From: Dave Hansen <dave.hansen@intel.com>
To: "Yu, Yu-cheng" <yu-cheng.yu@intel.com>,
Andy Lutomirski <luto@kernel.org>
Cc: Dave Martin <Dave.Martin@arm.com>,
"H.J. Lu" <hjl.tools@gmail.com>,
Florian Weimer <fweimer@redhat.com>, 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>,
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>,
Weijiang Yang <weijiang.yang@intel.com>
Subject: Re: [PATCH v11 25/25] x86/cet/shstk: Add arch_prctl functions for shadow stack
Date: Wed, 9 Sep 2020 16:29:53 -0700 [thread overview]
Message-ID: <b3379d26-d8a7-deb7-59f1-c994bb297dcb@intel.com> (raw)
In-Reply-To: <cbec8861-8722-ec31-2c02-1cfed20255eb@intel.com>
On 9/9/20 4:25 PM, Yu, Yu-cheng wrote:
> On 9/9/2020 4:11 PM, Dave Hansen wrote:
>> On 9/9/20 4:07 PM, Yu, Yu-cheng wrote:
>>> What if a writable mapping is passed to madvise(MADV_SHSTK)? Should
>>> that be rejected?
>>
>> It doesn't matter to me. Even if it's readable, it _stops_ being even
>> directly readable after it's a shadow stack, right? I don't think
>> writes are special in any way. If anything, we *want* it to be writable
>> because that indicates that it can be written to, and we will want to
>> write to it soon.
>>
> But in a PROT_WRITE mapping, all the pte's have _PAGE_BIT_RW set. To
> change them to shadow stack, we need to clear that bit from the pte's.
> That will be like mprotect_fixup()/change_protection_range().
The page table hardware bits don't matter. The user-visible protection
effects matter.
For instance, we have PROT_EXEC, which *CLEARS* a hardware NX PTE bit.
The PROT_ permissions are independent of the hardware.
I don't think the interface should be influenced at *all* by what whacko
PTE bit combinations we have to set to get the behavior.
next prev parent reply other threads:[~2020-09-10 2:24 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-25 0:25 [PATCH v11 00/25] Control-flow Enforcement: Shadow Stack Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 01/25] Documentation/x86: Add CET description Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 02/25] x86/cpufeatures: Add CET CPU feature flags for Control-flow Enforcement Technology (CET) Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 03/25] x86/fpu/xstate: Introduce CET MSR XSAVES supervisor states Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 04/25] x86/cet: Add control-protection fault handler Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 05/25] x86/cet/shstk: Add Kconfig option for user-mode Shadow Stack Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 06/25] x86/mm: Change _PAGE_DIRTY to _PAGE_DIRTY_HW Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 07/25] x86/mm: Remove _PAGE_DIRTY_HW from kernel RO pages Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 08/25] x86/mm: Introduce _PAGE_COW Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 09/25] drm/i915/gvt: Change _PAGE_DIRTY to _PAGE_DIRTY_BITS Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 10/25] x86/mm: Update pte_modify for _PAGE_COW Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 11/25] x86/mm: Update ptep_set_wrprotect() and pmdp_set_wrprotect() for transition from _PAGE_DIRTY_HW to _PAGE_COW Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 12/25] mm: Introduce VM_SHSTK for shadow stack memory Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 13/25] x86/mm: Shadow Stack page fault error checking Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 14/25] x86/mm: Update maybe_mkwrite() for shadow stack Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 15/25] mm: Fixup places that call pte_mkwrite() directly Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 16/25] mm: Add guard pages around a shadow stack Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 17/25] mm/mmap: Add shadow stack pages to memory accounting Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 