Use fmt for error handling

claims.go

@@ -2,7 +2,7 @@ package paseto
 
 import (
 	"crypto/subtle"
-	"errors"
+	"fmt"
 	"time"
 )
 
@@ -21,10 +21,7 @@ func ForAudience(audience string) Rule {
 		}
 
 		if subtle.ConstantTimeCompare([]byte(tAud), []byte(audience)) == 0 {
-			return errors.New(
-				"this token is not intended for `" +
-					audience + "`. `" + tAud + "` found",
-			)
+			return fmt.Errorf("this token is not intended for `%s'. `%s' found", audience, tAud)
 		}
 
 		return nil
@@ -41,10 +38,7 @@ func IdentifiedBy(identifier string) Rule {
 		}
 
 		if subtle.ConstantTimeCompare([]byte(tJti), []byte(identifier)) == 0 {
-			return errors.New(
-				"this token is not identified by `" +
-					identifier + "`. `" + tJti + "` found",
-			)
+			return fmt.Errorf("this token is not identified by `%s'. `%s' found", identifier, tJti)
 		}
 
 		return nil
@@ -63,10 +57,7 @@ func IssuedBy(issuer string) Rule {
 		issBytes := []byte(issuer)
 
 		if subtle.ConstantTimeCompare(tIssBytes, issBytes) == 0 {
-			return errors.New(
-				"this token is not issued by `" +
-					issuer + "`. `" + tIss + "` found",
-			)
+			return fmt.Errorf("this token is not issued by `%s'. `%s' found", issuer, tIss)
 		}
 
 		return nil
@@ -85,7 +76,7 @@ func NotExpired() Rule {
 		}
 
 		if time.Now().After(exp) {
-			return errors.New("this token has expired")
+			return fmt.Errorf("this token has expired")
 		}
 
 		return nil
@@ -101,10 +92,7 @@ func Subject(subject string) Rule {
 		}
 
 		if subtle.ConstantTimeCompare([]byte(tSub), []byte(subject)) == 0 {
-			return errors.New(
-				"this token is not related to `" +
-					subject + "`. `" + tSub + "` found",
-			)
+			return fmt.Errorf("this token is not related to `%s'. `%s' found", subject, tSub)
 		}
 
 		return nil
@@ -121,23 +109,23 @@ func ValidAt(t time.Time) Rule {
 			return err
 		}
 		if t.Before(iat) {
-			return errors.New("the ValidAt time is before this token was issued")
+			return fmt.Errorf("the ValidAt time is before this token was issued")
 		}
 
 		nbf, err := token.GetNotBefore()
 		if err != nil {
 			return err
 		}
 		if t.Before(nbf) {
-			return errors.New("the ValidAt time is before this token's not before time")
+			return fmt.Errorf("the ValidAt time is before this token's not before time")
 		}
 
 		exp, err := token.GetExpiration()
 		if err != nil {
 			return err
 		}
 		if t.After(exp) {
-			return errors.New("the ValidAt time is after this token expires")
+			return fmt.Errorf("the ValidAt time is after this token expires")
 		}
 
 		return nil

errors.go

@@ -0,0 +1,39 @@
+package paseto
+
+import "fmt"
+
+func errorKeyLength(expected, given int) error {
+	return fmt.Errorf("key length incorrect (%d), expected %d", given, expected)
+}
+
+func errorSeedLength(expected, given int) error {
+	return fmt.Errorf("seed length incorrect (%d), expected %d", given, expected)
+}
+
+func errorMessageParts(given int) error {
+	return fmt.Errorf("invalid number of message parts in token (%d)", given)
+}
+
+func errorMessageHeader(expected Protocol, givenHeader string) error {
+	return fmt.Errorf("message header `%s' is not valid, expected `%s'", givenHeader, expected.Header())
+}
+
+func errorMessageHeaderDecrypt(expected Protocol, givenHeader string) error {
+	return fmt.Errorf("cannot decrypt message: %w", errorMessageHeader(expected, givenHeader))
+}
+
+func errorMessageHeaderVerify(expected Protocol, givenHeader string) error {
+	return fmt.Errorf("cannot verify message: %w", errorMessageHeader(expected, givenHeader))
+}
+
+var unsupportedPasetoVersion = fmt.Errorf("unsupported PASETO version")
+var unsupportedPasetoPurpose = fmt.Errorf("unsupported PASETO purpose")
+var unsupportedPayload = fmt.Errorf("unsupported payload")
+
+var errorPayloadShort = fmt.Errorf("payload is not long enough to be a valid PASETO message")
+var errorBadSignature = fmt.Errorf("bad signature")
+var errorBadMAC = fmt.Errorf("bad message authentication code")
+
+func errorDecrypt(err error) error {
+	return fmt.Errorf("the message could not be decrypted: %w", err)
+}

