Function verifyHandshakeSignature

gmtls/auth.go:89–144

verifyHandshakeSignature verifies a signature against pre-hashed handshake contents.

(sigType uint8, pubkey crypto.PublicKey, hashFunc crypto.Hash, digest, sig []byte)

// verifyHandshakeSignature verifies a signature against pre-hashed handshake
// contents.
func verifyHandshakeSignature(sigType uint8, pubkey crypto.PublicKey, hashFunc crypto.Hash, digest, sig []byte) error {
	switch sigType {
	case signatureECDSA:
		pubKey, ok := pubkey.(*ecdsa.PublicKey)
		if !ok {
			return errors.New("tls: ECDSA signing requires a ECDSA public key")
		}
		ecdsaSig := new(ecdsaSignature)
		if _, err := asn1.Unmarshal(sig, ecdsaSig); err != nil {
			return err
		}
		if ecdsaSig.R.Sign() <= 0 || ecdsaSig.S.Sign() <= 0 {
			return errors.New("tls: ECDSA signature contained zero or negative values")
		}
		if pubKey.Curve == sm2.P256Sm2() {
			sm2Public := sm2.PublicKey{
				Curve: pubKey.Curve,
				X:     pubKey.X,
				Y:     pubKey.Y,
			}
			if !sm2Public.Verify(digest, sig) {
				return errors.New("tls: SM2 verification failure")
			}
		} else if !ecdsa.Verify(pubKey, digest, ecdsaSig.R, ecdsaSig.S) {
			return errors.New("tls: ECDSA verification failure")
		}
	case signaturePKCS1v15:
		pubKey, ok := pubkey.(*rsa.PublicKey)
		if !ok {
			return errors.New("tls: RSA signing requires a RSA public key")
		}
		if err := rsa.VerifyPKCS1v15(pubKey, hashFunc, digest, sig); err != nil {
			return err
		}
	case signatureRSAPSS:
		pubKey, ok := pubkey.(*rsa.PublicKey)
		if !ok {
			return errors.New("tls: RSA signing requires a RSA public key")
		}
		signOpts := &rsa.PSSOptions{SaltLength: rsa.PSSSaltLengthEqualsHash}
		if err := rsa.VerifyPSS(pubKey, hashFunc, digest, sig, signOpts); err != nil {
			return err
		}
	case signatureSM2:
		pubKey, ok := pubkey.(*sm2.PublicKey)
		if !ok {
			return errors.New("tls: SM2 signing requires a SM2 public key")
		}
		if ok := pubKey.Verify(digest, sig); !ok {
			return errors.New("verify sm2 signature error")
		}
	default:
		return errors.New("tls: unknown signature algorithm")
	}
	return nil
}