[PATCH v1] tee: sandbox: check for buffer size

[Ilias Apalodimas]

On Sun, Apr 21, 2024 at 10:48:39PM +0200, Igor Opaniuk wrote:
> Add additional check for buffer size when reading out persistent
> storage value and provide back actual value size.
>
> Signed-off-by: Igor Opaniuk <igor.opaniuk at gmail.com>
> ---
>
>  drivers/tee/sandbox.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/tee/sandbox.c b/drivers/tee/sandbox.c
> index 8ad7c09efdd..86b16a3bb8d 100644
> --- a/drivers/tee/sandbox.c
> +++ b/drivers/tee/sandbox.c
> @@ -174,7 +174,7 @@ static u32 ta_avb_invoke_func(struct udevice *dev, u32 func, uint num_params,
>  	uint slot;
>  	u64 val;
>  	char *value;
> -	u32 value_sz;
> +	u32 value_sz, tmp_sz;
>
>  	switch (func) {
>  	case TA_AVB_CMD_READ_ROLLBACK_INDEX:
> @@ -267,8 +267,12 @@ static u32 ta_avb_invoke_func(struct udevice *dev, u32 func, uint num_params,
>  		if (!ep)
>  			return TEE_ERROR_ITEM_NOT_FOUND;
>
> -		value_sz = strlen(ep->data) + 1;
> -		memcpy(value, ep->data, value_sz);
> +		tmp_sz = strlen(ep->data) + 1;
> +		if (value_sz < tmp_sz)
> +			return TEE_ERROR_SHORT_BUFFER;
> +
> +		memcpy(value, ep->data, tmp_sz);
> +		params[1].u.memref.size = tmp_sz;
>
>  		return TEE_SUCCESS;
>  	case TA_AVB_CMD_WRITE_PERSIST_VALUE:
> --
> 2.34.1
>

Reviewed-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>