FEATURE: add JWT to HTTP endpoints of Filer and use them in S3 Client

- one JWT for reading and one for writing, analogous to how the JWT
  between Master and Volume Server works
- I did not implement IP `whiteList` parameter on the filer

Additionally, because http_util.DownloadFile now sets the JWT,
the `download` command should now work when `jwt.signing.read` is
configured. By looking at the code, I think this case did not work
before.

## Docs to be adjusted after a release

Page `Amazon-S3-API`:

```
# Authentication with Filer

You can use mTLS for the gRPC connection between S3-API-Proxy and the filer, as
explained in [Security-Configuration](Security-Configuration) -
controlled by the `grpc.*` configuration in `security.toml`.

Starting with version XX, it is also possible to authenticate the HTTP
operations between the S3-API-Proxy and the Filer (especially
uploading new files). This is configured by setting
`filer_jwt.signing.key` and `filer_jwt.signing.read.key` in
`security.toml`.

With both configurations (gRPC and JWT), it is possible to have Filer
and S3 communicate in fully authenticated fashion; so Filer will reject
any unauthenticated communication.
```

Page `Security Overview`:

```
The following items are not covered, yet:

- master server http REST services

Starting with version XX, the Filer HTTP REST services can be secured
with a JWT, by setting `filer_jwt.signing.key` and
`filer_jwt.signing.read.key` in `security.toml`.

...

Before version XX: "weed filer -disableHttp", disable http operations, only gRPC operations are allowed. This works with "weed mount" by FUSE. It does **not work** with the [S3 Gateway](Amazon S3 API), as this does HTTP calls to the Filer.
Starting with version XX: secured by JWT, by setting `filer_jwt.signing.key` and `filer_jwt.signing.read.key` in `security.toml`. **This now works with the [S3 Gateway](Amazon S3 API).**

...

# Securing Filer HTTP with JWT

To enable JWT-based access control for the Filer,

1. generate `security.toml` file by `weed scaffold -config=security`
2. set `filer_jwt.signing.key` to a secret string - and optionally filer_jwt.signing.read.key` as well to a secret string
3. copy the same `security.toml` file to the filers and all S3 proxies.

If `filer_jwt.signing.key` is configured: When sending upload/update/delete HTTP operations to a filer server, the request header `Authorization` should be the JWT string (`Authorization: Bearer [JwtToken]`). The operation is authorized after the filer validates the JWT with `filer_jwt.signing.key`.

If `filer_jwt.signing.read.key` is configured: When sending GET or HEAD requests to a filer server, the request header `Authorization` should be the JWT string (`Authorization: Bearer [JwtToken]`). The operation is authorized after the filer validates the JWT with `filer_jwt.signing.read.key`.

The S3 API Gateway reads the above JWT keys and sends authenticated
HTTP requests to the filer.
```

Page `Security Configuration`:

```
(update scaffold file)

...

[filer_jwt.signing]
key = "blahblahblahblah"

[filer_jwt.signing.read]
key = "blahblahblahblah"
```

Resolves: #158

weed/command/scaffold/security.toml

@@ -4,24 +4,46 @@
 #    /etc/seaweedfs/security.toml
 # this file is read by master, volume server, and filer
 
-# the jwt signing key is read by master and volume server.
-# a jwt defaults to expire after 10 seconds.
+# this jwt signing key is read by master and volume server, and it is used for write operations:
+# - the Master server generates the JWT, which can be used to write a certain file on a volume server
+# - the Volume server validates the JWT on writing
+# the jwt defaults to expire after 10 seconds.
 [jwt.signing]
 key = ""
 expires_after_seconds = 10           # seconds
 
 # by default, if the signing key above is set, the Volume UI over HTTP is disabled.
 # by setting ui.access to true, you can re-enable the Volume UI. Despite
-# some information leakage (as the UI is unauthenticted), this should not
+# some information leakage (as the UI is not authenticated), this should not
 # pose a security risk.
 [access]
 ui = false
 
