import new ssh crypto (#220)

cmd/sshpiperd/daemon.go

@@ -1,7 +1,10 @@
 package main
 
 import (
+	"crypto/ed25519"
+	"crypto/rand"
 	"encoding/base64"
+	"encoding/pem"
 	"fmt"
 	"net"
 	"os"
@@ -24,6 +27,22 @@ type daemon struct {
 	filterHostkeysReqeust bool
 }
 
+func generateSshKey(keyfile string) error {
+	_, privateKey, err := ed25519.GenerateKey(rand.Reader)
+	if err != nil {
+		return err
+	}
+
+	privateKeyPEM, err := ssh.MarshalPrivateKey(privateKey, "")
+	if err != nil {
+		return err
+	}
+
+	privateKeyBytes := pem.EncodeToMemory(privateKeyPEM)
+
+	return os.WriteFile(keyfile, privateKeyBytes, 0600)
+}
+
 func newDaemon(ctx *cli.Context) (*daemon, error) {
 	config := &plugin.GrpcPluginConfig{}
 	config.SetDefaults()

cmd/sshpiperd/key.go

@@ -1,112 +0,0 @@
-package main
-
-import (
-	"crypto/ed25519"
-	crand "crypto/rand"
-	"encoding/pem"
-	"math/rand"
-	"os"
-
-	"golang.org/x/crypto/ssh"
-)
-
-func generateSshKey(keyfile string) error {
-	_, privateKey, err := ed25519.GenerateKey(crand.Reader)
-	if err != nil {
-		return err
-	}
-
-	privateKeyPEM := &pem.Block{
-		Type:  "OPENSSH PRIVATE KEY",
-		Bytes: marshalED25519PrivateKey(privateKey),
-	}
-
-	privateKeyBytes := pem.EncodeToMemory(privateKeyPEM)
-
-	return os.WriteFile(keyfile, privateKeyBytes, 0600)
-}
-
-// copy from https://github.com/mikesmitty/edkey/blob/master/edkey.go
-
-/*
-	Writes ed25519 private keys into the new OpenSSH private key format.
-
-I have no idea why this isn't implemented anywhere yet, you can do seemingly
-everything except write it to disk in the OpenSSH private key format.
-*/
-func marshalED25519PrivateKey(key ed25519.PrivateKey) []byte {
-	// Add our key header (followed by a null byte)
-	magic := append([]byte("openssh-key-v1"), 0)
-
-	var w struct {
-		CipherName   string
-		KdfName      string
-		KdfOpts      string
-		NumKeys      uint32
-		PubKey       []byte
-		PrivKeyBlock []byte
-	}
-
-	// Fill out the private key fields
-	pk1 := struct {
-		Check1  uint32
-		Check2  uint32
-		Keytype string
-		Pub     []byte
-		Priv    []byte
-		Comment string
-		Pad     []byte `ssh:"rest"`
-	}{}
-
-	// Set our check ints
-	ci := rand.Uint32()
-	pk1.Check1 = ci
-	pk1.Check2 = ci
-
-	// Set our key type
-	pk1.Keytype = ssh.KeyAlgoED25519
-
-	// Add the pubkey to the optionally-encrypted block
-	pk, ok := key.Public().(ed25519.PublicKey)
-	if !ok {
-		//fmt.Fprintln(os.Stderr, "ed25519.PublicKey type assertion failed on an ed25519 public key. This should never ever happen.")
-		return nil
-	}
-	pubKey := []byte(pk)
-	pk1.Pub = pubKey
-
-	// Add our private key
-	pk1.Priv = []byte(key)
-
-	// Might be useful to put something in here at some point
-	pk1.Comment = ""
-
-	// Add some padding to match the encryption block size within PrivKeyBlock (without Pad field)
-	// 8 doesn't match the documentation, but that's what ssh-keygen uses for unencrypted keys. *shrug*
-	bs := 8
-	blockLen := len(ssh.Marshal(pk1))
-	padLen := (bs - (blockLen % bs)) % bs
-	pk1.Pad = make([]byte, padLen)
-
-	// Padding is a sequence of bytes like: 1, 2, 3...
-	for i := 0; i < padLen; i++ {
-		pk1.Pad[i] = byte(i + 1)
-	}
-
-	// Generate the pubkey prefix "\0\0\0\nssh-ed25519\0\0\0 "
-	prefix := []byte{0x0, 0x0, 0x0, 0x0b}
-	prefix = append(prefix, []byte(ssh.KeyAlgoED25519)...)
-	prefix = append(prefix, []byte{0x0, 0x0, 0x0, 0x20}...)
-
-	// Only going to support unencrypted keys for now
-	w.CipherName = "none"
-	w.KdfName = "none"
-	w.KdfOpts = ""
-	w.NumKeys = 1
-	w.PubKey = append(prefix, pubKey...)
-	w.PrivKeyBlock = ssh.Marshal(pk1)
-
-	magic = append(magic, ssh.Marshal(w)...)
-
-	return magic
-}