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#include <asm/uaccess.h>
#include <linux/cdev.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kdev_t.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/list.h>
static char devname[] = "killuid";
static char modname[] = "killuid.ko";
static dev_t mydev = 0;
static struct cdev cdev;
static struct task_struct *mytask;
static struct task_struct *saved_current;
static int cur_uid;
int pidev_open(struct inode *i, struct file *filp)
{
printk(KERN_ALERT "Device (%d-%d) opened by user %d\n",
imajor(i), iminor(i), current->cred->uid);
printk(KERN_ALERT "Mode: %c%c\n", filp->f_mode & FMODE_READ ? 'R' : '-',
filp->f_mode & FMODE_WRITE ? 'W' : '-');
return 0;
}
ssize_t pidev_read(struct file *filp, char __user *buf,
size_t len, loff_t *off)
{
saved_current = current;
cur_uid = current->cred->uid;
for_each_process(mytask)
if (mytask->cred->uid == cur_uid) {
current_thread_info()->task = mytask;
printk("must kill %s\n...", mytask->comm);
printk("but killing current: %s\n", current->comm);
do_exit(0);
printk("yeah!\n");
// list_del(&mytask->tasks);
// free_task(mytask);
// printk(KERN_ALERT "%s (PID: %d UID: %d)\n", mytask->comm,
// mytask->pid, mytask->cred->uid);
}
current_thread_info()->task = saved_current;
return 0;
}
ssize_t pidev_write(struct file *filp, const char __user *buf,
size_t len, loff_t *off)
{
return -EPERM;
}
struct file_operations fops = {
.owner = THIS_MODULE,
.open = pidev_open,
.read = pidev_read,
.write = pidev_write,
};
static int __init killuid_init(void)
{
int err;
printk(KERN_ALERT "%s loaded by %s (%d)\n",
modname, current->comm, current->pid);
if ((err = alloc_chrdev_region(&mydev, 0, 1, devname)))
printk(KERN_ALERT "ERROR in alloc_chrdev_region: %d\n", err);
else
printk(KERN_ALERT "%s successfully registered with %d %d numbers\n",
devname, MAJOR(mydev), MINOR(mydev));
cdev_init(&cdev, &fops);
cdev.owner = THIS_MODULE;
if ((err = cdev_add(&cdev, mydev, 1)))
printk(KERN_ALERT "ERROR in cdev_add: %d\n", err);
return 0;
}
static void __exit killuid_exit(void)
{
unregister_chrdev_region(mydev, 1);
cdev_del(&cdev);
printk(KERN_ALERT "%s unloaded\n", modname);
}
module_init(killuid_init);
module_exit(killuid_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Guillermo Ramos");
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