On Mon, Sep 14, 2009 at 04:17:32PM -0400, Trond Myklebust wrote:
> On Mon, 2009-09-14 at 16:04 -0400, J. Bruce Fields wrote:
> > On Mon, Sep 14, 2009 at 08:23:37PM +0300, Benny Halevy wrote:
> > > Where exactly is the NULL deref?
> > >
> > > >
> > > > Note--that's fixed 7 patches later in fsd41: Refactor create_client(),
> > > > but I don't actually understand how yet.
> > >
> > > unconf's cl_flavor initialization was moved in the latter patch
> > > from nfsd4_setclientid to create_client so maybe this could
> > > be the culprit (though, assuming it is initialized to 0
> > > it will choosing implicitly authnull_ops in rpcauth_create()
> > > which _should_ work...)
> >
> > Oog, yes, turns out auth_null doesn't initialize the cred hashtable. So
> > also reproduceable by mounting with "mount -tnfs4 -osec=null", then
> > touching a file. So either we should be using some other interface, or
> > rpcauth_lookupcred should be checking au_credcache, or something.
>
> There shouldn't be a need for an auth_null hashtable. It isn't a
> credential...
Got it. Looking at the code: I guess rpcauth_lookup_credcache is really
meant to be used only by auth types implementing their own cred lookups.
Err, maybe I want the following?
Or add a "lookup_machine_cred" helper to auth.c. Or use the
auth_generic stuff?
--b.
diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 77a6d10..b91cc8e 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -450,6 +450,7 @@ static struct rpc_cred *lookup_cb_cred(struct nfs4_cb_conn *cb)
struct auth_cred acred = {
.machine_cred = 1
};
+ struct rpc_auth *auth = cb->cb_client->cl_auth;
/*
* Note in the gss case this doesn't actually have to wait for a
@@ -457,8 +458,7 @@ static struct rpc_cred *lookup_cb_cred(struct nfs4_cb_conn *cb)
* non-uptodate cred which the rpc state machine will fill in with
* a refresh_upcall later.
*/
- return rpcauth_lookup_credcache(cb->cb_client->cl_auth, &acred,
- RPCAUTH_LOOKUP_NEW);
+ return auth->lookup_cred(auth, &acred, RPCAUTH_LOOKUP_NEW);
}
void do_probe_callback(struct nfs4_client *clp)
--
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