forked from quic-go/quic-go
/
crypto_setup_client.go
542 lines (462 loc) · 13.5 KB
/
crypto_setup_client.go
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package handshake
import (
"bytes"
"crypto/rand"
"crypto/tls"
"encoding/binary"
"errors"
"fmt"
"io"
"sync"
"time"
"github.com/lucas-clemente/quic-go/internal/crypto"
"github.com/lucas-clemente/quic-go/internal/protocol"
"github.com/lucas-clemente/quic-go/internal/utils"
"github.com/lucas-clemente/quic-go/qerr"
)
type cryptoSetupClient struct {
mutex sync.RWMutex
hostname string
connID protocol.ConnectionID
version protocol.VersionNumber
initialVersion protocol.VersionNumber
negotiatedVersions []protocol.VersionNumber
cryptoStream io.ReadWriter
serverConfig *serverConfigClient
stk []byte
sno []byte
nonc []byte
proof []byte
chloForSignature []byte
lastSentCHLO []byte
certManager crypto.CertManager
divNonceChan chan struct{}
diversificationNonce []byte
clientHelloCounter int
serverVerified bool // has the certificate chain and the proof already been verified
keyDerivation QuicCryptoKeyDerivationFunction
receivedSecurePacket bool
nullAEAD crypto.AEAD
secureAEAD crypto.AEAD
forwardSecureAEAD crypto.AEAD
paramsChan chan<- TransportParameters
handshakeEvent chan<- struct{}
params *TransportParameters
logger utils.Logger
}
var _ CryptoSetup = &cryptoSetupClient{}
var (
errNoObitForClientNonce = errors.New("CryptoSetup BUG: No OBIT for client nonce available")
errClientNonceAlreadyExists = errors.New("CryptoSetup BUG: A client nonce was already generated")
errConflictingDiversificationNonces = errors.New("Received two different diversification nonces")
)
// NewCryptoSetupClient creates a new CryptoSetup instance for a client
func NewCryptoSetupClient(
cryptoStream io.ReadWriter,
connID protocol.ConnectionID,
version protocol.VersionNumber,
tlsConf *tls.Config,
params *TransportParameters,
paramsChan chan<- TransportParameters,
handshakeEvent chan<- struct{},
initialVersion protocol.VersionNumber,
negotiatedVersions []protocol.VersionNumber,
logger utils.Logger,
) (CryptoSetup, error) {
nullAEAD, err := crypto.NewNullAEAD(protocol.PerspectiveClient, connID, version)
if err != nil {
return nil, err
}
divNonceChan := make(chan struct{})
cs := &cryptoSetupClient{
cryptoStream: cryptoStream,
hostname: tlsConf.ServerName,
connID: connID,
version: version,
certManager: crypto.NewCertManager(tlsConf),
params: params,
keyDerivation: crypto.DeriveQuicCryptoAESKeys,
nullAEAD: nullAEAD,
paramsChan: paramsChan,
handshakeEvent: handshakeEvent,
initialVersion: initialVersion,
// The server might have sent greased versions in the Version Negotiation packet.
// We need strip those from the list, since they won't be included in the handshake tag.
