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arm64: mte: Validate the PROT_MTE request via arch_validate_flags() 

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>
This commit is contained in:
Catalin Marinas 2019-08-09 15:48:46 +01:00
parent c462ac288f
commit 0042090548
1 changed files with 13 additions and 1 deletions
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14
arch/arm64/include/asm/mman.h
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@ -49,8 +49,10 @@ static inline pgprot_t arch_vm_get_page_prot(unsigned long vm_flags)
* register (1) as VM_MTE in the vma->vm_flags and (2) as
* VM_MTE_ALLOWED. Note that the latter can only be set during the
* mmap() call since mprotect() does not accept MAP_* flags.
* Checking for VM_MTE only is sufficient since arch_validate_flags()
* does not permit (VM_MTE & !VM_MTE_ALLOWED).
*/
if ((vm_flags & VM_MTE) && (vm_flags & VM_MTE_ALLOWED))
if (vm_flags & VM_MTE)
prot |= PTE_ATTRINDX(MT_NORMAL_TAGGED);
return __pgprot(prot);
@ -72,4 +74,14 @@ static inline bool arch_validate_prot(unsigned long prot,
}
#define arch_validate_prot(prot, addr) arch_validate_prot(prot, addr)
static inline bool arch_validate_flags(unsigned long vm_flags)
{
if (!system_supports_mte())
return true;
/* only allow VM_MTE if VM_MTE_ALLOWED has been set previously */
return !(vm_flags & VM_MTE) || (vm_flags & VM_MTE_ALLOWED);
}
#define arch_validate_flags(vm_flags) arch_validate_flags(vm_flags)
#endif /* ! __ASM_MMAN_H__ */