libnvdimm, region : make 'resource' attribute only readable by root

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 region
devices only readable by root. Otherwise we disclose physical address
information.

Fixes: 802f4be6feee ("libnvdimm: Add 'resource' sysfs attribute to regions")
Cc: <stable@vger.kernel.org>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Reported-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index 829d760f651c7f86e86ed4b8a3f212d3b6ee0a05..abaf38c612206803fb065852159968948226362a 100644 (file)
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -562,8 +562,12 @@ static umode_t region_visible(struct kobject *kobj, struct attribute *a, int n)
        if (!is_nd_pmem(dev) && a == &dev_attr_badblocks.attr)
                return 0;
 
-       if (!is_nd_pmem(dev) && a == &dev_attr_resource.attr)
-               return 0;
+       if (a == &dev_attr_resource.attr) {
+               if (is_nd_pmem(dev))
+                       return 0400;
+               else
+                       return 0;
+       }
 
        if (a == &dev_attr_deep_flush.attr) {
                int has_flush = nvdimm_has_flush(nd_region);