802.11 Security

Kernel Configuration

In order to securely use a wireless network, you must start with a secure host configuration. At the heart of any secure host is a solid, well-planned kernel configuration. A secure kernel must be governed by the Principle of Least Privilege. The Principle of Least Privilege indicates that a user or system should only be given the minimum amount of privilege in order to achieve the desired tasks. This means that a kernel should be stripped of all unneeded configuration options. If you don’t have any SCSI devices, then you shouldn’t have any SCSI devices specified in your kernel configuration.

Wireless Kernel Configuration

In order to use wireless NICs, the kernel must be configured to support the networking card. The process of compiling a Linux kernel is outside the scope of this book. For more information on compiling a kernel, see /usr/src/linux-2.4/README on your Linux system or http://www.tldp.org/HOWTO/Kernel-HOWTO.html. Configure and compile a kernel with as few configurations options as possible. Once you have a bare-bones kernel for your machine, continue with the steps in the rest of this chapter.

There are many ways to configure a kernel. Whether you use make menuconfig, make xconfig, or simply make config, the changes are saved to a configuration file. This file is typically in /usr/src/linux-2.4/configs/kernel-[ver].config. The configuration options specified in this chapter are directives in that file. How they get written to the file is up to ...