fixed JWT authentication port (#3689)

* fixed JWT

* jwt.hex

* ops

cmd/rpcdaemon/cli/config.go

@@ -4,8 +4,8 @@ import (
 	"context"
 	"crypto/rand"
 	"encoding/binary"
+	"errors"
 	"fmt"
-	"io/ioutil"
 	"net"
 	"net/http"
 	"os"
@@ -32,6 +32,7 @@ import (
 	"github.com/ledgerwatch/erigon/cmd/rpcdaemon/services"
 	"github.com/ledgerwatch/erigon/cmd/utils"
 	"github.com/ledgerwatch/erigon/common"
+	"github.com/ledgerwatch/erigon/common/hexutil"
 	"github.com/ledgerwatch/erigon/common/paths"
 	"github.com/ledgerwatch/erigon/core/rawdb"
 	"github.com/ledgerwatch/erigon/eth/ethconfig"
@@ -517,35 +518,44 @@ func isWebsocket(r *http.Request) bool {
 		strings.Contains(strings.ToLower(r.Header.Get("Connection")), "upgrade")
 }
 
-func createHandler(cfg httpcfg.HttpCfg, apiList []rpc.API, httpHandler http.Handler, wsHandler http.Handler, isAuth bool) (http.Handler, error) {
-	var jwtVerificationKey []byte
-	var err error
-
-	if isAuth {
-		// If no file is specified we generate a key in jwt.hex
-		if cfg.JWTSecretPath == "" {
-			jwtVerificationKey := make([]byte, 32)
-			rand.Read(jwtVerificationKey)
-			jwtVerificationKey = []byte(common.Bytes2Hex(jwtVerificationKey))
-			f, err := os.Create(JwtDefaultFile)
-			if err != nil {
-				return nil, err
-			}
-			defer f.Close()
-
-			_, err = f.Write(jwtVerificationKey)
-			if err != nil {
-				return nil, err
-			}
-		} else {
-			jwtVerificationKey, err = ioutil.ReadFile(cfg.JWTSecretPath)
-			if err != nil {
-				return nil, err
-			}
-			if len(jwtVerificationKey) != 64 {
-				return nil, fmt.Errorf("error: invalid size of verification key in %s", cfg.JWTSecretPath)
-			}
+// obtainJWTSecret loads the jwt-secret, either from the provided config,
+// or from the default location. If neither of those are present, it generates
+// a new secret and stores to the default location.
+func obtainJWTSecret(cfg httpcfg.HttpCfg) ([]byte, error) {
+	var fileName string
+	if len(cfg.JWTSecretPath) > 0 {
+		// path provided
+		fileName = cfg.JWTSecretPath
+	} else {
+		// no path provided, use default
+		fileName = JwtDefaultFile
+	}
+	// try reading from file
+	log.Info("Reading JWT secret", "path", fileName)
+	if data, err := os.ReadFile(fileName); err == nil {
+		jwtSecret := common.FromHex(strings.TrimSpace(string(data)))
+		if len(jwtSecret) == 32 {
+			return jwtSecret, nil
 		}
+		log.Error("Invalid JWT secret", "path", fileName, "length", len(jwtSecret))
+		return nil, errors.New("invalid JWT secret")
+	}
+	// Need to generate one
+	jwtSecret := make([]byte, 32)
+	rand.Read(jwtSecret)
+
+	if err := os.WriteFile(fileName, []byte(hexutil.Encode(jwtSecret)), 0600); err != nil {
+		return nil, err
+	}
+	log.Info("Generated JWT secret", "path", fileName)
+	return jwtSecret, nil
+}
+
+func createHandler(cfg httpcfg.HttpCfg, apiList []rpc.API, httpHandler http.Handler, wsHandler http.Handler, isAuth bool) (http.Handler, error) {
+	// Finds jwt secret
+	jwtVerificationKey, err := obtainJWTSecret(cfg)
+	if err != nil {
+		return nil, err
 	}
 
 	var handler http.Handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
@@ -559,26 +569,41 @@ func createHandler(cfg httpcfg.HttpCfg, apiList []rpc.API, httpHandler http.Hand
 		}
 
 		if isAuth {
+			var tokenStr string
 			// Check if JWT signature is correct
-			tokenStr, ok := r.Header["Authorization"]
-			if !ok {
-				w.WriteHeader(http.StatusBadRequest)
+			if auth := r.Header.Get("Authorization"); strings.HasPrefix(auth, "Bearer ") {
+				tokenStr = strings.TrimPrefix(auth, "Bearer ")
+			}
+
+			if len(tokenStr) == 0 {
+				http.Error(w, "missing token", http.StatusForbidden)
 				return
 			}
 
-			claims := jwt.StandardClaims{}
-			tkn, err := jwt.ParseWithClaims(strings.Replace(tokenStr[0], "Bearer ", "", 1), &claims, func(token *jwt.Token) (interface{}, error) {
+			keyFunc := func(token *jwt.Token) (interface{}, error) {
 				return jwtVerificationKey, nil
-			})
-			if err != nil || !tkn.Valid {
-				w.WriteHeader(http.StatusUnauthorized)
-				return
 			}
-			// Validate time of iat
-			now := time.Now().Unix()
-			if claims.IssuedAt > now+JwtTokenExpiry.Nanoseconds() && claims.IssuedAt < now-JwtTokenExpiry.Nanoseconds() {
-				w.WriteHeader(http.StatusUnauthorized)
-				return
+			claims := jwt.RegisteredClaims{}
+			// We explicitly set only HS256 allowed, and also disables the
+			// claim-check: the RegisteredClaims internally requires 'iat' to
+			// be no later than 'now', but we allow for a bit of drift.
+			token, err := jwt.ParseWithClaims(tokenStr, &claims, keyFunc,
+				jwt.WithValidMethods([]string{"HS256"}),
+				jwt.WithoutClaimsValidation())
+
+			switch {
+			case err != nil:
+				http.Error(w, err.Error(), http.StatusForbidden)
+			case !token.Valid:
+				http.Error(w, "invalid token", http.StatusForbidden)
+			case !claims.VerifyExpiresAt(time.Now(), false): // optional
+				http.Error(w, "token is expired", http.StatusForbidden)
+			case claims.IssuedAt == nil:
+				http.Error(w, "missing issued-at", http.StatusForbidden)
+			case time.Since(claims.IssuedAt.Time) > JwtTokenExpiry:
+				http.Error(w, "stale token", http.StatusForbidden)
+			case time.Until(claims.IssuedAt.Time) > JwtTokenExpiry:
+				http.Error(w, "future token", http.StatusForbidden)
 			}
 		}