connect: Support auth methods for the vault connect CA provider (#11573)

* Support vault auth methods for the Vault connect CA provider
* Rotate the token (re-authenticate to vault using auth method) when the token can no longer be renewed

.changelog/11573.txt

@@ -0,0 +1,5 @@
+```release-note:improvement
+connect: Support Vault auth methods for the Connect CA Vault provider. Currently, we support any non-deprecated auth methods
+the latest version of Vault supports (v1.8.5), which include AppRole, AliCloud, AWS, Azure, Cloud Foundry, GitHub, Google Cloud,
+JWT/OIDC, Kerberos, Kubernetes, LDAP, Oracle Cloud Infrastructure, Okta, Radius, TLS Certificates, and Username & Password.
+```

agent/connect/ca/provider_vault.go

@@ -8,9 +8,11 @@ import (
 	"fmt"
 	"io/ioutil"
 	"net/http"
+	"os"
 	"strings"
 	"time"
 
+	"github.com/hashicorp/consul/lib/decode"
 	"github.com/hashicorp/go-hclog"
 	vaultapi "github.com/hashicorp/vault/api"
 	"github.com/mitchellh/mapstructure"
@@ -19,7 +21,29 @@ import (
 	"github.com/hashicorp/consul/agent/structs"
 )
 
-const VaultCALeafCertRole = "leaf-cert"
+const (
+	VaultCALeafCertRole = "leaf-cert"
+
+	VaultAuthMethodTypeAliCloud     = "alicloud"
+	VaultAuthMethodTypeAppRole      = "approle"
+	VaultAuthMethodTypeAWS          = "aws"
+	VaultAuthMethodTypeAzure        = "azure"
+	VaultAuthMethodTypeCloudFoundry = "cf"
+	VaultAuthMethodTypeGitHub       = "github"
+	VaultAuthMethodTypeGCP          = "gcp"
+	VaultAuthMethodTypeJWT          = "jwt"
+	VaultAuthMethodTypeKerberos     = "kerberos"
+	VaultAuthMethodTypeKubernetes   = "kubernetes"
+	VaultAuthMethodTypeLDAP         = "ldap"
+	VaultAuthMethodTypeOCI          = "oci"
+	VaultAuthMethodTypeOkta         = "okta"
+	VaultAuthMethodTypeRadius       = "radius"
+	VaultAuthMethodTypeTLS          = "cert"
+	VaultAuthMethodTypeToken        = "token"
+	VaultAuthMethodTypeUserpass     = "userpass"
+
+	defaultK8SServiceAccountTokenPath = "/var/run/secrets/kubernetes.io/serviceaccount/token"
+)
 
 var ErrBackendNotMounted = fmt.Errorf("backend not mounted")
 var ErrBackendNotInitialized = fmt.Errorf("backend not initialized")
@@ -74,6 +98,13 @@ func (v *VaultProvider) Configure(cfg ProviderConfig) error {
 		return err
 	}
 
+	if config.AuthMethod != nil {
+		loginResp, err := vaultLogin(client, config.AuthMethod)
+		if err != nil {
+			return err
+		}
+		config.Token = loginResp.Auth.ClientToken
+	}
 	client.SetToken(config.Token)
 
 	// We don't want to set the namespace if it's empty to prevent potential
@@ -94,7 +125,7 @@ func (v *VaultProvider) Configure(cfg ProviderConfig) error {
 	if err != nil {
 		return err
 	} else if secret == nil {
-		return fmt.Errorf("Could not look up Vault provider token: not found")
+		return fmt.Errorf("could not look up Vault provider token: not found")
 	}
 	var token struct {
 		Renewable bool
@@ -105,7 +136,7 @@ func (v *VaultProvider) Configure(cfg ProviderConfig) error {
 	}
 
 	// Set up a renewer to renew the token automatically, if supported.
-	if token.Renewable {
+	if token.Renewable || config.AuthMethod != nil {
 		lifetimeWatcher, err := client.NewLifetimeWatcher(&vaultapi.LifetimeWatcherInput{
 			Secret: &vaultapi.Secret{
 				Auth: &vaultapi.SecretAuth{
@@ -118,10 +149,10 @@ func (v *VaultProvider) Configure(cfg ProviderConfig) error {
 			RenewBehavior: vaultapi.RenewBehaviorIgnoreErrors,
 		})
 		if err != nil {
-			return fmt.Errorf("Error beginning Vault provider token renewal: %v", err)
+			return fmt.Errorf("error beginning Vault provider token renewal: %v", err)
 		}
 
