Add support for AssumeRoleWithWebIdentity (#6985)

docs/sts/web-identity.go

@@ -0,0 +1,178 @@
+// +build ignore
+
+/*
+ * Minio Cloud Storage, (C) 2018 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package main
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/base64"
+	"encoding/json"
+	"encoding/xml"
+	"flag"
+	"fmt"
+	"log"
+	"net/http"
+	"net/url"
+	"time"
+
+	"golang.org/x/oauth2"
+	googleOAuth2 "golang.org/x/oauth2/google"
+
+	"github.com/minio/minio/pkg/auth"
+)
+
+// AssumedRoleUser - The identifiers for the temporary security credentials that
+// the operation returns. Please also see https://docs.aws.amazon.com/goto/WebAPI/sts-2011-06-15/AssumedRoleUser
+type AssumedRoleUser struct {
+	Arn           string
+	AssumedRoleID string `xml:"AssumeRoleId"`
+	// contains filtered or unexported fields
+}
+
+// AssumeRoleWithWebIdentityResponse contains the result of successful AssumeRoleWithWebIdentity request.
+type AssumeRoleWithWebIdentityResponse struct {
+	XMLName          xml.Name          `xml:"https://sts.amazonaws.com/doc/2011-06-15/ AssumeRoleWithWebIdentityResponse" json:"-"`
+	Result           WebIdentityResult `xml:"AssumeRoleWithWebIdentityResult"`
+	ResponseMetadata struct {
+		RequestID string `xml:"RequestId,omitempty"`
+	} `xml:"ResponseMetadata,omitempty"`
+}
+
+// WebIdentityResult - Contains the response to a successful AssumeRoleWithWebIdentity
+// request, including temporary credentials that can be used to make Minio API requests.
+type WebIdentityResult struct {
+	AssumedRoleUser             AssumedRoleUser  `xml:",omitempty"`
+	Audience                    string           `xml:",omitempty"`
+	Credentials                 auth.Credentials `xml:",omitempty"`
+	PackedPolicySize            int              `xml:",omitempty"`
+	Provider                    string           `xml:",omitempty"`
+	SubjectFromWebIdentityToken string           `xml:",omitempty"`
+}
+
+// Returns a base64 encoded random 32 byte string.
+func randomState() string {
+	b := make([]byte, 32)
+	rand.Read(b)
+	return base64.RawURLEncoding.EncodeToString(b)
+}
+
+var (
+	stsEndpoint   string
+	authEndpoint  string
+	tokenEndpoint string
+	clientID      string
+	clientSecret  string
+)
+
+func init() {
+	flag.StringVar(&stsEndpoint, "sts-ep", "http://localhost:9000", "STS endpoint")
+	flag.StringVar(&authEndpoint, "auth-ep", googleOAuth2.Endpoint.AuthURL, "Auth endpoint")
+	flag.StringVar(&tokenEndpoint, "token-ep", googleOAuth2.Endpoint.TokenURL, "Token endpoint")
+	flag.StringVar(&clientID, "cid", "", "Client ID")
+	flag.StringVar(&clientSecret, "csec", "", "Client secret")
+}
+
+func main() {
+	flag.Parse()
+	if clientID == "" || clientSecret == "" {
+		flag.PrintDefaults()
+		return
+	}
+
+	ctx := context.Background()
+
+	config := oauth2.Config{
+		ClientID:     clientID,
+		ClientSecret: clientSecret,
+		Endpoint: oauth2.Endpoint{
+			AuthURL:  authEndpoint,
+			TokenURL: tokenEndpoint,
+		},
+		RedirectURL: "http://localhost:8080/oauth2/callback",
+		Scopes:      []string{"openid", "profile", "email"},
+	}
+
+	state := randomState()
+
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		http.Redirect(w, r, config.AuthCodeURL(state), http.StatusFound)
+	})
+
+	http.HandleFunc("/oauth2/callback", func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Query().Get("state") != state {
+			http.Error(w, "state did not match", http.StatusBadRequest)
+			return
+		}
+
+		oauth2Token, err := config.Exchange(ctx, r.URL.Query().Get("code"))
+		if err != nil {
+			http.Error(w, "Failed to exchange token: "+err.Error(), http.StatusInternalServerError)
+			return
+		}
+
+		if oauth2Token.Valid() {
+			v := url.Values{}
+			v.Set("Action", "AssumeRoleWithWebIdentity")
+			v.Set("WebIdentityToken", fmt.Sprintf("%s", oauth2Token.Extra("id_token")))
+			v.Set("DurationSeconds", fmt.Sprintf("%d", int64(oauth2Token.Expiry.Sub(time.Now().UTC()).Seconds())))
+			v.Set("Version", "2011-06-15")
+
+			u, err := url.Parse("http://localhost:9000")
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+			u.RawQuery = v.Encode()
+
+			req, err := http.NewRequest("POST", u.String(), nil)
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+			resp, err := http.DefaultClient.Do(req)
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+
+			}
+			defer resp.Body.Close()
+			if resp.StatusCode != http.StatusOK {
+				http.Error(w, resp.Status, resp.StatusCode)
+				return
+			}
+
+			a := AssumeRoleWithWebIdentityResponse{}
+			if err = xml.NewDecoder(resp.Body).Decode(&a); err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+
+			w.Write([]byte("##### Credentials\n"))
+			c, err := json.MarshalIndent(a.Result.Credentials, "", "\t")
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+			w.Write(c)
+		}
+	})
+
+	log.Printf("listening on http://%s/", "localhost:8080")
+	log.Fatal(http.ListenAndServe("localhost:8080", nil))
+}