go-mockid/mockid/mockid.go

461 lines
12 KiB
Go

package mockid
import (
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rand"
"crypto/sha256"
"crypto/sha512"
"encoding/base64"
"encoding/json"
"fmt"
"io/ioutil"
"log"
"math/big"
"net/http"
"net/url"
"path/filepath"
"strconv"
"strings"
"time"
)
type PrivateJWK struct {
PublicJWK
D string `json:"d"`
}
type PublicJWK struct {
Crv string `json:"crv"`
KeyID string `json:"kid,omitempty"`
Kty string `json:"kty,omitempty"`
X string `json:"x"`
Y string `json:"y"`
}
var nonces map[string]int64
func init() {
nonces = make(map[string]int64)
}
func Route(jwksPrefix string, priv *ecdsa.PrivateKey, jwk *PrivateJWK) {
pub := &priv.PublicKey
thumbprint := thumbprintKey(pub)
http.HandleFunc("/api/new-nonce", func(w http.ResponseWriter, r *http.Request) {
baseURL := getBaseURL(r)
/*
res.statusCode = 200;
res.setHeader("Cache-Control", "max-age=0, no-cache, no-store");
// TODO
//res.setHeader("Date", "Sun, 10 Mar 2019 08:04:45 GMT");
// is this the expiration of the nonce itself? methinks maybe so
//res.setHeader("Expires", "Sun, 10 Mar 2019 08:04:45 GMT");
// TODO use one of the registered domains
//var indexUrl = "https://acme-staging-v02.api.letsencrypt.org/index"
*/
//var port = (state.config.ipc && state.config.ipc.port || state._ipc.port || undefined);
//var indexUrl = "http://localhost:" + port + "/index";
indexUrl := baseURL + "/index"
w.Header().Set("Link", "<"+indexUrl+">;rel=\"index\"")
w.Header().Set("Cache-Control", "max-age=0, no-cache, no-store")
w.Header().Set("Pragma", "no-cache")
//res.setHeader("Strict-Transport-Security", "max-age=604800");
w.Header().Set("X-Frame-Options", "DENY")
issueNonce(w, r)
})
http.HandleFunc("/api/new-account", requireNonce(func(w http.ResponseWriter, r *http.Request) {
http.Error(w, "Not Implemented", http.StatusNotImplemented)
}))
http.HandleFunc("/api/jwks", func(w http.ResponseWriter, r *http.Request) {
log.Printf("%s %s %s", r.Method, r.Host, r.URL.Path)
if "POST" != r.Method {
http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
return
}
tok := make(map[string]interface{})
decoder := json.NewDecoder(r.Body)
err := decoder.Decode(&tok)
if nil != err {
http.Error(w, "Bad Request: invalid json", http.StatusBadRequest)
return
}
defer r.Body.Close()
// TODO better, JSON error messages
if _, ok := tok["d"]; ok {
http.Error(w, "Bad Request: private key", http.StatusBadRequest)
return
}
kty, _ := tok["kty"].(string)
switch kty {
case "EC":
postEC(jwksPrefix, tok, w, r)
case "RSA":
postRSA(jwksPrefix, tok, w, r)
default:
http.Error(w, "Bad Request: only EC and RSA keys are supported", http.StatusBadRequest)
return
}
})
http.HandleFunc("/access_token", func(w http.ResponseWriter, r *http.Request) {
log.Printf("%s %s\n", r.Method, r.URL.Path)
_, _, token := GenToken(getBaseURL(r), priv, r.URL.Query())
fmt.Fprintf(w, token)
})
http.HandleFunc("/authorization_header", func(w http.ResponseWriter, r *http.Request) {
log.Printf("%s %s\n", r.Method, r.URL.Path)
var header string
headers, _ := r.URL.Query()["header"]
if 0 == len(headers) {
header = "Authorization"
} else {
header = headers[0]
}
var prefix string
prefixes, _ := r.URL.Query()["prefix"]
if 0 == len(prefixes) {
prefix = "Bearer "
} else {
prefix = prefixes[0]
}
_, _, token := GenToken(getBaseURL(r), priv, r.URL.Query())
fmt.Fprintf(w, "%s: %s%s", header, prefix, token)
})
http.HandleFunc("/key.jwk.json", func(w http.ResponseWriter, r *http.Request) {
log.Printf("%s %s", r.Method, r.URL.Path)
fmt.Fprintf(w, `{ "kty": "EC" , "crv": %q , "d": %q , "x": %q , "y": %q , "ext": true , "key_ops": ["sign"] }`, jwk.Crv, jwk.D, jwk.X, jwk.Y)
})
http.HandleFunc("/.well-known/openid-configuration", func(w http.ResponseWriter, r *http.Request) {
baseURL := getBaseURL(r)
log.Printf("%s %s\n", r.Method, r.URL.Path)
fmt.Fprintf(w, `{ "issuer": "%s", "jwks_uri": "%s/.well-known/jwks.json" }`, baseURL, baseURL)
})
http.HandleFunc("/.well-known/jwks.json", func(w http.ResponseWriter, r *http.Request) {
log.Printf("%s %s %s", r.Method, r.Host, r.URL.Path)
parts := strings.Split(r.Host, ".")
