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Date:   Sun, 22 Jan 2023 10:20:27 +0200
From:   Mike Rapoport <rppt@kernel.org>
To:     Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc:     x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
        Thomas Gleixner <tglx@linutronix.de>,
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        Arnd Bergmann <arnd@arndb.de>,
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        Balbir Singh <bsingharora@gmail.com>,
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        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,
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        Andrew.Cooper3@citrix.com, christina.schimpe@intel.com
Subject: Re: [PATCH v5 00/39] Shadow stacks for userspace
Message-ID: <Y8zxy4uVId8xlY1G@kernel.org>
References: <20230119212317.8324-1-rick.p.edgecombe@intel.com>
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In-Reply-To: <20230119212317.8324-1-rick.p.edgecombe@intel.com>
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On Thu, Jan 19, 2023 at 01:22:38PM -0800, Rick Edgecombe wrote:
> Hi,
> 
> This series implements Shadow Stacks for userspace using x86's Control-flow 
> Enforcement Technology (CET). CET consists of two related security features: 
> shadow stacks and indirect branch tracking. This series implements just the 
> shadow stack part of this feature, and just for userspace.

Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>

> Previous version [1].
> 
> [0] https://lore.kernel.org/lkml/20220130211838.8382-1-rick.p.edgecombe@intel.com/
> [1] https://lore.kernel.org/lkml/20221203003606.6838-1-rick.p.edgecombe@intel.com/
> 
> Kirill A. Shutemov (1):
>   x86: Introduce userspace API for shadow stack
> 
> Mike Rapoport (1):
>   x86/shstk: Add ARCH_SHSTK_UNLOCK
> 
> Rick Edgecombe (14):
>   x86/fpu: Add helper for modifying xstate
>   x86/mm: Introduce _PAGE_COW
>   x86/mm: Start actually marking _PAGE_COW
>   mm: Handle faultless write upgrades for shstk
>   mm: Don't allow write GUPs to shadow stack memory
>   x86/mm: Introduce MAP_ABOVE4G
>   mm: Warn on shadow stack memory in wrong vma
>   x86/shstk: Introduce map_shadow_stack syscall
>   x86/shstk: Support WRSS for userspace
>   x86: Expose thread features in /proc/$PID/status
>   x86/shstk: Wire in shadow stack interface
>   selftests/x86: Add shadow stack test
>   x86/fpu: Add helper for initing features
>   x86/shstk: Add ARCH_SHSTK_STATUS
> 
> Yu-cheng Yu (23):
>   Documentation/x86: Add CET shadow stack description
>   x86/shstk: Add Kconfig option for shadow stack
>   x86/cpufeatures: Add CPU feature flags for shadow stacks
>   x86/cpufeatures: Enable CET CR4 bit for shadow stack
>   x86/fpu/xstate: Introduce CET MSR and XSAVES supervisor states
>   x86: Add user control-protection fault handler
>   x86/mm: Remove _PAGE_DIRTY from kernel RO pages
>   x86/mm: Move pmd_write(), pud_write() up in the file
>   x86/mm: Update pte_modify for _PAGE_COW
>   x86/mm: Update ptep_set_wrprotect() and pmdp_set_wrprotect() for
>     transition from _PAGE_DIRTY to _PAGE_COW
>   mm: Move VM_UFFD_MINOR_BIT from 37 to 38
>   mm: Introduce VM_SHADOW_STACK for shadow stack memory
>   x86/mm: Check shadow stack page fault errors
>   x86/mm: Update maybe_mkwrite() for shadow stack
>   mm: Fixup places that call pte_mkwrite() directly
>   mm: Add guard pages around a shadow stack.
