From: Andrey Vagin <[email protected]> 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: Serge Hallyn <[email protected]> Signed-off-by: Andrei Vagin <[email protected]> Signed-off-by: Eric W. Biederman <[email protected]> (cherry picked from VZ8 commit a7306ed8d94af729ecef8b6e37506a1c6fc14788) https://jira.sw.ru/browse/PSBM-102357 Signed-off-by: Pavel Tikhomirov <[email protected]> --- fs/nsfs.c | 4 ++++ include/linux/proc_ns.h | 1 + include/uapi/linux/nsfs.h | 2 ++ kernel/pid_namespace.c | 19 +++++++++++++++++++ kernel/user_namespace.c | 1 + 5 files changed, 27 insertions(+) diff --git a/fs/nsfs.c b/fs/nsfs.c index c5ddecea66bc..20ae4f7d92e6 100644 --- a/fs/nsfs.c +++ b/fs/nsfs.c @@ -176,6 +176,10 @@ static long ns_ioctl(struct file *filp, unsigned int ioctl, switch (ioctl) { case NS_GET_USERNS: 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: return -ENOTTY; } diff --git a/include/linux/proc_ns.h b/include/linux/proc_ns.h index c860e681d595..a8645c5eb679 100644 --- a/include/linux/proc_ns.h +++ b/include/linux/proc_ns.h @@ -19,6 +19,7 @@ struct proc_ns_operations { void (*put)(struct ns_common *ns); int (*install)(struct nsproxy *nsproxy, 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; diff --git a/include/uapi/linux/nsfs.h b/include/uapi/linux/nsfs.h index 5cacd5c1b5d7..3af617230d1b 100644 --- a/include/uapi/linux/nsfs.h +++ b/include/uapi/linux/nsfs.h @@ -7,5 +7,7 @@ /* Returns a file descriptor that refers to an owning user namespace */ #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 */ diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c index 302b234f5b06..c5541caf7a09 100644 --- a/kernel/pid_namespace.c +++ b/kernel/pid_namespace.c @@ -397,6 +397,24 @@ static int pidns_install(struct nsproxy *nsproxy, struct ns_common *ns) 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) { return to_pid_ns(ns)->user_ns; @@ -409,6 +427,7 @@ const struct proc_ns_operations pidns_operations = { .put = pidns_put, .install = pidns_install, .owner = pidns_owner, + .get_parent = pidns_get_parent, }; static __init int pid_namespaces_init(void) diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index fc388fbfad3f..1c83e5eddbad 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -1109,6 +1109,7 @@ const struct proc_ns_operations userns_operations = { .put = userns_put, .install = userns_install, .owner = userns_owner, + .get_parent = ns_get_owner, }; static __init int user_namespaces_init(void) -- 2.24.1 _______________________________________________ Devel mailing list [email protected] https://lists.openvz.org/mailman/listinfo/devel
