From: Kees Cook <keescook@chromium.org>
To: Rick Edgecombe <rick.p.edgecombe@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>,
Weijiang Yang <weijiang.yang@intel.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
John Allen <john.allen@amd.com>,
kcc@google.com, eranian@google.com, rppt@kernel.org,
jamorris@linux.microsoft.com, dethoma@microsoft.com,
akpm@linux-foundation.org, Andrew.Cooper3@citrix.com,
christina.schimpe@intel.com, Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: Re: [PATCH v4 29/39] x86/shstk: Handle signals for shadow stack
Date: Fri, 2 Dec 2022 18:46:29 -0800 [thread overview]
Message-ID: <202212021846.AECD42F51@keescook> (raw)
In-Reply-To: <20221203003606.6838-30-rick.p.edgecombe@intel.com>
On Fri, Dec 02, 2022 at 04:35:56PM -0800, Rick Edgecombe wrote:
> From: Yu-cheng Yu <yu-cheng.yu@intel.com>
>
> When a signal is handled normally the context is pushed to the stack
> before handling it. For shadow stacks, since the shadow stack only track's
> return addresses, there isn't any state that needs to be pushed. However,
> there are still a few things that need to be done. These things are
> userspace visible and which will be kernel ABI for shadow stacks.
>
> One is to make sure the restorer address is written to shadow stack, since
> the signal handler (if not changing ucontext) returns to the restorer, and
> the restorer calls sigreturn. So add the restorer on the shadow stack
> before handling the signal, so there is not a conflict when the signal
> handler returns to the restorer.
>
> The other thing to do is to place some type of checkable token on the
> thread's shadow stack before handling the signal and check it during
> sigreturn. This is an extra layer of protection to hamper attackers
> calling sigreturn manually as in SROP-like attacks.
>
> For this token we can use the shadow stack data format defined earlier.
> Have the data pushed be the previous SSP. In the future the sigreturn
> might want to return back to a different stack. Storing the SSP (instead
> of a restore offset or something) allows for future functionality that
> may want to restore to a different stack.
>
> So, when handling a signal push
> - the SSP pointing in the shadow stack data format
> - the restorer address below the restore token.
>
> In sigreturn, verify SSP is stored in the data format and pop the shadow
> stack.
>
> Tested-by: Pengfei Xu <pengfei.xu@intel.com>
> Tested-by: John Allen <john.allen@amd.com>
> Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
next prev parent reply other threads:[~2022-12-03 2:46 UTC|newest]
Thread overview: 107+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-03 0:35 [PATCH v4 00/39] Shadow stacks for userspace Rick Edgecombe
2022-12-03 0:35 ` [PATCH v4 01/39] Documentation/x86: Add CET shadow stack description Rick Edgecombe
2022-12-03 2:20 ` Kees Cook
2022-12-03 8:58 ` Bagas Sanjaya
