scsi: target: consistently null-terminate t10_wwn strings

In preparation for supporting user provided vendor strings, add an extra
byte to the vendor, model and revision arrays in struct t10_wwn. This
ensures that the full INQUIRY data can be carried in the arrays along with
a null-terminator.

Change a number of array readers and writers so that they account for
explicit null-termination:

- The pscsi_set_inquiry_info() and emulate_model_alias_store() codepaths
  don't currently explicitly null-terminate; fix this.

- Existing t10_wwn field dumps use for-loops which step over
  null-terminators for right-padding.
  + Use printf with width specifiers instead.

Signed-off-by: David Disseldorp <ddiss@suse.de>
Reviewed-by: Roman Bolshakov <r.bolshakov@yadro.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

include/target/target_core_base.h

@@ -46,6 +46,10 @@
 /* Used by transport_get_inquiry_vpd_device_ident() */
 #define INQUIRY_VPD_DEVICE_IDENTIFIER_LEN	254
 
+#define INQUIRY_VENDOR_LEN			8
+#define INQUIRY_MODEL_LEN			16
+#define INQUIRY_REVISION_LEN			4
+
 /* Attempts before moving from SHORT to LONG */
 #define PYX_TRANSPORT_WINDOW_CLOSED_THRESHOLD	3
 #define PYX_TRANSPORT_WINDOW_CLOSED_WAIT_SHORT	3  /* In milliseconds */
@@ -315,9 +319,13 @@ struct t10_vpd {
 };
 
 struct t10_wwn {
-	char vendor[8];
-	char model[16];
-	char revision[4];
+	/*
+	 * SCSI left aligned strings may not be null terminated. +1 to ensure a
+	 * null terminator is always present.
+	 */
+	char vendor[INQUIRY_VENDOR_LEN + 1];
+	char model[INQUIRY_MODEL_LEN + 1];
+	char revision[INQUIRY_REVISION_LEN + 1];
 	char unit_serial[INQUIRY_VPD_SERIAL_LEN];
 	spinlock_t t10_vpd_lock;
 	struct se_device *t10_dev;