From 6788fd1adf0d8a227ee9a48536c4c277e71b6eee Mon Sep 17 00:00:00 2001
From: Russ Magee <rmagee@gmail.com>
Date: Tue, 2 Oct 2018 11:03:10 -0700
Subject: [PATCH] Made padding size random (max/2, max]; use of improved goutmp
 host lookup

---
 hkexnet/hkexnet.go |  5 +++--
 hkexshd/hkexshd.go | 16 ++++++----------
 2 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/hkexnet/hkexnet.go b/hkexnet/hkexnet.go
index 890502b..d72c0fc 100644
--- a/hkexnet/hkexnet.go
+++ b/hkexnet/hkexnet.go
@@ -590,8 +590,9 @@ func (hc *Conn) WritePacket(b []byte, op byte) (n int, err error) {
 	}
 
 	//Padding
-	padLen := PAD_SZ - ((uint32(len(b)) + PAD_SZ) % PAD_SZ)
-	if padLen == PAD_SZ {
+	padSz := (rand.Intn(PAD_SZ) / 2) + (PAD_SZ / 2)
+	padLen := padSz - ((len(b) + padSz) % padSz)
+	if padLen == padSz {
 		// No padding required
 		padLen = 0
 	}
diff --git a/hkexshd/hkexshd.go b/hkexshd/hkexshd.go
index b834b42..a36ac89 100755
--- a/hkexshd/hkexshd.go
+++ b/hkexshd/hkexshd.go
@@ -22,7 +22,6 @@ import (
 	"os/exec"
 	"os/user"
 	"path"
-	"strings"
 	"sync"
 	"syscall"
 
@@ -353,7 +352,7 @@ func GenAuthToken(who string, connhost string) string {
 // Compare to 'serverp.go' in this directory to see the equivalence.
 func main() {
 	version := hkexsh.Version
-	
+
 	var vopt bool
 	var chaffEnabled bool
 	var chaffFreqMin uint
@@ -510,7 +509,7 @@ func main() {
 				if rec.Op()[0] == 'A' {
 					// Generate automated login token
 					addr := hc.RemoteAddr()
-					hname := strings.Split(addr.String(), ":")[0]
+					hname := goutmp.GetHost(addr.String())
 					log.Printf("[Generating autologin token for [%s@%s]]\n", rec.Who(), hname)
 					token := GenAuthToken(string(rec.Who()), string(rec.ConnHost()))
 					tokenCmd := fmt.Sprintf("echo \"%s\" | tee -a ~/.hkexsh_id", token)
@@ -527,9 +526,7 @@ func main() {
 				} else if rec.Op()[0] == 'c' {
 					// Non-interactive command
 					addr := hc.RemoteAddr()
-					//hname := goutmp.GetHost(addr.String())
-					hname := strings.Split(addr.String(), ":")[0]
-
+					hname := goutmp.GetHost(addr.String())
 					log.Printf("[Running command for [%s@%s]]\n", rec.Who(), hname)
 					runErr, cmdStatus := runShellAs(string(rec.Who()), string(rec.TermType()), string(rec.Cmd()), false, hc, chaffEnabled)
 					// Returned hopefully via an EOF or exit/logout;
@@ -544,8 +541,7 @@ func main() {
 				} else if rec.Op()[0] == 's' {
 					// Interactive session
 					addr := hc.RemoteAddr()
-					//hname := goutmp.GetHost(addr.String())
-					hname := strings.Split(addr.String(), ":")[0]
+					hname := goutmp.GetHost(addr.String())
 					log.Printf("[Running shell for [%s@%s]]\n", rec.Who(), hname)
 
 					utmpx := goutmp.Put_utmp(string(rec.Who()), hname)
@@ -565,7 +561,7 @@ func main() {
 					// File copy (destination) operation - client copy to server
 					log.Printf("[Client->Server copy]\n")
 					addr := hc.RemoteAddr()
-					hname := strings.Split(addr.String(), ":")[0]
+					hname := goutmp.GetHost(addr.String())
 					log.Printf("[Running copy for [%s@%s]]\n", rec.Who(), hname)
 					runErr, cmdStatus := runClientToServerCopyAs(string(rec.Who()), string(rec.TermType()), hc, string(rec.Cmd()), chaffEnabled)
 					// Returned hopefully via an EOF or exit/logout;
@@ -587,7 +583,7 @@ func main() {
 					// File copy (src) operation - server copy to client
 					log.Printf("[Server->Client copy]\n")
 					addr := hc.RemoteAddr()
-					hname := strings.Split(addr.String(), ":")[0]
+					hname := goutmp.GetHost(addr.String())
 					log.Printf("[Running copy for [%s@%s]]\n", rec.Who(), hname)
 					runErr, cmdStatus := runServerToClientCopyAs(string(rec.Who()), string(rec.TermType()), hc, string(rec.Cmd()), chaffEnabled)
 					// Returned hopefully via an EOF or exit/logout;