Microsoft TPM Simulator TCTI (WIP)

tpm/internal/mssim/gotpm.go

@@ -0,0 +1,204 @@
+// Copyright (c) 2018, Google LLC All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package mssim implements the Microsoft simulator TPM2 Transmission Interface
+//
+// The Microsoft simulator TPM Command Transmission Interface (TCTI) is a
+// remote procedure interface donated to the TPM2 Specification by Microsoft.
+// Its primary implementation is the tpm_server maintained by IBM.
+//
+// https://sourceforge.net/projects/ibmswtpm2/
+//
+// This package implements client code to communicate with server code described
+// in the document "TPM2 Specification Part 4: Supporting Routines – Code"
+//
+// https://trustedcomputinggroup.org/wp-content/uploads/TPM-Rev-2.0-Part-4-Supporting-Routines-01.38-code.pdf
+//
+// This file was copied from https://github.com/google/go-tpm/tree/main/tpmutil/mssim.
+// Some small changes were made so that platform commands can be skipped based on
+// configuration.
+
+//nolint:errorlint,gocritic // copied package
+package mssim
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"net"
+)
+
+// Constants defined in "D.3.2. Typedefs and Defines"
+const (
+	tpmSignalPowerOn  uint32 = 1
+	tpmSignalPowerOff uint32 = 2
+	tpmSendCommand    uint32 = 8
+	tpmSignalNVOn     uint32 = 11
+	tpmSessionEnd     uint32 = 20
+)
+
+// Config holds configuration parameters for connecting to the simulator.
+type config struct {
+	// Addresses of the command and platform handlers.
+	//
+	// Defaults to port 2321 and 2322 on localhost.
+	commandAddress  string
+	platformAddress string
+
+	// Skip platform powerup/startup commands
+	skipPlatformCommands bool
+}
+
+// Open creates connections to the simulator's command and platform ports and
+// power cycles the simulator to initialize it.
+func open(config config) (*Conn, error) {
+	cmdAddr := config.commandAddress
+	if cmdAddr == "" {
+		cmdAddr = "127.0.0.1:2321"
+	}
+
+	if !config.skipPlatformCommands {
+		platformAddr := config.platformAddress
+		if platformAddr == "" {
+			platformAddr = "127.0.0.1:2322"
+		}
+
+		conn, err := net.Dial("tcp", platformAddr)
+		if err != nil {
+			return nil, fmt.Errorf("dial platform address: %v", err)
+		}
+		defer conn.Close()
+
+		// Startup the simulator. This order of commands copies IBM's TPM2 tool's
+		// "powerup" command line tool and will reset the simulator.
+		//
+		// https://sourceforge.net/projects/ibmtpm20tss/
+
+		if err := sendPlatformCommand(conn, tpmSignalPowerOff); err != nil {
+			return nil, fmt.Errorf("power off platform command failed: %v", err)
+		}
+		if err := sendPlatformCommand(conn, tpmSignalPowerOn); err != nil {
+			return nil, fmt.Errorf("power on platform command failed: %v", err)
+		}
+		if err := sendPlatformCommand(conn, tpmSignalNVOn); err != nil {
+			return nil, fmt.Errorf("nv on platform command failed: %v", err)
+		}
+
+		// Gracefully close the connection.
+		if err := binary.Write(conn, binary.BigEndian, tpmSessionEnd); err != nil {
+			return nil, fmt.Errorf("shutdown platform connection failed: %v", err)
+		}
+	}
+
+	cmdConn, err := net.Dial("tcp", cmdAddr)
+	if err != nil {
+		return nil, fmt.Errorf("dial command address: %v", err)
+	}
+
+	return &Conn{conn: cmdConn}, nil
+}
+
+// sendPlatformCommand sends device management commands to the simulator.
+//
+// See: "D.4.3.2. PlatformServer()"
+func sendPlatformCommand(conn net.Conn, u uint32) error {
+	if err := binary.Write(conn, binary.BigEndian, u); err != nil {
+		return fmt.Errorf("write platform command: %v", err)
+	}
+
+	var rc uint32
+	if err := binary.Read(conn, binary.BigEndian, &rc); err != nil {
+		return fmt.Errorf("read platform command: %v", err)
+	}
+	if rc != 0 {
+		return fmt.Errorf("unexpected platform command response code: 0x%x", rc)
+	}
+	return nil
+}
+
+// Conn is a Microsoft Simulator client that can be used as a connection for the
+// tpm2 package.
+type Conn struct {
+	// Cached connection
+	conn net.Conn
+
+	// Response bytes left over from the previous read.
+	prevRead *bytes.Reader
+}
+
+// Read a response from the simulator. If the response is longer than the provided
+// buffer, the remainder will be cached for the next read.
+func (c *Conn) Read(b []byte) (int, error) {
+	if c.prevRead != nil && c.prevRead.Len() > 0 {
+		return c.prevRead.Read(b)
+	}
+
+	// Response frame:
+	// - uint32 (size of response)
+	// - []byte (response)
+	// - uint32 (always 0)
+	var respLen uint32
+	if err := binary.Read(c.conn, binary.BigEndian, &respLen); err != nil {
+		return 0, fmt.Errorf("read MS simulator response header: %v", err)
+	}
+
+	resp := make([]byte, int(respLen))
+	if _, err := io.ReadFull(c.conn, resp[:]); err != nil {
+		return 0, fmt.Errorf("read MS simulator response: %v", err)
+	}
+
+	var rc uint32
+	if err := binary.Read(c.conn, binary.BigEndian, &rc); err != nil {
+		return 0, fmt.Errorf("read MS simulator return code: %v", err)
+	}
+	if rc != 0 {
+		return 0, fmt.Errorf("MS simulator returned invalid return code: 0x%x", rc)
+	}
+
+	c.prevRead = bytes.NewReader(resp)
+	return c.prevRead.Read(b)
+}
+
+// Write a raw command to the simulator. Commands must be written in a single call
+// to Write. Commands split over multiple calls will result in multiple framed
+// requests.
+func (c *Conn) Write(b []byte) (int, error) {
+	// See: D.4.3.12. TpmServer()
+	buff := &bytes.Buffer{}
+	// "send command" flag
+	binary.Write(buff, binary.BigEndian, tpmSendCommand)
+	// locality 0
+	buff.WriteByte(0)
+	// size of the command
+	binary.Write(buff, binary.BigEndian, uint32(len(b)))
+	// raw command
+	buff.Write(b)
+
+	if _, err := buff.WriteTo(c.conn); err != nil {
+		return 0, fmt.Errorf("write MS simulator command: %v", err)
+	}
+	return len(b), nil
+}
+
+// Close closes any outgoing connections to the TPM simulator.
+func (c *Conn) Close() error {
+	// See: D.4.3.12. TpmServer()
+	// Gracefully close the connection.
+	if err := binary.Write(c.conn, binary.BigEndian, tpmSessionEnd); err != nil {
+		c.conn.Close()
+		return fmt.Errorf("shutdown platform connection failed: %v", err)
+	}
+	return c.conn.Close()
+}

