Re: [PATCH] soundwire: qcom: handle return correctly in qcom_swrm_transport_params

[Kees Cook]

On Thu, Apr 01, 2021 at 10:15:02AM +0100, Srinivas Kandagatla wrote:
> Looks like return from reg_write is set but not checked.
> Fix this by adding error return path.
> 
> Reported-by: coverity-bot <keescook+coverity-...@chromium.org>
> Addresses-Coverity-ID: 1503591 ("UNUSED_VALUE")
> Fixes: 128eaf937adb ("soundwire: qcom: add support to missing transport 
> params")
> Signed-off-by: Srinivas Kandagatla <srinivas.kandaga...@linaro.org>

Thanks for fixing this!

Reviewed-by: Kees Cook <keesc...@chromium.org>

-Kees

> ---
>  drivers/soundwire/qcom.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c
> index 5fd4a99cc8ac..348d9a46f850 100644
> --- a/drivers/soundwire/qcom.c
> +++ b/drivers/soundwire/qcom.c
> @@ -731,17 +731,23 @@ static int qcom_swrm_transport_params(struct sdw_bus 
> *bus,
>       value |= pcfg->si;
>  
>       ret = ctrl->reg_write(ctrl, reg, value);
> +     if (ret)
> +             goto err;
>  
>       if (pcfg->lane_control != SWR_INVALID_PARAM) {
>               reg = SWRM_DP_PORT_CTRL_2_BANK(params->port_num, bank);
>               value = pcfg->lane_control;
>               ret = ctrl->reg_write(ctrl, reg, value);
> +             if (ret)
> +                     goto err;
>       }
>  
>       if (pcfg->blk_group_count != SWR_INVALID_PARAM) {
>               reg = SWRM_DP_BLOCK_CTRL2_BANK(params->port_num, bank);
>               value = pcfg->blk_group_count;
>               ret = ctrl->reg_write(ctrl, reg, value);
> +             if (ret)
> +                     goto err;
>       }
>  
>       if (pcfg->hstart != SWR_INVALID_PARAM
> @@ -755,11 +761,15 @@ static int qcom_swrm_transport_params(struct sdw_bus 
> *bus,
>               ret = ctrl->reg_write(ctrl, reg, value);
>       }
>  
> +     if (ret)
> +             goto err;
> +
>       if (pcfg->bp_mode != SWR_INVALID_PARAM) {
>               reg = SWRM_DP_BLOCK_CTRL3_BANK(params->port_num, bank);
>               ret = ctrl->reg_write(ctrl, reg, pcfg->bp_mode);
>       }
>  
> +err:
>       return ret;
>  }
>  
> -- 
> 2.21.0
> 

-- 
Kees Cook