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

Patch-Comment

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);
}
/**
 
 

Recent Patches

About Us

Sed lacus. Donec lectus. Nullam pretium nibh ut turpis. Nam bibendum. In nulla tortor, elementum vel, tempor at, varius non, purus. Mauris vitae nisl nec metus placerat consectetuer.

Read More...