librecmc-gitorious/target/linux/generic/patches-3.8/008-hso-Fix-stack-corruption-on-some-architectures.patch

From e75dc677ff8d06ffa61bef6fee436227ae5440c6 Mon Sep 17 00:00:00 2001
From: Daniel Gimpelevich <daniel@gimpelevich.san-francisco.ca.us>
Date: Wed, 21 Aug 2013 01:43:19 -0700
Subject: [PATCH 2/2] hso: Fix stack corruption on some architectures

As Sergei Shtylyov explained in the #mipslinux IRC channel:
[Mon 2013-08-19 12:28:21 PM PDT] <headless> guys, are you sure it's not "DMA off stack" case?
[Mon 2013-08-19 12:28:35 PM PDT] <headless> it's a known stack corruptor on non-coherent arches
[Mon 2013-08-19 12:31:48 PM PDT] <DonkeyHotei> headless: for usb/ehci?
[Mon 2013-08-19 12:34:11 PM PDT] <DonkeyHotei> headless: explain
[Mon 2013-08-19 12:35:38 PM PDT] <headless> usb_control_msg() (or other such func) should not use buffer on stack. DMA from/to stack is prohibited
[Mon 2013-08-19 12:35:58 PM PDT] <headless> and EHCI uses DMA on control xfers (as well as all the others)

Signed-off-by: Daniel Gimpelevich <daniel@gimpelevich.san-francisco.ca.us>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/net/usb/hso.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c
@@ -2838,13 +2838,16 @@ exit:
 static int hso_get_config_data(struct usb_interface *interface)
 {
 	struct usb_device *usbdev = interface_to_usbdev(interface);
-	u8 config_data[17];
+	u8 *config_data = kmalloc(17, GFP_KERNEL);
 	u32 if_num = interface->altsetting->desc.bInterfaceNumber;
 	s32 result;
 
+	if (!config_data)
+		return -ENOMEM;
 	if (usb_control_msg(usbdev, usb_rcvctrlpipe(usbdev, 0),
 			    0x86, 0xC0, 0, 0, config_data, 17,
 			    USB_CTRL_SET_TIMEOUT) != 0x11) {
+		kfree(config_data);
 		return -EIO;
 	}
 
@@ -2895,6 +2898,7 @@ static int hso_get_config_data(struct us
 	if (config_data[16] & 0x1)
 		result |= HSO_INFO_CRC_BUG;
 
+	kfree(config_data);
 	return result;
 }