usb: r8a66597: Fix a possible concurrency use-after-free bug in r8a66597_endpoint_disable()
commit c85400f886e3d41e69966470879f635a2b50084c upstream. The function r8a66597_endpoint_disable() and r8a66597_urb_enqueue() may be concurrently executed. The two functions both access a possible shared variable "hep->hcpriv". This shared variable is freed by r8a66597_endpoint_disable() via the call path: r8a66597_endpoint_disable kfree(hep->hcpriv) (line 1995 in Linux-4.19) This variable is read by r8a66597_urb_enqueue() via the call path: r8a66597_urb_enqueue spin_lock_irqsave(&r8a66597->lock) init_pipe_info enable_r8a66597_pipe pipe = hep->hcpriv (line 802 in Linux-4.19) The read operation is protected by a spinlock, but the free operation is not protected by this spinlock, thus a concurrency use-after-free bug may occur. To fix this bug, the spin-lock and spin-unlock function calls in r8a66597_endpoint_disable() are moved to protect the free operation. Signed-off-by: NJia-Ju Bai <baijiaju1990@gmail.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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