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|
package main
import (
"crypto/tls"
"crypto/x509"
"encoding/pem"
"encoding/xml"
"fmt"
"io"
"net"
"net/textproto"
"net/url"
"os"
"strings"
"time"
)
type xmppStreamsFeatures struct {
XMLName xml.Name `xml:"http://etherx.jabber.org/streams features"`
}
type xmppTlsProceed struct {
XMLName xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-tls proceed"`
}
func xmppStartTLS(connRaw net.Conn, host string) error {
decoder := xml.NewDecoder(connRaw)
// send <stream> start
_, err := fmt.Fprintf(connRaw, "<stream:stream xmlns='jabber:client' xmlns:stream='http://etherx.jabber.org/streams' to='%s' version='1.0'>", host)
if err != nil {
return err
}
// read <stream> start
for {
t, err := decoder.Token()
if err != nil || t == nil {
return err
}
if se, ok := t.(xml.StartElement); ok {
if se.Name.Local != "stream" {
return xml.UnmarshalError(fmt.Sprintf("expected element of type <%s> but have <%s>", "stream", se.Name.Local))
}
break
}
}
// read <features>
var features xmppStreamsFeatures
err = decoder.DecodeElement(&features, nil)
if err != nil {
return err
}
// send <starttls>
_, err = io.WriteString(connRaw, "<starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>")
if err != nil {
return err
}
// read <proceed>
var proceed xmppTlsProceed
err = decoder.DecodeElement(&proceed, nil)
if err != nil {
return err
}
return nil
}
// smtpCmd is a convenience function that sends a command, and reads
// (but discards) the response
func smtpCmd(tp *textproto.Conn, expectCode int, format string, args ...interface{}) error {
id, err := tp.Cmd(format, args...)
if err != nil {
return err
}
tp.StartResponse(id)
defer tp.EndResponse(id)
_, _, err = tp.ReadResponse(expectCode)
return err
}
func smtpStartTLS(connRaw net.Conn, host string) error {
tp := textproto.NewConn(connRaw)
// let the server introduce itself
_, _, err := tp.ReadResponse(220)
if err != nil {
return err
}
// introduce ourself
localhost, err := os.Hostname()
if err != nil {
localhost = "localhost"
}
err = smtpCmd(tp, 250, "EHLO %s", localhost)
if err != nil {
err := smtpCmd(tp, 250, "HELO %s", localhost)
if err != nil {
return err
}
}
// starttls
err = smtpCmd(tp, 220, "STARTTLS")
if err != nil {
return err
}
return nil
}
func getcert(socket string) (*x509.Certificate, error) {
u, err := url.Parse(socket)
if err != nil {
return nil, err
}
host, _, err := net.SplitHostPort(u.Host)
if err != nil {
return nil, err
}
connRaw, err := net.Dial(u.Scheme, u.Host)
if err != nil {
return nil, err
}
err = connRaw.SetDeadline(time.Now().Add(5 * time.Second))
if err != nil {
return nil, err
}
switch u.Path {
case "", "/":
// do nothing
case "/xmpp":
err = xmppStartTLS(connRaw, host)
if err != nil {
return nil, err
}
case "/smtp":
err = smtpStartTLS(connRaw, host)
if err != nil {
return nil, err
}
default:
return nil, fmt.Errorf("Unknown negotiation path: %q", u.Path)
}
connTLS := tls.Client(connRaw, &tls.Config{InsecureSkipVerify: true})
defer connTLS.Close()
err = connTLS.Handshake()
if err != nil {
return nil, err
}
cstate := connTLS.ConnectionState()
opts := x509.VerifyOptions{
DNSName: host,
Intermediates: x509.NewCertPool(),
}
for _, cert := range cstate.PeerCertificates[1:] {
opts.Intermediates.AddCert(cert)
}
cert := cstate.PeerCertificates[0]
_, err = cert.Verify(opts)
return cert, err
}
func split(socket string) (net, addr string) {
ary := strings.SplitN(socket, ":", 2)
if len(ary) == 1 {
return "tcp", ary[0]
}
return ary[0], ary[1]
}
func main() {
for _, socket := range os.Args[1:] {
fmt.Fprintf(os.Stderr, "Getting %q... ", socket)
block := pem.Block{
Type: "CERTIFICATE",
Headers: map[string]string{"X-Socket": socket},
Bytes: nil,
}
cert, err := getcert(socket)
if cert != nil {
block.Bytes = cert.Raw
}
if err != nil {
block.Headers["X-Error"] = err.Error()
}
pem.Encode(os.Stdout, &block)
fmt.Fprintln(os.Stderr, "[done]")
}
}
|
