From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792607181; b=grEuqSPrz2bOwUGsBlMnwrTn/Qz7jbPtGpd5r80PEfhz+jPRTrSweT74aWnxQDon2X1D adl0XmzCGVcRcmwS9JI7pYNR9IYgsVOlWTTZ7C2JGh1R0SeAbiRAMdg1F1cg8x9tNAE6Q FrRCfwrTkeDBgNxDhRPdC7hSSN1pSuJVTafvq/ehMayXJNL3PWJd5sSUA0WfyLK4rcCXW qkpYS6FgpTw81jfs0u/uOD0dSTs7dZMuT101DKRAi3E8cpvBw3pExbQ+5kEGSqTchDChu l1frCmGYz6ovHYkYFbjwUhX4Er8P31/0BHWxHVW2aMsSIfOAjTblwmlIDEWel+jogHA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792607181; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=xiaRUTE0hkAKS4647zdvqKZw10zxKRk62kBAFhu7ETI=; b=xR1DLW9geywTewDf58qRadztj5sey7mrpcOz1akDsM+RhWrF5S4cYOBivqL+tJp8+JKh JOfKxbHjMKBKwyRH65zyL/jjIuYPVLIbWjSfMLR/wQiVhLqfFGVWWnMJH9zxKcF/6soxT 7nmqbnBy902dPv+k/ximo9KiusEwZ7fXurfNkfgysyRDTOhJjqEocPGgS4/LbnQYmnhub y9vytzd2J9xblbpt/9aPkLgXq9LZxWIZH0MnLZklibFeSgs0n1xeZnRBiOxvHkoHGMooV yvZMsb3xgVGmLmpk5GaVYase/Utt8VGW/e+x6UAymoXlgonHOPmpY5vQRPENlO6GFrw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=BqIQA72T; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3E1A7606A319 for ; Wed, 21 Oct 2026 18:26:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=BqIQA72T Received: by smtp.kernel.org (Postfix) with ESMTPSA id 240C31F000C5; Wed, 21 Oct 2026 18:26:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792607180; bh=xiaRUTE0hkAKS4647zdvqKZw10zxKRk62kBAFhu7ETI=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=BqIQA72TC27Um+qtsKCAHcBA1Lc7ELGyMcoW3VwVXnNCMuXgwXx4f69JWW4dskHry WJUs21rb2SNZvrgFUkGBTMeLx/XzUNbdufcneMpmN84TBj/iBFk81/BCIVQmtoBWXC 5W9Ezibq3dbvAh9VJRk7ILOvNZlgGif4bHhUCcEY= Date: Wed, 21 Oct 2026 20:26:12 +0200 From: Greg KH To: Alan Stern Cc: linux-usb@vger.kernel.org Subject: Re: Linux USB threat-model document Message-ID: <2026102125-guide-slam-e2be@gregkh> References: <2026021847-acclaim-coil-fe7a@gregkh> <862abc70-18ce-422c-bdf2-f02b984193c0@rowland.harvard.edu> <2026022617-disengage-spinning-c6bd@gregkh> <7480e993-b873-4ea4-ac6e-45bd22975f8a@rowland.harvard.edu> X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7480e993-b873-4ea4-ac6e-45bd22975f8a@rowland.harvard.edu> On Wed, Oct 21, 2026 at 12:53:03PM -0400, Alan Stern wrote: > On Thu, Feb 26, 2026 at 08:29:45PM -0800, Greg KH wrote: > > Given that I have to answer this type of question about every other week > > these days given the fuzzing reports we get sent to the > > security@kernel.org alias, I think I need to just write up a "here is > > the Linux USB threat model that we currently support" document to > > describe what the state is. > > > > We can then work from there, either agreeing that we need to "move" the > > level of interaction for which we trust / do not trust a device in the > > lifecycle of a USB device, or just be happy with where it currently is. > > > > That should work better with some groups that I know are working to do > > stuff to "harden" the USB device stack for some specific use cases, > > hopefully just using the existing user api that we have today that > > USBGuard uses, or possibly adding to that to handle some missing areas > > that we have not previously considered. > > Did you ever make any progress on writing up this document? No, been swamped by the exponental increase in stable and CVE work :( > Have these outside groups gotten anywhere, or identified anything that > the kernel should do differently? Yes, there was a presentation at the Plumbers conference in the Android track about this and what the Android people would like to see be done differently in order to make this into a more secure type of a system. The slides for that should be online somewhere and the developers there said they would be sending patches to the list for review "sometime" in the future. Right now I think they have a long way to go before that happens, but at least they are thinking about it. thanks, greg k-h