function::set_kernel_char - Linux

Overview

The function::set_kernel_char command modifies the character device special file /dev/kmem to allow writing to kernel memory. This enables low-level debugging and kernel hacking operations.

Syntax

function::set_kernel_char [-w]

Options/Flags

• -w: Enable writing to kernel memory. This option is required for modifying kernel variables.

Examples

Enable writing to kernel memory:

sudo function::set_kernel_char -w

Modify a kernel variable:

echo 1 > /dev/kmem | dd of=/dev/kmem bs=1 seek=0x1000 count=1

This sets the console_loglevel variable to 1, enabling kernel debug messages.

Common Issues

Permission denied: Ensure you have root privileges to modify /dev/kmem.

Invalid address: Double-check the address you are trying to modify in kernel memory.

Integration

The function::set_kernel_char command can be used in conjunction with other tools for advanced debugging, such as:

• gdb: For debugging kernel code.
• memwatch: For monitoring kernel memory usage.

Related Commands

• dmesg: Displays kernel messages.
• kdb: Kernel debugger.
• psaux: View running processes.