xhci: Fix Panther point NULL pointer deref at full-speed re-enumeration

In the Linux kernel, the following vulnerability has been resolved:

xhci: Fix Panther point NULL pointer deref at full-speed re-enumeration

re-enumerating full-speed devices after a failed address device command

can trigger a NULL pointer dereference.

Full-speed devices may need to reconfigure the endpoint 0 Max Packet Size

value during enumeration. Usb core calls usb_ep0_reinit() in this case,

which ends up calling xhci_configure_endpoint().

On Panther point xHC the xhci_configure_endpoint() function will

additionally check and reserve bandwidth in software. Other hosts do

this in hardware

If xHC address device command fails then a new xhci_virt_device structure

is allocated as part of re-enabling the slot, but the bandwidth table

pointers are not set up properly here.

This triggers the NULL pointer dereference the next time usb_ep0_reinit()

is called and xhci_configure_endpoint() tries to check and reserve

bandwidth

[46710.713538] usb 3-1: new full-speed USB device number 5 using xhci_hcd

[46710.713699] usb 3-1: Device not responding to setup address.

[46710.917684] usb 3-1: Device not responding to setup address.

[46711.125536] usb 3-1: device not accepting address 5, error -71

[46711.125594] BUG: kernel NULL pointer dereference, address: 0000000000000008

[46711.125600] #PF: supervisor read access in kernel mode

[46711.125603] #PF: error_code(0x0000) - not-present page

[46711.125606] PGD 0 P4D 0

[46711.125610] Oops: Oops: 0000 [#1] PREEMPT SMP PTI

[46711.125615] CPU: 1 PID: 25760 Comm: kworker/1:2 Not tainted 6.10.3_2 #1

[46711.125620] Hardware name: Gigabyte Technology Co., Ltd.

[46711.125623] Workqueue: usb_hub_wq hub_event [usbcore]

[46711.125668] RIP: 0010:xhci_reserve_bandwidth (drivers/usb/host/xhci.c

Fix this by making sure bandwidth table pointers are set up correctly

after a failed address device command, and additionally by avoiding

checking for bandwidth in cases like this where no actual endpoints are

added or removed, i.e. only context for default control endpoint 0 is

evaluated.