feature 1915: add protection on user registration against robots

git-svn-id: http://piwigo.org/svn/trunk@7495 68402e56-0260-453c-a942-63ccdbb3a9ee

4 files changed, 32 insertions, 33 deletions

diff --git a/include/functions.inc.php b/include/functions.inc.php
index a994fdb95..61db92ab5 100644
--- a/include/functions.inc.php
+++ b/include/functions.inc.php
@@ -1333,25 +1333,37 @@ function secure_directory($dir)
 }
 
 /**
- * returns a "secret key" that is to be sent back when a user enters a comment
+ * returns a "secret key" that is to be sent back when a user posts a form
  *
- * @param int image_id
+ * @param int valid_after_seconds - key validity start time from now
  */
-function get_comment_post_key($image_id)
+function get_ephemeral_key($valid_after_seconds, $aditionnal_data_to_hash = '')
 {
-  global $conf;
-
-  $time = time();
+	global $conf;
+	$time = round(microtime(true), 1);
+	return $time.':'.$valid_after_seconds.':'
+		.hash_hmac(
+			'md5', 
+			$time.substr($_SERVER['REMOTE_ADDR'],0,5).$valid_after_seconds.$aditionnal_data_to_hash, 
+			$conf['secret_key']);
+}
 
-  return sprintf(
-    '%s:%s',
-    $time,
-    hash_hmac(
-      'md5',
-      $time.':'.$image_id,
-      $conf['secret_key']
-      )
-    );
+function verify_ephemeral_key($key, $aditionnal_data_to_hash = '')
+{
+	global $conf;
+	$time = microtime(true);
+	$key = explode( ':', @$key );
+	if ( count($key)!=3
+		or $key[0]>$time-(float)$key[1] // page must have been retrieved more than X sec ago
+		or $key[0]<$time-3600 // 60 minutes expiration
+		or hash_hmac(
+			  'md5', $key[0].substr($_SERVER['REMOTE_ADDR'],0,5).$key[1].$aditionnal_data_to_hash, $conf['secret_key']
+			) != $key[2]
+	  )
+	{
+		return false;
+	}
+	return true;
 }
 
 /**
diff --git a/include/functions_comment.inc.php b/include/functions_comment.inc.php
index 7f2fd9257..d5b403b8e 100644
--- a/include/functions_comment.inc.php
+++ b/include/functions_comment.inc.php
@@ -119,14 +119,7 @@ SELECT COUNT(*) AS user_exists
     $comment_action='reject';
   }
 
-  $key = explode( ':', @$key );
-  if ( count($key)!=2
-        or $key[0]>time()-2 // page must have been retrieved more than 2 sec ago
-        or $key[0]<time()-3600 // 60 minutes expiration
-        or hash_hmac(
-              'md5', $key[0].':'.$comm['image_id'], $conf['secret_key']
-            ) != $key[1]
-      )
+  if ( !verify_ephemeral_key(@$key, $comm['image_id']) )
   {
     $comment_action='reject';
   }
@@ -248,13 +241,7 @@ function update_user_comment($comment, $post_key)
 
   $comment_action = 'validate';
 
-  $key = explode( ':', $post_key );
-  if ( count($key)!=2
-       or $key[0]>time()-2 // page must have been retrieved more than 2 sec ago
-       or $key[0]<time()-3600 // 60 minutes expiration
-       or hash_hmac('md5', $key[0].':'.$comment['image_id'], $conf['secret_key']
-		    ) != $key[1]
-       )
+  if ( !verify_ephemeral_key($post_key, $comment['image_id']) )
   {
     $comment_action='reject';
   }
diff --git a/include/picture_comment.inc.php b/include/picture_comment.inc.php
index cc4970a34..adf928bbb 100644
--- a/include/picture_comment.inc.php
+++ b/include/picture_comment.inc.php
@@ -198,7 +198,7 @@ SELECT
 	if (isset($edit_comment) and ($row['id'] == $edit_comment))
 	{
 	  $tpl_comment['IN_EDIT'] = true;
-	  $key = get_comment_post_key($page['image_id']);
+	  $key = get_comment_post_key(2, $page['image_id']);
 	  $tpl_comment['KEY'] = $key;
 	  $tpl_comment['CONTENT'] = $row['content'];
 	}
@@ -233,7 +233,7 @@ SELECT
 
   if ($show_add_comment_form)
   {
-    $key = get_comment_post_key($page['image_id']);
+    $key = get_ephemeral_key(3, $page['image_id']);
     $content = '';
     if ('reject'===@$comment_action)
     {
diff --git a/include/ws_functions.inc.php b/include/ws_functions.inc.php
index ec9227d49..3cc0fc3a3 100644
--- a/include/ws_functions.inc.php
+++ b/include/ws_functions.inc.php
@@ -725,7 +725,7 @@ SELECT id, date, author, content
       )
   {
     $comment_post_data['author'] = stripslashes($user['username']);
-    $comment_post_data['key'] = get_comment_post_key($params['image_id']);
+    $comment_post_data['key'] = get_ephemeral_key(2, $params['image_id']);
   }
 
   $ret = $image_row;