tpm/internal/mssim/mssim.go

@@ -0,0 +1,50 @@
+package mssim
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"strconv"
+
+	"go.step.sm/crypto/kms/uri"
+)
+
+func New(u *uri.URI) (rwc io.ReadWriteCloser, err error) {
+	host := "127.0.0.1"
+	port := 2321
+	if h := u.Get("host"); h != "" {
+		host = h
+	}
+	if p := u.Get("port"); p != "" {
+		port, err = strconv.Atoi(p)
+		if err != nil {
+			return nil, fmt.Errorf("failed parsing %q as integer: %w", p, err)
+		}
+	}
+
+	c := config{
+		commandAddress:       net.JoinHostPort(host, fmt.Sprint(port)),
+		platformAddress:      net.JoinHostPort(host, fmt.Sprint(port+1)),
+		skipPlatformCommands: true, // TODO(hs): assumes these steps are performed out of band; does that make sense?
+	}
+
+	rwc, err = open(c)
+	if err != nil {
+		return nil, fmt.Errorf("failed opening connection to TPM: %w", err)
+	}
+
+	// TODO(hs): make connection open lazily? And/or support connection management internally?
+	// Sometimes it happens that the connection is very slow, or there seems to be no connection
+	// at all. This is likely due to how we've implemented opening the TPM (once, generally), and
+	// then reusing that instance.
+
+	return
+}
+
+type CommandChannelWithoutMeasurementLog struct {
+	io.ReadWriteCloser
+}
+
+func (c *CommandChannelWithoutMeasurementLog) MeasurementLog() ([]byte, error) {
+	return nil, nil
+}

tpm/internal/open/open.go

@@ -1,9 +1,26 @@
 package open
 
 import (
+	"fmt"
 	"io"
+	"strings"
+
+	"go.step.sm/crypto/kms/uri"
+	"go.step.sm/crypto/tpm/internal/mssim"
 )
 
