[U-Boot] [PATCH v3 15/20] tee: add sandbox driver

Simon Glass sjg at chromium.org
Fri Sep 14 10:53:56 UTC 2018


Hi Jens,

On 3 September 2018 at 16:47, Jens Wiklander <jens.wiklander at linaro.org> wrote:
> Adds a sandboxtee driver which emulates a generic TEE with the OP-TEE

sandbox tee

> AVB TA.
>
> Signed-off-by: Jens Wiklander <jens.wiklander at linaro.org>
> ---
>  drivers/tee/Kconfig       |  12 +-
>  drivers/tee/Makefile      |   1 +
>  drivers/tee/optee/Kconfig |   2 +-
>  drivers/tee/sandbox.c     | 299 ++++++++++++++++++++++++++++++++++++++
>  include/sandboxtee.h      |  15 ++
>  5 files changed, 326 insertions(+), 3 deletions(-)
>  create mode 100644 drivers/tee/sandbox.c
>  create mode 100644 include/sandboxtee.h

Reviewed-by: Simon Glass <sjg at chromium.org>

nits below.

>
> diff --git a/drivers/tee/Kconfig b/drivers/tee/Kconfig
> index 835c256e9239..4697b80913d6 100644
> --- a/drivers/tee/Kconfig
> +++ b/drivers/tee/Kconfig
> @@ -1,8 +1,8 @@
>  # Generic Trusted Execution Environment Configuration
>  config TEE
>         bool "Trusted Execution Environment support"
> -       depends on ARM && (ARM64 || CPU_V7A)
> -       select ARM_SMCCC
> +       depends on (ARM && (ARM64 || CPU_V7A)) || SANDBOX
> +       select ARM_SMCCC if ARM
>         help
>           This implements a generic interface towards a Trusted Execution
>           Environment (TEE). A TEE is a trusted OS running in some secure
> @@ -14,6 +14,14 @@ if TEE
>
>  menu "TEE drivers"
>
> +config SANDBOX_TEE
> +       bool "Sandbox TEE emulator"
> +       depends on SANDBOX
> +       default y
> +       help
> +         This emulates a generic TEE needed for testing including the AVB
> +         TA.

Can you please expand this? What features does it implement? How do
you access it from the U-Boot command line?

> +
>  source "drivers/tee/optee/Kconfig"
>
>  endmenu
> diff --git a/drivers/tee/Makefile b/drivers/tee/Makefile
> index 19633b60f235..f72c68c09f33 100644
> --- a/drivers/tee/Makefile
> +++ b/drivers/tee/Makefile
> @@ -1,4 +1,5 @@
>  # SPDX-License-Identifier: GPL-2.0+
>
>  obj-y += tee-uclass.o
> +obj-$(CONFIG_SANDBOX) += sandbox.o
>  obj-$(CONFIG_OPTEE) += optee/
> diff --git a/drivers/tee/optee/Kconfig b/drivers/tee/optee/Kconfig
> index dbfa7846a30f..d489834df926 100644
> --- a/drivers/tee/optee/Kconfig
> +++ b/drivers/tee/optee/Kconfig
> @@ -10,7 +10,7 @@ config OPTEE
>           handle Remote Procedure Calls (RPC) from OP-TEE needed to
>           execute a service. For more information see: https://www.op-tee.org
>
> -if OPTEE
> +if OPTEE || SANDBOX
>
>  menu "OP-TEE options"
>
> diff --git a/drivers/tee/sandbox.c b/drivers/tee/sandbox.c
> new file mode 100644
> index 000000000000..cd073497615f
> --- /dev/null
> +++ b/drivers/tee/sandbox.c
> @@ -0,0 +1,299 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2018 Linaro Limited
> + */
> +#include <common.h>
> +#include <dm.h>
> +#include <sandboxtee.h>

Could this go in asm/ ?

> +#include <tee.h>
> +#include <tee/optee_ta_avb.h>
> +
> +/*
> + * The sandbox tee driver tries to emulate a generic TEE with the TA
> + * OPTEE_TA_AVB available.

