// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2019-2021 Linaro Ltd.
*
* Author:
* Sumit Garg <[email protected]>
*/
#include <linux/err.h>
#include <linux/key-type.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/tee_drv.h>
#include <linux/uuid.h>
#include <keys/trusted_tee.h>
#define DRIVER_NAME "trusted-key-tee"
/*
* Get random data for symmetric key
*
* [out] memref[0] Random data
*/
#define TA_CMD_GET_RANDOM 0x0
/*
* Seal trusted key using hardware unique key
*
* [in] memref[0] Plain key
* [out] memref[1] Sealed key datablob
*/
#define TA_CMD_SEAL 0x1
/*
* Unseal trusted key using hardware unique key
*
* [in] memref[0] Sealed key datablob
* [out] memref[1] Plain key
*/
#define TA_CMD_UNSEAL 0x2
/**
* struct trusted_key_tee_private - TEE Trusted key private data
* @dev: TEE based Trusted key device.
* @ctx: TEE context handler.
* @session_id: Trusted key TA session identifier.
* @shm_pool: Memory pool shared with TEE device.
*/
struct trusted_key_tee_private {
struct device *dev;
struct tee_context *ctx;
u32 session_id;
struct tee_shm *shm_pool;
};
static struct trusted_key_tee_private pvt_data;
/*
* Have the TEE seal(encrypt) the symmetric key
*/
static int trusted_tee_seal(struct trusted_key_payload *p, char *datablob)
{
int ret;
struct tee_ioctl_invoke_arg inv_arg;
struct tee_param param[4];
struct tee_shm *reg_shm = NULL;
memset(&inv_arg, 0, sizeof(inv_arg));
memset(¶m, 0, sizeof(param));
reg_shm = tee_shm_register_kernel_buf(pvt_data.ctx, p->key,
sizeof(p->key) + sizeof(p->blob));
if (IS_ERR(reg_shm)) {
dev_err(pvt_data.dev, "shm register failed\n");
return PTR_ERR(reg_shm);
}
inv_arg.func = TA_CMD_SEAL;
inv_arg.session = pvt_data.session_id;
inv_arg.num_params = 4;
param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT;
param[0].u.memref.shm = reg_shm;
param[0].u.memref.size = p->key_len;
param[0].u.memref.shm_offs = 0;
param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
param[1].u.memref.shm = reg_shm;
param[1].u.memref.size = sizeof(p->blob);
param[1].u.memref.shm_offs = sizeof(p->key);
ret = tee_client_invoke_func(pvt_data.ctx, &inv_arg, param);
if ((ret < 0) || (inv_arg.ret != 0)) {
dev_err(pvt_data.dev, "TA_CMD_SEAL invoke err: %x\n",
inv_arg.ret);
ret = -EFAULT;
} else {
p->blob_len = param[1].u.memref.size;
}
tee_shm_free(reg_shm);
return ret;
}
/*
* Have the TEE unseal(decrypt) the symmetric key
*/
static int trusted_tee_unseal(struct trusted_key_payload *p, char *datablob)
{
int ret;
struct tee_ioctl_invoke_arg inv_arg;
struct tee_param param[4];
struct tee_shm *reg_shm = NULL;
memset(&inv_arg, 0, sizeof(inv_arg));
memset(¶m, 0, sizeof(param));
reg_shm = tee_shm_register_kernel_buf(pvt_data.ctx, p->key,
sizeof(p->key) + sizeof(p->blob));
if (IS_ERR(reg_shm)) {
dev_err(pvt_data.dev, "shm register failed\n");
return PTR_ERR(reg_shm);
}
inv_arg.func = TA_CMD_UNSEAL;
inv_arg.session = pvt_data.session_id;
inv_arg.num_params = 4;
param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT;
param[0].u.memref.shm = reg_shm;
param[0].u.memref.size = p->blob_len;
param[0].u.memref.shm_offs = sizeof(p->key);
param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
param[1].u.memref.shm = reg_shm;
param[1].u.memref.size = sizeof(p->key);
param[1].u.memref.shm_offs = 0;
ret = tee_client_invoke_func(pvt_data.ctx, &inv_arg, param);
if ((ret < 0) || (inv_arg.ret != 0)) {
