Use ed25519 ssh private key as nkey seed

configuration_flags.go

@@ -72,6 +72,8 @@ type Configuration struct {
 	NkeySeedFile string `comment:"Full path to the NKEY's seed file"`
 	// The full path to the NKEY user file
 	NkeyPublicKey string `toml:"-"`
+	//
+	NkeyFromED25519SSHKeyFile string `comment:"Full path to the ED25519 SSH private key. Will generate the NKEY Seed from an SSH ED25519 private key file. NB: This option will take precedence over NkeySeedFile if specified"`
 	// The host and port to expose the data folder, <host>:<port>
 	ExposeDataFolder string `comment:"The host and port to expose the data folder, <host>:<port>"`
 	// Timeout in seconds for error messages
@@ -177,6 +179,7 @@ type ConfigurationFromFile struct {
 	CentralNodeName              *string
 	RootCAPath                   *string
 	NkeySeedFile                 *string
+	NkeyFromED25519SSHKeyFile    *string
 	ExposeDataFolder             *string
 	ErrorMessageTimeout          *int
 	ErrorMessageRetries          *int
@@ -248,6 +251,7 @@ func newConfigurationDefaults() Configuration {
 		CentralNodeName:              "",
 		RootCAPath:                   "",
 		NkeySeedFile:                 "",
+		NkeyFromED25519SSHKeyFile:    "",
 		ExposeDataFolder:             "",
 		ErrorMessageTimeout:          60,
 		ErrorMessageRetries:          10,
@@ -422,6 +426,11 @@ func checkConfigValues(cf ConfigurationFromFile) Configuration {
 	} else {
 		conf.NkeySeedFile = *cf.NkeySeedFile
 	}
+	if cf.NkeyFromED25519SSHKeyFile == nil {
+		conf.NkeyFromED25519SSHKeyFile = cd.NkeyFromED25519SSHKeyFile
+	} else {
+		conf.NkeyFromED25519SSHKeyFile = *cf.NkeyFromED25519SSHKeyFile
+	}
 	if cf.ExposeDataFolder == nil {
 		conf.ExposeDataFolder = cd.ExposeDataFolder
 	} else {
@@ -648,7 +657,8 @@ func (c *Configuration) CheckFlags(version string) error {
 	flag.StringVar(&c.SubscribersDataFolder, "subscribersDataFolder", fc.SubscribersDataFolder, "The data folder where subscribers are allowed to write their data if needed")
 	flag.StringVar(&c.CentralNodeName, "centralNodeName", fc.CentralNodeName, "The name of the central node to receive messages published by this node")
 	flag.StringVar(&c.RootCAPath, "rootCAPath", fc.RootCAPath, "If TLS, enter the path for where to find the root CA certificate")
-	flag.StringVar(&c.NkeySeedFile, "nkeySeedFile", fc.NkeySeedFile, "The full path of the nkeys seed file")
+	flag.StringVar(&c.NkeyFromED25519SSHKeyFile, "nkeyFromED25519SSHKeyFile", fc.NkeyFromED25519SSHKeyFile, "The full path of the nkeys seed file")
+	flag.StringVar(&c.NkeySeedFile, "nkeySeedFile", fc.NkeySeedFile, "Full path to the ED25519 SSH private key. Will generate the NKEY Seed from an SSH ED25519 private key file. NB: This option will take precedence over NkeySeedFile if specified")
 	flag.StringVar(&c.ExposeDataFolder, "exposeDataFolder", fc.ExposeDataFolder, "If set the data folder will be exposed on the given host:port. Default value is not exposed at all")
 	flag.IntVar(&c.ErrorMessageTimeout, "errorMessageTimeout", fc.ErrorMessageTimeout, "The number of seconds to wait for an error message to time out")
 	flag.IntVar(&c.ErrorMessageRetries, "errorMessageRetries", fc.ErrorMessageRetries, "The number of if times to retry an error message before we drop it")

