From: Florian Weimer <fweimer@redhat.com>
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>,
"the arch/x86 maintainers" <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>, 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>,
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>,
Dave Martin <Dave.Martin@arm.com>,
Weijiang Yang <weijiang.yang@intel.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
joao.moreira@intel.com, John Allen <john.allen@amd.com>,
Kostya Serebryany <kcc@google.com>,
Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH 34/35] x86/cet/shstk: Support wrss for userspace
Date: Mon, 31 Jan 2022 19:45:10 +0100 [thread overview]
Message-ID: <87a6fb7nih.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <CAMe9rOrVvjL1F3UgOWL-gAGRyyiG6r20TWUusEUFhZMEEAjH7w@mail.gmail.com> (H. J. Lu's message of "Mon, 31 Jan 2022 10:26:49 -0800")
* H. J. Lu:
> On Sun, Jan 30, 2022 at 11:57 PM Florian Weimer <fweimer@redhat.com> wrote:
>>
>> * Rick Edgecombe:
>>
>> > For the current shadow stack implementation, shadow stacks contents cannot
>> > be arbitrarily provisioned with data. This property helps apps protect
>> > themselves better, but also restricts any potential apps that may want to
>> > do exotic things at the expense of a little security.
>> >
>> > The x86 shadow stack feature introduces a new instruction, wrss, which
>> > can be enabled to write directly to shadow stack permissioned memory from
>> > userspace. Allow it to get enabled via the prctl interface.
>>
>> Why can't this be turned on unconditionally?
>
> WRSS can be a security risk since it defeats the whole purpose of
> Shadow Stack. If an application needs to write to shadow stack,
> it can make a syscall to enable it. After the CET patches are checked
> in Linux kernel, I will make a proposal to allow applications or shared
> libraries to opt-in WRSS through a linker option, a compiler option or
> a function attribute.
Ahh, that makes sense. I assumed that without WRSS, the default was to
allow plain writes. 8-)
Thanks,
Florian
next prev parent reply other threads:[~2022-01-31 18:45 UTC|newest]
Thread overview: 154+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-30 21:18 [PATCH 00/35] Shadow stacks for userspace Rick Edgecombe
2022-01-30 21:18 ` [PATCH 01/35] Documentation/x86: Add CET description Rick Edgecombe
2022-01-30 21:18 ` [PATCH 02/35] x86/cet/shstk: Add Kconfig option for Shadow Stack Rick Edgecombe
2022-02-07 22:39 ` Dave Hansen
2022-02-08 8:41 ` Thomas Gleixner
2022-02-08 20:20 ` Edgecombe, Rick P
2022-02-08 8:39 ` Thomas Gleixner
2022-01-30 21:18 ` [PATCH 03/35] x86/cpufeatures: Add CET CPU feature flags for Control-flow Enforcement Technology (CET) Rick Edgecombe
2022-02-07 22:45 ` Dave Hansen
2022-02-08 20:23 ` Edgecombe, Rick P
2022-02-09 1:10 ` Kees Cook
2022-01-30 21:18 ` [PATCH 04/35] x86/cpufeatures: Introduce CPU setup and option parsing for CET Rick Edgecombe
2022-02-07 22:49 ` Dave Hansen
2022-02-08 20:29 ` Edgecombe, Rick P
2022-01-30 21:18 ` [PATCH 05/35] x86/fpu/xstate: Introduce CET MSR and XSAVES supervisor states Rick Edgecombe
2022-02-07 23:28 ` Dave Hansen
2022-02-08 21:36 ` Edgecombe, Rick P
2022-01-30 21:18 ` [PATCH 06/35] x86/cet: Add control-protection fault handler Rick Edgecombe
2022-02-07 23:56 ` Dave Hansen
2022-02-08 22:23 ` Edgecombe, Rick P
2022-01-30 21:18 ` [PATCH 07/35] x86/mm: Remove _PAGE_DIRTY from kernel RO pages Rick Edgecombe
2022-02-08 0:13 ` Dave Hansen
