The Linux Kernel Module Programming Guide 3.2 Pdf Download
Prepare the System for Building LKMsThe system must be prepared to build kernel code, and to do this you must have the Linux headers installed on your device. On a typical Linux desktop machine you can use your package manager to locate the correct package to install. For example, under 64-bit Debian you can use: molloyd@DebianJessieVM:$ sudo apt-get update molloyd@DebianJessieVM:$ apt-cache search linux-headers-$(uname -r) linux-headers-3.16.0-4-amd64 - Header files for Linux 3.16.0-4-amd64 molloyd@DebianJessieVM:$ sudo apt-get install linux-headers-3.16.0-4-amd64 molloyd@DebianJessieVM:$ cd /usr/src/linux-headers-3.16.0-4-amd64/ molloyd@DebianJessieVM:/usr/src/linux-headers-3.16.0-4-amd64$ ls arch include Makefile Module.symvers scripts
the linux kernel module programming guide 3.2 pdf download
You can then check that the headers have installed correctly: molloyd@beaglebone:/tmp$ cd /usr/src/linux-headers-3.8.13-bone70/ molloyd@beaglebone:/usr/src/linux-headers-3.8.13-bone70$ ls Documentation Module.symvers crypto fs ipc mm scripts tools Kconfig arch drivers include kernel net security usr Makefile block firmware init lib samples sound virtUnder the 3.8.13-bone47 Debian distribution for the BeagleBone, you may have to perform an unusual step of creating an empty file timex.h (i.e., touch timex.h) in the directory /usr/src/linux-headers-3.8.13-bone47/arch/arm/ include/mach. This step is not necessary under the bone70 build.
This module can now be loaded using the kernel module tools as follows: molloyd@beaglebone:/exploringBB/extras/kernel/hello$ ls -l *.ko -rw-r--r-- 1 molloyd molloyd 4219 Apr 4 23:27 hello.ko molloyd@beaglebone:/exploringBB/extras/kernel/hello$ sudo insmod hello.ko molloyd@beaglebone:/exploringBB/extras/kernel/hello$ lsmod Module Size Used by hello 972 0 g_multi 50407 2 libcomposite 15028 1 g_multi omap_rng 4062 0 mt7601Usta 639170 0
This is how I downloaded the Linux headers: 1) add this to the top of the file /etc/apt/sources.list deb [arch=armhf] -ee.net/repos/debian wheezy main 2) apt-get update 3) apt-get upgrade 4)reboot 5)uname -r gave me 4.1.15-bone18 6)apt-get install linux-headers-4.1.15-bone18 7) The new linux headers are now in /usr/src/
Thank you, highly informative article. I have been running the example on 4.1.15-ti-r43 without any issue. The linux kernel headers were already available from the sd card image downloaded from beaglebone.org (dpkg -l grep Linux-headers).
This article is really great, I am a student interested in exploit development (Windows and Linux). I really want to learn how to develop kernel modules (rootkits) like a professional. Can you give me some references to resourceful materials please.
If Secure Boot is enabled, the UEFI operating system boot loaders, the Red Hat Enterprise Linux kernel, and all kernel modules have to be signed with a private key and authenticated with the corresponding public key. If they are not signed and authenticated, the system will not be allowed to finish the booting process.
In RHEL 8, the validity dates of the key pair do not matter. The key does not expire, but it is recommended for good security practices that the kernel module be signed within the validity period of its signing key. However, the sign-file utility will not warn you and the key will be usable regardless of the validity dates.
Enrolling a MOK key requires manual interaction by a user at the UEFI system console on each target system. Nevertheless, the MOK facility provides a convenient method for testing newly generated key pairs and testing kernel modules signed with them.
To facilitate authentication of your kernel module on your systems, consider requesting your system vendor to incorporate your public key into the UEFI Secure Boot key database in their factory firmware image.
The appended signature is not contained in an ELF image section and is not a formal part of the ELF image. Therefore, utilities such as readelf will not be able to display the signature on your kernel module.
In RHEL 8, the validity dates of the key pair matter. The key does not expire, but the kernel module must be signed within the validity period of its signing key. The sign-file utility will not warn you of this. For example, a key that is only valid in 2019 can be used to authenticate a kernel module signed in 2019 with that key. However, users cannot use that key to sign a kernel module in 2020.
