2018-03-20 18:44:18

by Heinrich Schuchardt

Subject: [PATCH v3 1/1] usb: musb: gadget: misplaced out of bounds check

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 <[email protected]>
---
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

2018-03-20 18:57:24

by Bin Liu

Subject: Re: [PATCH v3 1/1] usb: musb: gadget: misplaced out of bounds check

Hi,

On Tue, Mar 20, 2018 at 07:42:48PM +0100, Heinrich Schuchardt wrote:
> 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 <[email protected]>
> ---
> 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(-)


Applied. Thanks.

Regards,
-Bin.