Adds two new libraries, punycode and idna. Closes #958.

nselib/idna.lua

@@ -0,0 +1,544 @@
+---
+-- Library methods for handling IDNA domains.
+--
+-- Internationalized Domain Names (IDNs) follow a mechanism to process
+-- Internationalizing Domain Names in Applications (IDNA) for handling
+-- characters outside the ASCII repertoire in a standard fashion. IDNs use
+-- characters drawn from a large repertoire (Unicode), but IDNA allows the
+-- non-ASCII characters to be represented using only the ASCII characters
+-- already allowed in so-called host names today.  This backward-compatible
+-- representation is required in existing protocols like DNS, so that IDNs can be
+-- introduced with no changes to the existing infrastructure.  IDNA is
+-- only meant for processing domain names, not free text.
+--
+-- Client software, such as browsers and emailers, faces a difficult transition
+-- from the version of international domain names approved in 2003 (IDNA2003),
+-- to the revision approved in 2010 (IDNA2008). The following functions allows
+-- the developer and end user to access domains that are valid under either
+-- system but the default conversion is set to IDNA2008.
+--
+-- IDNA specification solves the problem of extending the repertoire
+-- of characters that can be used in domain names to include the Unicode
+-- repertoire (with some restrictions).
+--
+-- Applications can use IDNA to support internationalized domain names
+-- anywhere that ASCII domain names are already supported, including DNS
+-- master files and resolver interfaces. The IDNA protocol is contained
+-- completely within applications.  It is not a client-server or peer-to-peer
+-- protocol: everything is done inside the application itself.  When used with
+-- a DNS resolver library, IDNA is inserted as a "shim" between the application
+-- and the resolver library.  When used for writing names into a DNS zone, IDNA
+-- is used just before the name is committed to the zone.
+--
+-- References:
+-- * http://ietf.org/rfc/rfc3490.txt
+-- * http://tools.ietf.org/html/rfc5890
+-- * https://tools.ietf.org/html/rfc5891
+-- * http://tools.ietf.org/html/rfc5892
+-- * http://www.unicode.org/reports/tr46/
+--
+-- TODO:
+-- Add support for mapping right to left scripts for IDNA library.
+-- References:
+-- * http://tools.ietf.org/html/rfc5893
+-- * http://www.unicode.org/reports/tr9/
+-- * http://www.unicode.org/reports/tr46/#Right_to_Left_Scripts
+--
+-- @author Rewanth Cool
+-- @copyright Same as Nmap--See https://nmap.org/book/man-legal.html
+
+local stdnse = require "stdnse"
+local string = require "string"
+local math = require "math"
+local table = require "table"
+local unicode = require "unicode"
+local unittest = require "unittest"
+local punycode = require "punycode"
+local idnaMappings = require "data.idnaMappings".tbl
+
+_ENV = stdnse.module("idna", stdnse.seeall)
+
+-- Localize few functions for a tiny speed boost, since these will be
+-- used frequently.
+local floor = math.floor
+local byte = string.byte
+local char = string.char
+local find = string.find
+local match = string.match
+local reverse = string.reverse
+local sub = string.sub
+
+-- This function concatenates the strings and tables (depth = 1) in
+-- a given table.
+--
+-- @param tbl A table is given as an input which contains values as string
+-- or table (depth = 1).
+-- @return Returns table after concatinating all the values.
+local function concat_table_in_tables(tbl)
+
+  local t = {}
+  for _, v in ipairs(tbl) do
+    if type(v) == "table" then
+      for _, q in ipairs(v) do
+        table.insert(t, q)
+      end
+    else
+      table.insert(t, v)
+    end
+  end
+
+  return t
+
+end
+
+
+-- This function maps the codepoints of the input to their respective
+-- codepoints based on the latest IDNA version mapping.
+--
+-- @param decoded_tbl Table of Unicode decoded codepoints.
+-- @param useSTD3ASCIIRules Boolean value to set the mapping according to IDNA2003 rules.
+--        useSTD3ASCIIRules=true refers to IDNA2008.
+--        useSTD3ASCIIRules=false refers to IDNA2003.
+-- @param transitionalProcessing Processing option to handle deviation codepoints.
+--        transitionalProcessing=true maps deviation codepoints to the input.
+--        transitionalProcessing=false maintains original input.
+-- @param viewDisallowedCodePoints Boolean value to see the list of disallowed codepoints.
