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| author | Catalin Marinas <catalin.marinas@arm.com> | 2025-02-20 18:58:01 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-02-27 15:30:13 +0300 |
| commit | 93745f5f2377c6e12e1607bcb8558b9f0b673483 (patch) | |
| tree | f4e35a29053ea5add7e5d03582870290bb85d46f | |
| parent | 19b4657de424f48a588eb379fe3214d317f46cd7 (diff) | |
| download | linux-93745f5f2377c6e12e1607bcb8558b9f0b673483.tar.xz | |
arm64: mte: Do not allow PROT_MTE on MAP_HUGETLB user mappings
PROT_MTE (memory tagging extensions) is not supported on all user mmap()
types for various reasons (memory attributes, backing storage, CoW
handling). The arm64 arch_validate_flags() function checks whether the
VM_MTE_ALLOWED flag has been set for a vma during mmap(), usually by
arch_calc_vm_flag_bits().
Linux prior to 6.13 does not support PROT_MTE hugetlb mappings. This was
added by commit 25c17c4b55de ("hugetlb: arm64: add mte support").
However, earlier kernels inadvertently set VM_MTE_ALLOWED on
(MAP_ANONYMOUS | MAP_HUGETLB) mappings by only checking for
MAP_ANONYMOUS.
Explicitly check MAP_HUGETLB in arch_calc_vm_flag_bits() and avoid
setting VM_MTE_ALLOWED for such mappings.
Fixes: 9f3419315f3c ("arm64: mte: Add PROT_MTE support to mmap() and mprotect()")
Cc: <stable@vger.kernel.org> # 5.10.x-6.12.x
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/arm64/include/asm/mman.h | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/arm64/include/asm/mman.h b/arch/arm64/include/asm/mman.h index 798d965760d4..5a280ac7570c 100644 --- a/arch/arm64/include/asm/mman.h +++ b/arch/arm64/include/asm/mman.h @@ -41,9 +41,12 @@ static inline unsigned long arch_calc_vm_flag_bits(struct file *file, * backed by tags-capable memory. The vm_flags may be overridden by a * filesystem supporting MTE (RAM-based). */ - if (system_supports_mte() && - ((flags & MAP_ANONYMOUS) || shmem_file(file))) - return VM_MTE_ALLOWED; + if (system_supports_mte()) { + if ((flags & MAP_ANONYMOUS) && !(flags & MAP_HUGETLB)) + return VM_MTE_ALLOWED; + if (shmem_file(file)) + return VM_MTE_ALLOWED; + } return 0; } |