CVE-2022-49661

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

can: gsusb: gsusb_open/close(): fix memory leak

The gsusb driver appears to suffer from a malady common to many USB CAN adapter drivers in that it performs usballoccoherent() to allocate a number of USB request blocks (URBs) for RX, and then later relies on usbkillanchoredurbs() to free them, but this doesn't actually free them. As a result, this may be leaking DMA memory that's been used by the driver.

This commit is an adaptation of the techniques found in the esdusb2 driver where a similar design pattern led to a memory leak. It explicitly frees the RX URBs and their DMA memory via a call to usbfreecoherent(). Since the RX URBs were allocated in the gscanopen(), we remove them in gscanclose() rather than in the disconnect function as was done in esdusb2.

For more information, see the 928150fad41b ("can: esd_usb2: fix memory leak").