From: Bhaumik Bhatt bbhatt@codeaurora.org
MHI reads the channel ID from the event ring element sent by the device which can be any value between 0 and 255. In order to prevent any out of bound accesses, add a check against the maximum number of channels supported by the controller and those channels not configured yet so as to skip processing of that event ring element.
Cc: stable@vger.kernel.org #5.10 Fixes: 1d3173a3bae7 ("bus: mhi: core: Add support for processing events from client device") Signed-off-by: Bhaumik Bhatt bbhatt@codeaurora.org Reviewed-by: Hemant Kumar hemantk@codeaurora.org Reviewed-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org Reviewed-by: Jeffrey Hugo quic_jhugo@quicinc.com Link: https://lore.kernel.org/r/1624558141-11045-1-git-send-email-bbhatt@codeauror... Signed-off-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org --- drivers/bus/mhi/core/main.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c index 22acde118bc3..fc9196f11cb7 100644 --- a/drivers/bus/mhi/core/main.c +++ b/drivers/bus/mhi/core/main.c @@ -773,11 +773,18 @@ static void mhi_process_cmd_completion(struct mhi_controller *mhi_cntrl, cmd_pkt = mhi_to_virtual(mhi_ring, ptr);
chan = MHI_TRE_GET_CMD_CHID(cmd_pkt); - mhi_chan = &mhi_cntrl->mhi_chan[chan]; - write_lock_bh(&mhi_chan->lock); - mhi_chan->ccs = MHI_TRE_GET_EV_CODE(tre); - complete(&mhi_chan->completion); - write_unlock_bh(&mhi_chan->lock); + + if (chan < mhi_cntrl->max_chan && + mhi_cntrl->mhi_chan[chan].configured) { + mhi_chan = &mhi_cntrl->mhi_chan[chan]; + write_lock_bh(&mhi_chan->lock); + mhi_chan->ccs = MHI_TRE_GET_EV_CODE(tre); + complete(&mhi_chan->completion); + write_unlock_bh(&mhi_chan->lock); + } else { + dev_err(&mhi_cntrl->mhi_dev->dev, + "Completion packet for invalid channel ID: %d\n", chan); + }
mhi_del_ring_element(mhi_cntrl, mhi_ring); }