fix repos

By default base64 decoder works in non-strict mode which
allows tweaking signatures having padding without failing validation.

This creates a potential problem if application treats token value as an identifier.

For example ES256 signature has length of 64 bytes and two padding symbols (stripped by default).
Therefore its base64-encoded value can only end with A, Q, g and w.
In non-strict mode last symbol could be tweaked resulting in 16 distinct
token values having the same signature and passing validation.

This change adds backward-compatible global config variable DecodeStrict
(similar to existing DecodePaddingAllowed) that enables strict base64 decoder mode.

See also https://github.com/golang/go/issues/15656.

Signed-off-by: Alexander Yastrebov <yastrebov.alex@gmail.com>

MIGRATION_GUIDE.md

@@ -2,18 +2,18 @@
 
 Starting from [v4.0.0](https://github.com/golang-jwt/jwt/releases/tag/v4.0.0), the import path will be:
 
-    "github.com/golang-jwt/jwt/v4"
+    "git.internal/re/jwt/v4"
 
 The `/v4` version will be backwards compatible with existing `v3.x.y` tags in this repo, as well as 
 `github.com/dgrijalva/jwt-go`. For most users this should be a drop-in replacement, if you're having 
 troubles migrating, please open an issue.
 
-You can replace all occurrences of `github.com/dgrijalva/jwt-go` or `github.com/golang-jwt/jwt` with `github.com/golang-jwt/jwt/v4`, either manually or by using tools such as `sed` or `gofmt`.
+You can replace all occurrences of `github.com/dgrijalva/jwt-go` or `github.com/golang-jwt/jwt` with `git.internal/re/jwt/v4`, either manually or by using tools such as `sed` or `gofmt`.
 
 And then you'd typically run:
 
 ```
-go get github.com/golang-jwt/jwt/v4
+go get git.internal/re/jwt/v4
 go mod tidy
 ```
 

README.md

@@ -1,7 +1,7 @@
 # jwt-go
 
 [![build](https://github.com/golang-jwt/jwt/actions/workflows/build.yml/badge.svg)](https://github.com/golang-jwt/jwt/actions/workflows/build.yml)
-[![Go Reference](https://pkg.go.dev/badge/github.com/golang-jwt/jwt/v4.svg)](https://pkg.go.dev/github.com/golang-jwt/jwt/v4)
+[![Go Reference](https://pkg.go.dev/badge/git.internal/re/jwt/v4.svg)](https://pkg.go.dev/git.internal/re/jwt/v4)
 
 A [go](http://www.golang.org) (or 'golang' for search engine friendliness) implementation of [JSON Web Tokens](https://datatracker.ietf.org/doc/html/rfc7519).
 
@@ -41,22 +41,22 @@ This library supports the parsing and verification as well as the generation and
 1. To install the jwt package, you first need to have [Go](https://go.dev/doc/install) installed, then you can use the command below to add `jwt-go` as a dependency in your Go program.
 
 ```sh
-go get -u github.com/golang-jwt/jwt/v4
+go get -u git.internal/re/jwt/v4
 ```
 
 2. Import it in your code:
 
 ```go
-import "github.com/golang-jwt/jwt/v4"
+import "git.internal/re/jwt/v4"
 ```
 
 ## Examples
 
-See [the project documentation](https://pkg.go.dev/github.com/golang-jwt/jwt/v4) for examples of usage:
+See [the project documentation](https://pkg.go.dev/git.internal/re/jwt/v4) for examples of usage:
 
-* [Simple example of parsing and validating a token](https://pkg.go.dev/github.com/golang-jwt/jwt/v4#example-Parse-Hmac)
+* [Simple example of parsing and validating a token](https://pkg.go.dev/git.internal/re/jwt/v4#example-Parse-Hmac)
-* [Simple example of building and signing a token](https://pkg.go.dev/github.com/golang-jwt/jwt/v4#example-New-Hmac)
+* [Simple example of building and signing a token](https://pkg.go.dev/git.internal/re/jwt/v4#example-New-Hmac)
-* [Directory of Examples](https://pkg.go.dev/github.com/golang-jwt/jwt/v4#pkg-examples)
+* [Directory of Examples](https://pkg.go.dev/git.internal/re/jwt/v4#pkg-examples)
 