18/25] mm: Update can_follow_write_pte() for shadow stack Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 19/25] mm: Re-introduce do_mmap_pgoff() Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 20/25] x86/cet/shstk: User-mode shadow stack support Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 21/25] x86/cet/shstk: Handle signals for shadow stack Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 22/25] binfmt_elf: Define GNU_PROPERTY_X86_FEATURE_1_AND properties Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 23/25] ELF: Introduce arch_setup_elf_property() Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 24/25] x86/cet/shstk: Handle thread shadow stack Yu-cheng Yu
2020-08-25 0:25 ` [PATCH v11 25/25] x86/cet/shstk: Add arch_prctl functions for " Yu-cheng Yu
2020-08-25 0:36 ` Andy Lutomirski
2020-08-25 18:43 ` Yu, Yu-cheng
2020-08-25 19:19 ` Dave Hansen
2020-08-25 21:04 ` Yu, Yu-cheng
2020-08-25 23:20 ` Dave Hansen
2020-08-25 23:34 ` Yu, Yu-cheng
2020-08-26 16:46 ` Dave Martin
2020-08-26 16:51 ` Florian Weimer
2020-08-26 17:04 ` Andy Lutomirski
2020-08-26 18:49 ` Yu, Yu-cheng
2020-08-26 19:43 ` H.J. Lu
2020-08-26 19:57 ` Dave Hansen
2020-08-27 13:26 ` H.J. Lu
2020-09-01 10:28 ` Dave Martin
2020-09-01 17:23 ` Yu, Yu-cheng
2020-09-01 17:45 ` Andy Lutomirski
2020-09-01 18:11 ` Dave Hansen
2020-09-02 13:58 ` Dave Martin
[not found] ` <46dffdfd-92f8-0f05-6164-945f217b0958@intel.com>
2020-09-08 17:57 ` Dave Hansen
2020-09-08 18:25 ` Yu, Yu-cheng
2020-09-09 22:08 ` Yu, Yu-cheng
2020-09-09 22:59 ` Dave Hansen
2020-09-09 23:07 ` Yu, Yu-cheng
2020-09-09 23:11 ` Dave Hansen
2020-09-09 23:25 ` Yu, Yu-cheng
2020-09-09 23:29 ` Dave Hansen [this message]
2020-09-09 23:45 ` Yu, Yu-cheng
2020-09-11 22:59 ` Yu-cheng Yu
2020-09-14 14:50 ` [NEEDS-REVIEW] " Dave Hansen
2020-09-14 18:31 ` Andy Lutomirski
2020-09-14 20:44 ` Yu, Yu-cheng
2020-09-14 21:14 ` Dave Hansen
2020-09-16 13:52 ` Andy Lutomirski
2020-09-16 19:25 ` Yu, Yu-cheng
2021-09-14 1:33 ` [NEEDS-REVIEW] " Edgecombe, Rick P
2021-09-14 9:53 ` Borislav Petkov
2021-09-20 16:48 ` Andy Lutomirski
2021-09-23 23:32 ` Edgecombe, Rick P
[not found] ` <bf2ab309-f8c4-83da-1c0a-5684e5bc5c82@intel.com>
2020-09-15 19:08 ` Yu-cheng Yu
2020-09-15 19:24 ` Dave Hansen
2020-09-15 20:16 ` Yu, Yu-cheng
2020-08-26 17:08 ` Dave Martin
2020-08-27 13:18 ` Florian Weimer
2020-08-27 13:28 ` H.J. Lu
2020-08-27 13:36 ` Florian Weimer
2020-08-27 14:07 ` H.J. Lu
2020-08-27 14:08 ` H.J. Lu
2020-09-01 17:49 ` Yu, Yu-cheng
2020-09-01 17:50 ` Florian Weimer
2020-09-01 17:58 ` Yu, Yu-cheng
2020-09-01 18:17 ` Florian Weimer
2020-09-01 18:19 ` H.J. Lu
2020-09-01 18:24 ` Yu, Yu-cheng
2020-08-27 18:13 ` Yu, Yu-cheng
2020-08-27 18:56 ` Andy Lutomirski
2020-08-27 19:33 ` Yu, Yu-cheng
2020-08-27 19:37 ` H.J. Lu
2020-08-28 1:35 ` Andy Lutomirski
2020-08-28 1:44 ` H.J. Lu
2020-08-28 6:23 ` Florian Weimer
2020-08-28 11:37 ` H.J. Lu
2020-08-28 17:39 ` Andy Lutomirski
2020-08-28 17:45 ` H.J. Lu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=b3379d26-d8a7-deb7-59f1-c994bb297dcb@intel.com \
--to=dave.hansen@intel.com \
--cc=Dave.Martin@arm.com \
--cc=arnd@arndb.de \
--cc=bp@alien8.de \
--cc=bsingharora@gmail.com \
--cc=corbet@lwn.net \
--cc=dave.hansen@linux.intel.com \
--cc=esyr@redhat.com \
--cc=fweimer@redhat.com \
--cc=gorcunov@gmail.com \
--cc=hjl.tools@gmail.com \
--cc=hpa@zytor.com \
--cc=jannh@google.com \
--cc=keescook@chromium.org \
--cc=linux-api@vger.kernel.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=mike.kravetz@oracle.com \
--cc=mingo@redhat.com \
--cc=nadav.amit@gmail.com \
--cc=oleg@redhat.com \
--cc=pavel@ucw.cz \
--cc=peterz@infradead.org \
--cc=ravi.v.shankar@intel.com \
--cc=rdunlap@infradead.org \
--cc=tglx@linutronix.de \
--cc=vedvyas.shanbhogue@intel.com \
--cc=weijiang.yang@intel.com \
--cc=x86@kernel.org \
--cc=yu-cheng.yu@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).