go.mod

@@ -3,14 +3,13 @@ module aidanwoods.dev/go-paseto
 go 1.17
 
 require (
-	github.com/pkg/errors v0.9.1
 	github.com/stretchr/testify v1.7.0
-	golang.org/x/crypto v0.0.0-20220518034528-6f7dac969898
+	golang.org/x/crypto v0.0.0-20220722155217-630584e8d5aa
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a // indirect
+	golang.org/x/sys v0.0.0-20220804214406-8e32c043e418 // indirect
 	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
 )

go.sum

@@ -1,21 +1,19 @@
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
-github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-golang.org/x/crypto v0.0.0-20220518034528-6f7dac969898 h1:SLP7Q4Di66FONjDJbCYrCRrh97focO6sLogHO7/g8F0=
-golang.org/x/crypto v0.0.0-20220518034528-6f7dac969898/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
+golang.org/x/crypto v0.0.0-20220722155217-630584e8d5aa h1:zuSxTR4o9y82ebqCUJYNGJbGPo6sKVl54f/TVDObg1c=
+golang.org/x/crypto v0.0.0-20220722155217-630584e8d5aa/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
 golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a h1:dGzPydgVsqGcTRVwiLJ1jVbufYwmzD3LfVPLKsKg+0k=
-golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220804214406-8e32c043e418 h1:9vYwv7OjYaky/tlAeD7C4oC9EsPTlaFl1H2jS++V+ME=
+golang.org/x/sys v0.0.0-20220804214406-8e32c043e418/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

message.go

@@ -4,7 +4,6 @@ import (
 	"strings"
 
 	"aidanwoods.dev/go-paseto/internal/encoding"
-	"github.com/pkg/errors"
 )
 
 // Message is a building block type, only use if you need to use Paseto
@@ -25,7 +24,7 @@ func newMessage(protocol Protocol, token string) (message, error) {
 	}
 
 	if header != protocol.Header() {
-		return message{}, errors.Errorf("Message header is not valid with the given purpose, expected %s got %s", protocol.Header(), header)
+		return message{}, errorMessageHeader(protocol, header)
 	}
 
 	payloadBytes, err := encoding.Decode(encodedPayload)
@@ -82,7 +81,7 @@ func deconstructToken(token string) (header string, encodedPayload string, encod
 
 	partsLen := len(parts)
 	if partsLen != 3 && partsLen != 4 {
-		err = errors.New("Invalid number of message parts in token")
+		err = errorMessageParts(len(parts))
 		return
 	}
 

paseto.go

@@ -1,7 +1,6 @@
 package paseto
 
 import (
-	"errors"
 	"fmt"
 )
 
