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23 Commits

Author SHA1 Message Date
Owen Schwartz
1656141599 Merge pull request #245 from fosrl/dev
generate random user password
2026-02-26 20:55:37 -08:00
miloschwartz
1bf89a2cc9 generate random user password 2026-02-26 10:30:24 -08:00
Owen
555e1ddc7c Update iss 2026-02-25 14:57:32 -08:00
Owen
514c94519e Fix port parsing
Fixes #243
2026-02-25 11:52:15 -08:00
Owen Schwartz
1a3eaedfa5 Merge pull request #242 from fosrl/dev
1.10.0
2026-02-22 16:36:25 -08:00
Owen
01e2ba31b7 Merge branch 'main' into dev 2026-02-22 16:36:15 -08:00
miloschwartz
556be90b7e support sudo configuration and daemon mode 2026-02-20 20:42:42 -08:00
Owen
5d04be92f7 Allow sudo passwordless 2026-02-17 22:36:28 -08:00
miloschwartz
b7af49d759 fix flag 2026-02-17 22:10:01 -08:00
Owen
00a5fa1f37 Add daemon into newt 2026-02-17 22:10:01 -08:00
miloschwartz
d256d6c746 remove defaults 2026-02-17 22:10:01 -08:00
miloschwartz
2cc957d55f add auth daemon 2026-02-17 22:10:01 -08:00
Owen
d98eaa88b3 Add round trip tracking for any message 2026-02-17 22:10:01 -08:00
Owen
5b884042cd Add basic newt command relay to auth daemon 2026-02-17 22:10:01 -08:00
Owen
2265b61381 Remove legacy ssh 2026-02-17 22:10:01 -08:00
miloschwartz
60dac98514 fix flag 2026-02-17 21:01:10 -08:00
Owen
759e4c5bac Add daemon into newt 2026-02-17 14:44:28 -08:00
miloschwartz
8609be130e remove defaults 2026-02-16 20:50:13 -08:00
miloschwartz
e06b8de0a7 add auth daemon 2026-02-16 20:36:13 -08:00
Owen
0af6fb8fef Add round trip tracking for any message 2026-02-16 20:29:19 -08:00
Owen
9526768dfe Add basic newt command relay to auth daemon 2026-02-16 20:04:33 -08:00
Owen
051ab6ca9d Remove legacy ssh 2026-02-16 17:55:17 -08:00
Owen
50fbfdc262 Update example domain 2026-02-16 17:54:19 -08:00
11 changed files with 1104 additions and 103 deletions

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@@ -1,5 +1,5 @@
# Copy this file to .env and fill in your values
# Required for connecting to Pangolin service
PANGOLIN_ENDPOINT=https://example.com
PANGOLIN_ENDPOINT=https://app.pangolin.net
NEWT_ID=changeme-id
NEWT_SECRET=changeme-secret

150
authdaemon.go Normal file
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@@ -0,0 +1,150 @@
package main
import (
"context"
"errors"
"fmt"
"os"
"runtime"
"github.com/fosrl/newt/authdaemon"
"github.com/fosrl/newt/logger"
)
const (
defaultPrincipalsPath = "/var/run/auth-daemon/principals"
defaultCACertPath = "/etc/ssh/ca.pem"
)
var (
errPresharedKeyRequired = errors.New("auth-daemon-key is required when --auth-daemon is enabled")
errRootRequired = errors.New("auth-daemon must be run as root (use sudo)")
authDaemonServer *authdaemon.Server // Global auth daemon server instance
)
// startAuthDaemon initializes and starts the auth daemon in the background.
// It validates requirements (Linux, root, preshared key) and starts the server
// in a goroutine so it runs alongside normal newt operation.
