-Converted exit status to uint32 (0-255: UNIX exit codes), above for OOB (out-of-band) status

-Failed auth for shell logins now returns extended code CSEBadAuth to client

hkexnet/hkexnet.go

@@ -34,6 +34,16 @@ import (
 	"blitter.com/go/hkexsh/herradurakex"
 )
 
+// const CSExtendedCode - extended (>255 UNIX exit status) codes
+// This indicate channel-related or internal errors
+const (
+	CSEBadAuth     = 1024 // failed login
+	CSETruncCSO           // No CSOExitStatus in payload
+	CSEStillOpen          // Channel closed unexpectedly
+	CSEExecFail           // cmd.Start() (exec) failed
+	CSEPtyExecFail        // pty.Start() (exec w/pty) failed
+)
+
 const (
 	CSONone        = iota // No error, normal packet
 	CSOHmacInvalid        // HMAC mismatch detected on remote end
@@ -77,7 +87,7 @@ type (
 
 		chaff ChaffConfig
 
-		closeStat *uint8        // close status
+		closeStat *uint32       // close status (CSOExitStatus)
 		r         cipher.Stream //read cipherStream
 		rm        hash.Hash
 		w         cipher.Stream //write cipherStream
@@ -86,11 +96,11 @@ type (
 	}
 )
 
-func (hc Conn) GetStatus() uint8 {
+func (hc Conn) GetStatus() uint32 {
 	return *hc.closeStat
 }
 
-func (hc *Conn) SetStatus(stat uint8) {
+func (hc *Conn) SetStatus(stat uint32) {
 	*hc.closeStat = stat
 	//fmt.Println("closeStat:", *hc.closeStat)
 	log.Println("closeStat:", *hc.closeStat)
@@ -177,7 +187,7 @@ 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: hkex.New(0, 0), dBuf: new(bytes.Buffer)}
+	hc = &Conn{m: &sync.Mutex{}, c: c, closeStat: new(uint32), h: hkex.New(0, 0), dBuf: new(bytes.Buffer)}
 	hc.applyConnExtensions(extensions...)
 
 	// Send hkexnet.Conn parameters to remote side
@@ -205,14 +215,16 @@ func Dial(protocol string, ipport string, extensions ...string) (hc *Conn, err e
 
 	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
+	*hc.closeStat = CSEStillOpen // open or prematurely-closed status
 	return
 }
 
 // Close a hkex.Conn
 func (hc *Conn) Close() (err error) {
 	hc.DisableChaff()
-	hc.WritePacket([]byte{byte(*hc.closeStat)}, CSOExitStatus)
+	s := make([]byte, 4)
+	binary.BigEndian.PutUint32(s, *hc.closeStat)
+	hc.WritePacket(s, CSOExitStatus)
 	err = hc.c.Close()
 	log.Println("[Conn Closing]")
 	return
@@ -308,13 +320,13 @@ func (hl *HKExListener) Accept() (hc Conn, err error) {
 	// Open raw Conn c
 	c, err := hl.l.Accept()
 	if err != nil {
-		hc := Conn{m: &sync.Mutex{}, c: nil, h: nil, closeStat: new(uint8), cipheropts: 0, opts: 0,
+		hc := Conn{m: &sync.Mutex{}, c: nil, h: nil, closeStat: new(uint32), cipheropts: 0, opts: 0,
 			r: nil, w: nil}
 		return hc, err
 	}
 	log.Println("[Accepted]")
 
-	hc = Conn{m: &sync.Mutex{}, c: c, h: hkex.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(uint32), WinCh: make(chan WinSize, 1),
 		dBuf: new(bytes.Buffer)}
 
 	// Read in hkexnet.Conn parameters over raw Conn c
@@ -438,7 +450,7 @@ func (hc Conn) Read(b []byte) (n int, err error) {
 				hc.WinCh <- WinSize{hc.Rows, hc.Cols}
 			} else if ctrlStatOp == CSOExitStatus {
 				if len(payloadBytes) > 0 {
-					hc.SetStatus(payloadBytes[0])
+					hc.SetStatus(binary.BigEndian.Uint32(payloadBytes))
 					//!// If remote end is closing with an error, reply we're closing ours
 					//!if hc.GetStatus() != 0 {
 					//!	log.Print("CSOExitStatus:", hc.GetStatus())
@@ -446,7 +458,7 @@ func (hc Conn) Read(b []byte) (n int, err error) {
 					//!}
 				} else {
 					log.Println("[truncated payload, cannot determine CSOExitStatus]")
-					*hc.closeStat = 98
+					*hc.closeStat = CSETruncCSO
 				}
 			} else {
 				hc.dBuf.Write(payloadBytes)
@@ -458,7 +470,7 @@ func (hc Conn) Read(b []byte) (n int, err error) {
 			hTmp := hc.rm.Sum(nil)[0:4]
 			log.Printf("<%04x) HMAC:(i)%s (c)%02x\r\n", decryptN, hex.EncodeToString([]byte(hmacIn[0:])), hTmp)
 
