On Mon, Jul 07, 2014 at 09:46:35PM +0200, Peter Zijlstra wrote:
> On Mon, Jul 07, 2014 at 07:00:40PM +0200, Jiri Olsa wrote:
> > diff --git a/kernel/trace/trace_event_perf.c
> > b/kernel/trace/trace_event_perf.c
> > index 5d12bb4..b44184b 100644
> > --- a/kernel/trace/trace_event_perf.c
> > +++ b/kernel/trace/trace_event_perf.c
> > @@ -24,6 +24,9 @@ static int total_ref_count;
> > static int perf_trace_event_perm(struct ftrace_event_call *tp_event,
> > struct perf_event *p_event)
> > {
> > + struct task_struct owner = p_event->parent ? p_event->parent->owner :
> > + p_event->owner;
> > +
> > if (tp_event->perf_perm) {
> > int ret = tp_event->perf_perm(tp_event, p_event);
> > if (ret)
> > @@ -32,7 +35,7 @@ static int perf_trace_event_perm(struct ftrace_event_call
> > *tp_event,
> >
> > /* The ftrace function trace is allowed only for root. */
> > if (ftrace_event_is_function(tp_event)) {
> > - if (perf_paranoid_tracepoint_raw() && !capable(CAP_SYS_ADMIN))
> > + if (perf_paranoid_tracepoint_raw() && !has_capability(owner,
> > CAP_SYS_ADMIN))
> > return -EPERM;
> >
> > /*
> > @@ -65,7 +68,7 @@ static int perf_trace_event_perm(struct ftrace_event_call
> > *tp_event,
> > * ...otherwise raw tracepoint data can be a severe data leak,
> > * only allow root to have these.
> > */
> > - if (perf_paranoid_tracepoint_raw() && !capable(CAP_SYS_ADMIN))
> > + if (perf_paranoid_tracepoint_raw() && !has_capability(owner,
> > CAP_SYS_ADMIN))
> > return -EPERM;
> >
> > return 0;
>
> You need to either hold rcu_read_lock() or otherwise ensure the owner is
> still valid.
ok, I'll resend
thanks,
jirka
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