func startAuthDaemon(ctx context.Context) error {
// Validation
if runtime.GOOS != "linux" {
return fmt.Errorf("auth-daemon is only supported on Linux, not %s", runtime.GOOS)
}
if os.Geteuid() != 0 {
return errRootRequired
}
// Use defaults if not set
principalsFile := authDaemonPrincipalsFile
if principalsFile == "" {
principalsFile = defaultPrincipalsPath
}
caCertPath := authDaemonCACertPath
if caCertPath == "" {
caCertPath = defaultCACertPath
}
// Create auth daemon server
cfg := authdaemon.Config{
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
PrincipalsFilePath: principalsFile,
CACertPath: caCertPath,
Force: true,
GenerateRandomPassword: authDaemonGenerateRandomPassword,
}
srv, err := authdaemon.NewServer(cfg)
if err != nil {
return fmt.Errorf("create auth daemon server: %w", err)
}
authDaemonServer = srv
// Start the auth daemon in a goroutine so it runs alongside newt
go func() {
logger.Info("Auth daemon starting (native mode, no HTTP server)")
if err := srv.Run(ctx); err != nil {
logger.Error("Auth daemon error: %v", err)
}
logger.Info("Auth daemon stopped")
}()
return nil
}
// runPrincipalsCmd executes the principals subcommand logic
func runPrincipalsCmd(args []string) {
opts := struct {
PrincipalsFile string
Username string
}{
PrincipalsFile: defaultPrincipalsPath,
}
// Parse flags manually
for i := 0; i < len(args); i++ {
switch args[i] {
case "--principals-file":
if i+1 >= len(args) {
fmt.Fprintf(os.Stderr, "Error: --principals-file requires a value\n")
os.Exit(1)
}
opts.PrincipalsFile = args[i+1]
i++
case "--username":
if i+1 >= len(args) {
fmt.Fprintf(os.Stderr, "Error: --username requires a value\n")
os.Exit(1)
}
opts.Username = args[i+1]
i++
case "--help", "-h":
printPrincipalsHelp()
os.Exit(0)
default:
fmt.Fprintf(os.Stderr, "Error: unknown flag: %s\n", args[i])
printPrincipalsHelp()
os.Exit(1)
}
}
// Validation
if opts.Username == "" {
fmt.Fprintf(os.Stderr, "Error: username is required\n")
printPrincipalsHelp()
os.Exit(1)
}
// Get principals
list, err := authdaemon.GetPrincipals(opts.PrincipalsFile, opts.Username)
if err != nil {
fmt.Fprintf(os.Stderr, "Error: %v\n", err)
os.Exit(1)
}
if len(list) == 0 {
fmt.Println("")
return
}
for _, principal := range list {
fmt.Println(principal)
}
}
func printPrincipalsHelp() {
fmt.Fprintf(os.Stderr, `Usage: newt principals [flags]
Output principals for a username (for AuthorizedPrincipalsCommand in sshd_config).
Read the principals file and print principals that match the given username, one per line.
Configure in sshd_config with AuthorizedPrincipalsCommand and %%u for the username.
Flags:
--principals-file string Path to the principals file (default "%s")
--username string Username to look up (required)
--help, -h Show this help message
Example:
newt principals --username alice
`, defaultPrincipalsPath)
}

27
authdaemon/connection.go Normal file
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@@ -0,0 +1,27 @@
package authdaemon
import (
"github.com/fosrl/newt/logger"
)
// 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.sudoMode=%q metadata.sudoCommands=%v metadata.homedir=%v metadata.groups=%v",
req.NiceId, req.Username, req.Metadata.SudoMode, req.Metadata.SudoCommands, req.Metadata.Homedir, req.Metadata.Groups)
cfg := &s.cfg
if cfg.CACertPath != "" {
if err := writeCACertIfNotExists(cfg.CACertPath, req.CaCert, cfg.Force); err != nil {
logger.Warn("auth-daemon: write CA cert: %v", err)
}
}
if err := ensureUser(req.Username, req.Metadata, s.cfg.GenerateRandomPassword); err != nil {
logger.Warn("auth-daemon: ensure user: %v", err)
}
if cfg.PrincipalsFilePath != "" {
if err := writePrincipals(cfg.PrincipalsFilePath, req.Username, req.NiceId); err != nil {
logger.Warn("auth-daemon: write principals: %v", err)
}
}
}

396
authdaemon/host_linux.go Normal file
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@@ -0,0 +1,396 @@
//go:build linux
package authdaemon
import (
"bufio"
"crypto/rand"
"encoding/hex"
"encoding/json"
"fmt"
"os"
"os/exec"
"os/user"
"path/filepath"
"strconv"
"strings"
"github.com/fosrl/newt/logger"
)
// writeCACertIfNotExists writes contents to path. If the file already exists: when force is false, skip; when force is true, overwrite only if content differs.
