Additional buffer bounds checks

[govpn.git] / src / govpn / handshake.go

diff --git a/src/govpn/handshake.go b/src/govpn/handshake.go
index 0aa65bd624e4e9366db2275b3acff5d6fc04ad1d..24a0f1f5a7dbb44ef486c3f5d1b5151418615f83 100644 (file)
--- a/src/govpn/handshake.go
+++ b/src/govpn/handshake.go
@@ -191,7 +191,7 @@ func HandshakeStart(addr string, conn io.Writer, conf *PeerConf) *Handshake {
 // authenticated Peer is ready, then return nil.
 func (h *Handshake) Server(data []byte) *Peer {
        // R + ENC(H(DSAPub), R, El(CDHPub)) + IDtag
-       if h.rNonce == nil {
+       if h.rNonce == nil && len(data) >= 48 {
                // Generate DH keypair
                var dhPubRepr *[32]byte
                h.dhPriv, dhPubRepr = dhKeypairGen()
@@ -237,7 +237,7 @@ func (h *Handshake) Server(data []byte) *Peer {
                h.LastPing = time.Now()
        } else
        // ENC(K, R+1, RS + RC + SC + Sign(DSAPriv, K)) + IDtag
-       if h.rClient == nil {
+       if h.rClient == nil && len(data) >= 120 {
                // Decrypted Rs compare rServer
                dec := make([]byte, RSize+RSize+SSize+ed25519.SignatureSize)
                salsa20.XORKeyStream(
@@ -290,7 +290,7 @@ func (h *Handshake) Server(data []byte) *Peer {
 // authenticated Peer is ready, then return nil.
 func (h *Handshake) Client(data []byte) *Peer {
        // ENC(H(DSAPub), R+1, El(SDHPub)) + ENC(K, R, RS + SS) + IDtag
-       if h.rServer == nil && h.key == nil {
+       if h.rServer == nil && h.key == nil && len(data) >= 80 {
                // Decrypt remote public key and compute shared key
                sDHRepr := new([32]byte)
                salsa20.XORKeyStream(sDHRepr[:], data[:32], h.rNonceNext(1), h.dsaPubH)
@@ -334,7 +334,7 @@ func (h *Handshake) Client(data []byte) *Peer {
                h.LastPing = time.Now()
        } else
        // ENC(K, R+2, RC) + IDtag
-       if h.key != nil {
+       if h.key != nil && len(data) >= 16 {
                // Decrypt rClient
                dec := make([]byte, RSize)
                salsa20.XORKeyStream(dec, data[:RSize], h.rNonceNext(2), h.key)