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=-8.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable 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 E6A2FC10F11 for ; Wed, 10 Apr 2019 19:11:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BA8012064B for ; Wed, 10 Apr 2019 19:11:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="aW3vk4Pm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726886AbfDJTLZ (ORCPT ); Wed, 10 Apr 2019 15:11:25 -0400 Received: from mail-pl1-f196.google.com ([209.85.214.196]:36831 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726215AbfDJTLY (ORCPT ); Wed, 10 Apr 2019 15:11:24 -0400 Received: by mail-pl1-f196.google.com with SMTP id ck15so1994013plb.3 for ; Wed, 10 Apr 2019 12:11:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=epf1jTga2sUYPnvV+HKAcd7CD5M0nQur5VWq7xl7/+A=; b=aW3vk4PmkKJ3+s5QstWFSvn3XokjFFLL9KywsAVWS3QHMaeAWG9LM0hVyJdGMxAzzY cq/ehsoE0ok+i0B+wQB7ySLnIyL58jzCWloyMQly1OB/12REciWxiykXK9eHehhFvVN7 ljFwj8p5vMrVHLwNrtPONeNQLCWtho3BKlJsU= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=epf1jTga2sUYPnvV+HKAcd7CD5M0nQur5VWq7xl7/+A=; b=NwyM8qi7fMrBpPZk7AvJgwkInGGsF2M21Syfx91tmPJlIIvnHiRXBp5lcu850E8ASv 9mp40LpeAt4wHt/R1rhe+uHzc20szI7RJovvCIWmGELiz4fLCN+7ieYDNSGPKd1qczmw 9FTLtQ+D4VuZzgY/flBoDdaqxpkiBI/5TLlHrntNEkhKn5htaeHkWaosJsJbkL/lVQJp 4TDPKOlGBmEXKBd3z/OVjqSEdcfaUJE2eCZw96WrhdYKWqE6Liwv55l+G0Euj9QCHCzO 5d/ZKru11DpdO1fxvgftuhfAyU0d2X8f8T2WshA1d3qB9K6c+XKjRZi7l5CqtFsesnnb Effw== X-Gm-Message-State: APjAAAWXSVAxnBGHLCG1DDj9J0AgQQT/d3TqNZ3URodaSSlrOWojSv3H 9I0egwTjyNXAmccU2t4olz823IB28rY= X-Google-Smtp-Source: APXvYqwBYuhcm0WJMU3wQytbxKV/sxfR0zBawzwpendd3plns+Pqom3qYpHbuwUcy24bMOStT/QoeA== X-Received: by 2002:a17:902:2a89:: with SMTP id j9mr45880910plb.272.1554923482834; Wed, 10 Apr 2019 12:11:22 -0700 (PDT) Received: from localhost ([2620:15c:6:12:9c46:e0da:efbf:69cc]) by smtp.gmail.com with ESMTPSA id a24sm39739987pgv.10.2019.04.10.12.11.21 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 10 Apr 2019 12:11:21 -0700 (PDT) Date: Wed, 10 Apr 2019 15:11:20 -0400 From: Joel Fernandes To: linux-kernel@vger.kernel.org Cc: paulmck@linux.vnet.ibm.com, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, rcu@vger.kernel.org, kernel-hardening@lists.openwall.com, kernel-team@android.com, keescook@chromium.org, Jessica Yu Subject: Re: [PATCH v2 1/3] module: Prepare for addition of new ro_after_init sections Message-ID: <20190410191120.GA109588@google.com> References: <20190410190823.109172-1-joel@joelfernandes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190410190823.109172-1-joel@joelfernandes.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 10, 2019 at 03:08:21PM -0400, Joel Fernandes (Google) wrote: > For the purposes of hardening modules by adding sections to > ro_after_init sections, prepare for addition of new ro_after_init > entries which we do in future patches. Create a table to which new > entries could be added later. This makes it less error prone and reduce > code duplication. > > Cc: paulmck@linux.vnet.ibm.com > Cc: rostedt@goodmis.org > Cc: mathieu.desnoyers@efficios.com > Cc: rcu@vger.kernel.org > Cc: kernel-hardening@lists.openwall.com > Cc: kernel-team@android.com > Suggested-by: keescook@chromium.org > Reviewed-by: keescook@chromium.org > Acked-by: rostedt@goodmis.org > Signed-off-by: Joel Fernandes (Google) > > --- > kernel/module.c | 41 +++++++++++++++++++++++------------------ > 1 file changed, 23 insertions(+), 18 deletions(-) > > diff --git a/kernel/module.c b/kernel/module.c > index 524da609c884..1acddb93282a 100644 > --- a/kernel/module.c > +++ b/kernel/module.c > @@ -3300,11 +3300,27 @@ static bool blacklisted(const char *module_name) > } > core_param(module_blacklist, module_blacklist, charp, 0400); > > +/* > + * Mark ro_after_init section with SHF_RO_AFTER_INIT so that > + * layout_sections() can put it in the right place. > + * Note: ro_after_init sections also have SHF_{WRITE,ALLOC} set. > + */ > +static char *ro_after_init_sections[] = { > + ".data..ro_after_init", > + > + /* > + * __jump_table structures are never modified, with the exception of > + * entries that refer to code in the __init section, which are > + * annotated as such at module load time. > + */ > + "__jump_table", > +}; > + > static struct module *layout_and_allocate(struct load_info *info, int flags) > { > struct module *mod; > unsigned int ndx; > - int err; > + int err, i; > > err = check_modinfo(info->mod, info, flags); > if (err) > @@ -3319,23 +3335,12 @@ static struct module *layout_and_allocate(struct load_info *info, int flags) > /* We will do a special allocation for per-cpu sections later. */ > info->sechdrs[info->index.pcpu].sh_flags &= ~(unsigned long)SHF_ALLOC; > > - /* > - * Mark ro_after_init section with SHF_RO_AFTER_INIT so that > - * layout_sections() can put it in the right place. > - * Note: ro_after_init sections also have SHF_{WRITE,ALLOC} set. > - */ > - ndx = find_sec(info, ".data..ro_after_init"); > - if (ndx) > - info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT; > - /* > - * Mark the __jump_table section as ro_after_init as well: these data > - * structures are never modified, with the exception of entries that > - * refer to code in the __init section, which are annotated as such > - * at module load time. > - */ > - ndx = find_sec(info, "__jump_table"); > - if (ndx) > - info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT; > + /* Set sh_flags for read-only after init sections */ > + for (i = 0; ro_after_init_sections[i]; i++) { Seems the fixup for this based on Kees suggestion of using NULL got squashed into 2/3, so allow me to send a v3 to fix this ;-) Sorry! I am doing that now. The patches applied together are still code-correct thought. thanks, - Joel