elif property == 'info':

            if val <> mlist.info:

                if Utils.suspiciousHTML(val):

                    doc.addError(_("""The <b>info</b> attribute you saved

contains suspicious HTML that could potentially expose your users to cross-site

scripting attacks.  This change has therefore been rejected.  If you still want

to make these changes, you must have shell access to your Mailman server.

This change can be made with bin/withlist or with bin/config_list by setting

mlist.info.

                        """))

                else:

                    mlist.info = val

# Patterns and functions to flag possible XSS attacks in HTML.

# This list is compiled from information at http://ha.ckers.org/xss.html,

# http://www.quirksmode.org/js/events_compinfo.html,

# http://www.htmlref.com/reference/appa/events1.htm,

# http://lxr.mozilla.org/mozilla/source/content/events/src/nsDOMEvent.cpp#59,

# http://www.w3.org/TR/DOM-Level-2-Events/events.html and

# http://www.xulplanet.com/references/elemref/ref_EventHandlers.html

# Many thanks are due to Moritz Naumann for his assistance with this.

_badwords = [

    '<i?frame',

    '<link',

    '<meta',

    '<script',

    r'(?:^|\W)j(?:ava)?script(?:\W|$)',

    r'(?:^|\W)vbs(?:cript)?(?:\W|$)',

    r'(?:^|\W)domactivate(?:\W|$)',

    r'(?:^|\W)domattrmodified(?:\W|$)',

    r'(?:^|\W)domcharacterdatamodified(?:\W|$)',

    r'(?:^|\W)domfocus(?:in|out)(?:\W|$)',

    r'(?:^|\W)dommenuitem(?:in)?active(?:\W|$)',

    r'(?:^|\W)dommousescroll(?:\W|$)',

    r'(?:^|\W)domnodeinserted(?:intodocument)?(?:\W|$)',

    r'(?:^|\W)domnoderemoved(?:fromdocument)?(?:\W|$)',

    r'(?:^|\W)domsubtreemodified(?:\W|$)',

    r'(?:^|\W)fscommand(?:\W|$)',

    r'(?:^|\W)onabort(?:\W|$)',

    r'(?:^|\W)on(?:de)?activate(?:\W|$)',

    r'(?:^|\W)on(?:after|before)print(?:\W|$)',

    r'(?:^|\W)on(?:after|before)update(?:\W|$)',

    r'(?:^|\W)onbefore(?:(?:de)?activate|copy|cut|editfocus|paste)(?:\W|$)',

    r'(?:^|\W)onbeforeunload(?:\W|$)',

    r'(?:^|\W)onbegin(?:\W|$)',

    r'(?:^|\W)onblur(?:\W|$)',

    r'(?:^|\W)onbounce(?:\W|$)',

    r'(?:^|\W)onbroadcast(?:\W|$)',

    r'(?:^|\W)on(?:cell)?change(?:\W|$)',

    r'(?:^|\W)oncheckboxstatechange(?:\W|$)',

    r'(?:^|\W)on(?:dbl)?click(?:\W|$)',

    r'(?:^|\W)onclose(?:\W|$)',

    r'(?:^|\W)oncommand(?:update)?(?:\W|$)',

    r'(?:^|\W)oncomposition(?:end|start)(?:\W|$)',

    r'(?:^|\W)oncontextmenu(?:\W|$)',

    r'(?:^|\W)oncontrolselect(?:\W|$)',

    r'(?:^|\W)oncopy(?:\W|$)',

    r'(?:^|\W)oncut(?:\W|$)',

    r'(?:^|\W)ondataavailable(?:\W|$)',

    r'(?:^|\W)ondataset(?:changed|complete)(?:\W|$)',

    r'(?:^|\W)ondrag(?:drop|end|enter|exit|gesture|leave|over)?(?:\W|$)',

    r'(?:^|\W)ondragstart(?:\W|$)',

    r'(?:^|\W)ondrop(?:\W|$)',

    r'(?:^|\W)onend(?:\W|$)',

    r'(?:^|\W)onerror(?:update)?(?:\W|$)',

    r'(?:^|\W)onfilterchange(?:\W|$)',

    r'(?:^|\W)onfinish(?:\W|$)',

    r'(?:^|\W)onfocus(?:in|out)?(?:\W|$)',

    r'(?:^|\W)onhelp(?:\W|$)',

    r'(?:^|\W)oninput(?:\W|$)',

    r'(?:^|\W)onkey(?:up|down|press)(?:\W|$)',

    r'(?:^|\W)onlayoutcomplete(?:\W|$)',

    r'(?:^|\W)on(?:un)?load(?:\W|$)',

    r'(?:^|\W)onlosecapture(?:\W|$)',