-# jwt for read is only supported with master+volume setup. Filer does not support this mode.
+# this jwt signing key is read by master and volume server, and it is used for read operations:
+# - the Master server generates the JWT, which can be used to read a certain file on a volume server
+# - the Volume server validates the JWT on reading
+# NOTE: jwt for read is only supported with master+volume setup. Filer does not support this mode.
 [jwt.signing.read]
 key = ""
 expires_after_seconds = 10           # seconds
 
+
+# If this JWT key is configured, Filer only accepts writes over HTTP if they are signed with this JWT:
+# - f.e. the S3 API Shim generates the JWT
+# - the Filer server validates the JWT on writing
+# the jwt defaults to expire after 10 seconds.
+[filer_jwt.signing]
+key = ""
+expires_after_seconds = 10           # seconds
+
+# If this JWT key is configured, Filer only accepts reads over HTTP if they are signed with this JWT:
+# - f.e. the S3 API Shim generates the JWT
+# - the Filer server validates the JWT on writing
+# the jwt defaults to expire after 10 seconds.
+[filer_jwt.signing.read]
+key = ""
+expires_after_seconds = 10           # seconds
+
 # all grpc tls authentications are mutual
 # the values for the following ca, cert, and key are paths to the PERM files.
 # the host name is not checked, so the PERM files can be shared.

weed/s3api/s3api_object_copy_handlers.go

@@ -74,7 +74,7 @@ func (s3a *S3ApiServer) CopyObjectHandler(w http.ResponseWriter, r *http.Request
 	srcUrl := fmt.Sprintf("http://%s%s/%s%s",
 		s3a.option.Filer.ToHttpAddress(), s3a.option.BucketsPath, srcBucket, urlPathEscape(srcObject))
 
-	_, _, resp, err := util.DownloadFile(srcUrl, "")
+	_, _, resp, err := util.DownloadFile(srcUrl, s3a.maybeGetFilerJwtAuthorizationToken(false))
 	if err != nil {
 		s3err.WriteErrorResponse(w, r, s3err.ErrInvalidCopySource)
 		return
@@ -157,7 +157,7 @@ func (s3a *S3ApiServer) CopyObjectPartHandler(w http.ResponseWriter, r *http.Req
 	srcUrl := fmt.Sprintf("http://%s%s/%s%s",
 		s3a.option.Filer.ToHttpAddress(), s3a.option.BucketsPath, srcBucket, urlPathEscape(srcObject))
 
-	dataReader, err := util.ReadUrlAsReaderCloser(srcUrl, rangeHeader)
+	dataReader, err := util.ReadUrlAsReaderCloser(srcUrl, s3a.maybeGetFilerJwtAuthorizationToken(false), rangeHeader)
 	if err != nil {
 		s3err.WriteErrorResponse(w, r, s3err.ErrInvalidCopySource)
 		return

weed/s3api/s3api_object_handlers.go

@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"encoding/xml"
 	"fmt"
+	"github.com/chrislusf/seaweedfs/weed/security"
 	"io"
 	"net/http"
 	"net/url"
@@ -143,7 +144,7 @@ func (s3a *S3ApiServer) GetObjectHandler(w http.ResponseWriter, r *http.Request)
 	destUrl := fmt.Sprintf("http://%s%s/%s%s",
 		s3a.option.Filer.ToHttpAddress(), s3a.option.BucketsPath, bucket, urlPathEscape(object))
 
-	s3a.proxyToFiler(w, r, destUrl, passThroughResponse)
+	s3a.proxyToFiler(w, r, destUrl, false, passThroughResponse)
 }
 
 func (s3a *S3ApiServer) HeadObjectHandler(w http.ResponseWriter, r *http.Request) {
@@ -154,7 +155,7 @@ func (s3a *S3ApiServer) HeadObjectHandler(w http.ResponseWriter, r *http.Request
 	destUrl := fmt.Sprintf("http://%s%s/%s%s",
 		s3a.option.Filer.ToHttpAddress(), s3a.option.BucketsPath, bucket, urlPathEscape(object))
 
