583bcfb3c7
"Inspired" by https://github.com/BenLubar/Rnoadm/maybetls but avoids pulling the whole game as a dependency, and has the API slightly changed, as it makes no sense to have non-tcp TLS listeners.
124 lines
2.9 KiB
Go
124 lines
2.9 KiB
Go
// Copyright (C) 2014 Jakob Borg and Contributors (see the CONTRIBUTORS file).
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// All rights reserved. Use of this source code is governed by an MIT-style
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// license that can be found in the LICENSE file.
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package main
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import (
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"bytes"
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"crypto/rand"
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"crypto/rsa"
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"crypto/sha256"
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"crypto/tls"
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"crypto/x509"
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"crypto/x509/pkix"
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"encoding/binary"
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"encoding/pem"
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"io"
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"math/big"
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mr "math/rand"
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"net"
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"os"
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"path/filepath"
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"time"
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)
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const (
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tlsRSABits = 3072
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tlsName = "syncthing"
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)
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func loadCert(dir string, prefix string) (tls.Certificate, error) {
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cf := filepath.Join(dir, prefix+"cert.pem")
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kf := filepath.Join(dir, prefix+"key.pem")
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return tls.LoadX509KeyPair(cf, kf)
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}
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func certSeed(bs []byte) int64 {
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hf := sha256.New()
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hf.Write(bs)
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id := hf.Sum(nil)
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return int64(binary.BigEndian.Uint64(id))
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}
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func newCertificate(dir string, prefix string) {
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l.Infoln("Generating RSA key and certificate...")
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priv, err := rsa.GenerateKey(rand.Reader, tlsRSABits)
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l.FatalErr(err)
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notBefore := time.Now()
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notAfter := time.Date(2049, 12, 31, 23, 59, 59, 0, time.UTC)
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template := x509.Certificate{
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SerialNumber: new(big.Int).SetInt64(mr.Int63()),
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Subject: pkix.Name{
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CommonName: tlsName,
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},
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NotBefore: notBefore,
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NotAfter: notAfter,
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KeyUsage: x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
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ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth, x509.ExtKeyUsageClientAuth},
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BasicConstraintsValid: true,
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}
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derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, &priv.PublicKey, priv)
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l.FatalErr(err)
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certOut, err := os.Create(filepath.Join(dir, prefix+"cert.pem"))
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l.FatalErr(err)
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pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes})
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certOut.Close()
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keyOut, err := os.OpenFile(filepath.Join(dir, prefix+"key.pem"), os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
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l.FatalErr(err)
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pem.Encode(keyOut, &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(priv)})
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keyOut.Close()
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}
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type DowngradingListener struct {
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net.Listener
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TLSConfig *tls.Config
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}
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type WrappedConnection struct {
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io.Reader
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net.Conn
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}
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func NewDowngradingListener(address string, config *tls.Config) (net.Listener, error) {
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listener, err := net.Listen("tcp", address)
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if err != nil {
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return nil, err
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}
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return &DowngradingListener{listener, config}, nil
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}
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func (listener *DowngradingListener) Accept() (net.Conn, error) {
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connection, err := listener.Listener.Accept()
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if err != nil {
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return nil, err
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}
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var peek [1]byte
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_, err = io.ReadFull(connection, peek[:])
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if err != nil {
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return nil, err
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}
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jointReader := io.MultiReader(bytes.NewReader(peek[:]), connection)
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wrapper := &WrappedConnection{jointReader, connection}
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// TLS handshake starts with ASCII SYN
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if peek[0] == 22 {
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return tls.Server(wrapper, listener.TLSConfig), nil
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}
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return wrapper, nil
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}
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func (c *WrappedConnection) Read(b []byte) (n int, err error) {
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return c.Reader.Read(b)
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}
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