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authorJoerg Roedel2015-11-17 16:11:36 +0100
committerJoerg Roedel2015-12-14 15:37:47 +0100
commit7b5cc1a9c9f4096555345c365508d727149553fe (patch)
treea704d1bec65c7bda54af3dffbeca97feeb09c57c /drivers/iommu
parent9f9499ae8e6415cefc4fe0a96ad0e27864353c89 (diff)
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>
Diffstat (limited to 'drivers/iommu')
-rw-r--r--drivers/iommu/amd_iommu_v2.c20
1 files changed, 18 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;