Don't believe the browser when detecting image artefacts

htdocs/artefact/blog/lib.php

@@ -688,6 +688,8 @@ class ArtefactTypeBlogPost extends ArtefactType {
         $tempdir = self::$blogattachmentroot . ($result->tempfilename % 256);
         $result->error = $um->process_file_upload($tempdir, $result->tempfilename);
 
+        $movedfile = get_config('dataroot') . $tempdir . '/' . $result->tempfilename;
+
         if ($result->error) {
             delete_records('artefact_blog_blogpost_file_pending', 'id', $result->tempfilename);
         }
@@ -701,8 +703,8 @@ class ArtefactTypeBlogPost extends ArtefactType {
         }
 
         db_commit();
-        safe_require('artefact', 'file');
-        $result->type = ArtefactTypeFile::detect_artefact_type($um->file['type']);
+        require_once('file.php');
+        $result->type = is_image_file($movedfile) ? 'image' : 'file';
         return $result;
     }
 

htdocs/artefact/file/lib.php

@@ -698,20 +698,18 @@ class ArtefactTypeFile extends ArtefactTypeFileBase {
         return get_config('dataroot') . self::get_file_directory($this->fileid) . '/' .  $this->fileid;
     }
 
-    public static function detect_artefact_type($mimetype) {
-        require_once('file.php');
-        if (is_image_mime_type($mimetype)) {
-            return 'image';
-        }
-        return 'file';
-    }
 
     /**
      * Test file type and return a new Image or File.
      */
     public static function new_file($path, $data) {
-        if ($data->filetype && self::detect_artefact_type($data->filetype) == 'image') {
-            list($data->width, $data->height) = getimagesize($path);
+        require_once('file.php');
+        if (is_image_file($path)) {
+            // If it's detected as an image, overwrite the browser mime type
+            $imageinfo      = getimagesize($path);
+            $data->filetype = $imageinfo['mime'];
+            $data->width    = $imageinfo[0];
+            $data->height   = $imageinfo[1];
             return new ArtefactTypeImage(0, $data);
         }
         return new ArtefactTypeFile(0, $data);
@@ -1246,14 +1244,6 @@ class ArtefactTypeImage extends ArtefactTypeFile {
         return 'file';
    } 
 
-    /**
-     * err... wtf. Let's find where this method is called and change the call eh?
-     */
-    public static function is_image_mime_type($type) {
-        require_once('file.php');
-        return is_image_mime_type($type);
-    }
-
     public static function get_icon($options=null) {
         $url = get_config('wwwroot') . 'artefact/file/download.php?';
         $url .= 'file=' . $options['id'];

htdocs/artefact/file/profileicons.php

@@ -165,7 +165,8 @@ $filesize = 0;
 function upload_validate(Pieform $form, $values) {
     global $USER, $filesize;
     require_once('file.php');
-    if (!is_image_mime_type($values['file']['type'])) {
+    $imageinfo = getimagesize($values['file']['tmp_name']);
+    if (!$imageinfo || !is_image_type($imageinfo[2])) {
         $form->set_error('file', get_string('filenotimage'));
     }
 
@@ -179,7 +180,8 @@ function upload_validate(Pieform $form, $values) {
     }
 
     // Check the file isn't greater than the max allowable size
-    list($width, $height) = getimagesize($values['file']['tmp_name']);
+    $width          = $imageinfo[0];
+    $height         = $imageinfo[1];
     $imagemaxwidth  = get_config('imagemaxwidth');
     $imagemaxheight = get_config('imagemaxheight');
     if ($width > $imagemaxwidth || $height > $imagemaxheight) {
@@ -211,10 +213,12 @@ function upload_submit(Pieform $form, $values) {
         'owner'    => $USER->id,
         'title'    => $values['title'] ? $values['title'] : $values['file']['name'],
         'note'     => $values['file']['name'],
-        'filetype' => $values['file']['type'],
         'size'     => $filesize,
     );
-    list($data->width, $data->height) = getimagesize($values['file']['tmp_name']);
+    $imageinfo = getimagesize($values['file']['tmp_name']);
+    $data->width    = $imageinfo[0];
+    $data->height   = $imageinfo[1];
+    $data->filetype = $imageinfo['mime'];
     $artefact = new ArtefactTypeProfileIcon(0, $data);
     if (preg_match("/\.([^\.]+)$/", $values['file']['name'], $saved)) {
         $artefact->set('oldextension', $saved[1]);

htdocs/auth/xmlrpc/lib.php

@@ -301,12 +301,12 @@ class AuthXmlrpc extends Auth {
 
                     require_once('file.php');
                     $imagesize = getimagesize($filename);
-                    $mime = $imagesize['mime'];
-                    if (!is_image_mime_type($mime)) {
+                    if (!$imagesize || !is_image_type($imagesize[2])) {
                         $error = get_string('filenotimage');
                     }
 
-                    $width = $imagesize[0];
+                    $mime   = $imagesize['mime'];
+                    $width  = $imagesize[0];
                     $height = $imagesize[1];
                     $imagemaxwidth  = get_config('imagemaxwidth');
                     $imagemaxheight = get_config('imagemaxheight');

htdocs/lib/file.php

@@ -328,6 +328,43 @@ function is_image_mime_type($type) {
     return in_array($type, $supported);
 }
 
+
+/**
+ * Given an image type returned by getimagesize or exif_imagetype, returns whether
+ * Mahara thinks it is a valid image type.
+ *
+ * Not all image types are valid for Mahara. Mahara supports JPEG, PNG, GIF
+ * and BMP.
+ *
+ * @param string $type The type to check
+ * @return boolean     Whether the type is a valid image type for Mahara
+ */
+function is_image_type($type) {
+    $supported = array(IMAGETYPE_GIF, IMAGETYPE_JPEG, IMAGETYPE_PNG);
+    if (extension_loaded('imagick')) {
+        $supported[] = IMAGETYPE_BMP;
+    }
+    return $type && in_array($type, $supported);
+}
+
+
+/**
+ * Given path to a file, returns whether Mahara thinks it is a valid image file.
+ *
+ * Not all image types are valid for Mahara. Mahara supports JPEG, PNG, GIF
+ * and BMP.
+ *
+ * @param string $path The file to check
+ * @return boolean     Whether the file is a valid image file for Mahara
+ */
+function is_image_file($path) {
+    if (!$type = exif_imagetype($path)) {
+        return false;
+    }
+    return is_image_type($type);
+}
+
+
 /**
  * Given a path under dataroot, an ID and a size, return the path to a file
  * matching all criteria.