[PATCH 4.4 48/96] libnvdimm, namespace: make resource attribute only readable by root

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dan Williams <dan.j.williams@xxxxxxxxx>

commit c1fb3542074fd0c4d901d778bd52455111e4eb6f upstream.

For the same reason that /proc/iomem returns 0's for non-root readers
and acpi tables are root-only, make the 'resource' attribute for
namespace devices only readable by root. Otherwise we disclose physical
address information.

Fixes: bf9bccc14c05 ("libnvdimm: pmem label sets and namespace instantiation")
Reported-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/nvdimm/namespace_devs.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -1305,7 +1305,7 @@ static umode_t namespace_visible(struct
 	if (a == &dev_attr_resource.attr) {
 		if (is_namespace_blk(dev))
 			return 0;
-		return a->mode;
+		return 0400;
 	}
 
 	if (is_namespace_pmem(dev) || is_namespace_blk(dev)) {