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Copy pathreader.go
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148 lines (127 loc) · 3.78 KB
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/*
* Minio Cloud Storage, (C) 2017 Minio, 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 hash
import (
"bytes"
"crypto/md5"
"encoding/base64"
"encoding/hex"
"errors"
"hash"
"io"
sha256 "github.com/minio/sha256-simd"
)
var errNestedReader = errors.New("Nesting of Reader detected, not allowed")
// Reader writes what it reads from an io.Reader to an MD5 and SHA256 hash.Hash.
// Reader verifies that the content of the io.Reader matches the expected checksums.
type Reader struct {
src io.Reader
size int64
md5sum, sha256sum []byte // Byte values of md5sum, sha256sum of client sent values.
md5Hash, sha256Hash hash.Hash
}
// NewReader returns a new hash Reader which computes the MD5 sum and
// SHA256 sum (if set) of the provided io.Reader at EOF.
func NewReader(src io.Reader, size int64, md5Hex, sha256Hex string) (*Reader, error) {
if _, ok := src.(*Reader); ok {
return nil, errNestedReader
}
sha256sum, err := hex.DecodeString(sha256Hex)
if err != nil {
return nil, SHA256Mismatch{}
}
md5sum, err := hex.DecodeString(md5Hex)
if err != nil {
return nil, BadDigest{}
}
var sha256Hash hash.Hash
if len(sha256sum) != 0 {
sha256Hash = sha256.New()
}
if size >= 0 {
src = io.LimitReader(src, size)
}
return &Reader{
md5sum: md5sum,
sha256sum: sha256sum,
src: src,
size: size,
md5Hash: md5.New(),
sha256Hash: sha256Hash,
}, nil
}
func (r *Reader) Read(p []byte) (n int, err error) {
n, err = r.src.Read(p)
if n > 0 {
r.md5Hash.Write(p[:n])
if r.sha256Hash != nil {
r.sha256Hash.Write(p[:n])
}
}
// At io.EOF verify if the checksums are right.
if err == io.EOF {
if cerr := r.Verify(); cerr != nil {
return 0, cerr
}
}
return
}
// Size returns the absolute number of bytes the Reader
// will return during reading. It returns -1 for unlimited
// data.
func (r *Reader) Size() int64 { return r.size }
// MD5 - returns byte md5 value
func (r *Reader) MD5() []byte {
return r.md5sum
}
// MD5Current - returns byte md5 value of the current state
// of the md5 hash after reading the incoming content.
// NOTE: Calling this function multiple times might yield
// different results if they are intermixed with Reader.
func (r *Reader) MD5Current() []byte {
return r.md5Hash.Sum(nil)
}
// SHA256 - returns byte sha256 value
func (r *Reader) SHA256() []byte {
return r.sha256sum
}
// MD5HexString returns hex md5 value.
func (r *Reader) MD5HexString() string {
return hex.EncodeToString(r.md5sum)
}
// MD5Base64String returns base64 encoded MD5sum value.
func (r *Reader) MD5Base64String() string {
return base64.StdEncoding.EncodeToString(r.md5sum)
}
// SHA256HexString returns hex sha256 value.
func (r *Reader) SHA256HexString() string {
return hex.EncodeToString(r.sha256sum)
}
// Verify verifies if the computed MD5 sum and SHA256 sum are
// equal to the ones specified when creating the Reader.
func (r *Reader) Verify() error {
if r.sha256Hash != nil && len(r.sha256sum) > 0 {
if sum := r.sha256Hash.Sum(nil); !bytes.Equal(r.sha256sum, sum) {
return SHA256Mismatch{hex.EncodeToString(r.sha256sum), hex.EncodeToString(sum)}
}
}
if len(r.md5sum) > 0 {
if sum := r.md5Hash.Sum(nil); !bytes.Equal(r.md5sum, sum) {
return BadDigest{hex.EncodeToString(r.md5sum), hex.EncodeToString(sum)}
}
}
return nil
}