From 1786b60fe75e889c58cecaf78305d342beabfa00 Mon Sep 17 00:00:00 2001
From: Joey Hess <joey@gnu.kitenet.net>
Date: Fri, 12 Mar 2010 15:20:25 -0500
Subject: [PATCH] htmlscrubber: Security fix: In data:image/* uris, only allow
 a few whitelisted image types. No svg.

---
 IkiWiki/Plugin/htmlscrubber.pm |  6 +++---
 debian/changelog               |  7 +++++++
 doc/security.mdwn              | 25 ++++++++++++++++++++++++-
 3 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/IkiWiki/Plugin/htmlscrubber.pm b/IkiWiki/Plugin/htmlscrubber.pm
index 3bdaccea1..9530d8708 100644
--- a/IkiWiki/Plugin/htmlscrubber.pm
+++ b/IkiWiki/Plugin/htmlscrubber.pm
@@ -29,9 +29,9 @@ sub import { #{{{
 		"msnim", "notes", "rsync", "secondlife", "skype", "ssh",
 		"sftp", "smb", "sms", "snews", "webcal", "ymsgr",
 	);
-	# data is a special case. Allow data:image/*, but
-	# disallow data:text/javascript and everything else.
-	$safe_url_regexp=qr/^(?:(?:$uri_schemes):|data:image\/|[^:]+(?:$|\/))/i;
+	# 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 sanitize (@) { #{{{
diff --git a/debian/changelog b/debian/changelog
index 2121f812b..c01b697e3 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,10 @@
+ikiwiki (2.53.5) stable-security; urgency=high
+
+  * htmlscrubber: Security fix: In data:image/* uris, only allow a few
+    whitelisted image types. No svg.
+
+ -- Joey Hess <joeyh@debian.org>  Fri, 12 Mar 2010 15:19:29 -0500
+
 ikiwiki (2.53.4) stable-security; urgency=high
 
   * teximg: Replace the insufficient blacklist with the built-in security
diff --git a/doc/security.mdwn b/doc/security.mdwn
index 403de81de..2eca735b2 100644
--- a/doc/security.mdwn
+++ b/doc/security.mdwn
@@ -416,4 +416,27 @@ can cause it to crash. This can potentially be used for a denial of service
 attack.
 
 intrigeri discovered this problem on 12 Nov 2008 and a patch put in place
-later that day.
+later that day, in version 2.70. The fix was backported to testing as version
+2.53.3, and to stable as version 1.33.7.
+
+## Insufficient blacklisting in teximg plugin
+
+Josh Triplett discovered on 28 Aug 2009 that the teximg plugin's
+blacklisting of insecure TeX commands was insufficient; it could be
+bypassed and used to read arbitrary files. This was fixed by
+enabling TeX configuration options that disallow unsafe TeX commands.
+The fix was released on 30 Aug 2009 in version 3.1415926, and was
+backported to stable in version 2.53.4. If you use the teximg plugin,
+I recommend upgrading. ([[!cve CVE-2009-2944]])
+
+## javascript insertion via svg uris
+
+Ivan Shmakov pointed out that the htmlscrubber allowed `data:image/*` urls,
+including `data:image/svg+xml`. But svg can contain javascript, so that is
+unsafe.
+
+This hole was discovered on 12 March 2010 and fixed the same day
+with the release of ikiwiki 3.20100312.
+A fix was also backported to Debian etch, as version 2.53.5. I recommend
+upgrading to one of these versions if your wiki can be edited by third
+parties.
-- 
2.39.2