3 files changed, 70 insertions, 0 deletions
diff --git a/modules/workarounds/README.rst b/modules/workarounds/README.rst
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+++ b/modules/workarounds/README.rst
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+.. _mod-workarounds:
+
+Workarounds
+-----------
+
+A simple module that alters resolver behavior on specific broken sub-domains.
+Currently it mainly disables case randomization on them.
+
+Running
+^^^^^^^
+.. code-block:: lua
+
+    modules = { 'workarounds < iterate' }
+
diff --git a/modules/workarounds/workarounds.lua b/modules/workarounds/workarounds.lua
new file mode 100644
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+++ b/modules/workarounds/workarounds.lua
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+-- Load dependent module
+if not policy then modules.load('policy') end
+
+local M = {} -- the module
+
+function M.config()
+	policy.add(policy.suffix(policy.FLAGS('NO_0X20'), {
+		--  https://github.com/DNS-OARC/dns-violations/blob/master/2017/DVE-2017-0003.md
+		todname('avqs.mcafee.com'), todname('avts.mcafee.com'),
+
+		--  https://github.com/DNS-OARC/dns-violations/blob/master/2017/DVE-2017-0006.md
+		--  Obtained via a reverse search on {ns1,ns3}.panthercdn.com.
+		todname('cdnga.com'), todname('cdngc.com'), todname('cdngd.com'),
+		todname('cdngl.com'), todname('cdngm.com'),
+		todname('cdngc.net'), todname('panthercdn.com'),
+
+		todname('magazine-fashion.net.'),
+	}))
+end
+
+-- Issue #139: When asking certain nameservers for PTR, disable 0x20.
+-- Just listing the *.in-addr.arpa suffixes would be tedious, as there are many.
+M.layer = {
+	produce = function (state, req)
+		req = kres.request_t(req)
+		local qry = req:current()
+		if qry.stype ~= kres.type.PTR
+			or bit.band(state, bit.bor(kres.FAIL, kres.DONE)) ~= 0
+			then return state -- quick exit in most cases
+		end
+		if qry.flags.AWAIT_CUT or qry.ns.name == nil
+			then return state end
+		local name = kres.dname2str(qry.ns.name)
+		if not name then return state end
+
+		-- The problematic nameservers:
+		-- (1) rdnsN.turktelekom.com.tr.
+		if string.sub(name, 6) == '.turktelekom.com.tr.' then
+			qry.flags.NO_0X20 = true
+			qry.flags.NO_MINIMIZE = true
+			-- ^ NO_MINIMIZE isn't required for success, as kresd will retry
+			-- after getting refused, but it will speed things up.
+
+		-- (2)
+		elseif name == 'dns1.edatel.net.co.' then
+			qry.flags.NO_0X20 = true
+		end
+
+		return state
+	end,
+}
+
+return M
+
diff --git a/modules/workarounds/workarounds.mk b/modules/workarounds/workarounds.mk
new file mode 100644
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+++ b/modules/workarounds/workarounds.mk
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+workarounds_SOURCES := workarounds.lua
+$(call make_lua_module,workarounds)