dev_err(pvt_data.dev, "TA_CMD_UNSEAL invoke err: %x\n",
inv_arg.ret);
ret = -EFAULT;
} else {
p->key_len = param[1].u.memref.size;
}
tee_shm_free(reg_shm);
return ret;
}
/*
* Have the TEE generate random symmetric key
*/
static int trusted_tee_get_random(unsigned char *key, size_t key_len)
{
int ret;
struct tee_ioctl_invoke_arg inv_arg;
struct tee_param param[4];
struct tee_shm *reg_shm = NULL;
memset(&inv_arg, 0, sizeof(inv_arg));
memset(¶m, 0, sizeof(param));
reg_shm = tee_shm_register_kernel_buf(pvt_data.ctx, key, key_len);
if (IS_ERR(reg_shm)) {
dev_err(pvt_data.dev, "key shm register failed\n");
return PTR_ERR(reg_shm);
}
inv_arg.func = TA_CMD_GET_RANDOM;
inv_arg.session = pvt_data.session_id;
inv_arg.num_params = 4;
param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
param[0].u.memref.shm = reg_shm;
param[0].u.memref.size = key_len;
param[0].u.memref.shm_offs = 0;
ret = tee_client_invoke_func(pvt_data.ctx, &inv_arg, param);
if ((ret < 0) || (inv_arg.ret != 0)) {
dev_err(pvt_data.dev, "TA_CMD_GET_RANDOM invoke err: %x\n",
inv_arg.ret);
ret = -EFAULT;
} else {
ret = param[0].u.memref.size;
}
tee_shm_free(reg_shm);
return ret;
}
static int optee_ctx_match(struct tee_ioctl_version_data *ver, const void *data)
{
if (ver->impl_id == TEE_IMPL_ID_OPTEE &&
ver->gen_caps & TEE_GEN_CAP_REG_MEM)
return 1;
else
return 0;
}
static int trusted_key_probe(struct device *dev)
{
struct tee_client_device *rng_device = to_tee_client_device(dev);
int ret;
struct tee_ioctl_open_session_arg sess_arg;
memset(&sess_arg, 0, sizeof(sess_arg));
pvt_data.ctx = tee_client_open_context(NULL, optee_ctx_match, NULL,
NULL);
if (IS_ERR(pvt_data.ctx))
return -ENODEV;
memcpy(sess_arg.uuid, rng_device->id.uuid.b, TEE_IOCTL_UUID_LEN);
sess_arg.clnt_login = TEE_IOCTL_LOGIN_REE_KERNEL;
sess_arg.num_params = 0;
ret = tee_client_open_session(pvt_data.ctx, &sess_arg, NULL);
if ((ret < 0) || (sess_arg.ret != 0)) {
dev_err(dev, "tee_client_open_session failed, err: %x\n",
sess_arg.ret);
ret = -EINVAL;
goto out_ctx;
}
pvt_data.session_id = sess_arg.session;
ret = register_key_type(&key_type_trusted);
if (ret < 0)
goto out_sess;
pvt_data.dev = dev;
return 0;
out_sess:
tee_client_close_session(pvt_data.ctx, pvt_data.session_id);
out_ctx:
tee_client_close_context(pvt_data.ctx);
return ret;
}
static int trusted_key_remove(struct device *dev)
{
unregister_key_type(&key_type_trusted);
tee_client_close_session(pvt_data.ctx, pvt_data.session_id);
tee_client_close_context(pvt_data.ctx);
return 0;
}
static const struct tee_client_device_id trusted_key_id_table[] = {
{UUID_INIT(0xf04a0fe7, 0x1f5d, 0x4b9b,
0xab, 0xf7, 0x61, 0x9b, 0x85, 0xb4, 0xce, 0x8c)},
{}
};
MODULE_DEVICE_TABLE(tee, trusted_key_id_table);
static struct tee_client_driver trusted_key_driver = {
.id_table = trusted_key_id_table,
.driver = {
.name = DRIVER_NAME,
.bus = &tee_bus_type,
.probe = trusted_key_probe,
.remove = trusted_key_remove,
},
};
static int trusted_tee_init(void)
{
return driver_register(&trusted_key_driver.driver);
}
static void trusted_tee_exit(void)
{
driver_unregister(&trusted_key_driver.driver);
}
struct trusted_key_ops trusted_key_tee_ops = {
.migratable = 0, /* non-migratable */
.init = trusted_tee_init,
.seal = trusted_tee_seal,
.unseal = trusted_tee_unseal,
.get_random = trusted_tee_get_random,
.exit = trusted_tee_exit,
};
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