Pull from ecr

generate random user password

Dockerfile

@@ -1,4 +1,5 @@
-FROM golang:1.25-alpine AS builder
+# FROM golang:1.25-alpine AS builder
+FROM public.ecr.aws/docker/library/golang:1.25-alpine AS builder
 
 # Install git and ca-certificates
 RUN apk --no-cache add ca-certificates git tzdata
@@ -18,7 +19,7 @@ COPY . .
 # Build the application
 RUN CGO_ENABLED=0 GOOS=linux go build -ldflags="-s -w" -o /newt
 
-FROM alpine:3.23 AS runner
+FROM public.ecr.aws/docker/library/alpine:3.23 AS runner
 
 RUN apk --no-cache add ca-certificates tzdata iputils
 

authdaemon.go

@@ -46,11 +46,12 @@ func startAuthDaemon(ctx context.Context) error {
 
 	// Create auth daemon server
 	cfg := authdaemon.Config{
-		DisableHTTPS:       true, // We run without HTTP server in newt
+		DisableHTTPS:           true,                   // We run without HTTP server in newt
-		PresharedKey:       "this-key-is-not-used",   // Not used in embedded mode, but set to non-empty to satisfy validation
+		PresharedKey:           "this-key-is-not-used", // Not used in embedded mode, but set to non-empty to satisfy validation
-		PrincipalsFilePath: principalsFile,
+		PrincipalsFilePath:     principalsFile,
-		CACertPath:         caCertPath,
+		CACertPath:             caCertPath,
-		Force:              true,
+		Force:                  true,
+		GenerateRandomPassword: authDaemonGenerateRandomPassword,
 	}
 
 	srv, err := authdaemon.NewServer(cfg)
@@ -72,8 +73,6 @@ func startAuthDaemon(ctx context.Context) error {
 	return nil
 }
 
-
-
 // runPrincipalsCmd executes the principals subcommand logic
 func runPrincipalsCmd(args []string) {
 	opts := struct {
@@ -148,4 +147,4 @@ Example:
   newt principals --username alice
 
 `, defaultPrincipalsPath)
-}
+}

authdaemon/connection.go

@@ -7,8 +7,8 @@ import (
 // ProcessConnection runs the same logic as POST /connection: CA cert, user create/reconcile, principals.
 // Use this when DisableHTTPS is true (e.g. embedded in Newt) instead of calling the API.
 func (s *Server) ProcessConnection(req ConnectionRequest) {
-	logger.Info("connection: niceId=%q username=%q metadata.sudo=%v metadata.homedir=%v",
+	logger.Info("connection: niceId=%q username=%q metadata.sudoMode=%q metadata.sudoCommands=%v metadata.homedir=%v metadata.groups=%v",
-		req.NiceId, req.Username, req.Metadata.Sudo, req.Metadata.Homedir)
+		req.NiceId, req.Username, req.Metadata.SudoMode, req.Metadata.SudoCommands, req.Metadata.Homedir, req.Metadata.Groups)
 
 	cfg := &s.cfg
 	if cfg.CACertPath != "" {
@@ -16,7 +16,7 @@ func (s *Server) ProcessConnection(req ConnectionRequest) {
 			logger.Warn("auth-daemon: write CA cert: %v", err)
 		}
 	}
-	if err := ensureUser(req.Username, req.Metadata); err != nil {
+	if err := ensureUser(req.Username, req.Metadata, s.cfg.GenerateRandomPassword); err != nil {
 		logger.Warn("auth-daemon: ensure user: %v", err)
 	}
 	if cfg.PrincipalsFilePath != "" {

authdaemon/host_linux.go

@@ -4,6 +4,8 @@ package authdaemon
 
 import (
 	"bufio"
+	"crypto/rand"
+	"encoding/hex"
 	"encoding/json"
 	"fmt"
 	"os"
@@ -122,8 +124,73 @@ func sudoGroup() string {
 	return "sudo"
 }
 
