Messages in this thread Patch in this message | | | From | Jia-Ju Bai <> | Subject | [PATCH] usb: cdns3: fix possible buffer overflow caused by bad DMA value | Date | Sat, 30 May 2020 11:24:00 +0800 |
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In cdns3_ep0_setup_phase(): struct usb_ctrlrequest *ctrl = priv_dev->setup_buf;
Because priv_dev->setup_buf (allocated in cdns3_gadget_start) is stored in DMA memory, and thus ctrl is a DMA value.
cdns3_ep0_setup_phase() cdns3_ep0_standard_request(priv_dev, ctrl) cdns3_req_ep0_get_status(priv_dev, ctrl) index = cdns3_ep_addr_to_index(ctrl->wIndex); priv_ep = priv_dev->eps[index];
cdns3_ep0_setup_phase() cdns3_ep0_standard_request(priv_dev, ctrl) cdns3_req_ep0_handle_feature(priv_dev, ctrl_req, 0) cdns3_ep0_feature_handle_endpoint(priv_dev, ctrl, set) index = cdns3_ep_addr_to_index(ctrl->wIndex); priv_ep = priv_dev->eps[index];
In these cases, ctrl->wIndex can be be modified at anytime by malicious hardware, and thus a buffer overflow can occur when the code "priv_dev->eps[index]" is executed.
To fix these possible bugs, index is checked before being used.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> --- drivers/usb/cdns3/ep0.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/drivers/usb/cdns3/ep0.c b/drivers/usb/cdns3/ep0.c index e71240b386b4..0a80c7ade613 100644 --- a/drivers/usb/cdns3/ep0.c +++ b/drivers/usb/cdns3/ep0.c @@ -265,6 +265,8 @@ static int cdns3_req_ep0_get_status(struct cdns3_device *priv_dev, return cdns3_ep0_delegate_req(priv_dev, ctrl); case USB_RECIP_ENDPOINT: index = cdns3_ep_addr_to_index(ctrl->wIndex); + if (index >= CDNS3_ENDPOINTS_MAX_COUNT) + return -EINVAL; priv_ep = priv_dev->eps[index]; /* check if endpoint is stalled or stall is pending */ @@ -388,6 +390,9 @@ static int cdns3_ep0_feature_handle_endpoint(struct cdns3_device *priv_dev, return 0; index = cdns3_ep_addr_to_index(ctrl->wIndex); + if (index >= CDNS3_ENDPOINTS_MAX_COUNT) + return -EINVAL; + priv_ep = priv_dev->eps[index]; cdns3_select_ep(priv_dev, ctrl->wIndex); -- 2.17.1
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