From e9f19071157e76312b0c3ae3d85d9649189c2963 Mon Sep 17 00:00:00 2001 From: Toby Gray Date: Thu, 2 Sep 2010 10:46:20 +0100 Subject: [PATCH] USB: cdc-acm: Fixing crash when ACM probing interfaces with no endpoint descriptors. commit 577045c0a76e34294f902a7d5d60e90b04d094d0 upstream. Certain USB devices, such as the Nokia X6 mobile phone, don't expose any endpoint descriptors on some of their interfaces. If the ACM driver is forced to probe all interfaces on a device the a NULL pointer dereference will occur when the ACM driver attempts to use the endpoint of the alternative settings. One way to get the ACM driver to probe all the interfaces is by using the /sys/bus/usb/drivers/cdc_acm/new_id interface. This patch checks that the endpoint pointer for the current alternate settings is non-NULL before using it. Signed-off-by: Toby Gray Cc: Oliver Neukum Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index fd3aec7280a0..e3017c46d5ec 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -971,7 +971,8 @@ static int acm_probe(struct usb_interface *intf, } if (!buflen) { - if (intf->cur_altsetting->endpoint->extralen && + if (intf->cur_altsetting->endpoint && + intf->cur_altsetting->endpoint->extralen && intf->cur_altsetting->endpoint->extra) { dev_dbg(&intf->dev, "Seeking extra descriptors on endpoint\n"); -- 2.39.5