On Mon, Feb 24, 2025 at 10:52:42PM +0000, jef...@chromium.org wrote:
> From: Jeff Xu <jef...@chromium.org>
> 
> Provide support for CONFIG_MSEAL_SYSTEM_MAPPINGS on x86-64,
> covering the vdso, vvar, vvar_vclock.
> 
> Production release testing passes on Android and Chrome OS.
> 
> Signed-off-by: Jeff Xu <jef...@chromium.org>
> ---
>  arch/x86/Kconfig          |  1 +
>  arch/x86/entry/vdso/vma.c | 16 ++++++++++------
>  2 files changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 87198d957e2f..8fa17032ca46 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -26,6 +26,7 @@ config X86_64
>       depends on 64BIT
>       # Options that are inherently 64-bit kernel only:
>       select ARCH_HAS_GIGANTIC_PAGE
> +     select ARCH_HAS_MSEAL_SYSTEM_MAPPINGS
>       select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
>       select ARCH_SUPPORTS_PER_VMA_LOCK
>       select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE
> diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
> index 39e6efc1a9ca..1b1c009f20a8 100644
> --- a/arch/x86/entry/vdso/vma.c
> +++ b/arch/x86/entry/vdso/vma.c
> @@ -247,6 +247,7 @@ static int map_vdso(const struct vdso_image *image, 
> unsigned long addr)
>       struct mm_struct *mm = current->mm;
>       struct vm_area_struct *vma;
>       unsigned long text_start;
> +     unsigned long vm_flags;
>       int ret = 0;
>  
>       if (mmap_write_lock_killable(mm))
> @@ -264,11 +265,12 @@ static int map_vdso(const struct vdso_image *image, 
> unsigned long addr)
>       /*
>        * MAYWRITE to allow gdb to COW and set breakpoints
>        */
> +     vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC;
> +     vm_flags |= VM_SEALED_SYSMAP;
>       vma = _install_special_mapping(mm,
>                                      text_start,
>                                      image->size,
> -                                    VM_READ|VM_EXEC|
> -                                    VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
> +                                    vm_flags,
>                                      &vdso_mapping);

I think these (in all patches) were supposed to be reworked without the
"vm_flags" variable addition?

-- 
Kees Cook

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