[SCSI] enclosure: fix oops while iterating enclosure_status array

Based on patch originally by Jeff Mahoney <jeffm@suse.com>

 enclosure_status is expected to be a NULL terminated array of strings
 but isn't actually NULL terminated. When writing an invalid value to
 /sys/class/enclosure/.../.../status, it goes off the end of the array
 and Oopses.


Fix by making the assumption true and adding NULL at the end.
Reported-by: Artur Wojcik <artur.wojcik@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/misc/enclosure.c

@@ -391,6 +391,7 @@ static const char *const enclosure_status [] = {
 	[ENCLOSURE_STATUS_NOT_INSTALLED] = "not installed",
 	[ENCLOSURE_STATUS_UNKNOWN] = "unknown",
 	[ENCLOSURE_STATUS_UNAVAILABLE] = "unavailable",
+	[ENCLOSURE_STATUS_MAX] = NULL,
 };
 
 static const char *const enclosure_type [] = {

include/linux/enclosure.h

@@ -42,6 +42,8 @@ enum enclosure_status {
 	ENCLOSURE_STATUS_NOT_INSTALLED,
 	ENCLOSURE_STATUS_UNKNOWN,
 	ENCLOSURE_STATUS_UNAVAILABLE,
+	/* last element for counting purposes */
+	ENCLOSURE_STATUS_MAX
 };
 
 /* SFF-8485 activity light settings */