+// setRandomPassword generates a random password and sets it for username via chpasswd.
+// Used when GenerateRandomPassword is true so SSH with PermitEmptyPasswords no can accept the user.
+func setRandomPassword(username string) error {
+	b := make([]byte, 16)
+	if _, err := rand.Read(b); err != nil {
+		return fmt.Errorf("generate password: %w", err)
+	}
+	password := hex.EncodeToString(b)
+	cmd := exec.Command("chpasswd")
+	cmd.Stdin = strings.NewReader(username + ":" + password)
+	if out, err := cmd.CombinedOutput(); err != nil {
+		return fmt.Errorf("chpasswd: %w (output: %s)", err, string(out))
+	}
+	return nil
+}
+
+const skelDir = "/etc/skel"
+
+// copySkelInto copies files from srcDir (e.g. /etc/skel) into dstDir (e.g. user's home).
+// Only creates files that don't already exist. All created paths are chowned to uid:gid.
+func copySkelInto(srcDir, dstDir string, uid, gid int) {
+	entries, err := os.ReadDir(srcDir)
+	if err != nil {
+		if !os.IsNotExist(err) {
+			logger.Warn("auth-daemon: read %s: %v", srcDir, err)
+		}
+		return
+	}
+	for _, e := range entries {
+		name := e.Name()
+		src := filepath.Join(srcDir, name)
+		dst := filepath.Join(dstDir, name)
+		if e.IsDir() {
+			if st, err := os.Stat(dst); err == nil && st.IsDir() {
+				copySkelInto(src, dst, uid, gid)
+				continue
+			}
+			if err := os.MkdirAll(dst, 0755); err != nil {
+				logger.Warn("auth-daemon: mkdir %s: %v", dst, err)
+				continue
+			}
+			if err := os.Chown(dst, uid, gid); err != nil {
+				logger.Warn("auth-daemon: chown %s: %v", dst, err)
+			}
+			copySkelInto(src, dst, uid, gid)
+			continue
+		}
+		if _, err := os.Stat(dst); err == nil {
+			continue
+		}
+		data, err := os.ReadFile(src)
+		if err != nil {
+			logger.Warn("auth-daemon: read %s: %v", src, err)
+			continue
+		}
+		if err := os.WriteFile(dst, data, 0644); err != nil {
+			logger.Warn("auth-daemon: write %s: %v", dst, err)
+			continue
+		}
+		if err := os.Chown(dst, uid, gid); err != nil {
+			logger.Warn("auth-daemon: chown %s: %v", dst, err)
+		}
+	}
+}
+
 // ensureUser creates the system user if missing, or reconciles sudo and homedir to match meta.
-func ensureUser(username string, meta ConnectionMetadata) error {
+func ensureUser(username string, meta ConnectionMetadata, generateRandomPassword bool) error {
 	if username == "" {
 		return nil
 	}
@@ -132,12 +199,49 @@ func ensureUser(username string, meta ConnectionMetadata) error {
 		if _, ok := err.(user.UnknownUserError); !ok {
 			return fmt.Errorf("lookup user %s: %w", username, err)
 		}
-		return createUser(username, meta)
+		return createUser(username, meta, generateRandomPassword)
 	}
 	return reconcileUser(u, meta)
 }
 
