blob: 263eed828c40a21eb9db1554f63ed9ef016d70c4 [file] [log] [blame]
// Copyright 2019 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.
// authtest is a diagnostic tool for implementations of the GOAUTH protocol
// described in https://golang.org/issue/26232.
//
// It accepts a single URL as an argument, and executes the GOAUTH protocol to
// fetch and display the headers for that URL.
//
// CAUTION: authtest logs the GOAUTH responses, which may include user
// credentials, to stderr. Do not post its output unless you are certain that
// all of the credentials involved are fake!
package main
import (
"bufio"
"bytes"
"flag"
"fmt"
"io"
"log"
"net/http"
"net/textproto"
"net/url"
"os"
"os/exec"
"path/filepath"
"strings"
)
var v = flag.Bool("v", false, "if true, log GOAUTH responses to stderr")
func main() {
log.SetFlags(log.LstdFlags | log.Lshortfile)
flag.Parse()
args := flag.Args()
if len(args) != 1 {
log.Fatalf("usage: [GOAUTH=CMD...] %s URL", filepath.Base(os.Args[0]))
}
resp := try(args[0], nil)
if resp.StatusCode == http.StatusOK {
return
}
resp = try(args[0], resp)
if resp.StatusCode != http.StatusOK {
os.Exit(1)
}
}
func try(url string, prev *http.Response) *http.Response {
req := new(http.Request)
if prev != nil {
*req = *prev.Request
} else {
var err error
req, err = http.NewRequest("HEAD", os.Args[1], nil)
if err != nil {
log.Fatal(err)
}
}
goauth:
for _, argList := range strings.Split(os.Getenv("GOAUTH"), ";") {
// TODO(golang.org/issue/26849): If we escape quoted strings in GOFLAGS, use
// the same quoting here.
args := strings.Split(argList, " ")
if len(args) == 0 || args[0] == "" {
log.Fatalf("invalid or empty command in GOAUTH")
}
creds, err := getCreds(args, prev)
if err != nil {
log.Fatal(err)
}
for _, c := range creds {
if c.Apply(req) {
fmt.Fprintf(os.Stderr, "# request to %s\n", req.URL)
fmt.Fprintf(os.Stderr, "%s %s %s\n", req.Method, req.URL, req.Proto)
req.Header.Write(os.Stderr)
fmt.Fprintln(os.Stderr)
break goauth
}
}
}
resp, err := http.DefaultClient.Do(req)
if err != nil {
log.Fatal(err)
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusOK && resp.StatusCode < 400 || resp.StatusCode > 500 {
log.Fatalf("unexpected status: %v", resp.Status)
}
fmt.Fprintf(os.Stderr, "# response from %s\n", resp.Request.URL)
formatHead(os.Stderr, resp)
return resp
}
func formatHead(out io.Writer, resp *http.Response) {
fmt.Fprintf(out, "%s %s\n", resp.Proto, resp.Status)
if err := resp.Header.Write(out); err != nil {
log.Fatal(err)
}
fmt.Fprintln(out)
}
type Cred struct {
URLPrefixes []*url.URL
Header http.Header
}
func (c Cred) Apply(req *http.Request) bool {
if req.URL == nil {
return false
}
ok := false
for _, prefix := range c.URLPrefixes {
if prefix.Host == req.URL.Host &&
(req.URL.Path == prefix.Path ||
(strings.HasPrefix(req.URL.Path, prefix.Path) &&
(strings.HasSuffix(prefix.Path, "/") ||
req.URL.Path[len(prefix.Path)] == '/'))) {
ok = true
break
}
}
if !ok {
return false
}
for k, vs := range c.Header {
req.Header.Del(k)
for _, v := range vs {
req.Header.Add(k, v)
}
}
return true
}
func (c Cred) String() string {
var buf strings.Builder
for _, u := range c.URLPrefixes {
fmt.Fprintln(&buf, u)
}
buf.WriteString("\n")
c.Header.Write(&buf)
buf.WriteString("\n")
return buf.String()
}
func getCreds(args []string, resp *http.Response) ([]Cred, error) {
cmd := exec.Command(args[0], args[1:]...)
cmd.Stderr = os.Stderr
if resp != nil {
u := *resp.Request.URL
u.RawQuery = ""
cmd.Args = append(cmd.Args, u.String())
}
var head strings.Builder
if resp != nil {
formatHead(&head, resp)
}
cmd.Stdin = strings.NewReader(head.String())
fmt.Fprintf(os.Stderr, "# %s\n", strings.Join(cmd.Args, " "))
out, err := cmd.Output()
if err != nil {
return nil, fmt.Errorf("%s: %v", strings.Join(cmd.Args, " "), err)
}
os.Stderr.Write(out)
os.Stderr.WriteString("\n")
var creds []Cred
r := textproto.NewReader(bufio.NewReader(bytes.NewReader(out)))
line := 0
readLoop:
for {
var prefixes []*url.URL
for {
prefix, err := r.ReadLine()
if err == io.EOF {
if len(prefixes) > 0 {
return nil, fmt.Errorf("line %d: %v", line, io.ErrUnexpectedEOF)
}
break readLoop
}
line++
if prefix == "" {
if len(prefixes) == 0 {
return nil, fmt.Errorf("line %d: unexpected newline", line)
}
break
}
u, err := url.Parse(prefix)
if err != nil {
return nil, fmt.Errorf("line %d: malformed URL: %v", line, err)
}
if u.Scheme != "https" {
return nil, fmt.Errorf("line %d: non-HTTPS URL %q", line, prefix)
}
if len(u.RawQuery) > 0 {
return nil, fmt.Errorf("line %d: unexpected query string in URL %q", line, prefix)
}
if len(u.Fragment) > 0 {
return nil, fmt.Errorf("line %d: unexpected fragment in URL %q", line, prefix)
}
prefixes = append(prefixes, u)
}
header, err := r.ReadMIMEHeader()
if err != nil {
return nil, fmt.Errorf("headers at line %d: %v", line, err)
}
if len(header) > 0 {
creds = append(creds, Cred{
URLPrefixes: prefixes,
Header: http.Header(header),
})
}
}
return creds, nil
}