multi: Clear private data asap.

client/core/account.go

@@ -63,6 +63,7 @@ func (c *Core) AccountExport(pw []byte, host string) (*Account, error) {
 	if err != nil {
 		return nil, codedError(passwordErr, err)
 	}
+	defer crypter.Close()
 	host, err = addrHost(host)
 	if err != nil {
 		return nil, newError(addressParseErr, "error parsing address: %w", err)

client/core/core.go

@@ -1440,6 +1440,7 @@ func (c *Core) encryptionKey(pw []byte) (encrypt.Crypter, error) {
 	if err != nil {
 		return nil, fmt.Errorf("outer key deserialization error: %w", err)
 	}
+	defer outerCrypter.Close()
 	innerKey, err := outerCrypter.Decrypt(creds.EncInnerKey)
 	if err != nil {
 		return nil, fmt.Errorf("inner key decryption error: %w", err)
@@ -1711,6 +1712,7 @@ func (c *Core) CreateWallet(appPW, walletPW []byte, form *WalletForm) error {
 	if err != nil {
 		return err
 	}
+	defer crypter.Close()
 
 	walletDef, err := walletDefinition(assetID, form.Type)
 	if err != nil {
@@ -1821,6 +1823,7 @@ func (c *Core) createSeededWallet(assetID uint32, crypter encrypt.Crypter, form
 	if err != nil {
 		return nil, err
 	}
+	defer encode.ClearBytes(seed)
 
 	c.log.Infof("Initializing a built-in %s wallet", unbip(assetID))
 	if err = asset.CreateWallet(assetID, &asset.CreateWalletParams{
@@ -2052,6 +2055,7 @@ func (c *Core) OpenWallet(assetID uint32, appPW []byte) error {
 	if err != nil {
 		return err
 	}
+	defer crypter.Close()
 	wallet, err := c.connectedWallet(assetID)
 	if err != nil {
 		return fmt.Errorf("OpenWallet: wallet not found for %d -> %s: %w", assetID, unbip(assetID), err)
@@ -2173,6 +2177,7 @@ func (c *Core) ReconfigureWallet(appPW, newWalletPW []byte, form *WalletForm) er
 	if err != nil {
 		return newError(authErr, "ReconfigureWallet password error: %w", err)
 	}
+	defer crypter.Close()
 	assetID := form.AssetID
 	walletDef, err := walletDefinition(assetID, form.Type)
 	if err != nil {
@@ -2395,6 +2400,7 @@ func (c *Core) SetWalletPassword(appPW []byte, assetID uint32, newPW []byte) err
 	if err != nil {
 		return newError(authErr, "SetWalletPassword password error: %w", err)
 	}
+	defer crypter.Close()
 
 	// Check that the specified wallet exists.
 	c.walletMtx.Lock()
@@ -2685,6 +2691,7 @@ func (c *Core) DiscoverAccount(dexAddr string, appPW []byte, certI interface{})
 	if err != nil {
 		return nil, false, codedError(passwordErr, err)
 	}
+	defer crypter.Close()
 
 	var ready bool
 	dc, err := c.tempDexConnection(host, certI)
@@ -2781,6 +2788,7 @@ func (c *Core) Register(form *RegisterForm) (*RegisterResult, error) {
 	if err != nil {
 		return nil, codedError(passwordErr, err)
 	}
+	defer crypter.Close()
 	if form.Addr == "" {
 		return nil, newError(emptyHostErr, "no dex address specified")
 	}
@@ -3190,6 +3198,7 @@ func (c *Core) ExportSeed(pw []byte) ([]byte, error) {
 	if err != nil {
 		return nil, fmt.Errorf("ExportSeed password error: %w", err)
 	}
+	defer crypter.Close()
 
 	creds := c.creds()
 	if creds == nil {
@@ -3230,6 +3239,7 @@ func (c *Core) generateCredentials(pw, seed []byte) (encrypt.Crypter, *db.Primar
 	} else if len(seed) != seedLen {
 		return nil, nil, fmt.Errorf("invalid seed length %d. expected %d", len(seed), seedLen)
 	}
+	defer encode.ClearBytes(seed)
 
 	encSeed, err := innerCrypter.Encrypt(seed)
 	if err != nil {
@@ -3273,6 +3283,7 @@ func (c *Core) Login(pw []byte) (*LoginResult, error) {
 	if err != nil {
 		return nil, err
 	}
+	defer crypter.Close()
 