-	s3a.proxyToFiler(w, r, destUrl, passThroughResponse)
+	s3a.proxyToFiler(w, r, destUrl, false, passThroughResponse)
 }
 
 func (s3a *S3ApiServer) DeleteObjectHandler(w http.ResponseWriter, r *http.Request) {
@@ -165,7 +166,7 @@ func (s3a *S3ApiServer) DeleteObjectHandler(w http.ResponseWriter, r *http.Reque
 	destUrl := fmt.Sprintf("http://%s%s/%s%s?recursive=true",
 		s3a.option.Filer.ToHttpAddress(), s3a.option.BucketsPath, bucket, urlPathEscape(object))
 
-	s3a.proxyToFiler(w, r, destUrl, func(proxyResponse *http.Response, w http.ResponseWriter) (statusCode int) {
+	s3a.proxyToFiler(w, r, destUrl, true, func(proxyResponse *http.Response, w http.ResponseWriter) (statusCode int) {
 		statusCode = http.StatusNoContent
 		for k, v := range proxyResponse.Header {
 			w.Header()[k] = v
@@ -306,11 +307,12 @@ func (s3a *S3ApiServer) doDeleteEmptyDirectories(client filer_pb.SeaweedFilerCli
 	return
 }
 
-func (s3a *S3ApiServer) proxyToFiler(w http.ResponseWriter, r *http.Request, destUrl string, responseFn func(proxyResponse *http.Response, w http.ResponseWriter) (statusCode int)) {
+func (s3a *S3ApiServer) proxyToFiler(w http.ResponseWriter, r *http.Request, destUrl string, isWrite bool, responseFn func(proxyResponse *http.Response, w http.ResponseWriter) (statusCode int)) {
 
 	glog.V(3).Infof("s3 proxying %s to %s", r.Method, destUrl)
 
 	proxyReq, err := http.NewRequest(r.Method, destUrl, r.Body)
+	s3a.maybeAddFilerJwtAuthorization(proxyReq, isWrite)
 
 	if err != nil {
 		glog.Errorf("NewRequest %s: %v", destUrl, err)
@@ -374,6 +376,7 @@ func (s3a *S3ApiServer) putToFiler(r *http.Request, uploadUrl string, dataReader
 	var body = io.TeeReader(dataReader, hash)
 
 	proxyReq, err := http.NewRequest("PUT", uploadUrl, body)
+	s3a.maybeAddFilerJwtAuthorization(proxyReq, true)
 
 	if err != nil {
 		glog.Errorf("NewRequest %s: %v", uploadUrl, err)
@@ -433,3 +436,23 @@ func filerErrorToS3Error(errString string) s3err.ErrorCode {
 	}
 	return s3err.ErrInternalError
 }
+
+func (s3a *S3ApiServer) maybeAddFilerJwtAuthorization(r *http.Request, isWrite bool) {
+	encodedJwt := s3a.maybeGetFilerJwtAuthorizationToken(isWrite)
+
+	if encodedJwt == "" {
+		return
+	}
+
+	r.Header.Add("Authorization", "BEARER "+string(encodedJwt))
+}
+
+func (s3a *S3ApiServer) maybeGetFilerJwtAuthorizationToken(isWrite bool) string {
+	var encodedJwt security.EncodedJwt
+	if isWrite {
+		encodedJwt = security.GenJwtForFilerServer(s3a.filerGuard.SigningKey, s3a.filerGuard.ExpiresAfterSec)
+	} else {
+		encodedJwt = security.GenJwtForFilerServer(s3a.filerGuard.ReadSigningKey, s3a.filerGuard.ReadExpiresAfterSec)
+	}
+	return string(encodedJwt)
+}

weed/s3api/s3api_server.go

@@ -3,6 +3,8 @@ package s3api
 import (
 	"fmt"
 	"github.com/chrislusf/seaweedfs/weed/pb"
+	"github.com/chrislusf/seaweedfs/weed/security"
+	"github.com/chrislusf/seaweedfs/weed/util"
 	"net/http"
 	"strings"
 	"time"
@@ -25,14 +27,25 @@ type S3ApiServerOption struct {
 }
 
