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finit_module

Intro

finit_module - load a kernel module from a file descriptor.

Description

The finit_module() system call allows for loading and initializing a kernel module using a file descriptor that points to the binary image of the module. This contrasts with init_module(), which directly uses a pointer to the binary image. By utilizing a file descriptor, finit_module() can effectively offer a safer means to load kernel modules, particularly in certain contexts where direct memory access is restricted or unsafe.

Kernel modules serve as an essential mechanism to dynamically extend kernel functionalities without restarting the system, encompassing capabilities like device drivers, filesystems, and various protocols.

Arguments

  • fd:int[K] - File descriptor corresponding to the binary image of the module.
  • param_values:const char *[U] - A string indicating module parameters, facilitating customization of the module's behavior. Parameters are generally denoted as "param1=value1 param2=value2".
  • flags:int[K] - Flags indicating how the module is to be loaded:
    • O_TRACE - flag to trace module
    • O_DEBUG - debug flag
    • O_ASYNC - asynchronous initialization
    • O_EXCL - exclusive module initializing

Available Tags

  • K - Originated from kernel-space.
  • U - Originated from user space.
  • TOCTOU - Vulnerable to TOCTOU (time of check, time of use).
  • OPT - Optional argument - might not always be available (passed with null value).

Hooks

sys_finit_module

Type

Tracepoint (through sys_enter).

Purpose

To observe and document the invocation of the finit_module() system call, capturing specifics about the module being loaded and its associated parameters.

Example Use Case

In security-sensitive scenarios, tracking the loading of kernel modules through file descriptors can be pivotal to detect unauthorized or anomalous behaviors, ensuring the integrity of the kernel environment.

Issues

Introduction of malicious or defective kernel modules can introduce significant security threats or system instabilities. Rigorous validation and inspection of kernel modules before loading are paramount.

  • init_module() - Load a kernel module using a memory pointer.
  • delete_module() - Remove an already loaded kernel module.

This document was automatically generated by OpenAI and reviewed by a Human.