 ## Extensions
 
@@ -110,10 +110,10 @@ Asymmetric signing methods, such as RSA, use different keys for signing and veri
 
 Each signing method expects a different object type for its signing keys. See the package documentation for details. Here are the most common ones:
 
-* The [HMAC signing method](https://pkg.go.dev/github.com/golang-jwt/jwt/v4#SigningMethodHMAC) (`HS256`,`HS384`,`HS512`) expect `[]byte` values for signing and validation
+* The [HMAC signing method](https://pkg.go.dev/git.internal/re/jwt/v4#SigningMethodHMAC) (`HS256`,`HS384`,`HS512`) expect `[]byte` values for signing and validation
-* The [RSA signing method](https://pkg.go.dev/github.com/golang-jwt/jwt/v4#SigningMethodRSA) (`RS256`,`RS384`,`RS512`) expect `*rsa.PrivateKey` for signing and `*rsa.PublicKey` for validation
+* The [RSA signing method](https://pkg.go.dev/git.internal/re/jwt/v4#SigningMethodRSA) (`RS256`,`RS384`,`RS512`) expect `*rsa.PrivateKey` for signing and `*rsa.PublicKey` for validation
-* The [ECDSA signing method](https://pkg.go.dev/github.com/golang-jwt/jwt/v4#SigningMethodECDSA) (`ES256`,`ES384`,`ES512`) expect `*ecdsa.PrivateKey` for signing and `*ecdsa.PublicKey` for validation
+* The [ECDSA signing method](https://pkg.go.dev/git.internal/re/jwt/v4#SigningMethodECDSA) (`ES256`,`ES384`,`ES512`) expect `*ecdsa.PrivateKey` for signing and `*ecdsa.PublicKey` for validation
-* The [EdDSA signing method](https://pkg.go.dev/github.com/golang-jwt/jwt/v4#SigningMethodEd25519) (`Ed25519`) expect `ed25519.PrivateKey` for signing and `ed25519.PublicKey` for validation
+* The [EdDSA signing method](https://pkg.go.dev/git.internal/re/jwt/v4#SigningMethodEd25519) (`Ed25519`) expect `ed25519.PrivateKey` for signing and `ed25519.PublicKey` for validation
 
 ### JWT and OAuth
 
@@ -131,7 +131,7 @@ This library uses descriptive error messages whenever possible. If you are not g
 
 ## More
 
-Documentation can be found [on pkg.go.dev](https://pkg.go.dev/github.com/golang-jwt/jwt/v4).
+Documentation can be found [on pkg.go.dev](https://pkg.go.dev/git.internal/re/jwt/v4).
 
 The command line utility included in this project (cmd/jwt) provides a straightforward example of token creation and parsing as well as a useful tool for debugging your own integration. You'll also find several implementation examples in the documentation.
 

cmd/jwt/README.md

@@ -16,4 +16,4 @@ To simply display a token, use:
 
 You can install this tool with the following command:
 
-     go install github.com/golang-jwt/jwt/v4/cmd/jwt
+     go install git.internal/re/jwt/v4/cmd/jwt

cmd/jwt/main.go

@@ -17,7 +17,7 @@ import (
 	"sort"
 	"strings"
 
-	"github.com/golang-jwt/jwt/v4"
+	"git.internal/re/jwt/v4"
 )
 
 var (

ecdsa_test.go

@@ -6,7 +6,7 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/golang-jwt/jwt/v4"
+	"git.internal/re/jwt/v4"
 )
 
 var ecdsaTestData = []struct {
@@ -90,7 +90,6 @@ func TestECDSASign(t *testing.T) {
 			toSign := strings.Join(parts[0:2], ".")
 			method := jwt.GetSigningMethod(data.alg)
 			sig, err := method.Sign(toSign, ecdsaKey)
-
 			if err != nil {
 				t.Errorf("[%v] Error signing token: %v", data.name, err)
 			}

ed25519_test.go

@@ -5,7 +5,7 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/golang-jwt/jwt/v4"
+	"git.internal/re/jwt/v4"
 )
 
 var ed25519TestData = []struct {

example_test.go

@@ -5,7 +5,7 @@ import (
 	"fmt"
 	"time"
 
