Replace *jwt.validateClaimsWithLeeway with custom validation func

+ refactor validator pkg
auth0 · Oct 31, 2022 · 33c3d1d · 33c3d1d
1 parent 6f70e49
commit 33c3d1d
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Showing 2 changed files with 134 additions and 42 deletions.
diff --git a/validator/validator.go b/validator/validator.go
@@ -99,62 +99,114 @@ func (v *Validator) ValidateToken(ctx context.Context, tokenString string) (inte
 		return nil, fmt.Errorf("could not parse the token: %w", err)
 	}
 
-	if string(v.signatureAlgorithm) != token.Headers[0].Algorithm {
-		return nil, fmt.Errorf(
-			"expected %q signing algorithm but token specified %q",
-			v.signatureAlgorithm,
-			token.Headers[0].Algorithm,
-		)
+	if err = validateSigningMethod(string(v.signatureAlgorithm), token.Headers[0].Algorithm); err != nil {
+		return nil, fmt.Errorf("signing method is invalid: %w", err)
 	}
 
-	key, err := v.keyFunc(ctx)
+	registeredClaims, customClaims, err := v.deserializeClaims(ctx, token)
 	if err != nil {
-		return nil, fmt.Errorf("error getting the keys from the key func: %w", err)
-	}
-
-	claimDest := []interface{}{&jwt.Claims{}}
-	if v.customClaims != nil && v.customClaims() != nil {
-		claimDest = append(claimDest, v.customClaims())
+		return nil, fmt.Errorf("failed to deserialize token claims: %w", err)
 	}
 
-	if err = token.Claims(key, claimDest...); err != nil {
-		return nil, fmt.Errorf("could not get token claims: %w", err)
+	if err = validateClaimsWithLeeway(registeredClaims, v.expectedClaims, v.allowedClockSkew); err != nil {
+		return nil, fmt.Errorf("expected claims not validated: %w", err)
 	}
 
-	registeredClaims := *claimDest[0].(*jwt.Claims)
-	expectedClaims := v.expectedClaims
-	expectedClaims.Time = time.Now()
-	if err = registeredClaims.ValidateWithLeeway(expectedClaims, v.allowedClockSkew); err != nil {
-		return nil, fmt.Errorf("expected claims not validated: %w", err)
+	if customClaims != nil {
+		if err = customClaims.Validate(ctx); err != nil {
+			return nil, fmt.Errorf("custom claims not validated: %w", err)
+		}
 	}
 
 	validatedClaims := &ValidatedClaims{
 		RegisteredClaims: RegisteredClaims{
-			Issuer:   registeredClaims.Issuer,
-			Subject:  registeredClaims.Subject,
-			Audience: registeredClaims.Audience,
-			ID:       registeredClaims.ID,
+			Issuer:    registeredClaims.Issuer,
+			Subject:   registeredClaims.Subject,
+			Audience:  registeredClaims.Audience,
+			ID:        registeredClaims.ID,
+			Expiry:    numericDateToUnixTime(registeredClaims.Expiry),
+			NotBefore: numericDateToUnixTime(registeredClaims.NotBefore),
+			IssuedAt:  numericDateToUnixTime(registeredClaims.IssuedAt),
 		},
+		CustomClaims: customClaims,
 	}
 
-	if registeredClaims.Expiry != nil {
-		validatedClaims.RegisteredClaims.Expiry = registeredClaims.Expiry.Time().Unix()
+	return validatedClaims, nil
+}
+
+func validateClaimsWithLeeway(actualClaims jwt.Claims, expected jwt.Expected, leeway time.Duration) error {
+	expectedClaims := expected
+	expectedClaims.Time = time.Now()
+
+	if actualClaims.Issuer != expectedClaims.Issuer {
+		return jwt.ErrInvalidIssuer
 	}
 
-	if registeredClaims.NotBefore != nil {
-		validatedClaims.RegisteredClaims.NotBefore = registeredClaims.NotBefore.Time().Unix()
+	foundAudience := false
+	for _, value := range expectedClaims.Audience {
+		if actualClaims.Audience.Contains(value) {
+			foundAudience = true
+			break
+		}
+	}
+	if !foundAudience {
+		return jwt.ErrInvalidAudience
 	}
 
-	if registeredClaims.IssuedAt != nil {
-		validatedClaims.RegisteredClaims.IssuedAt = registeredClaims.IssuedAt.Time().Unix()
+	if actualClaims.NotBefore != nil && expectedClaims.Time.Add(leeway).Before(actualClaims.NotBefore.Time()) {
+		return jwt.ErrNotValidYet
 	}
 
-	if v.customClaims != nil && v.customClaims() != nil {
-		validatedClaims.CustomClaims = claimDest[1].(CustomClaims)
-		if err = validatedClaims.CustomClaims.Validate(ctx); err != nil {
-			return nil, fmt.Errorf("custom claims not validated: %w", err)
-		}
+	if actualClaims.Expiry != nil && expectedClaims.Time.Add(-leeway).After(actualClaims.Expiry.Time()) {
+		return jwt.ErrExpired
 	}
 
