---
-- A smallish implementation of the Couchbase Membase TAP protocol
-- Based on the scarce documentation from the Couchbase Wiki:
-- x http://www.couchbase.org/wiki/display/membase/SASL+Authentication+Example
--
-- @author "Patrik Karlsson <patrik@cqure.net>"
--
local bin = require "bin"
local match = require "match"
local nmap = require "nmap"
local sasl = require "sasl"
local stdnse = require "stdnse"
local table = require "table"
_ENV = stdnse.module("membase", stdnse.seeall)
-- A minimalistic implementation of the Couchbase Membase TAP protocol
TAP = {
-- Operations
Op = {
LIST_SASL_MECHS = 0x20,
AUTHENTICATE = 0x21,
},
-- Requests
Request = {
-- Header breakdown
-- Field (offset) (value)
-- Magic (0): 0x80 (PROTOCOL_BINARY_REQ)
-- Opcode (1): 0x00
-- Key length (2-3): 0x0000 (0)
-- Extra length (4): 0x00
-- Data type (5): 0x00
-- vbucket (6-7): 0x0000 (0)
-- Total body (8-11): 0x00000000 (0)
-- Opaque (12-15): 0x00000000 (0)
-- CAS (16-23): 0x0000000000000000 (0)
Header = {
-- Creates a new instance of Header
-- @param opcode number containing the operation
-- @return o new instance of Header
new = function(self, opcode)
local o = {
magic = 0x80,
opcode = tonumber(opcode),
keylen = 0x0000,
extlen = 0x00,
data_type = 0x00,
vbucket = 0x0000,
total_body = 0x00000000,
opaque = 0x00000000,
CAS = 0x0000000000000000,
}
setmetatable(o, self)
self.__index = self
return o
end,
-- Converts the header to string
-- @return string containing the Header as string
__tostring = function(self)
return bin.pack(">CCSCCSIIL", self.magic, self.opcode, self.keylen,
self.extlen, self.data_type, self.vbucket, self.total_body,
self.opaque, self.CAS)
end,
},
-- List SASL authentication mechanism
SASLList = {
-- Creates a new instance of the request
-- @return o instance of request
new = function(self)
local o = {
-- 0x20 SASL List Mechs
header = TAP.Request.Header:new(TAP.Op.LIST_SASL_MECHS)
}
setmetatable(o, self)
self.__index = self
return o
end,
-- Converts the request to string
-- @return string containing the request as string
__tostring = function(self)
return tostring(self.header)
end,
},
-- Authenticates using SASL
Authenticate = {
-- Creates a new instance of the request
-- @param username string containing the username
-- @param password string containing the password
-- @param mech string containing the SASL mechanism, currently suppored:
-- PLAIN - plain-text authentication
-- @return o instance of request
new = function(self, username, password, mech)
local o = {
-- 0x20 SASL List Mechs
header = TAP.Request.Header:new(TAP.Op.AUTHENTICATE),
username = username,
password = password,
mech = mech,
}
setmetatable(o, self)
self.__index = self
return o
end,
-- Converts the request to string
-- @return string containing the request as string
__tostring = function(self)
if ( self.mech == "PLAIN" ) then
local mech_params = { self.username, self.password }
local auth_data = sasl.Helper:new(self.mech):encode(table.unpack(mech_params))
self.header.keylen = #self.mech
self.header.total_body = #auth_data + #self.mech
return tostring(self.header) .. self.mech .. auth_data
end
end,
}
},
-- Responses
Response = {
-- The response header
-- Header breakdown
-- Field (offset) (value)
-- Magic (0): 0x81 (PROTOCOL_BINARY_RES)
-- Opcode (1): 0x00
-- Key length (2-3): 0x0000 (0)
-- Extra length (4): 0x00
-- Data type (5): 0x00
-- Status (6-7): 0x0000 (SUCCESS)
-- Total body (8-11): 0x00000005 (5)
-- Opaque (12-15): 0x00000000 (0)
-- CAS (16-23): 0x0000000000000000 (0)
Header = {
-- Creates a new instance of Header
-- @param data string containing the raw data
-- @return o new instance of Header
new = function(self, data)
local o = {
data = data
}
setmetatable(o, self)
self.__index = self
if ( o:parse() ) then
return o
end
end,
-- Parse the raw header and populates the class members
-- @return status true on success, false on failure
parse = function(self)
if ( 24 > #self.data ) then
stdnse.print_debug("membase: Header packet too short (%d bytes)", #self.data)
return false, "Packet to short"
end
local pos
pos, self.magic, self.opcode, self.keylen, self.extlen,
self.data_type, self.status, self.total_body, self.opaque,
self.CAS = bin.unpack(">CCSCCSIIL", self.data)
return true
end
},
-- Decoders
Decoder = {
-- TAP.Op.LIST_SASL_MECHS
[0x20] = {
-- Creates a new instance of the decoder
-- @param data string containing the raw response
-- @return o instance if successfully parsed, nil on failure
-- the member variable <code>mechs</code> contains the
-- supported authentication mechanisms.
