On Mar 19, 2012, at 1:36 PM, J. Bruce Fields wrote: > On Mon, Mar 19, 2012 at 01:06:47PM -0400, Rick Macklem wrote: >> I wrote: >>> J. Bruce Fields wrote: >>>> On Mon, Mar 12, 2012 at 05:27:08PM -0400, J. Bruce Fields wrote: >>>>> On Mon, Mar 12, 2012 at 05:14:16PM -0400, Chuck Lever wrote: >>>>>> IMO, the server should do a comparison of the nfs_client_id4 >>>>>> strings, >>>>>> and nothing else. >>>>> >>>>> We're supposed to return CLID_INUSE when we see a setclientid from >>>>> a >>>>> "different" client using the same string, to keep clients from >>>>> doing >>>>> mischief with other clients' state (either maliciously or, as in >>>>> this >>>>> case, accidentally). >>>>> >>>>> "Different" here is defined as "not having the same principal". I >>>>> know >>>>> what that means in the krb5 case, but I'm less certain in the >>>>> auth_sys >>>>> case. >>>> >>>> Cc'ing the ietf list. Is it reasonable for a server to expect >>>> setclientid's to come from the same client IP address at least in >>>> the >>>> auth_sys case, or could that break multi-homed clients? >>>> >>> I think that even a dhcp lease renewal might result in a different >>> client >>> IP, if the client has been partitioned from the dhcp server for a >>> while. > > Yeah, but by that point the client's v4 lease is probably expired anyway > so the client's not likely to be bothered by the NFS4ERR_INUSE. > >>> I'm not convinced that different client IP# implies different client. >>> (Even "same ip# implies same client" might not be true, if the dhcp >>> server assigned the IP# to another machine while the client was >>> partitioned >>> from the dhcp server, I think? I haven't looked at current dhcp >>> implementations, but it seems conceivable to me.) >>> >> Oh, and what about the case of 2 clients that are sitting behind >> the same NAT gateway? (I think they'd both be seen as having the >> client host ip# of the gateway, but with different TCP connections >> on different client port#s.) > > Well, sure, but all I'm proposing here is returning NFS4ERR_INUSE in the > case where we get setclientid's with the same client-provided id. > There'd be no change of behavior in the case of multiple clients sharing > an IP (which is fine, of course). The migration draft proposes that clients use the same nfs_client_id4 string for all of a server's IP addresses. Would a server then be obliged to return NFS4ERR_CLID_IN_USE if a client attempts a SETCLIENTID with the same boot verifier and nfs_client_id4 on more than one IP address for the same server? IMO the server should not try to sort this situation out. >>> For AUTH_SYS, all the FreeBSD server does is expect the same uid#. > > Yeah, but that's probably usually the same between clients. -- Chuck Lever chuck[dot]lever[at]oracle[dot]com -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
