From: Kees Cook <keescook@chromium.org>
To: "Yu, Yu-cheng" <yu-cheng.yu@intel.com>
Cc: x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
linux-api@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
Andy Lutomirski <luto@kernel.org>,
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>,
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>,
Weijiang Yang <weijiang.yang@intel.com>,
Pengfei Xu <pengfei.xu@intel.com>
Subject: Re: [PATCH v19 24/25] x86/cet/shstk: Add arch_prctl functions for shadow stack
Date: Fri, 5 Feb 2021 10:26:52 -0800 [thread overview]
Message-ID: <202102051026.B250352D4@keescook> (raw)
In-Reply-To: <6d7dd90f-dc03-06ce-57a2-57e4c2f803f3@intel.com>
On Thu, Feb 04, 2021 at 03:41:59PM -0800, Yu, Yu-cheng wrote:
> On 2/4/2021 12:35 PM, Kees Cook wrote:
> > On Wed, Feb 03, 2021 at 02:55:46PM -0800, Yu-cheng Yu wrote:
> > > arch_prctl(ARCH_X86_CET_STATUS, u64 *args)
> > > Get CET feature status.
> > >
> > > The parameter 'args' is a pointer to a user buffer. The kernel returns
> > > the following information:
> > >
> > > *args = shadow stack/IBT status
> > > *(args + 1) = shadow stack base address
> > > *(args + 2) = shadow stack size
> >
> > What happens if this needs to grow in the future? Should the first u64
> > contain the array size?
> >
> > Otherwise, looks sensible.
> >
> > -Kees
> >
>
> The first item is a bitmap, and there are two possible bits. Should there
> be a need, we can then do things about it. My thought at the moment is, we
> may not meet the situation. Can we keep this for now?
Ah, good point. Yes, since that's a bitmap it ends up describing what
follows. This is fine as-is. Thanks!
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
next prev parent reply other threads:[~2021-02-05 18:30 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-03 22:55 [PATCH v19 00/25] Control-flow Enforcement: Shadow Stack Yu-cheng Yu
2021-02-03 22:55 ` [PATCH v19 01/25] Documentation/x86: Add CET description Yu-cheng Yu
2021-02-04 19:52 ` Kees Cook
2021-02-04 20:03 ` Yu, Yu-cheng
2021-02-03 22:55 ` [PATCH v19 02/25] x86/cet/shstk: Add Kconfig option for user-mode control-flow protection Yu-cheng Yu
2021-02-04 19:56 ` Kees Cook
2021-02-05 0:05 ` Yu, Yu-cheng
2021-02-03 22:55 ` [PATCH v19 03/25] x86/cpufeatures: Add CET CPU feature flags for Control-flow Enforcement Technology (CET) Yu-cheng Yu
2021-02-04 19:57 ` Kees Cook
2021-02-03 22:55 ` [PATCH v19 04/25] x86/cpufeatures: Introduce X86_FEATURE_CET and setup functions Yu-cheng Yu
2021-02-04 19:58 ` Kees Cook
2021-02-05 13:43 ` Borislav Petkov
2021-02-05 16:15 ` Yu, Yu-cheng
2021-02-03 22:55 ` [PATCH v19 05/25] x86/fpu/xstate: Introduce CET MSR and XSAVES supervisor states Yu-cheng Yu
2021-02-04 19:59 ` Kees Cook
2021-02-03 22:55 ` [PATCH v19 06/25] x86/cet: Add control-protection fault handler Yu-cheng Yu
2021-02-04 20:09 ` Kees Cook
