usb: dwc2: Fix endpoint direction check in ep_from_windex

A patch from »usb: dwc2: Fix endpoint direction check in ep_from_windex« in state Mainline for linux-kernel

From: Heiko Stuebner <heiko.stuebner@...> Date: Mon, 25 Jan 2021 16:41:37 +0100

Commit-Message

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") Reported-by: Gerhard Klostermeier <gerhard.klostermeier@...> Signed-off-by: Heiko Stuebner <heiko.stuebner@...> Cc: stable@vger.kernel.org

Patch-Comment

changes in v3: - added Reported-by tag changes in v2: - remove unused struct dwc2_hsotg_ep *ep; drivers/usb/dwc2/gadget.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-)

Statistics

  • 1 lines added
  • 7 lines removed

Changes

-------------------------- drivers/usb/dwc2/gadget.c ---------------------------
index 0a0d11151cfb..ad4c94366dad 100644
@@ -1543,7 +1543,6 @@ static void dwc2_hsotg_complete_oursetup(struct usb_ep *ep,
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;
@@ -1553,12 +1552,7 @@ static struct dwc2_hsotg_ep *ep_from_windex(struct dwc2_hsotg *hsotg,
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);
}
/**
 
 

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