kid := parts[0]
b, err := ioutil.ReadFile(filepath.Join(jwksPrefix, strings.ToLower(kid)+".jwk.json"))
if nil != err {
//http.Error(w, "Not Found", http.StatusNotFound)
jwkstr := fmt.Sprintf(
`{ "keys": [ { "kty": "EC" , "crv": %q , "x": %q , "y": %q , "kid": %q , "ext": true , "key_ops": ["verify"] , "exp": %s } ] }`,
jwk.Crv, jwk.X, jwk.Y, thumbprint, strconv.FormatInt(time.Now().Add(15*time.Minute).Unix(), 10),
)
fmt.Println(jwkstr)
fmt.Fprintf(w, jwkstr)
return
}
tok := &PublicJWK{}
err = json.Unmarshal(b, tok)
if nil != err {
// TODO delete the bad file?
http.Error(w, "Internal Server Error", http.StatusInternalServerError)
return
}
jwkstr := fmt.Sprintf(
`{ "keys": [ { "kty": "EC", "crv": %q, "x": %q, "y": %q, "kid": %q,`+
` "ext": true, "key_ops": ["verify"], "exp": %s } ] }`,
tok.Crv, tok.X, tok.Y, tok.KeyID, strconv.FormatInt(time.Now().Add(15*time.Minute).Unix(), 10),
)
fmt.Println(jwkstr)
fmt.Fprintf(w, jwkstr)
})
}
func parseExp(exp string) (int, error) {
if "" == exp {
exp = "15m"
}
mult := 1
switch exp[len(exp)-1] {
case 'w':
mult *= 7
fallthrough
case 'd':
mult *= 24
fallthrough
case 'h':
mult *= 60
fallthrough
case 'm':
mult *= 60
fallthrough
case 's':
// no fallthrough
default:
// could be 'k' or 'z', but we assume its empty
exp += "s"
}
num, err := strconv.Atoi(exp[:len(exp)-1])
if nil != err {
return 0, err
}
return num * mult, nil
}
func postEC(jwksPrefix string, tok map[string]interface{}, w http.ResponseWriter, r *http.Request) {
crv, ok := tok["crv"].(string)
if 5 != len(crv) || "P-" != crv[:2] {
http.Error(w, "Bad Request: bad curve", http.StatusBadRequest)
return
}
x, ok := tok["x"].(string)
if !ok {
http.Error(w, "Bad Request: missing 'x'", http.StatusBadRequest)
return
}
y, ok := tok["y"].(string)
if !ok {
http.Error(w, "Bad Request: missing 'y'", http.StatusBadRequest)
return
}
thumbprintable := []byte(
fmt.Sprintf(`{"crv":%q,"kty":"EC","x":%q,"y":%q}`, crv, x, y),
)
alg := crv[2:]
var thumb []byte
switch alg {
case "256":
hash := sha256.Sum256(thumbprintable)
thumb = hash[:]
case "384":
hash := sha512.Sum384(thumbprintable)
thumb = hash[:]
case "521":
fallthrough
case "512":
hash := sha512.Sum512(thumbprintable)
thumb = hash[:]
default:
http.Error(w, "Bad Request: bad key length or curve", http.StatusBadRequest)
return
}
kid := base64.RawURLEncoding.EncodeToString(thumb)
if kid2, _ := tok["kid"].(string); "" != kid2 && kid != kid2 {
http.Error(w, "Bad Request: kid should be "+kid, http.StatusBadRequest)
return
}
pub := []byte(fmt.Sprintf(
`{"crv":%q,"kid":%q,"kty":"EC","x":%q,"y":%q}`, crv, kid, x, y,
))
// TODO allow posting at the top-level?
// TODO support a group of keys by PPID
// (right now it's only by KID)
if !strings.HasPrefix(r.Host, strings.ToLower(kid)+".") {
http.Error(w, "Bad Request: prefix should be "+kid, http.StatusBadRequest)
return
}
if err := ioutil.WriteFile(
filepath.Join(jwksPrefix, strings.ToLower(kid)+".jwk.json"),
pub,
0644,
); nil != err {
fmt.Println("can't write file")
http.Error(w, "Internal Server Error", http.StatusInternalServerError)
return
}
baseURL := getBaseURL(r)
w.Write([]byte(fmt.Sprintf(
`{ "iss":%q, "jwks_url":%q }`, baseURL+"/", baseURL+"/.well-known/jwks.json",
)))
}
func postRSA(jwksPrefix string, tok map[string]interface{}, w http.ResponseWriter, r *http.Request) {
e, ok := tok["e"].(string)
if !ok {
http.Error(w, "Bad Request: missing 'e'", http.StatusBadRequest)
return
}
n, ok := tok["n"].(string)
if !ok {
http.Error(w, "Bad Request: missing 'n'", http.StatusBadRequest)
return
}
thumbprintable := []byte(
fmt.Sprintf(`{"e":%q,"kty":"RSA","n":%q}`, e, n),
)
var thumb []byte
// TODO handle bit lengths well
switch 3 * (len(n) / 4.0) {
case 256:
hash := sha256.Sum256(thumbprintable)
thumb = hash[:]
case 384:
hash := sha512.Sum384(thumbprintable)
thumb = hash[:]
case 512:
hash := sha512.Sum512(thumbprintable)
thumb = hash[:]
default:
http.Error(w, "Bad Request: only standard RSA key lengths (2048, 3072, 4096) are supported", http.StatusBadRequest)
return
}
kid := base64.RawURLEncoding.EncodeToString(thumb)
if kid2, _ := tok["kid"].(string); "" != kid2 && kid != kid2 {
http.Error(w, "Bad Request: kid should be "+kid, http.StatusBadRequest)
return
}
pub := []byte(fmt.Sprintf(
`{"e":%q,"kid":%q,"kty":"EC","n":%q}`, e, kid, n,
))
// TODO allow posting at the top-level?