negotiatedVersions: protocol.StripGreasedVersions(negotiatedVersions),
divNonceChan: divNonceChan,
logger: logger,
}
return cs, nil
}
func (h *cryptoSetupClient) HandleCryptoStream() error {
messageChan := make(chan HandshakeMessage)
errorChan := make(chan error, 1)
go func() {
for {
message, err := ParseHandshakeMessage(h.cryptoStream)
if err != nil {
errorChan <- qerr.Error(qerr.HandshakeFailed, err.Error())
return
}
messageChan <- message
}
}()
for {
if err := h.maybeUpgradeCrypto(); err != nil {
return err
}
h.mutex.RLock()
sendCHLO := h.secureAEAD == nil
h.mutex.RUnlock()
if sendCHLO {
if err := h.sendCHLO(); err != nil {
return err
}
}
var message HandshakeMessage
select {
case <-h.divNonceChan:
// there's no message to process, but we should try upgrading the crypto again
continue
case message = <-messageChan:
case err := <-errorChan:
return err
}
h.logger.Debugf("Got %s", message)
switch message.Tag {
case TagREJ:
if err := h.handleREJMessage(message.Data); err != nil {
return err
}
case TagSHLO:
params, err := h.handleSHLOMessage(message.Data)
if err != nil {
return err
}
// blocks until the session has received the parameters
h.paramsChan <- *params
h.handshakeEvent <- struct{}{}
close(h.handshakeEvent)
default:
return qerr.InvalidCryptoMessageType
}
}
}
func (h *cryptoSetupClient) handleREJMessage(cryptoData map[Tag][]byte) error {
var err error
if stk, ok := cryptoData[TagSTK]; ok {
h.stk = stk
}
if sno, ok := cryptoData[TagSNO]; ok {
h.sno = sno
}
// TODO: what happens if the server sends a different server config in two packets?
if scfg, ok := cryptoData[TagSCFG]; ok {
h.serverConfig, err = parseServerConfig(scfg)
if err != nil {
return err
}
if h.serverConfig.IsExpired() {
return qerr.CryptoServerConfigExpired
}
// now that we have a server config, we can use its OBIT value to generate a client nonce
if len(h.nonc) == 0 {
err = h.generateClientNonce()
if err != nil {
return err
}
}
}
if proof, ok := cryptoData[TagPROF]; ok {
h.proof = proof
h.chloForSignature = h.lastSentCHLO
}
if crt, ok := cryptoData[TagCERT]; ok {
err := h.certManager.SetData(crt)
if err != nil {
return qerr.Error(qerr.InvalidCryptoMessageParameter, "Certificate data invalid")
}
err = h.certManager.Verify(h.hostname)
if err != nil {
h.logger.Infof("Certificate validation failed: %s", err.Error())
return qerr.ProofInvalid
}
}
if h.serverConfig != nil && len(h.proof) != 0 && h.certManager.GetLeafCert() != nil {
validProof := h.certManager.VerifyServerProof(h.proof, h.chloForSignature, h.serverConfig.Get())
if !validProof {
h.logger.Infof("Server proof verification failed")
return qerr.ProofInvalid
}
h.serverVerified = true
}
return nil
}
func (h *cryptoSetupClient) handleSHLOMessage(cryptoData map[Tag][]byte) (*TransportParameters, error) {
h.mutex.Lock()
defer h.mutex.Unlock()
if !h.receivedSecurePacket {
return nil, qerr.Error(qerr.CryptoEncryptionLevelIncorrect, "unencrypted SHLO message")
}
if sno, ok := cryptoData[TagSNO]; ok {
h.sno = sno
}
serverPubs, ok := cryptoData[TagPUBS]
if !ok {
return nil, qerr.Error(qerr.CryptoMessageParameterNotFound, "PUBS")
}
verTag, ok := cryptoData[TagVER]
if !ok {
return nil, qerr.Error(qerr.InvalidCryptoMessageParameter, "server hello missing version list")
}
if !h.validateVersionList(verTag) {
return nil, qerr.Error(qerr.VersionNegotiationMismatch, "Downgrade attack detected")
}
nonce := append(h.nonc, h.sno...)
ephermalSharedSecret, err := h.serverConfig.kex.CalculateSharedKey(serverPubs)
if err != nil {
return nil, err
}
leafCert := h.certManager.GetLeafCert()
h.forwardSecureAEAD, err = h.keyDerivation(
true,
ephermalSharedSecret,
nonce,
h.connID,
h.lastSentCHLO,
h.serverConfig.Get(),
leafCert,
nil,
protocol.PerspectiveClient,
)
if err != nil {
return nil, err
}
h.logger.Debugf("Creating AEAD for forward-secure encryption. Stopping to accept all lower encryption levels.")
