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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tls
import (
"bufio"
"encoding/hex"
"errors"
"flag"
"fmt"
"io"
"io/ioutil"
"net"
"strconv"
"strings"
"sync"
)
// TLS reference tests run a connection against a reference implementation
// (OpenSSL) of TLS and record the bytes of the resulting connection. The Go
// code, during a test, is configured with deterministic randomness and so the
// reference test can be reproduced exactly in the future.
//
// In order to save everyone who wishes to run the tests from needing the
// reference implementation installed, the reference connections are saved in
// files in the testdata directory. Thus running the tests involves nothing
// external, but creating and updating them requires the reference
// implementation.
//
// Tests can be updated by running them with the -update flag. This will cause
// the test files. Generally one should combine the -update flag with -test.run
// to updated a specific test. Since the reference implementation will always
// generate fresh random numbers, large parts of the reference connection will
// always change.
var update = flag.Bool("update", false, "update golden files on disk")
// recordingConn is a net.Conn that records the traffic that passes through it.
// WriteTo can be used to produce output that can be later be loaded with
// ParseTestData.
type recordingConn struct {
net.Conn
sync.Mutex
flows [][]byte
reading bool
}
func (r *recordingConn) Read(b []byte) (n int, err error) {
if n, err = r.Conn.Read(b); n == 0 {
return
}
b = b[:n]
r.Lock()
defer r.Unlock()
if l := len(r.flows); l == 0 || !r.reading {
buf := make([]byte, len(b))
copy(buf, b)
r.flows = append(r.flows, buf)
} else {
r.flows[l-1] = append(r.flows[l-1], b[:n]...)
}
r.reading = true
return
}
func (r *recordingConn) Write(b []byte) (n int, err error) {
if n, err = r.Conn.Write(b); n == 0 {
return
}
b = b[:n]
r.Lock()
defer r.Unlock()
if l := len(r.flows); l == 0 || r.reading {
buf := make([]byte, len(b))
copy(buf, b)
r.flows = append(r.flows, buf)
} else {
r.flows[l-1] = append(r.flows[l-1], b[:n]...)
}
r.reading = false
return
}
// WriteTo writes Go source code to w that contains the recorded traffic.
func (r *recordingConn) WriteTo(w io.Writer) {
// TLS always starts with a client to server flow.
clientToServer := true
for i, flow := range r.flows {
source, dest := "client", "server"
if !clientToServer {
source, dest = dest, source
}
fmt.Fprintf(w, ">>> Flow %d (%s to %s)\n", i+1, source, dest)
dumper := hex.Dumper(w)
dumper.Write(flow)
dumper.Close()
clientToServer = !clientToServer
}
}
func parseTestData(r io.Reader) (flows [][]byte, err error) {
var currentFlow []byte
scanner := bufio.NewScanner(r)
for scanner.Scan() {
line := scanner.Text()
// If the line starts with ">>> " then it marks the beginning
// of a new flow.
if strings.HasPrefix(line, ">>> ") {
if len(currentFlow) > 0 || len(flows) > 0 {
flows = append(flows, currentFlow)
currentFlow = nil
}
continue
}
// Otherwise the line is a line of hex dump that looks like:
// 00000170 fc f5 06 bf (...) |.....X{&?......!|
// (Some bytes have been omitted from the middle section.)
if i := strings.IndexByte(line, ' '); i >= 0 {
line = line[i:]
} else {
return nil, errors.New("invalid test data")
}
if i := strings.IndexByte(line, '|'); i >= 0 {
line = line[:i]
} else {
return nil, errors.New("invalid test data")
}
hexBytes := strings.Fields(line)
for _, hexByte := range hexBytes {
val, err := strconv.ParseUint(hexByte, 16, 8)
if err != nil {
return nil, errors.New("invalid hex byte in test data: " + err.Error())
}
currentFlow = append(currentFlow, byte(val))
}
}
if len(currentFlow) > 0 {
flows = append(flows, currentFlow)
}
return flows, nil
}
// tempFile creates a temp file containing contents and returns its path.
func tempFile(contents string) string {
file, err := ioutil.TempFile("", "go-tls-test")
if err != nil {
panic("failed to create temp file: " + err.Error())
}
path := file.Name()
file.WriteString(contents)
file.Close()
return path
}
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