-	"github.com/golang-jwt/jwt/v4"
+	"git.internal/re/jwt/v4"
 )
 
 // Example (atypical) using the RegisteredClaims type by itself to parse a token.
@@ -96,7 +96,7 @@ func ExampleParseWithClaims_customClaimsType() {
 // An example of parsing the error types using bitfield checks
 func ExampleParse_errorChecking() {
 	// Token from another example.  This token is expired
-	var tokenString = "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIiLCJleHAiOjE1MDAwLCJpc3MiOiJ0ZXN0In0.HE7fK0xOQwFEr4WDgRWj4teRPZ6i3GLwD5YCm6Pwu_c"
+	tokenString := "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIiLCJleHAiOjE1MDAwLCJpc3MiOiJ0ZXN0In0.HE7fK0xOQwFEr4WDgRWj4teRPZ6i3GLwD5YCm6Pwu_c"
 
 	token, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
 		return []byte("AllYourBase"), nil

go.mod

@@ -1,4 +1,4 @@
-module github.com/golang-jwt/jwt/v4
+module git.internal/re/jwt/v4
 
 go 1.16
 

hmac_example_test.go

@@ -5,7 +5,7 @@ import (
 	"os"
 	"time"
 
-	"github.com/golang-jwt/jwt/v4"
+	"git.internal/re/jwt/v4"
 )
 
 // For HMAC signing method, the key can be any []byte. It is recommended to generate

hmac_test.go

@@ -5,7 +5,7 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/golang-jwt/jwt/v4"
+	"git.internal/re/jwt/v4"
 )
 
 var hmacTestData = []struct {

http_example_test.go

@@ -16,8 +16,8 @@ import (
 	"strings"
 	"time"
 
-	"github.com/golang-jwt/jwt/v4"
+	"git.internal/re/jwt/v4"
-	"github.com/golang-jwt/jwt/v4/request"
+	"git.internal/re/jwt/v4/request"
 )
 
 // location of the files used for signing and verification
@@ -113,7 +113,6 @@ func Example_getTokenViaHTTP() {
 }
 
 func Example_useTokenViaHTTP() {
-
 	// Make a sample token
 	// In a real world situation, this token will have been acquired from
 	// some other API call (see Example_getTokenViaHTTP)
@@ -197,7 +196,6 @@ func restrictedHandler(w http.ResponseWriter, r *http.Request) {
 		// we also only use its public counter part to verify
 		return verifyKey, nil
 	}, request.WithClaims(&CustomClaimsExample{}))
-
 	// If the token is missing or invalid, return error
 	if err != nil {
 		w.WriteHeader(http.StatusUnauthorized)

none_test.go

@@ -4,7 +4,7 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/golang-jwt/jwt/v4"
+	"git.internal/re/jwt/v4"
 )
 
 var noneTestData = []struct {

parser_test.go

@@ -10,8 +10,8 @@ import (
 	"testing"
 	"time"
 
-	"github.com/golang-jwt/jwt/v4"
+	"git.internal/re/jwt/v4"
-	"github.com/golang-jwt/jwt/v4/test"
+	"git.internal/re/jwt/v4/test"
 )
 
 var errKeyFuncError error = fmt.Errorf("error loading key")
@@ -42,7 +42,6 @@ func init() {
 	// Load private keys
 	jwtTestRSAPrivateKey = test.LoadRSAPrivateKeyFromDisk("test/sample_key")
 	jwtTestEC256PrivateKey = test.LoadECPrivateKeyFromDisk("test/ec256-private.pem")
-
 }
 
 var jwtTestData = []struct {
@@ -338,11 +337,9 @@ func signToken(claims jwt.Claims, signingMethod jwt.SigningMethod) string {
 }
 
