nsproxy: support CLONE_NEWTIME with setns()
So far setns() was missing time namespace support. This was partially due
to it simply not being implemented but also because vdso_join_timens()
could still fail which made switching to multiple namespaces atomically
problematic. This is now fixed so support CLONE_NEWTIME with setns()
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: Andrei Vagin <avagin@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Dmitry Safonov <dima@arista.com>
Link: https://lore.kernel.org/r/20200706154912.3248030-4-christian.brauner@ubuntu.com
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index cd35663..12dd41b 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -262,8 +262,8 @@ void exit_task_namespaces(struct task_struct *p)
static int check_setns_flags(unsigned long flags)
{
if (!flags || (flags & ~(CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
- CLONE_NEWNET | CLONE_NEWUSER | CLONE_NEWPID |
- CLONE_NEWCGROUP)))
+ CLONE_NEWNET | CLONE_NEWTIME | CLONE_NEWUSER |
+ CLONE_NEWPID | CLONE_NEWCGROUP)))
return -EINVAL;
#ifndef CONFIG_USER_NS
@@ -290,6 +290,10 @@ static int check_setns_flags(unsigned long flags)
if (flags & CLONE_NEWNET)
return -EINVAL;
#endif
+#ifndef CONFIG_TIME_NS
+ if (flags & CLONE_NEWTIME)
+ return -EINVAL;
+#endif
return 0;
}
@@ -464,6 +468,14 @@ static int validate_nsset(struct nsset *nsset, struct pid *pid)
}
#endif
+#ifdef CONFIG_TIME_NS
+ if (flags & CLONE_NEWTIME) {
+ ret = validate_ns(nsset, &nsp->time_ns->ns);
+ if (ret)
+ goto out;
+ }
+#endif
+
out:
if (pid_ns)
put_pid_ns(pid_ns);
@@ -507,6 +519,11 @@ static void commit_nsset(struct nsset *nsset)
exit_sem(me);
#endif
+#ifdef CONFIG_TIME_NS
+ if (flags & CLONE_NEWTIME)
+ timens_commit(me, nsset->nsproxy->time_ns);
+#endif
+
/* transfer ownership */
switch_task_namespaces(me, nsset->nsproxy);
nsset->nsproxy = NULL;
diff --git a/kernel/time/namespace.c b/kernel/time/namespace.c
index aa7b90a..afc65e6 100644
--- a/kernel/time/namespace.c
+++ b/kernel/time/namespace.c
@@ -280,7 +280,7 @@ static void timens_put(struct ns_common *ns)
put_time_ns(to_time_ns(ns));
}
-static void timens_commit(struct task_struct *tsk, struct time_namespace *ns)
+void timens_commit(struct task_struct *tsk, struct time_namespace *ns)
{
timens_set_vvar_page(tsk, ns);
vdso_join_timens(tsk, ns);
@@ -298,9 +298,6 @@ static int timens_install(struct nsset *nsset, struct ns_common *new)
!ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN))
return -EPERM;
-
- timens_commit(current, ns);
-
get_time_ns(ns);
put_time_ns(nsproxy->time_ns);
nsproxy->time_ns = ns;
