Fix GHSA-wg4p-4hqh-c3g9

Author: nielsdos

ext/xml/tests/toffset_bounds.phpt

@@ -0,0 +1,42 @@
+--TEST--
+XML_OPTION_SKIP_TAGSTART bounds
+--EXTENSIONS--
+xml
+--FILE--
+<?php
+$sample = "<?xml version=\"1.0\"?><test><child/></test>";
+$parser = xml_parser_create();
+xml_parser_set_option($parser, XML_OPTION_SKIP_TAGSTART, 100);
+$res = xml_parse_into_struct($parser,$sample,$vals,$index);
+var_dump($vals);
+?>
+--EXPECT--
+array(3) {
+  [0]=>
+  array(3) {
+    ["tag"]=>
+    string(0) ""
+    ["type"]=>
+    string(4) "open"
+    ["level"]=>
+    int(1)
+  }
+  [1]=>
+  array(3) {
+    ["tag"]=>
+    string(0) ""
+    ["type"]=>
+    string(8) "complete"
+    ["level"]=>
+    int(2)
+  }
+  [2]=>
+  array(3) {
+    ["tag"]=>
+    string(0) ""
+    ["type"]=>
+    string(5) "close"
+    ["level"]=>
+    int(1)
+  }
+}

ext/xml/xml.c

@@ -657,9 +657,11 @@ void _xml_startElementHandler(void *userData, const XML_Char *name, const XML_Ch
 			array_init(&tag);
 			array_init(&atr);
 
-			_xml_add_to_info(parser, ZSTR_VAL(tag_name) + parser->toffset);
+			char *skipped_tag_name = SKIP_TAGSTART(ZSTR_VAL(tag_name));
 
-			add_assoc_string(&tag, "tag", SKIP_TAGSTART(ZSTR_VAL(tag_name))); /* cast to avoid gcc-warning */
+			_xml_add_to_info(parser, skipped_tag_name);
+
+			add_assoc_string(&tag, "tag", skipped_tag_name);
 			add_assoc_string(&tag, "type", "open");
 			add_assoc_long(&tag, "level", parser->level);
 
@@ -741,12 +743,14 @@ void _xml_endElementHandler(void *userData, const XML_Char *name)
 				add_assoc_string(zv, "type", "complete");
 			}
 		} else {
-			_xml_add_to_info(parser, ZSTR_VAL(tag_name) + parser->toffset);
+			char *skipped_tag_name = SKIP_TAGSTART(ZSTR_VAL(tag_name));
+
+			_xml_add_to_info(parser, skipped_tag_name);
 
 			zval *data = xml_get_separated_data(parser);
 			if (EXPECTED(data)) {
 				array_init(&tag);
-				add_assoc_string(&tag, "tag", SKIP_TAGSTART(ZSTR_VAL(tag_name))); /* cast to avoid gcc-warning */
+				add_assoc_string(&tag, "tag", skipped_tag_name);
 				add_assoc_string(&tag, "type", "close");
 				add_assoc_long(&tag, "level", parser->level);
 				zend_hash_next_index_insert(Z_ARRVAL_P(data), &tag);