 func TestParser_Parse(t *testing.T) {
-
 	// Iterate over test data set and run tests
 	for _, data := range jwtTestData {
 		t.Run(data.name, func(t *testing.T) {
-
 			// If the token string is blank, use helper function to generate string
 			if data.tokenString == "" {
 				data.tokenString = signToken(data.claims, data.signingMethod)
@@ -352,7 +349,7 @@ func TestParser_Parse(t *testing.T) {
 			var token *jwt.Token
 			var ve *jwt.ValidationError
 			var err error
-			var parser = data.parser
+			parser := data.parser
 			if parser == nil {
 				parser = new(jwt.Parser)
 			}
@@ -404,7 +401,7 @@ func TestParser_Parse(t *testing.T) {
 				if err == nil {
 					t.Errorf("[%v] Expecting error(s). Didn't get one.", data.name)
 				} else {
-					var all = false
+					all := false
 					for _, e := range data.err {
 						all = errors.Is(err, e)
 					}
@@ -429,7 +426,6 @@ func TestParser_Parse(t *testing.T) {
 }
 
 func TestParser_ParseUnverified(t *testing.T) {
-
 	// Iterate over test data set and run tests
 	for _, data := range jwtTestData {
 		// Skip test data, that intentionally contains malformed tokens, as they would lead to an error
@@ -446,7 +442,7 @@ func TestParser_ParseUnverified(t *testing.T) {
 			// Parse the token
 			var token *jwt.Token
 			var err error
-			var parser = data.parser
+			parser := data.parser
 			if parser == nil {
 				parser = new(jwt.Parser)
 			}
@@ -489,6 +485,7 @@ var setPaddingTestData = []struct {
 	tokenString   string
 	claims        jwt.Claims
 	paddedDecode  bool
+	strictDecode  bool
 	signingMethod jwt.SigningMethod
 	keyfunc       jwt.Keyfunc
 	valid         bool
@@ -547,19 +544,108 @@ var setPaddingTestData = []struct {
 		keyfunc:       paddedKeyFunc,
 		valid:         true,
 	},
+	// DecodeStrict tests, DecodePaddingAllowed=false
+	{
+		name: "Validated non-padded token with padding disabled, non-strict decode, non-tweaked signature",
+		tokenString: "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJwYWRkZWRiYXIifQ.bI15h-7mN0f-2diX5I4ErgNQy1uM-rJS5Sz7O0iTWtWSBxY1h6wy8Ywxe5EZTEO6GiIfk7Lk-72Ex-c5aA40QKhPwWB9BJ8O_LfKpezUVBOn0jRItDnVdsk4ccl2zsOVkbA4U4QvdrSbOYMbwoRHzDXfTFpoeMWtn3ez0aENJ8dh4E1echHp5ByI9Pu2aBsvM1WVcMt_BySweCL3f4T7jNZeXDr7Txd00yUd2gdsHYPjXorOvsgaBKN5GLsWd1zIY5z-2gCC8CRSN-IJ4NNX5ifh7l-bOXE2q7szTqa9pvyE9y6TQJhNMSE2FotRce_TOPBWgGpQ-K2I7E8x7wZ8O" +