2021-02-05 0:10 ` Yu, Yu-cheng
2021-02-05 13:59 ` Borislav Petkov
2021-02-05 18:00 ` Yu, Yu-cheng
2021-02-05 18:29 ` Kees Cook
2021-02-08 18:20 ` Borislav Petkov
2021-02-08 18:50 ` Yu, Yu-cheng
2021-02-08 18:53 ` Borislav Petkov
2021-02-08 19:23 ` Yu, Yu-cheng
2021-02-08 19:48 ` Borislav Petkov
2021-02-08 20:11 ` Yu, Yu-cheng
2021-02-03 22:55 ` [PATCH v19 07/25] x86/mm: Remove _PAGE_DIRTY from kernel RO pages Yu-cheng Yu
2021-02-04 20:10 ` Kees Cook
2021-02-03 22:55 ` [PATCH v19 08/25] x86/mm: Introduce _PAGE_COW Yu-cheng Yu
2021-02-04 20:19 ` Kees Cook
2021-02-04 20:27 ` Dave Hansen
2021-02-05 18:41 ` Yu, Yu-cheng
2021-02-08 23:03 ` Yu, Yu-cheng
2021-02-05 18:58 ` Yu, Yu-cheng
2021-02-03 22:55 ` [PATCH v19 09/25] drm/i915/gvt: Change _PAGE_DIRTY to _PAGE_DIRTY_BITS Yu-cheng Yu
2021-02-03 22:55 ` [PATCH v19 10/25] x86/mm: Update pte_modify for _PAGE_COW Yu-cheng Yu
2021-02-04 20:20 ` Kees Cook
2021-02-03 22:55 ` [PATCH v19 11/25] x86/mm: Update ptep_set_wrprotect() and pmdp_set_wrprotect() for transition from _PAGE_DIRTY to _PAGE_COW Yu-cheng Yu
2021-02-04 20:21 ` Kees Cook
2021-02-03 22:55 ` [PATCH v19 12/25] mm: Introduce VM_SHSTK for shadow stack memory Yu-cheng Yu
2021-02-04 20:46 ` Cyrill Gorcunov
2021-02-04 21:48 ` Yu, Yu-cheng
2021-02-03 22:55 ` [PATCH v19 13/25] x86/mm: Shadow Stack page fault error checking Yu-cheng Yu
2021-02-03 22:55 ` [PATCH v19 14/25] x86/mm: Update maybe_mkwrite() for shadow stack Yu-cheng Yu
2021-02-04 20:22 ` Kees Cook
2021-02-03 22:55 ` [PATCH v19 15/25] mm: Fixup places that call pte_mkwrite() directly Yu-cheng Yu
2021-02-04 20:22 ` Kees Cook
2021-02-03 22:55 ` [PATCH v19 16/25] mm: Add guard pages around a shadow stack Yu-cheng Yu
2021-02-04 20:24 ` Kees Cook
2021-02-03 22:55 ` [PATCH v19 17/25] mm/mmap: Add shadow stack pages to memory accounting Yu-cheng Yu
2021-02-04 20:24 ` Kees Cook
2021-02-03 22:55 ` [PATCH v19 18/25] mm: Update can_follow_write_pte() for shadow stack Yu-cheng Yu
2021-02-04 20:27 ` Kees Cook
2021-02-03 22:55 ` [PATCH v19 19/25] mm: Re-introduce vm_flags to do_mmap() Yu-cheng Yu
2021-02-04 20:28 ` Kees Cook
2021-02-03 22:55 ` [PATCH v19 20/25] x86/cet/shstk: User-mode shadow stack support Yu-cheng Yu
2021-02-04 20:29 ` Kees Cook
2021-02-03 22:55 ` [PATCH v19 21/25] x86/cet/shstk: Handle signals for shadow stack Yu-cheng Yu
2021-02-03 22:55 ` [PATCH v19 22/25] ELF: Introduce arch_setup_elf_property() Yu-cheng Yu
2021-02-04 20:33 ` Kees Cook
2021-02-03 22:55 ` [PATCH v19 23/25] x86/cet/shstk: Handle thread shadow stack Yu-cheng Yu
2021-02-03 22:55 ` [PATCH v19 24/25] x86/cet/shstk: Add arch_prctl functions for " Yu-cheng Yu
2021-02-04 20:35 ` Kees Cook
2021-02-04 23:41 ` Yu, Yu-cheng
2021-02-05 18:26 ` Kees Cook [this message]
2021-02-03 22:55 ` [PATCH v19 25/25] mm: Introduce PROT_SHSTK " Yu-cheng Yu
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