func writeCACertIfNotExists(path, contents string, force bool) error {
contents = strings.TrimSpace(contents)
if contents != "" && !strings.HasSuffix(contents, "\n") {
contents += "\n"
}
existing, err := os.ReadFile(path)
if err == nil {
existingStr := strings.TrimSpace(string(existing))
if existingStr != "" && !strings.HasSuffix(existingStr, "\n") {
existingStr += "\n"
}
if existingStr == contents {
logger.Debug("auth-daemon: CA cert unchanged at %s, skipping write", path)
return nil
}
if !force {
logger.Debug("auth-daemon: CA cert already exists at %s, skipping write (Force disabled)", path)
return nil
}
} else if !os.IsNotExist(err) {
return fmt.Errorf("read %s: %w", path, err)
}
dir := filepath.Dir(path)
if err := os.MkdirAll(dir, 0755); err != nil {
return fmt.Errorf("mkdir %s: %w", dir, err)
}
if err := os.WriteFile(path, []byte(contents), 0644); err != nil {
return fmt.Errorf("write CA cert: %w", err)
}
logger.Info("auth-daemon: wrote CA cert to %s", path)
return nil
}
// writePrincipals updates the principals file at path: JSON object keyed by username, value is array of principals. Adds username and niceId to that user's list (deduped).
func writePrincipals(path, username, niceId string) error {
if path == "" {
return nil
}
username = strings.TrimSpace(username)
niceId = strings.TrimSpace(niceId)
if username == "" {
return nil
}
data := make(map[string][]string)
if raw, err := os.ReadFile(path); err == nil {
_ = json.Unmarshal(raw, &data)
}
list := data[username]
seen := make(map[string]struct{}, len(list)+2)
for _, p := range list {
seen[p] = struct{}{}
}
for _, p := range []string{username, niceId} {
if p == "" {
continue
}
if _, ok := seen[p]; !ok {
seen[p] = struct{}{}
list = append(list, p)
}
}
data[username] = list
body, err := json.Marshal(data)
if err != nil {
return fmt.Errorf("marshal principals: %w", err)
}
dir := filepath.Dir(path)
if err := os.MkdirAll(dir, 0755); err != nil {
return fmt.Errorf("mkdir %s: %w", dir, err)
}
if err := os.WriteFile(path, body, 0644); err != nil {
return fmt.Errorf("write principals: %w", err)
}
logger.Debug("auth-daemon: wrote principals to %s", path)
return nil
}
// sudoGroup returns the name of the sudo group (wheel or sudo) that exists on the system. Prefers wheel.
func sudoGroup() string {
f, err := os.Open("/etc/group")
if err != nil {
return "sudo"
}
defer f.Close()
sc := bufio.NewScanner(f)
hasWheel := false
hasSudo := false
for sc.Scan() {
line := sc.Text()
if strings.HasPrefix(line, "wheel:") {
hasWheel = true
}
if strings.HasPrefix(line, "sudo:") {
hasSudo = true
}
}
if hasWheel {
return "wheel"
}
if hasSudo {
return "sudo"
}
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, generateRandomPassword bool) error {
if username == "" {
return nil
}
u, err := user.Lookup(username)
if err != nil {
if _, ok := err.(user.UnknownUserError); !ok {
return fmt.Errorf("lookup user %s: %w", username, err)
}
return createUser(username, meta, generateRandomPassword)
}
return reconcileUser(u, meta)
}
// 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")
} else {
args = append(args, "-M")
}
args = append(args, username)
cmd := exec.Command("useradd", args...)
if out, err := cmd.CombinedOutput(); err != nil {
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 generateRandomPassword {
if err := setRandomPassword(username); err != nil {
logger.Warn("auth-daemon: set random password for %s: %v", username, err)
} else {
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 {
setUserGroups(u.Username, desiredGroups(meta))
switch meta.SudoMode {
case "full":
if err := configurePasswordlessSudo(u.Username); err != nil {
logger.Warn("auth-daemon: configure passwordless sudo for %s: %v", u.Username, err)
}
case "commands":
if len(meta.SudoCommands) > 0 {
if err := configureSudoCommands(u.Username, meta.SudoCommands); err != nil {
logger.Warn("auth-daemon: configure sudo commands for %s: %v", u.Username, err)
}
} else {
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 {
_ = 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
}

22
authdaemon/host_stub.go Normal file
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@@ -0,0 +1,22 @@
//go:build !linux
package authdaemon
import "fmt"
var errLinuxOnly = fmt.Errorf("auth-daemon PAM agent is only supported on Linux")
// writeCACertIfNotExists returns an error on non-Linux.
func writeCACertIfNotExists(path, contents string, force bool) error {
return errLinuxOnly
}
// ensureUser returns an error on non-Linux.
func ensureUser(username string, meta ConnectionMetadata, generateRandomPassword bool) error {
return errLinuxOnly
}
// writePrincipals returns an error on non-Linux.
func writePrincipals(path, username, niceId string) error {
return errLinuxOnly
}

28
authdaemon/principals.go Normal file
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@@ -0,0 +1,28 @@
package authdaemon
import (
"encoding/json"
"fmt"
"os"
)
// GetPrincipals reads the principals data file at path, looks up the given user, and returns that user's principals as a string slice.