params, err := readHelloMap(cryptoData)
if err != nil {
return nil, qerr.InvalidCryptoMessageParameter
}
return params, nil
}
func (h *cryptoSetupClient) validateVersionList(verTags []byte) bool {
numNegotiatedVersions := len(h.negotiatedVersions)
if numNegotiatedVersions == 0 {
return true
}
if len(verTags)%4 != 0 || len(verTags)/4 != numNegotiatedVersions {
return false
}
b := bytes.NewReader(verTags)
for i := 0; i < numNegotiatedVersions; i++ {
v, err := utils.BigEndian.ReadUint32(b)
if err != nil { // should never occur, since the length was already checked
return false
}
if protocol.VersionNumber(v) != h.negotiatedVersions[i] {
return false
}
}
return true
}
func (h *cryptoSetupClient) Open(dst, src []byte, packetNumber protocol.PacketNumber, associatedData []byte) ([]byte, protocol.EncryptionLevel, error) {
h.mutex.RLock()
defer h.mutex.RUnlock()
if h.forwardSecureAEAD != nil {
data, err := h.forwardSecureAEAD.Open(dst, src, packetNumber, associatedData)
if err == nil {
return data, protocol.EncryptionForwardSecure, nil
}
return nil, protocol.EncryptionUnspecified, err
}
if h.secureAEAD != nil {
data, err := h.secureAEAD.Open(dst, src, packetNumber, associatedData)
if err == nil {
h.logger.Debugf("Received first secure packet. Stopping to accept unencrypted packets.")
h.receivedSecurePacket = true
return data, protocol.EncryptionSecure, nil
}
if h.receivedSecurePacket {
return nil, protocol.EncryptionUnspecified, err
}
}
res, err := h.nullAEAD.Open(dst, src, packetNumber, associatedData)
if err != nil {
return nil, protocol.EncryptionUnspecified, err
}
return res, protocol.EncryptionUnencrypted, nil
}
func (h *cryptoSetupClient) GetSealer() (protocol.EncryptionLevel, Sealer) {
h.mutex.RLock()
defer h.mutex.RUnlock()
if h.forwardSecureAEAD != nil {
return protocol.EncryptionForwardSecure, h.forwardSecureAEAD
} else if h.secureAEAD != nil {
return protocol.EncryptionSecure, h.secureAEAD
} else {
return protocol.EncryptionUnencrypted, h.nullAEAD
}
}
func (h *cryptoSetupClient) GetSealerForCryptoStream() (protocol.EncryptionLevel, Sealer) {
return protocol.EncryptionUnencrypted, h.nullAEAD
}
func (h *cryptoSetupClient) GetSealerWithEncryptionLevel(encLevel protocol.EncryptionLevel) (Sealer, error) {
h.mutex.RLock()
defer h.mutex.RUnlock()
switch encLevel {
case protocol.EncryptionUnencrypted:
return h.nullAEAD, nil
case protocol.EncryptionSecure:
if h.secureAEAD == nil {
return nil, errors.New("CryptoSetupClient: no secureAEAD")
}
return h.secureAEAD, nil
case protocol.EncryptionForwardSecure:
if h.forwardSecureAEAD == nil {
return nil, errors.New("CryptoSetupClient: no forwardSecureAEAD")
}
return h.forwardSecureAEAD, nil
}
return nil, errors.New("CryptoSetupClient: no encryption level specified")
}
func (h *cryptoSetupClient) ConnectionState() ConnectionState {
h.mutex.Lock()
defer h.mutex.Unlock()
return ConnectionState{
HandshakeComplete: h.forwardSecureAEAD != nil,
PeerCertificates: h.certManager.GetChain(),
}
}
func (h *cryptoSetupClient) SetDiversificationNonce(divNonce []byte) error {
h.mutex.Lock()
if len(h.diversificationNonce) > 0 {
defer h.mutex.Unlock()
if !bytes.Equal(h.diversificationNonce, divNonce) {
return errConflictingDiversificationNonces
