Programming

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/elf.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/binfmts.h>

#define PRINT(x) printk(KERN_INFO x "\n")
#define BSIGN_SIGTYPE 0x80736967    /* ((0x80 << 24)|('s' << 16)|('i' << 8)|'g') */


void readElf(struct elfhdr *elf_Head, Elf32_Shdr *elf_Section) {
    int i = 0;
    char *test;
    // Find Signature
    while(i < elf_Head->e_shnum && 
        elf_Section[i].sh_type != BSIGN_SIGTYPE) {
        printk(KERN_INFO "Sec: %d / %x -- BSIGN_SIGTYPE", i,  elf_Section[i].sh_type);
        i++;
    }
    if(i < elf_Head->e_shnum) {
        PRINT("Signatur gefunden");
        printk(KERN_INFO "Name: und Type:\n %x \n %x", elf_Section[i].sh_name,
            elf_Section[i].sh_type);
        printk(KERN_INFO "%s\n", test);
            return;
    }

    PRINT("NIX GEFUNDEN");
}

void openFile(void) {
    char *buf;
    int cnt, tmp;
    unsigned long off;
    struct elfhdr elfH;
    Elf32_Shdr *elfSec;
    struct file *fp;
    fp = filp_open("/home/chris/Test/test", O_RDONLY, 0);
    
    if(fp == (void *)0L) {
        PRINT("FILE NICHT DA");
        return;
    }

    if(fp->f_dentry == (void *)0L) {
        PRINT("F_DENTRY NICHT DA");
        return;
    }
    
    if(!fp->f_dentry->d_name.name) {
        PRINT("F_DENTRY NICHT DA");
        return;
    }
    
    printk(KERN_INFO "FILENAME: %s\n", fp->f_dentry->d_name.name);
    
    if(!(buf = kmalloc(BINPRM_BUF_SIZE, GFP_KERNEL))) {
        PRINT("KMALLOC");
        return;
    }

    tmp = kernel_read(fp, 0, buf, BINPRM_BUF_SIZE);
    elfH = *((struct elfhdr *) buf);
    printk(KERN_INFO "kernel read: %d \n", tmp);

    cnt = elfH.e_shnum * sizeof(Elf32_Shdr);
    if(!(elfSec = (Elf32_Shdr *) kmalloc(cnt, GFP_KERNEL))) {
        PRINT("KMALLOC2");
        kfree(buf);
        return;
    }

    readElf(&elfH, elfSec);
    kfree(elfSec);
}
    
static int __init testIntro(void) {
    printk(KERN_INFO "elfStart\n");
    openFile();
    return 0;
}

static void __exit testOutro(void) {
    printk(KERN_INFO "Closing down\n");
}

module_init(testIntro);
module_exit(testOutro);

$ head -n1 /proc/self/maps
08048000-08050000 r-xp 00000000 08:23 98602      /bin/head
$

void openFile(void) {
    struct file *fp;
    fp = filp_open("/home/chris/Test/testt", O_RDONLY, 0);

    if(fp == (void *)0L) {
        PRINT("FILE NICHT DA");
        return;
    }
    PRINT("TEST");
    if(fp->f_dentry == (void *)0L) {
        PRINT("F_DENTRY NICHT DA");
        return;
    }
    printk(KERN_INFO "FILENAME: %s\n", fp->f_dentry->d_name.name);
}