+-- @return Returns table with the list of mapped codepoints.
+function map(decoded_tbl, useSTD3ASCIIRules, transitionalProcessing, viewDisallowedCodePoints)
+
+  -- Assigns default values if not specified.
+
+  -- According to IDNA2008, transitionalProcessing=true (default).
+  if transitionalProcessing == nil then
+    transitionalProcessing = true
+  end
+
+  if useSTD3ASCIIRules == nil then
+    useSTD3ASCIIRules = true
+  end
+  if viewDisallowedCodePoints == nil then
+    viewDisallowedCodePoints = false
+  end
+
+  local disallowedCodePoints = {}
+
+  -- Mapping codepoints based on latest IDNA mapping list.
+  for index, cp in ipairs(decoded_tbl) do
+    local lookup = idnaMappings[cp]
+    if type(lookup) == "number" then
+      decoded_tbl[index] = lookup
+    -- Handles the IDNA deviated set of codepoints.
+    elseif transitionalProcessing and lookup.status == "deviation" then
+      decoded_tbl[index] = lookup[1]
+    -- Removes the IDNA ignored set of codepoints.
+    elseif lookup.status == "ignored" then
+      decoded_tbl[index] = {}
+    end
+  end
+
+  decoded_tbl = concat_table_in_tables(decoded_tbl)
+
+  --TODO:
+  -- Map bidi characters.
+  -- Right-to-left domain names.
+  -- References:
+  -- http://unicode.org/reports/tr9/
+  -- http://www.unicode.org/reports/tr46/#Right_to_Left_Scripts
+  -- http://tools.ietf.org/html/rfc5893
+
+  -- Saves the list of disallowed codepoints.
+  if viewDisallowedCodePoints then
+    for index, cp in ipairs(decoded_tbl) do
+      local lookup = idnaMappings[cp]
+      if type(lookup) == "table" then
+        if lookup.status == "disallowed" then
+          table.insert(disallowedCodePoints, cp)
+        end
+      end
+
+      -- If useSTD3ASCIIRules=true, both the disallowed_STD3_valid and
+      -- disallowed_STD3_mapped are considered as disallowed codepoints.
+      -- To use this part of code, add disallowed_STD3_mapped and disallowed_STD3_valid
+      -- codepoints to idnaMappings.lua. For now, we ignore these because idnaMappings.lua
+      -- is set to support only for the latest version of IDNA.
+      if useSTD3ASCIIRules then
+        if type(lookup) == "table" then
+          if lookup.status == "disallowed_STD3_valid" or lookup.status == "disallowed_STD3_mapped" then
+            table.insert(disallowedCodePoints, cp)
+          end
+        end
+      end
+    end
+  end
+
+  decoded_tbl = concat_table_in_tables(decoded_tbl)
+
+  -- If useSTD3ASCIIRules=false, then disallowed_STD3_mapped values are considered
+  -- as mapped codepoints and are mapped with the input.
+  -- To use this part of code, add disallowed_STD3_mapped and disallowed_STD3_valid
+  -- codepoints to idnaMappings.lua. For now, we ignore these because idnaMappings.lua
+  -- is set to support only for the latest version of IDNA.
+  if not useSTD3ASCIIRules then
+    for index, cp in ipairs(decoded_tbl) do
+      local lookup = idnaMappings[cp]
+      if type(lookup) == "table" then
+        if lookup.status == "disallowed_STD3_mapped" then
+          decoded_tbl[index] = lookup[1]
+        end
+      end
+    end
+  end
+
+  decoded_tbl = concat_table_in_tables(decoded_tbl)
+
+  return decoded_tbl, disallowedCodePoints
+end
+
+
+-- Validate the input based on IDNA codepoints validation rules.
+--
+-- @param tableOfTables Table of codepoints of the splitted input.
+-- @param checkHyphens Boolean flag checks for 0x002D in unusual places.
+function validate(tableOfTables, checkHyphens)
+
+  if checkHyphens == nil then
+    checkHyphens = true
+  end
+
+  -- Validates the list of input codepoints.
+  for _, tbl in ipairs(tableOfTables) do
+
+    if checkHyphens then
+
+      -- Checks the 3rd and 4th position of input.
+      if (tbl[3] and tbl[3] == 0x002D) or (tbl[4] and tbl[4] == 0x002D) then
+        return false
+      end
+
+      -- Checks for starting and ending of input.