What is TEE?

What is TA?

Please expand out the names once in this comment so people can see
immediately what you are referring to.

> + */
> +



> +struct ta_entry {

What is this struct for? Please add a comment

> +       struct tee_optee_ta_uuid uuid;
> +       u32 (*open_session)(uint num_params, struct tee_param *params);
> +       u32 (*invoke_func)(u32 func, uint num_params, struct tee_param *params);
> +};
> +
> +#ifdef CONFIG_OPTEE_TA_AVB
> +static u32 get_attr(uint n, uint num_params, struct tee_param *params)
> +{
> +       if (n >= num_params)
> +               return TEE_PARAM_ATTR_TYPE_NONE;
> +
> +       return params[n].attr;
> +}
> +
> +static u32 check_params(u8 p0, u8 p1, u8 p2, u8 p3, uint num_params,
> +                       struct tee_param *params)
> +{
> +       u8 p[] = { p0, p1, p2, p3};
> +       uint n;
> +
> +       for (n = 0; n < ARRAY_SIZE(p); n++)
> +               if (p[n] != get_attr(n, num_params, params))
> +                       goto bad_params;
> +
> +       for (; n < num_params; n++)
> +               if (get_attr(n, num_params, params))
> +                       goto bad_params;
> +
> +       return TEE_SUCCESS;
> +
> +bad_params:
> +       printf("Bad param attrs\n");
> +
> +       return TEE_ERROR_BAD_PARAMETERS;
> +}
> +
> +static u64 ta_avb_rollback_indexes[TA_AVB_MAX_ROLLBACK_LOCATIONS];
> +static u32 ta_avb_lock_state;
> +
> +static u32 ta_avb_open_session(uint num_params, struct tee_param *params)
> +{
> +       /*
> +        * We don't expect additional parameters when opening a session to
> +        * this TA.
> +        */
> +       return check_params(TEE_PARAM_ATTR_TYPE_NONE, TEE_PARAM_ATTR_TYPE_NONE,
> +                           TEE_PARAM_ATTR_TYPE_NONE, TEE_PARAM_ATTR_TYPE_NONE,
> +                           num_params, params);
> +}
> +
> +static u32 ta_avb_invoke_func(u32 func, uint num_params,
> +                             struct tee_param *params)
> +{
> +       u32 res;
> +       uint slot;
> +       u64 val;
> +
> +       switch (func) {
> +       case TA_AVB_CMD_READ_ROLLBACK_INDEX:
> +               res = check_params(TEE_PARAM_ATTR_TYPE_VALUE_INPUT,
> +                                  TEE_PARAM_ATTR_TYPE_VALUE_OUTPUT,
> +                                  TEE_PARAM_ATTR_TYPE_NONE,
> +                                  TEE_PARAM_ATTR_TYPE_NONE,
> +                                  num_params, params);
> +               if (res)
> +                       return res;
> +
> +               slot = params[0].u.value.a;
> +               if (slot >= ARRAY_SIZE(ta_avb_rollback_indexes)) {
> +                       printf("Rollback index slot out of bounds %lu\n", slot);
> +                       return TEE_ERROR_BAD_PARAMETERS;
> +               }
> +
> +               val = ta_avb_rollback_indexes[slot];
> +               params[1].u.value.a = val >> 32;
> +               params[1].u.value.b = val;
> +               return TEE_SUCCESS;
> +
> +       case TA_AVB_CMD_WRITE_ROLLBACK_INDEX:
> +               res = check_params(TEE_PARAM_ATTR_TYPE_VALUE_INPUT,
> +                                  TEE_PARAM_ATTR_TYPE_VALUE_INPUT,
> +                                  TEE_PARAM_ATTR_TYPE_NONE,
> +                                  TEE_PARAM_ATTR_TYPE_NONE,
> +                                  num_params, params);
> +               if (res)
> +                       return res;
> +
> +               slot = params[0].u.value.a;
