kernel-module

问题 I am developing Linux kernel module that communicate with user space program. This module waits for a message which is being sent from user space in order to print it in kernel mode. This is the module : #include <linux/init.h> #include <linux/module.h> #include <linux/fs.h> #include <linux/device.h> #include <linux/kernel.h> #include <linux/uaccess.h> MODULE_LICENSE("GPL"); MODULE_AUTHOR("Gaston"); MODULE_DESCRIPTION("A simple Linux char driver"); MODULE_VERSION("0.1"); #define MAX 256

问题 For a PoC (context), I’m trying to build a kernel module as a position independent executable. Currently, I compile my module using mcmodel=small -fpie -mno-red-zone -mnosse to my Makefile ( /lib/modules/$(uname -r)fixed/build/Makefile ) and then I resolve my symbols by parsing /proc/kallsyms and patching my binary using ld ’s option --defsym symbol=address But this is not satisfactory. I get a rip-relative addressing but no got/plt. Below an example of function in the generated module before

问题 insmod / rmmod doesn't recognize the arguments. Even insmod without any argument also gets executed. It looks like only command is recognized by the system. Through insmod command kernel module can be inserted dynamically but when I do insmod testStub.ko , nothing is happening. Neither do I see my module in lsmod result nor any printk messages that I have written in my testStub.c , in dmesg . lsmod / modprobe -l also don't show any output. lsmod command is supposed to show all running modules

问题 I'm unable to build a kernel module due to a missing .h file. I'm building the module on Ubuntu 14.04. This is the make file I use: $ cat Makefile obj-m += my_module.o all: make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules clean: make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean And this is the output of 'make': $ make make -C /lib/modules/3.13.0-34-generic/build M=/home/user/location modules make[1]: Entering directory `/usr/src/linux-headers-3.13.0-34-generic' CC [M]

问题 How can filter and/or display the name of the interface the packet has arrived from in the Kernel space ? More specifcally I want the name of the interfacen e.g eth0, wlan1 etc to be printed out in the kernel. Secondly how can I filter packets only from a specific interface e.g eth0 only? 回答1: In the hook function, there is parameters const struct net_device *in and const struct net_device *out . You can print it by: printk(KERN_INFO "%s\n", out->name); or: printk(KERN_INFO "%s\n", in->name);

问题 The following will create a file in user space but how can I create a directory? struct file *filp = filp_open("/home/myuser/Desktop/newfile", O_CREAT, S_IRWXU); 回答1: The best way I know how is to use: mkdir("your/directory", 0700); David Heffernan's comment shows the specifics. Edit: This page will show you the different mode parameters you can give for your directory and what they do. http://osdir.com/ml/linux.c-programming/2002-06/msg00069.html 回答2: Just set O_DIRECTORY in filp_open flags.

问题 I was learning some basics of kernel modules and threads. And so i tried to make a example module and test it. Now, it loads successfully. Module code: #include <linux/module.h> #include <linux/kernel.h> #include <linux/kthread.h> #include <linux/delay.h> #include <linux/version.h> static struct task_struct *thread_st; // Function called by thread static int thread_fun(void *unused) { allow_signal(SIGKILL); while(!kthread_should_stop()) { printk(KERN_INFO "Thread Running\n"); ssleep(5); if

问题 I've written a little linux kernel module, to see, how nowadays implement kernel function hijacking. https://pastebin.com/99YJFnaq #include <linux/module.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/string.h> #include <linux/syscalls.h> #include <linux/version.h> #include <linux/unistd.h> #include <linux/time.h> #include <linux/preempt.h> #include <asm/uaccess.h> #include <asm/paravirt.h> #include <asm-generic/bug.h> #include <asm/segment.h>

问题 (Linux 4.4) I am trying to get a kernel module to send information to a user process over a Generic Netlink. It seems that the message is not successfully received by the user process - the nlmsg_unicast function returns with -111. Here is what I know: The kernel module successfully registers a Generic Netlink family - it prints a message in the syslog indicating the (autogenerated) family ID (which is always 26). The user process successfully discovers the family ID (26). The user process

问题 I'm a bit confused by the variables available inside the Kernel. How would I go about iterating over all modules inside my own kernel module? I found modules being used in the kernel code. Can I do something along the lines of struct module *mod; list_for_each_entry(mod, &modules, list) { printk(KERN_INFO "%s\n", mod->name); } 回答1: There is no direct way for iterate over list of modules. Head of the module's list is modules variable, which is statically defined in kernel/module.c, so it is