From: Joerg Roedel <[email protected]> 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.
Signed-off-by: Joerg Roedel <[email protected]> --- drivers/iommu/amd_iommu_v2.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c index d21d4ed..612f7c8 100644 --- a/drivers/iommu/amd_iommu_v2.c +++ b/drivers/iommu/amd_iommu_v2.c @@ -494,6 +494,22 @@ static void handle_fault_error(struct fault *fault) } } +static bool access_error(struct vm_area_struct *vma, struct fault *fault) +{ + unsigned int allowed = 0; + + if (fault->flags & PPR_FAULT_EXEC) + allowed = vma->vm_flags & VM_EXEC; + + if (fault->flags & PPR_FAULT_READ) + allowed = vma->vm_flags & VM_READ; + + if (fault->flags & PPR_FAULT_WRITE) + allowed = vma->vm_flags & VM_WRITE; + + return allowed ? false : true; +} + static void do_fault(struct work_struct *work) { struct fault *fault = container_of(work, struct fault, work); @@ -516,8 +532,8 @@ static void do_fault(struct work_struct *work) goto out; } - if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) { - /* handle_mm_fault would BUG_ON() */ + /* Check if we have the right permissions on the vma */ + if (access_error(vma, fault)) { up_read(&mm->mmap_sem); handle_fault_error(fault); goto out; -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
