>From 54f9886454e9a28e8d943c1cef15df9c11555df7 Mon Sep 17 00:00:00 2001
From: JohnnyB <jboero@xxxxxxxxxxxxxxxxxxxxxxxx>
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 <boeroboy@xxxxxxxxx>
---
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