// The file format is JSON: object with username keys and array-of-principals values, e.g. {"alice":["alice","usr-123"],"bob":["bob","usr-456"]}.
// If the user is not found or the file is missing, returns nil and nil.
func GetPrincipals(path, user string) ([]string, error) {
if path == "" {
return nil, fmt.Errorf("principals file path is required")
}
data, err := os.ReadFile(path)
if err != nil {
if os.IsNotExist(err) {
return nil, nil
}
return nil, fmt.Errorf("read principals file: %w", err)
}
var m map[string][]string
if err := json.Unmarshal(data, &m); err != nil {
return nil, fmt.Errorf("parse principals file: %w", err)
}
return m[user], nil
}

58
authdaemon/routes.go Normal file
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@@ -0,0 +1,58 @@
package authdaemon
import (
"encoding/json"
"net/http"
)
// registerRoutes registers all API routes. Add new endpoints here.
func (s *Server) registerRoutes() {
s.mux.HandleFunc("/health", s.handleHealth)
s.mux.HandleFunc("/connection", s.handleConnection)
}
// ConnectionMetadata is the metadata object in POST /connection.
type ConnectionMetadata struct {
SudoMode string `json:"sudoMode"` // "none" | "full" | "commands"
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.
type ConnectionRequest struct {
CaCert string `json:"caCert"`
NiceId string `json:"niceId"`
Username string `json:"username"`
Metadata ConnectionMetadata `json:"metadata"`
}
// healthResponse is the JSON body for GET /health.
type healthResponse struct {
Status string `json:"status"`
}
// handleHealth responds with 200 and {"status":"ok"}.
func (s *Server) handleHealth(w http.ResponseWriter, r *http.Request) {
if r.Method != http.MethodGet {
http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
return
}
w.Header().Set("Content-Type", "application/json")
_ = json.NewEncoder(w).Encode(healthResponse{Status: "ok"})
}
// handleConnection accepts POST with connection payload and delegates to ProcessConnection.
func (s *Server) handleConnection(w http.ResponseWriter, r *http.Request) {
if r.Method != http.MethodPost {
http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
return
}
var req ConnectionRequest
if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
http.Error(w, "Bad Request", http.StatusBadRequest)
return
}
s.ProcessConnection(req)
w.WriteHeader(http.StatusOK)
}

180
authdaemon/server.go Normal file
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@@ -0,0 +1,180 @@
package authdaemon
import (
"context"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rand"
"crypto/subtle"
"crypto/tls"
"crypto/x509"
"crypto/x509/pkix"
"encoding/pem"
"fmt"
"math/big"
"net/http"
"os"
"runtime"
"strings"
"time"
"github.com/fosrl/newt/logger"
)
type Config struct {
// DisableHTTPS: when true, Run() does not start the HTTPS server (for embedded use inside Newt). Call ProcessConnection directly for connection events.
DisableHTTPS bool
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.
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 {
cfg Config
addr string
presharedKey string
mux *http.ServeMux
tlsCert tls.Certificate
}
// generateTLSCert creates a self-signed certificate and key in memory (no disk).
func generateTLSCert() (tls.Certificate, error) {
key, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
if err != nil {
return tls.Certificate{}, fmt.Errorf("generate key: %w", err)
}
serial, err := rand.Int(rand.Reader, new(big.Int).Lsh(big.NewInt(1), 128))
if err != nil {
return tls.Certificate{}, fmt.Errorf("serial: %w", err)
}
tmpl := &x509.Certificate{
SerialNumber: serial,
Subject: pkix.Name{
CommonName: "localhost",
},
NotBefore: time.Now(),
NotAfter: time.Now().Add(365 * 24 * time.Hour),
KeyUsage: x509.KeyUsageDigitalSignature,
ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
BasicConstraintsValid: true,
DNSNames: []string{"localhost", "127.0.0.1"},
}
certDER, err := x509.CreateCertificate(rand.Reader, tmpl, tmpl, key.Public(), key)
if err != nil {
return tls.Certificate{}, fmt.Errorf("create certificate: %w", err)
}
keyDER, err := x509.MarshalECPrivateKey(key)
if err != nil {
return tls.Certificate{}, fmt.Errorf("marshal key: %w", err)
}
certPEM := pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: certDER})
keyPEM := pem.EncodeToMemory(&pem.Block{Type: "EC PRIVATE KEY", Bytes: keyDER})
cert, err := tls.X509KeyPair(certPEM, keyPEM)
if err != nil {
return tls.Certificate{}, fmt.Errorf("x509 key pair: %w", err)
}
return cert, nil
}
// authMiddleware wraps next and requires a valid preshared key on every request.
