>From 54f9886454e9a28e8d943c1cef15df9c11555df7 Mon Sep 17 00:00:00 2001 From: JohnnyB <[email protected]> Date: Thu, 12 Nov 2020 15:28:29 +0000 Subject: [PATCH] usb: core: Null deref in kernel with USB webcams.
Fixes: Ubuntu Launchpad bug 1827452 This is my first attempt at a kernel contribution so sorry if sloppy. There is some kind of race condition affecting Logitech webcams that crash USB with a null dereference. Affects raspberry pi devices as well as x86. No check on dev before dereference. Simple fix for issue experienced for months in both x86 and arm/rpi environments. Signed-off-by: John Boero <[email protected]> --- drivers/usb/core/usb.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c index d8756ffe513a..9b4ac4415f1a 100644 --- a/drivers/usb/core/usb.c +++ b/drivers/usb/core/usb.c @@ -272,13 +272,9 @@ EXPORT_SYMBOL_GPL(usb_find_alt_setting); struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev, unsigned ifnum) { - struct usb_host_config *config = NULL; + struct usb_host_config *config = dev->actconfig; int i; - if (!dev) - return NULL; - - config = dev->actconfig; if (!config) return NULL; for (i = 0; i < config->desc.bNumInterfaces; i++) -- 2.26.2
