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* [PATCH v3 1/1] usb: musb: gadget: misplaced out of bounds check
@ 2018-03-20 18:42 ` Heinrich Schuchardt
  0 siblings, 0 replies; 4+ messages in thread
From: Heinrich Schuchardt @ 2018-03-20 18:42 UTC (permalink / raw)
  To: Bin Liu
  Cc: Sergei Shtylyov, Greg Kroah-Hartman, linux-usb, linux-kernel,
	Heinrich Schuchardt

musb->endpoints[] has array size MUSB_C_NUM_EPS.
We must check array bounds before accessing the array and not afterwards.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
---
v3
	Remove superfluous braces.
v2
	Only the 4 low bits of epnum are relevant for indexing.
---
 drivers/usb/musb/musb_gadget_ep0.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/musb/musb_gadget_ep0.c b/drivers/usb/musb/musb_gadget_ep0.c
index 18da4873e52e..91a5027b5c1f 100644
--- a/drivers/usb/musb/musb_gadget_ep0.c
+++ b/drivers/usb/musb/musb_gadget_ep0.c
@@ -89,15 +89,19 @@ static int service_tx_status_request(
 		}
 
 		is_in = epnum & USB_DIR_IN;
-		if (is_in) {
-			epnum &= 0x0f;
+		epnum &= 0x0f;
+		if (epnum >= MUSB_C_NUM_EPS) {
+			handled = -EINVAL;
+			break;
+		}
+
+		if (is_in)
 			ep = &musb->endpoints[epnum].ep_in;
-		} else {
+		else
 			ep = &musb->endpoints[epnum].ep_out;
-		}
 		regs = musb->endpoints[epnum].regs;
 
-		if (epnum >= MUSB_C_NUM_EPS || !ep->desc) {
+		if (!ep->desc) {
 			handled = -EINVAL;
 			break;
 		}
-- 
2.16.2


^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2018-03-20 18:56 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2018-03-20 18:42 [PATCH v3 1/1] usb: musb: gadget: misplaced out of bounds check Heinrich Schuchardt
2018-03-20 18:42 ` [v3,1/1] " Heinrich Schuchardt
2018-03-20 18:55 ` [PATCH v3 1/1] " Bin Liu
2018-03-20 18:55   ` [v3,1/1] " Bin Liu

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