2022-12-05 21:20 ` Edgecombe, Rick P
2022-12-03 0:35 ` [PATCH v4 02/39] x86/shstk: Add Kconfig option for Shadow Stack Rick Edgecombe
2022-12-03 2:20 ` Kees Cook
2022-12-03 0:35 ` [PATCH v4 03/39] x86/cpufeatures: Add CPU feature flags for shadow stacks Rick Edgecombe
2022-12-03 2:22 ` Kees Cook
2022-12-07 11:00 ` Borislav Petkov
2022-12-07 22:35 ` Edgecombe, Rick P
2022-12-08 11:10 ` Borislav Petkov
2022-12-03 0:35 ` [PATCH v4 04/39] x86/cpufeatures: Enable CET CR4 bit for shadow stack Rick Edgecombe
2022-12-03 2:23 ` Kees Cook
2022-12-07 12:49 ` Borislav Petkov
2022-12-07 18:35 ` Edgecombe, Rick P
2022-12-03 0:35 ` [PATCH v4 05/39] x86/fpu/xstate: Introduce CET MSR and XSAVES supervisor states Rick Edgecombe
2022-12-03 2:24 ` Kees Cook
2022-12-20 11:32 ` Borislav Petkov
2022-12-21 0:45 ` Edgecombe, Rick P
2022-12-03 0:35 ` [PATCH v4 06/39] x86/fpu: Add helper for modifying xstate Rick Edgecombe
2022-12-03 2:25 ` Kees Cook
2022-12-20 12:04 ` Borislav Petkov
2022-12-21 0:03 ` Edgecombe, Rick P
2022-12-21 10:31 ` Borislav Petkov
2022-12-03 0:35 ` [PATCH v4 07/39] x86: Add user control-protection fault handler Rick Edgecombe
2022-12-03 2:28 ` Kees Cook
2022-12-20 16:19 ` Borislav Petkov
2022-12-21 0:37 ` Edgecombe, Rick P
2022-12-21 10:41 ` Borislav Petkov
2022-12-21 21:42 ` Edgecombe, Rick P
2023-01-04 12:50 ` Borislav Petkov
2022-12-20 21:21 ` Borislav Petkov
2022-12-21 0:38 ` Edgecombe, Rick P
2022-12-03 0:35 ` [PATCH v4 08/39] x86/mm: Remove _PAGE_DIRTY from kernel RO pages Rick Edgecombe
2022-12-03 2:29 ` Kees Cook
2022-12-20 19:11 ` Borislav Petkov
2022-12-03 0:35 ` [PATCH v4 09/39] x86/mm: Move pmd_write(), pud_write() up in the file Rick Edgecombe
2022-12-03 0:35 ` [PATCH v4 10/39] x86/mm: Introduce _PAGE_COW Rick Edgecombe
2022-12-03 2:31 ` Kees Cook
2022-12-20 21:29 ` Borislav Petkov
2022-12-21 0:45 ` Edgecombe, Rick P
2022-12-03 0:35 ` [PATCH v4 11/39] x86/mm: Update pte_modify for _PAGE_COW Rick Edgecombe
2022-12-03 2:31 ` Kees Cook
2022-12-27 11:42 ` Borislav Petkov
2022-12-27 23:31 ` Edgecombe, Rick P
2023-01-04 13:25 ` Borislav Petkov
2023-01-05 1:06 ` Edgecombe, Rick P
2022-12-03 0:35 ` [PATCH v4 12/39] x86/mm: Update ptep_set_wrprotect() and pmdp_set_wrprotect() for transition from _PAGE_DIRTY to _PAGE_COW Rick Edgecombe
2022-12-03 2:32 ` Kees Cook
2022-12-27 13:26 ` Borislav Petkov
2022-12-27 22:26 ` Edgecombe, Rick P
2023-01-04 13:28 ` Borislav Petkov
2022-12-03 0:35 ` [PATCH v4 13/39] x86/mm: Start actually marking _PAGE_COW Rick Edgecombe
2022-12-03 2:33 ` Kees Cook
2022-12-03 0:35 ` [PATCH v4 14/39] mm: Move VM_UFFD_MINOR_BIT from 37 to 38 Rick Edgecombe
2022-12-03 0:35 ` [PATCH v4 15/39] mm: Introduce VM_SHADOW_STACK for shadow stack memory Rick Edgecombe
2022-12-03 2:34 ` Kees Cook
2022-12-03 0:35 ` [PATCH v4 16/39] x86/mm: Check Shadow Stack page fault errors Rick Edgecombe
2023-01-04 14:32 ` Borislav Petkov
2023-01-05 1:29 ` Edgecombe, Rick P
