Messages in this thread | | | Date | Tue, 8 Jul 2014 08:59:01 +0200 | From | Jiri Olsa <> | Subject | Re: [BUG] perf stat: events inheritance can break task targets |
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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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