+      if tbl[1] == 0x002D or tbl[#tbl] == 0x002D then
+        return false
+      end
+
+    end
+
+    for _, v in ipairs(tbl) do
+      if v == 0x002E then
+        return false
+      end
+    end
+
+    -- TODO:
+    -- 1. Add validation for checkBidi, checkJoiners (if required).
+    -- 2. The label must not begin with a combining mark, that is: General_Category=Mark.
+  end
+
+  return true
+
+end
+
+-- This function converts the input codepoints into ASCII text based on IDNA rules.
+--
+-- @param codepoints Table of codepoints of decoded input.
+-- @param tbl Table of optional params.
+-- @param transitionalProcessing Boolean value. Default: true.
+-- @param checkHyphens Boolean flag for checking hyphens presence in input.
+--        Default: true.
+-- @param checkBidi Boolean flag to represent if the input is of Bidi type.
+--        Default: false.
+-- @param checkJoiners Boolean flag to check for ContextJ rules in input.
+--        Default: false.
+-- @param useSTD3ASCIIRules Boolean value to represent ASCII rules. Default: true.
+-- @param delimiter codepoint of the character to be used as delimiter.
+-- @param encoder Encoder function to convert a Unicode codepoint into a
+-- string of bytes.
+-- @param An decoder function to decode the input string
+-- into an array of code points.
+-- @return Returns the IDNA ASCII format of the input.
+-- @return Throws nil, if there is any error in conversion.
+function toASCII(codepoints, transitionalProcessing, checkHyphens, checkBidi, checkJoiners, useSTD3ASCIIRules, delimiter, encoder, decoder)
+
+  -- Assigns default values if not specified.
+  if transitionalProcessing == nil then
+    transitionalProcessing = true
+  end
+  if checkHyphens == nil then
+    checkHyphens = true
+  end
+
+  -- Bidi refers to right-to-left scripts.
+  -- Labels must satisfy all six of the numbered conditions in RFC 5893, Section 2.
+  -- to use checkBidi functionality.
+  if checkBidi == nil then
+    checkBidi = false
+  end
+
+  -- Labels must satisify the ContextJ rules to use checkJoiners functionality.
+  if checkJoiners == nil then
+    checkJoiners = false
+  end
+
+  if useSTD3ASCIIRules == nil then
+    useSTD3ASCIIRules = true
+  end
+
+  delimiter = delimiter or 0x002E
+  encoder = encoder or unicode.utf8_enc
+  decoder = decoder or unicode.utf8_dec
+
+  local inputString = unicode.encode(codepoints, encoder)
+
+  local decoded_tbl, disallowedCodePoints = map(codepoints, useSTD3ASCIIRules, transitionalProcessing)
+
+  if decoded_tbl == nil then
+    return nil
+  end
+
+  -- Prints the list of disallowed values in the given input.
+  if #disallowedCodePoints > 0 then
+    stdnse.debug(table.concat(disallowedCodePoints, ", "))
+  end
+
+  -- Breaks the codepoints into multiple tables using delimiter.
+  decoded_tbl = punycode.breakInput(decoded_tbl, delimiter)
+
+  if decoded_tbl == nil then
+    return nil
+  end
+
+  -- Validates the codepoints and if any invalid codepoint found, returns nil.
+  if not validate(decoded_tbl, checkHyphens) then
+    return nil
+  end
+
+  local stringLabels = {}
+
+  -- Convert the codepoints into Unicode strings before passing them to mapLabels function.
+  for _, label in ipairs(decoded_tbl) do
+    table.insert(stringLabels, unicode.encode(label, encoder))
+  end
+
+  return punycode.mapLabels(stringLabels, punycode.encode_label, decoder, unicode.encode({0x002E}, encoder))
+
+end
+
+-- This function converts the input into Unicode codepoitns based on IDNA rules.
+--
+-- @param codepoints Table of codepoints of decoded input.
+-- @param transitionalProcessing Boolean value. Default: true.
+-- @param checkHyphens Boolean flag for checking hyphens presence in input.
+--        Default: true.
+-- @param checkBidi Boolean flag to represent if the input is of Bidi type.
+--        Default: false.
+-- @param checkJoiners Boolean flag to check for ContextJ rules in input.
+--        Default: false.
+-- @param useSTD3ASCIIRules Boolean value to represent ASCII rules. Default: true.
