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--- -- PostgreSQL library supporting both version 2 and version 3 of the protocol. -- The library currently contains the bare minimum to perform authentication. -- Authentication is supported with or without SSL enabled and using the -- plain-text or MD5 authentication mechanisms. -- -- The PGSQL protocol is explained in detail in the following references. -- * http://developer.postgresql.org/pgdocs/postgres/protocol.html -- * http://developer.postgresql.org/pgdocs/postgres/protocol-flow.html -- * http://developer.postgresql.org/pgdocs/postgres/protocol-message-formats.html -- -- @copyright Same as Nmap--See http://nmap.org/book/man-legal.html -- @author "Patrik Karlsson <patrik@cqure.net>" local bin = require "bin" local nmap = require "nmap" local stdnse = require "stdnse" local openssl = stdnse.silent_require "openssl" local string = require "string" local table = require "table" _ENV = stdnse.module("pgsql", stdnse.seeall) -- Version 0.3 -- Created 02/05/2010 - v0.1 - created by Patrik Karlsson <patrik@cqure.net> -- Revised 02/20/2010 - v0.2 - added detectVersion to automaticaly detect and return -- the correct version class -- Revised 03/04/2010 - v0.3 - added support for trust authentication method --- Supported pgsql message types MessageType = { Error = 0x45, BackendKeyData = 0x4b, AuthRequest=0x52, ParameterStatus = 0x53, ReadyForQuery = 0x5a, PasswordMessage = 0x70, } --- Supported authentication types AuthenticationType = { Success = 0x00, Plain = 0x03, MD5 = 0x05 } -- Version 2 of the protocol v2 = { --- Pad a string with zeroes -- -- @param str string containing the string to be padded -- @param len number containing the wanted length -- @return string containing the padded string value zeroPad = function(str, len) local padding = len - str:len() if ( padding < 0 ) then return str end for i=1,padding do str = str .. string.char(0x00) end return str end, messageDecoder = { --- Decodes an Auth Request packet -- -- @param data string containing raw data recieved from socket -- @param len number containing the length as retrieved from the header -- @param pos number containing the offset into the data buffer -- @return pos number containing the offset after decoding, -1 on error -- @return response table containing zero or more of the following <code>salt</code> and <code>success</code> -- error string containing error message if pos is -1 [MessageType.AuthRequest] = function( data, len, pos ) local _, authtype local response = {} pos, authtype = bin.unpack(">I", data, pos) if ( authtype == AuthenticationType.MD5 ) then if ( len - pos + 1 ) < 3 then return -1, "ERROR: Malformed AuthRequest received" end pos, response.salt = bin.unpack("A4", data, pos) elseif ( authtype == AuthenticationType.Plain ) then --do nothing elseif ( authtype == 0 ) then response.success = true else stdnse.print_debug( ("unknown auth type: %d"):format(authtype) ) end response.authtype = authtype return pos, response end, --- Decodes an Error packet -- -- @param data string containing raw data recieved from socket -- @param len number containing the length as retrieved from the header -- @param pos number containing the offset into the data buffer -- @return pos number containing the offset after decoding -- @return response table containing zero or more of the following <code>error.severity</code>, -- <code>error.code</code>, <code>error.message</code>, <code>error.file</code>, -- <code>error.line</code> and <code>error.routine</code> [MessageType.Error] = function( data, len, pos ) local tmp = data:sub(pos, pos + len - 4) local response = {} local pos_end = pos + len response.error = {} pos, response.error.message = bin.unpack("z", data, pos) return pos, response end, }, --- Process the server response -- -- @param data string containing the server response -- @param pos number containing the offset into the data buffer processResponse = function(data, pos) local ptype, len, status, response local pos = pos or 1 pos, ptype = bin.unpack("C", data, pos) len = data:len() - 1 if v2.messageDecoder[ptype] then pos, response = v2.messageDecoder[ptype](data, len, pos) if pos ~= -1 then response.type = ptype return pos, response end else stdnse.print_debug( ("Missing decoder for %d"):format(ptype) ) return -1, ("Missing decoder for %d"):format(ptype) end return -1, "Decoding failed" end, --- Reads a packet and handles additional socket reads to retrieve remaining data -- -- @param socket socket already connected to the pgsql server -- @param data string containing any data already retrieved from the socket -- @param pos number containing the offset into the data buffer -- @return data string containing the initial and any additional data readPacket=function(socket, data, pos) local pos = pos or 