can: gs_usb: gs_usb_open/close(): fix memory leak

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: can: gs_usb: gs_usb_open/close(): fix memory leak The gs_usb driver appears to suffer from a malady common to many USB CAN adapter drivers in that it performs usb_alloc_coherent() to allocate a number of USB request blocks (URBs) for RX, and then later relies on usb_kill_anchored_urbs() 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 esd_usb2 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 usb_free_coherent(). Since the RX URBs were allocated in the gs_can_open(), we remove them in gs_can_close() rather than in the disconnect function as was done in esd_usb2. For more information, see the 928150fad41b ("can: esd_usb2: fix memory leak").

References

• https://git.kernel.org/stable/c/339fa9f80d3b94177a7a459c6d115d3b56007d5a
• https://git.kernel.org/stable/c/c1d806bc29ff7ffe0e2a023583c8720ed96cb0b0
• https://git.kernel.org/stable/c/d91492638b054f4a359621ef216242be5973ed6b
• https://git.kernel.org/stable/c/6f655b5e13fa4b27e915b6c209ac0da74fd75963
• https://git.kernel.org/stable/c/d0b8e223998866b3e7b2895927d4e9689b0a80d8
• https://git.kernel.org/stable/c/0e60230bc64355c80abe993d1719fdb318094e20
• https://git.kernel.org/stable/c/ffb6cc6601ec7c8fa963dcf76025df4a02f2cf5c
• https://git.kernel.org/stable/c/2bda24ef95c0311ab93bda00db40486acf30bd0a