 type S3ApiServer struct {
-	option *S3ApiServerOption
-	iam    *IdentityAccessManagement
+	option     *S3ApiServerOption
+	iam        *IdentityAccessManagement
+	filerGuard *security.Guard
 }
 
 func NewS3ApiServer(router *mux.Router, option *S3ApiServerOption) (s3ApiServer *S3ApiServer, err error) {
+	v := util.GetViper()
+	signingKey := v.GetString("jwt.filer_signing.key")
+	v.SetDefault("jwt.filer_signing.expires_after_seconds", 10)
+	expiresAfterSec := v.GetInt("jwt.filer_signing.expires_after_seconds")
+
+	readSigningKey := v.GetString("jwt.filer_signing.read.key")
+	v.SetDefault("jwt.filer_signing.read.expires_after_seconds", 60)
+	readExpiresAfterSec := v.GetInt("jwt.filer_signing.read.expires_after_seconds")
+
 	s3ApiServer = &S3ApiServer{
-		option: option,
-		iam:    NewIdentityAccessManagement(option),
+		option:     option,
+		iam:        NewIdentityAccessManagement(option),
+		filerGuard: security.NewGuard([]string{}, signingKey, expiresAfterSec, readSigningKey, readExpiresAfterSec),
 	}
 
 	s3ApiServer.registerRouter(router)

weed/security/jwt.go

@@ -20,6 +20,13 @@ type SeaweedFileIdClaims struct {
 	jwt.StandardClaims
 }
 
+// SeaweedFilerClaims is created e.g. by S3 proxy server and consumed by Filer server.
+// Right now, it only contains the standard claims; but this might be extended later
+// for more fine-grained permissions.
+type SeaweedFilerClaims struct {
+	jwt.StandardClaims
+}
+
 func GenJwtForVolumeServer(signingKey SigningKey, expiresAfterSec int, fileId string) EncodedJwt {
 	if len(signingKey) == 0 {
 		return ""
@@ -41,6 +48,28 @@ func GenJwtForVolumeServer(signingKey SigningKey, expiresAfterSec int, fileId st
 	return EncodedJwt(encoded)
 }
 
+// GenJwtForFilerServer creates a JSON-web-token for using the authenticated Filer API. Used f.e. inside
+// the S3 API
+func GenJwtForFilerServer(signingKey SigningKey, expiresAfterSec int) EncodedJwt {
+	if len(signingKey) == 0 {
+		return ""
+	}
+
+	claims := SeaweedFilerClaims{
+		jwt.StandardClaims{},
+	}
+	if expiresAfterSec > 0 {
+		claims.ExpiresAt = time.Now().Add(time.Second * time.Duration(expiresAfterSec)).Unix()
+	}
+	t := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+	encoded, e := t.SignedString([]byte(signingKey))
+	if e != nil {
+		glog.V(0).Infof("Failed to sign claims %+v: %v", t.Claims, e)
+		return ""
+	}
+	return EncodedJwt(encoded)
+}
+
 func GetJwt(r *http.Request) EncodedJwt {
 
 	// Get token from query params

weed/server/filer_server.go

@@ -71,6 +71,7 @@ type FilerServer struct {
 	option         *FilerOption
 	secret         security.SigningKey
 	filer          *filer.Filer
+	filerGuard     *security.Guard
 	grpcDialOption grpc.DialOption
 
 	// metrics read from the master
@@ -90,6 +91,15 @@ type FilerServer struct {
 
 func NewFilerServer(defaultMux, readonlyMux *http.ServeMux, option *FilerOption) (fs *FilerServer, err error) {
 