1 local data = data or "" local status = true local tmp = "" local ptype, len local catch = function() socket:close() stdnse.print_debug("processResponse(): failed") end local try = nmap.new_try(catch) if ( data == nil or data:len() == 0 ) then data = try(socket:receive()) end return data end, --- Sends a startup message to the server containing the username and database to connect to -- -- @param socket socket already connected to the pgsql server -- @param user string containing the name of the user -- @param database string containing the name of the database -- @return status true on success, false on failure -- @return table containing a processed response from <code>processResponse</code> -- string containing error message if status is false sendStartup=function(socket, user, database) local data, response, status, pos local proto_ver, ptype, _, tmp local tty, unused, args = "", "", "" proto_ver = 0x0020000 user = v2.zeroPad(user, 32) database = v2.zeroPad(database, 64) data = bin.pack(">I>IAAAAA", 296, proto_ver, database, user, v2.zeroPad(args, 64), v2.zeroPad(unused, 64), v2.zeroPad(tty,64) ) socket:send( data ) -- attempt to verify version status, data = socket:receive_bytes( 1 ) if ( not(status) ) then return false, "sendStartup failed" end data = v2.readPacket(socket, data ) pos, response = v2.processResponse( data ) if ( pos < 0 or response.type == MessageType.Error) then return false, response.error.message or "unknown error" end return true, response end, --- Attempts to authenticate to the pgsql server -- Supports plain-text and MD5 authentication -- -- @param socket socket already connected to the pgsql server -- @param params table containing any additional parameters <code>authtype</code>, <code>version</code> -- @param username string containing the username to use for authentication -- @param password string containing the password to use for authentication -- @param salt string containing the crypthographic salt value -- @return status true on success, false on failure -- @return result table containing parameter status information, -- result string containing an error message if login fails loginRequest = function ( socket, params, username, password, salt ) local catch = function() socket:close() stdnse.print_debug("loginRequest(): failed") end local try = nmap.new_try(catch) local response = {} local status, data, len, pos, tmp if ( params.authtype == AuthenticationType.MD5 ) then local hash = createMD5LoginHash(username,password,salt) data = bin.pack( ">Iz", 40, hash) try( socket:send( data ) ) elseif ( params.authtype == AuthenticationType.Plain ) then local data data = bin.pack(">Iz", password:len() + 4, password) try( socket:send( data ) ) elseif ( params.authtype == AuthenticationType.Success ) then return true, nil end data, response.params = "", {} data = v2.readPacket(socket, data, 1) pos, tmp = v2.processResponse(data, 1) -- this should contain the AuthRequest packet if tmp.type ~= MessageType.AuthRequest then return false, "Expected AuthRequest got something else" end if not tmp.success then return false, "Login failure" end return true, response end, } -- Version 3 of the protocol v3 = { messageDecoder = { --- Decodes an Auth Request packet -- -- @param data string containing raw data recieved from socket -- @param len number containing the length as retrieved from the header -- @param pos number containing the offset into the data buffer -- @return pos number containing the offset after decoding, -1 on error -- @return response table containing zero or more of the following <code>salt</code> and <code>success</code> -- error string containing error message if pos is -1 [MessageType.AuthRequest] = function( data, len, pos ) local _, authtype local response = {} pos, authtype = bin.unpack(">I", data, pos) if ( authtype == AuthenticationType.MD5 ) then if ( len - pos + 1 ) < 3 then return -1, "ERROR: Malformed AuthRequest received" end pos, response.salt = bin.unpack("A4", data, pos) elseif ( authtype == AuthenticationType.Plain ) then --do nothing elseif ( authtype == 0 ) then response.success = true else stdnse.print_debug( "unknown auth type: %d", authtype ) end response.authtype = authtype return pos, response end, --- Decodes an ParameterStatus packet -- -- @param data string containing raw data recieved from socket -- @param len number containing the length as retrieved from the header -- @param pos number containing the offset into the data buffer -- @return pos number containing the offset after decoding -- @return response table containing zero or more of the following <code>key</code> and <code>value</code> [MessageType.ParameterStatus] = function( data, len, pos ) local tmp, _ local response = {} tmp = data:sub(pos, pos + len - 4) _, response.key, response.value = bin.unpack("zz", tmp) return pos + len - 4, response end, --- Decodes an Error packet -- -- @param data string containing raw data recieved from socket -- @param len number containing the length as retrieved from the header -- @param pos number containing the offset into the data buffer -- @return pos number containing the offset after decoding -- @return response table containing zero or more of the following <code>error.severity</code>, -- <code>error.code</code>, <code>error.message</code>, <code>error.file</code>, -- <code>error.line</code> and <code>error.routine</code> [MessageType.Error] = function( data, len, pos ) local tmp = data:sub(pos, pos + len - 4) local _, value, prefix local response = {} local pos_end = pos + len response.error = {} while ( pos < pos_end - 5 ) do pos, prefix, value = bin.unpack("Az", data, pos) if prefix == 'S' then response.error.severity = value elseif prefix == 'C' then response.error.code = value elseif prefix == 'M' then response.error.message = value elseif prefix == 'F' then response.error.file = value elseif prefix == 'L' then response.error.line = value elseif prefix == 'R' then response.error.routine = value end end return pos, response end, --- Decodes the BackendKeyData packet -- -- @param data string containing raw data recieved from socket -- @param len number containing the length as retrieved from the header -- @param pos number containing the offset into the data buffer -- @return pos number containing the offset after decoding, -1 on error -- @return response table containing zero or more of the following <code>pid</code> and <code>key</code> -- error string containing error message if pos is -1 [MessageType.BackendKeyData] = function( data, len, pos ) local response = {} if len ~= 12 then return -1, "ERROR: Invalid BackendKeyData packet" end pos, response.pid, response.key = bin.unpack(">I>I", data, pos) return pos, response end, --- Decodes an ReadyForQuery packet -- -- @param data string containing raw data recieved from socket -- @param len number containing the length as retrieved from the header -- @param pos number containing the offset into the data buffer -- @return pos number containing the offset after decoding, -1 on error -- @return response table containing zero or more of the following <code>status</code> -- error string containing error message if pos is -1 [MessageType.ReadyForQuery] = function( data, len, pos ) local response = {} if len ~= 5 then return -1, "ERROR: Invalid ReadyForQuery packet" end pos, response.status = bin.unpack("C", data, pos ) return pos, response end, }, --- Reads a packet and handles additional socket reads to retrieve remaining data -- -- @param socket socket already connected to the pgsql server -- @param data string containing any data already retrieved from the socket -- @param pos number containing the offset into the data buffer -- @return data string containing the initial and any additional data readPacket = function(socket, data, pos) local pos = pos or 1 local data = data or "" local status = true local tmp = "" local ptype, len local header local catch = function() socket:close() stdnse.print_debug("processResponse(): failed") end local try = nmap.new_try(catch) if ( data:len() - pos < 5 ) then status, tmp = socket:receive_bytes( 5 - ( data:len() - pos ) ) end if not status then return nil, "Failed to read packet" end if tmp:len() ~= 0 then data = data .. tmp end pos, header = v3.decodeHeader(data,pos) while data:len() < header.len do data = data .. try(socket:receive_bytes( ( header.len + 1 ) - data:len() )) end return data end, --- Decodes the postgres header -- -- @param data string containing the server response -- @param pos number containing the offset into the data buffer -- @return pos number containing the offset after decoding -- @return header table containing <code>type</code> and <code>len</code> decodeHeader = function(data, pos) local ptype, len pos, ptype, len = bin.unpack("C>I", data, pos) return pos, { ['type'] = ptype, ['len'] = len } end, --- Process the server response -- -- @param data string containing the server response -- @param pos number containing the offset into the data buffer -- @return pos number containing offset after decoding -- @return response string containing decoded data -- error message if pos is -1 processResponse = function(data, pos) local ptype, len, status, response local pos = pos or 1 local header pos, header = v3.decodeHeader( data, pos ) if v3.messageDecoder[header.type] then pos, response = v3.messageDecoder[header.type](data, header.len, pos) if pos ~= -1 then response.type = header.type return pos, response end else stdnse.print_debug( "Missing decoder for %d", header.type ) return -1, ("Missing decoder for %d"):format(header.type) end return -1, "Decoding failed" end, --- Attempts