+			"g",
+		claims:        nil,
+		paddedDecode:  false,
+		strictDecode:  false,
+		signingMethod: jwt.SigningMethodRS256,
+		keyfunc:       defaultKeyFunc,
+		valid:         true,
+	},
+	{
+		name: "Validated non-padded token with padding disabled, non-strict decode, tweaked signature",
+		tokenString: "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJwYWRkZWRiYXIifQ.bI15h-7mN0f-2diX5I4ErgNQy1uM-rJS5Sz7O0iTWtWSBxY1h6wy8Ywxe5EZTEO6GiIfk7Lk-72Ex-c5aA40QKhPwWB9BJ8O_LfKpezUVBOn0jRItDnVdsk4ccl2zsOVkbA4U4QvdrSbOYMbwoRHzDXfTFpoeMWtn3ez0aENJ8dh4E1echHp5ByI9Pu2aBsvM1WVcMt_BySweCL3f4T7jNZeXDr7Txd00yUd2gdsHYPjXorOvsgaBKN5GLsWd1zIY5z-2gCC8CRSN-IJ4NNX5ifh7l-bOXE2q7szTqa9pvyE9y6TQJhNMSE2FotRce_TOPBWgGpQ-K2I7E8x7wZ8O" +
+			"h",
+		claims:        nil,
+		paddedDecode:  false,
+		strictDecode:  false,
+		signingMethod: jwt.SigningMethodRS256,
+		keyfunc:       defaultKeyFunc,
+		valid:         true,
+	},
+	{
+		name: "Validated non-padded token with padding disabled, strict decode, non-tweaked signature",
+		tokenString: "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJwYWRkZWRiYXIifQ.bI15h-7mN0f-2diX5I4ErgNQy1uM-rJS5Sz7O0iTWtWSBxY1h6wy8Ywxe5EZTEO6GiIfk7Lk-72Ex-c5aA40QKhPwWB9BJ8O_LfKpezUVBOn0jRItDnVdsk4ccl2zsOVkbA4U4QvdrSbOYMbwoRHzDXfTFpoeMWtn3ez0aENJ8dh4E1echHp5ByI9Pu2aBsvM1WVcMt_BySweCL3f4T7jNZeXDr7Txd00yUd2gdsHYPjXorOvsgaBKN5GLsWd1zIY5z-2gCC8CRSN-IJ4NNX5ifh7l-bOXE2q7szTqa9pvyE9y6TQJhNMSE2FotRce_TOPBWgGpQ-K2I7E8x7wZ8O" +
+			"g",
+		claims:        nil,
+		paddedDecode:  false,
+		strictDecode:  true,
+		signingMethod: jwt.SigningMethodRS256,
+		keyfunc:       defaultKeyFunc,
+		valid:         true,
+	},
+	{
+		name: "Error for non-padded token with padding disabled, strict decode, tweaked signature",
+		tokenString: "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJwYWRkZWRiYXIifQ.bI15h-7mN0f-2diX5I4ErgNQy1uM-rJS5Sz7O0iTWtWSBxY1h6wy8Ywxe5EZTEO6GiIfk7Lk-72Ex-c5aA40QKhPwWB9BJ8O_LfKpezUVBOn0jRItDnVdsk4ccl2zsOVkbA4U4QvdrSbOYMbwoRHzDXfTFpoeMWtn3ez0aENJ8dh4E1echHp5ByI9Pu2aBsvM1WVcMt_BySweCL3f4T7jNZeXDr7Txd00yUd2gdsHYPjXorOvsgaBKN5GLsWd1zIY5z-2gCC8CRSN-IJ4NNX5ifh7l-bOXE2q7szTqa9pvyE9y6TQJhNMSE2FotRce_TOPBWgGpQ-K2I7E8x7wZ8O" +
