add banner opt back (#106)

* add banner opt back

* happy lint

cmd/sshpiperd/daemon.go

@@ -56,6 +56,23 @@ func newDaemon(ctx *cli.Context) (*daemon, error) {
 		return nil, fmt.Errorf("failed to listen for connection: %v", err)
 	}
 
+	bannertext := ctx.String("banner-text")
+	bannerfile := ctx.String("banner-file")
+
+	if bannertext != "" || bannerfile != "" {
+		config.BannerCallback = func(_ ssh.ConnMetadata, _ ssh.ChallengeContext) string {
+			if bannerfile != "" {
+				text, err := os.ReadFile(bannerfile)
+				if err != nil {
+					log.Warnf("cannot read banner file %v: %v", bannerfile, err)
+				} else {
+					return string(text)
+				}
+			}
+			return bannertext
+		}
+	}
+
 	return &daemon{
 		config:         config,
 		lis:            lis,

cmd/sshpiperd/main.go

@@ -115,6 +115,18 @@ func main() {
 				Usage:   "create typescript format screen recording and save into the directory see https://linux.die.net/man/1/script",
 				EnvVars: []string{"SSHPIPERD_TYPESCRIPT_LOG_DIR"},
 			},
+			&cli.StringFlag{
+				Name:    "banner-text",
+				Value:   "",
+				Usage:   "display a banner before authentication, would be ignored if banner file was set",
+				EnvVars: []string{"SSHPIPERD_BANNERTEXT"},
+			},
+			&cli.StringFlag{
+				Name:    "banner-file",
+				Value:   "",
+				Usage:   "display a banner from file before authentication",
+				EnvVars: []string{"SSHPIPERD_BANNERFILE"},
+			},
 		},
 		Action: func(ctx *cli.Context) error {
 			level, err := log.ParseLevel(ctx.String("log-level"))

e2e/banner_test.go

@@ -0,0 +1,118 @@
+package e2e_test
+
+import (
+	"os"
+	"testing"
+
+	"github.com/google/uuid"
+)
+
+func TestBanner(t *testing.T) {
+
+	t.Run("args", func(t *testing.T) {
+		piperaddr, piperport := nextAvailablePiperAddress()
+		randtext := uuid.New().String()
+
+		piper, _, _, err := runCmd("/sshpiperd/sshpiperd",
+			"--banner-text",
+			randtext,
+			"-p",
+			piperport,
+			"/sshpiperd/plugins/fixed",
+			"--target",
+			"host-password:2222",
+		)
+
+		if err != nil {
+			t.Errorf("failed to run sshpiperd: %v", err)
+		}
+
+		defer killCmd(piper)
+
+		waitForEndpointReady(piperaddr)
+
+		c, _, stdout, err := runCmd(
+			"ssh",
+			"-v",
+			"-o",
+			"StrictHostKeyChecking=no",
+			"-o",
+			"UserKnownHostsFile=/dev/null",
+			"-p",
+			piperport,
+			"-l",
+			"user",
+			"127.0.0.1",
+		)
+
+		if err != nil {
+			t.Errorf("failed to ssh to piper, %v", err)
+		}
+
+		defer killCmd(c)
+
+		waitForStdoutContains(stdout, randtext, func(_ string) {
+		})
+	})
+
+	t.Run("file", func(t *testing.T) {
+
+		piperaddr, piperport := nextAvailablePiperAddress()
+		randtext := uuid.New().String()
+
+		bannerfile, err := os.CreateTemp("", "banner")
+		if err != nil {
+			t.Errorf("failed to create temp file: %v", err)
+		}
+		defer os.Remove(bannerfile.Name())
+
+		if _, err := bannerfile.WriteString(randtext); err != nil {
+			t.Errorf("failed to write to temp file: %v", err)
+		}
+
+		if err := bannerfile.Close(); err != nil {
+			t.Errorf("failed to close temp file: %v", err)
+		}
+
+		piper, _, _, err := runCmd("/sshpiperd/sshpiperd",
+			"--banner-file",
+			bannerfile.Name(),
+			"-p",
+			piperport,
+			"/sshpiperd/plugins/fixed",
+			"--target",
+			"host-password:2222",
+		)
+
+		if err != nil {
+			t.Errorf("failed to run sshpiperd: %v", err)
+		}
+
+		defer killCmd(piper)
+
+		waitForEndpointReady(piperaddr)
+
+		c, _, stdout, err := runCmd(
+			"ssh",
+			"-v",
+			"-o",
+			"StrictHostKeyChecking=no",
+			"-o",
+			"UserKnownHostsFile=/dev/null",
+			"-p",
+			piperport,
+			"-l",
+			"user",
+			"127.0.0.1",
+		)
+
+		if err != nil {
+			t.Errorf("failed to ssh to piper, %v", err)
+		}
+
+		defer killCmd(c)
+
+		waitForStdoutContains(stdout, randtext, func(_ string) {
+		})
+	})
+}

e2e/main_test.go

@@ -113,21 +113,20 @@ func runCmdAndWait(cmd string, args ...string) error {
 	return c.Wait()
 }
 
-func enterPassword(stdin io.Writer, stdout io.Reader, password string) {
+func waitForStdoutContains(stdout io.Reader, text string, cb func(string)) {
 	st := time.Now()
 	for {
 		scanner := bufio.NewScanner(stdout)
 		for scanner.Scan() {
 			line := scanner.Text()
-			if strings.Contains(line, "'s password") {
-				_, _ = stdin.Write([]byte(fmt.Sprintf("%v\n", password)))
-				log.Printf("got password prompt, sending password")
+			if strings.Contains(line, text) {
+				cb(line)
 				return
 			}
 		}
 
 		if time.Since(st) > waitTimeout {
-			log.Panic("timeout waiting for password prompt")
+			log.Panicf("timeout waiting for [%s] from prompt", text)
 			return
 		}
 
@@ -135,6 +134,13 @@ func enterPassword(stdin io.Writer, stdout io.Reader, password string) {
 	}
 }
 
+func enterPassword(stdin io.Writer, stdout io.Reader, password string) {
+	waitForStdoutContains(stdout, "'s password", func(_ string) {
+		_, _ = stdin.Write([]byte(fmt.Sprintf("%v\n", password)))
+		log.Printf("got password prompt, sending password")
+	})
+}
+
 func checkSharedFileContent(t *testing.T, targetfie string, expected string) {
 	f, err := os.Open(fmt.Sprintf("/shared/%v", targetfie))
 	if err != nil {