executor: privilege check USE command

executor/simple.go

@@ -26,6 +26,7 @@ import (
 	"github.com/pingcap/tidb/config"
 	"github.com/pingcap/tidb/domain"
 	"github.com/pingcap/tidb/infoschema"
+	"github.com/pingcap/tidb/privilege"
 	"github.com/pingcap/tidb/sessionctx"
 	"github.com/pingcap/tidb/sessionctx/variable"
 	"github.com/pingcap/tidb/util/chunk"
@@ -83,8 +84,25 @@ func (e *SimpleExec) Next(ctx context.Context, chk *chunk.Chunk) (err error) {
 	return errors.Trace(err)
 }
 
+func (e *SimpleExec) dbAccessDenied(dbname string) error {
+	user := e.ctx.GetSessionVars().User
+	u := user.Username
+	h := user.Hostname
+	if len(user.AuthUsername) > 0 && len(user.AuthHostname) > 0 {
+		u = user.AuthUsername
+		h = user.AuthHostname
+	}
+	return ErrDBaccessDenied.GenWithStackByArgs(u, h, dbname)
+}
+
 func (e *SimpleExec) executeUse(s *ast.UseStmt) error {
 	dbname := model.NewCIStr(s.DBName)
+
+	checker := privilege.GetPrivilegeManager(e.ctx)
+	if checker != nil && e.ctx.GetSessionVars().User != nil && !checker.DBIsVisible(fmt.Sprint(dbname)) {
+		return e.dbAccessDenied(dbname.O)
+	}
+
 	dbinfo, exists := e.is.SchemaByName(dbname)
 	if !exists {
 		return infoschema.ErrDatabaseNotExists.GenWithStackByArgs(dbname)

privilege/privileges/privileges_test.go

@@ -303,6 +303,31 @@ func (s *testPrivilegeSuite) TestCheckAuthenticate(c *C) {
 	c.Assert(se.Auth(&auth.UserIdentity{Username: "u4", Hostname: "localhost"}, nil, nil), IsFalse)
 }
 
+func (s *testPrivilegeSuite) TestUseDb(c *C) {
+
+	se := newSession(c, s.store, s.dbName)
+	// high privileged user
+	mustExec(c, se, "CREATE USER 'usesuper'")
+	mustExec(c, se, "CREATE USER 'usenobody'")
+	mustExec(c, se, "GRANT ALL ON *.* TO 'usesuper'")
+	mustExec(c, se, "FLUSH PRIVILEGES")
+	c.Assert(se.Auth(&auth.UserIdentity{Username: "usesuper", Hostname: "localhost", AuthUsername: "usesuper", AuthHostname: "%"}, nil, nil), IsTrue)
+	mustExec(c, se, "use mysql")
+	// low privileged user
+	c.Assert(se.Auth(&auth.UserIdentity{Username: "usenobody", Hostname: "localhost", AuthUsername: "usenobody", AuthHostname: "%"}, nil, nil), IsTrue)
+	_, err := se.Execute(context.Background(), "use mysql")
+	c.Assert(err, NotNil)
+
+	// try again after privilege granted
+	c.Assert(se.Auth(&auth.UserIdentity{Username: "usesuper", Hostname: "localhost", AuthUsername: "usesuper", AuthHostname: "%"}, nil, nil), IsTrue)
+	mustExec(c, se, "GRANT SELECT ON mysql.* TO 'usenobody'")
+	mustExec(c, se, "FLUSH PRIVILEGES")
+	c.Assert(se.Auth(&auth.UserIdentity{Username: "usenobody", Hostname: "localhost", AuthUsername: "usenobody", AuthHostname: "%"}, nil, nil), IsTrue)
+	_, err = se.Execute(context.Background(), "use mysql")
+	c.Assert(err, IsNil)
+
+}
+
 func (s *testPrivilegeSuite) TestInformationSchema(c *C) {
 
 	// This test tests no privilege check for INFORMATION_SCHEMA database.

server/server_test.go

@@ -619,34 +619,36 @@ func runTestShowProcessList(c *C) {
 func runTestAuth(c *C) {
 	runTests(c, nil, func(dbt *DBTest) {
 		dbt.mustExec(`CREATE USER 'authtest'@'%' IDENTIFIED BY '123';`)
+		dbt.mustExec(`GRANT ALL on test.* to 'authtest'`)
 		dbt.mustExec(`FLUSH PRIVILEGES;`)
 	})
 	runTests(c, func(config *mysql.Config) {
 		config.User = "authtest"
 		config.Passwd = "123"
 	}, func(dbt *DBTest) {
-		dbt.mustExec(`USE mysql;`)
+		dbt.mustExec(`USE information_schema;`)
 	})
 
 	db, err := sql.Open("mysql", getDSN(func(config *mysql.Config) {
 		config.User = "authtest"
 		config.Passwd = "456"
 	}))
 	c.Assert(err, IsNil)
-	_, err = db.Query("USE mysql;")
+	_, err = db.Query("USE information_schema;")
 	c.Assert(err, NotNil, Commentf("Wrong password should be failed"))
 	db.Close()
 
 	// Test login use IP that not exists in mysql.user.
 	runTests(c, nil, func(dbt *DBTest) {
 		dbt.mustExec(`CREATE USER 'authtest2'@'localhost' IDENTIFIED BY '123';`)
+		dbt.mustExec(`GRANT ALL on test.* to 'authtest2'@'localhost'`)
 		dbt.mustExec(`FLUSH PRIVILEGES;`)
 	})
 	runTests(c, func(config *mysql.Config) {
 		config.User = "authtest2"
 		config.Passwd = "123"
 	}, func(dbt *DBTest) {
-		dbt.mustExec(`USE mysql;`)
+		dbt.mustExec(`USE information_schema;`)
 	})
 }
 
@@ -683,7 +685,9 @@ func runTestIssue3680(c *C) {
 func runTestIssue3682(c *C) {
 	runTests(c, nil, func(dbt *DBTest) {
 		dbt.mustExec(`CREATE USER 'issue3682'@'%' IDENTIFIED BY '123';`)
-		dbt.mustExec(`FLUSH PRIVILEGES;`)
+		dbt.mustExec(`GRANT ALL on test.* to 'issue3682'`)
+		dbt.mustExec(`GRANT ALL on mysql.* to 'issue3682'`)
+		dbt.mustExec(`FLUSH PRIVILEGES`)
 	})
 	runTests(c, func(config *mysql.Config) {
 		config.User = "issue3682"