91 lines
2.1 KiB
C
91 lines
2.1 KiB
C
/**
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* Vulnerable kernel driver
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*
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* This module is vulnerable to OOB access and allows arbitrary code
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* execution.
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* An arbitrary offset can be passed from user space via the provided ioctl().
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* This offset is then used as an index for the 'ops' array to obtain the
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* function address to be executed.
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*
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*
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* Full article: https://cyseclabs.com/page?n=17012016
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*
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* Author: Vitaly Nikolenko
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* Email: vnik@cyseclabs.com
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**/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/fs.h>
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#include <linux/device.h>
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#include "drv.h"
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#define DEVICE_NAME "vulndrv"
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#define DEVICE_PATH "/dev/vulndrv"
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static int device_open(struct inode *, struct file *);
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static long device_ioctl(struct file *, unsigned int, unsigned long);
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static int device_release(struct inode *, struct file *f);
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static struct class *class;
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unsigned long *ops[3];
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static int major_no;
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static struct file_operations fops = {
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.open = device_open,
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.release = device_release,
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.unlocked_ioctl = device_ioctl
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};
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static int device_release(struct inode *i, struct file *f) {
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printk(KERN_INFO "device released!\n");
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return 0;
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}
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static int device_open(struct inode *i, struct file *f) {
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printk(KERN_INFO "device opened!\n");
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return 0;
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}
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static long device_ioctl(struct file *file, unsigned int cmd, unsigned long args) {
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struct drv_req *req;
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void (*fn)(void);
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switch(cmd) {
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case 0:
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req = (struct drv_req *)args;
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printk(KERN_INFO "size = %lx\n", req->offset);
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printk(KERN_INFO "fn is at %p\n", &ops[req->offset]);
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fn = &ops[req->offset];
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fn();
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break;
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default:
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break;
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}
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return 0;
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}
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static int m_init(void) {
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printk(KERN_INFO "addr(ops) = %p\n", &ops);
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major_no = register_chrdev(0, DEVICE_NAME, &fops);
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class = class_create(THIS_MODULE, DEVICE_NAME);
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device_create(class, NULL, MKDEV(major_no, 0), NULL, DEVICE_NAME);
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return 0;
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}
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static void m_exit(void) {
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device_destroy(class, MKDEV(major_no, 0));
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class_unregister(class);
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class_destroy(class);
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unregister_chrdev(major_no, DEVICE_NAME);
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printk(KERN_INFO "Driver unloaded\n");
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}
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module_init(m_init);
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module_exit(m_exit);
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MODULE_LICENSE("GPL");
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