IB/hfi: Protect against writable mmap

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 <dennis.dalessandro@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/drivers/infiniband/hw/hfi1/file_ops.c b/drivers/infiniband/hw/hfi1/file_ops.c
index 60598867f94837b1bd80b1c1637ad32fc0011ffd..3d9bce4bfcc7ac26c7b60d5a002881d3face49c9 100644 (file)
--- 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;