> +               if (slot >= ARRAY_SIZE(ta_avb_rollback_indexes)) {
> +                       printf("Rollback index slot out of bounds %lu\n", slot);
> +                       return TEE_ERROR_BAD_PARAMETERS;
> +               }
> +
> +               val = (u64)params[1].u.value.a << 32 | params[1].u.value.b;
> +               if (val < ta_avb_rollback_indexes[slot])
> +                       return TEE_ERROR_SECURITY;
> +
> +               ta_avb_rollback_indexes[slot] = val;
> +               return TEE_SUCCESS;
> +
> +       case TA_AVB_CMD_READ_LOCK_STATE:
> +               res = check_params(TEE_PARAM_ATTR_TYPE_VALUE_OUTPUT,
> +                                  TEE_PARAM_ATTR_TYPE_NONE,
> +                                  TEE_PARAM_ATTR_TYPE_NONE,
> +                                  TEE_PARAM_ATTR_TYPE_NONE,
> +                                  num_params, params);
> +               if (res)
> +                       return res;
> +
> +               params[0].u.value.a = ta_avb_lock_state;
> +               return TEE_SUCCESS;
> +
> +       case TA_AVB_CMD_WRITE_LOCK_STATE:
> +               res = check_params(TEE_PARAM_ATTR_TYPE_VALUE_INPUT,
> +                                  TEE_PARAM_ATTR_TYPE_NONE,
> +                                  TEE_PARAM_ATTR_TYPE_NONE,
> +                                  TEE_PARAM_ATTR_TYPE_NONE,
> +                                  num_params, params);
> +               if (res)
> +                       return res;
> +
> +               if (ta_avb_lock_state != params[0].u.value.a) {
> +                       ta_avb_lock_state = params[0].u.value.a;
> +                       memset(ta_avb_rollback_indexes, 0,
> +                              sizeof(ta_avb_rollback_indexes));
> +               }
> +
> +               return TEE_SUCCESS;
> +
> +       default:
> +               return TEE_ERROR_NOT_SUPPORTED;
> +       }
> +}
> +#endif /*OPTEE_TA_AVB*/
> +
> +static const struct ta_entry ta_entries[] = {
> +#ifdef CONFIG_OPTEE_TA_AVB
> +       { .uuid = TA_AVB_UUID,
> +         .open_session = ta_avb_open_session,
> +         .invoke_func = ta_avb_invoke_func,
> +       },
> +#endif
> +};
> +
> +static void sandbox_tee_get_version(struct udevice *dev,
> +                                   struct tee_version_data *vers)
> +{
> +       struct tee_version_data v = {
> +               .gen_caps = TEE_GEN_CAP_GP | TEE_GEN_CAP_REG_MEM,
> +       };
> +
> +       *vers = v;
> +}
> +
> +static int sandbox_tee_close_session(struct udevice *dev, u32 session)
> +{
> +       struct sandbox_tee_state *state = dev_get_priv(dev);
> +
> +       if (!state->ta || state->session != session)
> +               return -EINVAL;
> +
> +       state->session = 0;
> +       state->ta = NULL;
> +
> +       return 0;
> +}
> +
> +static const struct ta_entry *find_ta_entry(u8 uuid[TEE_UUID_LEN])
> +{
> +       struct tee_optee_ta_uuid u;
> +       uint n;
> +
> +       tee_optee_ta_uuid_from_octets(&u, uuid);
> +
> +       for (n = 0; n < ARRAY_SIZE(ta_entries); n++)
> +               if (!memcmp(&u, &ta_entries[n].uuid, sizeof(u)))
> +                       return ta_entries + n;
> +
> +       return NULL;
> +}
> +
> +static int sandbox_tee_open_session(struct udevice *dev,
> +                                   struct tee_open_session_arg *arg,
> +                                   uint num_params, struct tee_param *params)
> +{
> +       struct sandbox_tee_state *state = dev_get_priv(dev);
> +       const struct ta_entry *ta;