+			"h",
+		claims:        nil,
+		paddedDecode:  false,
+		strictDecode:  true,
+		signingMethod: jwt.SigningMethodRS256,
+		keyfunc:       defaultKeyFunc,
+		valid:         false,
+	},
+	// DecodeStrict tests, DecodePaddingAllowed=true
+	{
+		name: "Validated padded token with padding enabled, non-strict decode, non-tweaked signature",
+		tokenString: "eyJ0eXAiOiJKV1QiLCJraWQiOiIxMjM0NTY3OC1hYmNkLTEyMzQtYWJjZC0xMjM0NTY3OGFiY2QiLCJhbGciOiJFUzI1NiIsImlzcyI6Imh0dHBzOi8vY29nbml0by1pZHAuZXUtd2VzdC0yLmFtYXpvbmF3cy5jb20vIiwiY2xpZW50IjoiN0xUY29QWnJWNDR6ZVg2WUs5VktBcHZPM3EiLCJzaWduZXIiOiJhcm46YXdzOmVsYXN0aWNsb2FkYmFsYW5jaW5nIiwiZXhwIjoxNjI5NDcwMTAxfQ==.eyJzdWIiOiIxMjM0NTY3OC1hYmNkLTEyMzQtYWJjZC0xMjM0NTY3OGFiY2QiLCJlbWFpbF92ZXJpZmllZCI6InRydWUiLCJlbWFpbCI6InVzZXJAZXhhbXBsZS5jb20iLCJ1c2VybmFtZSI6IjEyMzQ1Njc4LWFiY2QtMTIzNC1hYmNkLTEyMzQ1Njc4YWJjZCIsImV4cCI6MTYyOTQ3MDEwMSwiaXNzIjoiaHR0cHM6Ly9jb2duaXRvLWlkcC5ldS13ZXN0LTIuYW1hem9uYXdzLmNvbS8ifQ==.sx0muJ754glJvwWgkHaPrOI3L1gaPjRLLUvOQRk0WitnqC5Dtt1knorcbOzlEcH9zwPM2jYYIAYQz_qEyM3gr" +
+			"w==",
+		claims:        nil,
+		paddedDecode:  true,
+		strictDecode:  false,
+		signingMethod: jwt.SigningMethodES256,
+		keyfunc:       paddedKeyFunc,
+		valid:         true,
+	},
+	{
+		name: "Validated padded token with padding enabled, non-strict decode, tweaked signature",
+		tokenString: "eyJ0eXAiOiJKV1QiLCJraWQiOiIxMjM0NTY3OC1hYmNkLTEyMzQtYWJjZC0xMjM0NTY3OGFiY2QiLCJhbGciOiJFUzI1NiIsImlzcyI6Imh0dHBzOi8vY29nbml0by1pZHAuZXUtd2VzdC0yLmFtYXpvbmF3cy5jb20vIiwiY2xpZW50IjoiN0xUY29QWnJWNDR6ZVg2WUs5VktBcHZPM3EiLCJzaWduZXIiOiJhcm46YXdzOmVsYXN0aWNsb2FkYmFsYW5jaW5nIiwiZXhwIjoxNjI5NDcwMTAxfQ==.eyJzdWIiOiIxMjM0NTY3OC1hYmNkLTEyMzQtYWJjZC0xMjM0NTY3OGFiY2QiLCJlbWFpbF92ZXJpZmllZCI6InRydWUiLCJlbWFpbCI6InVzZXJAZXhhbXBsZS5jb20iLCJ1c2VybmFtZSI6IjEyMzQ1Njc4LWFiY2QtMTIzNC1hYmNkLTEyMzQ1Njc4YWJjZCIsImV4cCI6MTYyOTQ3MDEwMSwiaXNzIjoiaHR0cHM6Ly9jb2duaXRvLWlkcC5ldS13ZXN0LTIuYW1hem9uYXdzLmNvbS8ifQ==.sx0muJ754glJvwWgkHaPrOI3L1gaPjRLLUvOQRk0WitnqC5Dtt1knorcbOzlEcH9zwPM2jYYIAYQz_qEyM3gr" +