}
return nil
}
h.diversificationNonce = divNonce
h.mutex.Unlock()
h.divNonceChan <- struct{}{}
return nil
}
func (h *cryptoSetupClient) sendCHLO() error {
h.clientHelloCounter++
if h.clientHelloCounter > protocol.MaxClientHellos {
return qerr.Error(qerr.CryptoTooManyRejects, fmt.Sprintf("More than %d rejects", protocol.MaxClientHellos))
}
b := &bytes.Buffer{}
tags, err := h.getTags()
if err != nil {
return err
}
h.addPadding(tags)
message := HandshakeMessage{
Tag: TagCHLO,
Data: tags,
}
h.logger.Debugf("Sending %s", message)
message.Write(b)
_, err = h.cryptoStream.Write(b.Bytes())
if err != nil {
return err
}
h.lastSentCHLO = b.Bytes()
return nil
}
func (h *cryptoSetupClient) getTags() (map[Tag][]byte, error) {
tags := h.params.getHelloMap()
tags[TagSNI] = []byte(h.hostname)
tags[TagPDMD] = []byte("X509")
ccs := h.certManager.GetCommonCertificateHashes()
if len(ccs) > 0 {
tags[TagCCS] = ccs
}
versionTag := make([]byte, 4)
binary.BigEndian.PutUint32(versionTag, uint32(h.initialVersion))
tags[TagVER] = versionTag
if len(h.stk) > 0 {
tags[TagSTK] = h.stk
}
if len(h.sno) > 0 {
tags[TagSNO] = h.sno
}
if h.serverConfig != nil {
tags[TagSCID] = h.serverConfig.ID
leafCert := h.certManager.GetLeafCert()
if leafCert != nil {
certHash, _ := h.certManager.GetLeafCertHash()
xlct := make([]byte, 8)
binary.LittleEndian.PutUint64(xlct, certHash)
tags[TagNONC] = h.nonc
tags[TagXLCT] = xlct
tags[TagKEXS] = []byte("C255")
tags[TagAEAD] = []byte("AESG")
tags[TagPUBS] = h.serverConfig.kex.PublicKey() // TODO: check if 3 bytes need to be prepended
}
}
return tags, nil
}
// add a TagPAD to a tagMap, such that the total size will be bigger than the ClientHelloMinimumSize
func (h *cryptoSetupClient) addPadding(tags map[Tag][]byte) {
var size int
for _, tag := range tags {
size += 8 + len(tag) // 4 bytes for the tag + 4 bytes for the offset + the length of the data
}
paddingSize := protocol.MinClientHelloSize - size
if paddingSize > 0 {
tags[TagPAD] = bytes.Repeat([]byte{0}, paddingSize)
}
}
func (h *cryptoSetupClient) maybeUpgradeCrypto() error {
if !h.serverVerified {
return nil
}
h.mutex.Lock()
defer h.mutex.Unlock()
leafCert := h.certManager.GetLeafCert()
if h.secureAEAD == nil && (h.serverConfig != nil && len(h.serverConfig.sharedSecret) > 0 && len(h.nonc) > 0 && len(leafCert) > 0 && len(h.diversificationNonce) > 0 && len(h.lastSentCHLO) > 0) {
var err error
var nonce []byte
if h.sno == nil {
nonce = h.nonc
} else {
nonce = append(h.nonc, h.sno...)
}
h.secureAEAD, err = h.keyDerivation(
false,
h.serverConfig.sharedSecret,
nonce,
h.connID,
h.lastSentCHLO,
h.serverConfig.Get(),
leafCert,
h.diversificationNonce,
protocol.PerspectiveClient,
)
if err != nil {
return err
}
h.logger.Debugf("Creating AEAD for secure encryption.")
h.handshakeEvent <- struct{}{}
}
return nil
}
func (h *cryptoSetupClient) generateClientNonce() error {
if len(h.nonc) > 0 {
return errClientNonceAlreadyExists
}
nonc := make([]byte, 32)
binary.BigEndian.PutUint32(nonc, uint32(time.Now().Unix()))
if len(h.serverConfig.obit) != 8 {
return errNoObitForClientNonce
}
copy(nonc[4:12], h.serverConfig.obit)
_, err := rand.Read(nonc[12:])
if err != nil {
return err
}
h.nonc = nonc
return nil
}