imported jwt module

jwt/util.go

@@ -0,0 +1,123 @@
+package jwt
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/golang-jwt/jwt"
+	"github.com/google/uuid"
+	"github.com/pkg/errors"
+)
+
+// Parse a token, validating its signing sigature and returning the claims
+func parseToken(secretKey string, tokenString string) (jwt.MapClaims, error) {
+	token, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
+		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
+			return nil, fmt.Errorf("Unexpected signing method: %v", token.Header["alg"])
+		}
+
+		return []byte(secretKey), nil
+	})
+	if err != nil {
+		return nil, errors.Wrap(err, "jwt.Parse")
+	}
+	// Token decoded, parse the claims
+	claims, ok := token.Claims.(jwt.MapClaims)
+	if !ok {
+		return nil, errors.New("Failed to parse claims")
+	}
+	return claims, nil
+}
+
+// Check if a token is expired. Returns the expiry if not expired
+func checkTokenExpired(expiry interface{}) (int64, error) {
+	// Coerce the expiry to a float64 to avoid scientific notation
+	expFloat, ok := expiry.(float64)
+	if !ok {
+		return 0, errors.New("Missing or invalid 'exp' claim")
+	}
+	// Convert to the int64 time we expect :)
+	expiryTime := int64(expFloat)
+
+	// Check if its expired
+	isExpired := time.Now().After(time.Unix(expiryTime, 0))
+	if isExpired {
+		return 0, errors.New("Token has expired")
+	}
+	return expiryTime, nil
+}
+
+// Check if a token has a valid issuer. Returns the issuer if valid
+func checkTokenIssuer(trustedHost string, issuer interface{}) (string, error) {
+	issuerVal, ok := issuer.(string)
+	if !ok {
+		return "", errors.New("Missing or invalid 'iss' claim")
+	}
+	if issuer != trustedHost {
+		return "", errors.New("Issuer does not matched trusted host")
+	}
+	return issuerVal, nil
+}
+
+// Check the scope matches the expected scope. Returns scope if true
+func getTokenScope(scope interface{}) (string, error) {
+	scopeStr, ok := scope.(string)
+	if !ok {
+		return "", errors.New("Missing or invalid 'scope' claim")
+	}
+	return scopeStr, nil
+}
+
+// Get the TTL of the token, either "session" or "exp"
+func getTokenTTL(ttl interface{}) (string, error) {
+	ttlStr, ok := ttl.(string)
+	if !ok {
+		return "", errors.New("Missing or invalid 'ttl' claim")
+	}
+	if ttlStr != "exp" && ttlStr != "session" {
+		return "", errors.New("TTL value is not recognised")
+	}
+	return ttlStr, nil
+}
+
+// Get the time the token was issued at
+func getIssuedTime(issued interface{}) (int64, error) {
+	// Same float64 -> int64 trick as expiry
+	issuedFloat, ok := issued.(float64)
+	if !ok {
+		return 0, errors.New("Missing or invalid 'iat' claim")
+	}
+	issuedAt := int64(issuedFloat)
+	return issuedAt, nil
+}
+
+// Get the freshness expiry timestamp
+func getFreshTime(fresh interface{}) (int64, error) {
+	freshUntil, ok := fresh.(float64)
+	if !ok {
+		return 0, errors.New("Missing or invalid 'fresh' claim")
+	}
+	return int64(freshUntil), nil
+}
+
+// Get the subject of the token
+func getTokenSubject(sub interface{}) (int, error) {
+	subject, ok := sub.(float64)
+	if !ok {
+		return 0, errors.New("Missing or invalid 'sub' claim")
+	}
+	return int(subject), nil
+}
+
+// Get the JTI of the token
+func getTokenJTI(jti interface{}) (uuid.UUID, error) {
+	jtiStr, ok := jti.(string)
+	if !ok {
+		return uuid.UUID{}, errors.New("Missing or invalid 'jti' claim")
+	}
+	jtiUUID, err := uuid.Parse(jtiStr)
+	if err != nil {
+		return uuid.UUID{}, errors.New("JTI is not a valid UUID")
+	}
+	return jtiUUID, nil
+}