The Linux Programmer's Guide is meant to do what the name implies -- It is to help Linux programmers understand the peculiarities of Linux. By its nature, this also means that it should be useful when porting programs from other operating systems to Linux. Therefore, this guide must describe the system calls and the major kernel changes which have effects on older programs like serial I/O and networking.
Linux is deployed on a wide variety of computing systems, such as embedded devices, mobile devices (including its use in the Android operating system), personal computers, servers, mainframes, and supercomputers. It can be tailored for specific architectures and for several usage scenarios using a family of simple commands (that is, without the need of manually editing its source code before compilation); privileged users can also fine-tune kernel parameters at runtime. Most of the Linux kernel code is written using the GNU extensions of GCC to the standard C programming language and with the use of architecture-specific instructions (ISA) in limited parts of the kernel. This produces a highly optimized executable (vmlinux) with respect to utilization of memory space and task execution times.
Starting with version 2.0, Linux is configurable for selecting specific hardware targets and for enabling architecture-specific features and optimizations. The make *config family of commands of kbuild are used to enable and configure thousands of options for building ad hoc kernel executables (vmlinux) and loadable modules.
Version 2.6.0 was released on 17 December 2003. The development for 2.6.x changed further towards including new features throughout the duration of the series. Among the changes that have been made in the 2.6 series are: integration of µClinux into the mainline kernel sources, PAE support, support for several new lines of CPUs, integration of Advanced Linux Sound Architecture (ALSA) into the mainline kernel sources, support for up to 232 users (up from 216), support for up to 229 process IDs (64-bit only, 32-bit arches still limited to 215), substantially increased the number of device types and the number of devices of each type, improved 64-bit support, support for file systems which support file sizes of up to 16 terabytes, in-kernel preemption, support for the Native POSIX Thread Library (NPTL), User-mode Linux integration into the mainline kernel sources, SELinux integration into the mainline kernel sources, InfiniBand support, and considerably more.
In 2005 the stable team was formed as a response to the lack of a kernel tree where people could work on bug fixes, and it would keep updating stable versions. In February 2008 the linux-next tree was created to serve as a place where patches aimed to be merged during the next development cycle gathered. Several subsystem maintainers also adopted the suffix -next for trees containing code which they mean to submit for inclusion in the next release cycle. As of January 2014[update], the in-development version of Linux is held in an unstable branch named linux-next.
Linux is a monolithic kernel with a modular design (e.g., it can insert and remove loadable kernel modules at runtime), supporting most features once only available in closed source kernels of non-free operating systems. The rest of the article makes use of the UNIX and Unix-like operating systems convention on the official manual pages. The numbers that follow the name of commands, interfaces, and other features, have the purpose of specifying the section (i.e., the type of the OS' component or feature) they belong to (e.g., execve(2) refers to a system call, while exec(3) refers to a userspace library wrapper). The following list and the subsequent sections describe a non-comprehensive overview of Linux architectural design and of some of its noteworthy features.
Unlike standard monolithic kernels, device drivers are easily configured as modules, and loaded or unloaded while the system is running and can also be pre-empted under certain conditions in order to handle hardware interrupts correctly and to better support symmetric multiprocessing. By choice, Linux has no stable device driver application binary interface.
Loadable kernel modules (LKMs), by design, cannot rely on a stable ABI. Therefore, they must always be recompiled whenever a new kernel executable is installed in a system, otherwise they will not be loaded. In-tree drivers that are configured to become an integral part of the kernel executable (vmlinux) are statically linked by the building process.
There are several kernel internal APIs utilized between the different subsystems. Some are available only within the kernel subsystems, while a somewhat limited set of in-kernel symbols (i.e., variables, data structures, and functions) is exposed also to dynamically loadable modules (e.g., device drivers loaded on demand) whether they're exported with the EXPORT_SYMBOL() and EXPORT_SYMBOL_GPL() macros (the latter reserved to modules released under a GPL-compatible license).
The Linux developers chose not to maintain a stable in-kernel ABI. Modules compiled for a specific version of the kernel cannot be loaded into another version without being recompiled, assuming that the in-kernel API has remained the same at the source level; otherwise, the module code must also be modified accordingly.