iommu/amd: Do proper access checking before calling handle_mm_fault()
The handle_mm_fault function expects the caller to do the access checks. Not doing so and calling the function with wrong permissions is a bug (catched by a BUG_ON). So fix this bug by adding proper access checking to the io page-fault code in the AMD IOMMUv2 driver. Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org> Acked-By: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: Joerg Roedel <jroedel@suse.de>
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9f9499ae8e
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7b5cc1a9c9
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@ -494,6 +494,22 @@ static void handle_fault_error(struct fault *fault)
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}
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}
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static bool access_error(struct vm_area_struct *vma, struct fault *fault)
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{
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unsigned long requested = 0;
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if (fault->flags & PPR_FAULT_EXEC)
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requested |= VM_EXEC;
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if (fault->flags & PPR_FAULT_READ)
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requested |= VM_READ;
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if (fault->flags & PPR_FAULT_WRITE)
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requested |= VM_WRITE;
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return (requested & ~vma->vm_flags) != 0;
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}
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static void do_fault(struct work_struct *work)
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{
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struct fault *fault = container_of(work, struct fault, work);
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@ -516,8 +532,8 @@ static void do_fault(struct work_struct *work)
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goto out;
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}
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if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) {
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/* handle_mm_fault would BUG_ON() */
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/* Check if we have the right permissions on the vma */
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if (access_error(vma, fault)) {
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up_read(&mm->mmap_sem);
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handle_fault_error(fault);
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goto out;
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