3 This is an upload script for SWFUpload that attempts to properly handle uploaded files
8 SWFUpload doesn't send a MIME-TYPE. In my opinion this is ok since MIME-TYPE is no better than
9 file extension and is probably worse because it can vary from OS to OS and browser to browser (for the same file).
10 The best thing to do is content sniff the file but this can be resource intensive, is difficult, and can still be fooled or inaccurate.
11 Accepting uploads can never be 100% secure.
13 You can't guarantee that SWFUpload is really the source of the upload. A malicious user
14 will probably be uploading from a tool that sends invalid or false metadata about the file.
15 The script should properly handle this.
17 The script should not over-write existing files.
19 The script should strip away invalid characters from the file name or reject the file.
21 The script should not allow files to be saved that could then be executed on the webserver (such as .php files).
22 To keep things simple we will use an extension whitelist for allowed file extensions. Which files should be allowed
23 depends on your server configuration. The extension white-list is _not_ tied your SWFUpload file_types setting
25 For better security uploaded files should be stored outside the webserver's document root. Downloaded files
26 should be accessed via a download script that proxies from the file system to the webserver. This prevents
27 users from executing malicious uploaded files. It also gives the developer control over the outgoing mime-type,
28 access restrictions, etc. This, however, is outside the scope of this script.
30 SWFUpload sends each file as a separate POST rather than several files in a single post. This is a better
31 method in my opinions since it better handles file size limits, e.g., if post_max_size is 100 MB and I post two 60 MB files then
32 the post would fail (2x60MB = 120MB). In SWFupload each 60 MB is posted as separate post and we stay within the limits. This
33 also simplifies the upload script since we only have to handle a single file.
35 The script should properly handle situations where the post was too large or the posted file is larger than
36 our defined max. These values are not tied to your SWFUpload file_size_limit setting.
40 define('AT_INCLUDE_PATH', '../');
41 require(AT_INCLUDE_PATH.'vitals.inc.php');
43 if (!authenticate(AT_PRIV_FILES,AT_PRIV_RETURN)) {
44 authenticate(AT_PRIV_CONTENT);
48 // Code for Session Cookie workaround
50 if (isset($_POST["PHPSESSID"])) {
51 session_id($_POST["PHPSESSID"]);
52 } else if (isset($_GET["PHPSESSID"])) {
53 session_id($_GET["PHPSESSID"]);
59 // Check post_max_size (http://us3.php.net/manual/en/features.file-upload.php#73762)
60 $POST_MAX_SIZE = ini_get('post_max_size');
61 $unit = strtoupper(substr($POST_MAX_SIZE, -1));
62 $multiplier = ($unit == 'M' ? 1048576 : ($unit == 'K' ? 1024 : ($unit == 'G' ? 1073741824 : 1)));
64 if ((int)$_SERVER['CONTENT_LENGTH'] > $multiplier*(int)$POST_MAX_SIZE && $POST_MAX_SIZE) {
65 header("HTTP/1.1 500 Internal Server Error");
66 echo "POST exceeded maximum allowed size.";
71 // $save_path = "/home/elicochr/public_html/sos/uploads/";
72 $save_path = urldecode($_GET['path']);
73 $content_path = AT_CONTENT_DIR . $_SESSION['course_id'];
74 $pos = strpos(realpath($save_path), $content_path);
76 HandleError("Error uploading a file.");
79 $upload_name = "Filedata";
80 $max_file_size_in_bytes = 2147483647; // 2GB in bytes
81 //$extension_whitelist = array("jpg", "gif", "png"); // Allowed file extensions
82 $valid_chars_regex = '.A-Z0-9_ !@#$%^&()+={}\[\]\',~`-'; // Characters allowed in the file name (in a Regular Expression format)
85 $MAX_FILENAME_LENGTH = 260;
88 $uploadErrors = array(
89 0=>"There is no error, the file uploaded with success",
90 1=>"The uploaded file exceeds the upload_max_filesize directive in php.ini",
91 2=>"The uploaded file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form",
92 3=>"The uploaded file was only partially uploaded",
93 4=>"No file was uploaded",
94 6=>"Missing a temporary folder"
98 // Validate the upload
99 if (!isset($_FILES[$upload_name])) {
100 HandleError("No upload found in \$_FILES for " . $upload_name);
102 } else if (isset($_FILES[$upload_name]["error"]) && $_FILES[$upload_name]["error"] != 0) {
103 HandleError($uploadErrors[$_FILES[$upload_name]["error"]]);
105 } else if (!isset($_FILES[$upload_name]["tmp_name"]) || !@is_uploaded_file($_FILES[$upload_name]["tmp_name"])) {
106 HandleError("Upload failed is_uploaded_file test.");
108 } else if (!isset($_FILES[$upload_name]['name'])) {
109 HandleError("File has no name.");
113 // Validate the file size (Warning: the largest files supported by this code is 2GB)
114 $file_size = @filesize($_FILES[$upload_name]["tmp_name"]);
115 if (!$file_size || $file_size > $max_file_size_in_bytes) {
116 HandleError("File exceeds the maximum allowed size");
120 if ($file_size <= 0) {
121 HandleError("File size outside allowed lower bound");
126 // Validate file name (for our purposes we'll just remove invalid characters)
127 $file_name = preg_replace('/[^'.$valid_chars_regex.']|\.+$/i', "", basename($_FILES[$upload_name]['name']));
128 if (strlen($file_name) == 0 || strlen($file_name) > $MAX_FILENAME_LENGTH) {
129 HandleError("Invalid file name");
133 // Validate that we won't over-write an existing file
134 if (file_exists($save_path . $file_name)) {
135 HandleError("File with this name already exists");
139 // Validate file extension
140 $path_parts = pathinfo($_FILES[$upload_name]['name']);
141 $ext = $path_parts['extension'];
143 /* check if this file extension is allowed: */
144 /* $IllegalExtentions is defined in ./include/config.inc.php */
145 if (in_array($ext, $IllegalExtentions)) {
146 HandleError("Invalid file extension");
151 // Validate file contents (extension and mime-type can't be trusted)
153 Validating the file contents is OS and web server configuration dependant. Also, it may not be reliable.
154 See the comments on this page: http://us2.php.net/fileinfo
156 Also see http://72.14.253.104/search?q=cache:3YGZfcnKDrYJ:www.scanit.be/uploads/php-file-upload.pdf+php+file+command&hl=en&ct=clnk&cd=8&gl=us&client=firefox-a
157 which describes how a PHP script can be embedded within a GIF image file.
159 Therefore, no sample code will be provided here. Research the issue, decide how much security is
160 needed, and implement a solution that meets the needs.
166 At this point we are ready to process the valid file. This sample code shows how to save the file. Other tasks
167 could be done such as creating an entry in a database or generating a thumbnail.
169 Depending on your server OS and needs you may need to set the Security Permissions on the file after it has
172 if (!@move_uploaded_file($_FILES[$upload_name]["tmp_name"], $save_path.$file_name)) {
173 HandleError("File could not be saved.");
177 // Return output to the browser (only supported by SWFUpload for Flash Player 9)
179 echo "File Received";
183 /* Handles the error output. This function was written for SWFUpload for Flash Player 8 which
184 cannot return data to the server, so it just returns a 500 error. For Flash Player 9 you will
185 want to change this to return the server data you want to indicate an error and then use SWFUpload's
186 uploadSuccess to check the server_data for your error indicator. */
187 function HandleError($message) {
188 header("HTTP/1.1 500 Internal Server Error");