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>
---
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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