Grsecurity core

Grsecurity is a patch for the Linux kernel that adds additional security mechanisms to the Linux kernel. The key functionality of Grsecurity is to protect against memory spoofing attacks and to improve security policies for various components of a Linux system, such as network connections, file systems, IPC and others.

Grsecurity features

The main goal of Grsecurity is to protect against vulnerabilities designed to compromise system memory and take control of a computer or server. For this purpose, Grsecurity includes mechanisms that protect the kernel and user processes from attacks such as:

1. Buffer overflow protection.
2. Protection against vulnerabilities in the kernel.
3. Cache and file system protection.
4. Separation (via RBAC) into access areas for physically separate processes.

Grsecurity also provides tools to assess system security, such as security logging, system file inspection, and vulnerability testing.

However, implementing Grsecurity can require additional time and effort at each stage of development and deployment, which requires a certain level of security expertise.

Kernel has several important security features:

1. Grsecurity. Grsecurity patches the kernel to protect it from a variety of known hacking and compromise techniques. This patch protects against spoofing and exploits, and can disable or block access to vulnerable kernel features.
2. Access sharing. Grsecurity has a mechanism called RBAC (Role-Based Access Control) that will split access to areas between physically separate processes. RBAC allows you to assign roles with an access rights engine that can be defined on a per-user or per-group basis.
3. Kernel Security. Grsecurity protects the kernel from corruption and unauthorized modification by controlling memory and system resources at a lower kernel level. This makes it impossible to execute code or modify memory in the kernel without authorization.
4. Control of exported characters. Grsecurity controls which kernel functions can be called from kernel modules or from the user space environment. Users can customize which symbols can be exported and used in kernel modules.
5. Network Stack and TCP/IP Stack Protection. Grsecurity adds additional network stack and TCP/IP stack protection to the Linux kernel, which provides protection against DDoS attacks, as well as protection against other such attacks.
6. Journaling Control. Grsecurity controls which users can view higher-level logs that can be accessed that may contain sensitive information.

Grsecurity provides improved control over system security and provides more advanced security mechanisms than the standard Linux kernel.

Kernel benefits

Grsecurity benefits include:

1. Significantly improved system security because Grsecurity provides additional layers of protection that are not included in the standard Linux kernel.
2. Protection against most known types of attacks, including buffer overflow attacks, memory attacks, task scheduling attacks, and many others.
3. Ability to customize Grsecurity to meet individual user needs and requirements, which increases optimal performance.
4. High performance compared to other security systems, allowing Grsecurity to be used on production machines without slowing them down.
5. Grsecurity support comes as an optional package, making its use more flexible than other security systems that can be built into the Linux kernel.
6. Grsecurity provides a "backward compatibility" mode that allows programs designed for the standard Linux kernel to run on a system with a secure kernel.

Next, let's look at the disadvantages of the modified kernel.

Kernel disadvantages

Despite its many advantages, Grsecurity has some disadvantages as well:

1. Limited support - Grsecurity is not included in the standard repositories of Linux distributions, and is supported by a limited number of developers. This means that users may find it difficult to install and support.
2. High level of complexity - Configuring Grsecurity can be a complex and time-consuming process. Some options severely limit the functionality of the Linux kernel, so users should have a good understanding of how these options will affect their systems.
3. Restricted functionality - some Linux features may be blocked or restricted in Grsecurity to ensure security. This can sometimes lead to performance degradation or compatibility issues with other programs.
4. Proprietary status - Grsecurity is released under a license that does not guarantee free access to the source code. This can be a problem for those who prefer to use only free software.
5. Some routers with the specified name may simply not be suitable. You need to choose the right one for your particular model.

How do I install the kernel? This question will be addressed next.

Installation process

Installing Grsecurity is a bit more complicated than installing a regular Linux kernel and requires some knowledge and experience in kernel building. Here are the general steps to install Grsecurity:

• Download the Linux kernel and Grsecurity source code from the official website.
• Unzip the archives to a separate directory, such as /usr/src.
• Configure the Linux kernel with make menuconfig, selecting the appropriate Grsecurity settings.
• Compile and install the Linux kernel using the make command.
• Configure the system to use the new Linux kernel in the /boot/grub/grub.cfg file.
• Reboot the system and verify that the new Linux kernel starts without errors.

Note that the Grsecurity installation process may vary depending on your Linux distribution and Linux kernel version. Therefore, it is better to read the official documentation of Grsecurity and your Linux distribution before installation to avoid problems and errors.