[PATCH 3.16 170/305] usb: gadget: avoid exposing kernel stack

[Ben Hutchings]

3.16.37-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Heinrich Schuchardt <xypron.glpk@xxxxxx>

commit ffeee83aa0461992e8a99a59db2df31933e60362 upstream.

Function in_rq_cur copies random bytes from the stack.
Zero the memory instead.

Fixes: 132fcb460839 ("usb: gadget: Add Audio Class 2.0 Driver")
Signed-off-by: Heinrich Schuchardt <xypron.glpk@xxxxxx>
Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
[bwh: Backported to 3.16: adjust filename]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/usb/gadget/f_uac2.c | 1 +
 1 file changed, 1 insertion(+)

--- a/drivers/usb/gadget/f_uac2.c
+++ b/drivers/usb/gadget/f_uac2.c
@@ -1153,6 +1153,7 @@ in_rq_cur(struct usb_function *fn, const
 
 	if (control_selector == UAC2_CS_CONTROL_SAM_FREQ) {
 		struct cntrl_cur_lay3 c;
+		memset(&c, 0, sizeof(struct cntrl_cur_lay3));
 
 		if (entity_id == USB_IN_CLK_ID)
 			c.dCUR = p_srate;