1 files changed, 170 insertions, 0 deletions
diff --git a/nselib/lpeg-utility.lua b/nselib/lpeg-utility.lua
new file mode 100644
index 0000000..47134bc
--- /dev/null
+++ b/nselib/lpeg-utility.lua
@@ -0,0 +1,170 @@
+---
+-- Utility functions for LPeg.
+--
+-- @copyright Same as Nmap--See https://nmap.org/book/man-legal.html
+-- @class module
+-- @name lpeg-utility
+
+local assert = assert
+
+local lpeg = require "lpeg"
+local stdnse = require "stdnse"
+local pairs = pairs
+local string = require "string"
+local tonumber = tonumber
+local rawset = rawset
+local lower = string.lower
+local upper = string.upper
+
+_ENV = {}
+
+local caselessP = lpeg.Cf((lpeg.P(1) / function (a) return lpeg.S(lower(a)..upper(a)) end)^1, function (a, b) return a * b end)
+---
+-- Returns a pattern which matches the literal string caselessly.
+--
+-- @param literal A literal string to match case-insensitively.
+-- @return An LPeg pattern.
+function caseless (literal)
+  return assert(caselessP:match(literal))
+end
+
+---
+-- Returns a pattern which matches the input pattern anywhere on a subject string.
+--
+-- @param patt Input pattern.
+-- @return An LPeg pattern.
+function anywhere (patt)
+  return lpeg.P {
+    patt + 1 * lpeg.V(1)
+  }
+end
+
+---
+-- Adds the current locale from lpeg.locale() to the grammar and returns the final pattern.
+--
+-- @param grammar Input grammar.
+-- @return An LPeg pattern.
+function localize (grammar)
+  return lpeg.P(lpeg.locale(grammar))
+end
+
+---
+-- Splits the input string on the input separator.
+--
+-- @param str Input string to split.
+-- @param sep Input string/pattern to separate on.
+-- @return All splits.
+function split (str, sep)
+  return lpeg.P {
+    lpeg.V "elem" * (lpeg.V "sep" * lpeg.V "elem")^0,
+    elem = lpeg.C((1 - lpeg.V "sep")^0),
+    sep = sep,
+  } :match(str)
+end
+
+---
+-- Returns a pattern which only matches at a word boundary (beginning).
+--
+-- Essentially the same as '\b' in a PCRE pattern.
+--
+-- @param patt A pattern.
+-- @return A new LPeg pattern.
+function atwordboundary (patt)
+  return _ENV.localize {
+    patt + lpeg.V "alpha"^0 * (1 - lpeg.V "alpha")^1 * lpeg.V(1)
+  }
+end
+
+---
+-- Returns a pattern which captures the contents of a quoted string.
+--
+-- This can handle embedded escaped quotes, and captures the unescaped string.
+--
+-- @param quot The quote character to use. Default: '"'
+-- @param esc The escape character to use. Cannot be the same as quot. Default: "\"
+function escaped_quote (quot, esc)
+  quot = quot or '"'
+  esc = esc or '\\'
+  return lpeg.P {
+    lpeg.Cs(lpeg.V "quot" * lpeg.Cs((lpeg.V "simple_char" + lpeg.V "noesc" + lpeg.V "unesc")^0) * lpeg.V "quot"),
+    quot = lpeg.P(quot)/"",
+    esc = lpeg.P(esc),
+    simple_char = (lpeg.P(1) - (lpeg.V "quot" + lpeg.V "esc")),
+    unesc = (lpeg.V "esc" * lpeg.C( lpeg.V "esc" + lpeg.P(quot) ))/"%1",
+    noesc = lpeg.V "esc" * lpeg.V "simple_char"
+  }
+end
+
+---
+-- Adds hooks to a grammar to print debugging information
+--
+-- Debugging LPeg grammars can be difficult. Calling this function on your
+-- grammmar will cause it to print ENTER and LEAVE statements for each rule, as
+-- well as position and subject after each successful rule match.
+--
+-- For convenience, the modified grammar is returned; a copy is not made
+-- though, and the original grammar is modified as well.
+--
+-- @param grammar The LPeg grammar to modify
+-- @param printer A printf-style formatting printer function to use.
+--                Default: stdnse.debug1
+-- @return The modified grammar.
+function debug (grammar, printer)
+  printer = printer or stdnse.debug1
+  -- Original code credit: http://lua-users.org/lists/lua-l/2009-10/msg00774.html
+  for k, p in pairs(grammar) do
+    local enter = lpeg.Cmt(lpeg.P(true), function(s, p, ...)
+      printer("ENTER %s", k) return p end)
+    local leave = lpeg.Cmt(lpeg.P(true), function(s, p, ...)
+      printer("LEAVE %s", k) return p end) * (lpeg.P("k") - lpeg.P "k");
+    grammar[k] = lpeg.Cmt(enter * p + leave, function(s, p, ...)
+      printer("---%s---", k) printer("pos: %d, [%s]", p, s:sub(1, p-1)) return p end)
+  end
+  return grammar
+end
+
+do
+  -- Cache the returned pattern
+  local getquote = escaped_quote()
+
+  -- Substitution pattern to unescape a string
+  local unescape = lpeg.P {
+    -- Substitute captures
+    lpeg.Cs((lpeg.V "simple_char" + lpeg.V "unesc")^0),
+    -- Escape char is '\'
+    esc = lpeg.P "\\",
+    -- Simple char is anything but escape char
+    simple_char = lpeg.P(1) - lpeg.V "esc",
+    -- If we hit an escape, process specials or hex code, otherwise remove the escape
+    unesc = (lpeg.V "esc" * lpeg.Cs( lpeg.V "specials" + lpeg.V "code" + lpeg.P(1) ))/"%1",
+    -- single-char escapes. These are the only ones service_scan uses
+    specials = lpeg.S "trn0" / {t="\t", r="\r", n="\n", ["0"]="\0"},
+    -- hex escape: convert to char
+    code = (lpeg.P "x" * lpeg.C(lpeg.S "0123456789abcdefABCDEF"^-2))/function(c)
+    return string.char(tonumber(c,16)) end,
+  }
+
+  --- Turn the service fingerprint reply to a probe into a binary blob
+  --@param fp the <code>port.version.service_fp</code> provided by the NSE API.
+  --@param probe the probe name to match, e.g. GetRequest, TLSSessionReq, etc.
+  --@return the raw probe response received to that probe, or nil if there was no response.
+  function get_response (fp, probe)
+    fp = string.gsub(fp, "\nSF:", "")
+    local i, e = string.find(fp, string.format("%s,%%x+,", probe))
+    if i == nil then return nil end
+    return unescape:match(getquote:match(fp, e+1))
+  end
+
+  local svfp_parser = lpeg.P ({
+      anywhere("%r(") * lpeg.Cf(lpeg.Ct("") * (lpeg.V "probematch" * lpeg.P(")%r(")^-1)^1, rawset),
+      probematch = lpeg.Cg(lpeg.C((lpeg.P(1) - ",")^1) * "," * (lpeg.R("09") + lpeg.R("AF"))^1 * "," * lpeg.Cs(getquote/function(q) return unescape:match(q) end)),
+    })
+  --- Get the service fingerprint reply to a probe into a binary blob
+  --@param fp the <code>port.version.service_fp</code> provided by the NSE API.
+  function parse_fp (fp)
+    fp = string.gsub(fp, "\nSF:", "")
+    return svfp_parser:match(fp)
+  end
+end
+
+return _ENV