Some incomplete initial code

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

.gitignore

@@ -0,0 +1 @@
+onerng

cmd/flush.go

@@ -0,0 +1,20 @@
+package cmd
+
+import (
+	"context"
+
+	"github.com/hairyhenderson/go-onerng"
+	"github.com/spf13/cobra"
+)
+
+// flushCmd represents the flush command
+func flushCmd(ctx context.Context) *cobra.Command {
+	return &cobra.Command{
+		Use:   "flush",
+		Short: "Flush the OneRNG's entropy pool",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			o := onerng.OneRNG{Path: opts.Device}
+			return o.Flush(ctx)
+		},
+	}
+}

cmd/id.go

@@ -0,0 +1,26 @@
+package cmd
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/hairyhenderson/go-onerng"
+	"github.com/spf13/cobra"
+)
+
+// idCmd represents the id command
+func idCmd(ctx context.Context) *cobra.Command {
+	return &cobra.Command{
+		Use:   "id",
+		Short: "Display the OneRNG's hardware id",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			o := onerng.OneRNG{Path: opts.Device}
+			id, err := o.Identify(ctx)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("OneRNG Hardware ID: %s\n", id)
+			return nil
+		},
+	}
+}

cmd/image.go

@@ -0,0 +1,26 @@
+package cmd
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/hairyhenderson/go-onerng"
+	"github.com/spf13/cobra"
+)
+
+// imageCmd represents the image command
+func imageCmd(ctx context.Context) *cobra.Command {
+	return &cobra.Command{
+		Use:   "image",
+		Short: "Dump the OneRNG's firmware image",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			o := onerng.OneRNG{Path: opts.Device}
+			image, err := o.Image(ctx)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("%q\n", image)
+			return nil
+		},
+	}
+}

cmd/onerng/main.go

@@ -0,0 +1,31 @@
+package main
+
+import (
+	"context"
+	"os"
+	"os/signal"
+	"time"
+
+	"github.com/hairyhenderson/go-onerng/cmd"
+)
+
+func main() {
+	ctx := context.Background()
+
+	ctx, cancel := context.WithDeadline(ctx, time.Now().Add(3*time.Second))
+	c := make(chan os.Signal, 1)
+	signal.Notify(c, os.Interrupt)
+	defer func() {
+		signal.Stop(c)
+		cancel()
+	}()
+	go func() {
+		select {
+		case <-c:
+			cancel()
+		case <-ctx.Done():
+		}
+	}()
+
+	cmd.Execute(ctx)
+}

cmd/root.go

@@ -0,0 +1,73 @@
+package cmd
+
+import (
+	"context"
+	"fmt"
+	"os"
+
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+)
+
+var (
+	cfgFile string
+	opts    Config
+)
+
+func rootCmd(ctx context.Context) *cobra.Command {
+	return &cobra.Command{
+		Use:   "onerng [opts] COMMAND",
+		Short: "Tool for the OneRNG open source hardware entropy generator",
+		Long: `OneRNG is an open source hardware entropy generator in a USB dongle.
+
+This tool can be used to verify that the OneRNG device operates
+correctly, and that the firmware has not been tampered with.`,
+		PersistentPreRunE: func(cmd *cobra.Command, args []string) error {
+			cmd.SilenceErrors = true
+			cmd.SilenceUsage = true
+			return nil
+		},
+	}
+}
+
+// Execute -
+func Execute(ctx context.Context) {
+	cmd := rootCmd(ctx)
+	initConfig(ctx, cmd)
+	if err := cmd.Execute(); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+
+func initConfig(ctx context.Context, cmd *cobra.Command) {
+	cmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.go-onerng.yaml)")
+	opts = Config{}
+	cmd.PersistentFlags().StringVarP(&opts.Device, "device", "d", "/dev/ttyACM0", "the OneRNG device")
+
+	cmd.AddCommand(
+		verifyCmd(ctx),
+		versionCmd(ctx),
+		idCmd(ctx),
+		flushCmd(ctx),
+		imageCmd(ctx),
+	)
+
+	if cfgFile != "" { // enable ability to specify config file via flag
+		viper.SetConfigFile(cfgFile)
+	}
+
+	viper.SetConfigName(".go-onerng")      // name of config file (without extension)
+	viper.AddConfigPath(os.Getenv("HOME")) // adding home directory as first search path
+	viper.AutomaticEnv()                   // read in environment variables that match
+
+	// If a config file is found, read it in.
+	if err := viper.ReadInConfig(); err == nil {
+		fmt.Println("Using config file:", viper.ConfigFileUsed())
+	}
+}
+
+// Config -
+type Config struct {
+	Device string
+}

