Fix bug #53226 (file_exists fails on big filenames).

main/fopen_wrappers.c

@@ -291,6 +291,14 @@ PHPAPI int php_check_open_basedir_ex(const char *path, int warn TSRMLS_DC)
 		char *ptr;
 		char *end;
 
+		/* Check if the path is too long so we can give a more useful error
+		* message. */
+		if (strlen(path) > (MAXPATHLEN - 1)) {
+			php_error_docref(NULL TSRMLS_CC, E_WARNING, "File name is longer than the maximum allowed path length on this platform (%d): %s", MAXPATHLEN, path);
+			errno = EINVAL;
+			return -1;
+		}
+
 		pathbuf = estrdup(PG(open_basedir));
 
 		ptr = pathbuf;

tests/security/bug53226.phpt

@@ -0,0 +1,31 @@
+--TEST--
+Bug #53226 (file_exists fails on big filenames)
+--INI--
+open_basedir=.
+--FILE--
+<?php
+require_once "open_basedir.inc";
+create_directories();
+
+var_dump(file_exists('./test/ok/ok.txt'));
+var_dump(file_exists('./test/foo'));
+
+// Picked an arbitrarily large number that should be beyond PATH_MAX on every
+// OS I know about.
+$file = str_repeat('x', 40000);
+var_dump(file_exists("./test/$file"));
+?>
+--CLEAN--
+<?php
+require_once "open_basedir.inc";
+delete_directories();
+?>
+--EXPECTF--
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(false)
+
+Warning: file_exists(): File name is longer than the maximum allowed path length on this platform (%d): %s in %s on line %d
+bool(false)