MyBB Hacks

• Admins cannot enter PHP code using <?php ?> tags
• Conditionals in <if> and <elseif> tags are checked to ensure that they are "safe" (see below)
• file_get_contents function has been removed from the allowable <func ...>...</func> shortcuts
• There's a new <?=...?> tag to print out the result of a "safe" PHP expression; although this is a tag, only PHP expressions may exist inside (do not terminate expressions with a semicolon), so you cannot nest other tags inside this
  Example (prints 123654321):
  HTML Code

  123<?=substr("987654321", 3)?>

  ---

• There's also a new <setvar name>...</setvar> tag which can set variables; for safety reasons, these are actually stored in a $tplvars array.  Examples:
  (just prints some text)
  
  HTML Code

  <setvar uselesstext>"some text"</setvar> {$tplvars['uselesstext']}

  ---

  (prints out the username of the user with UID of 2)
  

  HTML Code

  <setvar user2>get_user(2)</setvar> <func htmlspecialchars_uni>{$tplvars['user2']['username']}</func>

  ---

• no assignment/modification operators (=, +=, |=, ++ etc) allowed
• no statements such as include, exit, eval etc are allowed
• no special constants such as PHP_OS, PHP_LIBDIR etc are allowed
• backtick (`) operator not allowed
• heredoc type strings not allowed (takes too much effort to handle) - use double quoted strings instead
• double quoted strings may not contain the "{" character (takes too much effort to handle) - use string concatenation instead
• array and object typecasting not allowed
• no variable functions or method calls allowed
• single line comments (//, #) not allowed
• only some functions are allowed - see inc/plugins/phptpl_allowed_funcs.txt for a list of allowed functions
  

<?=phptpl_eval_expr('1+1')?>

phptpl_eval_text
This evaluates a text string like template text, supporting conditional constructs etc.
Example:

<?=phptpl_eval_text('Welcome {$GLOBALS[\'mybb\']->user[\'username\']}!  <'.'if $GLOBALS[\'mybb\']->usergroup[\'cancp\'] then>You are an administrator.</'.'if>')?>

Note that the <if> ... </if> tags are broken up to prevent them being parsed as tags to be used in the actual template.

Note about scope
Both of the above functions are, PHP functions, so they will have function scope and won't carry over the scope you're calling them from.  Essentially, this means you will probably need to globalise all variables to use them.