From: "Andy Lutomirski" <luto@kernel.org>
To: "Mike Rapoport" <rppt@kernel.org>
Cc: "Rick P Edgecombe" <rick.p.edgecombe@intel.com>,
"Cyrill Gorcunov" <gorcunov@gmail.com>,
"Balbir Singh" <bsingharora@gmail.com>,
"H. Peter Anvin" <hpa@zytor.com>,
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"Peter Zijlstra (Intel)" <peterz@infradead.org>,
"Randy Dunlap" <rdunlap@infradead.org>,
"Kees Cook" <keescook@chromium.org>,
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"Dave Hansen" <dave.hansen@linux.intel.com>,
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"Shankar, Ravi V" <ravi.v.shankar@intel.com>
Subject: Re: [PATCH 00/35] Shadow stacks for userspace
Date: Mon, 28 Feb 2022 12:30:41 -0800 [thread overview]
Message-ID: <5a792e77-0072-4ded-9f89-e7fcc7f7a1d6@www.fastmail.com> (raw)
In-Reply-To: <Yh0wIMjFdDl8vaNM@kernel.org>
On Mon, Feb 28, 2022, at 12:27 PM, Mike Rapoport wrote:
> On Wed, Feb 09, 2022 at 06:37:53PM -0800, Andy Lutomirski wrote:
>> On 2/8/22 18:18, Edgecombe, Rick P wrote:
>> > On Tue, 2022-02-08 at 20:02 +0300, Cyrill Gorcunov wrote:
>> >
>> > Still wrapping my head around the CRIU save and restore steps, but
>> > another general approach might be to give ptrace the ability to
>> > temporarily pause/resume/set CET enablement and SSP for a stopped
>> > thread. Then injected code doesn't need to jump through any hoops or
>> > possibly run into road blocks. I'm not sure how much this opens things
>> > up if the thread has to be stopped...
>>
>> Hmm, that's maybe not insane.
>>
>> An alternative would be to add a bona fide ptrace call-a-function mechanism.
>> I can think of two potentially usable variants:
>>
>> 1. Straight call. PTRACE_CALL_FUNCTION(addr) just emulates CALL addr,
>> shadow stack push and all.
>>
>> 2. Signal-style. PTRACE_CALL_FUNCTION_SIGFRAME injects an actual signal
>> frame just like a real signal is being delivered with the specified handler.
>> There could be a variant to opt-in to also using a specified altstack and
>> altshadowstack.
>
> Using ptrace() will not solve CRIU's issue with sigreturn because sigreturn
> is called from the victim context rather than from the criu process that
> controls the dump and uses ptrace().
I'm not sure I follow.
>
> Even with the current shadow stack interface Rick proposed, CRIU can restore
> the victim using ptrace without any additional knobs, but we loose an
> important ability to "self-cure" the victim from the parasite in case
> anything goes wrong with criu control process.
>
> Moreover, the issue with backward compatibility is not with ptrace but with
> sigreturn and it seems that criu is not its only user.
So we need an ability for a tracer to cause the tracee to call a function and to return successfully. Apparently a gdb branch can already do this with shstk, and my PTRACE_CALL_FUNCTION_SIGFRAME should also do the trick. I don't see why we need a sigretur-but-dont-verify -- we just need this mechanism to create a frame such that sigreturn actually works.
--Andy
next prev parent reply other threads:[~2022-02-28 20:31 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
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 [this message]
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
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