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SRI + XHTML #5742

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SRI + XHTML #5742

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7c61f95
SRI + XHTML
corrideat Apr 29, 2017
81ceca0
Update rcmail_output_html.php
corrideat Jun 4, 2017
4268161
Check whether sha384 exists
corrideat Jun 4, 2017
d80cdd4
Added description of SRI to defaults.inc.php
corrideat Jun 4, 2017
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64 changes: 60 additions & 4 deletions program/include/rcmail_output_html.php
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Original file line number Diff line number Diff line change
Expand Up @@ -46,6 +46,7 @@ class rcmail_output_html extends rcmail_output
protected $body = '';
protected $base_path = '';
protected $assets_path;
protected $assets_sri = false;
protected $assets_dir = RCUBE_INSTALL_PATH;
protected $devel_mode = false;

Expand Down Expand Up @@ -84,6 +85,7 @@ public function __construct($task = null, $framed = false)
$this->set_env('skin', $skin);

$this->set_assets_path($this->config->get('assets_path'), $this->config->get('assets_dir'));
$this->assets_sri = $this->config->get('assets_sri');

if (!empty($_REQUEST['_extwin']))
$this->set_env('extwin', 1);
Expand Down Expand Up @@ -755,6 +757,29 @@ public function raise_error($code, $message)
exit;
}

/**
* Get the sha384 hash for local assets
*/
public function asset_sri($path)
{
// iframe content can't be in a different domain
// @TODO: check if assests are on a different domain

if (!$this->assets_sri || in_array($path[0], array('?', '/', '.')) || strpos($path, '://')) {
return false;
}

list($file) = explode('?', $path, 2);
if (!empty($file) && is_readable($file)) {
$content = @file_get_contents($this->assets_dir . $file);
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Here you use assets_dir, but one line above you don't.

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Fair point. I missed that.

if ($content !== false) {
return 'sha384-'.base64_encode(hash('sha384', $content, true));
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Would be good to check if 'hash' function exists, e.g. when you set $this->assets_sri.

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Fair point.

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I propose to use hash_file() instead of hash() and file_get_contents().

}
}

return false;
}

/**
* Modify path by adding URL prefix if configured
*/
Expand Down Expand Up @@ -802,7 +827,7 @@ protected function globals_callback($matches)
protected function fix_paths($output)
{
return preg_replace_callback(
'!(src|href|background)=(["\']?)([a-z0-9/_.-]+)(["\'\s>])!i',
'!(src|href|background)=(["\']?)([a-z0-9/_.-]+)\2([\s>]?)!i',
array($this, 'file_callback'), $output);
}

Expand All @@ -826,7 +851,34 @@ protected function file_callback($matches)
$file = $this->file_mod($file);
}

return $matches[1] . '=' . $matches[2] . $file . $matches[4];
return $matches[1] . '=' . $matches[2] . $file . $matches[2] . $matches[4];
}

/**
* Add SRI tags to assets
*/
protected function include_assets_sri($output)
{
return preg_replace_callback(
'!(src|href|background)=(["\']?)([a-z0-9/_.?=-]+)\2([\s>])?!i',
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W3C specification talks only about link and script tags. Do we really want to handle all others, e.g. img?

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I went this route because it was easier to implement for everything and because future browsers may support SRI in other tags. I concur that for performance reasons this might not be the best approach.

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A slightly off-topic comment: the current way of implementing these features using templates (i.e., generate a document, then use regexes) seems error-prone and inefficient. I think a DOM-based (or similar) document generation approach could be more reliable and flexible (even though it's hard to say what the effect on performance may be.) Have you considered changing this?

array($this, 'sri_callback'), $output);
}

/**
* Callback function for preg_replace_callback in include_assets_sri()
*
* @return string Parsed string
*/
protected function sri_callback($matches)
{
$attrs = '';
$sri = $this->asset_sri($matches[3]);

if (!empty($sri)) {
$attrs = ' integrity="' . $sri . '" crossorigin="anonymous"';
}

return $matches[1] . '=' . $matches[2] . $matches[3] . $matches[2] . $attrs . $matches[4];
}

/**
Expand All @@ -835,7 +887,7 @@ protected function file_callback($matches)
protected function fix_assets_paths($output)
{
return preg_replace_callback(
'!(src|href|background)=(["\']?)([a-z0-9/_.?=-]+)(["\'\s>])!i',
'!(src|href|background)=(["\']?)([a-z0-9/_.?=-]+)\2([\s>])?!i',
array($this, 'assets_callback'), $output);
}

Expand All @@ -848,7 +900,7 @@ protected function assets_callback($matches)
{
$file = $this->asset_url($matches[3]);

return $matches[1] . '=' . $matches[2] . $file . $matches[4];
return $matches[1] . '=' . $matches[2] . $file . $matches[2] . $matches[4];
}

/**
Expand Down Expand Up @@ -1679,6 +1731,10 @@ protected function _write($templ = '', $base_path = '')

$output = $this->parse_with_globals($this->fix_paths($output));

if ($this->assets_sri) {
$output = $this->include_assets_sri($output);
}

if ($this->assets_path) {
$output = $this->fix_assets_paths($output);
}
Expand Down
3 changes: 2 additions & 1 deletion program/lib/Roundcube/html.php
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Original file line number Diff line number Diff line change
Expand Up @@ -86,7 +86,7 @@ public static function tag($tagname, $attrib = array(), $content = null, $allowe
return '<' . $tagname . self::attrib_string($attrib, $allowed) . '>' . $content . $suffix;
}
else {
return '<' . $tagname . self::attrib_string($attrib, $allowed) . '>' . $suffix;
return '<' . $tagname . self::attrib_string($attrib, $allowed) . '/>' . $suffix;
}
}

Expand All @@ -99,6 +99,7 @@ public static function doctype($type)
{
$doctypes = array(
'html5' => '<!DOCTYPE html>',
'xhtml-html5' => '<!DOCTYPE html>',
'xhtml' => '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">',
'xhtml-trans' => '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">',
'xhtml-strict' => '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">',
Expand Down