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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: ISCSI: User authentication vs. Machine Authentication for iSCSIJim, I'm not sure the problem you mentioned is specific to iSCSI as I have seen a user-level Fibre Channel driver in action. The issue here is that the notion of user is an operating system abstraction and has no meaning in domains in which the OS has no administrative control (such as a SAN). Extending the notion of an user outside the domain of an OS requires primitives current SAN technology does not support (yet!) Prasenjit Sarkar Research Staff Member IBM Almaden Research San Jose Jim Hafner/Almaden To: ips@ece.cmu.edu /IBM@IBMUS cc: Sent by: Subject: RE: ISCSI: User authentication vs. Machine Authentication for iSCSI owner-ips@ece. cmu.edu 08/29/2001 03:00 PM Bill, I think I understand your question, so here's a remark. I think a problem that creeps in to the iSCSI space (that doesn't exist in essentially every other existing SCSI stack) is that a user can write an application that acts like an iSCSI initiator and never ever go through the OS stack. (I've written an iSCSI initiator in Java that doesn't ever use the host stack at all, just the standard network interfaces). So, I could easily have multiple iSCSI Initiators running (even in user space) on the same machine. At that point, I may want user level security. If I didn't understand your question, I'll shut up (on this topic :-{)) Jim Hafner "Bill Strahm" <bill@sanera.net>@ece.cmu.edu on 08/29/2001 02:23:20 pm Sent by: owner-ips@ece.cmu.edu To: <mbakke@cisco.com> cc: "Ips@Ece. Cmu. Edu" <ips@ece.cmu.edu> Subject: RE: ISCSI: User authentication vs. Machine Authentication for iSCSI I am not sure that helped. Again, the model of a Tape drive... The user does not own the tape drive, the operating system owns the tape drive, when I (as a user) wants to use the tape drive, I ask the operating system, it grants me access, and I go on. In fact from a purely SCSI level, I do not believe there is any concept of a user at all, the Operating system on the device provides the concept of a user through the OS abstraction layer. The problem that I am having is that I do not see how I can make user security work through the OS abstraction. And if the OS HAS to know about the multiple users, I now have to trust the OS as well, which means that effectively I have one user on the machine anyway... Bill -----Original Message----- From: mbakke@cisco.com [mailto:mbakke@cisco.com] Sent: Wednesday, August 29, 2001 2:06 PM To: Bill Strahm Cc: Ips@Ece. Cmu. Edu Subject: Re: ISCSI: User authentication vs. Machine Authentication for iSCSI Bill Strahm wrote: > > I have been fighting with this problem since I left LA. > > I am not aware of any usage scenarios today where block devices are owned by > the user rather than the machine. I will conceed that in many instances the > first thing the system does is assign the resource to a use (tape, scanner, > etc.) but the machine still owns the resource and can in fact remove it out > from under the user... > > I am not to certain how I could build a trusted iSCSI environment where one > user would have no knowledge about what was happening with other users in a > malicious environment (especially where a system was participating in the > exposure of resourses). Examples of this include things like co-located Web > hosting where a single user scans process memory looking for 1Kbit of random > data, and when finding it attempts to determine if that is the private key > of a user sharing the resource. > > The reason I am bringing this up, is I am not sure trying to define security > above the machine level makes any sense for iSCSI. Aren't most SCSI devices > owned by the Operating System not the User and partitioned out by the > Operating System to the users ? If this is the case many of our > authentication methods simplify to simple IKE identities. > > Bill Bill- As you pointed out, there is a case where just using IKE with an iSCSI AuthMethod of "none" is valid. That case is where: - There a one-to-one correspondence between an initiator and an operating system - IPsec is being used for all iSCSI traffic - The customer is willing to deploy public key certificates on the client side (for each initiator) as well as on the devices If all of the above are true, iSCSI can certainly use an AuthMethod of none, and be done with it. However, - There are cases (David Black brought up some tape applications) where more than one initiator might exist on an operating system - IPsec is not likely to be used for a large percentage of iSCSI traffic any time soon - When IPsec is used, many customers will have an easier time with the familiar model of authenticating the server "machine" but using a dummy certificate for the client. If any of the above are true, iSCSI-level of authentication is required. Hope this helps, Mark
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