-		ctx, cancel := context.WithCancel(context.TODO())
+		ctx, cancel := context.WithCancel(context.Background())
 		v.shutdown = cancel
 		go v.renewToken(ctx, lifetimeWatcher)
 	}
@@ -129,7 +160,9 @@ func (v *VaultProvider) Configure(cfg ProviderConfig) error {
 	return nil
 }
 
-// renewToken uses a vaultapi.Renewer to repeatedly renew our token's lease.
+// renewToken uses a vaultapi.LifetimeWatcher to repeatedly renew our token's lease.
+// If the token can no longer be renewed and auth method is set,
+// it will re-authenticate to Vault using the auth method and restart the renewer with the new token.
 func (v *VaultProvider) renewToken(ctx context.Context, watcher *vaultapi.LifetimeWatcher) {
 	go watcher.Start()
 	defer watcher.Stop()
@@ -144,7 +177,35 @@ func (v *VaultProvider) renewToken(ctx context.Context, watcher *vaultapi.Lifeti
 				v.logger.Error("Error renewing token for Vault provider", "error", err)
 			}
 
-			// Watcher routine has finished, so start it again.
+			// If the watcher has exited and auth method is enabled,
+			// re-authenticate using the auth method and set up a new watcher.
+			if v.config.AuthMethod != nil {
+				// Login to Vault using the auth method.
+				loginResp, err := vaultLogin(v.client, v.config.AuthMethod)
+				if err != nil {
+					v.logger.Error("Error login in to Vault with %q auth method", v.config.AuthMethod.Type)
+					// Restart the watcher.
+					go watcher.Start()
+					continue
+				}
+
+				// Set the new token for the vault client.
+				v.client.SetToken(loginResp.Auth.ClientToken)
+				v.logger.Info("Successfully re-authenticated with Vault using auth method")
+
+				// Start the new watcher for the new token.
+				watcher, err = v.client.NewLifetimeWatcher(&vaultapi.LifetimeWatcherInput{
+					Secret:        loginResp,
+					RenewBehavior: vaultapi.RenewBehaviorIgnoreErrors,
+				})
+				if err != nil {
+					v.logger.Error("Error starting token renewal process")
+					go watcher.Start()
+					continue
+				}
+			}
+
+			// Restart the watcher.
 			go watcher.Start()
 
 		case <-watcher.RenewCh():
@@ -599,7 +660,10 @@ func ParseVaultCAConfig(raw map[string]interface{}) (*structs.VaultCAProviderCon
 	}
 
 	decodeConf := &mapstructure.DecoderConfig{
-		DecodeHook:       structs.ParseDurationFunc(),
+		DecodeHook: mapstructure.ComposeDecodeHookFunc(
+			structs.ParseDurationFunc(),
+			decode.HookTranslateKeys,
+		),
 		Result:           &config,
 		WeaklyTypedInput: true,
 	}
@@ -613,8 +677,12 @@ func ParseVaultCAConfig(raw map[string]interface{}) (*structs.VaultCAProviderCon
 		return nil, fmt.Errorf("error decoding config: %s", err)
 	}
 
-	if config.Token == "" {
+	if config.Token == "" && config.AuthMethod == nil {
-		return nil, fmt.Errorf("must provide a Vault token")
+		return nil, fmt.Errorf("must provide a Vault token or configure a Vault auth method")
+	}
+
+	if config.Token != "" && config.AuthMethod != nil {
+		return nil, fmt.Errorf("only one of Vault token or Vault auth method can be provided, but not both")
 	}
 
 	if config.RootPKIPath == "" {
@@ -637,3 +705,76 @@ func ParseVaultCAConfig(raw map[string]interface{}) (*structs.VaultCAProviderCon
 