+			"x==",
+		claims:        nil,
+		paddedDecode:  true,
+		strictDecode:  false,
+		signingMethod: jwt.SigningMethodES256,
+		keyfunc:       paddedKeyFunc,
+		valid:         true,
+	},
+	{
+		name: "Validated padded token with padding enabled, strict decode, non-tweaked signature",
+		tokenString: "eyJ0eXAiOiJKV1QiLCJraWQiOiIxMjM0NTY3OC1hYmNkLTEyMzQtYWJjZC0xMjM0NTY3OGFiY2QiLCJhbGciOiJFUzI1NiIsImlzcyI6Imh0dHBzOi8vY29nbml0by1pZHAuZXUtd2VzdC0yLmFtYXpvbmF3cy5jb20vIiwiY2xpZW50IjoiN0xUY29QWnJWNDR6ZVg2WUs5VktBcHZPM3EiLCJzaWduZXIiOiJhcm46YXdzOmVsYXN0aWNsb2FkYmFsYW5jaW5nIiwiZXhwIjoxNjI5NDcwMTAxfQ==.eyJzdWIiOiIxMjM0NTY3OC1hYmNkLTEyMzQtYWJjZC0xMjM0NTY3OGFiY2QiLCJlbWFpbF92ZXJpZmllZCI6InRydWUiLCJlbWFpbCI6InVzZXJAZXhhbXBsZS5jb20iLCJ1c2VybmFtZSI6IjEyMzQ1Njc4LWFiY2QtMTIzNC1hYmNkLTEyMzQ1Njc4YWJjZCIsImV4cCI6MTYyOTQ3MDEwMSwiaXNzIjoiaHR0cHM6Ly9jb2duaXRvLWlkcC5ldS13ZXN0LTIuYW1hem9uYXdzLmNvbS8ifQ==.sx0muJ754glJvwWgkHaPrOI3L1gaPjRLLUvOQRk0WitnqC5Dtt1knorcbOzlEcH9zwPM2jYYIAYQz_qEyM3gr" +
+			"w==",
+		claims:        nil,
+		paddedDecode:  true,
+		strictDecode:  true,
+		signingMethod: jwt.SigningMethodES256,
+		keyfunc:       paddedKeyFunc,
+		valid:         true,
+	},
+	{
+		name: "Error for padded token with padding enabled, strict decode, tweaked signature",
+		tokenString: "eyJ0eXAiOiJKV1QiLCJraWQiOiIxMjM0NTY3OC1hYmNkLTEyMzQtYWJjZC0xMjM0NTY3OGFiY2QiLCJhbGciOiJFUzI1NiIsImlzcyI6Imh0dHBzOi8vY29nbml0by1pZHAuZXUtd2VzdC0yLmFtYXpvbmF3cy5jb20vIiwiY2xpZW50IjoiN0xUY29QWnJWNDR6ZVg2WUs5VktBcHZPM3EiLCJzaWduZXIiOiJhcm46YXdzOmVsYXN0aWNsb2FkYmFsYW5jaW5nIiwiZXhwIjoxNjI5NDcwMTAxfQ==.eyJzdWIiOiIxMjM0NTY3OC1hYmNkLTEyMzQtYWJjZC0xMjM0NTY3OGFiY2QiLCJlbWFpbF92ZXJpZmllZCI6InRydWUiLCJlbWFpbCI6InVzZXJAZXhhbXBsZS5jb20iLCJ1c2VybmFtZSI6IjEyMzQ1Njc4LWFiY2QtMTIzNC1hYmNkLTEyMzQ1Njc4YWJjZCIsImV4cCI6MTYyOTQ3MDEwMSwiaXNzIjoiaHR0cHM6Ly9jb2duaXRvLWlkcC5ldS13ZXN0LTIuYW1hem9uYXdzLmNvbS8ifQ==.sx0muJ754glJvwWgkHaPrOI3L1gaPjRLLUvOQRk0WitnqC5Dtt1knorcbOzlEcH9zwPM2jYYIAYQz_qEyM3gr" +
+			"x==",
+		claims:        nil,
+		paddedDecode:  true,
+		strictDecode:  true,
+		signingMethod: jwt.SigningMethodES256,
+		keyfunc:       paddedKeyFunc,
+		valid:         false,
+	},
 }
 
