From patchwork Wed Feb 15 07:27:35 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kaiwan N Billimoria X-Patchwork-Id: 9573457 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5771D60493 for ; Wed, 15 Feb 2017 07:28:27 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4403C28417 for ; Wed, 15 Feb 2017 07:28:27 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 35CCA28446; Wed, 15 Feb 2017 07:28:27 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id B8B3828417 for ; Wed, 15 Feb 2017 07:28:25 +0000 (UTC) Received: (qmail 15780 invoked by uid 550); 15 Feb 2017 07:28:23 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 15753 invoked from network); 15 Feb 2017 07:28:22 -0000 Date: Wed, 15 Feb 2017 12:57:35 +0530 From: Kaiwan N Billimoria To: Kees Cook Cc: Laura Abbott , "kernel-hardening@lists.openwall.com" Message-ID: <20170215125735.17920d58@kaiwan-T460> In-Reply-To: References: <20170118095155.5e3bf976@kaiwan-T460> <90224a2d-2bfc-8c1e-1f2c-ca5bfbdb4879@redhat.com> <20170203101949.4c6908be@kaiwan-T460> <20170209090714.63ce6333@kaiwan-T460> Organization: kaiwanTECH X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-CMAE-Envelope: MS4wfL8R1GanA/sQ7EqiPuDCsCnNuOprLePeszAUz9UVj0QEZnb9gQ4oMd+49AWXTsZwdUds7McF/SWWasHfz2Mqu9DmQ6JFadpTkF8dXQAToPVXWJ0j2fqO MotGH/7RG6SNpjRSSaO9QhG9n2/SSpO3plhB+iblHt1WVVPZ76taVXiYVaavUOag8Fm52wfBhM6nDarDc+9EvIUkWNWQ5XqnPdUhP+TUa5GVTiB9Lv1hSZU4 KiZcIh9xRvBqJ1BeoDOqOg== Subject: Re: [kernel-hardening] Merge in PAX_MEMORY_SANITIZE work from grsec to linux-next X-Virus-Scanned: ClamAV using ClamSMTP Okay, I've incorporated your suggestions. Of course, the printk's are temporary. Pl see: - the updated patch, and - a 'truth table' enumerating some basic testing with these configs, below: --- --- (Minimal) Testing done so far: -------------------------------+----------------------+----------------------- | Kconfig | kernel cmdline | Result* | |--------------+---------------+----------------------+----------------------| SLUB_DEBUG[_ON]|MEMORY_SANITIZE|page_poison|slub_debug|page_poison|slub_debug| |--------------+---------------+----------------------+----------------------| Y | Y | np[1] | np | on | p | Y | Y | np[1] | =p | on | p | Y | Y | np[1] | =fzu | on | p | Y | Y | np[1] | =fzup | on | p | Y | Y | np[1] | = | on | p | |--------------+---------------+----------------------+----------------------| Y | Y | =off | np | on | p | Y | Y | =off | =p | on | p | Y | Y | =off | =fzu | on | p | Y | Y | =off | = | on | p | |--------------+---------------+----------------------+----------------------| Y | Y | =on | np | on | p | Y | Y | =on | =p | on | p | Y | Y | =on | =fzu | on | p | Y | Y | =on | = | on | p | |--------------+---------------+----------------------+----------------------| [1] np = not passed * Result: MEMORY_SANITIZE='y' => page_poison should be 'on' and slub_debug='p' (implying SLAB_POISON bit set). So far, all tests passed.. Thanks, Kaiwan. On Tue, 14 Feb 2017 09:19:27 -0800 Kees Cook wrote: > On Mon, Feb 13, 2017 at 7:01 PM, Kaiwan N Billimoria > wrote: > > Thanks for your response... > >> > >> > >> > >> > +config MEMORY_SANITIZE > >> > + bool "Enable memory sanitization features" > >> > + select SLUB_DEBUG > >> > + select PAGE_POISONING > >> > + select PAGE_POISONING_NO_SANITY if HIBERNATION > >> > + ---help--- > >> > + This option enables ... > >> > >> Good start! Why the "if HIBERNATION" bit? It seems like sanity > >> checks are very expensive, so we'd not want it as part of this > >> config? > > Okay, I wasn't sure. So would it be (more) correct to retain the > > first two configs plus > > PAGE_POISONING_NO_SANITY (without the if)? > > I think so, yes. We may need to tweak it in the future, but I think > that's the correct config for now. > > >> > #if defined(CONFIG_SLUB_DEBUG_ON) > >> > +#if defined(CONFIG_MEMORY_SANITIZE) > >> > +/* With 