2022-02-08 22:52 ` Edgecombe, Rick P
2022-01-30 21:18 ` [PATCH 08/35] x86/mm: Move pmd_write(), pud_write() up in the file Rick Edgecombe
2022-01-30 21:18 ` [PATCH 09/35] x86/mm: Introduce _PAGE_COW Rick Edgecombe
2022-02-08 1:05 ` Dave Hansen
2022-01-30 21:18 ` [PATCH 10/35] drm/i915/gvt: Change _PAGE_DIRTY to _PAGE_DIRTY_BITS Rick Edgecombe
2022-02-09 16:58 ` Dave Hansen
2022-02-11 1:39 ` Edgecombe, Rick P
2022-02-11 7:13 ` Wang, Zhi A
2022-02-12 1:45 ` Edgecombe, Rick P
2022-01-30 21:18 ` [PATCH 11/35] x86/mm: Update pte_modify for _PAGE_COW Rick Edgecombe
2022-02-09 18:00 ` Dave Hansen
2022-01-30 21:18 ` [PATCH 12/35] x86/mm: Update ptep_set_wrprotect() and pmdp_set_wrprotect() for transition from _PAGE_DIRTY to _PAGE_COW Rick Edgecombe
2022-02-09 18:30 ` Dave Hansen
2022-01-30 21:18 ` [PATCH 13/35] mm: Move VM_UFFD_MINOR_BIT from 37 to 38 Rick Edgecombe
2022-01-30 21:18 ` [PATCH 14/35] mm: Introduce VM_SHADOW_STACK for shadow stack memory Rick Edgecombe
2022-02-09 21:55 ` Dave Hansen
2022-01-30 21:18 ` [PATCH 15/35] x86/mm: Check Shadow Stack page fault errors Rick Edgecombe
2022-02-09 19:06 ` Dave Hansen
2022-01-30 21:18 ` [PATCH 16/35] x86/mm: Update maybe_mkwrite() for shadow stack Rick Edgecombe
2022-02-09 21:16 ` Dave Hansen
2022-01-30 21:18 ` [PATCH 17/35] mm: Fixup places that call pte_mkwrite() directly Rick Edgecombe
2022-02-09 21:51 ` Dave Hansen
2022-01-30 21:18 ` [PATCH 18/35] mm: Add guard pages around a shadow stack Rick Edgecombe
2022-02-09 22:23 ` Dave Hansen
2022-02-10 22:38 ` David Laight
2022-02-10 23:42 ` Edgecombe, Rick P
2022-02-11 9:08 ` David Laight
2022-02-10 22:43 ` Dave Hansen
2022-02-10 23:07 ` Andy Lutomirski
2022-02-10 23:40 ` Edgecombe, Rick P
2022-02-11 17:54 ` Andy Lutomirski
2022-02-12 0:10 ` Edgecombe, Rick P
2022-01-30 21:18 ` [PATCH 19/35] mm/mmap: Add shadow stack pages to memory accounting Rick Edgecombe
2022-02-09 22:27 ` Dave Hansen
2022-01-30 21:18 ` [PATCH 20/35] mm: Update can_follow_write_pte() for shadow stack Rick Edgecombe
2022-02-09 22:50 ` Dave Hansen
2022-02-09 22:52 ` Dave Hansen
2022-02-10 22:45 ` David Laight
2022-01-30 21:18 ` [PATCH 21/35] mm/mprotect: Exclude shadow stack from preserve_write Rick Edgecombe
2022-02-10 19:27 ` Dave Hansen
2022-01-30 21:18 ` [PATCH 22/35] x86/mm: Prevent VM_WRITE shadow stacks Rick Edgecombe
2022-02-11 22:19 ` Dave Hansen
2022-02-12 1:44 ` Edgecombe, Rick P
2022-01-30 21:18 ` [PATCH 23/35] x86/fpu: Add helpers for modifying supervisor xstate Rick Edgecombe
2022-02-08 8:51 ` Thomas Gleixner
2022-02-09 19:55 ` Edgecombe, Rick P
2022-02-12 0:27 ` Dave Hansen
2022-02-12 2:31 ` Edgecombe, Rick P
2022-01-30 21:18 ` [PATCH 24/35] mm: Re-introduce vm_flags to do_mmap() Rick Edgecombe
2022-01-30 21:18 ` [PATCH 25/35] x86/cet/shstk: Add user-mode shadow stack support Rick Edgecombe
2022-02-11 23:37 ` Dave Hansen
2022-02-12 0:07 ` Andy Lutomirski
2022-02-12 0:11 ` Dave Hansen
2022-02-12 0:12 ` Edgecombe, Rick P
2022-01-30 21:18 ` [PATCH 26/35] x86/process: Change copy_thread() argument 'arg' to 'stack_size' Rick Edgecombe
2022-02-08 8:38 ` Thomas Gleixner
2022-02-11 2:09 ` Edgecombe, Rick P
2022-02-14 12:33 ` Jann Horn
2022-02-15 1:22 ` Edgecombe, Rick P
2022-02-15 8:49 ` Christian Brauner
2022-01-30 21:18 ` [PATCH 27/35] x86/fpu: Add unsafe xsave buffer helpers Rick Edgecombe
2022-01-30 21:18 ` [PATCH 28/35] x86/cet/shstk: Handle thread shadow stack Rick Edgecombe