-func createUser(username string, meta ConnectionMetadata) error {
+// desiredGroups returns the exact list of supplementary groups the user should have:
+// meta.Groups plus the sudo group when meta.SudoMode is "full" (deduped).
+func desiredGroups(meta ConnectionMetadata) []string {
+	seen := make(map[string]struct{})
+	var out []string
+	for _, g := range meta.Groups {
+		g = strings.TrimSpace(g)
+		if g == "" {
+			continue
+		}
+		if _, ok := seen[g]; ok {
+			continue
+		}
+		seen[g] = struct{}{}
+		out = append(out, g)
+	}
+	if meta.SudoMode == "full" {
+		sg := sudoGroup()
+		if _, ok := seen[sg]; !ok {
+			out = append(out, sg)
+		}
+	}
+	return out
+}
+
+// setUserGroups sets the user's supplementary groups to exactly groups (local mirrors metadata).
+// When groups is empty, clears all supplementary groups (usermod -G "").
+func setUserGroups(username string, groups []string) {
+	list := strings.Join(groups, ",")
+	cmd := exec.Command("usermod", "-G", list, username)
+	if out, err := cmd.CombinedOutput(); err != nil {
+		logger.Warn("auth-daemon: usermod -G %s: %v (output: %s)", list, err, string(out))
+	} else {
+		logger.Info("auth-daemon: set %s supplementary groups to %s", username, list)
+	}
+}
+
+func createUser(username string, meta ConnectionMetadata, generateRandomPassword bool) error {
 	args := []string{"-s", "/bin/bash"}
 	if meta.Homedir {
 		args = append(args, "-m")
@@ -150,75 +254,143 @@ func createUser(username string, meta ConnectionMetadata) error {
 		return fmt.Errorf("useradd %s: %w (output: %s)", username, err, string(out))
 	}
 	logger.Info("auth-daemon: created user %s (homedir=%v)", username, meta.Homedir)
-	if meta.Sudo {
+	if generateRandomPassword {
-		group := sudoGroup()
+		if err := setRandomPassword(username); err != nil {
-		cmd := exec.Command("usermod", "-aG", group, username)
+			logger.Warn("auth-daemon: set random password for %s: %v", username, err)
-		if out, err := cmd.CombinedOutput(); err != nil {
-			logger.Warn("auth-daemon: usermod -aG %s %s: %v (output: %s)", group, username, err, string(out))
 		} else {
-			logger.Info("auth-daemon: added %s to %s", username, group)
+			logger.Info("auth-daemon: set random password for %s (PermitEmptyPasswords no)", username)
 		}
 	}
+	if meta.Homedir {
+		if u, err := user.Lookup(username); err == nil && u.HomeDir != "" {
+			uid, gid := mustAtoi(u.Uid), mustAtoi(u.Gid)
+			copySkelInto(skelDir, u.HomeDir, uid, gid)
+		}
+	}
+	setUserGroups(username, desiredGroups(meta))
+	switch meta.SudoMode {
+	case "full":
+		if err := configurePasswordlessSudo(username); err != nil {
+			logger.Warn("auth-daemon: configure passwordless sudo for %s: %v", username, err)
+		}
+	case "commands":
+		if len(meta.SudoCommands) > 0 {
+			if err := configureSudoCommands(username, meta.SudoCommands); err != nil {
+				logger.Warn("auth-daemon: configure sudo commands for %s: %v", username, err)
+			}
+		}
+	default:
+		removeSudoers(username)
+	}
 	return nil
 }
 
+const sudoersFilePrefix = "90-pangolin-"
+
+func sudoersPath(username string) string {
+	return filepath.Join("/etc/sudoers.d", sudoersFilePrefix+username)
+}
+
+// writeSudoersFile writes content to the user's sudoers.d file and validates with visudo.
+func writeSudoersFile(username, content string) error {
+	sudoersFile := sudoersPath(username)
+	tmpFile := sudoersFile + ".tmp"
+	if err := os.WriteFile(tmpFile, []byte(content), 0440); err != nil {
+		return fmt.Errorf("write temp sudoers file: %w", err)
+	}
+	cmd := exec.Command("visudo", "-c", "-f", tmpFile)
+	if out, err := cmd.CombinedOutput(); err != nil {
+		os.Remove(tmpFile)
+		return fmt.Errorf("visudo validation failed: %w (output: %s)", err, string(out))
+	}
+	if err := os.Rename(tmpFile, sudoersFile); err != nil {
+		os.Remove(tmpFile)
+		return fmt.Errorf("move sudoers file: %w", err)
+	}
+	return nil
+}
+
+// configurePasswordlessSudo creates a sudoers.d file to allow passwordless sudo for the user.
+func configurePasswordlessSudo(username string) error {
+	content := fmt.Sprintf("# Created by Pangolin auth-daemon\n%s ALL=(ALL) NOPASSWD:ALL\n", username)
+	if err := writeSudoersFile(username, content); err != nil {
+		return err
+	}
+	logger.Info("auth-daemon: configured passwordless sudo for %s", username)
+	return nil
+}
+
+// configureSudoCommands creates a sudoers.d file allowing only the listed commands (NOPASSWD).
+// Each command should be a full path (e.g. /usr/bin/systemctl).
+func configureSudoCommands(username string, commands []string) error {
+	var b strings.Builder
+	b.WriteString("# Created by Pangolin auth-daemon (restricted commands)\n")
+	n := 0
+	for _, c := range commands {
+		c = strings.TrimSpace(c)
+		if c == "" {
+			continue
+		}
+		fmt.Fprintf(&b, "%s ALL=(ALL) NOPASSWD: %s\n", username, c)
+		n++
+	}
+	if n == 0 {
+		return fmt.Errorf("no valid sudo commands")
+	}
+	if err := writeSudoersFile(username, b.String()); err != nil {
+		return err
+	}
+	logger.Info("auth-daemon: configured restricted sudo for %s (%d commands)", username, len(commands))
+	return nil
+}
+
+// removeSudoers removes the sudoers.d file for the user.
+func removeSudoers(username string) {
+	sudoersFile := sudoersPath(username)
+	if err := os.Remove(sudoersFile); err != nil && !os.IsNotExist(err) {
+		logger.Warn("auth-daemon: remove sudoers for %s: %v", username, err)
+	} else if err == nil {
+		logger.Info("auth-daemon: removed sudoers for %s", username)
+	}
+}
+
 func mustAtoi(s string) int {
 	n, _ := strconv.Atoi(s)
 	return n
 }
 
