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Where is kernel loaded?
When a Linux system boot process starts after the Master Boot Record (MBR) step, GRUB is loaded. The kernel needs to be loaded into RAM to start the OS, but the kernel is situated on the hard disk ( /boot/vmlinuz ), and the hard disk is not yet mounted on / . Without mounting, no files can be accessed, even the kernel.
What does the kernel do at startup?
The startup function for the kernel (also called the swapper or process 0) establishes memory management (paging tables and memory paging), detects the type of CPU and any additional functionality such as floating point capabilities, and then switches to non-architecture specific Linux kernel functionality via a call …
How are kernel modules loaded into the kernel?
A kernel module is a program which can loaded into or unloaded from the kernel upon demand, without necessarily recompiling it (the kernel) or rebooting the system, and is intended to enhance the functionality of the kernel. In general software terms, modules are more or less like plugins to a software such as WordPress.
Can a rootkit use a loadable kernel module?
Many rootkits make use of LKMs in this way. Note that on most operating systems modules do not help privilege elevation in any way, as elevated privilege is required to load a LKM; they merely make it easier for the attacker to hide the break-in. Linux allows disabling module loading via sysctl option /proc/sys/kernel/modules_disabled.
What is the role of the kernel in an operating system?
It basically manages operations of memory and CPU time. It is core component of an operating system. Kernel acts as a bridge between applications and data processing performed at hardware level using inter-process communication and system calls.
When does a process make a request to the kernel?
When a process makes requests of the kernel, it is called a system call. Kernel designs differ in how they manage these system calls and resources. A monolithic kernel runs all the operating system instructions in the same address space for speed. A microkernel runs most processes in user space, for modularity.