Security testing

From Linux NFS

There are mainely two way to see security on NFS :

• Security functionnalities and components : kerberos, spkm, lipkey ...
• Knowing if we can trust on NFSv4, with or without security components.

Each Security components (such as kerberos) should its own independant section. This section is on the second part : how can we be sure NFSv4 is secure. For now this page is mainely a reflexion around this subject.

As far as I know there is one generic attack from a remote machine to a server. It uses buffers overflow/underflow to set excecutable code on the stack.

Others attacks are not generics, each attack depend on the imagination of the cracker :

• to use a function in a different way the function was designed.
• to imitate the client / the server with a modified one.

In order to avoid securities hole we need :

• to be sure the size of each buffer is checked
• to list all NFS functions that could be used on a different way there was designed
• to be sure data sent by a modified client / server could not be used to access a server/client (for example : can anyone modifie delegated datas to create a problem on the server? )