    r'(?:^|\W)onmedia(?:complete|error)(?:\W|$)',

    r'(?:^|\W)onmouse(?:down|enter|leave|move|out|over|up|wheel)(?:\W|$)',

    r'(?:^|\W)onmove(?:end|start)?(?:\W|$)',

    r'(?:^|\W)on(?:off|on)line(?:\W|$)',

    r'(?:^|\W)onoutofsync(?:\W|$)',

    r'(?:^|\W)onoverflow(?:changed)?(?:\W|$)',

    r'(?:^|\W)onpage(?:hide|show)(?:\W|$)',

    r'(?:^|\W)onpaint(?:\W|$)',

    r'(?:^|\W)onpaste(?:\W|$)',

    r'(?:^|\W)onpause(?:\W|$)',

    r'(?:^|\W)onpopup(?:hidden|hiding|showing|shown)(?:\W|$)',

    r'(?:^|\W)onprogress(?:\W|$)',

    r'(?:^|\W)onpropertychange(?:\W|$)',

    r'(?:^|\W)onradiostatechange(?:\W|$)',

    r'(?:^|\W)onreadystatechange(?:\W|$)',

    r'(?:^|\W)onrepeat(?:\W|$)',

    r'(?:^|\W)onreset(?:\W|$)',

    r'(?:^|\W)onresize(?:end|start)?(?:\W|$)',

    r'(?:^|\W)onresume(?:\W|$)',

    r'(?:^|\W)onreverse(?:\W|$)',

    r'(?:^|\W)onrow(?:delete|enter|exit|inserted)(?:\W|$)',

    r'(?:^|\W)onrows(?:delete|enter|inserted)(?:\W|$)',

    r'(?:^|\W)onscroll(?:\W|$)',

    r'(?:^|\W)onseek(?:\W|$)',

    r'(?:^|\W)onselect(?:start)?(?:\W|$)',

    r'(?:^|\W)onselectionchange(?:\W|$)',

    r'(?:^|\W)onstart(?:\W|$)',

    r'(?:^|\W)onstop(?:\W|$)',

    r'(?:^|\W)onsubmit(?:\W|$)',

    r'(?:^|\W)onsync(?:from|to)preference(?:\W|$)',

    r'(?:^|\W)onsyncrestored(?:\W|$)',

    r'(?:^|\W)ontext(?:\W|$)',

    r'(?:^|\W)ontimeerror(?:\W|$)',

    r'(?:^|\W)ontrackchange(?:\W|$)',

    r'(?:^|\W)onunderflow(?:\W|$)',

    r'(?:^|\W)onurlflip(?:\W|$)',

    r'(?:^|\W)seeksegmenttime(?:\W|$)',

    r'(?:^|\W)svgabort(?:\W|$)',

    r'(?:^|\W)svgerror(?:\W|$)',

    r'(?:^|\W)svgload(?:\W|$)',

    r'(?:^|\W)svgresize(?:\W|$)',

    r'(?:^|\W)svgscroll(?:\W|$)',

    r'(?:^|\W)svgunload(?:\W|$)',

    r'(?:^|\W)svgzoom(?:\W|$)',

    ]

# This is the actual re to look for the above patterns

_badhtml = re.compile('|'.join(_badwords), re.IGNORECASE)

# This is used to filter non-printable us-ascii characters, some of which

# can be used to break words to avoid recognition.

_filterchars = re.compile('[\000-\011\013\014\016-\037\177-\237]')

# This is used to recognize '&#' and '%xx' strings for _translate which

# translates them to characters

_encodedchars = re.compile('(&#[0-9]+;?)|(&#x[0-9a-f]+;?)|(%[0-9a-f]{2})',

                           re.IGNORECASE)

def _translate(mo):

    """Translate &#... and %xx encodings into the encoded character."""

    match = mo.group().lower().strip('&#;')

    try:

        if match.startswith('x') or match.startswith('%'):

            val = int(match[1:], 16)

        else:

            val = int(match, 10)

    except ValueError:

        return ''

    if val < 256:

        return chr(val)

    else:

        return ''

def suspiciousHTML(html):

    """Check HTML string for various tags, script language names and

    'onxxx' actions that can be used in XSS attacks.

    Currently, this a very simple minded test.  It just looks for

    patterns without analyzing context.  Thus, it potentially flags lots

    of benign stuff.

    Returns True if anything suspicious found, False otherwise.

    """

    if _badhtml.search(_filterchars.sub(

                       '', _encodedchars.sub(_translate, html))):

        return True

    else:

        return False