-	return validatedClaims, nil
+	if actualClaims.IssuedAt != nil && expectedClaims.Time.Add(leeway).Before(actualClaims.IssuedAt.Time()) {
+		return jwt.ErrIssuedInTheFuture
+	}
+
+	return nil
+}
+
+func validateSigningMethod(validAlg, tokenAlg string) error {
+	if validAlg != tokenAlg {
+		return fmt.Errorf("expected %q signing algorithm but token specified %q", validAlg, tokenAlg)
+	}
+	return nil
+}
+
+func (v *Validator) customClaimsExist() bool {
+	return v.customClaims != nil && v.customClaims() != nil
+}
+
+func (v *Validator) deserializeClaims(ctx context.Context, token *jwt.JSONWebToken) (jwt.Claims, CustomClaims, error) {
+	key, err := v.keyFunc(ctx)
+	if err != nil {
+		return jwt.Claims{}, nil, fmt.Errorf("error getting the keys from the key func: %w", err)
+	}
+
+	claims := []interface{}{&jwt.Claims{}}
+	if v.customClaimsExist() {
+		claims = append(claims, v.customClaims())
+	}
+
+	if err = token.Claims(key, claims...); err != nil {
+		return jwt.Claims{}, nil, fmt.Errorf("could not get token claims: %w", err)
+	}
+
+	registeredClaims := *claims[0].(*jwt.Claims)
+
+	var customClaims CustomClaims
+	if len(claims) > 1 {
+		customClaims = claims[1].(CustomClaims)
+	}
+
+	return registeredClaims, customClaims, nil
+}
+
+func numericDateToUnixTime(date *jwt.NumericDate) int64 {
+	if date != nil {
+		return date.Time().Unix()
+	}
+	return 0
 }
diff --git a/validator/validator_test.go b/validator/validator_test.go
@@ -3,10 +3,13 @@ package validator
 import (
 	"context"
 	"errors"
+	"fmt"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"gopkg.in/square/go-jose.v2/jwt"
 )
 
