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first stab at integrating crypto in our p2p

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- abstract the entire handshake logic in cryptoId.Run() taking session-relevant parameters
- changes in peer to accomodate how the encryption layer would be switched on
- modify arguments of handshake components
- fixed test getting the wrong pubkey but it till crashes on DH in newSession()
This commit is contained in:
zelig 2015-01-19 23:42:13 +00:00 committed by Felix Lange
parent 1803c65e40
commit e252c634cb
3 changed files with 80 additions and 45 deletions
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53
p2p/crypto.go
View File

@ -4,6 +4,7 @@ import (
"crypto/ecdsa" "crypto/ecdsa"
"crypto/rand" "crypto/rand"
"fmt" "fmt"
"io"
"github.com/ethereum/go-ethereum/crypto" "github.com/ethereum/go-ethereum/crypto"
"github.com/obscuren/ecies" "github.com/obscuren/ecies"
@ -53,19 +54,35 @@ func newCryptoId(id ClientIdentity) (self *cryptoId, err error) {
return return
} }
func (self *cryptoId) Run(remotePubKeyDER []byte) (rw *secretRW) { func (self *cryptoId) Run(conn io.ReadWriter, remotePubKeyDER []byte, sessionToken []byte, initiator bool) (token []byte, rw *secretRW, err error) {
if self.initiator { var auth, initNonce, recNonce []byte
auth, initNonce, randomPrvKey, randomPubKey, err := initiator.initAuth(remotePubKeyDER, sessionToken) var randomPrivKey *ecdsa.PrivateKey
var remoteRandomPubKey *ecdsa.PublicKey
respNonce, remoteRandomPubKey, _, _ := initiator.verifyAuthResp(response) if initiator {
if auth, initNonce, randomPrivKey, _, err = self.startHandshake(remotePubKeyDER, sessionToken); err != nil {
return
}
conn.Write(auth)
var response []byte
conn.Read(response)
// write out auth message
// wait for response, then call complete
if recNonce, remoteRandomPubKey, _, err = self.completeHandshake(response); err != nil {
return
}
} else { } else {
// we are listening connection. we are responders in the haandshake. conn.Read(auth)
// we are listening connection. we are responders in the handshake.
// Extract info from the authentication. The initiator starts by sending us a handshake that we need to respond to. // Extract info from the authentication. The initiator starts by sending us a handshake that we need to respond to.
response, remoteRespNonce, remoteInitNonce, remoteRandomPrivKey, _ := responder.verifyAuth(auth, sessionToken, pubInit) // so we read auth message first, then respond
var response []byte
if response, recNonce, initNonce, randomPrivKey, err = self.respondToHandshake(auth, remotePubKeyDER, sessionToken); err != nil {
return
}
remoteRandomPubKey = &randomPrivKey.PublicKey
conn.Write(response)
} }
initSessionToken, initSecretRW, _ := initiator.newSession(initNonce, respNonce, auth, randomPrvKey, remoteRandomPubKey) return self.newSession(initNonce, recNonce, auth, randomPrivKey, remoteRandomPubKey)
respSessionToken, respSecretRW, _ := responder.newSession(remoteInitNonce, remoteRespNonce, auth, remoteRandomPrivKey, randomPubKey)
} }
/* startHandshake is called by peer if it initiated the connection. /* startHandshake is called by peer if it initiated the connection.
@ -83,9 +100,9 @@ The handshake is the process by which the peers establish their connection for a
*/ */
func (self *cryptoId) startHandshake(remotePubKeyDER, sessionToken []byte) (auth []byte, initNonce []byte, randomPrvKey *ecdsa.PrivateKey, randomPubKey *ecdsa.PublicKey, err error) { func (self *cryptoId) startHandshake(remotePubKeyDER, sessionToken []byte) (auth []byte, initNonce []byte, randomPrvKey *ecdsa.PrivateKey, remotePubKey *ecdsa.PublicKey, err error) {
// session init, common to both parties // session init, common to both parties
remotePubKey := crypto.ToECDSAPub(remotePubKeyDER) remotePubKey = crypto.ToECDSAPub(remotePubKeyDER)
if remotePubKey == nil { if remotePubKey == nil {
err = fmt.Errorf("invalid remote public key") err = fmt.Errorf("invalid remote public key")
return return
@ -160,8 +177,14 @@ func (self *cryptoId) startHandshake(remotePubKeyDER, sessionToken []byte) (auth
} }
// verifyAuth is called by peer if it accepted (but not initiated) the connection // verifyAuth is called by peer if it accepted (but not initiated) the connection
func (self *cryptoId) respondToHandshake(auth, sessionToken []byte, remotePubKey *ecdsa.PublicKey) (authResp []byte, respNonce []byte, initNonce []byte, randomPrvKey *ecdsa.PrivateKey, err error) { func (self *cryptoId) respondToHandshake(auth, remotePubKeyDER, sessionToken []byte) (authResp []byte, respNonce []byte, initNonce []byte, randomPrivKey *ecdsa.PrivateKey, err error) {
var msg []byte var msg []byte
remotePubKey := crypto.ToECDSAPub(remotePubKeyDER)
if remotePubKey == nil {
err = fmt.Errorf("invalid public key")
return
}
fmt.Printf("encrypted message received: %v %x\n used pubkey: %x\n", len(auth), auth, crypto.FromECDSAPub(self.pubKey)) fmt.Printf("encrypted message received: %v %x\n used pubkey: %x\n", len(auth), auth, crypto.FromECDSAPub(self.pubKey))
// they prove that msg is meant for me, // they prove that msg is meant for me,
// I prove I possess private key if i can read it // I prove I possess private key if i can read it
@ -210,12 +233,12 @@ func (self *cryptoId) respondToHandshake(auth, sessionToken []byte, remotePubKey
return return
} }
// generate random keypair for session // generate random keypair for session
if randomPrvKey, err = crypto.GenerateKey(); err != nil { if randomPrivKey, err = crypto.GenerateKey(); err != nil {
return return
} }
// responder auth message // responder auth message
// E(remote-pubk, ecdhe-random-pubk || nonce || 0x0) // E(remote-pubk, ecdhe-random-pubk || nonce || 0x0)
copy(resp[:keyLen], crypto.FromECDSAPub(&randomPrvKey.PublicKey)) copy(resp[:keyLen], crypto.FromECDSAPub(&randomPrivKey.PublicKey))
// nonce is already in the slice // nonce is already in the slice
resp[resLen-1] = tokenFlag resp[resLen-1] = tokenFlag

