Accidentally committed experimental version of robots.nse

scripts/robots.nse

@@ -1,71 +1,39 @@
 require('shortport')
 require('strbuf')
-require('stdnse')
 require('listop')
 
 id = "robots.txt"
 author = "Eddie Bell <ejlbell@gmail.com>"
-description = "Probes for a http servers robots.txt file and returns a summary of it"
+description = "Download a http servers robots.txt file and display all disallowed entries"
 license = "See nmaps COPYING for licence"
-categories = {"intrusive"}
+categories = {"safe"}
 runlevel = 1.0
 
 portrule = shortport.port_or_service(80, "http")
+local last_len = 0
 
--- validates a robots.txt according to IETF conventions. Note
+-- split the output in 40 character lines 
--- there is no standard governing robots.txt files but the
+local function buildOutput(output, w)
--- IETF document is the closes thing
+	local len = string.len(w)
-local function validate(robot_txt)
+
-	local function valid(line)
+	for i,v in ipairs(output) do
-		return string.find(line, '^#.*') or
+		if w == v then return nil end
-		string.find(line, '^user%-agent:.*') or
-		string.find(line, '^disallow:.*') or
-		string.find(line, '^allow:.') or
-		string.len(line) == 0
 	end
 	
-	-- test if the robots.txt data is valid
+	if last_len == 0 or last_len + len <= 40 then
-	local results = listop.map(valid, robot_txt)
+		last_len = last_len + len
-	local invalid_lines = listop.filter(function(x) return not x end, results)
+	else
-	return listop.is_empty(invalid_lines)
+		output = output .. '\n'
-end
+		last_len = 0
-
-local function analyse_robots(r_data, output)
-	local function is_present(line)
-		if string.find(line, '^#.*') then return 1 
-		elseif string.find(line, '^user%-agent:.*') then return 2
-		elseif string.find(line, '^disallow:.*') then return 3
-		else return 0
-		end
 	end
 
-	local function gen_match(match_id, present)
+	output = output .. w 
-		return listop.filter(function(x) return x == match_id end, present)
+	output = output .. ' '
-	end
-
-	-- parse robots file and check for its elements
-	local robot_txt = stdnse.strsplit("\n", r_data)
-	local present = listop.map(is_present, robot_txt)
-	
-	if not listop.is_empty(gen_match(1, present)) then
-		output = output .. "! contains disallowed entries\n"
-	end
-
-	if not listop.is_empty(gen_match(2, present)) then
-		output = output .. "! mentions specific user-agents\n"
-	end
-
-	if not listop.is_empty(gen_match(3, present)) then
-		output = output .. "! contains comments, which may be interesting\n"
-	end
-
-	if not validate(robot_txt) then
-		output = output .. "! does not adhere to IETF conventions\n"
-	end
 end
 
 action = function(host, port)
-	local lines, status, soc, query, s, e
+	local soc, lines, status
+
 	local catch = function() soc.close() end
 	local try = nmap.new_try(catch)
 
@@ -74,8 +42,7 @@ action = function(host, port)
 	soc:set_timeout(4000)
 	try(soc:connect(host.ip, port.number))
 
-	-- test if robots.txt is present
+	local query = strbuf.new()
-	query = strbuf.new()
 	query = query .. "GET /robots.txt HTTP/1.1"
 	query = query .. "Accept: */*"
 	query = query .. "Accept-Language: en"
@@ -85,56 +52,25 @@ action = function(host, port)
 	try(soc:send(strbuf.dump(query, '\r\n')))
 
 	local response = strbuf.new()
-	local output = strbuf.new()
-
 	while true do
 		status, lines = soc:receive_lines(1)
 		if not status then break end
 		response = response .. lines
 	end
 
-	local hdata = strbuf.dump(response, '\n')
+	if not string.find(strbuf.dump(response), "HTTP/1.1 200 OK") then
-
-	if string.find(hdata, "HTTP/1.1 200 OK") then
-		for w in string.gmatch(hdata, "Content%-Type:%s*([^\r\n]*)\r\n") do
-			output = output .. w .. '\n'
-		end
-
-		-- remove http protocol stuff and analyse robots.txt file
-		s, e = string.find(hdata, "\r\n\r\n")
-		hdata = string.lower(hdata)
-		if e then analyse_robots(string.sub(hdata, e), output) end
-	end
-
-	soc:close()
-	try(soc:connect(host.ip, port.number))
-	strbuf.clear(query)
-	strbuf.clear(response)
-
-	-- test to see if info.txt is present
-	query = query .. "GET /info.txt HTTP/1.1"
-	query = query .. "Accept: */*"
-	query = query .. "Accept-Language: en"
-	query = query .. "User-Agent: Nmap NSE"
-	query = query .. "Host: " .. host.ip .. ":" .. port.number
-	query = query .. '\r\n\r\n';
-	try(soc:send(strbuf.dump(query, '\r\n')))
-
-	while true do
-		status, lines = soc:receive_lines(1)
-		if not status then break end
-		response = response .. lines
-	end
-
-	if string.find(strbuf.dump(response), "HTTP/1.1 200 OK") then
-		output = output .. "\n! info.txt is present\n"
-	end
-
-	soc:close()
-
-	if listop.is_empty(output) then 
 		return nil
-	else 
+	end
+
+	-- parse all disallowed entries
+	local output = strbuf.new()
+	for w in string.gmatch(strbuf.dump(response, '\n'), "Disallow:%s*([^\n]*)\n") do
+			buildOutput(output, w)
+	end
+
+	if not listop.is_empty(output) then
 		return strbuf.dump(output)
 	end
+
+	return nil
 end