From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933406AbaGPMdt (ORCPT ); Wed, 16 Jul 2014 08:33:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:9217 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932978AbaGPMdp (ORCPT ); Wed, 16 Jul 2014 08:33:45 -0400 From: Jiri Olsa To: linux-kernel@vger.kernel.org Cc: Jiri Olsa , Alexander Yarygin , Arnaldo Carvalho de Melo , Corey Ashford , Frederic Weisbecker , Ingo Molnar , Paul Mackerras , Peter Zijlstra Subject: [PATCH] perf: Check permission only for parent tracepoint event Date: Wed, 16 Jul 2014 14:33:29 +0200 Message-Id: <1405514009-15875-1-git-send-email-jolsa@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Cc: Alexander Yarygin Cc: Arnaldo Carvalho de Melo Cc: Corey Ashford Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1405079782-8139-1-git-send-email-jolsa@kernel.org Signed-off-by: Jiri Olsa --- kernel/trace/trace_event_perf.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c index 5d12bb407b44..4b9c114ee9de 100644 --- a/kernel/trace/trace_event_perf.c +++ b/kernel/trace/trace_event_perf.c @@ -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)) -- 1.8.3.1