NetLabel: correct CIPSO tag handling when adding new DOI definitions

The current netlbl_cipsov4_add_common() function has two problems which are
fixed with this patch.  The first is an off-by-one bug where it is possibile to
overflow the doi_def->tags[] array.  The second is a bug where the same
doi_def->tags[] array was not always fully initialized, which caused sporadic
failures.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: James Morris <jmorris@namei.org>

net/netlabel/netlabel_cipso_v4.c

@@ -130,12 +130,12 @@ static int netlbl_cipsov4_add_common(struct genl_info *info,
 
 	nla_for_each_nested(nla, info->attrs[NLBL_CIPSOV4_A_TAGLST], nla_rem)
 		if (nla->nla_type == NLBL_CIPSOV4_A_TAG) {
-			if (iter > CIPSO_V4_TAG_MAXCNT)
+			if (iter >= CIPSO_V4_TAG_MAXCNT)
 				return -EINVAL;
 			doi_def->tags[iter++] = nla_get_u8(nla);
 		}
-	if (iter < CIPSO_V4_TAG_MAXCNT)
-		doi_def->tags[iter] = CIPSO_V4_TAG_INVALID;
+	while (iter < CIPSO_V4_TAG_MAXCNT)
+		doi_def->tags[iter++] = CIPSO_V4_TAG_INVALID;
 
 	return 0;
 }