 	// Attempt to connect to and retrieve balance from all known wallets. It is
 	// not an error if we can't connect, unless we need the wallet for active
@@ -3886,6 +3897,7 @@ func (c *Core) Withdraw(pw []byte, assetID uint32, value uint64, address string)
 	if err != nil {
 		return nil, fmt.Errorf("Withdraw password error: %w", err)
 	}
+	defer crypter.Close()
 	if value == 0 {
 		return nil, fmt.Errorf("cannot withdraw zero %s", unbip(assetID))
 	}
@@ -4046,6 +4058,7 @@ func (c *Core) Trade(pw []byte, form *TradeForm) (*Order, error) {
 	if err != nil {
 		return nil, fmt.Errorf("Trade password error: %w", err)
 	}
+	defer crypter.Close()
 	dc, err := c.connectedDEX(form.Host)
 	if err != nil {
 		return nil, err

client/core/types.go

@@ -633,6 +633,7 @@ func (a *dexAccount) setupCryptoV2(creds *db.PrimaryCredentials, crypter encrypt
 	if err != nil {
 		return fmt.Errorf("seed decryption error: %w", err)
 	}
+	defer encode.ClearBytes(seed)
 
 	dexPkB := a.dexPubKey.SerializeCompressed()
 	// And because I'm neurotic.

client/rpcserver/handlers.go

@@ -127,9 +127,7 @@ func handleInit(s *RPCServer, params *RawParams) *msgjson.ResponsePayload {
 	}
 	defer func() {
 		appPass.Clear()
-		if len(seed) > 0 {
-			seed.Clear()
-		}
+		seed.Clear()
 	}()
 	if err := s.core.InitializeClient(appPass, seed); err != nil {
 		errMsg := fmt.Sprintf("unable to initialize client: %v", err)
@@ -206,9 +204,9 @@ func handleOpenWallet(s *RPCServer, params *RawParams) *msgjson.ResponsePayload
 	if err != nil {
 		return usage(openWalletRoute, err)
 	}
+	defer form.appPass.Clear()
 
 	err = s.core.OpenWallet(form.assetID, form.appPass)
-	form.appPass.Clear() // AppPass not needed after this, clear
 	if err != nil {
 		errMsg := fmt.Sprintf("error unlocking %s wallet: %v",
 			dex.BipIDSymbol(form.assetID), err)
@@ -609,19 +607,14 @@ func handleAppSeed(s *RPCServer, params *RawParams) *msgjson.ResponsePayload {
 	}
 	defer appPass.Clear()
 	seed, err := s.core.ExportSeed(appPass)
+	defer encode.ClearBytes(seed)
 	if err != nil {
 		errMsg := fmt.Sprintf("unable to retrieve app seed: %v", err)
 		resErr := msgjson.NewError(msgjson.RPCExportSeedError, errMsg)
 		return createResponse(appSeedRoute, nil, resErr)
 	}
 	// Zero seed and hex representation after use.
 	seedHex := fmt.Sprintf("%x", seed[:])
-	defer func() {
-		for i := range seed {
-			seed[i] = 0
-		}
-		seedHex = ""
-	}()
 
 	return createResponse(appSeedRoute, seedHex, nil)
 }

client/webserver/api.go

@@ -17,9 +17,12 @@ import (
 	"decred.org/dcrdex/dex/encode"
 )
 
