mitigate path traversal vulnerability by validating folder and file inputs

This commit is contained in:
Ryan
2025-04-04 18:02:21 -04:00
committed by GitHub
parent f19d30f58a
commit da62e70c02

View File

@@ -1,8 +1,6 @@
<?php
require_once 'config.php';
// For GET requests (which download.php will use), we assume session authentication is enough.
// Check if the user is authenticated.
if (!isset($_SESSION['authenticated']) || $_SESSION['authenticated'] !== true) {
http_response_code(401);
@@ -22,38 +20,70 @@ if (!preg_match('/^[A-Za-z0-9_\-\.\(\) ]+$/', $file)) {
exit;
}
// Determine the directory.
if ($folder !== 'root') {
$directory = rtrim(UPLOAD_DIR, '/\\') . DIRECTORY_SEPARATOR . $folder . DIRECTORY_SEPARATOR;
} else {
$directory = UPLOAD_DIR;
// Get the realpath of the upload directory.
$uploadDirReal = realpath(UPLOAD_DIR);
if ($uploadDirReal === false) {
http_response_code(500);
echo json_encode(["error" => "Server misconfiguration."]);
exit;
}
$filePath = $directory . $file;
// Determine the directory.
if ($folder === 'root') {
$directory = $uploadDirReal;
} else {
// Prevent path traversal in folder parameter.
if (strpos($folder, '..') !== false) {
http_response_code(400);
echo json_encode(["error" => "Invalid folder name."]);
exit;
}
$directoryPath = rtrim(UPLOAD_DIR, '/\\') . DIRECTORY_SEPARATOR . $folder;
$directory = realpath($directoryPath);
// Ensure that the resolved directory exists and is within the allowed UPLOAD_DIR.
if ($directory === false || strpos($directory, $uploadDirReal) !== 0) {
http_response_code(400);
echo json_encode(["error" => "Invalid folder path."]);
exit;
}
}
if (!file_exists($filePath)) {
// Build the file path.
$filePath = $directory . DIRECTORY_SEPARATOR . $file;
$realFilePath = realpath($filePath);
// Validate that the real file path exists and is within the allowed directory.
if ($realFilePath === false || strpos($realFilePath, $uploadDirReal) !== 0) {
http_response_code(403);
echo json_encode(["error" => "Access forbidden."]);
exit;
}
if (!file_exists($realFilePath)) {
http_response_code(404);
echo json_encode(["error" => "File not found."]);
exit;
}
// Serve the file.
$mimeType = mime_content_type($filePath);
$mimeType = mime_content_type($realFilePath);
header("Content-Type: " . $mimeType);
// For images, serve inline; for other types, force download.
$ext = strtolower(pathinfo($filePath, PATHINFO_EXTENSION));
$ext = strtolower(pathinfo($realFilePath, PATHINFO_EXTENSION));
if (in_array($ext, ['jpg','jpeg','png','gif','bmp','webp','svg','ico'])) {
header('Content-Disposition: inline; filename="' . basename($filePath) . '"');
header('Content-Disposition: inline; filename="' . basename($realFilePath) . '"');
} else {
header('Content-Disposition: attachment; filename="' . basename($filePath) . '"');
header('Content-Disposition: attachment; filename="' . basename($realFilePath) . '"');
}
header('Content-Length: ' . filesize($filePath));
header('Content-Length: ' . filesize($realFilePath));
// Disable caching.
header('Cache-Control: no-store, no-cache, must-revalidate');
header('Pragma: no-cache');
readfile($filePath);
readfile($realFilePath);
exit;
?>