-			if *hc.closeStat > 90 {
+			if *hc.closeStat == CSETruncCSO {
 				log.Println("[cannot verify HMAC]")
 			} else {
 				// Log alert if hmac didn't match, corrupted channel

hkexsh/hkexsh.go

@@ -9,6 +9,7 @@ package main
 
 import (
 	"bytes"
+	"encoding/binary"
 	"flag"
 	"fmt"
 	"io"
@@ -34,7 +35,7 @@ type cmdSpec struct {
 	who        []byte
 	cmd        []byte
 	authCookie []byte
-	status     int // UNIX exit status is uint8, but os.Exit() wants int
+	status     uint32 // exit status (0-255 is std UNIX status)
 }
 
 var (
@@ -98,7 +99,7 @@ func parseNonSwitchArgs(a []string) (user, host, path string, isDest bool, other
 }
 
 // doCopyMode begins a secure hkexsh local<->remote file copy operation.
-func doCopyMode(conn *hkexnet.Conn, remoteDest bool, files string, rec *cmdSpec) (err error, exitStatus int) {
+func doCopyMode(conn *hkexnet.Conn, remoteDest bool, files string, rec *cmdSpec) (err error, exitStatus uint32) {
 	if remoteDest {
 		fmt.Println("local files:", files, "remote filepath:", string(rec.cmd))
 
@@ -161,7 +162,7 @@ func doCopyMode(conn *hkexnet.Conn, remoteDest bool, files string, rec *cmdSpec)
 					// defined for both Unix and Windows and in both cases has
 					// an ExitStatus() method with the same signature.
 					if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
-						exitStatus = status.ExitStatus()
+						exitStatus = uint32(status.ExitStatus())
 						log.Printf("Exit Status: %d", exitStatus)
 						fmt.Print(stdErrBuffer)
 					}
@@ -169,7 +170,9 @@ func doCopyMode(conn *hkexnet.Conn, remoteDest bool, files string, rec *cmdSpec)
 			}
 			//fmt.Println("*** client->server cp finished ***")
 			// Signal other end transfer is complete
-			conn.WritePacket([]byte{byte( /*255*/ rec.status)}, hkexnet.CSOExitStatus)
+			s := make([]byte, 4)
+			binary.BigEndian.PutUint32(s, rec.status)
+			conn.WritePacket(s, hkexnet.CSOExitStatus)
 			_, _ = conn.Read(nil /*ackByte*/)
 		}
 	} else {
@@ -209,7 +212,7 @@ func doCopyMode(conn *hkexnet.Conn, remoteDest bool, files string, rec *cmdSpec)
 					// defined for both Unix and Windows and in both cases has
 					// an ExitStatus() method with the same signature.
 					if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
-						exitStatus = status.ExitStatus()
+						exitStatus = uint32(status.ExitStatus())
 						log.Printf("Exit Status: %d", exitStatus)
 					}
 				}
@@ -217,7 +220,7 @@ func doCopyMode(conn *hkexnet.Conn, remoteDest bool, files string, rec *cmdSpec)
 			// return local status, if nonzero;
 			// otherwise, return remote status if nonzero
 			if exitStatus == 0 {
-				exitStatus = int(conn.GetStatus())
+				exitStatus = uint32(conn.GetStatus())
 			}
 			//fmt.Println("*** server->client cp finished ***")
 		}
@@ -250,7 +253,7 @@ func doShellMode(isInteractive bool, conn *hkexnet.Conn, oldState *hkexsh.State,
 			}
 		}
 
