reorg to separate core KEx and net layer from app

Makefile

@@ -1,6 +1,7 @@
-.PHONY: clean lib client server passwd
+.PHONY: info clean lib client server passwd
 
-SUBDIRS = hkexpasswd hkexsh hkexshd
+SUBDIRS = hkexnet herradurakex hkexpasswd hkexsh hkexshd
+LIBS = hkexnet herradurakex
 
 all: lib client server passwd
 

herradurakex/Makefile

@@ -0,0 +1,17 @@
+.PHONY: info clean all lib
+
+all: lib
+
+clean:
+	go clean .
+
+lib: info
+	go install .
+
+ifneq ($(MSYSTEM),)
+info:
+	@echo "building for Windows (MSYS)"
+else
+info:
+	@echo "building for Linux"
+endif

herradurakex/herradurakex.go

@@ -15,7 +15,7 @@
 // distribution)
 //
 // golang implementation by Russ Magee (rmagee_at_gmail.com)
-package hkexsh
+package hkex
 
 /*  Herradura - a Key exchange scheme in the style of Diffie-Hellman Key Exchange.
     Copyright (C) 2017 Omar Alejandro Herrera Reyna
@@ -52,7 +52,7 @@ type HerraduraKEx struct {
 	randctx      *rand.Rand
 	a            *big.Int
 	b            *big.Int
-	d, PeerD     *big.Int
+	d, peerD     *big.Int
 	fa           *big.Int
 }
 
@@ -148,22 +148,37 @@ func (h *HerraduraKEx) fscxRevolve(x, y *big.Int, passes int) (result *big.Int)
 
 // D returns the D (FSCX Revolved) value, input to generate FA
 // (the value for peer KEx)
-func (h *HerraduraKEx) D() *big.Int {
+func (h HerraduraKEx) D() *big.Int {
 	return h.d
 }
 
-// FA returns the FA value, which must be sent to peer for KEx.
-func (h *HerraduraKEx) FA() {
-	h.fa = h.fscxRevolve(h.PeerD, h.b, h.intSz-h.pubSz)
+// PeerD returns the peer D value
+func (h HerraduraKEx) PeerD() *big.Int {
+	return h.peerD
+}
+
+// SetPeerD stores the received peer's D value (contents, not ptr)
+func (h *HerraduraKEx) SetPeerD(pd *big.Int) {
+	*h.peerD = *pd
+}
+
+// ComputeFA computes the FA value, which must be sent to peer for KEx.
+func (h *HerraduraKEx) ComputeFA() {
+	h.fa = h.fscxRevolve(h.peerD, h.b, h.intSz-h.pubSz)
 	h.fa.Xor(h.fa, h.a)
 }
 
+// FA returns the computed FA value
+func (h HerraduraKEx) FA() *big.Int {
+	return h.fa
+}
+
 // Output HerraduraKEx type value as a string. Implements Stringer interface.
 func (h *HerraduraKEx) String() string {
-	return fmt.Sprintf("s:%d p:%d\na:%s\nb:%s\nd:->%s\n<-PeerD:%s\nfa:%s",
+	return fmt.Sprintf("s:%d p:%d\na:%s\nb:%s\nd:->%s\n<-peerD:%s\nfa:%s",
 		h.intSz, h.pubSz,
 		h.a.Text(16), h.b.Text(16),
 		h.d.Text(16),
-		h.PeerD.Text(16),
+		h.peerD.Text(16),
 		h.fa.Text(16))
 }

hkexnet/Makefile

@@ -0,0 +1,17 @@
+.PHONY: info clean lib
+
+all: lib
+
+clean:
+	go clean .
+
+lib: info
+	go install .
+
+ifneq ($(MSYSTEM),)
+info:
+	@echo "Building for Windows (MSYS)"
+else
+info:
+	@echo "Building for Linux"
+endif

hkexnet/hkexchan.go

@@ -1,4 +1,4 @@
-package hkexsh
+package hkexnet
 
 // Copyright (c) 2017-2018 Russell Magee
 // Licensed under the terms of the MIT license (see LICENSE.mit in this

hkexnet/hkexnet.go

@@ -7,7 +7,7 @@
 //
 // golang implementation by Russ Magee (rmagee_at_gmail.com)
 
