Add API module to receive CSP reports.
authorBrian Wolff <bawolff+wn@gmail.com>
Mon, 29 Feb 2016 03:57:10 +0000 (22:57 -0500)
committerBrian Wolff <bawolff+wn@gmail.com>
Tue, 28 Jun 2016 19:37:27 +0000 (15:37 -0400)
There are two expected usecases for this:
* The proposed builtin CSP support at I80f6f4
* Setting CSP headers on media served from upload.wikimedia.org

This was split from I80f6f46

For details on CSP, see http://www.w3.org/TR/CSP2/
See also https://www.mediawiki.org/wiki/Requests_for_comment/Content-Security-Policy

Related to (but not directly a fix for) T117618

Bug: T135963
Change-Id: Id92126ca7707186757e77fe50cd336ff1acb8b3f

autoload.php
includes/api/ApiCSPReport.php [new file with mode: 0644]
includes/api/ApiMain.php
includes/api/i18n/en.json
includes/api/i18n/qqq.json

index 87ba225..c02ae62 100644 (file)
@@ -28,6 +28,7 @@ $wgAutoloadLocalClasses = [
        'ApiComparePages' => __DIR__ . '/includes/api/ApiComparePages.php',
        'ApiContinuationManager' => __DIR__ . '/includes/api/ApiContinuationManager.php',
        'ApiCreateAccount' => __DIR__ . '/includes/api/ApiCreateAccount.php',
+       'ApiCSPReport' => __DIR__ . '/includes/api/ApiCSPReport.php',
        'ApiDelete' => __DIR__ . '/includes/api/ApiDelete.php',
        'ApiDisabled' => __DIR__ . '/includes/api/ApiDisabled.php',
        'ApiEditPage' => __DIR__ . '/includes/api/ApiEditPage.php',
diff --git a/includes/api/ApiCSPReport.php b/includes/api/ApiCSPReport.php
new file mode 100644 (file)
index 0000000..5271996
--- /dev/null
@@ -0,0 +1,224 @@
+<?php
+/**
+ * Copyright © 2015 Brian Wolff
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+use MediaWiki\Logger\LoggerFactory;
+
+/**
+ * Api module to receive and log CSP violation reports
+ *
+ * @ingroup API
+ */
+class ApiCSPReport extends ApiBase {
+
+       private $log;
+
+       /**
+        * These reports should be small. Ignore super big reports out of paranoia
+        */
+       const MAX_POST_SIZE = 8192;
+
+       /**
+        * Logs a content-security-policy violation report from web browser.
+        */
+       public function execute() {
+               $reportOnly = $this->getParameter( 'reportonly' );
+               $logname = $reportOnly ? 'csp-report-only' : 'csp';
+               $this->log = LoggerFactory::getInstance( $logname );
+               $userAgent = $this->getRequest()->getHeader( 'user-agent' );
+
+               $this->verifyPostBodyOk();
+               $report = $this->getReport();
+               $flags = $this->getFlags( $report );
+
+               $warningText = $this->generateLogLine( $flags, $report );
+               $this->logReport( $flags, $warningText, [
+                       // XXX Is it ok to put untrusted data into log??
+                       'csp-report' => $report,
+                       'method' => __METHOD__,
+                       'user' => $this->getUser()->getName(),
+                       'user-agent' => $userAgent,
+                       'source' => $this->getParameter( 'source' ),
+               ] );
+               $this->getResult()->addValue( null, $this->getModuleName(), 'success' );
+       }
+
+       /**
+        * Log CSP report, with a different severity depending on $flags
+        * @param $flags Array Flags for this report
+        * @param $logLine String text of log entry
+        * @param $context Array logging context
+        */
+       private function logReport( $flags, $logLine, $context ) {
+               if ( in_array( 'false-positive', $flags ) ) {
+                       // These reports probably don't matter much
+                       $this->log->debug( $logLine, $context );
+               } else {
+                       // Normal report.
+                       $this->log->warning( $logLine, $context );
+               }
+       }
+
+       /**
+        * Get extra notes about the report.
+        *
+        * @param $report Array The CSP report
+        * @return Array
+        */
+       private function getFlags( $report ) {
+               $reportOnly = $this->getParameter( 'reportonly' );
+               $userAgent = $this->getRequest()->getHeader( 'user-agent' );
+               $source = $this->getParameter( 'source' );
+
+               $flags = [];
+               if ( $source !== 'internal' ) {
+                       $flags[] = 'source=' . $source;
+               }
+               if ( $reportOnly ) {
+                       $flags[] = 'report-only';
+               }
+               return $flags;
+       }
+
+       /**
+        * Output an api error if post body is obviously not OK.
+        */
+       private function verifyPostBodyOk() {
+               $req = $this->getRequest();
+               $contentType = $req->getHeader( 'content-type' );
+               if ( $contentType !== 'application/json'
+                       && $contentType !=='application/csp-report'
+               ) {
+                       $this->error( 'wrongformat', __METHOD__ );
+               }
+               if ( $req->getHeader( 'content-length' ) > self::MAX_POST_SIZE ) {
+                       $this->error( 'toobig', __METHOD__ );
+               }
+       }
+
+       /**
+        * Get the report from post body and turn into associative array.
+        *
+        * @return Array
+        */
+       private function getReport() {
+               $postBody = $this->getRequest()->getRawInput();
+               if ( strlen( $postBody ) > self::MAX_POST_SIZE ) {
+                       // paranoia, already checked content-length earlier.
+                       $this->error( 'toobig', __METHOD__ );
+               }
+               $status = FormatJson::parse( $postBody, FormatJson::FORCE_ASSOC );
+               if ( !$status->isGood() ) {
+                       list( $code, ) = $this->getErrorFromStatus( $status );
+                       $this->error( $code, __METHOD__ );
+               }
+
+               $report = $status->getValue();
+
+               if ( !isset( $report['csp-report'] ) ) {
+                       $this->error( 'missingkey', __METHOD__ );
+               }
+               return $report['csp-report'];
+       }
+
+       /**
+        * Get text of log line.
+        *
+        * @param $flags Array of additional markers for this report
+        * @param $report Array the csp report
+        * @return String Text to put in log
+        */
+       private function generateLogLine( $flags, $report ) {
+               $flagText = '';
+               if ( $flags ) {
+                       $flagText = '[' . implode( $flags, ', ' ) . ']';
+               }
+
+               $blockedFile = isset( $report['blocked-uri'] ) ? $report['blocked-uri'] : 'n/a';
+               $page = isset( $report['document-uri'] ) ? $report['document-uri'] : 'n/a';
+               $line = isset( $report['line-number'] ) ? ':' . $report['line-number'] : '';
+               $warningText = $flagText .
+                       ' Received CSP report: <' . $blockedFile .
+                       '> blocked from being loaded on <' . $page . '>' . $line;
+               return $warningText;
+       }
+
+       /**
+        * Stop processing the request, and output/log an error
+        *
+        * @param $code String error code
+        * @param $method String method that made error
+        * @throws UsageException Always
+        */
+       private function error( $code, $method ) {
+               $this->log->info( 'Error reading CSP report: ' . $code, [
+                       'method' => $method,
+                       'user-agent' => $this->getRequest()->getHeader( 'user-agent' )
+               ] );
+               // 500 so it shows up in browser's developer console.
+               $this->dieUsage( "Error processing CSP report: $code", 'cspreport-' . $code, 500 );
+       }
+
+       public function getAllowedParams() {
+               return [
+                       'reportonly' => [
+                               ApiBase::PARAM_TYPE => 'boolean',
+                               ApiBase::PARAM_DFLT => false
+                       ],
+                       'source' => [
+                               ApiBase::PARAM_TYPE => 'string',
+                               ApiBase::PARAM_DFLT => 'internal',
+                               ApiBase::PARAM_REQUIRED => false
+                       ]
+               ];
+       }
+
+       public function mustBePosted() {
+               return true;
+       }
+
+       public function isWriteMode() {
+               return false;
+       }
+
+       /**
+        * Mark as internal. This isn't meant to be used by normal api users
+        */
+       public function isInternal() {
+               return true;
+       }
+
+       /**
+        * Even if you don't have read rights, we still want your report.
+        */
+       public function isReadMode() {
+               return false;
+       }
+
+       /**
+        * Doesn't touch db, so max lag should be rather irrelavent.
+        *
+        * Also, this makes sure that reports aren't lost during lag events.
+        */
+       public function shouldCheckMaxLag() {
+               return false;
+       }
+}
index c8601a0..a9541d3 100644 (file)
@@ -71,6 +71,7 @@ class ApiMain extends ApiBase {
                'compare' => 'ApiComparePages',
                'tokens' => 'ApiTokens',
                'checktoken' => 'ApiCheckToken',
+               'cspreport' => 'ApiCSPReport',
 
