Refactor the generate_signing_key processing (#2430)

builtin/logical/ssh/path_config_ca.go

@@ -1,15 +1,15 @@
 package ssh
 
 import (
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
 	"fmt"
-	"github.com/hashicorp/vault/helper/errutil"
+
 	"github.com/hashicorp/vault/logical"
 	"github.com/hashicorp/vault/logical/framework"
 	"golang.org/x/crypto/ssh"
-	"crypto/rsa"
-	"encoding/pem"
-	"crypto/rand"
-	"crypto/x509"
 )
 
 func pathConfigCA(b *backend) *framework.Path {
@@ -27,7 +27,7 @@ func pathConfigCA(b *backend) *framework.Path {
 			"generate_signing_key": &framework.FieldSchema{
 				Type:        framework.TypeBool,
 				Description: `Generate SSH key pair internally rather than use the private_key and public_key fields.`,
-				Default: true,
+				Default:     true,
 			},
 		},
 
@@ -44,22 +44,50 @@ For security reasons, the private key cannot be retrieved later.`,
 }
 
 func (b *backend) pathCAWrite(req *logical.Request, data *framework.FieldData) (*logical.Response, error) {
-
-	var publicKey, privateKey string
 	var err error
-	if data.Get("generate_signing_key").(bool) {
+	publicKey := data.Get("public_key").(string)
-		publicKey, privateKey, err = generateSSHKeyPair()
+	privateKey := data.Get("private_key").(string)
-		if err != nil {
-			return nil, err
-		}
-	} else {
-		publicKey, privateKey, err = parseSSHKeyPair(data)
 
-		if err != nil {
+	signingKeyGenerated := false
-			return nil, err
+	generateSigningKeyRaw, ok := data.GetOk("generate_signing_key")
+	if ok {
+		if generateSigningKeyRaw.(bool) {
+			if publicKey != "" || privateKey != "" {
+				return logical.ErrorResponse("public_key and private_key is not required when generate_signing_key is set to true"), nil
+			}
+
+			publicKey, privateKey, err = generateSSHKeyPair()
+			if err != nil {
+				return nil, err
+			}
+			signingKeyGenerated = true
 		}
 	}
 
+	if !signingKeyGenerated {
+		if publicKey == "" {
+			return logical.ErrorResponse("missing public_key"), nil
+		}
+
+		if privateKey == "" {
+			return logical.ErrorResponse("missing private_key"), nil
+		}
+
+		_, err := ssh.ParsePrivateKey([]byte(privateKey))
+		if err != nil {
+			return logical.ErrorResponse(fmt.Sprintf("Unable to parse private_key as an SSH private key: %v", err)), nil
+		}
+
+		_, err = parsePublicSSHKey(publicKey)
+		if err != nil {
+			return logical.ErrorResponse(fmt.Sprintf("Unable to parse public_key as an SSH public key: %v", err)), nil
+		}
+	}
+
+	if publicKey == "" || privateKey == "" {
+		return nil, fmt.Errorf("failed to generate or parse the keys")
+	}
+
 	err = req.Storage.Put(&logical.StorageEntry{
 		Key:   "public_key",
 		Value: []byte(publicKey),
@@ -81,7 +109,6 @@ func (b *backend) pathCAWrite(req *logical.Request, data *framework.FieldData) (
 	return nil, err
 }
 
-
 func generateSSHKeyPair() (string, string, error) {
 	privateSeed, err := rsa.GenerateKey(rand.Reader, 4096)
 	if err != nil {
@@ -89,9 +116,9 @@ func generateSSHKeyPair() (string, string, error) {
 	}
 
 	privateBlock := &pem.Block{
-		Type: "RSA PRIVATE KEY",
+		Type:    "RSA PRIVATE KEY",
 		Headers: nil,
-		Bytes: x509.MarshalPKCS1PrivateKey(privateSeed),
+		Bytes:   x509.MarshalPKCS1PrivateKey(privateSeed),
 	}
 
 	public, err := ssh.NewPublicKey(&privateSeed.PublicKey)
@@ -101,28 +128,3 @@ func generateSSHKeyPair() (string, string, error) {
 
 	return string(ssh.MarshalAuthorizedKey(public)), string(pem.EncodeToMemory(privateBlock)), nil
 }
-
-func parseSSHKeyPair(data *framework.FieldData) (string, string, error) {
-
-	publicKey := data.Get("public_key").(string)
-	if publicKey == "" {
-		return "", "", errutil.UserError{Err: `missing public_key`}
-	}
-
-	privateKey := data.Get("private_key").(string)
-	if privateKey == "" {
-		return "", "", errutil.UserError{Err: `missing public_key`}
-	}
-
-	_, err := ssh.ParsePrivateKey([]byte(privateKey))
-	if err != nil {
-		return "", "", errutil.UserError{Err: fmt.Sprintf(`Unable to parse "private_key" as an SSH private key: %s`, err)}
-	}
-
-	_, err = parsePublicSSHKey(publicKey)
-	if err != nil {
-		return "", "", errutil.UserError{Err: fmt.Sprintf(`Unable to parse "public_key" as an SSH public key: %s`, err)}
-	}
-
-	return publicKey, privateKey, nil
-}