Messages in this thread | | | Date | Sun, 06 Aug 2017 03:58:27 +1000 | From | Aleksa Sarai <> | Subject | Re: [PATCH] sched: debug: use task_pid_vnr in /proc/$pid/sched |
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On 2017-08-06 02:52, Aleksa Sarai wrote: > It appears as though the addition of the PID namespace did not update > the output code for /proc/$pid/sched, which made it trivial to figure > out whether a process was inside &init_pid_ns from userspace (making > container detection trivial[1]). This lead to situations such as: > > % unshare -pf head -n1 /proc/self/sched > head (10047, #threads: 1) > > Fix this by just using task_pid_vnr for the output of /proc/$pid/sched. > All of the other uses of task_pid_nr in kernel/sched/debug.c are from a > sysctl context and thus don't need to be namespaced. > > [1]: https://github.com/jessfraz/amicontained > > Cc: <stable@vger.kernel.org> > Cc: Jess Frazelle <acidburn@google.com> > Signed-off-by: Aleksa Sarai <asarai@suse.com> > --- > kernel/sched/debug.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c > index 4fa66de52bd6..a06acbe33e16 100644 > --- a/kernel/sched/debug.c > +++ b/kernel/sched/debug.c > @@ -876,7 +876,7 @@ void proc_sched_show_task(struct task_struct *p, > struct seq_file *m) > { > unsigned long nr_switches; > > - SEQ_printf(m, "%s (%d, #threads: %d)\n", p->comm, task_pid_nr(p), > + SEQ_printf(m, "%s (%d, #threads: %d)\n", p->comm, task_pid_vnr(p), > get_nr_threads(p)); > SEQ_printf(m, > "---------------------------------------------------------"
Added Eric to Cc.
-- Aleksa Sarai Software Engineer (Containers) SUSE Linux GmbH https://www.cyphar.com/
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