>   mm/mmap: Add shadow stack pages to memory accounting
>   mm: Re-introduce vm_flags to do_mmap()
>   x86/shstk: Add user-mode shadow stack support
>   x86/shstk: Handle thread shadow stack
>   x86/shstk: Introduce routines modifying shstk
>   x86/shstk: Handle signals for shadow stack
>   x86: Add PTRACE interface for shadow stack
> 
>  Documentation/filesystems/proc.rst            |   1 +
>  Documentation/x86/index.rst                   |   1 +
>  Documentation/x86/shstk.rst                   | 176 +++++
>  arch/arm/kernel/signal.c                      |   2 +-
>  arch/arm64/kernel/signal.c                    |   2 +-
>  arch/arm64/kernel/signal32.c                  |   2 +-
>  arch/sparc/kernel/signal32.c                  |   2 +-
>  arch/sparc/kernel/signal_64.c                 |   2 +-
>  arch/x86/Kconfig                              |  24 +
>  arch/x86/Kconfig.assembler                    |   5 +
>  arch/x86/entry/syscalls/syscall_64.tbl        |   1 +
>  arch/x86/include/asm/cpufeatures.h            |   2 +
>  arch/x86/include/asm/disabled-features.h      |  16 +-
>  arch/x86/include/asm/fpu/api.h                |   9 +
>  arch/x86/include/asm/fpu/regset.h             |   7 +-
>  arch/x86/include/asm/fpu/sched.h              |   3 +-
>  arch/x86/include/asm/fpu/types.h              |  16 +-
>  arch/x86/include/asm/fpu/xstate.h             |   6 +-
>  arch/x86/include/asm/idtentry.h               |   2 +-
>  arch/x86/include/asm/mmu_context.h            |   2 +
>  arch/x86/include/asm/msr.h                    |  11 +
>  arch/x86/include/asm/pgtable.h                | 338 ++++++++-
>  arch/x86/include/asm/pgtable_types.h          |  65 +-
>  arch/x86/include/asm/processor.h              |   8 +
>  arch/x86/include/asm/shstk.h                  |  40 ++
>  arch/x86/include/asm/special_insns.h          |  13 +
>  arch/x86/include/asm/tlbflush.h               |   3 +-
>  arch/x86/include/asm/trap_pf.h                |   2 +
>  arch/x86/include/asm/traps.h                  |  12 +
>  arch/x86/include/uapi/asm/mman.h              |   4 +
>  arch/x86/include/uapi/asm/prctl.h             |  12 +
>  arch/x86/kernel/Makefile                      |   4 +
>  arch/x86/kernel/cet.c                         | 152 ++++
>  arch/x86/kernel/cpu/common.c                  |  35 +-
>  arch/x86/kernel/cpu/cpuid-deps.c              |   1 +
>  arch/x86/kernel/cpu/proc.c                    |  23 +
>  arch/x86/kernel/fpu/core.c                    |  59 +-
>  arch/x86/kernel/fpu/regset.c                  |  87 +++
>  arch/x86/kernel/fpu/xstate.c                  | 148 ++--
>  arch/x86/kernel/fpu/xstate.h                  |   6 +
>  arch/x86/kernel/idt.c                         |   2 +-
>  arch/x86/kernel/process.c                     |  18 +-
>  arch/x86/kernel/process_64.c                  |   9 +-
>  arch/x86/kernel/ptrace.c                      |  12 +
>  arch/x86/kernel/shstk.c                       | 492 +++++++++++++
>  arch/x86/kernel/signal.c                      |   1 +
>  arch/x86/kernel/signal_32.c                   |   2 +-
>  arch/x86/kernel/signal_64.c                   |   8 +-
>  arch/x86/kernel/sys_x86_64.c                  |   6 +-
>  arch/x86/kernel/traps.c                       |  87 ---
>  arch/x86/mm/fault.c                           |  38 +
>  arch/x86/mm/pat/set_memory.c                  |   2 +-
>  arch/x86/mm/pgtable.c                         |   6 +
>  arch/x86/xen/enlighten_pv.c                   |   2 +-
>  arch/x86/xen/xen-asm.S                        |   2 +-
>  fs/aio.c                                      |   2 +-
>  fs/proc/array.c                               |   6 +
>  fs/proc/task_mmu.c                            |   3 +
>  include/linux/mm.h                            |  59 +-
>  include/linux/mman.h                          |   4 +
>  include/linux/pgtable.h                       |  35 +
>  include/linux/proc_fs.h                       |   2 +
>  include/linux/syscalls.h                      |   1 +
>  include/uapi/asm-generic/siginfo.h            |   3 +-
>  include/uapi/asm-generic/unistd.h             |   2 +-
>  include/uapi/linux/elf.h                      |   2 +
>  ipc/shm.c                                     |   2 +-
>  kernel/sys_ni.c                               |   1 +
>  mm/gup.c                                      |   2 +-
>  mm/huge_memory.c                              |  12 +-
>  mm/memory.c                                   |   7 +-
>  mm/migrate_device.c                           |   4 +-
>  mm/mmap.c                                     |  12 +-
>  mm/nommu.c                                    |   4 +-
>  mm/userfaultfd.c                              |  10 +-
>  mm/util.c                                     |   2 +-
>  tools/testing/selftests/x86/Makefile          |   4 +-
>  .../testing/selftests/x86/test_shadow_stack.c | 667 ++++++++++++++++++
>  78 files changed, 2578 insertions(+), 259 deletions(-)
>  create mode 100644 Documentation/x86/shstk.rst
>  create mode 100644 arch/x86/include/asm/shstk.h
>  create mode 100644 arch/x86/kernel/cet.c
>  create mode 100644 arch/x86/kernel/shstk.c
>  create mode 100644 tools/testing/selftests/x86/test_shadow_stack.c
> 
> -- 
> 2.17.1
>