 func reconcileUser(u *user.User, meta ConnectionMetadata) error {
-	group := sudoGroup()
+	setUserGroups(u.Username, desiredGroups(meta))
-	inGroup, err := userInGroup(u.Username, group)
+	switch meta.SudoMode {
-	if err != nil {
+	case "full":
-		logger.Warn("auth-daemon: check group %s: %v", group, err)
+		if err := configurePasswordlessSudo(u.Username); err != nil {
-		inGroup = false
+			logger.Warn("auth-daemon: configure passwordless sudo for %s: %v", u.Username, err)
-	}
-	if meta.Sudo && !inGroup {
-		cmd := exec.Command("usermod", "-aG", group, u.Username)
-		if out, err := cmd.CombinedOutput(); err != nil {
-			logger.Warn("auth-daemon: usermod -aG %s %s: %v (output: %s)", group, u.Username, err, string(out))
-		} else {
-			logger.Info("auth-daemon: added %s to %s", u.Username, group)
 		}
-	} else if !meta.Sudo && inGroup {
+	case "commands":
-		cmd := exec.Command("gpasswd", "-d", u.Username, group)
+		if len(meta.SudoCommands) > 0 {
-		if out, err := cmd.CombinedOutput(); err != nil {
+			if err := configureSudoCommands(u.Username, meta.SudoCommands); err != nil {
-			logger.Warn("auth-daemon: gpasswd -d %s %s: %v (output: %s)", u.Username, group, err, string(out))
+				logger.Warn("auth-daemon: configure sudo commands for %s: %v", u.Username, err)
+			}
 		} else {
-			logger.Info("auth-daemon: removed %s from %s", u.Username, group)
+			removeSudoers(u.Username)
 		}
+	default:
+		removeSudoers(u.Username)
 	}
 	if meta.Homedir && u.HomeDir != "" {
+		uid, gid := mustAtoi(u.Uid), mustAtoi(u.Gid)
 		if st, err := os.Stat(u.HomeDir); err != nil || !st.IsDir() {
 			if err := os.MkdirAll(u.HomeDir, 0755); err != nil {
 				logger.Warn("auth-daemon: mkdir %s: %v", u.HomeDir, err)
 			} else {
-				uid, gid := mustAtoi(u.Uid), mustAtoi(u.Gid)
 				_ = os.Chown(u.HomeDir, uid, gid)
+				copySkelInto(skelDir, u.HomeDir, uid, gid)
 				logger.Info("auth-daemon: created home %s for %s", u.HomeDir, u.Username)
 			}
+		} else {
+			// Ensure .bashrc etc. exist (e.g. home existed but was empty or skel was minimal)
+			copySkelInto(skelDir, u.HomeDir, uid, gid)
 		}
 	}
 	return nil
 }
-
-func userInGroup(username, groupName string) (bool, error) {
-	// getent group wheel returns "wheel:x:10:user1,user2"
-	cmd := exec.Command("getent", "group", groupName)
-	out, err := cmd.Output()
-	if err != nil {
-		return false, err
-	}
-	parts := strings.SplitN(strings.TrimSpace(string(out)), ":", 4)
-	if len(parts) < 4 {
-		return false, nil
-	}
-	members := strings.Split(parts[3], ",")
-	for _, m := range members {
-		if strings.TrimSpace(m) == username {
-			return true, nil
-		}
-	}
-	return false, nil
-}

authdaemon/host_stub.go

@@ -12,7 +12,7 @@ func writeCACertIfNotExists(path, contents string, force bool) error {
 }
 
