Securing the Linux Kernel by patching even its smallest vulnerabilities is of high importance as these small things can cost a lot. One such area that is exploited regularly is a structure in read-write mode. According to my mentor Julia it is good to work on something small and focused but at the same time which is of high importance. And I totally agree with her because these small steps will make a huge impact to the Kernel security in long term. …

For every patch sent for a Linux kernel driver one needs to be sure that the .o file has been obtained after compiling the changed .c file. A driver can contain a mixture of files that are meant for different machine architectures like blackfin, arm, sparc, mips, x86 etc. It might happen that a .c file written for arm architecture might not compile on my machine which is based on a x86 architecture. To solve this problem and to send a patch for arm architecture based files from my machine, I need to cross compile the files for arm.

Whenever…

Pointers in C/C++ have always confused people as they can be used in many ways and these ways can go really crazy sometimes. Understanding this topic is a bit complex initially but once you get hold of it you will appreciate how beautifully the concept of pointers work in C and C++. Pointers can be one of the reasons why working in languages like Python and Java seems a bit odd initially. This happened in my case.

There can be pointers to const objects, const pointers, const pointers to const objects, pointer to pointer to a data type, const pointer…

As mentioned in my previous blog my internship with the Linux Kernel is focused on the ways to make the kernel more secure. Adding const annotation to the structures is one of the ways to achieve this.

Annotating a variable of any data type with ‘const’ implies that it becomes read only and cannot be modified anywhere again after getting initialized in the beginning.

Consider a simple example.c file.

static struct stu abc = {
        .one=1, 
        .two=2
};void func1 (void) 
{
        ...
        struct x *p;
        ...
        p->ops=&abc;
        ...
}void func2(void)
{
       ...
       process_mode(&abc)
       ...
}

Declaration of the…

My Outreachy internship with the Linux Kernel revolves around the ways to make the kernel more secure from attacks that involves overwriting the memory regions allocated to the kernel code. One of the ways to protect the kernel from an attack is to make different parts of the kernel read-only. I have been able to explore this topic with thorough guidance of my mentor Julia Lawall. She explained me how read-only data of the kernel works, how are they stored, how and when to use them. In this blog I will explain one of the ways to secure the kernel.

…

Before starting my story I would like to introduce myself. My name is Bhumika Goyal and I am a 4th year student of B.tech in Computer Science and Engineering. This November I got an excellent opportunity to work as an Outreachy intern for the Linux kernel. It’s really exciting to be a part of such wonderful Linux community where one gets to learn new things everyday.

Difference:

I often see people asking : What’s the difference between Linux and the Linux kernel? Well the difference is really interesting. When people generally refer to “Linux” they either mean the Linux kernel…