Messages in this thread | | | Subject | Re: [PATCH v2 3/8] bus: mhi: core: Read transfer length from an event properly | From | Hemant Kumar <> | Date | Wed, 29 Apr 2020 10:30:19 -0700 |
| |
Hi Jeff
On 4/28/20 7:50 AM, Jeffrey Hugo wrote: > On 4/27/2020 8:59 PM, Bhaumik Bhatt wrote: >> From: Hemant Kumar <hemantk@codeaurora.org> >> >> 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 device to memory > > The device will overflow, or the driver? Done. > >> 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@codeaurora.org> >> Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org> >> --- >> drivers/bus/mhi/core/main.c | 5 ++++- >> 1 file changed, 4 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c >> index 1ccd4cc..3d468d9 100644 >> --- a/drivers/bus/mhi/core/main.c >> +++ b/drivers/bus/mhi/core/main.c >> @@ -521,7 +521,10 @@ static int parse_xfer_event(struct mhi_controller >> *mhi_cntrl, >> mhi_cntrl->unmap_single(mhi_cntrl, buf_info); >> result.buf_addr = buf_info->cb_buf; >> - result.bytes_xferd = xfer_len; >> + >> + /* truncate to buf len if xfer_len is larger */ >> + result.bytes_xferd = >> + min_t(u16, xfer_len, buf_info->len); >> mhi_del_ring_element(mhi_cntrl, buf_ring); >> mhi_del_ring_element(mhi_cntrl, tre_ring); >> local_rp = tre_ring->rp; >> > >
-- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
| |