On Tue, 2009-01-06 at 15:20 -0500, J. Bruce Fields wrote: > On Tue, Jan 06, 2009 at 02:02:29PM -0600, Serge E. Hallyn wrote: > > Quoting Matt Helsley (matthltc@xxxxxxxxxx): > > > We can often specify the UTS namespace to use when starting an RPC client. > > > However sometimes no UTS namespace is available (specifically during system > > > shutdown as the last NFS mount in a container is unmounted) so fall > > > back to the initial UTS namespace. > > > > So what happens if we take this patch and do nothing else? > > > > The only potential problem situation will be rpc requests > > made on behalf of a container in which the last task has > > exited, right? So let's say a container did an nfs mount > > and then exits, causing an nfs umount request. > > > > That umount request will now be sent with the wrong nodename. > > Does that actually cause problems, will the server use the > > nodename to try and determine the client sending the request? > > This is just the machine name in the auth_unix credential? The linux > server ignores that completely (for the purpose of auth_unix > authenication, it identifies clients only by source ip address). I > suspect other servers also ignore it, but I don't know. > > --b. I was wondering about this because I kept coming back to the question of how the server could trust the name the client supplies (seems it can't). This is very useful information -- it certainly suggests that this patch would be sufficient. Thanks! Cheers, -Matt Helsley > > > > thanks, > > -serge > > > > > Signed-off-by: Matt Helsley <matthltc@xxxxxxxxxx> > > > Cc: Cedric Le Goater <clg@xxxxxxxxxx> > > > Cc: Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx> > > > Cc: linux-nfs@xxxxxxxxxxxxxxx > > > Cc: Trond Myklebust <trond.myklebust@xxxxxxxxxx> > > > Cc: Chuck Lever <chuck.lever@xxxxxxxxxx> > > > Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx> > > > Cc: Linux Containers <containers@xxxxxxxxxxxxxx> > > > > > > --- > > > net/sunrpc/clnt.c | 7 +++++-- > > > 1 file changed, 5 insertions(+), 2 deletions(-) > > > > > > Index: linux-2.6.28/net/sunrpc/clnt.c > > > =================================================================== > > > --- linux-2.6.28.orig/net/sunrpc/clnt.c > > > +++ linux-2.6.28/net/sunrpc/clnt.c > > > @@ -128,6 +128,7 @@ static struct rpc_clnt * rpc_new_client( > > > struct rpc_version *version; > > > struct rpc_clnt *clnt = NULL; > > > struct rpc_auth *auth; > > > + struct new_utsname *uts_ns = init_utsname(); > > > int err; > > > size_t len; > > > > > > @@ -213,10 +214,12 @@ static struct rpc_clnt * rpc_new_client( > > > } > > > > > > /* save the nodename */ > > > - clnt->cl_nodelen = strlen(init_utsname()->nodename); > > > + if (current->nsproxy != NULL) > > > + uts_ns = utsname(); > > > + clnt->cl_nodelen = strlen(uts_ns->nodename); > > > if (clnt->cl_nodelen > UNX_MAXNODENAME) > > > clnt->cl_nodelen = UNX_MAXNODENAME; > > > - memcpy(clnt->cl_nodename, init_utsname()->nodename, clnt->cl_nodelen); > > > + memcpy(clnt->cl_nodename, uts_ns->nodename, clnt->cl_nodelen); > > > rpc_register_client(clnt); > > > return clnt; > > > > > > > > > -- > > > _______________________________________________ > > > Containers mailing list > > > Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx > > > https://lists.linux-foundation.org/mailman/listinfo/containers -- 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
