ima/policy: fix parsing of fsuuid

The switch to uuid_t invereted the logic of verfication that &entry->fsuuid
is zero during parsing of "fsuuid=" rule. Instead of making sure the
&entry->fsuuid field is not attempted to be overwritten, we bail out for
perfectly correct rule.

Fixes: 787d8c530a ("ima/policy: switch to use uuid_t")

Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>

security/integrity/ima/ima_policy.c

@@ -765,7 +765,7 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 		case Opt_fsuuid:
 			ima_log_string(ab, "fsuuid", args[0].from);
 
-			if (uuid_is_null(&entry->fsuuid)) {
+			if (!uuid_is_null(&entry->fsuuid)) {
 				result = -EINVAL;
 				break;
 			}