Add support for IAM Auth for Google CloudSQL DBs

changelog/22445.txt

@@ -0,0 +1,3 @@
+```release-note:feature
+**GCP IAM Support**: Adds support for IAM-based authentication to MySQL and PostgreSQL backends using Google Cloud SQL.
+```

go.mod

@@ -23,6 +23,7 @@ replace github.com/hashicorp/vault/api/auth/userpass => ./api/auth/userpass
 replace github.com/hashicorp/vault/sdk => ./sdk
 
 require (
+	cloud.google.com/go/cloudsqlconn v1.4.3
 	cloud.google.com/go/monitoring v1.15.1
 	cloud.google.com/go/spanner v1.47.0
 	cloud.google.com/go/storage v1.30.1
@@ -50,7 +51,7 @@ require (
 	github.com/client9/misspell v0.3.4
 	github.com/cockroachdb/cockroach-go v0.0.0-20181001143604-e0a95dfd547c
 	github.com/coreos/go-systemd v0.0.0-20191104093116-d3cd4ed1dbcf
-	github.com/denisenkom/go-mssqldb v0.12.2
+	github.com/denisenkom/go-mssqldb v0.12.3
 	github.com/duosecurity/duo_api_golang v0.0.0-20190308151101-6c680f768e74
 	github.com/dustin/go-humanize v1.0.1
 	github.com/fatih/color v1.15.0
@@ -62,7 +63,7 @@ require (
 	github.com/go-git/go-git/v5 v5.7.0
 	github.com/go-jose/go-jose/v3 v3.0.0
 	github.com/go-ldap/ldap/v3 v3.4.4
-	github.com/go-sql-driver/mysql v1.6.0
+	github.com/go-sql-driver/mysql v1.7.1
 	github.com/go-test/deep v1.1.0
 	github.com/go-zookeeper/zk v1.0.3
 	github.com/gocql/gocql v1.0.0
@@ -217,7 +218,7 @@ require (
 	golang.org/x/sys v0.12.0
 	golang.org/x/term v0.12.0
 	golang.org/x/text v0.13.0
-	golang.org/x/tools v0.8.0
+	golang.org/x/tools v0.9.1
 	google.golang.org/api v0.138.0
 	google.golang.org/grpc v1.57.0
 	google.golang.org/grpc/cmd/protoc-gen-go-grpc v1.1.0
@@ -361,7 +362,7 @@ require (
 	github.com/gofrs/uuid v4.3.0+incompatible // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/golang-jwt/jwt/v5 v5.0.0 // indirect
-	github.com/golang-sql/civil v0.0.0-20190719163853-cb61b32ac6fe // indirect
+	github.com/golang-sql/civil v0.0.0-20220223132316-b832511892a9 // indirect
 	github.com/golang-sql/sqlexp v0.1.0 // indirect
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
 	github.com/golang/snappy v0.0.4 // indirect

plugins/database/mysql/connection_producer.go

@@ -13,6 +13,7 @@ import (
 	"sync"
 	"time"
 
+	cloudmysql "cloud.google.com/go/cloudsqlconn/mysql/mysql"
 	"github.com/go-sql-driver/mysql"
 	"github.com/hashicorp/go-secure-stdlib/parseutil"
 	"github.com/hashicorp/go-uuid"
@@ -21,6 +22,11 @@ import (
 	"github.com/mitchellh/mapstructure"
 )
 
+const (
+	cloudSQLMySQL = "cloudsql-mysql"
+	driverMySQL   = "mysql"
+)
+
 // mySQLConnectionProducer implements ConnectionProducer and provides a generic producer for most sql databases
 type mySQLConnectionProducer struct {
 	ConnectionURL            string      `json:"connection_url"          mapstructure:"connection_url"          structs:"connection_url"`
@@ -29,6 +35,8 @@ type mySQLConnectionProducer struct {
 	MaxConnectionLifetimeRaw interface{} `json:"max_connection_lifetime" mapstructure:"max_connection_lifetime" structs:"max_connection_lifetime"`
 	Username                 string      `json:"username" mapstructure:"username" structs:"username"`
 	Password                 string      `json:"password" mapstructure:"password" structs:"password"`
+	AuthType                 string      `json:"auth_type" mapstructure:"auth_type" structs:"auth_type"`
+	ServiceAccountJSON       string      `json:"service_account_json" mapstructure:"service_account_json" structs:"service_account_json"`
 
 	TLSCertificateKeyData []byte `json:"tls_certificate_key" mapstructure:"tls_certificate_key" structs:"-"`
 	TLSCAData             []byte `json:"tls_ca"              mapstructure:"tls_ca"              structs:"-"`
@@ -38,6 +46,10 @@ type mySQLConnectionProducer struct {
 	// tlsConfigName is a globally unique name that references the TLS config for this instance in the mysql driver
 	tlsConfigName string
 
+	// cloudDriverName is a globally unique name that references the cloud dialer config for this instance of the driver
+	cloudDriverName    string
+	cloudDialerCleanup func() error
+
 	RawConfig             map[string]interface{}
 	maxConnectionLifetime time.Duration
 	Initialized           bool
@@ -110,6 +122,32 @@ func (c *mySQLConnectionProducer) Init(ctx context.Context, conf map[string]inte
 		mysql.RegisterTLSConfig(c.tlsConfigName, tlsConfig)
 	}
 
+	// validate auth_type if provided
+	authType := c.AuthType
+	if authType != "" {
+		if ok := connutil.ValidateAuthType(authType); !ok {
+			return nil, fmt.Errorf("invalid auth_type %s provided", authType)
+		}
+	}
+
+	if c.AuthType == connutil.AuthTypeGCPIAM {
+		c.cloudDriverName, err = uuid.GenerateUUID()
+		if err != nil {
+			return nil, fmt.Errorf("unable to generate UUID for IAM configuration: %w", err)
+		}
+
+		// for _most_ sql databases, the driver itself contains no state. In the case of google's cloudsql drivers,
+		// however, the driver might store a credentials file, in which case the state stored by the driver is in
+		// fact critical to the proper function of the connection. So it needs to be registered here inside the
+		// ConnectionProducer init.
+		dialerCleanup, err := registerDriverMySQL(c.cloudDriverName, c.ServiceAccountJSON)
+		if err != nil {
+			return nil, err
+		}
+
+		c.cloudDialerCleanup = dialerCleanup
+	}
+
 	// Set initialized to true at this point since all fields are set,
 	// and the connection can be established at a later time.
 	c.Initialized = true
@@ -140,14 +178,33 @@ func (c *mySQLConnectionProducer) Connection(ctx context.Context) (interface{},
 		// If the ping was unsuccessful, close it and ignore errors as we'll be
 		// reestablishing anyways
 		c.db.Close()
+
+		// if IAM authentication was enabled
+		// ensure open dialer is also closed
+		if c.AuthType == connutil.AuthTypeGCPIAM {
+			if c.cloudDialerCleanup != nil {
+				c.cloudDialerCleanup()
+			}
+		}
+
+	}
+
+	driverName := driverMySQL
+	if c.cloudDriverName != "" {
+		driverName = c.cloudDriverName
 	}
 
 	connURL, err := c.addTLStoDSN()
 	if err != nil {
 		return nil, err
 	}
 
-	c.db, err = sql.Open("mysql", connURL)
+	cloudURL, err := c.rewriteProtocolForGCP(connURL)
+	if err != nil {
+		return nil, err
+	}
+
+	c.db, err = sql.Open(driverName, cloudURL)
 	if err != nil {
 		return nil, err
 	}
@@ -174,6 +231,13 @@ func (c *mySQLConnectionProducer) Close() error {
 	defer c.Unlock()
 
 	if c.db != nil {
+		// if auth_type is IAM, ensure cleanup
+		// of cloudSQL resources
+		if c.AuthType == connutil.AuthTypeGCPIAM {
+			if c.cloudDialerCleanup != nil {
+				c.cloudDialerCleanup()
+			}
+		}
 		c.db.Close()
 	}
 
@@ -230,3 +294,38 @@ func (c *mySQLConnectionProducer) addTLStoDSN() (connURL string, err error) {
 	connURL = config.FormatDSN()
 	return connURL, nil
 }
+
+// rewriteProtocolForGCP rewrites the protocol in the DSN to contain the protocol name associated
+// with the dialer and therefore driver associated with the provided cloudsqlconn.DialerOpts.
+// As a safety/sanity check, it will only do this for protocol "cloudsql-mysql", the name GCP uses in its documentation.
+//
+// For example, it will rewrite the dsn "user@cloudsql-mysql(zone:region:instance)/ to
+// "user@the-uuid-generated(zone:region:instance)/
+func (c *mySQLConnectionProducer) rewriteProtocolForGCP(inDSN string) (string, error) {
+	if c.cloudDriverName == "" {
+		// unchanged if not cloud
+		return inDSN, nil
+	}
+
+	config, err := mysql.ParseDSN(inDSN)
+	if err != nil {
+		return "", fmt.Errorf("unable to parse connectionURL: %s", err)
+	}
+
+	if config.Net != cloudSQLMySQL {
+		return "", fmt.Errorf("didn't update net name because it wasn't what we expected as a placeholder: %s", config.Net)
+	}
+
+	config.Net = c.cloudDriverName
+
+	return config.FormatDSN(), nil
+}
+
+func registerDriverMySQL(driverName, credentials string) (cleanup func() error, err error) {
+	opts, err := connutil.GetCloudSQLAuthOptions(credentials)
+	if err != nil {
+		return nil, err
+	}
+
+	return cloudmysql.RegisterDriver(driverName, opts...)
+}

