From: Yu-cheng Yu <yu-cheng.yu@intel.com>
To: Dave Hansen <dave.hansen@intel.com>, Andy Lutomirski <luto@kernel.org>
Cc: X86 ML <x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
linux-arch <linux-arch@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>,
Balbir Singh <bsingharora@gmail.com>,
Borislav Petkov <bp@alien8.de>,
Cyrill Gorcunov <gorcunov@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Eugene Syromiatnikov <esyr@redhat.com>,
Florian Weimer <fweimer@redhat.com>,
"H.J. Lu" <hjl.tools@gmail.com>, Jann Horn <jannh@google.com>,
Jonathan Corbet <corbet@lwn.net>,
Kees Cook <keescook@chromium.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
Nadav Amit <nadav.amit@gmail.com>,
Oleg Nesterov <oleg@redhat.com>, Pavel Machek <pavel@ucw.cz>,
Peter Zijlstra <peterz@infradead.org>,
Randy Dunlap <rdunlap@infradead.org>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Vedvyas Shanbhogue <vedvyas.shanbhogue@intel.com>,
Dave Martin <Dave.Martin@arm.com>
Subject: Re: [PATCH v8 15/27] mm: Handle shadow stack page fault
Date: Wed, 14 Aug 2019 10:00:27 -0700 [thread overview]
Message-ID: <a47dd0338ff37ebaa7888f291d05a5fccf1cb44b.camel@intel.com> (raw)
In-Reply-To: <bf8a6390-97a6-1ab6-90ef-6399437ed38c@intel.com>
On Wed, 2019-08-14 at 09:48 -0700, Dave Hansen wrote:
> On 8/14/19 9:27 AM, Yu-cheng Yu wrote:
> > On Tue, 2019-08-13 at 15:55 -0700, Andy Lutomirski wrote:
> > > On Tue, Aug 13, 2019 at 2:02 PM Yu-cheng Yu <yu-cheng.yu@intel.com> wrote:
> > > > When a task does fork(), its shadow stack (SHSTK) must be duplicated
> > > > for the child. This patch implements a flow similar to copy-on-write
> > > > of an anonymous page, but for SHSTK.
> > > >
> > > > A SHSTK PTE must be RO and dirty. This dirty bit requirement is used
> > > > to effect the copying. In copy_one_pte(), clear the dirty bit from a
> > > > SHSTK PTE to cause a page fault upon the next SHSTK access. At that
> > > > time, fix the PTE and copy/re-use the page.
> > >
> > > Is using VM_SHSTK and special-casing all of this really better than
> > > using a special mapping or other pseudo-file-backed VMA and putting
> > > all the magic in the vm_operations?
> >
> > A special mapping is cleaner. However, we also need to exclude normal [RO +
> > dirty] pages from shadow stack.
>
> I don't understand what you are saying.
>
> Are you saying that we need this VM_SHSTK flag in order to exclude
> RO+HW-Dirty pages from being created in non-shadow-stack VMAs?
We use VM_SHSTK for page fault handling (the special-casing). If we have a
special mapping, all these become cleaner (but more code). However, we still
need most of the PTE macros (e.g. ptep_set_wrprotect, PAGE_DIRTY_SW, etc.).
Yu-cheng
next prev parent reply other threads:[~2019-08-14 17:10 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-13 20:51 [PATCH v8 00/27] Control-flow Enforcement: Shadow Stack Yu-cheng Yu
2019-08-13 20:51 ` [PATCH v8 01/27] Documentation/x86: Add CET description Yu-cheng Yu
2019-08-14 8:07 ` Florian Weimer
2019-08-14 15:57 ` Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 02/27] x86/cpufeatures: Add CET CPU feature flags for Control-flow Enforcement Technology (CET) Yu-cheng Yu
2019-08-21 10:20 ` Borislav Petkov
2019-08-21 14:46 ` Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 03/27] x86/fpu/xstate: Change names to separate XSAVES system and user states Yu-cheng Yu
2019-08-21 14:45 ` Borislav Petkov
2019-08-13 20:52 ` [PATCH v8 04/27] x86/fpu/xstate: Introduce XSAVES system states Yu-cheng Yu
2019-08-16 19:56 ` Thomas Gleixner
2019-08-16 19:59 ` Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 05/27] x86/fpu/xstate: Introduce CET MSR " Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 06/27] x86/cet: Add control protection exception handler Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 07/27] x86/cet/shstk: Add Kconfig option for user-mode shadow stack Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 08/27] mm: Introduce VM_SHSTK for shadow stack memory Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 09/27] mm/mmap: Prevent Shadow Stack VMA merges Yu-cheng Yu
2019-08-13 22:34 ` Dave Hansen
2019-08-14 16:20 ` Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 10/27] x86/mm: Change _PAGE_DIRTY to _PAGE_DIRTY_HW Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 11/27] x86/mm: Introduce _PAGE_DIRTY_SW Yu-cheng Yu
2019-08-13 23:02 ` Dave Hansen
2019-08-13 23:49 ` Andy Lutomirski
2019-08-14 16:42 ` Yu-cheng Yu
2019-08-14 16:58 ` Dave Hansen
2019-08-23 14:02 ` Peter Zijlstra
2019-08-27 22:37 ` Yu-cheng Yu
2019-08-28 7:03 ` Peter Zijlstra
2019-08-28 14:57 ` Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 12/27] drm/i915/gvt: Update _PAGE_DIRTY to _PAGE_DIRTY_BITS Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 13/27] x86/mm: Modify ptep_set_wrprotect and pmdp_set_wrprotect for _PAGE_DIRTY_SW Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 14/27] x86/mm: Shadow stack page fault error checking Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 15/27] mm: Handle shadow stack page fault Yu-cheng Yu
2019-08-13 22:55 ` Andy Lutomirski
2019-08-14 16:27 ` Yu-cheng Yu
2019-08-14 16:48 ` Dave Hansen
2019-08-14 17:00 ` Yu-cheng Yu [this message]
2019-08-13 20:52 ` [PATCH v8 16/27] mm: Handle THP/HugeTLB " Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 17/27] mm: Update can_follow_write_pte/pmd for shadow stack Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 18/27] mm: Introduce do_mmap_locked() Yu-cheng Yu
2019-08-20 1:02 ` Sean Christopherson
2019-08-20 16:08 ` Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 19/27] x86/cet/shstk: User-mode shadow stack support Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 20/27] x86/cet/shstk: Introduce WRUSS instruction Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 21/27] x86/cet/shstk: Handle signals for shadow stack Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 22/27] binfmt_elf: Extract .note.gnu.property from an ELF file Yu-cheng Yu
2019-08-16 13:55 ` Dave Martin
2019-08-20 10:02 ` Dave Martin
2019-08-13 20:52 ` [PATCH v8 23/27] x86/cet/shstk: ELF header parsing of Shadow Stack Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 24/27] x86/cet/shstk: Handle thread shadow stack Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 25/27] mm/mmap: Add Shadow stack pages to memory accounting Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 26/27] x86/cet/shstk: Add arch_prctl functions for Shadow Stack Yu-cheng Yu
2019-08-13 20:52 ` [PATCH v8 27/27] x86/cet/shstk: Add Shadow Stack instructions to opcode map Yu-cheng Yu
2019-11-08 13:27 ` Adrian Hunter
2019-11-08 18:09 ` Yu-cheng Yu
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