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From:   Bhaumik Bhatt <bbhatt@codeaurora.org>
To:     mani@kernel.org
Cc:     linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
        hemantk@codeaurora.org
Subject: [PATCH v1 2/8] bus: mhi: core: Add range check for channel id received in event ring
Date:   Mon, 27 Apr 2020 11:32:16 -0700
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From: Hemant Kumar <hemantk@codeaurora.org>

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@codeaurora.org>
---
 drivers/bus/mhi/core/main.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index 23154f1..ba8afa7 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -827,6 +827,9 @@ 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);
+		if (WARN_ON(chan >= mhi_cntrl->max_chan))
+			continue;
+
 		mhi_chan = &mhi_cntrl->mhi_chan[chan];
 
 		if (likely(type == MHI_PKT_TYPE_TX_EVENT)) {
-- 
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