IB/hfi: Protect against writable mmap

weiny2 · dledford · commit 12220267645c · 2017-04-28T13:56:23.000-04:00
The device/port status is not intended to be changed from user space.
Prevent a user from mapping them as write or execute.

Reviewed-by: Dennis Dalessandro &lt;dennis.dalessandro@intel.com&gt;
Signed-off-by: Ira Weiny &lt;ira.weiny@intel.com&gt;
Signed-off-by: Dennis Dalessandro &lt;dennis.dalessandro@intel.com&gt;
Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
diff --git a/drivers/infiniband/hw/hfi1/file_ops.c b/drivers/infiniband/hw/hfi1/file_ops.c
@@ -597,6 +597,10 @@ static int hfi1_file_mmap(struct file *fp, struct vm_area_struct *vma)
 		vmf = 1;
 		break;
 	case STATUS:
+		if (flags & (unsigned long)(VM_WRITE | VM_EXEC)) {
+			ret = -EPERM;
+			goto done;
+		}
 		memaddr = kvirt_to_phys((void *)dd->status);
 		memlen = PAGE_SIZE;
 		flags |= VM_IO | VM_DONTEXPAND;