+	v := util.GetViper()
+	signingKey := v.GetString("jwt.filer_signing.key")
+	v.SetDefault("jwt.filer_signing.expires_after_seconds", 10)
+	expiresAfterSec := v.GetInt("jwt.filer_signing.expires_after_seconds")
+
+	readSigningKey := v.GetString("jwt.filer_signing.read.key")
+	v.SetDefault("jwt.filer_signing.read.expires_after_seconds", 60)
+	readExpiresAfterSec := v.GetInt("jwt.filer_signing.read.expires_after_seconds")
+
 	fs = &FilerServer{
 		option:                option,
 		grpcDialOption:        security.LoadClientTLS(util.GetViper(), "grpc.filer"),
@@ -106,13 +116,14 @@ func NewFilerServer(defaultMux, readonlyMux *http.ServeMux, option *FilerOption)
 		fs.listenersCond.Broadcast()
 	})
 	fs.filer.Cipher = option.Cipher
+	// we do not support IP whitelist right now
+	fs.filerGuard = security.NewGuard([]string{}, signingKey, expiresAfterSec, readSigningKey, readExpiresAfterSec)
 
 	fs.checkWithMaster()
 
 	go stats.LoopPushingMetric("filer", string(fs.option.Host), fs.metricsAddress, fs.metricsIntervalSec)
 	go fs.filer.KeepMasterClientConnected()
 
-	v := util.GetViper()
 	if !util.LoadConfiguration("filer", false) {
 		v.Set("leveldb2.enabled", true)
 		v.Set("leveldb2.dir", option.DefaultLevelDbDir)

weed/server/filer_server_handlers.go

@@ -1,7 +1,9 @@
 package weed_server
 
 import (
+	"errors"
 	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/security"
 	"github.com/chrislusf/seaweedfs/weed/util"
 	"net/http"
 	"strings"
@@ -15,6 +17,19 @@ func (fs *FilerServer) filerHandler(w http.ResponseWriter, r *http.Request) {
 
 	start := time.Now()
 
+	if r.Method == "OPTIONS" {
+		stats.FilerRequestCounter.WithLabelValues("options").Inc()
+		OptionsHandler(w, r, false)
+		stats.FilerRequestHistogram.WithLabelValues("options").Observe(time.Since(start).Seconds())
+		return
+	}
+
+	isReadHttpCall := r.Method == "GET" || r.Method == "HEAD"
+	if !fs.maybeCheckJwtAuthorization(r, !isReadHttpCall) {
+		writeJsonError(w, r, http.StatusUnauthorized, errors.New("wrong jwt"))
+		return
+	}
+
 	// proxy to volume servers
 	var fileId string
 	if strings.HasPrefix(r.RequestURI, "/?proxyChunkId=") {
@@ -78,20 +93,31 @@ func (fs *FilerServer) filerHandler(w http.ResponseWriter, r *http.Request) {
 			fs.PostHandler(w, r, contentLength)
 			stats.FilerRequestHistogram.WithLabelValues("post").Observe(time.Since(start).Seconds())
 		}
-	case "OPTIONS":
-		stats.FilerRequestCounter.WithLabelValues("options").Inc()
-		OptionsHandler(w, r, false)
-		stats.FilerRequestHistogram.WithLabelValues("head").Observe(time.Since(start).Seconds())
 	}
 }
 
 func (fs *FilerServer) readonlyFilerHandler(w http.ResponseWriter, r *http.Request) {
+
+	start := time.Now()
+
+	// We handle OPTIONS first because it never should be authenticated
+	if r.Method == "OPTIONS" {
+		stats.FilerRequestCounter.WithLabelValues("options").Inc()
+		OptionsHandler(w, r, true)
+		stats.FilerRequestHistogram.WithLabelValues("options").Observe(time.Since(start).Seconds())
+		return
+	}
+
+	if !fs.maybeCheckJwtAuthorization(r, false) {
+		writeJsonError(w, r, http.StatusUnauthorized, errors.New("wrong jwt"))
+		return
+	}
+
 	w.Header().Set("Server", "SeaweedFS Filer "+util.VERSION)
 	if r.Header.Get("Origin") != "" {
 		w.Header().Set("Access-Control-Allow-Origin", "*")
 		w.Header().Set("Access-Control-Allow-Credentials", "true")
 	}
-	start := time.Now()
 	switch r.Method {
 	case "GET":
 		stats.FilerRequestCounter.WithLabelValues("get").Inc()
@@ -101,10 +127,6 @@ func (fs *FilerServer) readonlyFilerHandler(w http.ResponseWriter, r *http.Reque
 		stats.FilerRequestCounter.WithLabelValues("head").Inc()
 		fs.GetOrHeadHandler(w, r)
 		stats.FilerRequestHistogram.WithLabelValues("head").Observe(time.Since(start).Seconds())
-	case "OPTIONS":
-		stats.FilerRequestCounter.WithLabelValues("options").Inc()
-		OptionsHandler(w, r, true)
-		stats.FilerRequestHistogram.WithLabelValues("head").Observe(time.Since(start).Seconds())
 	}
 }
 
