Commit 886e3b7f authored Sep 15, 2009 by J. Bruce Fields

nfsd4: fix null dereference creating nfsv4 callback client



On setting up the callback to the client, we attempt to use the same
authentication flavor the client did.  We find an rpc cred to use by
calling rpcauth_lookup_credcache(), which assumes that the given
authentication flavor has a credentials cache.  However, this is not
required to be true--in particular, auth_null does not use one.
Instead, we should call the auth's lookup_cred() method.

Without this, a client attempting to mount using nfsv4 and auth_null
triggers a null dereference.

Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

parent 4be36ca0

fs/nfsd/nfs4callback.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -437,6 +437,7 @@ 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
		@@ -444,8 +445,7 @@ 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->au_ops->lookup_cred(auth, &acred, RPCAUTH_LOOKUP_NEW);
		}

		void do_probe_callback(struct nfs4_client *clp)