External libraries: Improve attachment handling in PHPMailer

Props: audrasjb, ayeshrajans, desrosj, peterwilsoncc, xknown.
Partially merges [50799] to the 4.6 branch.


Built from https://develop.svn.wordpress.org/branches/4.6@50858


git-svn-id: http://core.svn.wordpress.org/branches/4.6@50467 1a063a9b-81f0-0310-95a4-ce76da25c4cd
This commit is contained in:
Peter Wilson 2021-05-12 22:33:35 +00:00
parent 2a920d0912
commit 155c2ad271
1 changed files with 46 additions and 8 deletions

View File

@ -1294,9 +1294,12 @@ class PHPMailer
// Sign with DKIM if enabled
if (!empty($this->DKIM_domain)
&& !empty($this->DKIM_selector)
&& (!empty($this->DKIM_private_string)
|| (!empty($this->DKIM_private) && file_exists($this->DKIM_private))
and !empty($this->DKIM_selector)
and (!empty($this->DKIM_private_string)
or (!empty($this->DKIM_private)
and self::isPermittedPath($this->DKIM_private)
and file_exists($this->DKIM_private)
)
)
) {
$header_dkim = $this->DKIM_Add(
@ -1461,6 +1464,39 @@ class PHPMailer
return true;
}
/**
* Check whether a file path is of a permitted type.
* Used to reject URLs and phar files from functions that access local file paths,
* such as addAttachment.
* @param string $path A relative or absolute path to a file.
* @return bool
*/
protected static function isPermittedPath($path)
{
//Matches scheme definition from https://tools.ietf.org/html/rfc3986#section-3.1
return !preg_match('#^[a-z][a-z\d+.-]*://#i', $path);
}
/**
* Check whether a file path is safe, accessible, and readable.
*
* @param string $path A relative or absolute path to a file
*
* @return bool
*/
protected static function fileIsAccessible($path)
{
if (!self::isPermittedPath($path)) {
return false;
}
$readable = file_exists($path);
//If not a UNC path (expected to start with \\), check read permission, see #2069
if (strpos($path, '\\\\') !== 0) {
$readable = $readable && is_readable($path);
}
return $readable;
}
/**
* Send mail using the PHP mail() function.
* @param string $header The message headers
@ -1784,7 +1820,7 @@ class PHPMailer
// There is no English translation file
if ($langcode != 'en') {
// Make sure language file path is readable
if (!is_readable($lang_file)) {
if (!self::fileIsAccessible($lang_file)) {
$foundlang = false;
} else {
// Overwrite language-specific strings.
@ -2495,6 +2531,8 @@ class PHPMailer
* Add an attachment from a path on the filesystem.
* Never use a user-supplied path to a file!
* Returns false if the file could not be found or read.
* Explicitly *does not* support passing URLs; PHPMailer is not an HTTP client.
* If you need to do that, fetch the resource yourself and pass it in via a local file or string.
* @param string $path Path to the attachment.
* @param string $name Overrides the attachment name.
* @param string $encoding File encoding (see $Encoding).
@ -2506,7 +2544,7 @@ class PHPMailer
public function addAttachment($path, $name = '', $encoding = 'base64', $type = '', $disposition = 'attachment')
{
try {
if (!@is_file($path)) {
if (!self::fileIsAccessible($path)) {
throw new phpmailerException($this->lang('file_access') . $path, self::STOP_CONTINUE);
}
@ -2687,7 +2725,7 @@ class PHPMailer
protected function encodeFile($path, $encoding = 'base64')
{
try {
if (!is_readable($path)) {
if (!self::fileIsAccessible($path)) {
throw new phpmailerException($this->lang('file_open') . $path, self::STOP_CONTINUE);
}
$magic_quotes = get_magic_quotes_runtime();
@ -3031,7 +3069,7 @@ class PHPMailer
*/
public function addEmbeddedImage($path, $cid, $name = '', $encoding = 'base64', $type = '', $disposition = 'inline')
{
if (!@is_file($path)) {
if (!self::fileIsAccessible($path)) {
$this->setError($this->lang('file_access') . $path);
return false;
}