+-- @param delimiter, codepoint of the character to be used as delimiter.
+-- @param encoder Encoder function to convert a Unicode codepoint into a
+-- string of bytes.
+-- @param An decoder function to decode the input string
+-- into an array of code points.
+-- @return Returns the Unicode format of the input based on IDNA rules.
+-- @return Throws nil, if there is any error in conversion.
+function toUnicode(decoded_tbl, transitionalProcessing, checkHyphens, checkBidi, checkJoiners, useSTD3ASCIIRules, delimiter, encoder, decoder)
+
+  -- Assigns default values if not specified.
+  if transitionalProcessing == nil then
+    transitionalProcessing = true
+  end
+  if checkHyphens == nil then
+    checkHyphens = true
+  end
+  if checkBidi == nil then
+    checkBidi = false
+  end
+  if checkJoiners == nil then
+    checkJoiners = false
+  end
+  if useSTD3ASCIIRules == nil then
+    useSTD3ASCIIRules = true
+  end
+
+  delimiter = delimiter or 0x002E
+  encoder = encoder or unicode.utf8_enc
+  decoder = decoder or unicode.utf8_dec
+
+  -- Breaks the codepoints into multiple tables using delimiter.
+  decoded_tbl = punycode.breakInput(decoded_tbl, delimiter)
+  if decoded_tbl == nil then
+    return nil
+  end
+
+  local stringLabels = {}
+
+  -- Format the codepoints into strings before passing to punycode.mapLabels
+  for _, label in ipairs(decoded_tbl) do
+    table.insert(stringLabels, unicode.encode(label, encoder))
+  end
+
+  return punycode.mapLabels(stringLabels, punycode.decode_label, encoder, unicode.encode({0x002E}, encoder))
+
+end
+
+if not unittest.testing() then
+  return _ENV
+end
+
+-- These are the used for two way testing (both encoding and decoding).
+local encodingAndDecodingTestCases = {
+  {
+    "\xce\xb1\xcf\x80\xcf\x80\xce\xbb\xce\xb5.\xce\xba\xce\xbf\xce\xbc",
+    "xn--mxairta.xn--vxaei"
+  },
+  {
+    "a\xe0\xa5\x8db",
+    "xn--ab-fsf"
+  },
+  {
+    "\xd9\x86\xd8\xa7\xd9\x85\xd9\x87\xd8\xa7\xdb\x8c.com",
+    "xn--mgba3gch31f.com"
+  },
+  {
+    "\xe0\xb7\x81\xe0\xb7\x8a\xe0\xb6\xbb\xe0\xb7\x93.com",
+    "xn--10cl1a0b.com"
+  },
+  {
+    "\xd0\xbf\xd1\x80\xd0\xb0\xd0\xb2\xd0\xb8\xd1\x82\xd0\xb5\xd0\xbb\xd1\x8c\xd1\x81\xd1\x82\xd0\xb2\xd0\xbe.\xd1\x80\xd1\x84",
+    "xn--80aealotwbjpid2k.xn--p1ai"
+  },
+  {
+    "\xe0\xa4\x95\xe0\xa4\xbe\xe0\xa4\xb6\xe0\xa5\x80\xe0\xa4\xaa\xe0\xa5\x81\xe0\xa4\xb0.\xe0\xa4\xad\xe0\xa4\xbe\xe0\xa4\xb0\xe0\xa4\xa4",
+    "xn--11b6bsw3bni.xn--h2brj9c"
+  },
+  {
+    "rewanthcool.com",
+    "rewanthcool.com"
+  },
+  {
+    "\xe3\xaf\x99\xe3\xaf\x9c\xe3\xaf\x99\xe3\xaf\x9f.com",
+    "xn--domain.com"
+  }
+}
+
+-- These test cases are used for only converting them into ASCII text.
