// Copyright 2020 The SwiftShader Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package util

import (
	"fmt"
	"io"

	"golang.org/x/crypto/openpgp"
)

// CheckPGP verifies that data has the PGP signature sig and was signed with the
// PGP key key.
func CheckPGP(data, sig, key io.Reader) error {
	keyring, err := openpgp.ReadArmoredKeyRing(key)
	if err != nil {
		return fmt.Errorf("Failed to read pgp key: %v", err)
	}

	if _, err := openpgp.CheckDetachedSignature(keyring, data, sig); err != nil {
		return fmt.Errorf("Failed to verify pgp: %v", err)
	}

	return nil
}