From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 72EF0C43381 for ; Tue, 26 Mar 2019 12:30:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3CD3620823 for ; Tue, 26 Mar 2019 12:30:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553603404; bh=sQM5jiXixK+TRDZp1EAAOo+9HgawHweRTNi+g/sfHoc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=z22+dn6JN4ESa6xGYYRDqK/G5Rd5PZJ+cE83J1xUCdLcQUFKAHAoAnYaqgrILTe/x HktXlCjdYuwjW/0AYSGDbsjvzbUao8YKElF2uet7pYyMGZuytyHGDQsMFx2HhsbW5k Ep7BduHHnTa0pBnzdN8n1syrUJSK/iynamsnctdQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726241AbfCZMaD (ORCPT ); Tue, 26 Mar 2019 08:30:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:51540 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726140AbfCZMaD (ORCPT ); Tue, 26 Mar 2019 08:30:03 -0400 Received: from devnote2 (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 541F32075E; Tue, 26 Mar 2019 12:30:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553603402; bh=sQM5jiXixK+TRDZp1EAAOo+9HgawHweRTNi+g/sfHoc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=xhZC2++NWBiXNXmdSXrpYb1M0HosHFRHAsRrGl+eSqgsAOxJpxtO7GrXy7xTnJ8bv UJWKjcHU5xyzizH4d/CifKUT7Jmvm7rzMXa1DYFNfqHBdo7e6IL/TvGyaoIpqIkxVO btrP1dkjJOnp828VwDufoLIZ0enWzb8MeOdPLvFs= Date: Tue, 26 Mar 2019 21:29:57 +0900 From: Masami Hiramatsu To: Matthew Garrett Cc: jmorris@namei.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, dhowells@redhat.com, Alexei Starovoitov , "Naveen N . Rao" , Anil S Keshavamurthy , davem@davemloft.net, Masami Hiramatsu Subject: Re: [PATCH 22/27] Lock down kprobes Message-Id: <20190326212957.f5b518990c14cf21262bfdcc@kernel.org> In-Reply-To: <20190325220954.29054-23-matthewgarrett@google.com> References: <20190325220954.29054-1-matthewgarrett@google.com> <20190325220954.29054-23-matthewgarrett@google.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On Mon, 25 Mar 2019 15:09:49 -0700 Matthew Garrett wrote: > From: David Howells > > Disallow the creation of kprobes when the kernel is locked down by > preventing their registration. This prevents kprobes from being used to > access kernel memory, either to make modifications or to steal crypto data. Hmm, if you enforce signature check of modules, those modules should be allowed to use kprobes? I think we should introduce some kind of trust inheritance from signed (trusted) modules. Thank you, > > Reported-by: Alexei Starovoitov > Signed-off-by: David Howells > Signed-off-by: Matthew Garrett > Cc: Naveen N. Rao > Cc: Anil S Keshavamurthy > Cc: davem@davemloft.net > Cc: Masami Hiramatsu > --- > kernel/kprobes.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > index f4ddfdd2d07e..6f66cca8e2c6 100644 > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -1552,6 +1552,9 @@ int register_kprobe(struct kprobe *p) > struct module *probed_mod; > kprobe_opcode_t *addr; > > + if (kernel_is_locked_down("Use of kprobes")) > + return -EPERM; > + > /* Adjust probe address from symbol */ > addr = kprobe_addr(p); > if (IS_ERR(addr)) > -- > 2.21.0.392.gf8f6787159e-goog > -- Masami Hiramatsu