package oidcauth import ( "context" "crypto/ecdsa" "crypto/ed25519" "crypto/rsa" "crypto/x509" "encoding/json" "encoding/pem" "errors" "fmt" "time" "gopkg.in/square/go-jose.v2/jwt" ) const claimDefaultLeeway = 150 // ClaimsFromJWT is unrelated to the OIDC authorization code workflow. This // allows for a JWT to be directly validated and decoded into a set of claims. // // Requires the authenticator's config type be set to 'jwt'. func (a *Authenticator) ClaimsFromJWT(ctx context.Context, jwt string) (*Claims, error) { if a.config.authType() == authOIDCFlow { return nil, fmt.Errorf("ClaimsFromJWT is incompatible with type %q", TypeOIDC) } if jwt == "" { return nil, errors.New("missing jwt") } // Here is where things diverge. If it is using OIDC Discovery, validate that way; // otherwise validate against the locally configured or JWKS keys. Once things are // validated, we re-unify the request path when evaluating the claims. var ( allClaims map[string]interface{} err error ) switch a.config.authType() { case authStaticKeys, authJWKS: allClaims, err = a.verifyVanillaJWT(ctx, jwt) if err != nil { return nil, err } case authOIDCDiscovery: allClaims, err = a.verifyOIDCToken(ctx, jwt) if err != nil { return nil, err } default: return nil, errors.New("unhandled case during login") } c, err := a.extractClaims(allClaims) if err != nil { return nil, err } if a.config.VerboseOIDCLogging && a.logger != nil { a.logger.Debug("OIDC provider response", "extracted_claims", c) } return c, nil } func (a *Authenticator) verifyVanillaJWT(ctx context.Context, loginToken string) (map[string]interface{}, error) { var ( allClaims = map[string]interface{}{} claims = jwt.Claims{} ) // TODO(sso): handle JWTSupportedAlgs switch a.config.authType() { case authJWKS: // Verify signature (and only signature... other elements are checked later) payload, err := a.keySet.VerifySignature(ctx, loginToken) if err != nil { return nil, fmt.Errorf("error verifying token: %v", err) } // Unmarshal payload into two copies: public claims for library verification, and a set // of all received claims. if err := json.Unmarshal(payload, &claims); err != nil { return nil, fmt.Errorf("failed to unmarshal claims: %v", err) } if err := json.Unmarshal(payload, &allClaims); err != nil { return nil, fmt.Errorf("failed to unmarshal claims: %v", err) } case authStaticKeys: parsedJWT, err := jwt.ParseSigned(loginToken) if err != nil { return nil, fmt.Errorf("error parsing token: %v", err) } var valid bool for _, key := range a.parsedJWTPubKeys { if err := parsedJWT.Claims(key, &claims, &allClaims); err == nil { valid = true break } } if !valid { return nil, errors.New("no known key successfully validated the token signature") } default: return nil, fmt.Errorf("unsupported auth type for this verifyVanillaJWT: %d", a.config.authType()) } // We require notbefore or expiry; if only one is provided, we allow 5 minutes of leeway by default. // Configurable by ExpirationLeeway and NotBeforeLeeway if claims.IssuedAt == nil { claims.IssuedAt = new(jwt.NumericDate) } if claims.Expiry == nil { claims.Expiry = new(jwt.NumericDate) } if claims.NotBefore == nil { claims.NotBefore = new(jwt.NumericDate) } if *claims.IssuedAt == 0 && *claims.Expiry == 0 && *claims.NotBefore == 0 { return nil, errors.New("no issue time, notbefore, or expiration time encoded in token") } if *claims.Expiry == 0 { latestStart := *claims.IssuedAt if *claims.NotBefore > *claims.IssuedAt { latestStart = *claims.NotBefore } leeway := a.config.ExpirationLeeway.Seconds() if a.config.ExpirationLeeway.Seconds() < 0 { leeway = 0 } else if a.config.ExpirationLeeway.Seconds() == 0 { leeway = claimDefaultLeeway } *claims.Expiry = jwt.NumericDate(int64(latestStart) + int64(leeway)) } if *claims.NotBefore == 0 { if *claims.IssuedAt != 0 { *claims.NotBefore = *claims.IssuedAt } else { leeway := a.config.NotBeforeLeeway.Seconds() if a.config.NotBeforeLeeway.Seconds() < 0 { leeway = 0 } else if a.config.NotBeforeLeeway.Seconds() == 0 { leeway = claimDefaultLeeway } *claims.NotBefore = jwt.NumericDate(int64(*claims.Expiry) - int64(leeway)) } } expected := jwt.Expected{ Issuer: a.config.BoundIssuer, // Subject: a.config.BoundSubject, Time: time.Now(), } cksLeeway := a.config.ClockSkewLeeway if a.config.ClockSkewLeeway.Seconds() < 0 { cksLeeway = 0 } else if a.config.ClockSkewLeeway.Seconds() == 0 { cksLeeway = jwt.DefaultLeeway } if err := claims.ValidateWithLeeway(expected, cksLeeway); err != nil { return nil, fmt.Errorf("error validating claims: %v", err) } if err := validateAudience(a.config.BoundAudiences, claims.Audience, true); err != nil { return nil, fmt.Errorf("error validating claims: %v", err) } return allClaims, nil } // parsePublicKeyPEM is used to parse RSA, ECDSA, and Ed25519 public keys from PEMs // // Extracted from "github.com/hashicorp/vault/sdk/helper/certutil" // // go-sso added support for ed25519 (EdDSA) func parsePublicKeyPEM(data []byte) (interface{}, error) { block, _ := pem.Decode(data) if block != nil { var rawKey interface{} var err error if rawKey, err = x509.ParsePKIXPublicKey(block.Bytes); err != nil { if cert, err := x509.ParseCertificate(block.Bytes); err == nil { rawKey = cert.PublicKey } else { return nil, err } } if rsaPublicKey, ok := rawKey.(*rsa.PublicKey); ok { return rsaPublicKey, nil } if ecPublicKey, ok := rawKey.(*ecdsa.PublicKey); ok { return ecPublicKey, nil } if edPublicKey, ok := rawKey.(ed25519.PublicKey); ok { return edPublicKey, nil } } return nil, errors.New("data does not contain any valid RSA, ECDSA, or ED25519 public keys") }