implemented html sanitisation

1 files changed, 30 insertions, 0 deletions

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+When run with the --sanitize switch, which is turned on by default (see
+[[usage]], ikiwiki sanitizes the html on pages it renders to avoid XSS
+attacks and the like.
+
+ikiwiki excludes all html tags and attributes except for those that are
+whitelisted using the same lists as used by Mark Pilgrim's Universal Feed
+Parser, documented at <http://feedparser.org/docs/html-sanitization.html>.
+Notably it strips `style`, `link`, and the `style` attribute.
+
+ikiwiki uses the HTML::Scrubber perl module to perform its html
+sanitisation, and this perl module also deals with various entity encoding
+tricks.
+
+While I beleive that this makes ikiwiki as resistant to malicious html
+content as anything else on the web, I cannot guarantee that it will
+actually protect every user of every browser from every browser security
+hole, badly designed feature, etc. I can provide NO WARRANTY, like it says
+in ikiwiki's [[GPL]] license. 
+
+The web's security model is *fundamntally broken*; ikiwiki's HTML
+sanitisation is only a patch on the underlying gaping hole that is your web
+browser.
+
+----
+
+Some examples of embedded javascript that won't be let through.
+
+<span style="background: url(javascript:window.location='http://example.org/')">test</span>
+<span style="&#x61;&#x6e;&#x79;&#x3a;&#x20;&#x65;&#x78;&#x70;&#x72;&#x65;&#x73;&#x73;&#x69;&#x6f;&#x6e;&#x28;&#x77;&#x69;&#x6e;&#x64;&#x6f;&#x77;&#x2e;&#x6c;&#x6f;&#x63;&#x61;&#x74;&#x69;&#x6f;&#x6e;&#x3d;&#x27;&#x68;&#x74;&#x74;&#x70;&#x3a;&#x2f;&#x2f;&#x65;&#x78;&#x61;&#x6d;&#x70;&#x6c;&#x65;&#x2e;&#x6f;&#x72;&#x67;&#x2f;&#x27;&#x29;">test</span>
+<span style="&#97;&#110;&#121;&#58;&#32;&#101;&#120;&#112;&#114;&#101;&#115;&#115;&#105;&#111;&#110;&#40;&#119;&#105;&#110;&#100;&#111;&#119;&#46;&#108;&#111;&#99;&#97;&#116;&#105;&#111;&#110;&#61;&#39;&#104;&#116;&#116;&#112;&#58;&#47;&#47;&#101;&#120;&#97;&#109;&#112;&#108;&#101;&#46;&#111;&#114;&#103;&#47;&#39;&#41;">test</span>