@@ -116,3 +138,41 @@ func OptionsHandler(w http.ResponseWriter, r *http.Request, isReadOnly bool) {
 	}
 	w.Header().Add("Access-Control-Allow-Headers", "*")
 }
+
+// maybeCheckJwtAuthorization returns true if access should be granted, false if it should be denied
+func (fs *FilerServer) maybeCheckJwtAuthorization(r *http.Request, isWrite bool) bool {
+
+	var signingKey security.SigningKey
+
+	if isWrite {
+		if len(fs.filerGuard.SigningKey) == 0 {
+			return true
+		} else {
+			signingKey = fs.filerGuard.SigningKey
+		}
+	} else {
+		if len(fs.filerGuard.ReadSigningKey) == 0 {
+			return true
+		} else {
+			signingKey = fs.filerGuard.ReadSigningKey
+		}
+	}
+
+	tokenStr := security.GetJwt(r)
+	if tokenStr == "" {
+		glog.V(1).Infof("missing jwt from %s", r.RemoteAddr)
+		return false
+	}
+
+	token, err := security.DecodeJwt(signingKey, tokenStr, &security.SeaweedFilerClaims{})
+	if err != nil {
+		glog.V(1).Infof("jwt verification error from %s: %v", r.RemoteAddr, err)
+		return false
+	}
+	if !token.Valid {
+		glog.V(1).Infof("jwt invalid from %s: %v", r.RemoteAddr, tokenStr)
+		return false
+	} else {
+		return true
+	}
+}

weed/util/http_util.go

@@ -180,7 +180,16 @@ func GetUrlStream(url string, values url.Values, readFn func(io.Reader) error) e
 }
 
 func DownloadFile(fileUrl string, jwt string) (filename string, header http.Header, resp *http.Response, e error) {
-	response, err := client.Get(fileUrl)
+	req, err := http.NewRequest("GET", fileUrl, nil)
+	if err != nil {
+		return "", nil, nil, err
+	}
+
+	if len(jwt) > 0 {
+		req.Header.Add("Authorization", "BEARER "+jwt)
+	}
+
+	response, err := client.Do(req)
 	if err != nil {
 		return "", nil, nil, err
 	}
@@ -358,7 +367,7 @@ func readEncryptedUrl(fileUrl string, cipherKey []byte, isContentCompressed bool
 	return false, nil
 }
 
-func ReadUrlAsReaderCloser(fileUrl string, rangeHeader string) (io.ReadCloser, error) {
+func ReadUrlAsReaderCloser(fileUrl string, jwt string, rangeHeader string) (io.ReadCloser, error) {
 
 	req, err := http.NewRequest("GET", fileUrl, nil)
 	if err != nil {
@@ -370,6 +379,10 @@ func ReadUrlAsReaderCloser(fileUrl string, rangeHeader string) (io.ReadCloser, e
 		req.Header.Add("Accept-Encoding", "gzip")
 	}
 
+	if len(jwt) > 0 {
+		req.Header.Add("Authorization", "BEARER "+jwt)
+	}
+
 	r, err := client.Do(req)
 	if err != nil {
 		return nil, err