Fix #66322: COMPersistHelper::SaveToFile can save to wrong location

Saving under the given `filename` may also work, but since
`::LoadFromFile` uses the `fullpath` we follow suit.

Author: cmb69

NEWS

@@ -2,6 +2,10 @@ PHP                                                                        NEWS
 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 ?? ??? ????, PHP 7.3.16
 
+- COM:
+  . Fixed bug #66322 (COMPersistHelper::SaveToFile can save to wrong location).
+    (cmb)
+
 - PCRE:
   . Fixed bug #79188 (Memory corruption in preg_replace/preg_replace_callback
     and unicode). (Nikita)

ext/com_dotnet/com_persist.c

@@ -398,7 +398,7 @@ CPH_METHOD(SaveToFile)
 				RETURN_FALSE;
 			}
 
-			olefilename = php_com_string_to_olestring(filename, strlen(fullpath), helper->codepage);
+			olefilename = php_com_string_to_olestring(fullpath, strlen(fullpath), helper->codepage);
 			efree(fullpath);
 		}
 		res = IPersistFile_Save(helper->ipf, olefilename, remember);

ext/com_dotnet/tests/bug66322.phpt

@@ -0,0 +1,24 @@
+--TEST--
+Bug #66322 (COMPersistHelper::SaveToFile can save to wrong location)
+--SKIPIF--
+<?php
+if (!extension_loaded('com_dotnet')) die('skip com_dotnet extension not available');
+try {
+    new COM('Word.Application');
+} catch (com_exception $ex) {
+    die('skip MS Word not available');
+}
+if (getenv("SKIP_SLOW_TESTS")) die('skip slow test');
+?>
+--FILE--
+<?php
+$w = new COM('Word.Application');
+$doc = $w->Documents->Add();
+$ph = new COMPersistHelper($doc);
+$filename = __DIR__ . '\\..\\' . basename(__DIR__) . '\\66322.docx';
+$ph->SaveToFile($filename);
+var_dump(file_exists($filename));
+$w->Quit();
+?>
+--EXPECT--
+bool(true)