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package main
import (
"bytes"
"errors"
"io"
"net"
"os"
"path/filepath"
"strconv"
"strings"
"testing"
"golang.org/x/crypto/ssh"
"golang.org/x/crypto/ssh/knownhosts"
)
// genClientKey makes a client key via keygen and returns the private key path
// and the parsed public key.
func genClientKey(t *testing.T) (keyPath string, pub ssh.PublicKey) {
t.Helper()
dir := t.TempDir()
if err := keygen(dir, io.Discard); err != nil {
t.Fatal(err)
}
keyPath = filepath.Join(dir, "id_ed25519")
pb, err := os.ReadFile(filepath.Join(dir, "id_ed25519.pub"))
if err != nil {
t.Fatal(err)
}
pub, _, _, _, err = ssh.ParseAuthorizedKey(pb)
if err != nil {
t.Fatal(err)
}
return keyPath, pub
}
func writeKnownHosts(t *testing.T, host string, port int, hostKey ssh.PublicKey) string {
t.Helper()
addr := knownhosts.Normalize(net.JoinHostPort(host, strconv.Itoa(port)))
line := knownhosts.Line([]string{addr}, hostKey)
p := filepath.Join(t.TempDir(), "known_hosts")
if err := os.WriteFile(p, []byte(line+"\n"), 0o600); err != nil {
t.Fatal(err)
}
return p
}
func setEnv(t *testing.T, key, kh string, port int) {
t.Setenv("RSH_KEY", key)
t.Setenv("RSH_KNOWN_HOSTS", kh)
t.Setenv("RSH_PORT", strconv.Itoa(port))
}
func TestTransportBridgesStdio(t *testing.T) {
keyPath, pub := genClientKey(t)
echo := func(_ string, stdin io.Reader, stdout, _ io.Writer) int {
io.Copy(stdout, stdin)
return 0
}
srv := newTestServer(t, pub, echo)
kh := writeKnownHosts(t, "127.0.0.1", srv.port(), srv.hostKey.PublicKey())
setEnv(t, keyPath, kh, srv.port())
want := []byte("the quick brown fox\x00\x01\x02 binary tail")
var out bytes.Buffer
if err := transport([]string{"-l", "u", "127.0.0.1", "cat"}, bytes.NewReader(want), &out, io.Discard); err != nil {
t.Fatalf("transport: %v", err)
}
if !bytes.Equal(out.Bytes(), want) {
t.Fatalf("bridged data mismatch:\n got %q\nwant %q", out.Bytes(), want)
}
}
func TestTransportKeyFromData(t *testing.T) {
keyPath, pub := genClientKey(t)
echo := func(_ string, stdin io.Reader, stdout, _ io.Writer) int {
io.Copy(stdout, stdin)
return 0
}
srv := newTestServer(t, pub, echo)
kh := writeKnownHosts(t, "127.0.0.1", srv.port(), srv.hostKey.PublicKey())
keyData, err := os.ReadFile(keyPath)
if err != nil {
t.Fatal(err)
}
// RSH_KEY points nowhere; RSH_KEY_DATA must take precedence and work.
t.Setenv("RSH_KEY", "/does/not/exist")
t.Setenv("RSH_KEY_DATA", string(keyData))
t.Setenv("RSH_KNOWN_HOSTS", kh)
t.Setenv("RSH_PORT", strconv.Itoa(srv.port()))
want := []byte("via key data")
var out bytes.Buffer
if err := transport([]string{"-l", "u", "127.0.0.1", "cat"}, bytes.NewReader(want), &out, io.Discard); err != nil {
t.Fatalf("transport: %v", err)
}
if !bytes.Equal(out.Bytes(), want) {
t.Fatalf("bridged data mismatch: %q", out.Bytes())
}
}
func TestTransportRejectsUnknownHostKey(t *testing.T) {
keyPath, pub := genClientKey(t)
srv := newTestServer(t, pub, func(_ string, _ io.Reader, _, _ io.Writer) int { return 0 })
// Pin a DIFFERENT key, so the server's real host key must be rejected.