 type testClaims struct {
@@ -77,7 +80,7 @@ func TestValidator_ValidateToken(t *testing.T) {
 				return []byte("secret"), nil
 			},
 			algorithm:     RS256,
-			expectedError: errors.New(`expected "RS256" signing algorithm but token specified "HS256"`),
+			expectedError: errors.New(`signing method is invalid: expected "RS256" signing algorithm but token specified "HS256"`),
 		},
 		{
 			name:  "it throws an error when it cannot parse the token",
@@ -95,7 +98,7 @@ func TestValidator_ValidateToken(t *testing.T) {
 				return nil, errors.New("key func error message")
 			},
 			algorithm:     HS256,
-			expectedError: errors.New("error getting the keys from the key func: key func error message"),
+			expectedError: errors.New("failed to deserialize token claims: error getting the keys from the key func: key func error message"),
 		},
 		{
 			name:  "it throws an error when it fails to deserialize the claims because the signature is invalid",
@@ -104,7 +107,7 @@ func TestValidator_ValidateToken(t *testing.T) {
 				return []byte("secret"), nil
 			},
 			algorithm:     HS256,
-			expectedError: errors.New("could not get token claims: square/go-jose: error in cryptographic primitive"),
+			expectedError: errors.New("failed to deserialize token claims: could not get token claims: square/go-jose: error in cryptographic primitive"),
 		},
 		{
 			name:  "it throws an error when it fails to validate the registered claims",
@@ -150,7 +153,7 @@ func TestValidator_ValidateToken(t *testing.T) {
 		},
 		{
 			name:  "it successfully validates a token with exp, nbf and iat",
-			token: "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwczovL2dvLWp3dC1taWRkbGV3YXJlLmV1LmF1dGgwLmNvbS8iLCJzdWIiOiIxMjM0NTY3ODkwIiwiYXVkIjpbImh0dHBzOi8vZ28tand0LW1pZGRsZXdhcmUtYXBpLyJdLCJpYXQiOjE2NjY5Mzc2ODYsIm5iZiI6MTY2NjkzOTAwMCwiZXhwIjoxNjY3OTM3Njg2fQ.36iSr7w8Q6b9iJoJo-swmfgAfm23w8SlX92NHIHGX2s",
+			token: "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwczovL2dvLWp3dC1taWRkbGV3YXJlLmV1LmF1dGgwLmNvbS8iLCJzdWIiOiIxMjM0NTY3ODkwIiwiYXVkIjpbImh0dHBzOi8vZ28tand0LW1pZGRsZXdhcmUtYXBpLyJdLCJpYXQiOjE2NjY5Mzc2ODYsIm5iZiI6MTY2NjkzOTAwMCwiZXhwIjo5NjY3OTM3Njg2fQ.FKZogkm08gTfYfPU6eYu7OHCjJKnKGLiC0IfoIOPEhs",
 			keyFunc: func(context.Context) (interface{}, error) {
 				return []byte("secret"), nil
 			},
@@ -160,12 +163,48 @@ func TestValidator_ValidateToken(t *testing.T) {
 					Issuer:    issuer,
 					Subject:   subject,
 					Audience:  []string{audience},
-					Expiry:    1667937686,
+					Expiry:    9667937686,
 					NotBefore: 1666939000,
 					IssuedAt:  1666937686,
 				},
 			},
 		},
+		{
+			name:  "it throws an error when token is not valid yet",
+			token: "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwczovL2dvLWp3dC1taWRkbGV3YXJlLmV1LmF1dGgwLmNvbS8iLCJzdWIiOiIxMjM0NTY3ODkwIiwiYXVkIjpbImh0dHBzOi8vZ28tand0LW1pZGRsZXdhcmUtYXBpLyJdLCJpYXQiOjE2NjY5Mzc2ODYsIm5iZiI6OTY2NjkzOTAwMCwiZXhwIjoxNjY3OTM3Njg2fQ.yUizJ-zK_33tv1qBVvDKO0RuCWtvJ02UQKs8gBadgGY",
+			keyFunc: func(context.Context) (interface{}, error) {
+				return []byte("secret"), nil
+			},
+			algorithm:     HS256,
+			expectedError: fmt.Errorf("expected claims not validated: %s", jwt.ErrNotValidYet),
+		},
+		{
+			name:  "it throws an error when token is expired",
+			token: "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwczovL2dvLWp3dC1taWRkbGV3YXJlLmV1LmF1dGgwLmNvbS8iLCJzdWIiOiIxMjM0NTY3ODkwIiwiYXVkIjpbImh0dHBzOi8vZ28tand0LW1pZGRsZXdhcmUtYXBpLyJdLCJpYXQiOjE2NjY5Mzc2ODYsIm5iZiI6MTY2NjkzOTAwMCwiZXhwIjo2Njc5Mzc2ODZ9.SKvz82VOXRi_sjvZWIsPG9vSWAXKKgVS4DkGZcwFKL8",
+			keyFunc: func(context.Context) (interface{}, error) {
+				return []byte("secret"), nil
+			},
+			algorithm:     HS256,
+			expectedError: fmt.Errorf("expected claims not validated: %s", jwt.ErrExpired),
+		},
+		{
+			name:  "it throws an error when token is issued in the future",
+			token: "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwczovL2dvLWp3dC1taWRkbGV3YXJlLmV1LmF1dGgwLmNvbS8iLCJzdWIiOiIxMjM0NTY3ODkwIiwiYXVkIjpbImh0dHBzOi8vZ28tand0LW1pZGRsZXdhcmUtYXBpLyJdLCJpYXQiOjkxNjY2OTM3Njg2LCJuYmYiOjE2NjY5MzkwMDAsImV4cCI6ODY2NzkzNzY4Nn0.ieFV7XNJxiJyw8ARq9yHw-01Oi02e3P2skZO10ypxL8",
+			keyFunc: func(context.Context) (interface{}, error) {
+				return []byte("secret"), nil
+			},
+			algorithm:     HS256,
+			expectedError: fmt.Errorf("expected claims not validated: %s", jwt.ErrIssuedInTheFuture),
+		},
+		{
+			name:  "it throws an error when token issuer is invalid",
+			token: "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwczovL2hhY2tlZC1qd3QtbWlkZGxld2FyZS5ldS5hdXRoMC5jb20vIiwic3ViIjoiMTIzNDU2Nzg5MCIsImF1ZCI6WyJodHRwczovL2dvLWp3dC1taWRkbGV3YXJlLWFwaS8iXSwiaWF0Ijo5MTY2NjkzNzY4NiwibmJmIjoxNjY2OTM5MDAwLCJleHAiOjg2Njc5Mzc2ODZ9.b5gXNrUNfd_jyCWZF-6IPK_UFfvTr9wBQk9_QgRQ8rA",
+			keyFunc: func(context.Context) (interface{}, error) {
+				return []byte("secret"), nil
+			},
+			algorithm:     HS256,
+			expectedError: fmt.Errorf("expected claims not validated: %s", jwt.ErrInvalidIssuer),
+		},
 	}
 
 	for _, testCase := range testCases {
@@ -177,8 +216,9 @@ func TestValidator_ValidateToken(t *testing.T) {
 				testCase.keyFunc,
 				testCase.algorithm,
 				issuer,
-				[]string{audience},
+				[]string{audience, "another-audience"},
 				WithCustomClaims(testCase.customClaims),
+				WithAllowedClockSkew(time.Second),
 			)
 			require.NoError(t, err)