Re: [PATCH 1/6] tee: qcomtee: Track the object invocation context

[Amirreza Zarrabi]

Hi Harshal,

On 7/7/2026 4:11 PM, Harshal Dev wrote:
> QCOMTEE needs to distinguish between object invocations arriving from
> kernel clients and user-space clients in order to correctly marshal
> UBUF parameters and decide whether certain operations should be permitted.
> 
> Add a kernel_ctx flag to struct qcomtee_object_invoke_context to track
> the context of object invocation. Objects invoked from the kernel-space
> are expected to have the MSB of their 64-bit object-id set to indicate a
> kernel context, whereas objects invoked from user-space should not set it.
> To ensure this, we restrict the object-id space of user-space invoked
> objects to 32-bits. This is in-line with QTEE expectation of 32-bit object
> ids.
> 
> Signed-off-by: Amirreza Zarrabi <amirreza.zarrabi@xxxxxxxxxxxxxxxx>
> Signed-off-by: Harshal Dev <harshal.dev@xxxxxxxxxxxxxxxx>
> ---
>  drivers/tee/qcomtee/call.c           | 24 ++++++++++++++++++++++--
>  drivers/tee/qcomtee/qcomtee.h        |  6 ++++++
>  drivers/tee/qcomtee/qcomtee_object.h |  8 ++++++--
>  drivers/tee/tee_core.c               |  4 ++++
>  4 files changed, 38 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/tee/qcomtee/call.c b/drivers/tee/qcomtee/call.c
> index 0efc5646242a..a74a54d67b06 100644
> --- a/drivers/tee/qcomtee/call.c
> +++ b/drivers/tee/qcomtee/call.c
> @@ -397,11 +397,31 @@ static int qcomtee_object_invoke(struct tee_context *ctx,
>  {
>  	struct qcomtee_context_data *ctxdata = ctx->data;
>  	struct qcomtee_object *object;
> +	bool kernel_ctx = false;
>  	int i, ret, result;
>  
>  	if (qcomtee_params_check(params, arg->num_params))
>  		return -EINVAL;
>  
> +	/* Obtain the invocation context information from the MSB of the object
> +	 * `id` field.
> +	 */
> +	kernel_ctx = QCOMTEE_GET_CLIENT_CTX(arg->id);
> +	/* User-space identifies a NULL object via a 32-bit TEE_OBJREF_NULL id, whereas
> +	 * the kernel uses as 64-bit object-id. Hence, we check for a NULL object by
> +	 * sign-extending the object-id to 64 bits. If user-space is indeed invoking a
> +	 * NULL object we must extend the object-id to 64-bits from here on so that
> +	 * QCOMTEE can recognize it.
> +	 */
> +	if (!kernel_ctx && ((s64)(s32)arg->id) == TEE_OBJREF_NULL)
> +		arg->id = TEE_OBJREF_NULL;

Does it need to be MSB -- why bit 63? the object ID supported by QTEE is 32-bit anyway.
Let's mask the upper 32-bit and do something like kernel_ctx = !!upper_32_bits(id).
What do you think?