'memory sanitize' On, slub_debug should be 'P' */ > >> > +static int slub_debug = SLAB_POISON; > >> > +#else > >> > static int slub_debug = DEBUG_DEFAULT_FLAGS; > >> > +#endif /* CONFIG_MEMORY_SANITIZE */ > >> > #else > >> > static int slub_debug; > >> > -#endif > >> > +#endif /* CONFIG_SLUB_DEBUG_ON */ > >> > >> Could the definition of DEBUG_DEFAULT_FLAGS be adjusted instead of > >> doing the ifdefs here in the .c file? Or, perhaps do a slub_debug > >> |= SLAB_POISON in memory_sanitize_init()? > >> > > Yes, the latter sounds good but the init function is in > > mm/page_poison.c and the slub_debug var is a static in mm/slub.c . > > Any suggestions? > > Perhaps add another early_init like you did the page_poison.c? > > -Kees > diff --git a/init/main.c b/init/main.c index ef47035..ba44574 100644 --- a/init/main.c +++ b/init/main.c @@ -1028,6 +1028,11 @@ static noinline void __init kernel_init_freeable(void) do_basic_setup(); +#ifdef CONFIG_MEMORY_SANITIZE + pr_debug("[CONFIG_MEMORY_SANITIZE]: page_poisoning_enabled? %s\n", + page_poisoning_enabled() ? "yes" : "no"); +#endif + /* Open the /dev/console on the rootfs, this should never fail */ if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0) pr_err("Warning: unable to open an initial console.\n"); diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug index 3e5eada..fbb4290 100644 --- a/mm/Kconfig.debug +++ b/mm/Kconfig.debug @@ -97,3 +97,24 @@ config DEBUG_RODATA_TEST ---help--- This option enables a testcase for the setting rodata read-only. +config MEMORY_SANITIZE + bool "Enable memory sanitization features" + select SLUB_DEBUG + select PAGE_POISONING + select PAGE_POISONING_NO_SANITY + ---help--- + This option enables memory sanitization features. Particularly, + when you turn on this option, it auto-enables: + - SLUB debug + - page poisoning + - page poisoning no sanity. + + Implication: turning this option on _will_ implicitly enable: + - the SLUB_DEBUG switch to the equivalent of the kernel command-line + 'slub_debug=p' ; (where p=PAGE_POISON), + - page poisoning, equivalent to passing the kernel command-line option + 'page_poison=on', + irrespective of whether the options are explicitly passed or not. + + If unsure, say N. + diff --git a/mm/page_poison.c b/mm/page_poison.c index 2e647c6..8d1e883 100644 --- a/mm/page_poison.c +++ b/mm/page_poison.c @@ -49,6 +49,17 @@ struct page_ext_operations page_poisoning_ops = { .init = init_page_poisoning, }; +static int __init memory_sanitize_pagepoison_init(void) +{ + /* With 'memory sanitize' On, page poisoning Must be turned on */ + if (IS_ENABLED(CONFIG_MEMORY_SANITIZE)) { + want_page_poisoning = true; + __page_poisoning_enabled = true; + } + return 0; +} +early_initcall(memory_sanitize_pagepoison_init); + static inline void set_page_poison(struct page *page) { struct page_ext *page_ext; diff --git a/mm/slub.c b/mm/slub.c index d24e1ce..62de543 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -457,6 +457,17 @@ static int slub_debug; static char *slub_debug_slabs; static int disable_higher_order_debug; +static int __init memory_sanitize_slubdebug_init(void) +{ +/* With 'memory sanitize' On, slub_debug Must be set to 'p' */ + if (IS_ENABLED(CONFIG_SLUB_DEBUG_ON) && + IS_ENABLED(CONFIG_MEMORY_SANITIZE)) { + slub_debug |= SLAB_POISON; + } + return 0; +} +early_initcall(memory_sanitize_slubdebug_init); + /* * slub is about to manipulate internal object metadata. This memory lies * outside the range of the allocated object, so accessing it would normally @@ -5675,6 +5686,11 @@ static int __init slab_sysfs_init(void) struct kmem_cache *s; int err; +#ifdef CONFIG_MEMORY_SANITIZE + pr_info("[CONFIG_MEMORY_SANITIZE]: slub_debug = P? %s [0x%x]\n", + slub_debug & SLAB_POISON ? "yes" : "no", slub_debug); +#endif + mutex_lock(&slab_mutex); slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);