 	return &config, nil
 }
+
+func vaultLogin(client *vaultapi.Client, authMethod *structs.VaultAuthMethod) (*vaultapi.Secret, error) {
+	// Adapted from https://www.vaultproject.io/docs/auth/kubernetes#code-example
+	loginPath, err := configureVaultAuthMethod(authMethod)
+	if err != nil {
+		return nil, err
+	}
+
+	resp, err := client.Logical().Write(loginPath, authMethod.Params)
+	if err != nil {
+		return nil, err
+	}
+	if resp == nil || resp.Auth == nil || resp.Auth.ClientToken == "" {
+		return nil, fmt.Errorf("login response did not return client token")
+	}
+
+	return resp, nil
+}
+
+func configureVaultAuthMethod(authMethod *structs.VaultAuthMethod) (loginPath string, err error) {
+	if authMethod.MountPath == "" {
+		authMethod.MountPath = authMethod.Type
+	}
+
+	switch authMethod.Type {
+	case VaultAuthMethodTypeKubernetes:
+		// For the Kubernetes Auth method, we will try to read the JWT token
+		// from the default service account file location if jwt was not provided.
+		if jwt, ok := authMethod.Params["jwt"]; !ok || jwt == "" {
+			serviceAccountToken, err := os.ReadFile(defaultK8SServiceAccountTokenPath)
+			if err != nil {
+				return "", err
+			}
+
+			authMethod.Params["jwt"] = string(serviceAccountToken)
+		}
+		loginPath = fmt.Sprintf("auth/%s/login", authMethod.MountPath)
+	// These auth methods require a username for the login API path.
+	case VaultAuthMethodTypeLDAP, VaultAuthMethodTypeUserpass, VaultAuthMethodTypeOkta, VaultAuthMethodTypeRadius:
+		// Get username from the params.
+		if username, ok := authMethod.Params["username"]; ok {
+			loginPath = fmt.Sprintf("auth/%s/login/%s", authMethod.MountPath, username)
+		} else {
+			return "", fmt.Errorf("failed to get 'username' from auth method params")
+		}
+	// This auth method requires a role for the login API path.
+	case VaultAuthMethodTypeOCI:
+		if role, ok := authMethod.Params["role"]; ok {
+			loginPath = fmt.Sprintf("auth/%s/login/%s", authMethod.MountPath, role)
+		} else {
+			return "", fmt.Errorf("failed to get 'role' from auth method params")
+		}
+	case VaultAuthMethodTypeToken:
+		return "", fmt.Errorf("'token' auth method is not supported via auth method configuration; " +
+			"please provide the token with the 'token' parameter in the CA configuration")
+	// The rest of the auth methods use auth/<auth method path> login API path.
+	case VaultAuthMethodTypeAliCloud,
+		VaultAuthMethodTypeAppRole,
+		VaultAuthMethodTypeAWS,
+		VaultAuthMethodTypeAzure,
+		VaultAuthMethodTypeCloudFoundry,
+		VaultAuthMethodTypeGitHub,
+		VaultAuthMethodTypeGCP,
+		VaultAuthMethodTypeJWT,
+		VaultAuthMethodTypeKerberos,
+		VaultAuthMethodTypeTLS:
+		loginPath = fmt.Sprintf("auth/%s/login", authMethod.MountPath)
+	default:
+		return "", fmt.Errorf("auth method %q is not supported", authMethod.Type)
+	}
+
+	return
+}

agent/connect/ca/provider_vault_test.go

@@ -18,6 +18,94 @@ import (
 	"github.com/hashicorp/consul/sdk/testutil/retry"
 )
 
