From 1a65464490533becd56c2b3006a076551ff673bd Mon Sep 17 00:00:00 2001
From: Aaron Campbell <aaron@xavisys.com>
Date: Tue, 16 May 2017 14:56:48 +0000
Subject: [PATCH] Add nonce for updating file system credentials.

Merges [40723] to 4.1 branch.

Built from https://develop.svn.wordpress.org/branches/4.1@40730


git-svn-id: http://core.svn.wordpress.org/branches/4.1@40588 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-admin/includes/file.php | 37 +++++++++++++++++++++++++++----------
 1 file changed, 27 insertions(+), 10 deletions(-)

diff --git a/wp-admin/includes/file.php b/wp-admin/includes/file.php
index 156437fac6..d08de2754c 100644
--- a/wp-admin/includes/file.php
+++ b/wp-admin/includes/file.php
@@ -1018,14 +1018,28 @@ function request_filesystem_credentials($form_post, $type = '', $error = false,
 
 	$credentials = get_option('ftp_credentials', array( 'hostname' => '', 'username' => ''));
 
+	$submitted_form = wp_unslash( $_POST );
+
+	// Verify nonce, or unset submitted form field values on failure
+	if ( ! isset( $_POST['_fs_nonce'] ) || ! wp_verify_nonce( $_POST['_fs_nonce'], 'filesystem-credentials' ) ) {
+		unset(
+			$submitted_form['hostname'],
+			$submitted_form['username'],
+			$submitted_form['password'],
+			$submitted_form['public_key'],
+			$submitted_form['private_key'],
+			$submitted_form['connection_type']
+		);
+	}
+
 	// If defined, set it to that, Else, If POST'd, set it to that, If not, Set it to whatever it previously was(saved details in option)
-	$credentials['hostname'] = defined('FTP_HOST') ? FTP_HOST : (!empty($_POST['hostname']) ? wp_unslash( $_POST['hostname'] ) : $credentials['hostname']);
-	$credentials['username'] = defined('FTP_USER') ? FTP_USER : (!empty($_POST['username']) ? wp_unslash( $_POST['username'] ) : $credentials['username']);
-	$credentials['password'] = defined('FTP_PASS') ? FTP_PASS : (!empty($_POST['password']) ? wp_unslash( $_POST['password'] ) : '');
+	$credentials['hostname'] = defined('FTP_HOST') ? FTP_HOST : (!empty($submitted_form['hostname']) ? $submitted_form['hostname'] : $credentials['hostname']);
+	$credentials['username'] = defined('FTP_USER') ? FTP_USER : (!empty($submitted_form['username']) ? $submitted_form['username'] : $credentials['username']);
+	$credentials['password'] = defined('FTP_PASS') ? FTP_PASS : (!empty($submitted_form['password']) ? $submitted_form['password'] : '');
 
 	// Check to see if we are setting the public/private keys for ssh
-	$credentials['public_key'] = defined('FTP_PUBKEY') ? FTP_PUBKEY : (!empty($_POST['public_key']) ? wp_unslash( $_POST['public_key'] ) : '');
-	$credentials['private_key'] = defined('FTP_PRIKEY') ? FTP_PRIKEY : (!empty($_POST['private_key']) ? wp_unslash( $_POST['private_key'] ) : '');
+	$credentials['public_key'] = defined('FTP_PUBKEY') ? FTP_PUBKEY : (!empty($submitted_form['public_key']) ? $submitted_form['public_key'] : '');
+	$credentials['private_key'] = defined('FTP_PRIKEY') ? FTP_PRIKEY : (!empty($submitted_form['private_key']) ? $submitted_form['private_key'] : '');
 
 	// Sanitize the hostname, Some people might pass in odd-data:
 	$credentials['hostname'] = preg_replace('|\w+://|', '', $credentials['hostname']); //Strip any schemes off
@@ -1042,8 +1056,8 @@ function request_filesystem_credentials($form_post, $type = '', $error = false,
 		$credentials['connection_type'] = 'ssh';
 	else if ( (defined('FTP_SSL') && FTP_SSL) && 'ftpext' == $type ) //Only the FTP Extension understands SSL
 		$credentials['connection_type'] = 'ftps';
-	else if ( !empty($_POST['connection_type']) )
-		$credentials['connection_type'] = wp_unslash( $_POST['connection_type'] );
+	else if ( !empty($submitted_form['connection_type']) )
+		$credentials['connection_type'] = $submitted_form['connection_type'];
 	else if ( !isset($credentials['connection_type']) ) //All else fails (And it's not defaulted to something else saved), Default to FTP
 		$credentials['connection_type'] = 'ftp';
 
@@ -1183,11 +1197,14 @@ jQuery(function($){
 
 <?php
 foreach ( (array) $extra_fields as $field ) {
-	if ( isset( $_POST[ $field ] ) )
-		echo '<input type="hidden" name="' . esc_attr( $field ) . '" value="' . esc_attr( wp_unslash( $_POST[ $field ] ) ) . '" />';
+	if ( isset( $submitted_form[ $field ] ) )
+		echo '<input type="hidden" name="' . esc_attr( $field ) . '" value="' . esc_attr( $submitted_form[ $field ] ) . '" />';
 }
-submit_button( __( 'Proceed' ), 'button', 'upgrade' );
 ?>
+	<p class="request-filesystem-credentials-action-buttons">
+		<?php wp_nonce_field( 'filesystem-credentials', '_fs_nonce', false, true ); ?>
+		<?php submit_button( __( 'Proceed' ), 'button', 'upgrade', false ); ?>
+	</p>
 </div>
 </form>
 <?php