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.
Fixes: 1d3173a3bae7 ("bus: mhi: core: Add support for processing events from client device")
Signed-off-by: Bhaumik Bhatt <bbhatt@xxxxxxxxxxxxxx>
Reviewed-by: Hemant Kumar <hemantk@xxxxxxxxxxxxxx>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
Reviewed-by: Jeffrey Hugo <quic_jhugo@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/1619481538-4435-1-git-send-email-bbhatt@xxxxxxxxxxxxxx
---
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 22acde1..fc9196f 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);
}
--
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