@@ -53,11 +52,11 @@ type Protocol struct {
 func NewProtocol(version Version, purpose Purpose) (Protocol, error) {
 	switch version {
 	default:
-		return Protocol{}, errors.New("Unsupported PASETO version")
+		return Protocol{}, unsupportedPasetoVersion
 	case Version2:
 		switch purpose {
 		default:
-			return Protocol{}, errors.New("Unsupported PASETO purpose")
+			return Protocol{}, unsupportedPasetoPurpose
 		case Local:
 			return V2Local, nil
 		case Public:
@@ -66,7 +65,7 @@ func NewProtocol(version Version, purpose Purpose) (Protocol, error) {
 	case Version3:
 		switch purpose {
 		default:
-			return Protocol{}, errors.New("Unsupported PASETO purpose")
+			return Protocol{}, unsupportedPasetoPurpose
 		case Local:
 			return V3Local, nil
 		case Public:
@@ -75,7 +74,7 @@ func NewProtocol(version Version, purpose Purpose) (Protocol, error) {
 	case Version4:
 		switch purpose {
 		default:
-			return Protocol{}, errors.New("Unsupported PASETO purpose")
+			return Protocol{}, unsupportedPasetoPurpose
 		case Local:
 			return V4Local, nil
 		case Public:
@@ -102,11 +101,11 @@ func (p Protocol) Purpose() Purpose {
 func (p Protocol) newPayload(bytes []byte) (payload, error) {
 	switch p.version {
 	default:
-		return nil, errors.New("Unsupported PASETO version")
+		return nil, unsupportedPasetoVersion
 	case Version2:
 		switch p.purpose {
 		default:
-			return nil, errors.New("Unsupported PASETO purpose")
+			return nil, unsupportedPasetoPurpose
 		case Local:
 			return newV2LocalPayload(bytes)
 		case Public:
@@ -115,7 +114,7 @@ func (p Protocol) newPayload(bytes []byte) (payload, error) {
 	case Version3:
 		switch p.purpose {
 		default:
-			return nil, errors.New("Unsupported PASETO purpose")
+			return nil, unsupportedPasetoPurpose
 		case Local:
 			return newV3LocalPayload(bytes)
 		case Public:
@@ -124,7 +123,7 @@ func (p Protocol) newPayload(bytes []byte) (payload, error) {
 	case Version4:
 		switch p.purpose {
 		default:
-			return nil, errors.New("Unsupported PASETO purpose")
+			return nil, unsupportedPasetoPurpose
 		case Local:
 			return newV4LocalPayload(bytes)
 		case Public:
@@ -140,7 +139,7 @@ type payload interface {
 func protocolForPayload(payload payload) (Protocol, error) {
 	switch payload.(type) {
 	default:
-		return Protocol{}, errors.New("Unsupported Payload")
+		return Protocol{}, unsupportedPayload
 	case v2LocalPayload:
 		return V2Local, nil
 	case v2PublicPayload:

token.go

@@ -2,9 +2,8 @@ package paseto
 
 import (
 	"encoding/json"
+	"fmt"
 	"time"
-
-	"github.com/pkg/errors"
 )
 
 // Token is a set of paseto claims, and a footer
@@ -50,7 +49,7 @@ func NewTokenFromClaimsJSON(claimsData []byte, footer []byte) (*Token, error) {
 func (t *Token) Set(key string, value interface{}) error {
 	v, err := newTokenValue(value)
 	if err != nil {
-		return errors.Wrapf(err, "could not set key `%s`", key)
+		return fmt.Errorf("could not set key `%s': %w", key, err)
 	}
 
 	t.claims[key] = *v
@@ -63,7 +62,7 @@ func (t *Token) Set(key string, value interface{}) error {
 func (t Token) Get(key string, output interface{}) (err error) {
 	v, ok := t.claims[key]
 	if !ok {
-		return errors.Errorf("value for key `%s' not present in claims", key)
+		return fmt.Errorf("value for key `%s' not present in claims", key)
 	}
 
 	if err := json.Unmarshal(v.rawValue, &output); err != nil {

v2.go

@@ -6,7 +6,6 @@ import (
 	"aidanwoods.dev/go-paseto/internal/encoding"
 	"aidanwoods.dev/go-paseto/internal/hashing"
 	"aidanwoods.dev/go-paseto/internal/random"
-	"github.com/pkg/errors"
 	"golang.org/x/crypto/chacha20poly1305"
 )
 
