On Friday, August 11, 2017, Jason Gerecke <killert...@gmail.com> wrote:
> The USB protocol allows devices to have multiple "configurations" that
> the OS can switch between. A an "unconfigured" state is also possible,
> especially when the device is first connected. If '__wacom_is_usb_parent'
> comes across an unconfigured USB device, the 'config' variable will
> be NULL. We need to add a check for this state before attempting a
> dereference.
>
> Fixes: 38c795d ("backport: HID: wacom: Improve generic name generation")
> Fixes: bb55947 ("HID: wacom: Improve generic name generation")
> Signed-off-by: Jason Gerecke <jason.gere...@wacom.com <javascript:;>>
The patch makes sense to me. It is
Reviewed-by: Ping Cheng <ping.ch...@wavom.com>
Cheers,
Ping
---
> Changes from v1:
> * Apply fix to 3.17 tree
> * Add proper "Fixes" annotations
>
> 3.17/wacom_sys.c | 2 +-
> 4.5/wacom_sys.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/3.17/wacom_sys.c b/3.17/wacom_sys.c
> index 9fccf59..2996d0d 100644
> --- a/3.17/wacom_sys.c
> +++ b/3.17/wacom_sys.c
> @@ -29,7 +29,7 @@ static int __wacom_is_usb_parent(struct usb_device
> *usbdev, void *ptr)
> struct usb_host_config *config = usbdev->actconfig;
> int i;
>
> - for (i = 0; i < config->desc.bNumInterfaces; i++) {
> + for (i = 0; config && i < config->desc.bNumInterfaces; i++) {
> if (&config->interface[i]->dev == parent)
> return 1;
> }
> diff --git a/4.5/wacom_sys.c b/4.5/wacom_sys.c
> index cfe5fa8..3a65174 100644
> --- a/4.5/wacom_sys.c
> +++ b/4.5/wacom_sys.c
> @@ -30,7 +30,7 @@ static int __wacom_is_usb_parent(struct usb_device
> *usbdev, void *ptr)
> struct usb_host_config *config = usbdev->actconfig;
> int i;
>
> - for (i = 0; i < config->desc.bNumInterfaces; i++) {
> + for (i = 0; config && i < config->desc.bNumInterfaces; i++) {
> if (&config->interface[i]->dev == parent)
> return 1;
> }
> --
> 2.13.4
>
>
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