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Linux Kernel Programming

You're reading from   Linux Kernel Programming A comprehensive guide to kernel internals, writing kernel modules, and kernel synchronization

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Product type Paperback
Published in Mar 2021
Publisher Packt
ISBN-13 9781789953435
Length 754 pages
Edition 1st Edition
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Author (1):
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Kaiwan N. Billimoria Kaiwan N. Billimoria
Author Profile Icon Kaiwan N. Billimoria
Kaiwan N. Billimoria
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Table of Contents (19) Chapters Close

Preface 1. Section 1: The Basics
2. Kernel Workspace Setup FREE CHAPTER 3. Building the 5.x Linux Kernel from Source - Part 1 4. Building the 5.x Linux Kernel from Source - Part 2 5. Writing Your First Kernel Module - LKMs Part 1 6. Writing Your First Kernel Module - LKMs Part 2 7. Section 2: Understanding and Working with the Kernel
8. Kernel Internals Essentials - Processes and Threads 9. Memory Management Internals - Essentials 10. Kernel Memory Allocation for Module Authors - Part 1 11. Kernel Memory Allocation for Module Authors - Part 2 12. The CPU Scheduler - Part 1 13. The CPU Scheduler - Part 2 14. Section 3: Delving Deeper
15. Kernel Synchronization - Part 1 16. Kernel Synchronization - Part 2 17. About Packt 18. Other Books You May Enjoy

Trying it out – triggering a UAF bug

To help you understand this better, we'll show an example via screenshots in this section. Implement the following steps:

  1. Firstly, ensure you enable the CONFIG_SLUB_DEBUG kernel config (it should be set to y; this is typically the case on distro kernels)
  2. Next, boot the system while including the kernel command-line slub_debug= directive (this turns on full SLUB debug; or you could pass a finer granularity variant such as slub_debug=FZPU (see the kernel documentation here for an explanation of each field: https://www.kernel.org/doc/Documentation/vm/slub.txt); as a demo, on my Fedora 31 guest VM, I passed the kernel command line as follows - the important thing here, the slub_debug=FZPU is highlighted in bold font:
$ cat /proc/cmdline
BOOT_IMAGE=(hd0,msdos1)/vmlinuz-5.4.0-llkd01 root=/dev/mapper/fedora_localhost--live-root ro resume=/dev/mapper/fedora_localhost--live-swap rd.lvm.lv=fedora_localhost-live...
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