cmd/verify.go

@@ -0,0 +1,84 @@
+package cmd
+
+import (
+	"context"
+
+	"github.com/spf13/cobra"
+)
+
+const (
+	publicKey = `-----BEGIN PGP PUBLIC KEY BLOCK-----
+Version: GnuPG v1
+
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+=IjnI
+-----END PGP PUBLIC KEY BLOCK-----
+`
+)
+
+func verifyCmd(ctx context.Context) *cobra.Command {
+	return &cobra.Command{
+		Use:   "verify",
+		Short: "Verify that OneRNG's firmware has not been tampered with.",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			return nil
+		},
+	}
+}

cmd/version.go

@@ -0,0 +1,26 @@
+package cmd
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/hairyhenderson/go-onerng"
+	"github.com/spf13/cobra"
+)
+
+// versionCmd represents the version command
+func versionCmd(ctx context.Context) *cobra.Command {
+	return &cobra.Command{
+		Use:   "version",
+		Short: "Display the OneRNG's hardware version",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			o := onerng.OneRNG{Path: opts.Device}
+			version, err := o.Version(ctx)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("OneRNG Hardware Version: %d\n", version)
+			return nil
+		},
+	}
+}

commands.go

@@ -0,0 +1,33 @@
+package onerng
+
+const (
+	// CmdVersion - print firmware version (as "Version n")
+	CmdVersion = "cmdv\n"
+	// CmdFlush - flush entropy pool
+	CmdFlush = "cmdw\n"
+	// CmdImage - extract the signed firmware image for verification
+	CmdImage = "cmdX\n"
+	// CmdID - print hardware ID
+	CmdID = "cmdI\n"
+	// CmdRun - start the task
+	CmdRun = "cmdO\n"
+	// CmdPause - stop/pause the task
+	CmdPause = "cmdo\n"
+
+	// CmdAvalancheWhitener - Avalanche noise with whitener (default)
+	CmdAvalancheWhitener = "cmd0\n"
+	// CmdAvalanche - Raw avalanche noise
+	CmdAvalanche = "cmd1\n"
+	// CmdAvalancheRFWhitener - Avalanche noise and RF noise with whitener
+	CmdAvalancheRFWhitener = "cmd2\n"
+	// CmdAvalancheRF - Raw avalanche noise and RF noise
+	CmdAvalancheRF = "cmd3\n"
+	// CmdSilent - No noise (necessary for image extraction)
+	CmdSilent = "cmd4\n"
+	// CmdSilent2 - No noise
+	CmdSilent2 = "cmd5\n"
+	// CmdRFWhitener - RF noise with whitener
+	CmdRFWhitener = "cmd6\n"
+	// CmdRF - Raw RF noise
+	CmdRF = "cmd7\n"
+)