 // Extension of Parsing, this is to test out functionality specific to switching codecs with padding.
 func TestSetPadding(t *testing.T) {
 	for _, data := range setPaddingTestData {
 		t.Run(data.name, func(t *testing.T) {
+			jwt.DecodePaddingAllowed = data.paddedDecode
+			jwt.DecodeStrict = data.strictDecode
 
 			// If the token string is blank, use helper function to generate string
-			jwt.DecodePaddingAllowed = data.paddedDecode
-
 			if data.tokenString == "" {
 				data.tokenString = signToken(data.claims, data.signingMethod)
-
 			}
 
 			// Parse the token
@@ -578,15 +664,13 @@ func TestSetPadding(t *testing.T) {
 					err,
 				)
 			}
-
 		})
 		jwt.DecodePaddingAllowed = false
-
+		jwt.DecodeStrict = false
 	}
 }
 
 func BenchmarkParseUnverified(b *testing.B) {
-
 	// Iterate over test data set and run tests
 	for _, data := range jwtTestData {
 		// If the token string is blank, use helper function to generate string
@@ -595,7 +679,7 @@ func BenchmarkParseUnverified(b *testing.B) {
 		}
 
 		// Parse the token
-		var parser = data.parser
+		parser := data.parser
 		if parser == nil {
 			parser = new(jwt.Parser)
 		}

request/request.go

@@ -3,7 +3,7 @@ package request
 import (
 	"net/http"
 
-	"github.com/golang-jwt/jwt/v4"
+	"git.internal/re/jwt/v4"
 )
 
 // ParseFromRequest extracts and parses a JWT token from an HTTP request.

request/request_test.go

@@ -8,8 +8,8 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/golang-jwt/jwt/v4"
+	"git.internal/re/jwt/v4"
-	"github.com/golang-jwt/jwt/v4/test"
+	"git.internal/re/jwt/v4/test"
 )
 
 var requestTestData = []struct {

rsa_pss_test.go

@@ -10,8 +10,8 @@ import (
 	"testing"
 	"time"
 
-	"github.com/golang-jwt/jwt/v4"
+	"git.internal/re/jwt/v4"
-	"github.com/golang-jwt/jwt/v4/test"
+	"git.internal/re/jwt/v4/test"
 )
 
 var rsaPSSTestData = []struct {

rsa_test.go

@@ -5,7 +5,7 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/golang-jwt/jwt/v4"
+	"git.internal/re/jwt/v4"
 )
 
 var rsaTestData = []struct {
@@ -147,7 +147,6 @@ func TestRSAKeyParsing(t *testing.T) {
 	if k, e := jwt.ParseRSAPublicKeyFromPEM(badKey); e == nil {
 		t.Errorf("Parsed invalid key as valid private key: %v", k)
 	}
-
 }
 
 func BenchmarkRSAParsing(b *testing.B) {

test/helpers.go

@@ -5,7 +5,7 @@ import (
 	"crypto/rsa"
 	"os"
 
-	"github.com/golang-jwt/jwt/v4"
+	"git.internal/re/jwt/v4"
 )
 
 func LoadRSAPrivateKeyFromDisk(location string) *rsa.PrivateKey {

token.go

@@ -14,6 +14,12 @@ import (
 // To use the non-recommended decoding, set this boolean to `true` prior to using this package.
 var DecodePaddingAllowed bool
 
+// DecodeStrict will switch the codec used for decoding JWTs into strict mode.
+// In this mode, the decoder requires that trailing padding bits are zero, as described in RFC 4648 section 3.5.
+// Note that this is a global variable, and updating it will change the behavior on a package level, and is also NOT go-routine safe.
+// To use strict decoding, set this boolean to `true` prior to using this package.
+var DecodeStrict bool
+
 // TimeFunc provides the current time when parsing token to validate "exp" claim (expiration time).
 // You can override it to use another time value.  This is useful for testing or if your
 // server uses a different time zone than your tokens.
@@ -121,12 +127,17 @@ func EncodeSegment(seg []byte) string {
 // Deprecated: In a future release, we will demote this function to a non-exported function, since it
 // should only be used internally
 func DecodeSegment(seg string) ([]byte, error) {
+	encoding := base64.RawURLEncoding
+
 	if DecodePaddingAllowed {
 		if l := len(seg) % 4; l > 0 {
 			seg += strings.Repeat("=", 4-l)
 		}
-		return base64.URLEncoding.DecodeString(seg)
+		encoding = base64.URLEncoding
 	}
 
-	return base64.RawURLEncoding.DecodeString(seg)
+	if DecodeStrict {
+		encoding = encoding.Strict()
+	}
+	return encoding.DecodeString(seg)
 }

token_test.go

@@ -3,7 +3,7 @@ package jwt_test
 import (
 	"testing"
 
-	"github.com/golang-jwt/jwt/v4"
+	"git.internal/re/jwt/v4"
 )
 
 func TestToken_SigningString(t1 *testing.T) {

types_test.go

@@ -6,7 +6,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/golang-jwt/jwt/v4"
+	"git.internal/re/jwt/v4"
 )
 
 func TestNumericDate(t *testing.T) {
@@ -41,7 +41,6 @@ func TestSingleArrayMarshal(t *testing.T) {
 	expected := `"test"`
 
 	b, err := json.Marshal(s)
-
 	if err != nil {
 		t.Errorf("Unexpected error: %s", err)
 	}