zscanner: remove possible buffer overflow with realpath

src/zscanner/scanner.c.g2

@@ -73128,8 +73128,8 @@ int zs_scanner_parse_file(zs_scanner_t *s,
 	}
 	// Get absolute path of the zone file.
-	if (realpath(file_name, (char*)(s->buffer)) != NULL) {
-		char *full_name = strdup((char*)(s->buffer));
+	char *full_name = realpath(file_name, NULL);
+	if (full_name != NULL) {
 		free(s->path);
 		s->path = strdup(dirname(full_name));
 		free(full_name);

src/zscanner/scanner.c.t0

@@ -7449,8 +7449,8 @@ int zs_scanner_parse_file(zs_scanner_t *s,
 	}
 
 	// Get absolute path of the zone file.
-	if (realpath(file_name, (char*)(s->buffer)) != NULL) {
-		char *full_name = strdup((char*)(s->buffer));
+	char *full_name = realpath(file_name, NULL);
+	if (full_name != NULL) {
 		free(s->path);
 		s->path = strdup(dirname(full_name));
 		free(full_name);

src/zscanner/scanner.rl

@@ -296,8 +296,8 @@ int zs_scanner_parse_file(zs_scanner_t *s,
 	}
 
 	// Get absolute path of the zone file.
-	if (realpath(file_name, (char*)(s->buffer)) != NULL) {
-		char *full_name = strdup((char*)(s->buffer));
+	char *full_name = realpath(file_name, NULL);
+	if (full_name != NULL) {
 		free(s->path);
 		s->path = strdup(dirname(full_name));
 		free(full_name);