Fix #78840: imploding $GLOBALS crashes

We add support for IS_INDIRECT zvals to implode().

Author: cmb69

NEWS

@@ -22,6 +22,7 @@ PHP                                                                        NEWS
 - Standard:
   . Fixed bug #78759 (array_search in $GLOBALS). (Nikita)
   . Fixed bug #77638 (var_export'ing certain class instances segfaults). (cmb)
+  . Fixed bug #78840 (imploding $GLOBALS crashes). (cmb)
 
 21 Nov 2019, PHP 7.3.12
 

ext/standard/string.c

@@ -1216,14 +1216,14 @@ PHPAPI void php_implode(const zend_string *glue, zval *pieces, zval *return_valu
 		RETURN_EMPTY_STRING();
 	} else if (numelems == 1) {
 		/* loop to search the first not undefined element... */
-		ZEND_HASH_FOREACH_VAL(Z_ARRVAL_P(pieces), tmp) {
+		ZEND_HASH_FOREACH_VAL_IND(Z_ARRVAL_P(pieces), tmp) {
 			RETURN_STR(zval_get_string(tmp));
 		} ZEND_HASH_FOREACH_END();
 	}
 
 	ptr = strings = do_alloca((sizeof(*strings)) * numelems, use_heap);
 
-	ZEND_HASH_FOREACH_VAL(Z_ARRVAL_P(pieces), tmp) {
+	ZEND_HASH_FOREACH_VAL_IND(Z_ARRVAL_P(pieces), tmp) {
 		if (EXPECTED(Z_TYPE_P(tmp) == IS_STRING)) {
 			ptr->str = Z_STR_P(tmp);
 			len += ZSTR_LEN(ptr->str);

ext/standard/tests/strings/bug78840.phpt

@@ -0,0 +1,10 @@
+--TEST--
+Bug #78840 (imploding $GLOBALS crashes)
+--FILE--
+<?php
+$glue = '';
+@implode($glue, $GLOBALS);
+echo "done\n";
+?>
+--EXPECT--
+done