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authorthomascube <thomas@roundcube.net>2011-11-29 10:16:42 +0000
committerthomascube <thomas@roundcube.net>2011-11-29 10:16:42 +0000
commit57486f6e58d602413b58f780bf3a94ad6d2af8ce (patch)
tree9f538706c8b5e86cce4f00e9d3b25c343210760c /program
parent6bddd9ba44e4dcb69e8d22fcaf21ec017d78e0fc (diff)
Content filter for embedded attachments to protect from XSS on IE<=8 (#1487895)
Diffstat (limited to 'program')
-rw-r--r--program/include/rcube_message.php6
-rw-r--r--program/steps/mail/func.inc4
-rw-r--r--program/steps/mail/get.inc59
-rw-r--r--program/steps/mail/show.inc2
4 files changed, 60 insertions, 11 deletions
diff --git a/program/include/rcube_message.php b/program/include/rcube_message.php
index 0ecd86c4c..633f59be2 100644
--- a/program/include/rcube_message.php
+++ b/program/include/rcube_message.php
@@ -142,10 +142,10 @@ class rcube_message
* @param string $mime_id Part MIME-ID
* @return string URL or false if part does not exist
*/
- public function get_part_url($mime_id)
+ public function get_part_url($mime_id, $embed = false)
{
if ($this->mime_parts[$mime_id])
- return $this->opt['get_url'] . '&_part=' . $mime_id;
+ return $this->opt['get_url'] . '&_part=' . $mime_id . ($embed ? '&_embed=1' : '');
else
return false;
}
@@ -511,7 +511,7 @@ class rcube_message
$img_regexp = '/^image\/(gif|jpe?g|png|tiff|bmp|svg)/';
foreach ($this->inline_parts as $inline_object) {
- $part_url = $this->get_part_url($inline_object->mime_id);
+ $part_url = $this->get_part_url($inline_object->mime_id, true);
if ($inline_object->content_id)
$a_replaces['cid:'.$inline_object->content_id] = $part_url;
if ($inline_object->content_location) {
diff --git a/program/steps/mail/func.inc b/program/steps/mail/func.inc
index b06feda7e..07a3f071d 100644
--- a/program/steps/mail/func.inc
+++ b/program/steps/mail/func.inc
@@ -551,7 +551,7 @@ function rcmail_check_safe(&$message)
* @param array CID map replaces (inline images)
* @return string Clean HTML
*/
-function rcmail_wash_html($html, $p = array(), $cid_replaces)
+function rcmail_wash_html($html, $p, $cid_replaces)
{
global $REMOTE_OBJECTS;
@@ -1068,7 +1068,7 @@ function rcmail_message_body($attrib)
) {
$out .= html::tag('hr') . html::p(array('align' => "center"),
html::img(array(
- 'src' => $MESSAGE->get_part_url($attach_prop->mime_id),
+ 'src' => $MESSAGE->get_part_url($attach_prop->mime_id, true),
'title' => $attach_prop->filename,
'alt' => $attach_prop->filename,
)));
diff --git a/program/steps/mail/get.inc b/program/steps/mail/get.inc
index a0ea3e163..721c66196 100644
--- a/program/steps/mail/get.inc
+++ b/program/steps/mail/get.inc
@@ -146,11 +146,24 @@ else if (strlen($pid = get_input_value('_part', RCUBE_INPUT_GET))) {
header("Content-Disposition: $disposition; filename=\"$filename\"");
- // turn off output buffering and print part content
- if ($part->body)
- echo $part->body;
- else if ($part->size)
- $IMAP->get_message_part($MESSAGE->uid, $part->mime_id, $part, true);
+ // do content filtering to avoid XSS through fake images
+ if (!empty($_REQUEST['_embed']) && $browser->ie && $browser->ver <= 8) {
+ if ($part->body)
+ echo preg_match('/<(script|iframe|object)/i', $part->body) ? '' : $part->body;
+ else if ($part->size) {
+ $stdout = fopen('php://output', 'w');
+ stream_filter_register('rcube_content', 'rcube_content_filter') or die('Failed to register content filter');
+ stream_filter_append($stdout, 'rcube_content');
+ $IMAP->get_message_part($MESSAGE->uid, $part->mime_id, $part, false, $stdout);
+ }
+ }
+ else {
+ // turn off output buffering and print part content
+ if ($part->body)
+ echo $part->body;
+ else if ($part->size)
+ $IMAP->get_message_part($MESSAGE->uid, $part->mime_id, $part, true);
+ }
}
exit;
@@ -178,3 +191,39 @@ header('HTTP/1.1 404 Not Found');
exit;
+
+/**
+ * PHP stream filter to detect html/javascript code in attachments
+ */
+class rcube_content_filter extends php_user_filter
+{
+ private $buffer = '';
+ private $cutoff = 2048;
+
+ function onCreate()
+ {
+ $this->cutoff = rand(2048, 3027);
+ return true;
+ }
+
+ function filter($in, $out, &$consumed, $closing)
+ {
+ while ($bucket = stream_bucket_make_writeable($in)) {
+ $this->buffer .= $bucket->data;
+
+ // check for evil content and abort
+ if (preg_match('/<(script|iframe|object)/i', $this->buffer))
+ return PSFS_ERR_FATAL;
+
+ // keep buffer small enough
+ if (strlen($this->buffer) > 4096)
+ $this->buffer = substr($this->buffer, $this->cutoff);
+
+ $consumed += $bucket->datalen;
+ stream_bucket_append($out, $bucket);
+ }
+
+ return PSFS_PASS_ON;
+ }
+}
+
diff --git a/program/steps/mail/show.inc b/program/steps/mail/show.inc
index 8976e863a..d928cfd68 100644
--- a/program/steps/mail/show.inc
+++ b/program/steps/mail/show.inc
@@ -132,7 +132,7 @@ function rcmail_message_attachments($attrib)
$ol .= html::tag('li', null,
html::a(array(
- 'href' => $MESSAGE->get_part_url($attach_prop->mime_id),
+ 'href' => $MESSAGE->get_part_url($attach_prop->mime_id, false),
'onclick' => sprintf(
'return %s.command(\'load-attachment\',{part:\'%s\', mimetype:\'%s\'},this)',
JS_OBJECT_NAME,