Merge tag 'iommu-fixes-v4.4-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu

Pull IOMMU fixes from Joerg Roedel:
 "Two similar fixes for the Intel and AMD IOMMU drivers to add proper
  access checks before calling handle_mm_fault"

* tag 'iommu-fixes-v4.4-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/vt-d: Do access checks before calling handle_mm_fault()
  iommu/amd: Do proper access checking before calling handle_mm_fault()

2 files changed, 38 insertions, 2 deletions

diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index d21d4edf7236..7caf2fa237f2 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 long requested = 0;
+
+        if (fault->flags & PPR_FAULT_EXEC)
+                requested |= VM_EXEC;
+
+        if (fault->flags & PPR_FAULT_READ)
+                requested |= VM_READ;
+
+        if (fault->flags & PPR_FAULT_WRITE)
+                requested |= VM_WRITE;
+
+        return (requested & ~vma->vm_flags) != 0;
+}
+
 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;
diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index c69e3f9ec958..50464833d0b8 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -484,6 +484,23 @@ struct page_req_dsc {
 };
 
 #define PRQ_RING_MASK ((0x1000 << PRQ_ORDER) - 0x10)
+
+static bool access_error(struct vm_area_struct *vma, struct page_req_dsc *req)
+{
+        unsigned long requested = 0;
+
+        if (req->exe_req)
+                requested |= VM_EXEC;
+
+        if (req->rd_req)
+                requested |= VM_READ;
+
+        if (req->wr_req)
+                requested |= VM_WRITE;
+
+        return (requested & ~vma->vm_flags) != 0;
+}
+
 static irqreturn_t prq_event_thread(int irq, void *d)
 {
         struct intel_iommu *iommu = d;
@@ -539,6 +556,9 @@ static irqreturn_t prq_event_thread(int irq, void *d)
                 if (!vma || address < vma->vm_start)
                         goto invalid;
 
+                if (access_error(vma, req))
+                        goto invalid;
+
                 ret = handle_mm_fault(svm->mm, vma, address,
                                       req->wr_req ? FAULT_FLAG_WRITE : 0);
                 if (ret & VM_FAULT_ERROR)