On Fri, May 08, 2020 at 07:26:43PM -0700, Bhaumik Bhatt wrote:
> From: Hemant Kumar <hemantk@xxxxxxxxxxxxxx>
>
> MHI data completion handler function reads channel id from event
> ring element. Value is under the control of MHI devices and can be
> any value between 0 and 255. In order to prevent out of bound access
> add a bound check against the max channel supported by controller
> and skip processing of that event ring element.
>
> Signed-off-by: Hemant Kumar <hemantk@xxxxxxxxxxxxxx>
> Signed-off-by: Bhaumik Bhatt <bbhatt@xxxxxxxxxxxxxx>
> Reviewed-by: Jeffrey Hugo <jhugo@xxxxxxxxxxxxxx>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
Thanks,
Mani
> ---
> drivers/bus/mhi/core/main.c | 40 +++++++++++++++++++++++++++++-----------
> 1 file changed, 29 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
> index 605640c..30798ec 100644
> --- a/drivers/bus/mhi/core/main.c
> +++ b/drivers/bus/mhi/core/main.c
> @@ -775,9 +775,18 @@ int mhi_process_ctrl_ev_ring(struct mhi_controller *mhi_cntrl,
> }
> case MHI_PKT_TYPE_TX_EVENT:
> chan = MHI_TRE_GET_EV_CHID(local_rp);
> - mhi_chan = &mhi_cntrl->mhi_chan[chan];
> - parse_xfer_event(mhi_cntrl, local_rp, mhi_chan);
> - event_quota--;
> +
> + WARN_ON(chan >= mhi_cntrl->max_chan);
> +
> + /*
> + * Only process the event ring elements whose channel
> + * ID is within the maximum supported range.
> + */
> + if (chan < mhi_cntrl->max_chan) {
> + mhi_chan = &mhi_cntrl->mhi_chan[chan];
> + parse_xfer_event(mhi_cntrl, local_rp, mhi_chan);
> + event_quota--;
> + }
> break;
> default:
> dev_err(dev, "Unhandled event type: %d\n", type);
> @@ -820,14 +829,23 @@ int mhi_process_data_event_ring(struct mhi_controller *mhi_cntrl,
> enum mhi_pkt_type type = MHI_TRE_GET_EV_TYPE(local_rp);
>
> chan = MHI_TRE_GET_EV_CHID(local_rp);
> - mhi_chan = &mhi_cntrl->mhi_chan[chan];
> -
> - if (likely(type == MHI_PKT_TYPE_TX_EVENT)) {
> - parse_xfer_event(mhi_cntrl, local_rp, mhi_chan);
> - event_quota--;
> - } else if (type == MHI_PKT_TYPE_RSC_TX_EVENT) {
> - parse_rsc_event(mhi_cntrl, local_rp, mhi_chan);
> - event_quota--;
> +
> + WARN_ON(chan >= mhi_cntrl->max_chan);
> +
> + /*
> + * Only process the event ring elements whose channel
> + * ID is within the maximum supported range.
> + */
> + if (chan < mhi_cntrl->max_chan) {
> + mhi_chan = &mhi_cntrl->mhi_chan[chan];
> +
> + if (likely(type == MHI_PKT_TYPE_TX_EVENT)) {
> + parse_xfer_event(mhi_cntrl, local_rp, mhi_chan);
> + event_quota--;
> + } else if (type == MHI_PKT_TYPE_RSC_TX_EVENT) {
> + parse_rsc_event(mhi_cntrl, local_rp, mhi_chan);
> + event_quota--;
> + }
> }
>
> mhi_recycle_ev_ring_element(mhi_cntrl, ev_ring);
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