+local toASCIITestCases = {
+  {
+    "ma\xc3\xb1ana.com",
+    "xn--maana-pta.com"
+  },
+  {
+    "RewanthCool.com",
+    "rewanthcool.com"
+  },
+  {
+    "\xc3\xb6bb.at",
+    "xn--bb-eka.at"
+  },
+  {
+    "\xe3\x83\x89\xe3\x83\xa1\xe3\x82\xa4\xe3\x83\xb3.\xe3\x83\x86\xe3\x82\xb9\xe3\x83\x88",
+    "xn--eckwd4c7c.xn--zckzah"
+  },
+  {
+    "\xd0\xb4\xd0\xbe\xd0\xbc\xd0\xb5\xd0\xbd\xd0\xb0.\xd0\xb8\xd1\x81\xd0\xbf\xd1\x8b\xd1\x82\xd0\xb0\xd0\xbd\xd0\xb8\xd0\xb5",
+    "xn--80ahd1agd.xn--80akhbyknj4f"
+  },
+  {
+    "\xe6\xb5\x8b\xe8\xaf\x95",
+    "xn--0zwm56d"
+  },
+  {
+    "k\xc3\xb6nigsg\xc3\xa4\xc3\x9fchen",
+    "xn--knigsgsschen-lcb0w"
+  },
+  {
+    "fa\xc3\x9f.de",
+    "fass.de"
+  },
+  {
+    "\xce\xb2\xcf\x8c\xce\xbb\xce\xbf\xcf\x82.com",
+    "xn--nxasmq6b.com"
+  },
+  {
+    "mycharity\xe3\x80\x82org",
+    "mycharity.org"
+  },
+  {
+    "K\xc3\xb6nigsg\xc3\xa4\xc3\x9fchen",
+    "xn--knigsgsschen-lcb0w"
+  },
+  {
+    "B\xc3\xbccher.de",
+    "xn--bcher-kva.de"
+  },
+  {
+    "xn--ma\xc3\xb1ana.com",
+    nil
+  }
+}
+
+-- These test cases are used for only converting them into ASCII text.
+-- The last two values in a table are outputs for different cases.
+--
+-- Format:
+-- {
+--  input unicode string,
+--  transitional processed output, --transitional=true
+--  non-transitional processed output --transitional=false
+-- }
+local multipleProcessingTestCases = {
+  {
+    "a\xe0\xa5\x8d\xe2\x80\x8cb",
+    "xn--ab-fsf",
+    "xn--ab-fsf604u"
+  },
+  {
+    "A\xe0\xa5\x8d\xe2\x80\x8cb",
+    "xn--ab-fsf",
+    "xn--ab-fsf604u"
+  },
+  {
+    "A\xe0\xa5\x8d\xe2\x80\x8Cb",
+    "xn--ab-fsf",
+    "xn--ab-fsf604u"
+  },
+  {
+    "\xd9\x86\xd8\xa7\xd9\x85\xd9\x87\xe2\x80\x8c\xd8\xa7\xdb\x8c",
+    "xn--mgba3gch31f",
+    "xn--mgba3gch31f060k"
+  },
+  {
+    "\xd9\x86\xd8\xa7\xd9\x85\xd9\x87\xe2\x80\x8c\xd8\xa7\xdb\x8c.com",
+    "xn--mgba3gch31f.com",
+    "xn--mgba3gch31f060k.com"
+  },
+  {
+    "\xc3\x9f\xe0\xa7\x81\xe1\xb7\xad\xe3\x80\x82\xd8\xa085",
+    "xn--ss-e2f077r.xn--85-psd",
+    "xn--zca266bwrr.xn--85-psd"
+  },
+  {
+    "\xc3\x9f\xe0\xa7\x81\xe1\xb7\xad\xe3\x80\x82\xd8\xa08\xe2\x82\x85",
+    "xn--ss-e2f077r.xn--85-psd",
+    "xn--zca266bwrr.xn--85-psd"
+  }
+}
+
+test_suite = unittest.TestSuite:new()
+
+for _, v in ipairs(toASCIITestCases) do
+  test_suite:add_test(unittest.equal(toASCII(unicode.decode(v[1], unicode.utf8_dec)), v[2]))
+end
+
+for _, v in ipairs(encodingAndDecodingTestCases) do
+  test_suite:add_test(unittest.equal(toASCII(unicode.decode(v[1], unicode.utf8_dec)), v[2]))
+  test_suite:add_test(unittest.equal(toUnicode(unicode.decode(v[2], unicode.utf8_dec)), v[1]))
+end
+
+for _, v in ipairs(multipleProcessingTestCases) do
+  -- Performs transitional conversion.
+  test_suite:add_test(unittest.equal(toASCII(unicode.decode(v[1], unicode.utf8_dec)), v[2]))
+  -- Performs non-transitional conversion.
+  test_suite:add_test(unittest.equal(toASCII(unicode.decode(v[1], unicode.utf8_dec), false), v[3]))
+end
+
+return _ENV