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Date:   Wed, 23 Nov 2022 16:40:33 +0100
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Subject: Re: [PATCH] USB: disable all RNDIS protocol drivers
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org
Cc:     "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, Kalle Valo <kvalo@kernel.org>,
        Oleksij Rempel <linux@rempel-privat.de>,
        =?UTF-8?Q?Maciej_=c5=bbenczykowski?= <maze@google.com>,
        Neil Armstrong <neil.armstrong@linaro.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Andrzej Pietrasiewicz <andrzejtp2010@gmail.com>,
        Jacopo Mondi <jacopo@jmondi.org>,
        =?UTF-8?Q?=c5=81ukasz_Stelmach?= <l.stelmach@samsung.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        linux-usb@vger.kernel.org, netdev@vger.kernel.org,
        linux-wireless@vger.kernel.org,
        Ilja Van Sprundel <ivansprundel@ioactive.com>,
        Joseph Tartaro <joseph.tartaro@ioactive.com>
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From:   Nicolas Cavallari <nicolas.cavallari@green-communications.fr>
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On 23/11/2022 13:46, Greg Kroah-Hartman wrote:
> The Microsoft RNDIS protocol is, as designed, insecure and vulnerable on
> any system that uses it with untrusted hosts or devices.  Because the
> protocol is impossible to make secure, just disable all rndis drivers to
> prevent anyone from using them again.
> 
> Windows only needed this for XP and newer systems, Windows systems older
> than that can use the normal USB class protocols instead, which do not
> have these problems.
> 
> Android has had this disabled for many years so there should not be any
> real systems that still need this.

I kind of disagree here. I have seen plenty of android devices that only 
support rndis for connection sharing, including my android 11 phone 
released in Q3 2020. I suspect the qualcomm's BSP still enable it by 
default.

There are also probably cellular dongles that uses rndis by default. 
Maybe ask the ModemManager people ?

I'm also curious if reimplementing it in userspace would solve the 
security problem.