+var zero = encode.ClearBytes
+
 // apiDiscoverAccount is the handler for the '/discoveracct' API request.
 func (s *WebServer) apiDiscoverAccount(w http.ResponseWriter, r *http.Request) {
 	form := new(registrationForm)
+	defer form.Password.Clear()
 	if !readPost(w, r, form) {
 		return
 	}
@@ -29,6 +32,7 @@ func (s *WebServer) apiDiscoverAccount(w http.ResponseWriter, r *http.Request) {
 		s.writeAPIError(w, fmt.Errorf("password error: %w", err))
 		return
 	}
+	defer zero(pass)
 	exchangeInfo, paid, err := s.core.DiscoverAccount(form.Addr, pass, cert)
 	if err != nil {
 		s.writeAPIError(w, err)
@@ -111,6 +115,7 @@ func (s *WebServer) apiRegister(w http.ResponseWriter, r *http.Request) {
 		s.writeAPIError(w, fmt.Errorf("password error: %w", err))
 		return
 	}
+	defer zero(pass)
 	_, err = s.core.Register(&core.RegisterForm{
 		Addr:    reg.Addr,
 		Cert:    []byte(reg.Cert),
@@ -131,10 +136,8 @@ func (s *WebServer) apiRegister(w http.ResponseWriter, r *http.Request) {
 // apiNewWallet is the handler for the '/newwallet' API request.
 func (s *WebServer) apiNewWallet(w http.ResponseWriter, r *http.Request) {
 	form := new(newWalletForm)
-	defer func() {
-		form.AppPW.Clear()
-		form.Pass.Clear()
-	}()
+	defer form.AppPW.Clear()
+	defer form.Pass.Clear()
 	if !readPost(w, r, form) {
 		return
 	}
@@ -148,6 +151,7 @@ func (s *WebServer) apiNewWallet(w http.ResponseWriter, r *http.Request) {
 		s.writeAPIError(w, fmt.Errorf("password error: %w", err))
 		return
 	}
+	defer zero(pass)
 	// Wallet does not exist yet. Try to create it.
 	err = s.core.CreateWallet(pass, form.Pass, &core.WalletForm{
 		AssetID: form.AssetID,
@@ -206,6 +210,7 @@ func (s *WebServer) apiOpenWallet(w http.ResponseWriter, r *http.Request) {
 		s.writeAPIError(w, fmt.Errorf("password error: %w", err))
 		return
 	}
+	defer zero(pass)
 	err = s.core.OpenWallet(form.AssetID, pass)
 	if err != nil {
 		s.writeAPIError(w, fmt.Errorf("error unlocking %s wallet: %w", unbip(form.AssetID), err))
@@ -275,6 +280,7 @@ func (s *WebServer) apiTrade(w http.ResponseWriter, r *http.Request) {
 		s.writeAPIError(w, fmt.Errorf("password error: %w", err))
 		return
 	}
+	defer zero(pass)
 	ord, err := s.core.Trade(pass, form.Order)
 	if err != nil {
 		s.writeAPIError(w, fmt.Errorf("error placing order: %w", err))
@@ -304,6 +310,7 @@ func (s *WebServer) apiAccountExport(w http.ResponseWriter, r *http.Request) {
 		s.writeAPIError(w, fmt.Errorf("password error: %w", err))
 		return
 	}
+	defer zero(pass)
 	account, err := s.core.AccountExport(pass, form.Host)
 	if err != nil {
 		s.writeAPIError(w, fmt.Errorf("error exporting account: %w", err))
@@ -325,6 +332,7 @@ func (s *WebServer) apiExportSeed(w http.ResponseWriter, r *http.Request) {
 	form := &struct {
 		Pass encode.PassBytes `json:"pass"`
 	}{}
+	defer form.Pass.Clear()
 	if !readPost(w, r, form) {
 		return
 	}
@@ -334,6 +342,7 @@ func (s *WebServer) apiExportSeed(w http.ResponseWriter, r *http.Request) {
 		s.writeAPIError(w, fmt.Errorf("error exporting seed: %w", err))
 		return
 	}
+	defer zero(seed)
 	writeJSON(w, &struct {
 		OK   bool      `json:"ok"`
 		Seed dex.Bytes `json:"seed"`
@@ -356,6 +365,7 @@ func (s *WebServer) apiAccountImport(w http.ResponseWriter, r *http.Request) {
 		s.writeAPIError(w, fmt.Errorf("password error: %w", err))
 		return
 	}
+	defer zero(pass)
 	err = s.core.AccountImport(pass, form.Account)
 	if err != nil {
 		s.writeAPIError(w, fmt.Errorf("error importing account: %w", err))
@@ -375,6 +385,7 @@ func (s *WebServer) apiAccountDisable(w http.ResponseWriter, r *http.Request) {
 
