From bcac25a58bfc6bd79191ac5d7afb49bea96da8c9 Mon Sep 17 00:00:00 2001 From: Andrey Vagin Date: Tue, 6 Sep 2016 00:47:13 -0700 Subject: kernel: add a helper to get an owning user namespace for a namespace Return -EPERM if an owning user namespace is outside of a process current user namespace. v2: In a first version ns_get_owner returned ENOENT for init_user_ns. This special cases was removed from this version. There is nothing outside of init_user_ns, so we can return EPERM. v3: rename ns->get_owner() to ns->owner(). get_* usually means that it grabs a reference. Acked-by: Serge Hallyn Signed-off-by: Andrei Vagin Signed-off-by: Eric W. Biederman --- kernel/pid_namespace.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'kernel/pid_namespace.c') diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c index a65ba137fd15..c02d744225e1 100644 --- a/kernel/pid_namespace.c +++ b/kernel/pid_namespace.c @@ -388,12 +388,18 @@ static int pidns_install(struct nsproxy *nsproxy, struct ns_common *ns) return 0; } +static struct user_namespace *pidns_owner(struct ns_common *ns) +{ + return to_pid_ns(ns)->user_ns; +} + const struct proc_ns_operations pidns_operations = { .name = "pid", .type = CLONE_NEWPID, .get = pidns_get, .put = pidns_put, .install = pidns_install, + .owner = pidns_owner, }; static __init int pid_namespaces_init(void) -- cgit v1.2.1 From a7306ed8d94af729ecef8b6e37506a1c6fc14788 Mon Sep 17 00:00:00 2001 From: Andrey Vagin Date: Tue, 6 Sep 2016 00:47:15 -0700 Subject: 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: Serge Hallyn Signed-off-by: Andrei Vagin Signed-off-by: Eric W. Biederman --- kernel/pid_namespace.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'kernel/pid_namespace.c') diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c index c02d744225e1..4fa2d56a936c 100644 --- a/kernel/pid_namespace.c +++ b/kernel/pid_namespace.c @@ -388,6 +388,24 @@ 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; @@ -400,6 +418,7 @@ 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) -- cgit v1.2.1