 // ensureUser returns an error on non-Linux.
-func ensureUser(username string, meta ConnectionMetadata) error {
+func ensureUser(username string, meta ConnectionMetadata, generateRandomPassword bool) error {
 	return errLinuxOnly
 }
 

authdaemon/routes.go

@@ -13,8 +13,10 @@ func (s *Server) registerRoutes() {
 
 // ConnectionMetadata is the metadata object in POST /connection.
 type ConnectionMetadata struct {
-	Sudo    bool `json:"sudo"`
+	SudoMode     string   `json:"sudoMode"`     // "none" | "full" | "commands"
-	Homedir bool `json:"homedir"`
+	SudoCommands []string `json:"sudoCommands"`  // used when sudoMode is "commands"
+	Homedir      bool     `json:"homedir"`
+	Groups       []string `json:"groups"`        // system groups to add the user to
 }
 
 // ConnectionRequest is the JSON body for POST /connection.

authdaemon/server.go

@@ -27,8 +27,9 @@ type Config struct {
 	Port               int    // Required when DisableHTTPS is false. Listen port for the HTTPS server. No default.
 	PresharedKey       string // Required when DisableHTTPS is false. HTTP auth (Authorization: Bearer <key> or X-Preshared-Key: <key>). No default.
 	CACertPath         string // Required. Where to write the CA cert (e.g. /etc/ssh/ca.pem). No default.
-	Force              bool   // If true, overwrite existing CA cert (and other items) when content differs. Default false.
+	Force                   bool   // If true, overwrite existing CA cert (and other items) when content differs. Default false.
-	PrincipalsFilePath string // Required. Path to the principals data file (JSON: username -> array of principals). No default.
+	PrincipalsFilePath      string // Required. Path to the principals data file (JSON: username -> array of principals). No default.
+	GenerateRandomPassword  bool   // If true, set a random password on users when they are provisioned (for SSH PermitEmptyPasswords no).
 }
 
 type Server struct {

main.go

@@ -116,6 +116,7 @@ var (
 	logLevel                           string
 	interfaceName                      string
 	port                               uint16
+	portStr                            string
 	disableClients                     bool
 	updownScript                       string
 	dockerSocket                       string
@@ -136,6 +137,7 @@ var (
 	authDaemonPrincipalsFile           string
 	authDaemonCACertPath               string
 	authDaemonEnabled                  bool
+	authDaemonGenerateRandomPassword   bool
 	// Build/version (can be overridden via -ldflags "-X main.newtVersion=...")
 	newtVersion = "version_replaceme"
 
@@ -210,11 +212,12 @@ func runNewtMain(ctx context.Context) {
 	logLevel = os.Getenv("LOG_LEVEL")
 	updownScript = os.Getenv("UPDOWN_SCRIPT")
 	interfaceName = os.Getenv("INTERFACE")
-	portStr := os.Getenv("PORT")
+	portStr = os.Getenv("PORT")
 	authDaemonKey = os.Getenv("AD_KEY")
 	authDaemonPrincipalsFile = os.Getenv("AD_PRINCIPALS_FILE")
 	authDaemonCACertPath = os.Getenv("AD_CA_CERT_PATH")
 	authDaemonEnabledEnv := os.Getenv("AUTH_DAEMON_ENABLED")
+	authDaemonGenerateRandomPasswordEnv := os.Getenv("AD_GENERATE_RANDOM_PASSWORD")
 
