Re: [PATCH v3 4/9] bus: mhi: core: Read transfer length from an event properly

From: Jeffrey Hugo
Date: Thu Apr 30 2020 - 10:28:34 EST


On 4/29/2020 2:52 PM, Bhaumik Bhatt wrote:
From: Hemant Kumar <hemantk@xxxxxxxxxxxxxx>

When MHI Driver receives an EOT event, it reads xfer_len from the
event in the last TRE. The value is under control of the MHI device
and never validated by Host MHI driver. The value should never be
larger than the real size of the buffer but a malicious device can
set the value 0xFFFF as maximum. This causes driver to memory
overflow (both read or write). Fix this issue by reading minimum of
transfer length from event and the buffer length provided.

Signed-off-by: Hemant Kumar <hemantk@xxxxxxxxxxxxxx>
Signed-off-by: Bhaumik Bhatt <bbhatt@xxxxxxxxxxxxxx>
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Reviewed-by: Jeffrey Hugo <jhugo@xxxxxxxxxxxxxx>

--
Jeffrey Hugo
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.