> +
> +       if (state->ta) {
> +               printf("A session is already open\n");
> +               return -EBUSY;
> +       }
> +
> +       ta = find_ta_entry(arg->uuid);
> +       if (!ta) {
> +               printf("Cannot find TA\n");
> +               arg->ret = TEE_ERROR_ITEM_NOT_FOUND;
> +               arg->ret_origin = TEE_ORIGIN_TEE;
> +
> +               return 0;
> +       }
> +
> +       arg->ret = ta->open_session(num_params, params);
> +       arg->ret_origin = TEE_ORIGIN_TRUSTED_APP;
> +
> +       if (!arg->ret) {
> +               state->ta = (void *)ta;
> +               state->session = 1;
> +               arg->session = state->session;
> +       } else {
> +               printf("Cannot open session, TA returns error\n");
> +       }
> +
> +       return 0;
> +}
> +
> +static int sandbox_tee_invoke_func(struct udevice *dev,
> +                                  struct tee_invoke_arg *arg,
> +                                  uint num_params, struct tee_param *params)
> +{
> +       struct sandbox_tee_state *state = dev_get_priv(dev);
> +       struct ta_entry *ta = state->ta;
> +
> +       if (!arg->session) {
> +               printf("Missing session\n");
> +               return -EINVAL;
> +       }
> +
> +       if (!ta) {
> +               printf("TA session not available\n");
> +               return -EINVAL;
> +       }
> +
> +       if (arg->session != state->session) {
> +               printf("Session mismatch\n");
> +               return -EINVAL;
> +       }
> +
> +       arg->ret = ta->invoke_func(arg->func, num_params, params);
> +       arg->ret_origin = TEE_ORIGIN_TRUSTED_APP;
> +
> +       return 0;
> +}
> +
> +static int sandbox_tee_shm_register(struct udevice *dev, struct tee_shm *shm)
> +{
> +       struct sandbox_tee_state *state = dev_get_priv(dev);
> +
> +       state->num_shms++;
> +
> +       return 0;
> +}
> +
> +static int sandbox_tee_shm_unregister(struct udevice *dev, struct tee_shm *shm)
> +{
> +       struct sandbox_tee_state *state = dev_get_priv(dev);
> +
> +       state->num_shms--;
> +
> +       return 0;
> +}
> +
> +static const struct tee_driver_ops sandbox_tee_ops = {
> +       .get_version = sandbox_tee_get_version,
> +       .open_session = sandbox_tee_open_session,
> +       .close_session = sandbox_tee_close_session,
> +       .invoke_func = sandbox_tee_invoke_func,
> +       .shm_register = sandbox_tee_shm_register,
> +       .shm_unregister = sandbox_tee_shm_unregister,
> +};
> +
> +static const struct udevice_id sandbox_tee_match[] = {
> +       { .compatible = "sandbox,tee" },
> +       {},
> +};
> +
> +U_BOOT_DRIVER(sandbox_tee) = {
> +       .name = "sandbox_tee",
> +       .id = UCLASS_TEE,
> +       .of_match = sandbox_tee_match,
> +       .ops = &sandbox_tee_ops,
> +       .priv_auto_alloc_size = sizeof(struct sandbox_tee_state),
> +};
> diff --git a/include/sandboxtee.h b/include/sandboxtee.h
> new file mode 100644
> index 000000000000..59cbb621820b
> --- /dev/null
> +++ b/include/sandboxtee.h
> @@ -0,0 +1,15 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * Copyright (C) 2018 Linaro Limited
> + */
> +
> +#ifndef __SANDBOXTEE_H
> +#define __SANDBOXTEE_H
> +
> +struct sandbox_tee_state {
> +       u32 session;
> +       int num_shms;
> +       void *ta;

struct/members need comments

> +};
> +
> +#endif /*__SANDBOXTEE_H*/
> --
> 2.17.1
>

Regards,
Simon


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