// TODO support a group of keys by PPID
// (right now it's only by KID)
if !strings.HasPrefix(r.Host, strings.ToLower(kid)+".") {
http.Error(w, "Bad Request: prefix should be "+kid, http.StatusBadRequest)
return
}
if err := ioutil.WriteFile(
filepath.Join(jwksPrefix, strings.ToLower(kid)+".jwk.json"),
pub,
0644,
); nil != err {
fmt.Println("can't write file")
http.Error(w, "Internal Server Error", http.StatusInternalServerError)
return
}
baseURL := getBaseURL(r)
w.Write([]byte(fmt.Sprintf(
`{ "iss":%q, "jwks_url":%q }`, baseURL+"/", baseURL+"/.well-known/jwks.json",
)))
}
func GenToken(host string, priv *ecdsa.PrivateKey, query url.Values) (string, string, string) {
thumbprint := thumbprintKey(&priv.PublicKey)
protected := fmt.Sprintf(`{"typ":"JWT","alg":"ES256","kid":"%s"}`, thumbprint)
protected64 := base64.RawURLEncoding.EncodeToString([]byte(protected))
exp, err := parseExp(query.Get("exp"))
if nil != err {
// cryptic error code
// TODO propagate error
exp = 422
}
payload := fmt.Sprintf(
`{"iss":"%s/","sub":"dummy","exp":%s}`,
host, strconv.FormatInt(time.Now().Add(time.Duration(exp)*time.Second).Unix(), 10),
)
payload64 := base64.RawURLEncoding.EncodeToString([]byte(payload))
hash := sha256.Sum256([]byte(fmt.Sprintf(`%s.%s`, protected64, payload64)))
r, s, _ := ecdsa.Sign(rand.Reader, priv, hash[:])
rb := r.Bytes()
for len(rb) < 32 {
rb = append([]byte{0}, rb...)
}
sb := s.Bytes()
for len(rb) < 32 {
sb = append([]byte{0}, sb...)
}
sig64 := base64.RawURLEncoding.EncodeToString(append(rb, sb...))
token := fmt.Sprintf(`%s.%s.%s`, protected64, payload64, sig64)
return protected, payload, token
}
func ParseKey(jwk *PrivateJWK) *ecdsa.PrivateKey {
xb, _ := base64.RawURLEncoding.DecodeString(jwk.X)
xi := &big.Int{}
xi.SetBytes(xb)
yb, _ := base64.RawURLEncoding.DecodeString(jwk.Y)
yi := &big.Int{}
yi.SetBytes(yb)
pub := &ecdsa.PublicKey{
Curve: elliptic.P256(),
X: xi,
Y: yi,
}
db, _ := base64.RawURLEncoding.DecodeString(jwk.D)
di := &big.Int{}
di.SetBytes(db)
priv := &ecdsa.PrivateKey{
PublicKey: *pub,
D: di,
}
return priv
}
func thumbprintKey(pub *ecdsa.PublicKey) string {
minpub := []byte(fmt.Sprintf(`{"crv":%q,"kty":"EC","x":%q,"y":%q}`, "P-256", pub.X, pub.Y))
sha := sha256.Sum256(minpub)
return base64.RawURLEncoding.EncodeToString(sha[:])
}
func issueNonce(w http.ResponseWriter, r *http.Request) {
b := make([]byte, 16)
_, _ = rand.Read(b)
nonce := base64.RawURLEncoding.EncodeToString(b)
nonces[nonce] = time.Now().Unix()
w.Header().Set("Replay-Nonce", nonce)
}
func requireNonce(next http.HandlerFunc) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
nonce := r.Header.Get("Replay-Nonce")
// TODO expire nonces every so often
t := nonces[nonce]
if 0 == t {
http.Error(
w,
`{ "error": "invalid or expired nonce", "error_code": "ENONCE" }`,
http.StatusBadRequest,
)
return
}
delete(nonces, nonce)
issueNonce(w, r)
next(w, r)
}
}
func getBaseURL(r *http.Request) string {
var scheme string
if nil != r.TLS || "https" == r.Header.Get("X-Forwarded-Proto") {
scheme = "https:"
} else {
scheme = "http:"
}
return fmt.Sprintf(
"%s//%s",
scheme,
r.Host,
)
}