> +
> +	/* If the object being invoked is not NULL, drop the MSB from the `id` field to
> +	 * obtain the actual object-id.
> +	 */
> +	if (arg->id != TEE_OBJREF_NULL)
> +		arg->id = QCOMTEE_SANITIZE_OBJ_ID(arg->id);
> +
>  	/* First, handle reserved operations: */
>  	if (arg->op == QCOMTEE_MSG_OBJECT_OP_RELEASE) {
>  		del_qtee_object(arg->id, ctxdata);
> @@ -411,7 +431,7 @@ static int qcomtee_object_invoke(struct tee_context *ctx,
>  
>  	/* Otherwise, invoke a QTEE object: */
>  	struct qcomtee_object_invoke_ctx *oic __free(kfree) =
> -		qcomtee_object_invoke_ctx_alloc(ctx);
> +		qcomtee_object_invoke_ctx_alloc(ctx, kernel_ctx);
>  	if (!oic)
>  		return -ENOMEM;
>  
> @@ -648,7 +668,7 @@ static void qcomtee_get_qtee_feature_list(struct tee_context *ctx, u32 id,
>  	int result;
>  
>  	struct qcomtee_object_invoke_ctx *oic __free(kfree) =
> -		qcomtee_object_invoke_ctx_alloc(ctx);
> +		qcomtee_object_invoke_ctx_alloc(ctx, true);
>  	if (!oic)
>  		return;
>  
> diff --git a/drivers/tee/qcomtee/qcomtee.h b/drivers/tee/qcomtee/qcomtee.h
> index f39bf63fd1c2..5d292a2ff83d 100644
> --- a/drivers/tee/qcomtee/qcomtee.h
> +++ b/drivers/tee/qcomtee/qcomtee.h
> @@ -17,6 +17,12 @@
>  #define QCOMTEE_OBJREF_FLAG_USER	BIT(1)
>  #define QCOMTEE_OBJREF_FLAG_MEM		BIT(2)
>  
> +/* The MSB of the object_id field indicates whether the client is invoking the
> + * object from user context or kernel context.
> + */
> +#define QCOMTEE_GET_CLIENT_CTX(x) (((x) >> 63) & 1U)
> +#define QCOMTEE_SANITIZE_OBJ_ID(x) ((x) & (BIT(63) - 1))
> +
>  /**
>   * struct qcomtee - Main service struct.
>   * @teedev: client device.
> diff --git a/drivers/tee/qcomtee/qcomtee_object.h b/drivers/tee/qcomtee/qcomtee_object.h
> index 8b4401ecad48..2528d07e4576 100644
> --- a/drivers/tee/qcomtee/qcomtee_object.h
> +++ b/drivers/tee/qcomtee/qcomtee_object.h
> @@ -146,6 +146,7 @@ static inline int qcomtee_args_len(struct qcomtee_arg *args)
>   * struct qcomtee_object_invoke_ctx - QTEE context for object invocation.
>   * @ctx: TEE context for this invocation.
>   * @flags: flags for the invocation context.
> + * @kernel_ctx: flag that indicates this context is owned by a kernel client.
>   * @errno: error code for the invocation.
>   * @object: current object invoked in this callback context.
>   * @u: array of arguments for the current invocation (+1 for ending arg).
> @@ -158,6 +159,7 @@ static inline int qcomtee_args_len(struct qcomtee_arg *args)
>  struct qcomtee_object_invoke_ctx {
>  	struct tee_context *ctx;
>  	unsigned long flags;
> +	bool kernel_ctx;
>  	int errno;
>  
>  	struct qcomtee_object *object;
> @@ -172,13 +174,15 @@ struct qcomtee_object_invoke_ctx {
>  };
>  
>  static inline struct qcomtee_object_invoke_ctx *
> -qcomtee_object_invoke_ctx_alloc(struct tee_context *ctx)
> +qcomtee_object_invoke_ctx_alloc(struct tee_context *ctx, bool kernel_ctx)
>  {
>  	struct qcomtee_object_invoke_ctx *oic;
>  
>  	oic = kzalloc_obj(*oic);
> -	if (oic)
> +	if (oic) {
>  		oic->ctx = ctx;
> +		oic->kernel_ctx = kernel_ctx;
> +	}
>  	return oic;
>  }
>  
> diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c
> index ef9642d72672..7f986d7fb47f 100644
> --- a/drivers/tee/tee_core.c
> +++ b/drivers/tee/tee_core.c
> @@ -706,6 +706,10 @@ static int tee_ioctl_object_invoke(struct tee_context *ctx,
>  			goto out;
>  	}
>  
> +	/* Userspace object-ids are restricted to 32-bits. */
> +	if (arg.id > U32_MAX)
> +		return -EINVAL;
> +

This change belongs to tee SS, move it to a separate commit with appropriate message.

>  	rc = ctx->teedev->desc->ops->object_invoke_func(ctx, &arg, params);
>  	if (rc)
>  		goto out;
> 

Regards,
Amir