go.mod

@@ -13,11 +13,13 @@ require (
 	github.com/klauspost/compress v1.16.3
 	github.com/nats-io/nats-server/v2 v2.8.4
 	github.com/nats-io/nats.go v1.25.0
+	github.com/nats-io/nkeys v0.4.4
 	github.com/pelletier/go-toml/v2 v2.0.7
 	github.com/pkg/profile v1.7.0
 	github.com/prometheus/client_golang v1.14.0
 	github.com/rivo/tview v0.0.0-20230330183452-5796b0cd5c1f
 	go.etcd.io/bbolt v1.3.7
+	golang.org/x/crypto v0.7.0
 	golang.org/x/exp v0.0.0-20230321023759-10a507213a29
 	gopkg.in/yaml.v3 v3.0.1
 )
@@ -37,14 +39,12 @@ require (
 	github.com/matttproud/golang_protobuf_extensions v1.0.4 // indirect
 	github.com/minio/highwayhash v1.0.2 // indirect
 	github.com/nats-io/jwt/v2 v2.2.1-0.20220330180145-442af02fd36a // indirect
-	github.com/nats-io/nkeys v0.4.4 // indirect
 	github.com/nats-io/nuid v1.0.1 // indirect
 	github.com/prometheus/client_model v0.3.0 // indirect
 	github.com/prometheus/common v0.42.0 // indirect
 	github.com/prometheus/procfs v0.9.0 // indirect
 	github.com/rivo/uniseg v0.4.4 // indirect
 	github.com/x448/float16 v0.8.4 // indirect
-	golang.org/x/crypto v0.7.0 // indirect
 	golang.org/x/sys v0.6.0 // indirect
 	golang.org/x/term v0.6.0 // indirect
 	golang.org/x/text v0.8.0 // indirect