2022-12-03 0:35 ` [PATCH v4 17/39] x86/mm: Update maybe_mkwrite() for shadow stack Rick Edgecombe
2022-12-03 2:34 ` Kees Cook
2022-12-03 0:35 ` [PATCH v4 18/39] mm: Fixup places that call pte_mkwrite() directly Rick Edgecombe
2022-12-03 2:37 ` Kees Cook
2022-12-03 0:35 ` [PATCH v4 19/39] mm: Add guard pages around a shadow stack Rick Edgecombe
2022-12-03 0:35 ` [PATCH v4 20/39] mm/mmap: Add shadow stack pages to memory accounting Rick Edgecombe
2022-12-03 2:38 ` Kees Cook
2022-12-03 0:35 ` [PATCH v4 21/39] mm/mprotect: Exclude shadow stack from preserve_write Rick Edgecombe
2022-12-03 2:38 ` Kees Cook
2022-12-03 0:35 ` [PATCH v4 22/39] mm: Re-introduce vm_flags to do_mmap() Rick Edgecombe
2022-12-03 0:35 ` [PATCH v4 23/39] mm: Don't allow write GUPs to shadow stack memory Rick Edgecombe
2022-12-03 2:39 ` Kees Cook
2022-12-03 0:35 ` [PATCH v4 24/39] mm: Warn on shadow stack memory in wrong vma Rick Edgecombe
2022-12-03 2:40 ` Kees Cook
2022-12-03 0:35 ` [PATCH v4 25/39] x86: Introduce userspace API for shadow stack Rick Edgecombe
2022-12-03 2:42 ` Kees Cook
2022-12-03 0:35 ` [PATCH v4 26/39] x86/shstk: Add user-mode shadow stack support Rick Edgecombe
2022-12-03 2:43 ` Kees Cook
2022-12-03 0:35 ` [PATCH v4 27/39] x86/shstk: Handle thread shadow stack Rick Edgecombe
2022-12-03 2:44 ` Kees Cook
2022-12-03 0:35 ` [PATCH v4 28/39] x86/shstk: Introduce routines modifying shstk Rick Edgecombe
2022-12-03 2:45 ` Kees Cook
2022-12-03 0:35 ` [PATCH v4 29/39] x86/shstk: Handle signals for shadow stack Rick Edgecombe
2022-12-03 2:46 ` Kees Cook [this message]
2022-12-03 0:35 ` [PATCH v4 30/39] x86/shstk: Introduce map_shadow_stack syscall Rick Edgecombe
2022-12-03 2:51 ` Kees Cook
2022-12-05 22:19 ` Edgecombe, Rick P
2022-12-03 0:35 ` [PATCH v4 31/39] x86/shstk: Support wrss for userspace Rick Edgecombe
2022-12-03 2:52 ` Kees Cook
2022-12-03 0:35 ` [PATCH v4 32/39] x86: Expose thread features in /proc/$PID/status Rick Edgecombe
2022-12-03 2:52 ` Kees Cook
2022-12-03 0:36 ` [PATCH v4 33/39] x86: Prevent 32 bit operations for 64 bit shstk tasks Rick Edgecombe
2022-12-03 22:49 ` Andy Lutomirski
2022-12-04 20:51 ` Edgecombe, Rick P
2022-12-15 0:25 ` Edgecombe, Rick P
2022-12-03 0:36 ` [PATCH v4 34/39] x86/shstk: Wire in shadow stack interface Rick Edgecombe
2022-12-03 0:36 ` [PATCH v4 35/39] selftests/x86: Add shadow stack test Rick Edgecombe
2022-12-03 0:36 ` [PATCH v4 36/39] x86/fpu: Add helper for initing features Rick Edgecombe
2022-12-03 0:36 ` [PATCH v4 37/39] x86: Add PTRACE interface for shadow stack Rick Edgecombe
2022-12-03 2:55 ` Kees Cook
2022-12-09 17:04 ` Mike Rapoport
2022-12-09 17:08 ` Edgecombe, Rick P
2022-12-03 0:36 ` [PATCH v4 38/39] x86/shstk: Add ARCH_SHSTK_UNLOCK Rick Edgecombe
2022-12-03 2:56 ` Kees Cook
2022-12-03 0:36 ` [PATCH v4 39/39] x86/shstk: Add ARCH_SHSTK_STATUS Rick Edgecombe
2022-12-03 2:57 ` Kees Cook
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