-		rec.status = int(conn.GetStatus())
+		rec.status = uint32(conn.GetStatus())
 		log.Println("rec.status:", rec.status)
 
 		if isInteractive {
@@ -282,7 +285,7 @@ func doShellMode(isInteractive bool, conn *hkexnet.Conn, oldState *hkexsh.State,
 				log.Println(outerr)
 				fmt.Println(outerr)
 				_ = hkexsh.Restore(int(os.Stdin.Fd()), oldState) // Best effort.
-				os.Exit(255)
+				os.Exit(254)
 			}
 			log.Println("[Sent EOF]")
 		}()
@@ -549,7 +552,15 @@ func main() {
 	}
 
 	if rec.status != 0 {
-		fmt.Fprintln(os.Stderr, "Remote end exited with status:", rec.status)
+		fmt.Fprint(os.Stderr, "Remote end ")
+		if rec.status == hkexnet.CSEBadAuth {
+				// shell exit status can't hold CSEBadAuth (uint32)
+				rec.status = 255
+				fmt.Fprintln(os.Stderr, "replied: bad auth")
+		} else {
+			fmt.Fprintln(os.Stderr, "exited with status:", rec.status)
+		}
+
 	}
-	os.Exit(rec.status)
+	os.Exit(int(rec.status))
 }

hkexshd/hkexshd.go

@@ -9,6 +9,7 @@ package main
 
 import (
 	"bytes"
+	"encoding/binary"
 	"flag"
 	"fmt"
 	"io"
@@ -40,7 +41,7 @@ type cmdSpec struct {
 
 /* -------------------------------------------------------------- */
 // Perform a client->server copy
-func runClientToServerCopyAs(who string, conn hkexnet.Conn, fpath string, chaffing bool) (err error, exitStatus int) {
+func runClientToServerCopyAs(who string, conn hkexnet.Conn, fpath string, chaffing bool) (err error, exitStatus uint32) {
 	u, _ := user.Lookup(who)
 	var uid, gid uint32
 	fmt.Sscanf(u.Uid, "%d", &uid)
@@ -99,7 +100,7 @@ func runClientToServerCopyAs(who string, conn hkexnet.Conn, fpath string, chaffi
 	err = c.Start() // returns immediately
 	if err != nil {
 		log.Printf("Command finished with error: %v", err)
-		return err, 253 // !?
+		return err, hkexnet.CSEExecFail // !?
 	} else {
 		if err := c.Wait(); err != nil {
 			//fmt.Println("*** c.Wait() done ***")
@@ -111,7 +112,7 @@ func runClientToServerCopyAs(who string, conn hkexnet.Conn, fpath string, chaffi
 				// defined for both Unix and Windows and in both cases has
 				// an ExitStatus() method with the same signature.
 				if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
-					exitStatus = status.ExitStatus()
+					exitStatus = uint32(status.ExitStatus())
 					log.Printf("Exit Status: %d", exitStatus)
 				}
 			}
@@ -122,7 +123,7 @@ func runClientToServerCopyAs(who string, conn hkexnet.Conn, fpath string, chaffi
 }
 
 // Perform a server->client copy
-func runServerToClientCopyAs(who string, conn hkexnet.Conn, srcPath string, chaffing bool) (err error, exitStatus int) {
+func runServerToClientCopyAs(who string, conn hkexnet.Conn, srcPath string, chaffing bool) (err error, exitStatus uint32) {
 	u, _ := user.Lookup(who)
 	var uid, gid uint32
 	fmt.Sscanf(u.Uid, "%d", &uid)
@@ -179,7 +180,7 @@ func runServerToClientCopyAs(who string, conn hkexnet.Conn, srcPath string, chaf
 	err = c.Start() // returns immediately
 	if err != nil {
 		log.Printf("Command finished with error: %v", err)
-		return err, 253 // !?
+		return err, hkexnet.CSEExecFail // !?
 	} else {
 		if err := c.Wait(); err != nil {
 			//fmt.Println("*** c.Wait() done ***")
@@ -191,7 +192,7 @@ func runServerToClientCopyAs(who string, conn hkexnet.Conn, srcPath string, chaf
 				// defined for both Unix and Windows and in both cases has
 				// an ExitStatus() method with the same signature.
 				if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
-					exitStatus = status.ExitStatus()
+					exitStatus = uint32(status.ExitStatus())
 					log.Printf("Exit Status: %d", exitStatus)
 					// TODO: send stdErrBuffer to client via specific packet
 					// type so it can inform user
@@ -209,7 +210,7 @@ func runServerToClientCopyAs(who string, conn hkexnet.Conn, srcPath string, chaf
 // Run a command (via default shell) as a specific user
 //
 // Uses ptys to support commands which expect a terminal.
-func runShellAs(who string, cmd string, interactive bool, conn hkexnet.Conn, chaffing bool) (err error, exitStatus int) {
+func runShellAs(who string, cmd string, interactive bool, conn hkexnet.Conn, chaffing bool) (err error, exitStatus uint32) {
 	var wg sync.WaitGroup
 	u, _ := user.Lookup(who)
 	var uid, gid uint32
@@ -248,7 +249,7 @@ func runShellAs(who string, cmd string, interactive bool, conn hkexnet.Conn, cha
 	// Start the command with a pty.
 	ptmx, err := pty.Start(c) // returns immediately with ptmx file
 	if err != nil {
-		return err, 0
+		return err, hkexnet.CSEPtyExecFail
 	}
 	// Make sure to close the pty at the end.
 	defer func() { _ = ptmx.Close() }() // Best effort.
@@ -312,11 +313,11 @@ func runShellAs(who string, cmd string, interactive bool, conn hkexnet.Conn, cha
 				// defined for both Unix and Windows and in both cases has
 				// an ExitStatus() method with the same signature.
 				if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
-					exitStatus = status.ExitStatus()
+					exitStatus = uint32(status.ExitStatus())
 					log.Printf("Exit Status: %d", exitStatus)
 				}
 			}
-			conn.SetStatus(uint8(exitStatus))
+			conn.SetStatus(exitStatus)
 		}
 		wg.Wait() // Wait on pty->stdout completion to client
 	}
@@ -446,6 +447,7 @@ func main() {
 					rec.op[0], string(rec.who), string(rec.cmd))
 
