Endpoint Administration Guide for UNIX › Protecting Files and Programs › Kernel Modules Load and Unload Protection

Kernel Modules Load and Unload Protection

A kernel module is a component of the UNIX operating system that you can load to extend the running kernel, and unload when no longer required. This adds flexibility, letting you load functionality as required, without wasting memory resources that would otherwise be required to cover all possible expected functionality in the base kernel.

You can disable and enable kernel module protection in CA Access Control. If you enable kernel module protection, CA Access Control intercepts the system calls that load and unload a kernel module, and then checks the requested access against the associated record in the database, which is a record of class KMODULE. When access is requested for a kernel module record, CA Access Control, the requested access is either "load" or "unload".

On all non-Linux systems, the name of the KMODULE record must match the name of the kernel module file (not the full path). This is because the name of the module is the same as the name of the file. On Linux, the name of KMODULE record needs to match only the name of the kernel module, which, may be different from the actual file name. Changing the file name on Linux does not change the module name which Linux uses and the KMODULE record remains valid.

If you enable file path checking on kernel module loads and the requested access is load, CA Access Control performs the following additional checks:

• The filepath property in the KMODULE record holds only valid absolute file paths.
• The files in the path name filepath have modules that match the KMODULE record name.
• The kernel module matches the KMODULE properties (filepath for non-Linux systems, signature for Linux systems).

  Note: CA Access Control produces a unique signature for kernel module file on Linux systems, and inserts this as the value of the signature property in the kernel module record. CA Access Control checks the signature on each access. You do not need to enter the signature yourself, because CA Access Control calculates and inserts it automatically. However you can do so using the seretrust utility.

More information:

Enable and Disable File Path Checking on Kernel Module Loads

seretrust Utility—Generate Commands to Retrust Programs and Secure Files