Fix segfault comparing uninitialized SimpleXMLElement instances

.github/scripts/windows/test_task.bat

@@ -117,8 +117,9 @@ set PHP_BUILD_DIR=%PHP_BUILD_OBJ_DIR%\Release
 if "%THREAD_SAFE%" equ "1" set PHP_BUILD_DIR=%PHP_BUILD_DIR%_TS
 
 rem prepare for mail
-curl -sLo hMailServer.exe https://www.hmailserver.com/download_file/?downloadid=271
-hMailServer.exe /verysilent
+curl -sLo hMailServer.zip https://downloads.php.net/~windows/php-sdk/deps/vs18/x64/hmailserver-5.7.0-vs18-x64.zip
+unzip -q hMailServer.zip -d hMailServer
+hMailServer\bin\hMailServer.exe /verysilent
 cd %APPVEYOR_BUILD_FOLDER%
 %PHP_BUILD_DIR%\php.exe -dextension_dir=%PHP_BUILD_DIR% -dextension=com_dotnet .github\setup_hmailserver.php
 

NEWS

@@ -37,6 +37,15 @@ PHP                                                                        NEWS
   . Fixed segfault in ReflectionMethod::createFromMethodName() on an
     uninstantiable subclass. (iliaal)
 
+- Session:
+  . Fix corruption in mod_mm. (ndossche)
+  . Fixed bug GH-23043 (broken session id code can cause zend_mm_heap
+    corrupted). (ndossche)
+
+- SimpleXML:
+  . Fixed segfault when comparing uninitialized SimpleXMLElement
+    instances. (iliaal)
+
 - Sockets:
   . Fixed various memory related issues in ext/sockets. (David Carlier)
 

ext/session/mod_mm.c

@@ -351,7 +351,7 @@ PS_READ_FUNC(mm)
 		&& ps_mm_key_exists(data, key) == FAILURE) {
 		/* key points to PS(id), but cannot change here. */
 		if (key) {
-			efree(PS(id));
+			zend_string_release_ex(PS(id), false);
 			PS(id) = NULL;
 		}
 		PS(id) = PS(mod)->s_create_sid((void **)&data);

ext/session/session.c

@@ -443,6 +443,7 @@ static zend_result php_session_initialize(void) /* {{{ */
 	if (!PS(id) || !ZSTR_VAL(PS(id))[0]) {
 		if (PS(id)) {
 			zend_string_release_ex(PS(id), 0);
+			PS(id) = NULL;
 		}
 		PS(id) = PS(mod)->s_create_sid(&PS(mod_data));
 		if (!PS(id)) {
@@ -460,6 +461,7 @@ static zend_result php_session_initialize(void) /* {{{ */
 	) {
 		if (PS(id)) {
 			zend_string_release_ex(PS(id), 0);
+			PS(id) = NULL;
 		}
 		PS(id) = PS(mod)->s_create_sid(&PS(mod_data));
 		if (!PS(id)) {
@@ -2440,6 +2442,7 @@ PHP_FUNCTION(session_regenerate_id)
 			/* Try to generate non-existing ID */
 			while (limit-- && PS(mod)->s_validate_sid(&PS(mod_data), PS(id)) == SUCCESS) {
 				zend_string_release_ex(PS(id), 0);
+				PS(id) = NULL;
 				PS(id) = PS(mod)->s_create_sid(&PS(mod_data));
 				if (!PS(id)) {
 					PS(mod)->s_close(&PS(mod_data));

ext/session/tests/user_session_module/gh23043.phpt

@@ -0,0 +1,35 @@
+--TEST--
+GH-23043 (broken session id code can cause zend_mm_heap corrupted)
+--EXTENSIONS--
+session
+--CREDITS--
+lmaltsis
+--FILE--
+<?php
+ob_start();
+class a extends SessionHandler {
+    function read($b): string {
+        return "";
+    }
+    function create_sid(): string {
+        var_dump(session_id());
+        return '';
+    }
+}
+$c = new a;
+session_set_save_handler($c);
+session_start();
+session_write_close();
+session_start();
+?>
+--EXPECTF--
+string(0) ""
+
+Warning: SessionHandler::write(): Session ID is too long or contains illegal characters. Only the A-Z, a-z, 0-9, "-", and "," characters are allowed in %s on line %d
+
+Warning: session_write_close(): Failed to write session data using user defined save handler. (session.save_path: , handler: a::write) in %s on line %d
+string(0) ""
+
+Warning: SessionHandler::write(): Session ID is too long or contains illegal characters. Only the A-Z, a-z, 0-9, "-", and "," characters are allowed in Unknown on line 0
+
+Warning: session_write_close(): Failed to write session data using user defined save handler. (session.save_path: , handler: a::write) in Unknown on line 0

ext/simplexml/simplexml.c

@@ -1229,6 +1229,12 @@ static int sxe_objects_compare(zval *object1, zval *object2) /* {{{ */
 
 	if (sxe1->node == NULL && sxe2->node == NULL) {
 		/* Both nodes not set: Only support equality comparison between documents. */
+		if (sxe1->document == NULL || sxe2->document == NULL) {
+			if (sxe1->document == sxe2->document) {
+				return 0;
+			}
+			return ZEND_UNCOMPARABLE;
+		}
 		if (sxe1->document->ptr == sxe2->document->ptr) {
 			return 0;
 		}

ext/simplexml/tests/bug_sxe_compare_uninitialized.phpt

@@ -0,0 +1,25 @@
+--TEST--
+Comparing uninitialized SimpleXMLElement instances must not segfault
+--EXTENSIONS--
+simplexml
+--FILE--
+<?php
+class MySXE extends SimpleXMLElement {
+    public function __construct() {}
+}
+$a = new MySXE;
+$b = new MySXE;
+echo "equal: ";
+var_dump($a == $b);
+echo "identical: ";
+var_dump($a === $b);
+$c = simplexml_load_string('<r/>');
+echo "uninit vs init: ";
+var_dump($a == $c);
+echo "done\n";
+?>
+--EXPECT--
+equal: bool(true)
+identical: bool(false)
+uninit vs init: bool(false)
+done

ext/standard/tests/mail/bug80751.phpt

@@ -48,7 +48,7 @@ foreach (['to' => $to, 'cc' => $cc, 'bcc' => $bcc] as $recipient => $mailAddress
         echo "Found the email. {$recipient} received.\n";
     }
 
-    if ($mail->getHeader('Return-Path') === $from) {
+    if ($mail->getHeader('Return-Path') === "<{$from}>") {
         echo "Return-Path is as expected.\n";
     }