min_i2c_priv->client;
}
spin_unlock(&driver_data.i2c_list_lock);
return client;
}
static void atmel_ecc_i2c_client_free(struct i2c_client *client)
{
struct atmel_i2c_client_priv *i2c_priv = i2c_get_clientdata(client);
atomic_dec(&i2c_priv->tfm_count);
}
static int atmel_ecdh_init_tfm(struct crypto_kpp *tfm)
{
const char *alg = kpp_alg_name(tfm);
struct crypto_kpp *fallback;
struct atmel_ecdh_ctx *ctx = kpp_tfm_ctx(tfm);
ctx->curve_id = ECC_CURVE_NIST_P256;
ctx->client = atmel_ecc_i2c_client_alloc();
if (IS_ERR(ctx->client)) {
pr_err("tfm - i2c_client binding failed\n");
return PTR_ERR(ctx->client);
}
fallback = crypto_alloc_kpp(alg, 0, CRYPTO_ALG_NEED_FALLBACK);
if (IS_ERR(fallback)) {
dev_err(&ctx->client->dev, "Failed to allocate transformation for '%s': %ld\n",
alg, PTR_ERR(fallback));
return PTR_ERR(fallback);
}
crypto_kpp_set_flags(fallback, crypto_kpp_get_flags(tfm));
ctx->fallback = fallback;
return 0;
}
static void atmel_ecdh_exit_tfm(struct crypto_kpp *tfm)
{
struct atmel_ecdh_ctx *ctx = kpp_tfm_ctx(tfm);
kfree(ctx->public_key);
crypto_free_kpp(ctx->fallback);
atmel_ecc_i2c_client_free(ctx->client);
}
static unsigned int atmel_ecdh_max_size(struct crypto_kpp *tfm)
{
struct atmel_ecdh_ctx *ctx = kpp_tfm_ctx(tfm);
if (ctx->fallback)
return crypto_kpp_maxsize(ctx->fallback);
/*
* The device only supports NIST P256 ECC keys. The public key size will
* always be the same. Use a macro for the key size to avoid unnecessary
* computations.
*/
return ATMEL_ECC_PUBKEY_SIZE;
}
static struct kpp_alg atmel_ecdh_nist_p256 = {
.set_secret = atmel_ecdh_set_secret,
.generate_public_key = atmel_ecdh_generate_public_key,
.compute_shared_secret = atmel_ecdh_compute_shared_secret,
.init = atmel_ecdh_init_tfm,
.exit = atmel_ecdh_exit_tfm,
.max_size = atmel_ecdh_max_size,
.base = {
.cra_flags = CRYPTO_ALG_NEED_FALLBACK,
.cra_name = "ecdh-nist-p256",
.cra_driver_name = "atmel-ecdh",
.cra_priority = ATMEL_ECC_PRIORITY,
.cra_module = THIS_MODULE,
.cra_ctxsize = sizeof(struct atmel_ecdh_ctx),
},
};
static int atmel_ecc_probe(struct i2c_client *client)
{
struct atmel_i2c_client_priv *i2c_priv;
int ret;
ret = atmel_i2c_probe(client);
if (ret)
return ret;
i2c_priv = i2c_get_clientdata(client);
spin_lock(&driver_data.i2c_list_lock);
list_add_tail(&i2c_priv->i2c_client_list_node,
&driver_data.i2c_client_list);
spin_unlock(&driver_data.i2c_list_lock);
ret = crypto_register_kpp(&atmel_ecdh_nist_p256);
if (ret) {
spin_lock(&driver_data.i2c_list_lock);
list_del(&i2c_priv->i2c_client_list_node);
spin_unlock(&driver_data.i2c_list_lock);
dev_err(&client->dev, "%s alg registration failed\n",
atmel_ecdh_nist_p256.base.cra_driver_name);
} else {
dev_info(&client->dev, "atmel ecc algorithms registered in /proc/crypto\n");
}
return ret;
}
static void atmel_ecc_remove(struct i2c_client *client)
{
struct atmel_i2c_client_priv *i2c_priv = i2c_get_clientdata(client);
/* Return EBUSY if i2c client already allocated. */
if (atomic_read(&i2c_priv->tfm_count)) {
/*
* After we return here, the memory backing the device is freed.
* That happens no matter what the return value of this function
* is because in the Linux device model there is no error
* handling for unbinding a driver.
* If there is still some action pending, it probably involves
* accessing the freed memory.
*/
dev_emerg(&client->dev, "Device is busy, expect memory corruption.\n");
return;
}
crypto_unregister_kpp(&atmel_ecdh_nist_p256);
spin_lock(&driver_data.i2c_list_lock);
list_del(&i2c_priv->i2c_client_list_node);
spin_unlock(&driver_data.i2c_list_lock);
}
#ifdef CONFIG_OF
static const struct of_device_id atmel_ecc_dt_ids[] = {
{
.compatible = "atmel,atecc508a",
}, {
/* sentinel */
}
};
MODULE_DEVICE_TABLE(of, atmel_ecc_dt_ids);
#endif
static const struct i2c_device_id atmel_ecc_id[] = {
{ "atecc508a", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, atmel_ecc_id);
static struct i2c_driver atmel_ecc_driver = {
.driver = {
.name = "atmel-ecc",
.of_match_table = of_match_ptr(atmel_ecc_dt_ids),
},
.probe = atmel_ecc_probe,
.remove = atmel_ecc_remove,
.id_table = atmel_ecc_id,
};
static int __init atmel_ecc_init(void)
{
spin_lock_init(&driver_data.i2c_list_lock);
INIT_LIST_HEAD(&driver_data.i2c_client_list);
return i2c_add_driver(&atmel_ecc_driver);
}
static void __exit atmel_ecc_exit(void)
{
atmel_i2c_flush_queue();
i2c_del_driver(&atmel_ecc_driver);
}
module_init(atmel_ecc_init);
module_exit(atmel_ecc_exit);
MODULE_AUTHOR("Tudor Ambarus");
MODULE_DESCRIPTION("Microchip / Atmel ECC (I2C) driver");
MODULE_LICENSE("GPL v2");