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Commit a7306ed8 authored by Andrey Vagin's avatar Andrey Vagin Committed by Eric W. Biederman
Browse files

nsfs: add ioctl to get a parent namespace



Pid and user namepaces are hierarchical. There is no way to discover
parent-child relationships.

In a future we will use this interface to dump and restore nested
namespaces.

Acked-by: default avatarSerge Hallyn <serge@hallyn.com>
Signed-off-by: default avatarAndrei Vagin <avagin@openvz.org>
Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
parent 6786741d
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+4 −0
Original line number Original line Diff line number Diff line
@@ -171,6 +171,10 @@ static long ns_ioctl(struct file *filp, unsigned int ioctl,
	switch (ioctl) {
	switch (ioctl) {
	case NS_GET_USERNS:
	case NS_GET_USERNS:
		return open_related_ns(ns, ns_get_owner);
		return open_related_ns(ns, ns_get_owner);
	case NS_GET_PARENT:
		if (!ns->ops->get_parent)
			return -EINVAL;
		return open_related_ns(ns, ns->ops->get_parent);
	default:
	default:
		return -ENOTTY;
		return -ENOTTY;
	}
	}
+1 −0
Original line number Original line Diff line number Diff line
@@ -19,6 +19,7 @@ struct proc_ns_operations {
	void (*put)(struct ns_common *ns);
	void (*put)(struct ns_common *ns);
	int (*install)(struct nsproxy *nsproxy, struct ns_common *ns);
	int (*install)(struct nsproxy *nsproxy, struct ns_common *ns);
	struct user_namespace *(*owner)(struct ns_common *ns);
	struct user_namespace *(*owner)(struct ns_common *ns);
	struct ns_common *(*get_parent)(struct ns_common *ns);
};
};


extern const struct proc_ns_operations netns_operations;
extern const struct proc_ns_operations netns_operations;
+2 −0
Original line number Original line Diff line number Diff line
@@ -7,5 +7,7 @@


/* Returns a file descriptor that refers to an owning user namespace */
/* Returns a file descriptor that refers to an owning user namespace */
#define NS_GET_USERNS	_IO(NSIO, 0x1)
#define NS_GET_USERNS	_IO(NSIO, 0x1)
/* Returns a file descriptor that refers to a parent namespace */
#define NS_GET_PARENT	_IO(NSIO, 0x2)


#endif /* __LINUX_NSFS_H */
#endif /* __LINUX_NSFS_H */
+19 −0
Original line number Original line Diff line number Diff line
@@ -388,6 +388,24 @@ static int pidns_install(struct nsproxy *nsproxy, struct ns_common *ns)
	return 0;
	return 0;
}
}


static struct ns_common *pidns_get_parent(struct ns_common *ns)
{
	struct pid_namespace *active = task_active_pid_ns(current);
	struct pid_namespace *pid_ns, *p;

	/* See if the parent is in the current namespace */
	pid_ns = p = to_pid_ns(ns)->parent;
	for (;;) {
		if (!p)
			return ERR_PTR(-EPERM);
		if (p == active)
			break;
		p = p->parent;
	}

	return &get_pid_ns(pid_ns)->ns;
}

static struct user_namespace *pidns_owner(struct ns_common *ns)
static struct user_namespace *pidns_owner(struct ns_common *ns)
{
{
	return to_pid_ns(ns)->user_ns;
	return to_pid_ns(ns)->user_ns;
@@ -400,6 +418,7 @@ const struct proc_ns_operations pidns_operations = {
	.put		= pidns_put,
	.put		= pidns_put,
	.install	= pidns_install,
	.install	= pidns_install,
	.owner		= pidns_owner,
	.owner		= pidns_owner,
	.get_parent	= pidns_get_parent,
};
};


static __init int pid_namespaces_init(void)
static __init int pid_namespaces_init(void)
+1 −0
Original line number Original line Diff line number Diff line
@@ -1034,6 +1034,7 @@ const struct proc_ns_operations userns_operations = {
	.put		= userns_put,
	.put		= userns_put,
	.install	= userns_install,
	.install	= userns_install,
	.owner		= userns_owner,
	.owner		= userns_owner,
	.get_parent	= ns_get_owner,
};
};


static __init int user_namespaces_init(void)
static __init int user_namespaces_init(void)