_, wrong := genClientKey(t)
kh := writeKnownHosts(t, "127.0.0.1", srv.port(), wrong)
setEnv(t, keyPath, kh, srv.port())
if err := transport([]string{"-l", "u", "127.0.0.1", "true"}, bytes.NewReader(nil), io.Discard, io.Discard); err == nil {
t.Fatal("expected host-key mismatch error, got nil")
}
}
func TestTransportPropagatesExitCode(t *testing.T) {
keyPath, pub := genClientKey(t)
srv := newTestServer(t, pub, func(_ string, _ io.Reader, _, _ io.Writer) int { return 7 })
kh := writeKnownHosts(t, "127.0.0.1", srv.port(), srv.hostKey.PublicKey())
setEnv(t, keyPath, kh, srv.port())
err := transport([]string{"-l", "u", "127.0.0.1", "false"}, bytes.NewReader(nil), io.Discard, io.Discard)
var ee *ssh.ExitError
if !errors.As(err, &ee) || ee.ExitStatus() != 7 {
t.Fatalf("expected exit status 7, got %v", err)
}
}
func TestPubkeyMatchesKeygen(t *testing.T) {
keyPath, pub := genClientKey(t)
keyData, err := os.ReadFile(keyPath)
if err != nil {
t.Fatal(err)
}
t.Setenv("RSH_KEY", "")
t.Setenv("RSH_KEY_DATA", string(keyData))
var out bytes.Buffer
if err := pubkey(&out); err != nil {
t.Fatalf("pubkey: %v", err)
}
got, _, _, _, err := ssh.ParseAuthorizedKey(out.Bytes())
if err != nil {
t.Fatalf("parse pubkey output: %v", err)
}
if !bytes.Equal(got.Marshal(), pub.Marshal()) {
t.Fatal("pubkey output does not match the keygen public key")
}
}
func TestPubkeyRejectsMissingKey(t *testing.T) {
t.Setenv("RSH_KEY", "")
t.Setenv("RSH_KEY_DATA", "")
if err := pubkey(io.Discard); err == nil {
t.Fatal("expected error when no key is configured")
}
}
func TestScanPrintsFingerprintAndLine(t *testing.T) {
keyPath, pub := genClientKey(t)
srv := newTestServer(t, pub, func(_ string, _ io.Reader, _, _ io.Writer) int { return 0 })
t.Setenv("RSH_KEY", keyPath)
t.Setenv("RSH_PORT", strconv.Itoa(srv.port()))
var out bytes.Buffer
if err := scan("u@127.0.0.1", &out); err != nil {
t.Fatalf("scan: %v", err)
}
lines := strings.SplitN(strings.TrimSpace(out.String()), "\n", 2)
if len(lines) != 2 {
t.Fatalf("want fingerprint + known_hosts line, got %q", out.String())
}
if !strings.HasPrefix(lines[0], "SHA256:") {
t.Errorf("fingerprint: %q", lines[0])
}
// The printed known_hosts line must validate the real host key.
khPath := filepath.Join(t.TempDir(), "kh")
if err := os.WriteFile(khPath, []byte(lines[1]+"\n"), 0o600); err != nil {
t.Fatal(err)
}
cb, err := knownhosts.New(khPath)
if err != nil {
t.Fatal(err)
}
addr := net.JoinHostPort("127.0.0.1", strconv.Itoa(srv.port()))
remote := &net.TCPAddr{IP: net.IPv4(127, 0, 0, 1), Port: srv.port()}
if err := cb(addr, remote, srv.hostKey.PublicKey()); err != nil {
t.Errorf("pinned line did not validate the host key: %v", err)
}
}
func TestParseTransport(t *testing.T) {
cases := []struct {
args []string
user, host string
cmd string
wantErr bool
}{
{[]string{"-l", "alice", "host", "rsync", "--server"}, "alice", "host", "rsync --server", false},
{[]string{"bob@host", "echo", "hi"}, "bob", "host", "echo hi", false},
{[]string{"-l", "alice", "carol@host", "x"}, "alice", "host", "x", false},
{[]string{"host"}, "", "host", "", false},
{[]string{"-l"}, "", "", "", true},
{[]string{"-p", "22", "host", "x"}, "", "", "", true},
}
for _, c := range cases {
u, h, cmd, err := parseTransport(c.args)
if c.wantErr {
if err == nil {
t.Errorf("%v: expected error", c.args)
}
continue
}
if err != nil {
t.Errorf("%v: %v", c.args, err)
continue
}
if u != c.user || h != c.host || strings.Join(cmd, " ") != c.cmd {
t.Errorf("%v: got (%q,%q,%q) want (%q,%q,%q)",
c.args, u, h, strings.Join(cmd, " "), c.user, c.host, c.cmd)
}
}
}
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