From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751849AbaGGTqy (ORCPT ); Mon, 7 Jul 2014 15:46:54 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:59765 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750809AbaGGTqw (ORCPT ); Mon, 7 Jul 2014 15:46:52 -0400 Date: Mon, 7 Jul 2014 21:46:35 +0200 From: Peter Zijlstra To: Jiri Olsa Cc: Alexander Yarygin , Arnaldo Carvalho de Melo , Paul Mackerras , Ingo Molnar , Christian Borntraeger , linux-kernel@vger.kernel.org Subject: Re: [BUG] perf stat: events inheritance can break task targets Message-ID: <20140707194635.GZ6758@twins.programming.kicks-ass.net> References: <874myt86ju.wl%yarygin@linux.vnet.ibm.com> <20140707170040.GB2070@krava.redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="YMoJtYXQBeUqimUz" Content-Disposition: inline In-Reply-To: <20140707170040.GB2070@krava.redhat.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --YMoJtYXQBeUqimUz Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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_p= erf.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 =3D p_event->parent ? p_event->parent->owner : > + p_event->owner; > + > if (tp_event->perf_perm) { > int ret =3D tp_event->perf_perm(tp_event, p_event); > if (ret) > @@ -32,7 +35,7 @@ static int perf_trace_event_perm(struct ftrace_event_ca= ll *tp_event, > =20 > /* 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_A= DMIN)) > return -EPERM; > =20 > /* > @@ -65,7 +68,7 @@ static int perf_trace_event_perm(struct ftrace_event_ca= ll *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_AD= MIN)) > return -EPERM; > =20 > return 0; You need to either hold rcu_read_lock() or otherwise ensure the owner is still valid. --YMoJtYXQBeUqimUz Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJTuvkbAAoJEHZH4aRLwOS6/goP/Rhe/do1PfXbRHbDjQfIJO9X vCcH/2nIHm4u/xrISUCIjyJ/M6EW69t+eSaTwnccxERI/X5fsPtZDt4ofQP1wc/I s/PK2GsulZ2wiE1LInlnXFJrDOTipXQ0tbCDmbBzmSXDqd33eSwKtx4y9JaF9BlG 72eHoqVnvyiXU8L8SmjfDE8bvpqYLjSx9UH3EgRRkQ6vq/2BAtEjINH+IzN4Vbe7 Uxn8DynLxREwCUELTdOz0GxWSUP4Q8k7EwbPigmlldrPmjewBWFHFt6DZ9pYlKfQ ytI2HSn8HuJq23LFwXFWNFzuztAZscMX2tYETs5vtg2hxw5OznEUFNRkrzIxtSGb FLvU+03KCBByH02ILBKmkIWPpYxTmfPVin7I+xY6mlt4g6UhmpgQYnQDitcOcc/i 7oeprv2V+DcgNSA2Nn8yraLBUHj5XXRyIKIni5UVFXJyMWxEitKrESXXENqDh1ZM Yx+8D4+AepcqCCS86JbNgafVM3JZ3qB94tWs/3CgU7h7C1hbHMXuaj/RfpJQxLNu pp0WLJNXpMSewGav2xMznh+HwxtKHnDvhmU2GNEmhF/WgDJzyu8xuoZUEtkmwppS ULp19uHxpp2jUq6TQrMNf0clIHjka5UvmcU9uLxmxAem4i6PfBashiJCWckfIGTh oVzmJtXkenBJK66UU0VM =Ki9f -----END PGP SIGNATURE----- --YMoJtYXQBeUqimUz--