Move url-encoding to url.build_query

patch from nnposter: http://seclists.org/nmap-dev/2014/q3/427

nselib/url.lua

@@ -319,7 +319,8 @@ end
 -- This function takes a <code><query></code> of the form
 -- <code>"name1=value1&name2=value2"</code>
 -- and returns a table containing the name-value pairs, with the name as the key
--- and the value as its associated value.
+-- and the value as its associated value. Both the name and the value are
+-- subject to URL decoding.
 -- @param query Query string.
 -- @return A table of name-value pairs following the pattern
 -- <code>table["name"]</code> = <code>value</code>.
@@ -333,9 +334,11 @@ function parse_query(query)
   query = string.gsub(query, "&gt;", ">")
 
   local function ginsert(qstr)
-    local first, last = string.find(qstr, "=")
-    if first then
-      parsed[string.sub(qstr, 0, first-1)] = string.sub(qstr, first+1)
+    local pos = qstr:find("=", 1, true)
+    if pos then
+      parsed[unescape(qstr:sub(1, pos - 1))] = unescape(qstr:sub(pos + 1))
+    else
+      parsed[unescape(qstr)] = ""
     end
   end
 
@@ -355,18 +358,19 @@ end
 ---
 -- Builds a query string from a table.
 --
--- This is the inverse of <code>parse_query</code>.
+-- This is the inverse of <code>parse_query</code>. Both the parameter name
+-- and value are subject to URL encoding.
 -- @param query A dictionary table where <code>table['name']</code> =
 -- <code>value</code>.
 -- @return A query string (like <code>"name=value2&name=value2"</code>).
 -----------------------------------------------------------------------------
 function build_query(query)
-  local qstr = ""
+  local qstr = {}
 
   for i,v in pairs(query) do
-    qstr = qstr .. i .. '=' .. v .. '&'
+    qstr[#qstr+1] = escape(i) .. '=' .. escape(v)
   end
-  return string.sub(qstr, 0, #qstr-1)
+  return table.concat(qstr, '&')
 end
 
 return _ENV;

scripts/http-form-fuzzer.nse

@@ -97,14 +97,6 @@ local function generate_safe_postdata(form)
   return postdata
 end
 
-local function generate_get_string(data)
-  local get_str = {"?"}
-  for name,value in pairs(data) do
-    get_str[#get_str+1]=url.escape(name).."="..url.escape(value).."&"
-  end
-  return table.concat(get_str)
-end
-
 -- generate a charset of characters with ascii codes from 33 to 126
 -- you can use http://www.asciitable.com/ to see which characters those actually are
 local charset = generate_charset(33,126)
@@ -156,7 +148,7 @@ local function fuzz_form(form, minlen, maxlen, host, port, path)
   if form["method"]=="post" then
     sending_function = function(data) return http.post(host, port, form_submission_path, nil, nil, data) end
   else
-    sending_function = function(data) return http.get(host, port, form_submission_path..generate_get_string(data), {no_cache=true, bypass_cache=true}) end
+    sending_function = function(data) return http.get(host, port, form_submission_path.."?"..url.build_query(data), {no_cache=true, bypass_cache=true}) end
   end
 
   for _,field in ipairs(form["fields"]) do

scripts/http-open-redirect.nse

@@ -43,6 +43,8 @@ categories = {"discovery", "intrusive"}
 
 portrule = shortport.http
 
+local redirect_canary = "http://scanme.nmap.org/"
+
 local function dbg(str,...)
   stdnse.debug2(str, ...)
 end
@@ -74,10 +76,9 @@ local function checkLocationEcho(query, destination)
   local q = url.parse_query(query);
   -- Check the values (and keys) and see if they are reflected in the location header
   for k,v in pairs(q) do
-    local s,f = string.find(destination, v)
-    if s == 1 then
+    if destination:sub(1, #v) == v then
       -- Build a new URL
-      q[k] = "http%3A%2f%2fscanme.nmap.org%2f";
+      q[k] = redirect_canary;
       return url.build_query(q)
     end
   end
@@ -123,7 +124,7 @@ action = function(host, port)
           dbg("Checking potential open redirect: %s:%s%s", host,port,url);
           local testResponse = http.get(host, port, url);
           --dbgt(testResponse)
-          if isRedirect(testResponse.status) and testResponse.header.location == "http://scanme.nmap.org/" then
+          if isRedirect(testResponse.status) and testResponse.header.location == redirect_canary then
             table.insert(results, ("%s://%s:%s%s"):format(parsed.scheme, host, port,url))
           end
         end

scripts/http-rfi-spider.nse

@@ -69,14 +69,6 @@ local function generate_safe_postdata(form)
   return postdata
 end
 
-local function generate_get_string(data)
-  local get_str = {"?"}
-  for name,value in pairs(data) do
-    get_str[#get_str+1]=url.escape(name).."="..url.escape(value).."&"
-  end
-  return table.concat(get_str)
-end
-
 -- checks each field of a form to see if it's vulnerable to rfi
 local function check_form(form, host, port, path)
   local vulnerable_fields = {}
@@ -96,7 +88,7 @@ local function check_form(form, host, port, path)
   if form["method"]=="post" then
     sending_function = function(data) return http.post(host, port, form_submission_path, nil, nil, data) end
   else
-    sending_function = function(data) return http.get(host, port, form_submission_path..generate_get_string(data), nil) end
+    sending_function = function(data) return http.get(host, port, form_submission_path.."?"..url.build_query(data), nil) end
   end
 
   for _,field in ipairs(form["fields"]) do
@@ -208,7 +200,7 @@ function action(host, port)
       end --for
     end --if
 
-    -- now try inclusion by parameters
+    -- now try inclusion by query parameters
     local injectable = {}
     -- search for injectable links (as in sql-injection.nse)
     if r.response.status and r.response.body then

scripts/http-sql-injection.nse

@@ -102,7 +102,7 @@ local function build_injection_vector(urls)
 
       for k, v in pairs(qtab) do
         old_qtab = qtab[k];
-        qtab[k] = qtab[k] ..  "'%20OR%20sqlspider"
+        qtab[k] = qtab[k] ..  "' OR sqlspider"
 
         utab.query = url.build_query(qtab)
         urlstr = url.build(utab)

scripts/http-unsafe-output-escaping.nse

@@ -78,7 +78,7 @@ local function getReflected(parsed, r)
 end
 
 local function addPayload(v)
-  return v.."ghz%3Ehzx%22zxc%27xcv"
+  return v.."ghz>hzx\"zxc'xcv"
 end
 
 local function createMinedLinks(reflected_values, all_values)