Subject: Re: [PATCH 1/2] Fix a NULL-ptr-deref bug in ath6kl_usb_alloc_urb_from_pipe

From: Kalle Valo <[email-masked]>
Date: Wed, 4 Sep 2019 06:23:55 +0000 (UTC)

Hui Peng <[email-masked]> wrote:

> The `ar_usb` field of `ath6kl_usb_pipe_usb_pipe` objects
> are initialized to point to the containing `ath6kl_usb` object
> according to endpoint descriptors read from the device side, as shown
> below in `ath6kl_usb_setup_pipe_resources`:
> 
> for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
> 	endpoint = &iface_desc->endpoint[i].desc;
> 
> 	// get the address from endpoint descriptor
> 	pipe_num = ath6kl_usb_get_logical_pipe_num(ar_usb,
> 						endpoint->bEndpointAddress,
> 						&urbcount);
> 	......
> 	// select the pipe object
> 	pipe = &ar_usb->pipes[pipe_num];
> 
> 	// initialize the ar_usb field
> 	pipe->ar_usb = ar_usb;
> }
> 
> The driver assumes that the addresses reported in endpoint
> descriptors from device side  to be complete. If a device is
> malicious and does not report complete addresses, it may trigger
> NULL-ptr-deref `ath6kl_usb_alloc_urb_from_pipe` and
> `ath6kl_usb_free_urb_to_pipe`.
> 
> This patch fixes the bug by preventing potential NULL-ptr-deref
> (CVE-2019-15098).
> 
> Signed-off-by: Hui Peng <[email-masked]>
> Reported-by: Hui Peng <[email-masked]>
> Reported-by: Mathias Payer <[email-masked]>
> Reviewed-by: Greg Kroah-Hartman <[email-masked]>
> Signed-off-by: Kalle Valo <[email-masked]>

Patch applied to ath-next branch of ath.git, thanks.

39d170b3cb62 ath6kl: fix a NULL-ptr-deref bug in ath6kl_usb_alloc_urb_from_pipe()

-- 
https://patchwork.kernel.org/patch/11074655/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches