[VAULT-3379] Add support for contained DBs in MSSQL root rotation and…

… lease revocation (#12839)

changelog/12839.txt

@@ -0,0 +1,3 @@
+```release-note:improvement
+secrets/database: Update MSSQL dependency github.com/denisenkom/go-mssqldb to v0.11.0 and include support for contained databases in MSSQL plugin
+```

go.mod

@@ -37,7 +37,7 @@ require (
 	github.com/containerd/containerd v1.4.3 // indirect
 	github.com/coreos/go-semver v0.3.0
 	github.com/coreos/go-systemd v0.0.0-20191104093116-d3cd4ed1dbcf
-	github.com/denisenkom/go-mssqldb v0.0.0-20200428022330-06a60b6afbbc
+	github.com/denisenkom/go-mssqldb v0.11.0
 	github.com/docker/distribution v2.7.1+incompatible // indirect
 	github.com/docker/docker v17.12.0-ce-rc1.0.20200309214505-aa6a9891b09c+incompatible
 	github.com/docker/go-connections v0.4.0

go.sum

@@ -304,6 +304,8 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/denisenkom/go-mssqldb v0.0.0-20200428022330-06a60b6afbbc h1:VRRKCwnzqk8QCaRC4os14xoKDdbHqqlJtJA0oc1ZAjg=
 github.com/denisenkom/go-mssqldb v0.0.0-20200428022330-06a60b6afbbc/go.mod h1:xbL0rPBG9cCiLr28tMa8zpbdarY27NDyej4t/EjAShU=
+github.com/denisenkom/go-mssqldb v0.11.0 h1:9rHa233rhdOyrz2GcP9NM+gi2psgJZ4GWDpL/7ND8HI=
+github.com/denisenkom/go-mssqldb v0.11.0/go.mod h1:xbL0rPBG9cCiLr28tMa8zpbdarY27NDyej4t/EjAShU=
 github.com/denverdino/aliyungo v0.0.0-20170926055100-d3308649c661 h1:lrWnAyy/F72MbxIxFUzKmcMCdt9Oi8RzpAxzTNQHD7o=
 github.com/denverdino/aliyungo v0.0.0-20170926055100-d3308649c661/go.mod h1:dV8lFg6daOBZbT6/BDGIz6Y3WFGn8juu6G+CQ6LHtl0=
 github.com/dgrijalva/jwt-go v3.2.0+incompatible/go.mod h1:E3ru+11k8xSBh+hMPgOLZmtrrCbhqsmaPHjLKYnJCaQ=

plugins/database/mssql/mssql.go

@@ -5,6 +5,7 @@ import (
 	"database/sql"
 	"errors"
 	"fmt"
+	"strconv"
 	"strings"
 
 	_ "github.com/denisenkom/go-mssqldb"
@@ -30,6 +31,9 @@ type MSSQL struct {
 	*connutil.SQLConnectionProducer
 
 	usernameProducer template.StringTemplate
+
+	// A flag to let us know to skip cross DB queries and server login checks
+	containedDB bool
 }
 
 func New() (interface{}, error) {
@@ -94,6 +98,20 @@ func (m *MSSQL) Initialize(ctx context.Context, req dbplugin.InitializeRequest)
 		return dbplugin.InitializeResponse{}, fmt.Errorf("invalid username template - did you reference a field that isn't available? : %w", err)
 	}
 
+	containedDB := false
+	containedDBRaw, err := strutil.GetString(req.Config, "contained_db")
+	if err != nil {
+		return dbplugin.InitializeResponse{}, fmt.Errorf("failed to retrieve contained_db: %w", err)
+	}
+	if containedDBRaw != "" {
+		containedDB, err = strconv.ParseBool(containedDBRaw)
+		if err != nil {
+			return dbplugin.InitializeResponse{}, fmt.Errorf("parsing error: incorrect boolean operator provided for contained_db: %w", err)
+		}
+	}
+
+	m.containedDB = containedDB
+
 	resp := dbplugin.InitializeResponse{
 		Config: newConf,
 	}
@@ -201,6 +219,19 @@ func (m *MSSQL) revokeUserDefault(ctx context.Context, username string) error {
 		return err
 	}
 
+	// Check if DB is contained
+	if m.containedDB {
+		revokeStmt, err := db.PrepareContext(ctx, fmt.Sprintf("DROP USER IF EXISTS [%s]", username))
+		if err != nil {
+			return err
+		}
+		defer revokeStmt.Close()
+		if _, err := revokeStmt.ExecContext(ctx); err != nil {
+			return err
+		}
+		return nil
+	}
+
 	// First disable server login
 	disableStmt, err := db.PrepareContext(ctx, fmt.Sprintf("ALTER LOGIN [%s] DISABLE;", username))
 	if err != nil {
@@ -311,7 +342,7 @@ func (m *MSSQL) UpdateUser(ctx context.Context, req dbplugin.UpdateUserRequest)
 
 func (m *MSSQL) updateUserPass(ctx context.Context, username string, changePass *dbplugin.ChangePassword) error {
 	stmts := changePass.Statements.Commands
-	if len(stmts) == 0 {
+	if len(stmts) == 0 && !m.containedDB {
 		stmts = []string{alterLoginSQL}
 	}
 
@@ -329,12 +360,16 @@ func (m *MSSQL) updateUserPass(ctx context.Context, username string, changePass
 		return err
 	}
 
-	var exists bool
+	// Since contained DB users do not have server logins, we
+	// only query for a login if DB is not a contained DB
+	if !m.containedDB {
+		var exists bool
 
-	err = db.QueryRowContext(ctx, "SELECT 1 FROM master.sys.server_principals where name = N'$1'", username).Scan(&exists)
+		err = db.QueryRowContext(ctx, "SELECT 1 FROM master.sys.server_principals where name = N'$1'", username).Scan(&exists)
 
-	if err != nil && err != sql.ErrNoRows {
-		return err
+		if err != nil && err != sql.ErrNoRows {
+			return err
+		}
 	}
 
 	tx, err := db.BeginTx(ctx, nil)

plugins/database/mssql/mssql_test.go

@@ -42,6 +42,15 @@ func TestInitialize(t *testing.T) {
 				VerifyConnection: true,
 			},
 		},
+		"contained_db set": {
+			dbplugin.InitializeRequest{
+				Config: map[string]interface{}{
+					"connection_url": connURL,
+					"contained_db":   "true",
+				},
+				VerifyConnection: true,
+			},
+		},
 	}
 
 	for name, test := range tests {
@@ -265,6 +274,26 @@ func TestUpdateUser_password(t *testing.T) {
 			}
 
 			assertCredsExist(t, connURL, dbUser, test.expectedPassword)
+
+			// Delete user at the end of each test
+			deleteReq := dbplugin.DeleteUserRequest{
+				Username: dbUser,
+			}
+
+			ctx, cancel = context.WithTimeout(context.Background(), 5*time.Second)
+			defer cancel()
+			deleteResp, err := db.DeleteUser(ctx, deleteReq)
+			if err != nil {
+				t.Fatalf("Failed to delete user: %s", err)
+			}
+
+			// Protect against future fields that aren't specified
+			expectedDeleteResp := dbplugin.DeleteUserResponse{}
+			if !reflect.DeepEqual(deleteResp, expectedDeleteResp) {
+				t.Fatalf("Fields missing from expected response: Actual: %#v", deleteResp)
+			}
+
+			assertCredsDoNotExist(t, connURL, dbUser, initPassword)
 		})
 	}
 }