plugins/database/mysql/mysql_test.go

@@ -7,18 +7,21 @@ import (
 	"context"
 	"database/sql"
 	"fmt"
+	"os"
 	"strings"
 	"testing"
 	"time"
 
 	stdmysql "github.com/go-sql-driver/mysql"
 	"github.com/hashicorp/go-secure-stdlib/strutil"
+	"github.com/stretchr/testify/require"
+
 	mysqlhelper "github.com/hashicorp/vault/helper/testhelpers/mysql"
-	dbplugin "github.com/hashicorp/vault/sdk/database/dbplugin/v5"
+	"github.com/hashicorp/vault/sdk/database/dbplugin/v5"
 	dbtesting "github.com/hashicorp/vault/sdk/database/dbplugin/v5/testing"
+	"github.com/hashicorp/vault/sdk/database/helper/connutil"
 	"github.com/hashicorp/vault/sdk/database/helper/credsutil"
 	"github.com/hashicorp/vault/sdk/database/helper/dbutil"
-	"github.com/stretchr/testify/require"
 )
 
 var _ dbplugin.Database = (*MySQL)(nil)
@@ -44,6 +47,79 @@ func TestMySQL_Initialize(t *testing.T) {
 	}
 }
 
+// TestMySQL_Initialize_CloudGCP validates the proper initialization of a MySQL backend pointing
+// to a GCP CloudSQL MySQL instance. This expects some external setup (exact TBD)
+func TestMySQL_Initialize_CloudGCP(t *testing.T) {
+	envConnURL := "CONNECTION_URL"
+	connURL := os.Getenv(envConnURL)
+	if connURL == "" {
+		t.Skipf("env var %s not set, skipping test", envConnURL)
+	}
+
+	credStr := dbtesting.GetGCPTestCredentials(t)
+
+	tests := map[string]struct {
+		req           dbplugin.InitializeRequest
+		wantErr       bool
+		expectedError string
+	}{
+		"empty auth type": {
+			req: dbplugin.InitializeRequest{
+				Config: map[string]interface{}{
+					"connection_url": connURL,
+					"auth_type":      "",
+				},
+			},
+		},
+		"invalid auth type": {
+			req: dbplugin.InitializeRequest{
+				Config: map[string]interface{}{
+					"connection_url": connURL,
+					"auth_type":      "invalid",
+				},
+			},
+			wantErr:       true,
+			expectedError: "invalid auth_type",
+		},
+		"JSON credentials": {
+			req: dbplugin.InitializeRequest{
+				Config: map[string]interface{}{
+					"connection_url":       connURL,
+					"auth_type":            connutil.AuthTypeGCPIAM,
+					"service_account_json": credStr,
+				},
+				VerifyConnection: true,
+			},
+		},
+	}
+
+	for n, tc := range tests {
+		t.Run(n, func(t *testing.T) {
+			db := newMySQL(DefaultUserNameTemplate)
+			defer dbtesting.AssertClose(t, db)
+			_, err := db.Initialize(context.Background(), tc.req)
+
+			if tc.wantErr {
+				if err == nil {
+					t.Fatalf("expected error but received nil")
+				}
+
+				if !strings.Contains(err.Error(), tc.expectedError) {
+					t.Fatalf("expected error %s, got %s", tc.expectedError, err.Error())
+				}
+			} else {
+				if err != nil {
+					t.Fatalf("expected no error, received %s", err)
+				}
+
+				if !db.Initialized {
+					t.Fatal("Database should be initialized")
+				}
+			}
+		})
+	}
+}
+
 func testInitialize(t *testing.T, rootPassword string) {
 	cleanup, connURL := mysqlhelper.PrepareTestContainer(t, false, rootPassword)
 	defer cleanup()