 				valid, allowedCmds := hkexsh.AuthUser(string(rec.who), string(rec.authCookie), "/etc/hkexsh.passwd")
+
 				// Security scrub
 				for i := range rec.authCookie {
 					rec.authCookie[i] = 0
@@ -454,6 +456,14 @@ func main() {
 
 				if !valid {
 					log.Println("Invalid user", string(rec.who))
+
+					// Signal other end auth failed
+					rec.status = hkexnet.CSEBadAuth
+					hc.SetStatus(hkexnet.CSEBadAuth)
+					s := make([]byte, 4)
+					binary.BigEndian.PutUint32(s, hkexnet.CSEBadAuth)
+					hc.WritePacket(s, hkexnet.CSOExitStatus)
+
 					hc.Write([]byte(rejectUserMsg()))
 					return
 				}
@@ -474,7 +484,7 @@ func main() {
 						log.Printf("[Error spawning cmd for %s@%s]\n", rec.who, hname)
 					} else {
 						log.Printf("[Command completed for %s@%s, status %d]\n", rec.who, hname, cmdStatus)
-						hc.SetStatus(uint8(cmdStatus))
+						hc.SetStatus(cmdStatus)
 					}
 				} else if rec.op[0] == 's' {
 					// Interactive session
@@ -494,7 +504,7 @@ func main() {
 						log.Printf("[Error spawning shell for %s@%s]\n", rec.who, hname)
 					} else {
 						log.Printf("[Shell completed for %s@%s, status %d]\n", rec.who, hname, cmdStatus)
-						hc.SetStatus(uint8(cmdStatus))
+						hc.SetStatus(cmdStatus)
 					}
 				} else if rec.op[0] == 'D' {
 					// File copy (destination) operation - client copy to server
@@ -511,7 +521,7 @@ func main() {
 					} else {
 						log.Printf("[Command completed for %s@%s, status %d]\n", rec.who, hname, cmdStatus)
 					}
-					hc.SetStatus(uint8(cmdStatus))
+					hc.SetStatus(cmdStatus)
 				} else if rec.op[0] == 'S' {
 					// File copy (src) operation - server copy to client
 					log.Printf("[Server->Client copy]\n")
@@ -528,9 +538,11 @@ func main() {
 					} else {
 						log.Printf("[Command completed for %s@%s, status %d]\n", rec.who, hname, cmdStatus)
 					}
-					hc.SetStatus(uint8(cmdStatus))
+					hc.SetStatus(cmdStatus)
 					// Signal other end transfer is complete
-					hc.WritePacket([]byte{byte( /*255*/ cmdStatus)}, hkexnet.CSOExitStatus)
+					s := make([]byte, 4)
+					binary.BigEndian.PutUint32(s, cmdStatus)
+					hc.WritePacket(s, hkexnet.CSOExitStatus)
 					//fmt.Println("Waiting for EOF from other end.")
 					_, _ = hc.Read(nil /*ackByte*/)
 					//fmt.Println("Got remote end ack.")