 func TPM(deviceName string) (io.ReadWriteCloser, error) {
+	if strings.HasPrefix(deviceName, "mssim:") {
+		u, err := uri.ParseWithScheme("mssim", deviceName)
+		if err != nil {
+			return nil, fmt.Errorf("failed parsing %q: %w", deviceName, err)
+		}
+		rwc, err := mssim.New(u)
+		if err != nil {
+			return nil, err
+		}
+		return rwc, nil
+	}
+
 	return open(deviceName)
 }

tpm/manufacturer/manufacturers.go

@@ -38,7 +38,7 @@ func GetEncodings(id ID) (ascii, hexa string) {
 // GetNameByASCII returns the manufacturer name based on its
 // ASCII identifier.
 func GetNameByASCII(ascii string) string {
-	if name, ok := manufacturerByASCII[ascii]; ok {
+	if name, ok := manufacturerByASCII[strings.TrimSpace(ascii)]; ok {
 		return name
 	}
 	return "unknown"

tpm/tpm.go

@@ -6,11 +6,14 @@
 	"fmt"
 	"io"
 	"net/http"
+	"strings"
 	"sync"
 
 	"github.com/smallstep/go-attestation/attest"
 
+	"go.step.sm/crypto/kms/uri"
 	closer "go.step.sm/crypto/tpm/internal/close"
+	"go.step.sm/crypto/tpm/internal/mssim"
 	"go.step.sm/crypto/tpm/internal/open"
 	"go.step.sm/crypto/tpm/internal/socket"
 	"go.step.sm/crypto/tpm/simulator"
@@ -230,19 +233,30 @@
 		t.commandChannel = t.options.commandChannel
 	}
 
-	// finally, check if the device name points to a UNIX socket, and use that
-	// as the command channel, if available.
 	if t.commandChannel == nil {
-		if socketCommandChannel, err := trySocketCommandChannel(t.deviceName); err != nil {
-			switch {
-			case errors.Is(err, socket.ErrNotSupported):
-				// don't try to use socket command channel if not supported. No need to return
-				// an error, because the code should still rely on the default TPM command channel.
-			case !errors.Is(err, socket.ErrNotAvailable):
-				return err
+		switch {
+		case strings.HasPrefix(t.deviceName, "mssim:"):
+			// if the TPM device name looks like a URI that starts with "mssim:", try
+			// using a TCP connection to the TPM using the Microsoft PTM simulator TCTI.
+			msSimCommandChannel, err := tryMsSimCommandChannel(t.deviceName)
+			if err != nil {
+				return fmt.Errorf("invalid Microsoft TPM Simulator device name %q: %w", t.deviceName, err)
+			}
+			t.commandChannel = msSimCommandChannel
+		default:
+			// finally, check if the device name points to a UNIX socket, and use that
+			// as the command channel, if available.
+			if socketCommandChannel, err := trySocketCommandChannel(t.deviceName); err != nil {
+				switch {
+				case errors.Is(err, socket.ErrNotSupported):
+					// don't try to use socket command channel if not supported. No need to return
+					// an error, because the code should still rely on the default TPM command channel.
+				case !errors.Is(err, socket.ErrNotAvailable):
+					return err
+				}
+			} else {
+				t.commandChannel = socketCommandChannel
 			}
-		} else {
-			t.commandChannel = socketCommandChannel
 		}
 	}
 
@@ -257,7 +271,8 @@
 	return nil
 }
 
-// trySocketCommandChannel tries
+// trySocketCommandChannel tries to establish connections to a TPM using
+// a UNIX socket.
 func trySocketCommandChannel(path string) (*socket.CommandChannelWithoutMeasurementLog, error) {
 	rwc, err := socket.New(path)
 	if err != nil {
@@ -266,6 +281,20 @@
 	return &socket.CommandChannelWithoutMeasurementLog{ReadWriteCloser: rwc}, nil
 }
 
+// tryMsSimCommandChannel tries to establish connections to a TPM using the
+// Microsoft TPM Simulator TCTI.
+func tryMsSimCommandChannel(rawuri string) (*mssim.CommandChannelWithoutMeasurementLog, error) {
+	u, err := uri.ParseWithScheme("mssim", rawuri)
+	if err != nil {
+		return nil, fmt.Errorf("failed parsing %q: %w", rawuri, err)
+	}
+	rwc, err := mssim.New(u)
+	if err != nil {
+		return nil, err
+	}
+	return &mssim.CommandChannelWithoutMeasurementLog{ReadWriteCloser: rwc}, nil
+}
+
 // Close closes the TPM instance, cleaning up resources and
 // marking it ready to be use again.
 func (t *TPM) close(ctx context.Context) error {