2013-08-21 08:43:27

by Daniel Gimpelevich

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 <[email protected]>
---
drivers/net/usb/hso.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c
index 5fb36ed..86292e6 100644
--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c
@@ -2816,13 +2816,16 @@ 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;
}

@@ -2873,6 +2876,7 @@ static int hso_get_config_data(struct usb_interface *interface)
if (config_data[16] & 0x1)
result |= HSO_INFO_CRC_BUG;

+ kfree(config_data);
return result;
}

--
1.7.9.5

2013-08-21 16:24:49

by Greg Kroah-Hartman

Subject: Re: [PATCH 2/2] hso: Fix stack corruption on some architectures

On Wed, Aug 21, 2013 at 01:43:19AM -0700, Daniel Gimpelevich wrote:
> 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 <[email protected]>

Acked-by: Greg Kroah-Hartman <[email protected]>

2013-08-22 03:48:22

by David Miller

Subject: Re: [PATCH 2/2] hso: Fix stack corruption on some architectures

From: Greg KH <[email protected]>
Date: Wed, 21 Aug 2013 09:24:47 -0700

> On Wed, Aug 21, 2013 at 01:43:19AM -0700, Daniel Gimpelevich wrote:
>> 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 <[email protected]>
>
> Acked-by: Greg Kroah-Hartman <[email protected]>

Applied.