// Accepts Authorization: Bearer <key> or X-Preshared-Key: <key>.
func (s *Server) authMiddleware(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
key := ""
if v := r.Header.Get("Authorization"); strings.HasPrefix(v, "Bearer ") {
key = strings.TrimSpace(strings.TrimPrefix(v, "Bearer "))
}
if key == "" {
key = strings.TrimSpace(r.Header.Get("X-Preshared-Key"))
}
if key == "" || subtle.ConstantTimeCompare([]byte(key), []byte(s.presharedKey)) != 1 {
http.Error(w, "Unauthorized", http.StatusUnauthorized)
return
}
next.ServeHTTP(w, r)
})
}
// NewServer builds a new auth-daemon server from cfg. Port, PresharedKey, CACertPath, and PrincipalsFilePath are required (no defaults).
func NewServer(cfg Config) (*Server, error) {
if runtime.GOOS != "linux" {
return nil, fmt.Errorf("auth-daemon is only supported on Linux, not %s", runtime.GOOS)
}
if !cfg.DisableHTTPS {
if cfg.Port <= 0 {
return nil, fmt.Errorf("port is required and must be positive")
}
if cfg.PresharedKey == "" {
return nil, fmt.Errorf("preshared key is required")
}
}
if cfg.CACertPath == "" {
return nil, fmt.Errorf("CACertPath is required")
}
if cfg.PrincipalsFilePath == "" {
return nil, fmt.Errorf("PrincipalsFilePath is required")
}
s := &Server{cfg: cfg}
if !cfg.DisableHTTPS {
cert, err := generateTLSCert()
if err != nil {
return nil, err
}
s.addr = fmt.Sprintf(":%d", cfg.Port)
s.presharedKey = cfg.PresharedKey
s.mux = http.NewServeMux()
s.tlsCert = cert
s.registerRoutes()
}
return s, nil
}
// Run starts the HTTPS server (unless DisableHTTPS) and blocks until ctx is cancelled or the server errors.
// When DisableHTTPS is true, Run() blocks on ctx only and does not listen; use ProcessConnection for connection events.
func (s *Server) Run(ctx context.Context) error {
if s.cfg.DisableHTTPS {
logger.Info("auth-daemon running (HTTPS disabled)")
<-ctx.Done()
s.cleanupPrincipalsFile()
return nil
}
tcfg := &tls.Config{
Certificates: []tls.Certificate{s.tlsCert},
MinVersion: tls.VersionTLS12,
}
handler := s.authMiddleware(s.mux)
srv := &http.Server{
Addr: s.addr,
Handler: handler,
TLSConfig: tcfg,
ReadTimeout: 10 * time.Second,
WriteTimeout: 10 * time.Second,
ReadHeaderTimeout: 5 * time.Second,
IdleTimeout: 60 * time.Second,
}
go func() {
<-ctx.Done()
shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
defer cancel()
if err := srv.Shutdown(shutdownCtx); err != nil {
logger.Warn("auth-daemon shutdown: %v", err)
}
}()
logger.Info("auth-daemon listening on https://127.0.0.1%s", s.addr)
if err := srv.ListenAndServeTLS("", ""); err != nil && err != http.ErrServerClosed {
return err
}
s.cleanupPrincipalsFile()
return nil
}
func (s *Server) cleanupPrincipalsFile() {
if s.cfg.PrincipalsFilePath != "" {
if err := os.Remove(s.cfg.PrincipalsFilePath); err != nil && !os.IsNotExist(err) {
logger.Warn("auth-daemon: remove principals file: %v", err)
}
}
}

View File

@@ -4,7 +4,7 @@ services:
container_name: newt
restart: unless-stopped
environment:
- PANGOLIN_ENDPOINT=https://example.com
- PANGOLIN_ENDPOINT=https://app.pangolin.net
- NEWT_ID=2ix2t8xk22ubpfy
- NEWT_SECRET=nnisrfsdfc7prqsp9ewo1dvtvci50j5uiqotez00dgap0ii2
- LOG_LEVEL=DEBUG

340
main.go
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@@ -1,7 +1,9 @@
package main
import (
"bytes"
"context"
"crypto/tls"
"encoding/json"
"errors"
"flag"
@@ -11,12 +13,12 @@ import (
"net/netip"
"os"
"os/signal"
"path/filepath"
"strconv"
"strings"
"syscall"
"time"
"github.com/fosrl/newt/authdaemon"
"github.com/fosrl/newt/docker"
"github.com/fosrl/newt/healthcheck"
"github.com/fosrl/newt/logger"
@@ -58,10 +60,6 @@ type ExitNodeData struct {
ExitNodes []ExitNode `json:"exitNodes"`
}
type SSHPublicKeyData struct {
PublicKey string `json:"publicKey"`
}
// ExitNode represents an exit node with an ID, endpoint, and weight.