-package hkexsh
+package hkexnet
 
 // Implementation of HKEx-wrapped versions of the golang standard
 // net package interfaces, allowing clients and servers to simply replace
@@ -30,6 +30,8 @@ import (
 	"strings"
 	"sync"
 	"time"
+
+	"blitter.com/go/hkexsh/herradurakex"
 )
 
 const (
@@ -59,7 +61,7 @@ type ChaffConfig struct {
 type Conn struct {
 	m          *sync.Mutex
 	c          net.Conn // which also implements io.Reader, io.Writer, ...
-	h          *HerraduraKEx
+	h          *hkex.HerraduraKEx
 	cipheropts uint32 // post-KEx cipher/hmac options
 	opts       uint32 // post-KEx protocol options (caller-defined)
 	WinCh      chan WinSize
@@ -166,12 +168,12 @@ func Dial(protocol string, ipport string, extensions ...string) (hc *Conn, err e
 		return nil, err
 	}
 	// Init hkexnet.Conn hc over net.Conn c
-	hc = &Conn{m: &sync.Mutex{}, c: c, closeStat: new(uint8), h: New(0, 0), dBuf: new(bytes.Buffer)}
+	hc = &Conn{m: &sync.Mutex{}, c: c, closeStat: new(uint8), h: hkex.New(0, 0), dBuf: new(bytes.Buffer)}
 	hc.applyConnExtensions(extensions...)
 
 	// Send hkexnet.Conn parameters to remote side
 	// d is value for Herradura key exchange
-	fmt.Fprintf(c, "0x%s\n%08x:%08x\n", hc.h.d.Text(16),
+	fmt.Fprintf(c, "0x%s\n%08x:%08x\n", hc.h.D().Text(16),
 		hc.cipheropts, hc.opts)
 
 	d := big.NewInt(0)
@@ -179,20 +181,21 @@ func Dial(protocol string, ipport string, extensions ...string) (hc *Conn, err e
 	if err != nil {
 		return nil, err
 	}
+	// Read peer D over net.Conn (c)
 	_, err = fmt.Fscanf(c, "%08x:%08x\n",
 		&hc.cipheropts, &hc.opts)
 	if err != nil {
 		return nil, err
 	}
 
-	hc.h.PeerD = d
-	log.Printf("** D:%s\n", hc.h.d.Text(16))
-	log.Printf("**(c)** peerD:%s\n", hc.h.PeerD.Text(16))
-	hc.h.FA()
-	log.Printf("**(c)** FA:%s\n", hc.h.fa)
+	hc.h.SetPeerD(d)
+	log.Printf("** local D:%s\n", hc.h.D().Text(16))
+	log.Printf("**(c)** peer D:%s\n", hc.h.PeerD().Text(16))
+	hc.h.ComputeFA()
+	log.Printf("**(c)** FA:%s\n", hc.h.FA())
 
-	hc.r, hc.rm, err = hc.getStream(hc.h.fa)
-	hc.w, hc.wm, err = hc.getStream(hc.h.fa)
+	hc.r, hc.rm, err = hc.getStream(hc.h.FA())
+	hc.w, hc.wm, err = hc.getStream(hc.h.FA())
 
 	*hc.closeStat = 99 // open or prematurely-closed status
 	return
@@ -304,7 +307,7 @@ func (hl HKExListener) Accept() (hc Conn, err error) {
 	}
 	log.Println("[Accepted]")
 
-	hc = Conn{m: &sync.Mutex{}, c: c, h: New(0, 0), closeStat: new(uint8), WinCh: make(chan WinSize, 1),
+	hc = Conn{m: &sync.Mutex{}, c: c, h: hkex.New(0, 0), closeStat: new(uint8), WinCh: make(chan WinSize, 1),
 		dBuf: new(bytes.Buffer)}
 
 	// Read in hkexnet.Conn parameters over raw Conn c
@@ -321,17 +324,18 @@ func (hl HKExListener) Accept() (hc Conn, err error) {
 	if err != nil {
 		return hc, err
 	}
-	hc.h.PeerD = d
-	log.Printf("** D:%s\n", hc.h.d.Text(16))
-	log.Printf("**(s)** peerD:%s\n", hc.h.PeerD.Text(16))
+	hc.h.SetPeerD(d)
+	log.Printf("** D:%s\n", hc.h.D().Text(16))
+	log.Printf("**(s)** peerD:%s\n", hc.h.PeerD().Text(16))
 	hc.h.FA()
-	log.Printf("**(s)** FA:%s\n", hc.h.fa)
-
-	fmt.Fprintf(c, "0x%s\n%08x:%08x\n", hc.h.d.Text(16),
+	log.Printf("**(s)** FA:%s\n", hc.h.FA())
+	
+	// Send D and cipheropts/conn_opts to peer
+	fmt.Fprintf(c, "0x%s\n%08x:%08x\n", hc.h.D().Text(16),
 		hc.cipheropts, hc.opts)
 
-	hc.r, hc.rm, err = hc.getStream(hc.h.fa)
-	hc.w, hc.wm, err = hc.getStream(hc.h.fa)
+	hc.r, hc.rm, err = hc.getStream(hc.h.FA())
+	hc.w, hc.wm, err = hc.getStream(hc.h.FA())
 	return
 }