2022-01-30 21:18 ` [PATCH 29/35] x86/cet/shstk: Introduce shadow stack token setup/verify routines Rick Edgecombe
2022-01-30 21:18 ` [PATCH 30/35] x86/cet/shstk: Handle signals for shadow stack Rick Edgecombe
2022-01-30 21:18 ` [PATCH 31/35] x86/cet/shstk: Add arch_prctl elf feature functions Rick Edgecombe
2022-01-30 21:18 ` [PATCH 32/35] x86/cet/shstk: Introduce map_shadow_stack syscall Rick Edgecombe
2022-01-30 21:18 ` [PATCH 33/35] selftests/x86: Add map_shadow_stack syscall test Rick Edgecombe
2022-02-03 22:42 ` Dave Hansen
2022-02-04 1:22 ` Edgecombe, Rick P
2022-01-30 21:18 ` [PATCH 34/35] x86/cet/shstk: Support wrss for userspace Rick Edgecombe
2022-01-31 7:56 ` Florian Weimer
2022-01-31 18:26 ` H.J. Lu
2022-01-31 18:45 ` Florian Weimer [this message]
2022-01-30 21:18 ` [PATCH 35/35] x86/cpufeatures: Limit shadow stack to Intel CPUs Rick Edgecombe
2022-02-03 21:58 ` John Allen
2022-02-03 22:23 ` H.J. Lu
2022-02-04 22:21 ` John Allen
2022-02-03 21:07 ` [PATCH 00/35] Shadow stacks for userspace Thomas Gleixner
2022-02-04 1:08 ` Edgecombe, Rick P
2022-02-04 5:20 ` Andy Lutomirski
2022-02-04 20:23 ` Edgecombe, Rick P
2022-02-05 13:26 ` David Laight
2022-02-05 13:29 ` H.J. Lu
2022-02-05 20:15 ` Edgecombe, Rick P
2022-02-05 20:21 ` H.J. Lu
2022-02-06 13:19 ` Peter Zijlstra
2022-02-06 13:42 ` David Laight
2022-02-06 13:55 ` H.J. Lu
2022-02-07 10:22 ` Florian Weimer
2022-02-08 1:46 ` Edgecombe, Rick P
2022-02-08 1:31 ` Andy Lutomirski
2022-02-08 9:31 ` Thomas Gleixner
2022-02-08 16:15 ` Andy Lutomirski
2022-02-06 13:06 ` Peter Zijlstra
2022-02-06 18:42 ` Mike Rapoport
2022-02-07 7:20 ` Adrian Reber
2022-02-07 16:30 ` Dave Hansen
2022-02-08 9:16 ` Mike Rapoport
2022-02-08 9:29 ` Cyrill Gorcunov
2022-02-08 16:21 ` Andy Lutomirski
2022-02-08 17:02 ` Cyrill Gorcunov
2022-02-08 21:54 ` Dmitry Safonov
2022-02-09 6:37 ` Cyrill Gorcunov
2022-02-09 2:18 ` Edgecombe, Rick P
2022-02-09 6:43 ` Cyrill Gorcunov
2022-02-09 10:53 ` Mike Rapoport
2022-02-10 2:37 ` Andy Lutomirski
2022-02-10 2:53 ` H.J. Lu
2022-02-10 13:52 ` Willgerodt, Felix
2022-02-11 7:41 ` avagin
2022-02-11 8:04 ` Mike Rapoport
2022-02-28 20:27 ` Mike Rapoport
2022-02-28 20:30 ` Andy Lutomirski
2022-02-28 21:30 ` Mike Rapoport
2022-02-28 22:55 ` Andy Lutomirski
2022-03-03 19:40 ` Mike Rapoport
2022-03-03 23:00 ` Andy Lutomirski
2022-03-04 1:30 ` Edgecombe, Rick P
2022-03-04 19:13 ` Andy Lutomirski
2022-03-07 18:56 ` Mike Rapoport
2022-03-07 19:07 ` H.J. Lu
2022-05-31 11:59 ` Mike Rapoport
2022-05-31 16:25 ` Edgecombe, Rick P
2022-05-31 16:36 ` Mike Rapoport
2022-05-31 17:34 ` Edgecombe, Rick P
2022-05-31 18:00 ` H.J. Lu
2022-06-01 17:27 ` Edgecombe, Rick P
2022-06-01 19:27 ` H.J. Lu
2022-06-01 8:06 ` Mike Rapoport
2022-06-01 17:24 ` Edgecombe, Rick P
2022-06-09 18:04 ` Mike Rapoport
2022-03-07 22:21 ` David Laight
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=87a6fb7nih.fsf@oldenburg.str.redhat.com \
--to=fweimer@redhat.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=eranian@google.com \
--cc=esyr@redhat.com \
--cc=gorcunov@gmail.com \
--cc=hjl.tools@gmail.com \
--cc=hpa@zytor.com \
--cc=jannh@google.com \
--cc=joao.moreira@intel.com \
--cc=john.allen@amd.com \
--cc=kcc@google.com \
--cc=keescook@chromium.org \
--cc=kirill.shutemov@linux.intel.com \
--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=rick.p.edgecombe@intel.com \
--cc=tglx@linutronix.de \
--cc=weijiang.yang@intel.com \
--cc=x86@kernel.org \
/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).