type ExitNode struct {
ID int `json:"exitNodeId"`
@@ -118,6 +116,7 @@ var (
logLevel string
interfaceName string
port uint16
portStr string
disableClients bool
updownScript string
dockerSocket string
@@ -134,6 +133,11 @@ var (
preferEndpoint string
healthMonitor *healthcheck.Monitor
enforceHealthcheckCert bool
authDaemonKey string
authDaemonPrincipalsFile string
authDaemonCACertPath string
authDaemonEnabled bool
authDaemonGenerateRandomPassword bool
// Build/version (can be overridden via -ldflags "-X main.newtVersion=...")
newtVersion = "version_replaceme"
@@ -156,6 +160,28 @@ var (
)
func main() {
// Check for subcommands first (only principals exits early)
if len(os.Args) > 1 {
switch os.Args[1] {
case "auth-daemon":
// Run principals subcommand only if the next argument is "principals"
if len(os.Args) > 2 && os.Args[2] == "principals" {
runPrincipalsCmd(os.Args[3:])
return
}
// auth-daemon subcommand without "principals" - show help
fmt.Println("Error: auth-daemon subcommand requires 'principals' argument")
fmt.Println()
fmt.Println("Usage:")
fmt.Println(" newt auth-daemon principals [options]")
fmt.Println()
// If not "principals", exit the switch to continue with normal execution
return
}
}
// Check if we're running as a Windows service
if isWindowsService() {
runService("NewtWireguardService", false, os.Args[1:])
@@ -186,7 +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")
@@ -279,10 +310,6 @@ func runNewtMain(ctx context.Context) {
// load the prefer endpoint just as a flag
flag.StringVar(&preferEndpoint, "prefer-endpoint", "", "Prefer this endpoint for the connection (if set, will override the endpoint from the server)")
// if authorizedKeysFile == "" {
// flag.StringVar(&authorizedKeysFile, "authorized-keys-file", "~/.ssh/authorized_keys", "Path to authorized keys file (if unset, no keys will be authorized)")
// }
// Add new mTLS flags
if tlsClientCert == "" {
flag.StringVar(&tlsClientCert, "tls-client-cert-file", "", "Path to client certificate file (PEM/DER format)")
@@ -379,6 +406,31 @@ func runNewtMain(ctx context.Context) {
region = regionEnv
}
// Auth daemon flags
if authDaemonKey == "" {
flag.StringVar(&authDaemonKey, "ad-pre-shared-key", "", "Pre-shared key for auth daemon authentication")
}
if authDaemonPrincipalsFile == "" {
flag.StringVar(&authDaemonPrincipalsFile, "ad-principals-file", "/var/run/auth-daemon/principals", "Path to the principals file for auth daemon")
}
if authDaemonCACertPath == "" {
flag.StringVar(&authDaemonCACertPath, "ad-ca-cert-path", "/etc/ssh/ca.pem", "Path to the CA certificate file for auth daemon")
}
if authDaemonEnabledEnv == "" {
flag.BoolVar(&authDaemonEnabled, "auth-daemon", false, "Enable auth daemon mode (runs alongside normal newt operation)")
} else {
if v, err := strconv.ParseBool(authDaemonEnabledEnv); err == nil {
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")
@@ -398,6 +450,13 @@ func runNewtMain(ctx context.Context) {
logger.Init(nil)
loggerLevel := util.ParseLogLevel(logLevel)
// Start auth daemon if enabled
if authDaemonEnabled {
if err := startAuthDaemon(ctx); err != nil {
logger.Fatal("Failed to start auth daemon: %v", err)
}
}
logger.GetLogger().SetLevel(loggerLevel)
// Initialize telemetry after flags are parsed (so flags override env)
@@ -694,8 +753,8 @@ func runNewtMain(ctx context.Context) {
relayPort := wgData.RelayPort
if relayPort == 0 {
relayPort = 21820
}
relayPort = 21820
}
clientsHandleNewtConnection(wgData.PublicKey, endpoint, relayPort)
@@ -1168,94 +1227,6 @@ persistent_keepalive_interval=5`, util.FixKey(privateKey.String()), util.FixKey(
}
})
// EXPERIMENTAL: WHAT SHOULD WE DO ABOUT SECURITY?