onerng.go

@@ -0,0 +1,222 @@
+package onerng
+
+import (
+	"bufio"
+	"context"
+	"os"
+	"strconv"
+	"strings"
+
+	"github.com/pkg/errors"
+)
+
+// OneRNG - a OneRNG device
+type OneRNG struct {
+	Path string
+}
+
+func (o *OneRNG) cmd(ctx context.Context, d *os.File, c ...string) (err error) {
+	for _, v := range c {
+		_, err = d.WriteString(v)
+		if err != nil {
+			return errors.Wrapf(err, "Errored on command %s", v)
+		}
+		select {
+		case <-ctx.Done():
+			return nil
+		default:
+		}
+	}
+	return nil
+}
+
+// Version -
+func (o *OneRNG) Version(ctx context.Context) (int, error) {
+	d, err := os.OpenFile(o.Path, os.O_RDWR, 0600)
+	if err != nil {
+		return 0, err
+	}
+	defer d.Close()
+
+	_, cancel := context.WithCancel(ctx)
+	defer cancel()
+	buf := make(chan string)
+	errc := make(chan error, 1)
+	go func() {
+		defer close(buf)
+		defer close(errc)
+		scanner := bufio.NewScanner(d)
+		for scanner.Scan() {
+			select {
+			case <-ctx.Done():
+				return
+			case buf <- scanner.Text():
+			}
+		}
+	}()
+
+	err = o.cmd(ctx, d, CmdSilent, CmdVersion, CmdRun)
+	if err != nil {
+		return 0, err
+	}
+
+	verString := ""
+loop:
+	for {
+		var b string
+		select {
+		case <-ctx.Done():
+			return 0, ctx.Err()
+		case b = <-buf:
+			if strings.HasPrefix(b, "Version ") {
+				verString = b
+				cancel()
+				break loop
+			}
+		case err := <-errc:
+			return 0, err
+		}
+	}
+
+	err = o.cmd(ctx, d, CmdPause)
+	if err != nil {
+		return 0, err
+	}
+
+	n := strings.Replace(verString, "Version ", "", 1)
+	version, err := strconv.Atoi(n)
+	return version, err
+}
+
+// Identify -
+func (o *OneRNG) Identify(ctx context.Context) (string, error) {
+	d, err := os.OpenFile(o.Path, os.O_RDWR, 0600)
+	if err != nil {
+		return "", err
+	}
+	defer d.Close()
+
+	_, cancel := context.WithCancel(ctx)
+	defer cancel()
+	buf := make(chan string)
+	errc := make(chan error, 1)
+	go func() {
+		defer close(buf)
+		defer close(errc)
+		scanner := bufio.NewScanner(d)
+		for scanner.Scan() {
+			select {
+			case <-ctx.Done():
+				return
+			case buf <- scanner.Text():
+			}
+		}
+	}()
+
+	err = o.cmd(ctx, d, CmdSilent, CmdID, CmdRun)
+	if err != nil {
+		return "", err
+	}
+
+	idString := ""
+loop:
+	for {
+		var b string
+		select {
+		case <-ctx.Done():
+			return "", ctx.Err()
+		case b = <-buf:
+			if strings.HasPrefix(b, "___") {
+				idString = b
+				cancel()
+				break loop
+			}
+		case err := <-errc:
+			return "", err
+		}
+	}
+
+	err = o.cmd(ctx, d, CmdPause)
+	if err != nil {
+		return "", err
+	}
+
+	return idString, err
+}
+
+// Flush -
+func (o *OneRNG) Flush(ctx context.Context) error {
+	d, err := os.OpenFile(o.Path, os.O_RDWR, 0600)
+	if err != nil {
+		return err
+	}
+	defer d.Close()
+
+	_, cancel := context.WithCancel(ctx)
+	defer cancel()
+	err = o.cmd(ctx, d, CmdFlush)
+	return err
+}
+
+// Image -
+func (o *OneRNG) Image(ctx context.Context) ([]byte, error) {
+	d, err := os.OpenFile(o.Path, os.O_RDWR, 0600)
+	if err != nil {
+		return nil, err
+	}
+	defer d.Close()
+
+	_, cancel := context.WithCancel(ctx)
+	defer cancel()
+	buf := make(chan []byte)
+	errc := make(chan error, 1)
+	go func() {
+		defer close(buf)
+		defer close(errc)
+		b := make([]byte, 128)
+		for {
+			n, err := d.Read(b)
+			if err != nil {
+				errc <- err
+				return
+			}
+			select {
+			case <-ctx.Done():
+				return
+			case buf <- b:
+			}
+			if n == 0 {
+				return
+			}
+		}
+	}()
+
+	err = o.cmd(ctx, d, CmdSilent, CmdImage, CmdRun)
+	if err != nil {
+		return nil, err
+	}
+
+	image := []byte{}
+loop:
+	for {
+		var b []byte
+		select {
+		case <-ctx.Done():
+			return nil, ctx.Err()
+		case b = <-buf:
+			copy(image, b)
+			if len(b) == 0 {
+				break loop
+			}
+		case err := <-errc:
+			return nil, err
+		}
+	}
+
+	err = o.cmd(ctx, d, CmdPause)
+	if err != nil {
+		return nil, err
+	}
+
+	return image, err
+}