linux-kernel - [PATCH 1/3] libnvdimm, region : make 'resource' attribute only readable by root

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Date:   Tue, 26 Sep 2017 15:57:15 -0700
From:   Dan Williams <dan.j.williams@...el.com>
To:     linux-nvdimm@...ts.01.org
Cc:     Dave Hansen <dave.hansen@...ux.intel.com>,
        Dave Jiang <dave.jiang@...el.com>,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Johannes Thumshirn <jthumshirn@...e.de>
Subject: [PATCH 1/3] 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@...r.kernel.org>
Cc: Dave Jiang <dave.jiang@...el.com>
Cc: Johannes Thumshirn <jthumshirn@...e.de>
Reported-by: Dave Hansen <dave.hansen@...ux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@...el.com>
---
 drivers/nvdimm/region_devs.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index 829d760f651c..abaf38c61220 100644
--- 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);