Fix bug #76857: Can read "non-existant" files

This change makes checked and opened file consistent in a way that it is
using real path for stat operation in the same way like it is used for
open.

Closes GH-12067

NEWS

@@ -23,6 +23,7 @@ PHP                                                                        NEWS
 - Streams:
   . Fixed bug #52335 (fseek() on memory stream behavior different than file).
     (Jakub Zelenka)
+  . Fixed bug #76857 (Can read "non-existant" files). (Jakub Zelenka)
 
 17 Aug 2023, PHP 8.3.0beta3
 

UPGRADING

@@ -651,6 +651,9 @@ PHP 8.3 UPGRADE NOTES
   . Memory stream no longer fails if seek offset is past the end. Instead
     the memory is increase on the next write and date between the old end and
     offset is filled with zero bytes in the same way how it works for files.
+  . stat() access operartions like file_exists() and similar will now use real
+    path instead of the actual stream path. This is consitent with stream
+    opening.
 
 ========================================
 14. Performance Improvements

ext/standard/filestat.c

@@ -726,26 +726,29 @@ PHPAPI void php_stat(zend_string *filename, int type, zval *return_value)
 		}
 
 		if (wrapper == &php_plain_files_wrapper) {
-
+			char realpath[MAXPATHLEN];
+			if (expand_filepath(local, realpath) == NULL) {
+				strlcpy(realpath, local, sizeof(realpath));
+			}
 			switch (type) {
 #ifdef F_OK
 				case FS_EXISTS:
-					RETURN_BOOL(VCWD_ACCESS(local, F_OK) == 0);
+					RETURN_BOOL(VCWD_ACCESS(realpath, F_OK) == 0);
 					break;
 #endif
 #ifdef W_OK
 				case FS_IS_W:
-					RETURN_BOOL(VCWD_ACCESS(local, W_OK) == 0);
+					RETURN_BOOL(VCWD_ACCESS(realpath, W_OK) == 0);
 					break;
 #endif
 #ifdef R_OK
 				case FS_IS_R:
-					RETURN_BOOL(VCWD_ACCESS(local, R_OK) == 0);
+					RETURN_BOOL(VCWD_ACCESS(realpath, R_OK) == 0);
 					break;
 #endif
 #ifdef X_OK
 				case FS_IS_X:
-					RETURN_BOOL(VCWD_ACCESS(local, X_OK) == 0);
+					RETURN_BOOL(VCWD_ACCESS(realpath, X_OK) == 0);
 					break;
 #endif
 			}

ext/standard/tests/streams/bug76857.phpt

@@ -0,0 +1,20 @@
+--TEST--
+Bug #76857 (Can read "non-existant" files)
+--FILE--
+<?php
+file_put_contents(__DIR__ . '/bug76857_data.txt', 'test data');
+$path = "foobar://google.com/../../bug76857_data.txt";
+chdir(__DIR__);
+var_dump(file_exists($path));
+var_dump(file_get_contents($path, false, null, 0, 10));
+?>
+--EXPECTF--
+Warning: file_exists(): Unable to find the wrapper "foobar" - did you forget to enable it when you configured PHP? in %s on line %d
+bool(true)
+
+Warning: file_get_contents(): Unable to find the wrapper "foobar" - did you forget to enable it when you configured PHP? in %s on line %d
+string(9) "test data"
+--CLEAN--
+<?php
+@unlink(__DIR__ . '/bug76857_data.txt');
+?>