stack overflow

["Breno" <brenosp@brasilsec.com.br>]

Hi ... this is my idea to check a stack overflow. What do you think ?


#define STACK_LIMIT (1024*8192)/PAGE_SIZE

int check_stack_overflow(struct task_struct *tsk)
{

    unsigned long stack_size,stack_addr,stack_ptr;
    int i;

         if(tsk->mm != NULL)
         {
                  stack_addr = tsk->mm->start_stack;

                  stack_ptr = tsk->thread.esp;

                  for(i=0; i < stack_ptr; i++)
                  stack_addr++;

                  stack_size = (stack_addr - stack_ptr)/PAGE_SIZE;

                  if(stack_size > ( STACK_LIMIT - 1))
                  {
                               printk(KERN_CRIT"Process %s : pid %d -
                                Can cause stack
overflow\n",tsk->comm,tsk->pid);
                               return 0;
                  }
         }
return 0;
}

att,
Breno