Linux Kernel Lab

LAB 1: Basic Linux Kernel Module Development

1. basic module_init, module_exit usage
2. module parameters
3. read-only proc file
4. read-writable proc file

LAB 2: Scheduling

Add scheduling counter by modifying the kernel and recompile it

1. add counter variable in struct task_struct in include/linux/sched.h
2. initialize the counter (set to 0) in kernel_clone() in kernel/fork.c
3. increase the counter by 1 in activate_task() in kernel/sched/core.c
4. create a entry in tgid_base_stuff[] in fs/proc/base.c

See https://nickchen120235.github.io/2021/04/22/linux-kernel-scheduling.html for more details

LAB 3: Memory Management

Three memory management-related functionalities implemented for both x86 and aarch64 architectures

• listvma: print all virtual addresses of all processes in the format of start-addr end-addr permission
• findpage addr: print the corresponding physical address of virtual address addr. If no such translation exists, print translation not found
• writeval addr val: try to write val to addr

See https://nickchen120235.github.io/2021/05/18/linux-kernel-memory-management.html for more details

LAB 4: File System

Modify romfs implementation to accomplish the following functionalities

• hide a file: modify romfs_readdir
• encrypt a file: modify romfs_readpage
• change the permission of a file: modify romfs_lookup

Final Project: Linux System Call Hooking

Two methods for hooking

• modify sys_call_table
• ftrace
• bonus: use kprobe to find unexported kallsyms_lookup_name