+func TestVaultCAProvider_ParseVaultCAConfig(t *testing.T) {
+	cases := map[string]struct {
+		rawConfig map[string]interface{}
+		expConfig *structs.VaultCAProviderConfig
+		expError  string
+	}{
+		"no token and no auth method provided": {
+			rawConfig: map[string]interface{}{},
+			expError:  "must provide a Vault token or configure a Vault auth method",
+		},
+		"both token and auth method provided": {
+			rawConfig: map[string]interface{}{"Token": "test", "AuthMethod": map[string]interface{}{"Type": "test"}},
+			expError:  "only one of Vault token or Vault auth method can be provided, but not both",
+		},
+		"no root PKI path": {
+			rawConfig: map[string]interface{}{"Token": "test"},
+			expError:  "must provide a valid path to a root PKI backend",
+		},
+		"no root intermediate path": {
+			rawConfig: map[string]interface{}{"Token": "test", "RootPKIPath": "test"},
+			expError:  "must provide a valid path for the intermediate PKI backend",
+		},
+		"adds a slash to RootPKIPath and IntermediatePKIPath": {
+			rawConfig: map[string]interface{}{"Token": "test", "RootPKIPath": "test", "IntermediatePKIPath": "test"},
+			expConfig: &structs.VaultCAProviderConfig{
+				CommonCAProviderConfig: defaultCommonConfig(),
+				Token:                  "test",
+				RootPKIPath:            "test/",
+				IntermediatePKIPath:    "test/",
+			},
+		},
+	}
+
+	for name, c := range cases {
+		t.Run(name, func(t *testing.T) {
+			config, err := ParseVaultCAConfig(c.rawConfig)
+			if c.expError != "" {
+				require.EqualError(t, err, c.expError)
+			} else {
+				require.NoError(t, err)
+				require.Equal(t, c.expConfig, config)
+			}
+		})
+	}
+}
+
+func TestVaultCAProvider_configureVaultAuthMethod(t *testing.T) {
+	cases := map[string]struct {
+		expLoginPath string
+		params       map[string]interface{}
+		expError     string
+	}{
+		"alicloud":    {expLoginPath: "auth/alicloud/login"},
+		"approle":     {expLoginPath: "auth/approle/login"},
+		"aws":         {expLoginPath: "auth/aws/login"},
+		"azure":       {expLoginPath: "auth/azure/login"},
+		"cf":          {expLoginPath: "auth/cf/login"},
+		"github":      {expLoginPath: "auth/github/login"},
+		"gcp":         {expLoginPath: "auth/gcp/login"},
+		"jwt":         {expLoginPath: "auth/jwt/login"},
+		"kerberos":    {expLoginPath: "auth/kerberos/login"},
+		"kubernetes":  {expLoginPath: "auth/kubernetes/login", params: map[string]interface{}{"jwt": "fake"}},
+		"ldap":        {expLoginPath: "auth/ldap/login/foo", params: map[string]interface{}{"username": "foo"}},
+		"oci":         {expLoginPath: "auth/oci/login/foo", params: map[string]interface{}{"role": "foo"}},
+		"okta":        {expLoginPath: "auth/okta/login/foo", params: map[string]interface{}{"username": "foo"}},
+		"radius":      {expLoginPath: "auth/radius/login/foo", params: map[string]interface{}{"username": "foo"}},
+		"cert":        {expLoginPath: "auth/cert/login"},
+		"token":       {expError: "'token' auth method is not supported via auth method configuration; please provide the token with the 'token' parameter in the CA configuration"},
+		"userpass":    {expLoginPath: "auth/userpass/login/foo", params: map[string]interface{}{"username": "foo"}},
+		"unsupported": {expError: "auth method \"unsupported\" is not supported"},
+	}
+
+	for authMethodType, c := range cases {
+		t.Run(authMethodType, func(t *testing.T) {
+			loginPath, err := configureVaultAuthMethod(&structs.VaultAuthMethod{
+				Type:   authMethodType,
+				Params: c.params,
+			})
+			if c.expError == "" {
+				require.NoError(t, err)
+				require.Equal(t, c.expLoginPath, loginPath)
+			} else {
+				require.EqualError(t, err, c.expError)
+			}
+		})
+	}
+}
+
 func TestVaultCAProvider_VaultTLSConfig(t *testing.T) {
 	config := &structs.VaultCAProviderConfig{
 		CAFile:        "/capath/ca.pem",
@@ -507,6 +595,138 @@ func TestVaultProvider_Cleanup(t *testing.T) {
 	})
 }
 
