Mongodb Nmap NSE script fails

[26ayushagarwal]

Hello,

While running mongodb scripts fail with error message.

Nmap Version : 7.80

/usr/bin/../share/nmap/nselib/mongodb.lua:379: bad argument #2 to 'pack' (unsigned overflow)
stack traceback:
[C]: in function 'string.pack'
/usr/bin/../share/nmap/nselib/mongodb.lua:379: in method 'addUnsignedInt32'
/usr/bin/../share/nmap/nselib/mongodb.lua:421: in function </usr/bin/../share/nmap/nselib/mongodb.lua:416>
(...tail calls...)
/usr/bin/../share/nmap/scripts/mongodb-brute.nse:77: in upvalue 'needsAuth'
/usr/bin/../share/nmap/scripts/mongodb-brute.nse:97: in function </usr/bin/../share/nmap/scripts/mongodb-brute.nse:95>
(...tail calls...)

[nnposter]

Thank you for reporting the issue. Could you please validate that the following minimalist patch rectifies it?

--- nselib/mongodb.lua.orig     2019-02-02 18:40:29.517567300 -0700
+++ nselib/mongodb.lua  2019-11-11 18:37:16.574910400 -0700
@@ -127,7 +127,7 @@
   end
   dbg("Packet length is %d",length)
   --Final pack
-  return true, string.pack("<I4z", length, elements)
+  return true, string.pack("<I4", length) .. elements .. "\0"
 end

 -- Reads a null-terminated string. If length is supplied, it is just cut
@@ -418,7 +418,7 @@
   packet:addUnsignedInt32(0); -- options
   packet:addString(collectionName);
   packet:addUnsignedInt32(0) -- number to skip
-  packet:addUnsignedInt32(-1) -- number to return : no limit
+  packet:addUnsignedInt32(0xFFFFFFFF) -- number to return : no limit
   local status, error = packet:addBSON(query)

   if not status then

If yes, I would then ask you to test another patch, which is slightly larger but cleaner.