Re: [PATCH v26 29/30] mm: Update arch_validate_flags() to test vma anonymous
From: Kirill A. Shutemov <hidden>
Date: 2021-05-11 11:35:43
Also in:
linux-arch, linux-doc, linux-mm, lkml
On Tue, Apr 27, 2021 at 01:43:14PM -0700, Yu-cheng Yu wrote:
When newer VM flags are being created, such as VM_MTE, it becomes necessary
for mmap/mprotect to verify if certain flags are being applied to an
anonymous VMA.
To solve this, one approach is adding a VM flag to track that MAP_ANONYMOUS
is specified [1], and then using the flag in arch_validate_flags().
Another approach is passing the VMA to arch_validate_flags(), and check
vma_is_anonymous().
To prepare the introduction of PROT_SHADOW_STACK, which creates a shadow
stack mapping and can be applied only to an anonymous VMA, update
arch_validate_flags() to pass in the VMA.
[1] commit 9f3419315f3c ("arm64: mte: Add PROT_MTE support to mmap() and mprotect()"),
Signed-off-by: Yu-cheng Yu <redacted>Reviewed-by: Kirill A. Shutemov <redacted> -- Kirill A. Shutemov