From: Bhaumik Bhatt <bbhatt@xxxxxxxxxxxxxx> commit 546362a9ef2ef40b57c6605f14e88ced507f8dd0 upstream. 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. Link: https://lore.kernel.org/r/1624558141-11045-1-git-send-email-bbhatt@xxxxxxxxxxxxxx Fixes: 1d3173a3bae7 ("bus: mhi: core: Add support for processing events from client device") Cc: stable@xxxxxxxxxxxxxxx #5.10 Reviewed-by: Hemant Kumar <hemantk@xxxxxxxxxxxxxx> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> Reviewed-by: Jeffrey Hugo <quic_jhugo@xxxxxxxxxxx> Signed-off-by: Bhaumik Bhatt <bbhatt@xxxxxxxxxxxxxx> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> Link: https://lore.kernel.org/r/20210716075106.49938-3-manivannan.sadhasivam@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/bus/mhi/core/main.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) --- a/drivers/bus/mhi/core/main.c +++ b/drivers/bus/mhi/core/main.c @@ -706,11 +706,18 @@ static void mhi_process_cmd_completion(s 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); }
