How WebNFS Security Negotiation Works

The Solaris 8 release includes a new protocol that enables a WebNFS client to negotiate a selected security mechanism with a WebNFS server. The new protocol uses security negotiation multi-component lookup, which is an extension to the multi-component lookup that was used in earlier versions of the WebNFS protocol.

The WebNFS client initiates the process by making a regular multi–component lookup request by using the public file handle. Because the client has no knowledge of how the path is protected by the server, the default security mechanism is used. If the default security mechanism is not sufficient, the server replies with an AUTH_TOOWEAK error. This reply indicates that the default mechanism is not valid. The client needs to use a stronger default mechanism.

When the client receives the AUTH_TOOWEAK error, the client sends a request to the server to determine which security mechanisms are required. If the request succeeds, the server responds with an array of security mechanisms that are required for the specified path. Depending on the size of the array of security mechanisms, the client might have to make more requests to obtain the complete array. If the server does not support WebNFS security negotiation, the request fails.

After a successful request, the WebNFS client selects the first security mechanism from the array that the client supports. The client then issues a regular multi-component lookup request by using the selected security mechanism to acquire the file handle. All subsequent NFS requests are made by using the selected security mechanism and the file handle.

The NFS version 4 protocol is preferred over the WebNFS service. NFS version 4 fully integrates all the security negotiation that was added to the MOUNT protocol and the WebNFS service.