netdev - Re: [PATCH] net/cdc_ncm: fix null pointer panic at usbnet_link

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20131029.223823.1852248673779937090.davem@davemloft.net>
Date:	Tue, 29 Oct 2013 22:38:23 -0400 (EDT)
From:	David Miller <davem@...emloft.net>
To:	changbinx.du@...el.com
Cc:	oliver@...kum.org, linux-usb@...r.kernel.org,
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] net/cdc_ncm: fix null pointer panic at
 usbnet_link_change

From: "Du, ChangbinX" <changbinx.du@...el.com>
Date: Tue, 29 Oct 2013 03:30:42 +0000

> In cdc_ncm_bind() function, it call cdc_ncm_bind_common() to setup usb.
> But cdc_ncm_bind_common() may meet error and cause usbnet_disconnect()
> be called which calls free_netdev(net). Thus usbnet structure(alloced
> with net_device structure) will be freed,too.
> So we cannot call usbnet_link_change() if cdc_ncm_bind_common() return
> error.

This is not the bug.

The problem is in cdc_ncm_bind_common().

It seems to leave dangling interface data pointers in some cases, and
then branches just to "error" so that they don't get cleared back out.

This bypasses the protection present in cdc_ncm_disconnect() meant to
avoid this problem.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html