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Add static function to propose security settings

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Close #3, see #4
This commit is contained in:
Joshua Ramon Enslin 2020-11-12 00:12:11 +01:00 committed by Stefan Rohde-Enslin
parent ae39bdf741
commit 5130477e4b
Signed by: jrenslin
GPG Key ID: 46016F84501B70AE
1 changed files with 89 additions and 2 deletions
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91
MD_JAIL.php
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@ -38,6 +38,93 @@ final class MD_JAIL {
*/
public string $memory_limit;
/**
* Static function providing an advisory on how to harden the php.ini or
* .user.ini.
*
* @param array{shell_access_whitelist: string[], sys_function_whitelist: string[], file_function_whitelist: string[], file_uploads: bool, allow_url_fopen: bool, max_input_vars: integer, max_input_nesting_level: integer, curl: bool} $requested_resources Requested resources.
*
* @return string
*/
public static function check_server_setup(array $requested_resources):string {
# ini_set("open_basedir", __DIR__ . "/../../");
$disable_functions = [
"dl", # Loads a PHP extension at runtime
"opcache_get_status", # Gets opcache status
"phpinfo", # For obvious reasons
"parse_ini_file", # For obvious reasons
"show_source", "highlight_file", # Aliases; serve the content of a PHP file
"php_uname", # Returns information about the operating system PHP is running on
"phpcredits", # Credits page of PHP authors
"php_strip_whitespace", # Return PHP source with stripped comments and whitespace
"popen", "pclose", # Similar to fopen, but capable of shell access
"virtual", # Perform an Apache sub-request
];
$disable_aliases = [
"ini_set" => "ini_alter", # Alias of ini_set(), ini_set is preferred
"disk_free_space" => "diskfreespace", # Alias of disk_free_space()
"PHP_SAPI" => "php_sapi_name", # Alias of constant PHP_SAPI
"stream_set_write_buffer" => "set_file_buffer", # Alias of stream_set_write_buffer()
];
$shell_access_functions = array_diff(["exec", "passthru", "proc_close", "proc_get_status", "proc_nice", "proc_open", "proc_terminate", "shell_exec", "system"], $requested_resources['shell_access_whitelist']);
$sys_functions = array_diff(["get_current_user", "getmyuid", "getmygid", "getmypid", "getmyinode", "getlastmod", "getenv", "putenv"], $requested_resources['sys_function_whitelist']);
$file_functions = array_diff(["chgrp", "chgrp", "lchgrp", "lchown", "link", "linkinfo", "symlink"], $requested_resources['file_function_whitelist']);
if ($requested_resources['curl'] === false) {
$disable_functions[] = "curl_init";
$disable_functions[] = "curl_exec";
$disable_functions[] = "curl_multi_init";
$disable_functions[] = "curl_multi_exec";
}
$disabledWOAliases = array_merge($disable_functions, $shell_access_functions, $sys_functions, $file_functions);
$output = '## php.ini' . PHP_EOL . PHP_EOL;
$output .= PHP_EOL . "php_value[disable_functions] = \"" . implode(", ", array_merge($disabledWOAliases, $disable_aliases)) . "\"";
if ($requested_resources['file_uploads'] === false) {
$output .= PHP_EOL . "php_value[file_uploads] = 0";
}
if ($requested_resources['allow_url_fopen'] === false) {
$output .= PHP_EOL . "php_value[allow_url_fopen] = 0";
}
$output .= PHP_EOL . PHP_EOL . '## .user.ini' . PHP_EOL;
if ($requested_resources['file_uploads'] === false) {
$output .= PHP_EOL . "php_value[upload_max_filesize] = 1";
}
if ($requested_resources['max_input_vars'] != ini_get("max_input_vars")) {
$output .= PHP_EOL . "php_value[max_input_vars] = " . $requested_resources['max_input_vars'];
}
if ($requested_resources['max_input_nesting_level'] != ini_get("max_input_nesting_level")) {
$output .= PHP_EOL . "php_value[max_input_nesting_level] = " . $requested_resources['max_input_nesting_level'];
}
$output .= PHP_EOL . PHP_EOL . '## PHPStan Directives' . PHP_EOL . PHP_EOL . " disallowedFunctionCalls:" . PHP_EOL;
foreach ($disable_aliases as $to_keep => $disabled) {
$output .= '
-
function: \'' . $disabled . '()\'
message: \'use ' . $to_keep . ' instead\'';
}
foreach ($disabledWOAliases as $disabled) {
$output .= '
- function: \'' . $disabled . '()\'';
}
return $output;
}
/**
* Registers an additional accessible directory for open_basedir.
*
@ -87,6 +174,7 @@ final class MD_JAIL {
* Applies basedir restrictions.
*
* @return void
*/
private function _apply_basedir_restriction():void {
if (empty($this->_open_basedir)) {
@ -97,7 +185,6 @@ final class MD_JAIL {
}
}
*/
/**
* Enforces security options previously set.
@ -124,7 +211,7 @@ final class MD_JAIL {
$this->_apply_time_limit();
// Set accessible file paths
// $this->_apply_basedir_restriction();
$this->_apply_basedir_restriction();
$this->_status = self::STATUS_SPECIFIED;
$this->__destruct();