niki/vendor/github.com/golang-jwt/jwt/v4/rsa_pss.go

//go:build go1.4
// +build go1.4

package jwt

import (
	"crypto"
	"crypto/rand"
	"crypto/rsa"
)

// SigningMethodRSAPSS implements the RSAPSS family of signing methods signing methods

type SigningMethodRSAPSS struct {
	*SigningMethodRSA

	Options *rsa.PSSOptions

	// VerifyOptions is optional. If set overrides Options for rsa.VerifyPPS.

	// Used to accept tokens signed with rsa.PSSSaltLengthAuto, what doesn't follow

	// https://tools.ietf.org/html/rfc7518#section-3.5 but was used previously.

	// See https://github.com/dgrijalva/jwt-go/issues/285#issuecomment-437451244 for details.

	VerifyOptions *rsa.PSSOptions
}

// Specific instances for RS/PS and company.

var (
	SigningMethodPS256 *SigningMethodRSAPSS

	SigningMethodPS384 *SigningMethodRSAPSS

	SigningMethodPS512 *SigningMethodRSAPSS
)

func init() {

	// PS256

	SigningMethodPS256 = &SigningMethodRSAPSS{

		SigningMethodRSA: &SigningMethodRSA{

			Name: "PS256",

			Hash: crypto.SHA256,
		},

		Options: &rsa.PSSOptions{

			SaltLength: rsa.PSSSaltLengthEqualsHash,
		},

		VerifyOptions: &rsa.PSSOptions{

			SaltLength: rsa.PSSSaltLengthAuto,
		},
	}

	RegisterSigningMethod(SigningMethodPS256.Alg(), func() SigningMethod {

		return SigningMethodPS256

	})

	// PS384

	SigningMethodPS384 = &SigningMethodRSAPSS{

		SigningMethodRSA: &SigningMethodRSA{

			Name: "PS384",

			Hash: crypto.SHA384,
		},

		Options: &rsa.PSSOptions{

			SaltLength: rsa.PSSSaltLengthEqualsHash,
		},

		VerifyOptions: &rsa.PSSOptions{

			SaltLength: rsa.PSSSaltLengthAuto,
		},
	}

	RegisterSigningMethod(SigningMethodPS384.Alg(), func() SigningMethod {

		return SigningMethodPS384

	})

	// PS512

	SigningMethodPS512 = &SigningMethodRSAPSS{

		SigningMethodRSA: &SigningMethodRSA{

			Name: "PS512",

			Hash: crypto.SHA512,
		},

		Options: &rsa.PSSOptions{

			SaltLength: rsa.PSSSaltLengthEqualsHash,
		},

		VerifyOptions: &rsa.PSSOptions{

			SaltLength: rsa.PSSSaltLengthAuto,
		},
	}

	RegisterSigningMethod(SigningMethodPS512.Alg(), func() SigningMethod {

		return SigningMethodPS512

	})

}

// Verify implements token verification for the SigningMethod.

// For this verify method, key must be an rsa.PublicKey struct

func (m *SigningMethodRSAPSS) Verify(signingString, signature string, key interface{}) error {

	var err error

	// Decode the signature

	var sig []byte

	if sig, err = DecodeSegment(signature); err != nil {

		return err

	}

	var rsaKey *rsa.PublicKey

	switch k := key.(type) {

	case *rsa.PublicKey:

		rsaKey = k

	default:

		return ErrInvalidKey

	}

	// Create hasher

	if !m.Hash.Available() {

		return ErrHashUnavailable

	}

	hasher := m.Hash.New()

	hasher.Write([]byte(signingString))

	opts := m.Options

	if m.VerifyOptions != nil {

		opts = m.VerifyOptions

	}

	return rsa.VerifyPSS(rsaKey, m.Hash, hasher.Sum(nil), sig, opts)

}

// Sign implements token signing for the SigningMethod.

// For this signing method, key must be an rsa.PrivateKey struct

func (m *SigningMethodRSAPSS) Sign(signingString string, key interface{}) (string, error) {

	var rsaKey *rsa.PrivateKey

	switch k := key.(type) {

	case *rsa.PrivateKey:

		rsaKey = k

	default:

		return "", ErrInvalidKeyType

	}

	// Create the hasher

	if !m.Hash.Available() {

		return "", ErrHashUnavailable

	}

	hasher := m.Hash.New()

	hasher.Write([]byte(signingString))

	// Sign the string and return the encoded bytes

	if sigBytes, err := rsa.SignPSS(rand.Reader, rsaKey, m.Hash, hasher.Sum(nil), m.Options); err == nil {

		return EncodeSegment(sigBytes), nil

	} else {

		return "", err

	}

}