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// Copyright 2015 CoreOS, Inc.
//
// 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 (
"crypto/sha512"
"encoding/hex"
"fmt"
"hash"
"github.com/coreos/ignition/config/types"
)
type ErrHashMismatch struct {
Calculated string
Expected string
}
func (e ErrHashMismatch) Error() string {
return fmt.Sprintf("hash verification failed (calculated %s but expected %s)",
e.Calculated, e.Expected)
}
func AssertValid(verify types.Verification, data []byte) error {
if hash := verify.Hash; hash != nil {
hashFunc, hashSum, err := verify.HashParts()
if err != nil {
return err
}
var sum []byte
switch hashFunc {
case "sha512":
rawSum := sha512.Sum512(data)
sum = rawSum[:]
default:
return types.ErrHashUnrecognized
}
encodedSum := make([]byte, hex.EncodedLen(len(sum)))
hex.Encode(encodedSum, sum)
if string(encodedSum) != hashSum {
return ErrHashMismatch{
Calculated: string(encodedSum),
Expected: hashSum,
}
}
}
return nil
}
func GetHasher(verify types.Verification) (hash.Hash, error) {
if verify.Hash == nil {
return nil, nil
}
function, _, err := verify.HashParts()
if err != nil {
return nil, err
}
switch function {
case "sha512":
return sha512.New(), nil
default:
return nil, types.ErrHashUnrecognized
}
}
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