+func TestVaultProvider_ConfigureWithAuthMethod(t *testing.T) {
+
+	SkipIfVaultNotPresent(t)
+
+	cases := []struct {
+		authMethodType          string
+		configureAuthMethodFunc func(t *testing.T, vaultClient *vaultapi.Client) map[string]interface{}
+	}{
+		{
+			authMethodType: "userpass",
+			configureAuthMethodFunc: func(t *testing.T, vaultClient *vaultapi.Client) map[string]interface{} {
+				_, err := vaultClient.Logical().Write("/auth/userpass/users/test",
+					map[string]interface{}{"password": "foo", "policies": "admins"})
+				require.NoError(t, err)
+				return map[string]interface{}{
+					"Type": "userpass",
+					"Params": map[string]interface{}{
+						"username": "test",
+						"password": "foo",
+					},
+				}
+			},
+		},
+		{
+			authMethodType: "approle",
+			configureAuthMethodFunc: func(t *testing.T, vaultClient *vaultapi.Client) map[string]interface{} {
+				_, err := vaultClient.Logical().Write("auth/approle/role/my-role", nil)
+				require.NoError(t, err)
+				resp, err := vaultClient.Logical().Read("auth/approle/role/my-role/role-id")
+				require.NoError(t, err)
+				roleID := resp.Data["role_id"]
+
+				resp, err = vaultClient.Logical().Write("auth/approle/role/my-role/secret-id", nil)
+				require.NoError(t, err)
+				secretID := resp.Data["secret_id"]
+
+				return map[string]interface{}{
+					"Type": "approle",
+					"Params": map[string]interface{}{
+						"role_id":   roleID,
+						"secret_id": secretID,
+					},
+				}
+			},
+		},
+	}
+
+	for _, c := range cases {
+		t.Run(c.authMethodType, func(t *testing.T) {
+			testVault := NewTestVaultServer(t)
+
+			err := testVault.Client().Sys().EnableAuthWithOptions(c.authMethodType, &vaultapi.EnableAuthOptions{Type: c.authMethodType})
+			require.NoError(t, err)
+
+			authMethodConf := c.configureAuthMethodFunc(t, testVault.Client())
+
+			conf := map[string]interface{}{
+				"Address":             testVault.Addr,
+				"RootPKIPath":         "pki-root/",
+				"IntermediatePKIPath": "pki-intermediate/",
+				"AuthMethod":          authMethodConf,
+			}
+
+			provider := NewVaultProvider(hclog.New(nil))
+
+			cfg := ProviderConfig{
+				ClusterID:  connect.TestClusterID,
+				Datacenter: "dc1",
+				IsPrimary:  true,
+				RawConfig:  conf,
+			}
+			t.Cleanup(provider.Stop)
+			err = provider.Configure(cfg)
+			require.NoError(t, err)
+			require.NotEmpty(t, provider.client.Token())
+		})
+	}
+}
+
+func TestVaultProvider_RotateAuthMethodToken(t *testing.T) {
+
+	SkipIfVaultNotPresent(t)
+
+	testVault := NewTestVaultServer(t)
+
+	err := testVault.Client().Sys().EnableAuthWithOptions("approle", &vaultapi.EnableAuthOptions{Type: "approle"})
+	require.NoError(t, err)
+
+	_, err = testVault.Client().Logical().Write("auth/approle/role/my-role",
+		map[string]interface{}{"token_ttl": "2s", "token_explicit_max_ttl": "2s"})
+	require.NoError(t, err)
+	resp, err := testVault.Client().Logical().Read("auth/approle/role/my-role/role-id")
+	require.NoError(t, err)
+	roleID := resp.Data["role_id"]
+
+	resp, err = testVault.Client().Logical().Write("auth/approle/role/my-role/secret-id", nil)
+	require.NoError(t, err)
+	secretID := resp.Data["secret_id"]
+
+	conf := map[string]interface{}{
+		"Address":             testVault.Addr,
+		"RootPKIPath":         "pki-root/",
+		"IntermediatePKIPath": "pki-intermediate/",
+		"AuthMethod": map[string]interface{}{
+			"Type": "approle",
+			"Params": map[string]interface{}{
+				"role_id":   roleID,
+				"secret_id": secretID,
+			},
+		},
+	}
+
+	provider := NewVaultProvider(hclog.New(nil))
+
+	cfg := ProviderConfig{
+		ClusterID:  connect.TestClusterID,
+		Datacenter: "dc1",
+		IsPrimary:  true,
+		RawConfig:  conf,
+	}
+	t.Cleanup(provider.Stop)
+	err = provider.Configure(cfg)
+	require.NoError(t, err)
+	token := provider.client.Token()
+	require.NotEmpty(t, token)
+
+	// Check that the token is rotated after max_ttl time has passed.
+	require.Eventually(t, func() bool {
+		return provider.client.Token() != token
+	}, 10*time.Second, 100*time.Millisecond)
+}
+
 func getIntermediateCertTTL(t *testing.T, caConf *structs.CAConfiguration) time.Duration {
 	t.Helper()
 
