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