                // Write modules
                'purge' => 'ApiPurge',
index 5124955..24b66ab 100644 (file)
@@ -73,7 +73,9 @@
        "apihelp-createaccount-param-language": "Language code to set as default for the user (optional, defaults to content language).",
        "apihelp-createaccount-example-pass": "Create user <kbd>testuser</kbd> with password <kbd>test123</kbd>.",
        "apihelp-createaccount-example-mail": "Create user <kbd>testmailuser</kbd> and email a randomly-generated password.",
-
+       "apihelp-cspreport-description": "Used by browsers to report violations of the Content Security Policy. This module should never be used, except when used automatically by a CSP compliant web browser.",
+       "apihelp-cspreport-param-reportonly": "Mark as being a report from a monitoring policy, not an enforced policy",
+       "apihelp-cspreport-param-source": "What generated the CSP header that triggered this report",
        "apihelp-delete-description": "Delete a page.",
        "apihelp-delete-param-title": "Title of the page to delete. Cannot be used together with <var>$1pageid</var>.",
        "apihelp-delete-param-pageid": "Page ID of the page to delete. Cannot be used together with <var>$1title</var>.",
index ed9952f..6c47aa4 100644 (file)
@@ -75,6 +75,9 @@
        "apihelp-createaccount-param-language": "{{doc-apihelp-param|createaccount|language}}",
        "apihelp-createaccount-example-pass": "{{doc-apihelp-example|createaccount}}",
        "apihelp-createaccount-example-mail": "{{doc-apihelp-example|createaccount}}",
+       "apihelp-cspreport-description": "{{doc-apihelp-description|cspreport}}",
+       "apihelp-cspreport-param-reportonly": "{{doc-apihelp-param|cspreport|reportonly}}",
+       "apihelp-cspreport-param-source": "{{doc-apihelp-param|cspreport|source}}",
        "apihelp-delete-description": "{{doc-apihelp-description|delete}}",
        "apihelp-delete-param-title": "{{doc-apihelp-param|delete|title}}",
        "apihelp-delete-param-pageid": "{{doc-apihelp-param|delete|pageid}}",