to authenticate to the pgsql server -- Supports plain-text and MD5 authentication -- -- @param socket socket already connected to the pgsql server -- @param params table containing any additional parameters <code>authtype</code>, <code>version</code> -- @param username string containing the username to use for authentication -- @param password string containing the password to use for authentication -- @param salt string containing the crypthographic salt value -- @return status true on success, false on failure -- @return result table containing parameter status information, -- result string containing an error message if login fails loginRequest = function ( socket, params, username, password, salt ) local catch = function() socket:close() stdnse.print_debug("loginRequest(): failed") end local try = nmap.new_try(catch) local response, header = {}, {} local status, data, len, tmp, _ local pos = 1 if ( params.authtype == AuthenticationType.MD5 ) then local hash = createMD5LoginHash(username, password, salt) data = bin.pack( "C>Iz", MessageType.PasswordMessage, 40, hash ) try( socket:send( data ) ) elseif ( params.authtype == AuthenticationType.Plain ) then local data data = bin.pack("C>Iz", MessageType.PasswordMessage, password:len() + 4, password) try( socket:send( data ) ) elseif ( params.authtype == AuthenticationType.Success ) then return true, nil end data, response.params = "", {} data = v3.readPacket(socket, data, 1) pos, tmp = v3.processResponse(data, 1) -- this should contain the AuthRequest packet if tmp.type ~= MessageType.AuthRequest then return false, "Expected AuthRequest got something else" end if not tmp.success then return false, "Login failure" end repeat data = v3.readPacket(socket, data, pos) pos, tmp = v3.processResponse(data, pos) if ( tmp.type == MessageType.ParameterStatus ) then table.insert(response.params, {name=tmp.key, value=tmp.value}) end until pos >= data:len() or pos == -1 return true, response end, --- Sends a startup message to the server containing the username and database to connect to -- -- @param socket socket already connected to the pgsql server -- @param user string containing the name of the user -- @param database string containing the name of the database -- @return status true on success, false on failure -- @return table containing a processed response from <code>processResponse</code> -- string containing error message if status is false sendStartup = function(socket, user, database ) local data, response, status, pos local proto_ver, ptype, _, tmp proto_ver = 0x0030000 data = bin.pack(">IzzzzH", proto_ver, "user", user, "database", database, 0) data = bin.pack(">I", data:len() + 4) .. data socket:send( data ) -- attempt to verify version status, data = socket:receive_bytes( 2 ) if ( not(status) ) then return false, "sendStartup failed" end if ( not(status) or data:match("^EF") ) then return false, "Incorrect version" end data = v3.readPacket(socket, data ) pos, response = v3.processResponse( data ) if ( pos < 0 or response.type == MessageType.Error) then return false, response.error.message or "unknown error" end return true, response end } --- Sends a packet requesting SSL communication to be activated -- -- @param socket socket already connected to the pgsql server -- @return boolean true if request was accepted, false if request was denied function requestSSL(socket) -- SSLRequest local ssl_req_code = 80877103 local data = bin.pack( ">I>I", 8, ssl_req_code) local status, response socket:send(data) status, response = socket:receive_bytes(1) if ( not(status) ) then return false end if ( response == 'S' ) then return true end return false end --- Creates a cryptographic hash to be used for login -- -- @param username username -- @param password password -- @param salt salt -- @return string suitable for login request function createMD5LoginHash(username, password, salt) local md5_1 = select( 2, bin.unpack( "H16", openssl.md5(password..username) ) ):lower() return "md5" .. select( 2, bin.unpack("H16", openssl.md5( md5_1 .. salt ) ) ):lower() end --- Prints the contents of the error table returned from the Error message decoder -- -- @param dberror table containing the error function printErrorMessage( dberror ) if not dberror then return end for k, v in pairs(dberror) do stdnse.print_debug( ("%s=%s"):format(k, v) ) end end --- Attempts to determine if the server supports v3 or v2 of the protocol -- -- @param host table -- @param port table -- @return class v2 or v3 function detectVersion(host, port) local status, response local socket = nmap.new_socket() socket:connect(host, port) status, response = v3.sendStartup(socket, "versionprobe", "versionprobe") socket:close() if ( not(status) and response == 'Incorrect version' ) then return v2 end return v3 end return _ENV;