39
p2p/crypto_test.go
View File

@ -11,44 +11,43 @@ import (
func TestCryptoHandshake(t *testing.T) { func TestCryptoHandshake(t *testing.T) {
var err error var err error
var sessionToken []byte var sessionToken []byte
prvInit, _ := crypto.GenerateKey() prv0, _ := crypto.GenerateKey()
pubInit := &prvInit.PublicKey pub0 := &prv0.PublicKey
prvResp, _ := crypto.GenerateKey() prv1, _ := crypto.GenerateKey()
pubResp := &prvResp.PublicKey pub1 := &prv1.PublicKey
var initiator, responder *cryptoId var initiator, receiver *cryptoId
if initiator, err = newCryptoId(&peerId{crypto.FromECDSA(prvInit), crypto.FromECDSAPub(pubInit)}); err != nil { if initiator, err = newCryptoId(&peerId{crypto.FromECDSA(prv0), crypto.FromECDSAPub(pub0)}); err != nil {
return return
} }
if responder, err = newCryptoId(&peerId{crypto.FromECDSA(prvResp), crypto.FromECDSAPub(pubResp)}); err != nil { if receiver, err = newCryptoId(&peerId{crypto.FromECDSA(prv1), crypto.FromECDSAPub(pub1)}); err != nil {
return return
} }
auth, initNonce, randomPrvKey, randomPubKey, _ := initiator.initAuth(responder.pubKeyDER, sessionToken) // simulate handshake by feeding output to input
auth, initNonce, randomPrivKey, _, _ := initiator.startHandshake(receiver.pubKeyDER, sessionToken)
response, remoteRecNonce, remoteInitNonce, remoteRandomPrivKey, _ := receiver.respondToHandshake(auth, crypto.FromECDSAPub(pub0), sessionToken)
recNonce, remoteRandomPubKey, _, _ := initiator.completeHandshake(response)
response, remoteRespNonce, remoteInitNonce, remoteRandomPrivKey, _ := responder.verifyAuth(auth, sessionToken, pubInit) initSessionToken, initSecretRW, _ := initiator.newSession(initNonce, recNonce, auth, randomPrivKey, remoteRandomPubKey)
recSessionToken, recSecretRW, _ := receiver.newSession(remoteInitNonce, remoteRecNonce, auth, remoteRandomPrivKey, &randomPrivKey.PublicKey)
respNonce, remoteRandomPubKey, _, _ := initiator.verifyAuthResp(response) fmt.Printf("%x\n%x\n%x\n%x\n%x\n%x\n%x\n%x\n%x\n%x\n", auth, initNonce, response, remoteRecNonce, remoteInitNonce, remoteRandomPubKey, recNonce, &randomPrivKey.PublicKey, initSessionToken, initSecretRW)
initSessionToken, initSecretRW, _ := initiator.newSession(initNonce, respNonce, auth, randomPrvKey, remoteRandomPubKey) if !bytes.Equal(initSessionToken, recSessionToken) {
respSessionToken, respSecretRW, _ := responder.newSession(remoteInitNonce, remoteRespNonce, auth, remoteRandomPrivKey, randomPubKey)
fmt.Printf("%x\n%x\n%x\n%x\n%x\n%x\n%x\n%x\n%x\n%x\n", auth, initNonce, response, remoteRespNonce, remoteInitNonce, remoteRandomPubKey, respNonce, randomPubKey, initSessionToken, initSecretRW)
if !bytes.Equal(initSessionToken, respSessionToken) {
t.Errorf("session tokens do not match") t.Errorf("session tokens do not match")
} }
// aesSecret, macSecret, egressMac, ingressMac // aesSecret, macSecret, egressMac, ingressMac
if !bytes.Equal(initSecretRW.aesSecret, respSecretRW.aesSecret) { if !bytes.Equal(initSecretRW.aesSecret, recSecretRW.aesSecret) {
t.Errorf("AES secrets do not match") t.Errorf("AES secrets do not match")
} }
if !bytes.Equal(initSecretRW.macSecret, respSecretRW.macSecret) { if !bytes.Equal(initSecretRW.macSecret, recSecretRW.macSecret) {
t.Errorf("macSecrets do not match") t.Errorf("macSecrets do not match")
} }
if !bytes.Equal(initSecretRW.egressMac, respSecretRW.egressMac) { if !bytes.Equal(initSecretRW.egressMac, recSecretRW.egressMac) {
t.Errorf("egressMacs do not match") t.Errorf("egressMacs do not match")
} }
if !bytes.Equal(initSecretRW.ingressMac, respSecretRW.ingressMac) { if !bytes.Equal(initSecretRW.ingressMac, recSecretRW.ingressMac) {
t.Errorf("ingressMacs do not match") t.Errorf("ingressMacs do not match")
} }

