From 87c935dc1e95b35291d4474d44469ae106edf4e0 Mon Sep 17 00:00:00 2001
From: Zack Scholl <zack.scholl@gmail.com>
Date: Fri, 29 Jun 2018 06:30:02 -0700
Subject: [PATCH] update the curve in client

---
 src/client.go |  2 ++
 src/models.go |  3 ++-
 src/server.go | 17 +----------------
 src/utils.go  | 21 +++++++++++++++++++++
 4 files changed, 26 insertions(+), 17 deletions(-)

diff --git a/src/client.go b/src/client.go
index 3ceada1..02a6e18 100644
--- a/src/client.go
+++ b/src/client.go
@@ -129,6 +129,8 @@ func (c *Croc) processState(cd channelData) (err error) {
 	for key := range cd.State {
 		c.cs.channel.State[key] = cd.State[key]
 	}
+	// update the curve
+	_, c.cs.channel.curve = getCurve(string(c.cs.channel.State["curve"]))
 
 	// TODO:
 	// process the client state
diff --git a/src/models.go b/src/models.go
index 691d543..e10aa5d 100644
--- a/src/models.go
+++ b/src/models.go
@@ -51,6 +51,7 @@ type channelData struct {
 	// Channel is the name of the channel
 	Channel string `json:"channel,omitempty"`
 	// State contains state variables that are public to both parties
+	// contains "curve", "h_k", "hh_k", "x", "y"
 	State map[string][]byte `json:"state"`
 	// TransferReady is set by the relaying when both parties have connected
 	// with their credentials
@@ -61,7 +62,7 @@ type channelData struct {
 	// Error is sent if there is an error
 	Error string `json:"error"`
 
-	// Sent on initialization
+	// Sent on initialization, specific to a single user
 	// UUID is sent out only to one person at a time
 	UUID string `json:"uuid"`
 	// Role is the role the person will play
diff --git a/src/server.go b/src/server.go
index 56853b3..d256815 100644
--- a/src/server.go
+++ b/src/server.go
@@ -1,7 +1,6 @@
 package croc
 
 import (
-	"crypto/elliptic"
 	"net/http"
 	"time"
 
@@ -141,21 +140,7 @@ func (c *Croc) joinChannel(ws *websocket.Conn, p payload) (channel string, err e
 		c.rs.channel[p.Channel].isopen = true
 		c.rs.channel[p.Channel].Ports = c.TcpPorts
 		c.rs.channel[p.Channel].startTime = time.Now()
-		switch curve := p.Curve; curve {
-		case "p224":
-			c.rs.channel[p.Channel].curve = elliptic.P224()
-		case "p256":
-			c.rs.channel[p.Channel].curve = elliptic.P256()
-		case "p384":
-			c.rs.channel[p.Channel].curve = elliptic.P384()
-		case "p521":
-			c.rs.channel[p.Channel].curve = elliptic.P521()
-		default:
-			// TODO:
-			// add SIEC
-			p.Curve = "p256"
-			c.rs.channel[p.Channel].curve = elliptic.P256()
-		}
+		p.Curve, c.rs.channel[p.Channel].curve = getCurve(p.Curve)
 		log.Debugf("(%s) using curve '%s'", p.Channel, p.Curve)
 		c.rs.channel[p.Channel].State["curve"] = []byte(p.Curve)
 	}
diff --git a/src/utils.go b/src/utils.go
index 0554d77..7641b7b 100644
--- a/src/utils.go
+++ b/src/utils.go
@@ -1,6 +1,7 @@
 package croc
 
 import (
+	"crypto/elliptic"
 	"crypto/md5"
 	"fmt"
 	"io"
@@ -69,6 +70,26 @@ func splitFile(fileName string, numPieces int) (err error) {
 	return nil
 }
 
+func getCurve(s string) (curveString string, curve elliptic.Curve) {
+	curveString = s
+	switch s {
+	case "p224":
+		curve = elliptic.P224()
+	case "p256":
+		curve = elliptic.P256()
+	case "p384":
+		curve = elliptic.P384()
+	case "p521":
+		curve = elliptic.P521()
+	default:
+		// TODO:
+		// add SIEC
+		curveString = "p256"
+		curve = elliptic.P256()
+	}
+	return
+}
+
 // copyFile copies a file from src to dst. If src and dst files exist, and are
 // the same, then return success. Otherise, attempt to create a hard link
 // between the two files. If that fail, copy the file contents from src to dst.