 	// Disable account.
 	err := s.core.AccountDisable(form.Pass, form.Host)
+	zero(form.Pass)
 	if err != nil {
 		s.writeAPIError(w, fmt.Errorf("error disabling account: %w", err))
 		return
@@ -395,6 +406,7 @@ func (s *WebServer) apiCancel(w http.ResponseWriter, r *http.Request) {
 		s.writeAPIError(w, fmt.Errorf("password error: %w", err))
 		return
 	}
+	defer zero(pass)
 	err = s.core.Cancel(pass, form.OrderID)
 	if err != nil {
 		s.writeAPIError(w, fmt.Errorf("error cancelling order %s: %w", form.OrderID, err))
@@ -424,6 +436,7 @@ func (s *WebServer) apiCloseWallet(w http.ResponseWriter, r *http.Request) {
 func (s *WebServer) apiInit(w http.ResponseWriter, r *http.Request) {
 	init := new(initForm)
 	defer init.Pass.Clear()
+	defer zero(init.Seed)
 	if !readPost(w, r, init) {
 		return
 	}
@@ -646,6 +659,7 @@ func (s *WebServer) apiChangeAppPass(w http.ResponseWriter, r *http.Request) {
 			log.Errorf("unable to cache password: %w", err)
 			clearCookie(pwKeyCK, w)
 		} else {
+			zero(key)
 			setCookie(pwKeyCK, hex.EncodeToString(key), w)
 		}
 	}
@@ -675,6 +689,7 @@ func (s *WebServer) apiReconfig(w http.ResponseWriter, r *http.Request) {
 		s.writeAPIError(w, fmt.Errorf("password error: %w", err))
 		return
 	}
+	defer zero(pass)
 	// Update wallet settings.
 	err = s.core.ReconfigureWallet(pass, form.NewWalletPW, &core.WalletForm{
 		AssetID: form.AssetID,
@@ -790,9 +805,11 @@ func (s *WebServer) apiPreOrder(w http.ResponseWriter, r *http.Request) {
 	writeJSON(w, resp, s.indent)
 }
 
-// apiActuallyLogin logs the user in.
+// apiActuallyLogin logs the user in. login form private data is expected to be
+// cleared by the caller.
 func (s *WebServer) actuallyLogin(w http.ResponseWriter, r *http.Request, login *loginForm) {
 	pass, err := s.resolvePass(login.Pass, r)
+	defer zero(pass)
 	if err != nil {
 		s.writeAPIError(w, fmt.Errorf("password error: %w", err))
 		return
@@ -814,6 +831,7 @@ func (s *WebServer) actuallyLogin(w http.ResponseWriter, r *http.Request, login
 				return
 			}
 			setCookie(pwKeyCK, hex.EncodeToString(key), w)
+			zero(key)
 		} else {
 			// If dexc was shutdown and restarted, the old pw key cookie might
 			// need to be cleared.

client/webserver/webserver.go

@@ -481,6 +481,7 @@ func (s *WebServer) authorize() string {
 	b := make([]byte, 32)
 	rand.Read(b)
 	token := hex.EncodeToString(b)
+	zero(b)
 	s.authMtx.Lock()
 	s.authTokens[token] = true
 	s.authMtx.Unlock()
@@ -589,6 +590,7 @@ func (s *WebServer) getCachedPasswordUsingRequest(r *http.Request) ([]byte, erro
 func (s *WebServer) cacheAppPassword(appPW []byte, authToken string) ([]byte, error) {
 	key := encode.RandomBytes(16)
 	crypter := encrypt.NewCrypter(key)
+	defer crypter.Close()
 	encryptedPass, err := crypter.Encrypt(appPW)
 	if err != nil {
 		return nil, fmt.Errorf("error encrypting password: %v", err)