33
p2p/peer.go
View File

@ -222,9 +222,9 @@ func (p *Peer) loop() (reason DiscReason, err error) {
defer close(p.closed) defer close(p.closed)
defer p.conn.Close() defer p.conn.Close()
var readLoop func(chan Msg, chan error, chan bool) var readLoop func(chan<- Msg, chan<- error, <-chan bool)
if p.cryptoHandshake { if p.cryptoHandshake {
if readLoop, err := p.handleCryptoHandshake(); err != nil { if readLoop, err = p.handleCryptoHandshake(); err != nil {
// from here on everything can be encrypted, authenticated // from here on everything can be encrypted, authenticated
return DiscProtocolError, err // no graceful disconnect return DiscProtocolError, err // no graceful disconnect
} }
@ -332,20 +332,33 @@ func (p *Peer) dispatch(msg Msg, protoDone chan struct{}) (wait bool, err error)
return wait, nil return wait, nil
} }
func (p *Peer) handleCryptoHandshake() (err error) { type readLoop func(chan<- Msg, chan<- error, <-chan bool)
func (p *Peer) handleCryptoHandshake() (loop readLoop, err error) {
// cryptoId is just created for the lifecycle of the handshake // cryptoId is just created for the lifecycle of the handshake
// it is survived by an encrypted readwriter // it is survived by an encrypted readwriter
if p.dialAddr != 0 { // this should have its own method Outgoing() bool var initiator bool
var sessionToken []byte
if p.dialAddr != nil { // this should have its own method Outgoing() bool
initiator = true initiator = true
} }
// create crypto layer // create crypto layer
cryptoId := newCryptoId(p.identity, initiator, sessionToken) // this could in principle run only once but maybe we want to allow
// run on peer // identity switching
if rw, err := cryptoId.Run(p.Pubkey()); err != nil { var crypto *cryptoId
return err if crypto, err = newCryptoId(p.ourID); err != nil {
return
} }
p.conn = rw.Run(p.conn) // run on peer
// this bit handles the handshake and creates a secure communications channel with
// var rw *secretRW
if sessionToken, _, err = crypto.Run(p.conn, p.Pubkey(), sessionToken, initiator); err != nil {
return
}
loop = func(msg chan<- Msg, err chan<- error, next <-chan bool) {
// this is the readloop :)
}
return
} }
func (p *Peer) startBaseProtocol() { func (p *Peer) startBaseProtocol() {