From: Catalin Marinas Date: Thu, 20 Feb 2025 15:58:01 +0000 (+0000) Subject: arm64: mte: Do not allow PROT_MTE on MAP_HUGETLB user mappings X-Git-Tag: v5.10.235~151 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=f6100701b3b11fc9f188a8e806fe7b9a0a317790;p=thirdparty%2Fkernel%2Fstable.git 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: # 5.10.x-6.12.x Reported-by: Naresh Kamboju Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/arm64/include/asm/mman.h b/arch/arm64/include/asm/mman.h index 56bc2e4e81a6e..0070ee4ba8955 100644 --- a/arch/arm64/include/asm/mman.h +++ b/arch/arm64/include/asm/mman.h @@ -31,9 +31,12 @@ 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; }