From: Heiko Stuebner heiko.stuebner@theobroma-systems.com
commit f670e9f9c8cac716c3506c6bac9e997b27ad441a upstream.
dwc2_hsotg_process_req_status uses ep_from_windex() to retrieve the endpoint for the index provided in the wIndex request param.
In a test-case with a rndis gadget running and sending a malformed packet to it like: dev.ctrl_transfer( 0x82, # bmRequestType 0x00, # bRequest 0x0000, # wValue 0x0001, # wIndex 0x00 # wLength ) it is possible to cause a crash:
[ 217.533022] dwc2 ff300000.usb: dwc2_hsotg_process_req_status: USB_REQ_GET_STATUS [ 217.559003] Unable to handle kernel read from unreadable memory at virtual address 0000000000000088 ... [ 218.313189] Call trace: [ 218.330217] ep_from_windex+0x3c/0x54 [ 218.348565] usb_gadget_giveback_request+0x10/0x20 [ 218.368056] dwc2_hsotg_complete_request+0x144/0x184
This happens because ep_from_windex wants to compare the endpoint direction even if index_to_ep() didn't return an endpoint due to the direction not matching.
The fix is easy insofar that the actual direction check is already happening when calling index_to_ep() which will return NULL if there is no endpoint for the targeted direction, so the offending check can go away completely.
Fixes: c6f5c050e2a7 ("usb: dwc2: gadget: add bi-directional endpoint support") Cc: stable@vger.kernel.org Reported-by: Gerhard Klostermeier gerhard.klostermeier@syss.de Signed-off-by: Heiko Stuebner heiko.stuebner@theobroma-systems.com Link: https://lore.kernel.org/r/20210127103919.58215-1-heiko@sntech.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/dwc2/gadget.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-)
--- a/drivers/usb/dwc2/gadget.c +++ b/drivers/usb/dwc2/gadget.c @@ -1470,7 +1470,6 @@ static void dwc2_hsotg_complete_oursetup static struct dwc2_hsotg_ep *ep_from_windex(struct dwc2_hsotg *hsotg, u32 windex) { - struct dwc2_hsotg_ep *ep; int dir = (windex & USB_DIR_IN) ? 1 : 0; int idx = windex & 0x7F;
@@ -1480,12 +1479,7 @@ static struct dwc2_hsotg_ep *ep_from_win if (idx > hsotg->num_of_eps) return NULL;
- ep = index_to_ep(hsotg, idx, dir); - - if (idx && ep->dir_in != dir) - return NULL; - - return ep; + return index_to_ep(hsotg, idx, dir); }
/**