From: NeilBrown <neilb@suse.de>

The ioctl requires CAP_SYS_ADMIN, so sysfs should too.  Note that we don't
require CAP_SYS_ADMIN for reading attributes even though the ioctl does. 
There is no reason to limit the read access, and much of the information is
already available via /proc/mdstat

Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 drivers/md/md.c |    4 ++++
 1 file changed, 4 insertions(+)

diff -puN drivers/md/md.c~md-require-cap_sys_admin-for-re-configuring-md-devices-via-sysfs drivers/md/md.c
--- a/drivers/md/md.c~md-require-cap_sys_admin-for-re-configuring-md-devices-via-sysfs
+++ a/drivers/md/md.c
@@ -1928,6 +1928,8 @@ rdev_attr_store(struct kobject *kobj, st
 
 	if (!entry->store)
 		return -EIO;
+	if (!capable(CAP_SYS_ADMIN))
+		return -EACCES;
 	return entry->store(rdev, page, length);
 }
 
@@ -2861,6 +2863,8 @@ md_attr_store(struct kobject *kobj, stru
 
 	if (!entry->store)
 		return -EIO;
+	if (!capable(CAP_SYS_ADMIN))
+		return -EACCES;
 	rv = mddev_lock(mddev);
 	if (!rv) {
 		rv = entry->store(mddev, page, length);
_