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
This commit is contained in:
Christian Brauner
2020-07-06 17:49:11 +02:00
parent 5cfea9a106
commit 76c12881a3
3 changed files with 26 additions and 6 deletions

View File

@@ -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;