client.RegisterHandler("newt/send/ssh/publicKey", func(msg websocket.WSMessage) {
logger.Debug("Received SSH public key request")
var sshPublicKeyData SSHPublicKeyData
jsonData, err := json.Marshal(msg.Data)
if err != nil {
logger.Info(fmtErrMarshaling, err)
return
}
if err := json.Unmarshal(jsonData, &sshPublicKeyData); err != nil {
logger.Info("Error unmarshaling SSH public key data: %v", err)
return
}
sshPublicKey := sshPublicKeyData.PublicKey
if authorizedKeysFile == "" {
logger.Debug("No authorized keys file set, skipping public key response")
return
}
// Expand tilde to home directory if present
expandedPath := authorizedKeysFile
if strings.HasPrefix(authorizedKeysFile, "~/") {
homeDir, err := os.UserHomeDir()
if err != nil {
logger.Error("Failed to get user home directory: %v", err)
return
}
expandedPath = filepath.Join(homeDir, authorizedKeysFile[2:])
}
// if it is set but the file does not exist, create it
if _, err := os.Stat(expandedPath); os.IsNotExist(err) {
logger.Debug("Authorized keys file does not exist, creating it: %s", expandedPath)
if err := os.MkdirAll(filepath.Dir(expandedPath), 0755); err != nil {
logger.Error("Failed to create directory for authorized keys file: %v", err)
return
}
if _, err := os.Create(expandedPath); err != nil {
logger.Error("Failed to create authorized keys file: %v", err)
return
}
}
// Check if the public key already exists in the file
fileContent, err := os.ReadFile(expandedPath)
if err != nil {
logger.Error("Failed to read authorized keys file: %v", err)
return
}
// Check if the key already exists (trim whitespace for comparison)
existingKeys := strings.Split(string(fileContent), "\n")
keyAlreadyExists := false
trimmedNewKey := strings.TrimSpace(sshPublicKey)
for _, existingKey := range existingKeys {
if strings.TrimSpace(existingKey) == trimmedNewKey && trimmedNewKey != "" {
keyAlreadyExists = true
break
}
}
if keyAlreadyExists {
logger.Info("SSH public key already exists in authorized keys file, skipping")
return
}
// append the public key to the authorized keys file
logger.Debug("Appending public key to authorized keys file: %s", sshPublicKey)
file, err := os.OpenFile(expandedPath, os.O_APPEND|os.O_WRONLY, 0644)
if err != nil {
logger.Error("Failed to open authorized keys file: %v", err)
return
}
defer file.Close()
if _, err := file.WriteString(sshPublicKey + "\n"); err != nil {
logger.Error("Failed to write public key to authorized keys file: %v", err)
return
}
logger.Info("SSH public key appended to authorized keys file")
})
// Register handler for adding health check targets
client.RegisterHandler("newt/healthcheck/add", func(msg websocket.WSMessage) {
logger.Debug("Received health check add request: %+v", msg)
@@ -1411,6 +1382,175 @@ persistent_keepalive_interval=5`, util.FixKey(privateKey.String()), util.FixKey(
}
})
// Register handler for SSH certificate issued events
client.RegisterHandler("newt/pam/connection", func(msg websocket.WSMessage) {
logger.Debug("Received SSH certificate issued message")
// Define the structure of the incoming message
type SSHCertData struct {
MessageId int `json:"messageId"`
AgentPort int `json:"agentPort"`
AgentHost string `json:"agentHost"`
ExternalAuthDaemon bool `json:"externalAuthDaemon"`
CACert string `json:"caCert"`
Username string `json:"username"`
NiceID string `json:"niceId"`
Metadata struct {
SudoMode string `json:"sudoMode"`
SudoCommands []string `json:"sudoCommands"`
Homedir bool `json:"homedir"`
Groups []string `json:"groups"`
} `json:"metadata"`
}
var certData SSHCertData
jsonData, err := json.Marshal(msg.Data)
if err != nil {
logger.Error("Error marshaling SSH cert data: %v", err)
return
}
// print the received data for debugging
logger.Debug("Received SSH cert data: %s", string(jsonData))
if err := json.Unmarshal(jsonData, &certData); err != nil {
logger.Error("Error unmarshaling SSH cert data: %v", err)
return
}
// Check if we're running the auth daemon internally
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)
