On Wed, 26 Jul 2006 13:18:15 +0400
Evgeniy Polyakov <[EMAIL PROTECTED]> wrote:

> +static int kevent_ctl_process(struct file *file, 
> +             struct kevent_user_control *ctl, void __user *arg)
> +{
> +     int err;
> +     struct kevent_user *u = file->private_data;
> +
> +     if (!u)
> +             return -EINVAL;
> +
> +     switch (ctl->cmd) {
> +             case KEVENT_CTL_ADD:
> +                     err = kevent_user_ctl_add(u, ctl, 
> +                                     arg+sizeof(struct kevent_user_control));
> +                     break;
> +             case KEVENT_CTL_REMOVE:
> +                     err = kevent_user_ctl_remove(u, ctl, 
> +                                     arg+sizeof(struct kevent_user_control));
> +                     break;
> +             case KEVENT_CTL_MODIFY:
> +                     err = kevent_user_ctl_modify(u, ctl, 
> +                                     arg+sizeof(struct kevent_user_control));
> +                     break;
> +             case KEVENT_CTL_WAIT:
> +                     err = kevent_user_wait(file, u, ctl, arg);
> +                     break;
> +             case KEVENT_CTL_INIT:
> +                     err = kevent_ctl_init();
> +             default:
> +                     err = -EINVAL;
> +                     break;
> +     }
> +
> +     return err;
> +}

Please indent the body of the switch one tabstop to the left.

> +asmlinkage long sys_kevent_ctl(int fd, void __user *arg)
> +{
> +     int err, fput_needed;
> +     struct kevent_user_control ctl;
> +     struct file *file;
> +
> +     if (copy_from_user(&ctl, arg, sizeof(struct kevent_user_control)))
> +             return -EINVAL;
> +
> +     if (ctl.cmd == KEVENT_CTL_INIT)
> +             return kevent_ctl_init();
> +
> +     file = fget_light(fd, &fput_needed);
> +     if (!file)
> +             return -ENODEV;
> +
> +     err = kevent_ctl_process(file, &ctl, arg);
> +
> +     fput_light(file, fput_needed);
> +     return err;
> +}

If the user passes this an fd which was obtained via means other than
kevent_ctl_init(), the kernel will explode.  Do

        if (file->f_fop != &kevent_user_fops)
                return -EINVAL;

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