From: Mark Rutland <mark.rutland@arm.com> To: kernel-hardening@lists.openwall.com Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-x86_64@vger.kernel.org, juerg.haefliger@hpe.com, vpk@cs.columbia.edu Subject: Re: [kernel-hardening] [RFC PATCH v2 0/3] Add support for eXclusive Page Frame Ownership (XPFO) Date: Wed, 14 Sep 2016 10:49:02 +0100 [thread overview] Message-ID: <20160914094902.GA14330@leverpostej> (raw) In-Reply-To: <20160914093634.GB13121@leverpostej> On Wed, Sep 14, 2016 at 10:36:34AM +0100, Mark Rutland wrote: > On Wed, Sep 14, 2016 at 09:18:58AM +0200, Juerg Haefliger wrote: > > This patch series adds support for XPFO which protects against 'ret2dir' > > kernel attacks. The basic idea is to enforce exclusive ownership of page > > frames by either the kernel or userspace, unless explicitly requested by > > the kernel. Whenever a page destined for userspace is allocated, it is > > unmapped from physmap (the kernel's page table). When such a page is > > reclaimed from userspace, it is mapped back to physmap. > > Reference paper by the original patch authors: > > http://www.cs.columbia.edu/~vpk/papers/ret2dir.sec14.pdf > For both arm64 and x86_64, DEBUG_RODATA is mandatory (or soon to be so). > Assuming that implies a lack of execute permission for x86_64, that > should provide a similar level of protection against erroneously > branching to addresses in the linear map, without the complexity and > overhead of mapping/unmapping pages. > > So to me it looks like this approach may only be useful for > architectures without page-granular execute permission controls. > > Is this also intended to protect against erroneous *data* accesses to > the linear map? Now that I read the paper more carefully, I can see that this is the case, and this does catch issues which DEBUG_RODATA cannot. Apologies for the noise. Thanks, Mark.
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From: Mark Rutland <mark.rutland@arm.com> To: kernel-hardening@lists.openwall.com Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-x86_64@vger.kernel.org, juerg.haefliger@hpe.com, vpk@cs.columbia.edu Subject: Re: [kernel-hardening] [RFC PATCH v2 0/3] Add support for eXclusive Page Frame Ownership (XPFO) Date: Wed, 14 Sep 2016 10:49:02 +0100 [thread overview] Message-ID: <20160914094902.GA14330@leverpostej> (raw) In-Reply-To: <20160914093634.GB13121@leverpostej> On Wed, Sep 14, 2016 at 10:36:34AM +0100, Mark Rutland wrote: > On Wed, Sep 14, 2016 at 09:18:58AM +0200, Juerg Haefliger wrote: > > This patch series adds support for XPFO which protects against 'ret2dir' > > kernel attacks. The basic idea is to enforce exclusive ownership of page > > frames by either the kernel or userspace, unless explicitly requested by > > the kernel. Whenever a page destined for userspace is allocated, it is > > unmapped from physmap (the kernel's page table). When such a page is > > reclaimed from userspace, it is mapped back to physmap. > > Reference paper by the original patch authors: > > http://www.cs.columbia.edu/~vpk/papers/ret2dir.sec14.pdf > For both arm64 and x86_64, DEBUG_RODATA is mandatory (or soon to be so). > Assuming that implies a lack of execute permission for x86_64, that > should provide a similar level of protection against erroneously > branching to addresses in the linear map, without the complexity and > overhead of mapping/unmapping pages. > > So to me it looks like this approach may only be useful for > architectures without page-granular execute permission controls. > > Is this also intended to protect against erroneous *data* accesses to > the linear map? Now that I read the paper more carefully, I can see that this is the case, and this does catch issues which DEBUG_RODATA cannot. Apologies for the noise. Thanks, Mark. