[PATCH] efi_loader: Check for the native OP-TEE result on mm_communicate calls

[Heinrich Schuchardt]

On 22.07.20 09:32, Ilias Apalodimas wrote:
> Currently we only check for the return value of tee_invoke_func().
> Although OP-TEE and StMM will correctly set param[1].u.value.a and we'll
> eventually return an error, the correct thing to do is check for the
> OP_TEE return code as well.
> So let's check for that and move tee_shm_free() and tee_close_session()
> before exiting with an error to make sure we always clear the registered
> memory.
>
> Fixes: f042e47e8fb43 ("efi_loader: Implement EFI variable handling via OP-TEE")
> Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>> ---
>  lib/efi_loader/efi_variable_tee.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/lib/efi_loader/efi_variable_tee.c b/lib/efi_loader/efi_variable_tee.c
> index c0423489388a..346f4c786f28 100644
> --- a/lib/efi_loader/efi_variable_tee.c
> +++ b/lib/efi_loader/efi_variable_tee.c
> @@ -100,10 +100,10 @@ static efi_status_t optee_mm_communicate(void *comm_buf, ulong dsize)
>  	param[1].attr = TEE_PARAM_ATTR_TYPE_VALUE_OUTPUT;
>
>  	rc = tee_invoke_func(conn.tee, &arg, 2, param);
> -	if (rc)
> -		return EFI_INVALID_PARAMETER;
>  	tee_shm_free(shm);
>  	tee_close_session(conn.tee, conn.session);
> +	if (rc || arg.ret != TEE_SUCCESS)
> +		return EFI_INVALID_PARAMETER;

I will use EFI_DEVICE_ERROR here when merging as this indicates an
internal problem in contrast to a problem caused by the caller of the
UEFI API.

Reviewed-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
>
>  	switch (param[1].u.value.a) {
>  	case ARM_SMC_MM_RET_SUCCESS:
>