Commit f4be073d authored Jul 16, 2014 by Jiri Olsa Committed by Ingo Molnar Jul 28, 2014

perf: Check permission only for parent tracepoint event



There's no need to check cloned event's permission once the
parent was already checked.

Also the code is checking 'current' process permissions, which
is not owner process for cloned events, thus could end up with
wrong permission check result.

Reported-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Tested-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1405079782-8139-1-git-send-email-jolsa@kernel.org


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 5030c697

kernel/trace/trace_event_perf.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -30,6 +30,18 @@ static int perf_trace_event_perm(struct ftrace_event_call *tp_event,
		return ret;
		}

		/*
		* We checked and allowed to create parent,
		* allow children without checking.
		*/
		if (p_event->parent)
		return 0;

		/*
		* It's ok to check current process (owner) permissions in here,
		* because code below is called only via perf_event_open syscall.
		*/

		/* 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))