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2016-09-14 9:49 UTC|newest] Thread overview: 93+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-02-26 14:21 [RFC PATCH] Add support for eXclusive Page Frame Ownership (XPFO) Juerg Haefliger 2016-02-26 14:21 ` Juerg Haefliger 2016-03-01 1:31 ` Laura Abbott 2016-03-01 1:31 ` Laura Abbott 2016-03-21 8:37 ` Juerg Haefliger 2016-03-21 8:37 ` Juerg Haefliger 2016-03-28 19:29 ` Laura Abbott 2016-03-28 19:29 ` Laura Abbott 2016-03-01 2:10 ` Balbir Singh 2016-03-01 2:10 ` Balbir Singh 2016-03-21 8:44 ` Juerg Haefliger 2016-03-21 8:44 ` Juerg Haefliger 2016-04-01 0:21 ` Balbir Singh 2016-04-01 0:21 ` Balbir Singh 2016-09-02 11:39 ` [RFC PATCH v2 0/3] " Juerg Haefliger 2016-09-02 11:39 ` [kernel-hardening] " Juerg Haefliger 2016-09-02 11:39 ` Juerg Haefliger 2016-09-02 11:39 ` [RFC PATCH v2 1/3] " Juerg Haefliger 2016-09-02 11:39 ` [kernel-hardening] " Juerg Haefliger 2016-09-02 11:39 ` Juerg Haefliger 2016-09-02 11:39 ` [RFC PATCH v2 2/3] xpfo: Only put previous userspace pages into the hot cache Juerg Haefliger 2016-09-02 11:39 ` [kernel-hardening] " Juerg Haefliger 2016-09-02 11:39 ` Juerg Haefliger 2016-09-02 20:39 ` Dave Hansen 2016-09-02 20:39 ` [kernel-hardening] " Dave Hansen 2016-09-02 20:39 ` Dave Hansen 2016-09-05 11:54 ` Juerg Haefliger 2016-09-05 11:54 ` [kernel-hardening] " Juerg Haefliger 2016-09-02 11:39 ` [RFC PATCH v2 3/3] block: Always use a bounce buffer when XPFO is enabled Juerg Haefliger 2016-09-02 11:39 ` [kernel-hardening] " Juerg Haefliger 2016-09-02 11:39 ` Juerg Haefliger 2016-09-14 7:18 ` [RFC PATCH v2 0/3] Add support for eXclusive Page Frame Ownership (XPFO) Juerg Haefliger 2016-09-14 7:18 ` [kernel-hardening] " Juerg Haefliger 2016-09-14 7:18 ` Juerg Haefliger 2016-09-14 7:18 ` [RFC PATCH v2 1/3] " Juerg Haefliger 2016-09-14 7:18 ` [kernel-hardening] " Juerg Haefliger 2016-09-14 7:18 ` Juerg Haefliger 2016-09-14 7:19 ` [RFC PATCH v2 2/3] xpfo: Only put previous userspace pages into the hot cache Juerg Haefliger 2016-09-14 7:19 ` [kernel-hardening] " Juerg Haefliger 2016-09-14 7:19 ` Juerg Haefliger 2016-09-14 14:33 ` [kernel-hardening] " Dave Hansen 2016-09-14 14:33 ` Dave Hansen 2016-09-14 14:40 ` Juerg Haefliger 2016-09-14 14:48 ` Dave Hansen 2016-09-14 14:48 ` Dave Hansen 2016-09-21 5:32 ` Juerg Haefliger 2016-09-14 7:19 ` [RFC PATCH v2 3/3] block: Always use a bounce buffer when XPFO is enabled Juerg Haefliger 2016-09-14 7:19 ` [kernel-hardening] " Juerg Haefliger 2016-09-14 7:19 ` Juerg Haefliger 2016-09-14 7:33 ` Christoph Hellwig 2016-09-14 7:33 ` [kernel-hardening] " Christoph Hellwig 2016-09-14 7:33 ` Christoph Hellwig 2016-09-14 7:23 ` [RFC PATCH v2 0/3] Add support for eXclusive Page Frame Ownership (XPFO) Juerg Haefliger 2016-09-14 7:23 ` [kernel-hardening] " Juerg Haefliger 2016-09-14 9:36 ` [kernel-hardening] " Mark Rutland 2016-09-14 9:36 ` Mark Rutland 2016-09-14 9:49 ` Mark Rutland [this message] 2016-09-14 9:49 ` Mark Rutland 2016-11-04 14:45 ` [RFC PATCH v3 0/2] " Juerg Haefliger 2016-11-04 14:45 ` [kernel-hardening] " Juerg Haefliger 2016-11-04 14:45 ` Juerg Haefliger 2016-11-04 14:45 ` [RFC PATCH v3 1/2] " Juerg Haefliger 2016-11-04 14:45 ` [kernel-hardening] " Juerg Haefliger 2016-11-04 14:45 ` Juerg Haefliger 2016-11-04 14:50 ` Christoph Hellwig 2016-11-04 14:50 ` [kernel-hardening] " Christoph Hellwig 2016-11-04 14:50 ` Christoph Hellwig 2016-11-10 5:53 ` [kernel-hardening] " ZhaoJunmin Zhao(Junmin) 2016-11-10 5:53 ` ZhaoJunmin Zhao(Junmin) 2016-11-10 5:53 ` ZhaoJunmin Zhao(Junmin) 2016-11-10 19:11 ` Kees Cook 2016-11-10 19:11 ` [kernel-hardening] " Kees Cook 2016-11-10 19:11 ` Kees Cook 2016-11-15 11:15 ` Juerg Haefliger 2016-11-15 11:15 ` [kernel-hardening] " Juerg Haefliger 2016-11-15 11:15 ` Juerg Haefliger 2016-11-10 19:24 ` Kees Cook 2016-11-10 19:24 ` [kernel-hardening] " Kees Cook 2016-11-10 19:24 ` Kees Cook 2016-11-15 11:18 ` Juerg Haefliger 2016-11-15 11:18 ` [kernel-hardening] " Juerg Haefliger 2016-11-15 11:18 ` Juerg Haefliger 2016-11-24 10:56 ` AKASHI Takahiro 2016-11-24 10:56 ` [kernel-hardening] " AKASHI Takahiro 2016-11-24 10:56 ` AKASHI Takahiro 2016-11-28 11:15 ` Juerg Haefliger 2016-11-28 11:15 ` [kernel-hardening] " Juerg Haefliger 2016-12-09 9:02 ` AKASHI Takahiro 2016-12-09 9:02 ` [kernel-hardening] " AKASHI Takahiro 2016-12-09 9:02 ` AKASHI Takahiro 2016-11-04 14:45 ` [RFC PATCH v3 2/2] xpfo: Only put previous userspace pages into the hot cache Juerg Haefliger 2016-11-04 14:45 ` [kernel-hardening] " Juerg Haefliger 2016-11-04 14:45 ` Juerg Haefliger
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