[PATCH v4 13/26] arm64: mte: Validate the PROT_MTE request via arch_validate_flags()
STALE2079d
From: Catalin Marinas <catalin.marinas@arm.com>
Date: 2020-05-15 17:16:58
Also in:
linux-arch, linux-mm
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
Revision v4 of 9 in this series.
Revisions (9)
Make use of the newly introduced arch_validate_flags() hook to sanity-check the PROT_MTE request passed to mmap() and mprotect(). If the mapping does not support MTE, these syscalls will return -EINVAL. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> --- arch/arm64/include/asm/mman.h | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/mman.h b/arch/arm64/include/asm/mman.h
index c77a23869223..5c356d1ca266 100644
--- a/arch/arm64/include/asm/mman.h
+++ b/arch/arm64/include/asm/mman.h@@ -44,7 +44,11 @@ static inline unsigned long arch_calc_vm_flag_bits(unsigned long flags) static inline pgprot_t arch_vm_get_page_prot(unsigned long vm_flags) { - return (vm_flags & VM_MTE) && (vm_flags & VM_MTE_ALLOWED) ? + /* + * Checking for VM_MTE only is sufficient since arch_validate_flags() + * does not permit (VM_MTE & !VM_MTE_ALLOWED). + */ + return (vm_flags & VM_MTE) ? __pgprot(PTE_ATTRINDX(MT_NORMAL_TAGGED)) : __pgprot(0); }
@@ -61,4 +65,14 @@ static inline bool arch_validate_prot(unsigned long prot, unsigned long addr) } #define arch_validate_prot arch_validate_prot +static inline bool arch_validate_flags(unsigned long flags) +{ + if (!system_supports_mte()) + return true; + + /* only allow VM_MTE if VM_MTE_ALLOWED has been set previously */ + return !(flags & VM_MTE) || (flags & VM_MTE_ALLOWED); +} +#define arch_validate_flags arch_validate_flags + #endif /* !__ASM_MMAN_H__ */
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