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|
package scepserver
import (
"bytes"
"context"
"encoding/base64"
"fmt"
"io"
"io/ioutil"
"net/http"
"net/url"
kitlog "github.com/go-kit/kit/log"
kithttp "github.com/go-kit/kit/transport/http"
"github.com/gorilla/mux"
"github.com/pkg/errors"
)
func MakeHTTPHandler(e *Endpoints, svc Service, logger kitlog.Logger) http.Handler {
opts := []kithttp.ServerOption{
kithttp.ServerErrorLogger(logger),
}
r := mux.NewRouter()
r.Methods("GET").Path("/scep").Handler(kithttp.NewServer(
e.GetEndpoint,
decodeSCEPRequest,
encodeSCEPResponse,
opts...,
))
r.Methods("POST").Path("/scep").Handler(kithttp.NewServer(
e.PostEndpoint,
decodeSCEPRequest,
encodeSCEPResponse,
opts...,
))
return r
}
// EncodeSCEPRequest encodes a SCEP HTTP Request. Used by the client.
func EncodeSCEPRequest(ctx context.Context, r *http.Request, request interface{}) error {
req := request.(SCEPRequest)
params := r.URL.Query()
params.Set("operation", req.Operation)
switch r.Method {
case "GET":
if len(req.Message) > 0 {
var msg string
if req.Operation == "PKIOperation" {
msg = base64.URLEncoding.EncodeToString(req.Message)
} else {
msg = string(req.Message)
}
params.Set("message", msg)
}
r.URL.RawQuery = params.Encode()
return nil
case "POST":
body := bytes.NewReader(req.Message)
// recreate the request here because IIS does not support chunked encoding by default
// and Go doesn't appear to set Content-Length if we use an io.ReadCloser
u := r.URL
u.RawQuery = params.Encode()
rr, err := http.NewRequest("POST", u.String(), body)
rr.Header.Set("Content-Type", "application/octet-stream")
if err != nil {
return errors.Wrapf(err, "creating new POST request for %s", req.Operation)
}
*r = *rr
return nil
default:
return fmt.Errorf("scep: %s method not supported", r.Method)
}
}
const maxPayloadSize = 2 << 20
func decodeSCEPRequest(ctx context.Context, r *http.Request) (interface{}, error) {
msg, err := message(r)
if err != nil {
return nil, err
}
defer r.Body.Close()
request := SCEPRequest{
Message: msg,
Operation: r.URL.Query().Get("operation"),
}
return request, nil
}
// extract message from request
func message(r *http.Request) ([]byte, error) {
switch r.Method {
case "GET":
var msg string
q := r.URL.Query()
if _, ok := q["message"]; ok {
msg = q.Get("message")
}
op := q.Get("operation")
if op == "PKIOperation" {
msg2, err := url.PathUnescape(msg)
if err != nil {
return nil, err
}
return base64.StdEncoding.DecodeString(msg2)
}
return []byte(msg), nil
case "POST":
return ioutil.ReadAll(io.LimitReader(r.Body, maxPayloadSize))
default:
return nil, errors.New("method not supported")
}
}
// EncodeSCEPResponse writes a SCEP response back to the SCEP client.
func encodeSCEPResponse(ctx context.Context, w http.ResponseWriter, response interface{}) error {
resp := response.(SCEPResponse)
if resp.Err != nil {
http.Error(w, resp.Err.Error(), http.StatusInternalServerError)
return nil
}
w.Header().Set("Content-Type", contentHeader(resp.operation, resp.CACertNum))
w.Write(resp.Data)
return nil
}
// DecodeSCEPResponse decodes a SCEP response
func DecodeSCEPResponse(ctx context.Context, r *http.Response) (interface{}, error) {
if r.StatusCode != http.StatusOK && r.StatusCode >= 400 {
body, _ := ioutil.ReadAll(io.LimitReader(r.Body, 4096))
return nil, fmt.Errorf("http request failed with status %s, msg: %s",
r.Status,
string(body),
)
}
data, err := ioutil.ReadAll(io.LimitReader(r.Body, maxPayloadSize))
if err != nil {
return nil, err
}
defer r.Body.Close()
resp := SCEPResponse{
Data: data,
}
header := r.Header.Get("Content-Type")
if header == certChainHeader {
// we only set it to two to indicate a cert chain.
// the actual number of certs will be in the payload.
resp.CACertNum = 2
}
return resp, nil
}
const (
certChainHeader = "application/x-x509-ca-ra-cert"
leafHeader = "application/x-x509-ca-cert"
pkiOpHeader = "application/x-pki-message"
)
func contentHeader(op string, certNum int) string {
switch op {
case "GetCACert":
if certNum > 1 {
return certChainHeader
}
return leafHeader
case "PKIOperation":
return pkiOpHeader
default:
return "text/plain"
}
}
|