 	// Metrics/observability env mirrors
 	metricsEnabledEnv := os.Getenv("NEWT_METRICS_PROMETHEUS_ENABLED")
@@ -420,6 +423,13 @@ func runNewtMain(ctx context.Context) {
 			authDaemonEnabled = v
 		}
 	}
+	if authDaemonGenerateRandomPasswordEnv == "" {
+		flag.BoolVar(&authDaemonGenerateRandomPassword, "ad-generate-random-password", false, "Generate a random password for authenticated users")
+	} else {
+		if v, err := strconv.ParseBool(authDaemonGenerateRandomPasswordEnv); err == nil {
+			authDaemonGenerateRandomPassword = v
+		}
+	}
 
 	// do a --version check
 	version := flag.Bool("version", false, "Print the version")
@@ -1378,15 +1388,18 @@ persistent_keepalive_interval=5`, util.FixKey(privateKey.String()), util.FixKey(
 
 		// Define the structure of the incoming message
 		type SSHCertData struct {
-			MessageId int    `json:"messageId"`
+			MessageId          int    `json:"messageId"`
-			AgentPort int    `json:"agentPort"`
+			AgentPort          int    `json:"agentPort"`
-			AgentHost string `json:"agentHost"`
+			AgentHost          string `json:"agentHost"`
-			CACert    string `json:"caCert"`
+			ExternalAuthDaemon bool   `json:"externalAuthDaemon"`
-			Username  string `json:"username"`
+			CACert             string `json:"caCert"`
-			NiceID    string `json:"niceId"`
+			Username           string `json:"username"`
-			Metadata  struct {
+			NiceID             string `json:"niceId"`
-				Sudo    bool `json:"sudo"`
+			Metadata           struct {
-				Homedir bool `json:"homedir"`
+				SudoMode     string   `json:"sudoMode"`
+				SudoCommands []string `json:"sudoCommands"`
+				Homedir      bool     `json:"homedir"`
+				Groups       []string `json:"groups"`
 			} `json:"metadata"`
 		}
 
@@ -1406,7 +1419,7 @@ persistent_keepalive_interval=5`, util.FixKey(privateKey.String()), util.FixKey(
 		}
 
 		// Check if we're running the auth daemon internally
-		if authDaemonServer != nil {
+		if authDaemonServer != nil && !certData.ExternalAuthDaemon { // if the auth daemon is running internally and the external auth daemon is not enabled
 			// Call ProcessConnection directly when running internally
 			logger.Debug("Calling internal auth daemon ProcessConnection for user %s", certData.Username)
 
@@ -1415,8 +1428,10 @@ persistent_keepalive_interval=5`, util.FixKey(privateKey.String()), util.FixKey(
 				NiceId:   certData.NiceID,
 				Username: certData.Username,
 				Metadata: authdaemon.ConnectionMetadata{
-					Sudo:    certData.Metadata.Sudo,
+					SudoMode:     certData.Metadata.SudoMode,
-					Homedir: certData.Metadata.Homedir,
+					SudoCommands: certData.Metadata.SudoCommands,
+					Homedir:      certData.Metadata.Homedir,
+					Groups:       certData.Metadata.Groups,
 				},
 			})
 
@@ -1450,8 +1465,10 @@ persistent_keepalive_interval=5`, util.FixKey(privateKey.String()), util.FixKey(
 				"niceId":   certData.NiceID,
 				"username": certData.Username,
 				"metadata": map[string]interface{}{
-					"sudo":    certData.Metadata.Sudo,
+					"sudoMode":     certData.Metadata.SudoMode,
-					"homedir": certData.Metadata.Homedir,
+					"sudoCommands": certData.Metadata.SudoCommands,
+					"homedir":      certData.Metadata.Homedir,
+					"groups":       certData.Metadata.Groups,
 				},
 			}
 

newt.iss

@@ -32,7 +32,7 @@ DefaultGroupName={#MyAppName}
 DisableProgramGroupPage=yes
 ; Uncomment the following line to run in non administrative install mode (install for current user only).
 ;PrivilegesRequired=lowest
-OutputBaseFilename=mysetup
+OutputBaseFilename=newt_windows_installer
 SolidCompression=yes
 WizardStyle=modern
 ; Add this to ensure PATH changes are applied and the system is prompted for a restart if needed