From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oliver Neukum Subject: Re: [example PATCH - not for applying] exclude certain commands Date: Sat, 26 Apr 2003 10:24:37 +0200 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <200304261024.37470.oliver@neukum.org> References: Reply-To: oliver@neukum.name Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from Mail1.KONTENT.De ([81.88.34.36]:12732 "EHLO Mail1.KONTENT.De") by vger.kernel.org with ESMTP id S263129AbTDZIM3 (ORCPT ); Sat, 26 Apr 2003 04:12:29 -0400 In-Reply-To: Content-Disposition: inline List-Id: linux-scsi@vger.kernel.org To: Alan Stern Cc: Andries.Brouwer@cwi.nl, stelian@popies.net, James.Bottomley@steeleye.com, afafc@rnl.ist.utl.pt, Greg KH , linux-scsi@vger.kernel.org, USB development list , pwkpete@yahoo.com > Do you mean it makes user space drivers inferior to kernel drivers? I > don't see how. The LLDD would treat them both the same, doing a minimum > of modifications. You got to make up your mind :-) So the LLDD should filter in both cases? > If you mean that it would make user space drivers inferior to the way they > work now, then I agree. At least, they might be inferior in terms of > performance, since they would no longer have commands altered > automatically for their benefit. On the other hand, they would be > superior in terms of receiving a more transparent channel directly to the > device. For some people this is very important. For the larger part it's vastly important that exactly that doesn't happen. Eg. I want the user to have access to a device, but I don't want him to be able to crash the device. It's a multiuser system and others might want to use the device afterwards. We usually require root level to get a transparent channel to hardware. If filtering is marginal you need to use yet another demon to be checked for buffer overflows, etc. ... . > I think it won't really be a problem. A user-space driver _ought_ to be > prepared to cope with the quirks and special requirements of a particular > device. But can you depend on it? From an administration viewpoint you create a hole for a DoS attack. Regards Oliver