authDaemonServer.ProcessConnection(authdaemon.ConnectionRequest{
CaCert: certData.CACert,
NiceId: certData.NiceID,
Username: certData.Username,
Metadata: authdaemon.ConnectionMetadata{
SudoMode: certData.Metadata.SudoMode,
SudoCommands: certData.Metadata.SudoCommands,
Homedir: certData.Metadata.Homedir,
Groups: certData.Metadata.Groups,
},
})
// Send success response back to cloud
err = client.SendMessage("ws/round-trip/complete", map[string]interface{}{
"messageId": certData.MessageId,
"complete": true,
})
logger.Info("Successfully processed connection via internal auth daemon for user %s", certData.Username)
} else {
// External auth daemon mode - make HTTP request
// Check if auth daemon key is configured
if authDaemonKey == "" {
logger.Error("Auth daemon key not configured, cannot communicate with daemon")
// Send failure response back to cloud
err := client.SendMessage("ws/round-trip/complete", map[string]interface{}{
"messageId": certData.MessageId,
"complete": true,
"error": "auth daemon key not configured",
})
if err != nil {
logger.Error("Failed to send SSH cert failure response: %v", err)
}
return
}
// Prepare the request body for the auth daemon
requestBody := map[string]interface{}{
"caCert": certData.CACert,
"niceId": certData.NiceID,
"username": certData.Username,
"metadata": map[string]interface{}{
"sudoMode": certData.Metadata.SudoMode,
"sudoCommands": certData.Metadata.SudoCommands,
"homedir": certData.Metadata.Homedir,
"groups": certData.Metadata.Groups,
},
}
requestJSON, err := json.Marshal(requestBody)
if err != nil {
logger.Error("Failed to marshal auth daemon request: %v", err)
// Send failure response
client.SendMessage("ws/round-trip/complete", map[string]interface{}{
"messageId": certData.MessageId,
"complete": true,
"error": fmt.Sprintf("failed to marshal request: %v", err),
})
return
}
// Create HTTPS client that skips certificate verification
// (auth daemon uses self-signed cert)
httpClient := &http.Client{
Transport: &http.Transport{
TLSClientConfig: &tls.Config{
InsecureSkipVerify: true,
},
},
Timeout: 10 * time.Second,
}
// Make the request to the auth daemon
url := fmt.Sprintf("https://%s:%d/connection", certData.AgentHost, certData.AgentPort)
req, err := http.NewRequest("POST", url, bytes.NewBuffer(requestJSON))
if err != nil {
logger.Error("Failed to create auth daemon request: %v", err)
client.SendMessage("ws/round-trip/complete", map[string]interface{}{
"messageId": certData.MessageId,
"complete": true,
"error": fmt.Sprintf("failed to create request: %v", err),
})
return
}
// Set headers
req.Header.Set("Content-Type", "application/json")
req.Header.Set("Authorization", "Bearer "+authDaemonKey)
logger.Debug("Sending SSH cert to auth daemon at %s", url)
// Send the request
resp, err := httpClient.Do(req)
if err != nil {
logger.Error("Failed to connect to auth daemon: %v", err)
client.SendMessage("ws/round-trip/complete", map[string]interface{}{
"messageId": certData.MessageId,
"complete": true,
"error": fmt.Sprintf("failed to connect to auth daemon: %v", err),
})
return
}
defer resp.Body.Close()
// Check response status
if resp.StatusCode != http.StatusOK {
logger.Error("Auth daemon returned non-OK status: %d", resp.StatusCode)
client.SendMessage("ws/round-trip/complete", map[string]interface{}{
"messageId": certData.MessageId,
"complete": true,
"error": fmt.Sprintf("auth daemon returned status %d", resp.StatusCode),
})
return
}
logger.Info("Successfully registered SSH certificate with external auth daemon for user %s", certData.Username)
}
// Send success response back to cloud
err = client.SendMessage("ws/round-trip/complete", map[string]interface{}{
"messageId": certData.MessageId,
"complete": true,
})
if err != nil {
logger.Error("Failed to send SSH cert success response: %v", err)
}
})
client.OnConnect(func() error {
publicKey = privateKey.PublicKey()
logger.Debug("Public key: %s", publicKey)

View File

@@ -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