On Wed, Aug 28, 2013 at 10:30 PM, Jiri Kosina <jkosina@xxxxxxx> wrote:
> From: Kees Cook <keescook@xxxxxxxxxxxx>
>
> This driver must validate the availability of the HID output report and
> its size before it can write LED states via buzz_set_leds(). This stops
> a heap overflow that is possible if a device provides a malicious HID
> output report:
>
> [ 108.171280] usb 1-1: New USB device found, idVendor=054c, idProduct=0002
> ...
> [ 117.507877] BUG kmalloc-192 (Not tainted): Redzone overwritten
>
> CVE-2013-2890
>
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxx
> ---
> drivers/hid/hid-sony.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/hid/hid-sony.c b/drivers/hid/hid-sony.c
> index 87fbe29..b987926 100644
> --- a/drivers/hid/hid-sony.c
> +++ b/drivers/hid/hid-sony.c
> @@ -537,6 +537,10 @@ static int buzz_init(struct hid_device *hdev)
> drv_data = hid_get_drvdata(hdev);
> BUG_ON(!(drv_data->quirks & BUZZ_CONTROLLER));
>
> + /* Validate expected report characteristics. */
> + if (!hid_validate_report(hdev, HID_OUTPUT_REPORT, 0, 1, 7))
I don't have access to the device anymore, but I still kept the report
descriptors (this is the interesting part):
0xa1, 0x02, // Collection (Logical) 60
0x75, 0x08, // Report Size (8) 62
0x95, 0x07, // Report Count (7) 64
0x46, 0xff, 0x00, // Physical Maximum (255) 66
0x26, 0xff, 0x00, // Logical Maximum (255) 69
0x09, 0x02, // Usage (Vendor Usage 2) 72
0x91, 0x02, // Output (Data,Var,Abs) 74
0xc0, // End Collection 76
So with the current implementation of hid_validate_report(), it works,
but if another Buzz controller show up at some point with extras
fields in this output report... we will be screwed. So please, amend
hid_validate_report(), or specifically test here that the LED output
report is 7 bytes.
Cheers,
Benjamin
> + return -ENODEV;
> +
> buzz = kzalloc(sizeof(*buzz), GFP_KERNEL);
> if (!buzz) {
> hid_err(hdev, "Insufficient memory, cannot allocate driver data\n");
>
> --
> Jiri Kosina
> SUSE Labs
> --
> To unsubscribe from this list: send the line "unsubscribe linux-input" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-input" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