@@ -31,7 +30,7 @@ func v2PublicSign(packet packet, key V2AsymmetricSecretKey) message {
 func v2PublicVerify(msg message, key V2AsymmetricPublicKey) (packet, error) {
 	payload, ok := msg.p.(v2PublicPayload)
 	if msg.header() != V2Public.Header() || !ok {
-		return packet{}, errors.Errorf("Cannot decrypt message with header: %s", msg.header())
+		return packet{}, errorMessageHeaderVerify(V2Public, msg.header())
 	}
 
 	header, footer := []byte(msg.header()), msg.footer
@@ -40,7 +39,7 @@ func v2PublicVerify(msg message, key V2AsymmetricPublicKey) (packet, error) {
 	m2 := encoding.Pae(header, data, footer)
 
 	if !ed25519.Verify(key.material, m2, payload.signature[:]) {
-		return packet{}, errors.Errorf("Bad signature")
+		return packet{}, errorBadSignature
 	}
 
 	return packet{data, footer}, nil
@@ -70,7 +69,7 @@ func v2LocalEncrypt(p packet, key V2SymmetricKey, unitTestNonce []byte) message
 func v2LocalDecrypt(msg message, key V2SymmetricKey) (packet, error) {
 	payload, ok := msg.p.(v2LocalPayload)
 	if msg.header() != V2Local.Header() || !ok {
-		return packet{}, errors.Errorf("Cannot decrypt message with header: %s", msg.header())
+		return packet{}, errorMessageHeaderDecrypt(V2Local, msg.header())
 	}
 
 	nonce, cipherText := payload.nonce, payload.cipherText
@@ -86,7 +85,7 @@ func v2LocalDecrypt(msg message, key V2SymmetricKey) (packet, error) {
 
 	plainText, err := cipher.Open(nil, nonce[:], cipherText, preAuth)
 	if err != nil {
-		return packet{}, errors.Errorf("The message could not be decrypted. %s", err)
+		return packet{}, errorDecrypt(err)
 	}
 
 	return packet{plainText, msg.footer}, nil

v2_keys.go

@@ -5,7 +5,6 @@ import (
 	"encoding/hex"
 
 	"aidanwoods.dev/go-paseto/internal/random"
-	"github.com/pkg/errors"
 )
 
 // V2AsymmetricPublicKey V2 public public key
@@ -30,7 +29,7 @@ func NewV2AsymmetricPublicKeyFromBytes(publicKey []byte) (V2AsymmetricPublicKey,
 	if len(publicKey) != 32 {
 		// even though we return error, return a random key here rather than
 		// a nil key
-		return NewV2AsymmetricSecretKey().Public(), errors.New("Key incorrect length")
+		return NewV2AsymmetricSecretKey().Public(), errorKeyLength(32, len(publicKey))
 	}
 
 	return V2AsymmetricPublicKey{publicKey}, nil
@@ -108,7 +107,7 @@ func NewV2AsymmetricSecretKeyFromBytes(privateKey []byte) (V2AsymmetricSecretKey
 	if len(privateKey) != 64 {
 		// even though we return error, return a random key here rather than
 		// a nil key
-		return NewV2AsymmetricSecretKey(), errors.New("Key incorrect length")
+		return NewV2AsymmetricSecretKey(), errorKeyLength(64, len(privateKey))
 	}
 
 	return V2AsymmetricSecretKey{privateKey}, nil
@@ -127,7 +126,7 @@ func NewV2AsymmetricSecretKeyFromSeed(hexEncoded string) (V2AsymmetricSecretKey,
 	if len(seedBytes) != 32 {
 		// even though we return error, return a random key here rather than
 		// a nil key
-		return NewV2AsymmetricSecretKey(), errors.New("Key incorrect length")
+		return NewV2AsymmetricSecretKey(), errorSeedLength(32, len(seedBytes))
 	}
 
 	return V2AsymmetricSecretKey{ed25519.NewKeyFromSeed(seedBytes)}, nil
@@ -173,7 +172,7 @@ func V2SymmetricKeyFromBytes(bytes []byte) (V2SymmetricKey, error) {
 	if len(bytes) != 32 {
 		// even though we return error, return a random key here rather than
 		// a nil key
-		return NewV2SymmetricKey(), errors.New("Key incorrect length")
+		return NewV2SymmetricKey(), errorKeyLength(32, len(bytes))
 	}
 
 	var material [32]byte