path: root/IkiWiki/Plugin/htmlscrubber.pm

#!/usr/bin/perl
package IkiWiki::Plugin::htmlscrubber;

use warnings;
use strict;
use IkiWiki 3.00;

# This regexp matches urls that are in a known safe scheme.
# Feel free to use it from other plugins.
our $safe_url_regexp;

sub import {
    hook(type => "getsetup", id => "htmlscrubber", call => \&getsetup);
    hook(type => "sanitize", id => "htmlscrubber", call => \&sanitize);

    # Only known uri schemes are allowed to avoid all the ways of
    # embedding javascrpt.
    # List at http://en.wikipedia.org/wiki/URI_scheme
    my $uri_schemes=join("|", map quotemeta,
        # IANA registered schemes
        "http", "https", "ftp", "mailto", "file", "telnet", "gopher",
        "aaa", "aaas", "acap",  "cap", "cid", "crid", 
        "dav", "dict", "dns", "fax", "go", "h323", "im", "imap",
        "ldap", "mid", "news", "nfs", "nntp", "pop", "pres",
        "sip", "sips", "snmp", "tel", "urn", "wais", "xmpp",
        "z39.50r", "z39.50s",
        # Selected unofficial schemes
        "aim", "callto", "cvs", "ed2k", "feed", "fish", "gg",
        "irc", "ircs", "lastfm", "ldaps", "magnet", "mms",
        "msnim", "notes", "rsync", "secondlife", "skype", "ssh",
        "sftp", "smb", "sms", "snews", "webcal", "ymsgr",
    );
    # data is a special case. Allow a few data:image/ types,
    # but disallow data:text/javascript and everything else.
    $safe_url_regexp=qr/^(?:(?:$uri_schemes):|data:image\/(?:png|jpeg|gif)|[^:]+(?:$|[\/\?]))/i;
}

sub getsetup () {
    return
        plugin => {
            safe => 1,
            rebuild => undef,
            section => "core",
        },
        htmlscrubber_skip => {
            type => "pagespec",
            example => "!*/Discussion",
            description => "PageSpec specifying pages not to scrub",
            link => "ikiwiki/PageSpec",
            safe => 1,
            rebuild => undef,
        },
}

sub sanitize (@) {
    my %params=@_;

    if (exists $config{htmlscrubber_skip} &&
        length $config{htmlscrubber_skip} &&
        exists $params{destpage} &&
        pagespec_match($params{destpage}, $config{htmlscrubber_skip})) {
        return $params{content};
    }

    return scrubber()->scrub($params{content});
}

my $_scrubber;
sub scrubber {
    return $_scrubber if defined $_scrubber;

    eval q{use HTML::Scrubber};
    error($@) if $@;
    # Lists based on http://feedparser.org/docs/html-sanitization.html
    # With html 5 video and audio tags added.
    $_scrubber = HTML::Scrubber->new(
        allow => [qw{
            a abbr acronym address area b big blockquote br br/
            button caption center cite code col colgroup dd del
            dfn dir div dl dt em fieldset font form h1 h2 h3 h4
            h5 h6 hr hr/ i img input ins kbd label legend li map
            menu ol optgroup option p p/ pre q s samp select small
            span strike strong sub sup table tbody td textarea
            tfoot th thead tr tt u ul var
            video audio
        }],
        default => [undef, { (
            map { $_ => 1 } qw{
                abbr accept accept-charset accesskey
                align alt axis border cellpadding cellspacing
                char charoff charset checked class
                clear cols colspan color compact coords
                datetime dir disabled enctype for frame
                headers height hreflang hspace id ismap
                label lang maxlength media method
                multiple name nohref noshade nowrap prompt
                readonly rel rev rows rowspan rules scope
                selected shape size span start summary
                tabindex target title type valign
                value vspace width
                autoplay loopstart loopend end
                playcount controls 
            } ),
            "/" => 1, # emit proper <hr /> XHTML
            href => $safe_url_regexp,
            src => $safe_url_regexp,
            action => $safe_url_regexp,
            cite => $safe_url_regexp,
            longdesc => $safe_url_regexp,
            poster => $safe_url_regexp,
            usemap => $safe_url_regexp,
        }],
    );
    return $_scrubber;
}

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