@@ -526,10 +746,6 @@ func getIntermediateCertTTL(t *testing.T, caConf *structs.CAConfiguration) time.
 	return dur
 }
 
-func testVaultProvider(t *testing.T) (*VaultProvider, *TestVaultServer) {
-	return testVaultProviderWithConfig(t, true, nil)
-}
-
 func testVaultProviderWithConfig(t *testing.T, isPrimary bool, rawConf map[string]interface{}) (*VaultProvider, *TestVaultServer) {
 	testVault, err := runTestVault(t)
 	if err != nil {
@@ -573,6 +789,7 @@ func createVaultProvider(t *testing.T, isPrimary bool, addr, token string, rawCo
 		cfg.Datacenter = "dc2"
 	}
 
+	t.Cleanup(provider.Stop)
 	require.NoError(t, provider.Configure(cfg))
 	if isPrimary {
 		require.NoError(t, provider.GenerateRoot())

agent/structs/connect_ca.go

@@ -481,6 +481,14 @@ type VaultCAProviderConfig struct {
 	KeyFile       string
 	TLSServerName string
 	TLSSkipVerify bool
+
+	AuthMethod *VaultAuthMethod `alias:"auth_method"`
+}
+
+type VaultAuthMethod struct {
+	Type      string
+	MountPath string `alias:"mount_path"`
+	Params    map[string]interface{}
 }
 
 type AWSCAProviderConfig struct {

website/content/docs/connect/ca/vault.mdx

@@ -88,13 +88,33 @@ The configuration options are listed below.
 - `Address` / `address` (`string: <required>`) - The address of the Vault
   server.
 
-- `Token` / `token` (`string: <required>`) - A token for accessing Vault.
+- `Token` / `token` (`string: ""`) - A token for accessing Vault.
   This is write-only and will not be exposed when reading the CA configuration.
   This token must have [proper privileges](#vault-acl-policies) for the PKI
   paths configured. In Consul 1.8.5 and later, if the token has the [renewable](https://www.vaultproject.io/api-docs/auth/token#renewable)
   flag set, Consul will attempt to renew its lease periodically after half the
   duration has expired.
 
+  !> **Warning:** You must either provide a token or configure an auth method below.
+
+- `AuthMethod` / `auth_method` (`map: nil`) - Vault auth method to use for logging in to Vault.
+  Please see [Vault Auth Methods](https://www.vaultproject.io/docs/auth) for more information
+  on how to configure individual auth methods. If auth method is provided, Consul will obtain a
+  a new token from Vault when the token can no longer be renewed.
+
+   - `Type`/ `type` (`string: ""`) - The type of Vault auth method.
+
+   - `MountPath`/ `mount_path` (`string: <AuthMethod.Type>`) - The mount path of the auth method.
+      If not provided the auth method type will be used as the mount path.
+
+   - `Params`/`params` (`map: nil`) - The parameters to configure the auth method. Please see
+    [Vault Auth Methods](https://www.vaultproject.io/docs/auth) for information on how to configure the
+    auth method you wish to use. If using the Kubernetes auth method,
+    Consul will read the service account token from the
+    default mount path `/var/run/secrets/kubernetes.io/serviceaccount/token` if the `jwt` parameter
+    is not provided.
+
+
 - `RootPKIPath` / `root_pki_path` (`string: <required>`) - The path to
   a PKI secrets engine for the root certificate. If the path does not
   exist, Consul will mount a new PKI secrets engine at the specified path with the