From a5d1808efe3a2f58acfaed2b87c3fbef22c470bf Mon Sep 17 00:00:00 2001
From: Jeff Mitchell <jeff@hashicorp.com>
Date: Thu, 16 Mar 2017 11:14:17 -0400
Subject: [PATCH] Always include a hash of the public key and "vault" (to know
 where it (#2498)

came from) when generating a cert for SSH.

Follow on from #2494
---
 builtin/logical/ssh/backend_test.go |  6 +++---
 builtin/logical/ssh/path_roles.go   |  1 -
 builtin/logical/ssh/path_sign.go    | 24 +++++++++++++++++-------
 3 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/builtin/logical/ssh/backend_test.go b/builtin/logical/ssh/backend_test.go
index 37a348489e..538455c728 100644
--- a/builtin/logical/ssh/backend_test.go
+++ b/builtin/logical/ssh/backend_test.go
@@ -587,7 +587,7 @@ func TestBackend_ValidPrincipalsValidatedForHostCertificates(t *testing.T) {
 				},
 			}),
 
-			signCertificateStep("testing", "root", ssh.HostCert, []string{"dummy.example.org", "second.example.com"}, map[string]string{
+			signCertificateStep("testing", "vault-root-22608f5ef173aabf700797cb95c5641e792698ec6380e8e1eb55523e39aa5e51", ssh.HostCert, []string{"dummy.example.org", "second.example.com"}, map[string]string{
 				"option": "value",
 			}, map[string]string{
 				"extension": "extended",
@@ -632,7 +632,7 @@ func TestBackend_OptionsOverrideDefaults(t *testing.T) {
 				},
 			}),
 
-			signCertificateStep("testing", "root", ssh.UserCert, []string{"tuber"}, map[string]string{
+			signCertificateStep("testing", "vault-root-22608f5ef173aabf700797cb95c5641e792698ec6380e8e1eb55523e39aa5e51", ssh.UserCert, []string{"tuber"}, map[string]string{
 				"secondary": "value",
 			}, map[string]string{
 				"additional": "value",
@@ -709,7 +709,7 @@ func validateSSHCertificate(cert *ssh.Certificate, keyId string, certType int, v
 	ttl time.Duration) error {
 
 	if cert.KeyId != keyId {
-		return fmt.Errorf("Incorrect KeyId: %v", cert.KeyId)
+		return fmt.Errorf("Incorrect KeyId: %v, wanted %v", cert.KeyId, keyId)
 	}
 
 	if cert.CertType != uint32(certType) {
diff --git a/builtin/logical/ssh/path_roles.go b/builtin/logical/ssh/path_roles.go
index 679d38cc5e..907689f282 100644
--- a/builtin/logical/ssh/path_roles.go
+++ b/builtin/logical/ssh/path_roles.go
@@ -257,7 +257,6 @@ func pathRoles(b *backend) *framework.Path {
 			},
 			"allow_user_key_ids": &framework.FieldSchema{
 				Type: framework.TypeBool,
-				Default: true,
 				Description: `
 				[Not applicable for Dynamic type] [Not applicable for OTP type] [Optional for CA type]
 				If true, users can override the key ID for a signed certificate with the "key_id" field.
diff --git a/builtin/logical/ssh/path_sign.go b/builtin/logical/ssh/path_sign.go
index 7579601797..22e2513162 100644
--- a/builtin/logical/ssh/path_sign.go
+++ b/builtin/logical/ssh/path_sign.go
@@ -2,6 +2,8 @@ package ssh
 
 import (
 	"crypto/rand"
+	"crypto/sha256"
+	"encoding/hex"
 	"errors"
 	"fmt"
 	"strconv"
@@ -109,7 +111,7 @@ func (b *backend) pathSignCertificate(req *logical.Request, data *framework.Fiel
 
 	// Note that these various functions always return "user errors" so we pass
 	// them as 4xx values
-	keyId, err := b.calculateKeyId(data, req, role)
+	keyId, err := b.calculateKeyId(data, req, role, userPublicKey)
 	if err != nil {
 		return logical.ErrorResponse(err.Error()), nil
 	}
@@ -263,17 +265,25 @@ func (b *backend) calculateCertificateType(data *framework.FieldData, role *sshR
 	return certificateType, nil
 }
 
-func (b *backend) calculateKeyId(data *framework.FieldData, req *logical.Request, role *sshRole) (string, error) {
-	keyId := data.Get("key_id").(string)
+func (b *backend) calculateKeyId(data *framework.FieldData, req *logical.Request, role *sshRole, pubKey ssh.PublicKey) (string, error) {
+	reqId := data.Get("key_id").(string)
 
-	if keyId != "" && !role.AllowUserKeyIDs {
-		return "", fmt.Errorf("Setting key_id is not allowed by role")
+	if reqId != "" {
+		if !role.AllowUserKeyIDs {
+			return "", fmt.Errorf("setting key_id is not allowed by role")
+		}
+		return reqId, nil
 	}
 
-	if keyId == "" {
-		keyId = req.DisplayName
+	keyHash := sha256.Sum256(pubKey.Marshal())
+	keyId := hex.EncodeToString(keyHash[:])
+
+	if req.DisplayName != "" {
+		keyId = fmt.Sprintf("%s-%s", req.DisplayName, keyId)
 	}
 
+	keyId = fmt.Sprintf("vault-%s", keyId)
+
 	return keyId, nil
 }