nkey_from_ssh_ed25519_key.go

@@ -0,0 +1,226 @@
+package steward
+
+import (
+	"bytes"
+	"crypto/ed25519"
+	"encoding/base32"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"reflect"
+
+	"github.com/nats-io/nats.go"
+	"github.com/nats-io/nkeys"
+	"golang.org/x/crypto/ssh"
+)
+
+// nkeyOptFromSSHKey will read the ED25519 SSH private key file,
+// then convert the content into a NKEY Seed file, and return
+// the result as a nats.Option.
+func (c *Configuration) nkeyOptFromSSHKey() (nats.Option, error) {
+	// --- Create key
+	p, err := c.CreateKeyPair(PrefixByteUser)
+	if err != nil {
+		return nil, fmt.Errorf("error: createpair failed: %v", err)
+	}
+
+	filepathSeed := filepath.Join(c.SocketFolder, "seed_from_ssh_key.txt")
+	filepathUser := filepath.Join(c.SocketFolder, "user_from_ssh_key.txt")
+
+	// Write the private key seed to file.
+	{
+		fh, err := os.OpenFile(filepathSeed, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0660)
+		if err != nil {
+			return nil, fmt.Errorf("error: open file for writing seed failed: %v", err)
+		}
+		defer fh.Close()
+		_, err = fh.Write(p.seed)
+		if err != nil {
+			return nil, fmt.Errorf("error: writing of  seed file for ssh key failed: %v", err)
+		}
+	}
+	// Write the user key to file.
+	{
+		fh, err := os.OpenFile(filepathUser, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0660)
+		if err != nil {
+			return nil, fmt.Errorf("error: open file for writing user failed: %v", err)
+		}
+		defer fh.Close()
+		_, err = fh.Write([]byte(p.userKey))
+		if err != nil {
+			return nil, fmt.Errorf("error: writing of user file for ssh key failed: %v", err)
+		}
+	}
+
+	opt, err := nats.NkeyOptionFromSeed(filepathSeed)
+	if err != nil {
+		return nil, fmt.Errorf("error: creating option nkey from seed file failed: %v", err)
+	}
+
+	return opt, nil
+
+}
+
+// Convert the ed25519 public key to nkey user key.
+func publicKeyToUserKey(signer ssh.Signer) (string, error) {
+	key := signer.PublicKey()
+
+	marshalled := key.Marshal()
+	seed := marshalled[len(marshalled)-32:]
+
+	encoded, err := nkeys.Encode(nkeys.PrefixByteUser, seed)
+	if err != nil {
+		return "", err
+	}
+
+	return string(encoded), nil
+}
+
+type PrefixByte byte
+
+// PrefixByteUser is the version byte used for encoded NATS Users
+const PrefixByteUser PrefixByte = 20 << 3 // Base32-encodes to 'U...'
+
+type kp struct {
+	seed    []byte
+	userKey string
+}
+
+// CreateKeyPair will create the key nkeys key pair.
+// This is a slightly modified version of the function
+// found in the nkeys package, just with less options.
+func (c *Configuration) CreateKeyPair(prefix PrefixByte) (kp, error) {
+	fh, err := os.Open(c.NkeyFromED25519SSHKeyFile)
+	if err != nil {
+		return kp{}, fmt.Errorf("failed: open ssh private key file: %v", err)
+	}
+	defer fh.Close()
+
+	b, err := io.ReadAll(fh)
+	if err != nil {
+		return kp{}, fmt.Errorf("failed: read ssh private key file: %v", err)
+	}
+
+	signerRaw, err := ssh.ParseRawPrivateKey(b)
+	if err != nil {
+		return kp{}, fmt.Errorf("failed: parse raw private key: %v", err)
+	}
+
+	switch signerRaw.(type) {
+	case *ed25519.PrivateKey:
+		// ok, got correct type, just continue.
+	default:
+		t := reflect.TypeOf(signerRaw)
+		return kp{}, fmt.Errorf("failed: key is wrong type, want type ed25519 key, got: %v", t)
+	}
+	// ---
+	raw := signerRaw.(*ed25519.PrivateKey)
+	bytePrivAndPub := []byte(*raw)
+
+	seed, err := EncodeSeed(prefix, bytePrivAndPub[:32])
+	if err != nil {
+		return kp{}, err
+	}
+
+	signer, err := ssh.ParsePrivateKey(b)
+	if err != nil {
+		return kp{}, fmt.Errorf("failed: parse private key: %v", err)
+	}
+
+	pub, err := publicKeyToUserKey(signer)
+	if err != nil {
+		return kp{}, fmt.Errorf("failed: failed to get public key for signer: %v", err)
+	}
+
+	return kp{seed: seed, userKey: pub}, nil
+}
+
+// PrefixByteSeed is the version byte used for encoded NATS Seeds
+const PrefixByteSeed PrefixByte = 18 << 3 // Base32-encodes to 'S...'
+
+// EncodeSeed will encode a raw key with the prefix and then seed prefix and crc16 and then base32 encoded.
+// This is a slightly modified version of the function
+// found in the nkeys package, just with less options.
+func EncodeSeed(public PrefixByte, src []byte) ([]byte, error) {
+
+	if len(src) != ed25519.SeedSize {
+		return nil, fmt.Errorf("invalid key length")
+	}
+
+	// In order to make this human printable for both bytes, we need to do a little
+	// bit manipulation to setup for base32 encoding which takes 5 bits at a time.
+	b1 := byte(PrefixByteSeed) | (byte(public) >> 5)
+	b2 := (byte(public) & 31) << 3 // 31 = 00011111
+
+	var raw bytes.Buffer
+
+	raw.WriteByte(b1)
+	raw.WriteByte(b2)
+
+	// write payload
+	if _, err := raw.Write(src); err != nil {
+		return nil, err
+	}
+
+	// Calculate and write crc16 checksum
+	err := binary.Write(&raw, binary.LittleEndian, crc16(raw.Bytes()))
+	if err != nil {
+		return nil, err
+	}
+
+	data := raw.Bytes()
+	buf := make([]byte, b32Enc.EncodedLen(len(data)))
+	b32Enc.Encode(buf, data)
+	return buf, nil
+}
+
+// Set our encoding to not include padding '=='
+var b32Enc = base32.StdEncoding.WithPadding(base32.NoPadding)
+
+// crc16 returns the 2-byte crc for the data provided.
+// This is a slightly modified version of the function
+// found in the nkeys package, just with less options.
+func crc16(data []byte) uint16 {
+	var crc uint16
+	for _, b := range data {
+		crc = ((crc << 8) & 0xffff) ^ crc16tab[((crc>>8)^uint16(b))&0x00FF]
+	}
+	return crc
+}
+
+var crc16tab = [256]uint16{
+	0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
+	0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
+	0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
+	0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
+	0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
+	0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
+	0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
+	0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
+	0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
+	0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
+	0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
+	0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
+	0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
+	0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
+	0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
+	0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
+	0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
+	0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
+	0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
+	0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
+	0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
+	0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
+	0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
+	0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
+	0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
+	0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
+	0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
+	0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
+	0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
+	0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
+	0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
+	0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0,
+}

server.go

@@ -89,7 +89,7 @@ func NewServer(configuration *Configuration, version string) (*server, error) {
 		opt = nats.RootCAs(configuration.RootCAPath)
 	}
 
-	if configuration.NkeySeedFile != "" {
+	if configuration.NkeySeedFile != "" && configuration.NkeyFromED25519SSHKeyFile == "" {
 		var err error
 
 		opt, err = nats.NkeyOptionFromSeed(configuration.NkeySeedFile)
@@ -99,6 +99,16 @@ func NewServer(configuration *Configuration, version string) (*server, error) {
 		}
 	}
 
+	if configuration.NkeyFromED25519SSHKeyFile != "" {
+		var err error
+
+		opt, err = configuration.nkeyOptFromSSHKey()
+		if err != nil {
+			cancel()
+			return nil, fmt.Errorf("error: failed to read nkey seed file: %v", err)
+		}
+	}
+
 	var conn *nats.Conn
 
 	// Connect to the nats server, and retry until succesful.