lego/acme/http_challenge.go
2015-11-12 22:49:02 +01:00

143 lines
3.4 KiB
Go

package acme
import (
"crypto"
"encoding/base64"
"encoding/json"
"errors"
"fmt"
"net"
"net/http"
"strings"
"time"
)
type httpChallenge struct {
jws *jws
optPort string
start chan net.Listener
end chan error
}
func (s *httpChallenge) Solve(chlng challenge, domain string) error {
logf("[INFO] acme: Trying to solve HTTP-01")
s.start = make(chan net.Listener)
s.end = make(chan error)
// Generate the Key Authorization for the challenge
key := keyAsJWK(&s.jws.privKey.PublicKey)
thumbBytes, err := key.Thumbprint(crypto.SHA256)
if err != nil {
return err
}
keyThumb := base64.URLEncoding.EncodeToString(thumbBytes)
index := strings.Index(keyThumb, "=")
if index != -1 {
keyThumb = keyThumb[:index]
}
keyAuth := chlng.Token + "." + keyThumb
go s.startHTTPServer(domain, chlng.Token, keyAuth)
var listener net.Listener
select {
case listener = <-s.start:
break
case err := <-s.end:
return fmt.Errorf("Could not start HTTP server for challenge -> %v", err)
}
// Make sure we properly close the HTTP server before we return
defer func() {
listener.Close()
err = <-s.end
close(s.start)
close(s.end)
}()
jsonBytes, err := json.Marshal(challenge{Resource: "challenge", Type: chlng.Type, Token: chlng.Token, KeyAuthorization: keyAuth})
if err != nil {
return errors.New("Failed to marshal network message...")
}
// Tell the server we handle HTTP-01
resp, err := s.jws.post(chlng.URI, jsonBytes)
if err != nil {
return fmt.Errorf("Failed to post JWS message. -> %v", err)
}
// After the path is sent, the ACME server will access our server.
// Repeatedly check the server for an updated status on our request.
var challengeResponse challenge
Loop:
for {
if resp.StatusCode >= http.StatusBadRequest {
return handleHTTPError(resp)
}
err = json.NewDecoder(resp.Body).Decode(&challengeResponse)
resp.Body.Close()
if err != nil {
return err
}
switch challengeResponse.Status {
case "valid":
logf("The server validated our request")
break Loop
case "pending":
break
case "invalid":
return errors.New("The server could not validate our request.")
default:
return errors.New("The server returned an unexpected state.")
}
time.Sleep(1 * time.Second)
resp, err = http.Get(chlng.URI)
}
return nil
}
func (s *httpChallenge) startHTTPServer(domain string, token string, keyAuth string) {
// Allow for CLI port override
port := ":80"
if s.optPort != "" {
port = ":" + s.optPort
}
listener, err := net.Listen("tcp", domain+port)
if err != nil {
// if the domain:port bind failed, fall back to :port bind and try that instead.
listener, err = net.Listen("tcp", port)
if err != nil {
s.end <- err
}
}
// Signal successfull start
s.start <- listener
path := "/.well-known/acme-challenge/" + token
// The handler validates the HOST header and request type.
// For validation it then writes the token the server returned with the challenge
http.HandleFunc(path, func(w http.ResponseWriter, r *http.Request) {
if strings.HasPrefix(r.Host, domain) && r.Method == "GET" {
w.Header().Add("Content-Type", "text/plain")
w.Write([]byte(keyAuth))
logf("Served Key Authentication ...")
} else {
logf("Received request for domain %s with method %s", r.Host, r.Method)
w.Write([]byte("TEST"))
}
})
http.Serve(listener, nil)
// Signal that the server was shut down
s.end <- nil
}