new = function(self, data)
local o = { data = data }
setmetatable(o, self)
self.__index = self
if ( o:parse() ) then
return o
end
end,
-- Parses the raw response
-- @return true on success
parse = function(self)
self.mechs = self.data
return true
end
},
-- Login response
[0x21] = {
-- Creates a new instance of the decoder
-- @param data string containing the raw response
-- @return o instance if successfully parsed, nil on failure
-- the member variable <code>status</code> contains the
-- servers authentication response.
new = function(self, data)
local o = { data = data }
setmetatable(o, self)
self.__index = self
if ( o:parse() ) then
return o
end
end,
-- Parses the raw response
-- @return true on success
parse = function(self)
self.status = self.data
return true
end
}
}
},
}
-- The Helper class is the main script interface
Helper = {
-- Creates a new instance of the helper
-- @param host table as received by the action method
-- @param port table as received by the action method
-- @param options table including options to the helper, currently:
-- <code>timeout</code> - socket timeout in milliseconds
new = function(self, host, port, options)
local o = {
host = host,
port = port,
mech = stdnse.get_script_args("membase.authmech"),
options = options or {}
}
setmetatable(o, self)
self.__index = self
return o
end,
-- Connects the socket to the server
-- @return true on success, false on failure
connect = function(self)
self.socket = nmap.new_socket()
self.socket:set_timeout(self.options.timeout or 10000)
return self.socket:connect(self.host, self.port)
end,
-- Closes the socket
close = function(self)
return self.socket:close()
end,
-- Sends a request to the server, receives and parses the response
-- @param req a Request instance
-- @return status true on success, false on failure
-- @return response instance of Response
exch = function(self, req)
local status, err = self.socket:send(tostring(req))
if ( not(status) ) then
return false, "Failed to send data"
end
local data
status, data = self.socket:receive_buf(match.numbytes(24), true)
if ( not(status) ) then
return false, "Failed to receive data"
end
local header = TAP.Response.Header:new(data)
if ( header.opcode ~= req.header.opcode ) then
stdnse.print_debug("WARNING: Received invalid op code, request contained (%d), response contained (%d)", req.header.opcode, header.opcode)
end
if ( not(TAP.Response.Decoder[tonumber(header.opcode)]) ) then
return false, ("No response handler for opcode: %d"):format(header.opcode)
end
local status, data = self.socket:receive_buf(match.numbytes(header.total_body), true)
if ( not(status) ) then
return false, "Failed to receive data"
end
local response = TAP.Response.Decoder[tonumber(header.opcode)]:new(data)
if ( not(response) ) then
return false, "Failed to parse response from server"
end
return true, response
end,
-- Gets list of supported SASL authentication mechanisms
getSASLMechList = function(self)
return self:exch(TAP.Request.SASLList:new())
end,
-- Logins to the server
-- @param username string containing the username
-- @param password string containing the password
-- @param mech string containing the SASL mechanism to use
-- @return status true on success, false on failure
-- @return respons string containing "Auth failure" on failure
login = function(self, username, password, mech)
mech = mech or self.mech or "PLAIN"
local status, response = self:exch(TAP.Request.Authenticate:new(username, password, mech))
if ( not(status) ) then
return false, "Auth failure"
end
if ( response.status == "Auth failure" ) then
return false, response.status
end
return true, response.status
end,
}
return _ENV;
@KyuuKazami