Re: [PATCH v2 3/4] seccomp: add a way to get a listener fd from ptrace

Oleg Nesterov
2018-05-17T15:41:47Z

again, I don't understand this code yet, but

On 05/17, Tycho Andersen wrote:
>
> +long seccomp_get_listener(struct task_struct *task,
> + unsigned long filter_off)
> +{
> + struct seccomp_filter *filter;
> + struct file *listener;
> + int fd;
> +
> + filter = get_nth_filter(task, filter_off);
> + if (IS_ERR(filter))
> + return PTR_ERR(filter);
> +
> + fd = get_unused_fd_flags(O_RDWR);
> + if (fd < 0) {
> + __put_seccomp_filter(filter);
> + return fd;
> + }
> +
> + listener = init_listener(task, task->seccomp.filter);
> + if (IS_ERR(listener)) {
> + put_unused_fd(fd);
> + return PTR_ERR(listener);

__put_seccomp_filter() ?

and since init_listener() does __get_seccomp_filter() on sucess, it is needed
uncondtitionally?

Oleg.