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mirror of https://github.com/octoleo/restic.git synced 2024-12-22 19:08:55 +00:00

Move HashReader to backend

This commit is contained in:
Alexander Neumann 2015-02-11 19:20:45 +01:00
parent a564a454c4
commit 5f0cce8546
4 changed files with 100 additions and 86 deletions

53
backend/hashing_reader.go Normal file
View File

@ -0,0 +1,53 @@
package backend
import (
"hash"
"io"
)
type HashReader struct {
r io.Reader
h hash.Hash
sum []byte
closed bool
}
func NewHashReader(r io.Reader, h hash.Hash) *HashReader {
return &HashReader{
h: h,
r: io.TeeReader(r, h),
sum: make([]byte, 0, h.Size()),
}
}
func (h *HashReader) Read(p []byte) (n int, err error) {
if !h.closed {
n, err = h.r.Read(p)
if err == io.EOF {
h.closed = true
h.sum = h.h.Sum(h.sum)
} else if err != nil {
return
}
}
if h.closed {
// output hash
r := len(p) - n
if r > 0 {
c := copy(p[n:], h.sum)
h.sum = h.sum[c:]
n += c
err = nil
}
if len(h.sum) == 0 {
err = io.EOF
}
}
return
}

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@ -0,0 +1,46 @@
package backend_test
import (
"bytes"
"crypto/rand"
"crypto/sha256"
"io"
"testing"
"github.com/restic/restic/backend"
)
func TestHashReader(t *testing.T) {
tests := []int{5, 23, 2<<18 + 23, 1 << 20}
for _, size := range tests {
data := make([]byte, size)
_, err := io.ReadFull(rand.Reader, data)
if err != nil {
t.Fatalf("ReadFull: %v", err)
}
expectedHash := sha256.Sum256(data)
rd := backend.NewHashReader(bytes.NewReader(data), sha256.New())
target := bytes.NewBuffer(nil)
n, err := io.Copy(target, rd)
ok(t, err)
assert(t, n == int64(size)+int64(len(expectedHash)),
"HashReader: invalid number of bytes read: got %d, expected %d",
n, size+len(expectedHash))
r := target.Bytes()
resultingHash := r[len(r)-len(expectedHash):]
assert(t, bytes.Equal(expectedHash[:], resultingHash),
"HashReader: hashes do not match: expected %02x, got %02x",
expectedHash, resultingHash)
// try to read again, must return io.EOF
n2, err := rd.Read(make([]byte, 100))
assert(t, n2 == 0, "HashReader returned %d additional bytes", n)
assert(t, err == io.EOF, "HashReader returned %v instead of EOF", err)
}
}

50
key.go
View File

@ -10,7 +10,6 @@ import (
"encoding/json"
"errors"
"fmt"
"hash"
"io"
"io/ioutil"
"os"
@ -318,53 +317,6 @@ func (k *Key) Encrypt(ciphertext, plaintext []byte) (int, error) {
return k.encrypt(k.master, ciphertext, plaintext)
}
type HashReader struct {
r io.Reader
h hash.Hash
sum []byte
closed bool
}
func NewHashReader(r io.Reader, h hash.Hash) *HashReader {
return &HashReader{
h: h,
r: io.TeeReader(r, h),
sum: make([]byte, 0, h.Size()),
}
}
func (h *HashReader) Read(p []byte) (n int, err error) {
if !h.closed {
n, err = h.r.Read(p)
if err == io.EOF {
h.closed = true
h.sum = h.h.Sum(h.sum)
} else if err != nil {
return
}
}
if h.closed {
// output hash
r := len(p) - n
if r > 0 {
c := copy(p[n:], h.sum)
h.sum = h.sum[c:]
n += c
err = nil
}
if len(h.sum) == 0 {
err = io.EOF
}
}
return
}
// encryptFrom encrypts and signs data read from rd with ks. The returned
// io.Reader reads IV || Ciphertext || HMAC. For the hash function, SHA256 is
// used.
@ -389,7 +341,7 @@ func (k *Key) encryptFrom(ks *keys, rd io.Reader) io.Reader {
S: cipher.NewCTR(c, iv),
}
return NewHashReader(io.MultiReader(ivReader, encryptReader),
return backend.NewHashReader(io.MultiReader(ivReader, encryptReader),
hmac.New(sha256.New, ks.Sign))
}

View File

@ -2,7 +2,6 @@ package restic_test
import (
"bytes"
"crypto/sha256"
"flag"
"io"
"io/ioutil"
@ -234,42 +233,6 @@ func BenchmarkDecrypt(b *testing.B) {
restic.FreeChunkBuf("BenchmarkDecrypt", ciphertext)
}
func TestHashReader(t *testing.T) {
tests := []int{5, 23, 2<<18 + 23, 1 << 20}
if *testLargeCrypto {
tests = append(tests, 7<<20+123)
}
for _, size := range tests {
data := make([]byte, size)
_, err := io.ReadFull(randomReader(42, size), data)
ok(t, err)
expectedHash := sha256.Sum256(data)
rd := restic.NewHashReader(bytes.NewReader(data), sha256.New())
target := bytes.NewBuffer(nil)
n, err := io.Copy(target, rd)
ok(t, err)
assert(t, n == int64(size)+int64(len(expectedHash)),
"HashReader: invalid number of bytes read: got %d, expected %d",
n, size+len(expectedHash))
r := target.Bytes()
resultingHash := r[len(r)-len(expectedHash):]
assert(t, bytes.Equal(expectedHash[:], resultingHash),
"HashReader: hashes do not match: expected %02x, got %02x",
expectedHash, resultingHash)
// try to read again, must return io.EOF
n2, err := rd.Read(make([]byte, 100))
assert(t, n2 == 0, "HashReader returned %d additional bytes", n)
assert(t, err == io.EOF, "HashReader returned %v instead of EOF", err)
}
}
func TestEncryptStreamReader(t *testing.T) {
s := setupBackend(t)
defer teardownBackend(t, s)