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Major refactoring: Split up "cryptfs" into several internal packages

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"git status" for reference:

deleted:    cryptfs/cryptfs.go
deleted:    cryptfs/names_core.go
modified:   integration_tests/cli_test.go
modified:   integration_tests/helpers.go
renamed:    cryptfs/config_file.go -> internal/configfile/config_file.go
renamed:    cryptfs/config_test.go -> internal/configfile/config_test.go
renamed:    cryptfs/config_test/.gitignore -> internal/configfile/config_test/.gitignore
renamed:    cryptfs/config_test/PlaintextNames.conf -> internal/configfile/config_test/PlaintextNames.conf
renamed:    cryptfs/config_test/StrangeFeature.conf -> internal/configfile/config_test/StrangeFeature.conf
renamed:    cryptfs/config_test/v1.conf -> internal/configfile/config_test/v1.conf
renamed:    cryptfs/config_test/v2.conf -> internal/configfile/config_test/v2.conf
renamed:    cryptfs/kdf.go -> internal/configfile/kdf.go
renamed:    cryptfs/kdf_test.go -> internal/configfile/kdf_test.go
renamed:    cryptfs/cryptfs_content.go -> internal/contentenc/content.go
new file:   internal/contentenc/content_api.go
renamed:    cryptfs/content_test.go -> internal/contentenc/content_test.go
renamed:    cryptfs/file_header.go -> internal/contentenc/file_header.go
renamed:    cryptfs/intrablock.go -> internal/contentenc/intrablock.go
renamed:    cryptfs/address_translation.go -> internal/contentenc/offsets.go
new file:   internal/cryptocore/crypto_api.go
renamed:    cryptfs/gcm_go1.4.go -> internal/cryptocore/gcm_go1.4.go
renamed:    cryptfs/gcm_go1.5.go -> internal/cryptocore/gcm_go1.5.go
renamed:    cryptfs/nonce.go -> internal/cryptocore/nonce.go
renamed:    cryptfs/openssl_aead.go -> internal/cryptocore/openssl_aead.go
renamed:    cryptfs/openssl_benchmark.bash -> internal/cryptocore/openssl_benchmark.bash
renamed:    cryptfs/openssl_test.go -> internal/cryptocore/openssl_test.go
new file:   internal/nametransform/name_api.go
new file:   internal/nametransform/names_core.go
renamed:    cryptfs/names_diriv.go -> internal/nametransform/names_diriv.go
renamed:    cryptfs/names_noiv.go -> internal/nametransform/names_noiv.go
renamed:    cryptfs/names_test.go -> internal/nametransform/names_test.go
new file:   internal/nametransform/pad16.go
renamed:    cryptfs/log.go -> internal/toggledlog/log.go
renamed:    cryptfs/log_go1.4.go -> internal/toggledlog/log_go1.4.go
renamed:    cryptfs/log_go1.5.go -> internal/toggledlog/log_go1.5.go
modified:   main.go
modified:   masterkey.go
modified:   pathfs_frontend/file.go
modified:   pathfs_frontend/file_holes.go
modified:   pathfs_frontend/fs.go
modified:   pathfs_frontend/fs_dir.go
modified:   pathfs_frontend/names.go
modified:   test.bash
This commit is contained in:
Jakob Unterwurzacher 2016-02-06 19:20:54 +01:00
parent adcfbd79a8
commit 2b8cbd9441
43 changed files with 579 additions and 513 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

83
cryptfs/cryptfs.go
View File

@ -1,83 +0,0 @@
package cryptfs
// CryptFS is the crypto backend of GoCryptFS
import (
"crypto/aes"
"crypto/cipher"
"fmt"
)
const (
PROGRAM_NAME = "gocryptfs"
DEFAULT_PLAINBS = 4096
KEY_LEN = 32 // AES-256
AUTH_TAG_LEN = 16
DIRIV_LEN = 16 // identical to AES block size
DIRIV_FILENAME = "gocryptfs.diriv"
)
type CryptFS struct {
blockCipher cipher.Block
gcm cipher.AEAD
gcmIVLen int
gcmIVGen nonceGenerator
plainBS uint64
cipherBS uint64
// Stores an all-zero block of size cipherBS
allZeroBlock []byte
// DirIV cache for filename encryption
DirIVCache dirIVCache
}
func NewCryptFS(key []byte, useOpenssl bool, plaintextNames bool, GCMIV128 bool) *CryptFS {
if len(key) != KEY_LEN {
panic(fmt.Sprintf("Unsupported key length %d", len(key)))
}
b, err := aes.NewCipher(key)
if err != nil {
panic(err)
}
// We want the IV size in bytes
gcmIV := 96 / 8
if GCMIV128 {
gcmIV = 128 / 8
}
var gcm cipher.AEAD
if useOpenssl {
gcm = opensslGCM{key}
} else {
gcm, err = goGCMWrapper(b, gcmIV)
if err != nil {
panic(err)
}
}
plainBS := DEFAULT_PLAINBS
cipherBS := plainBS + gcmIV + AUTH_TAG_LEN
return &CryptFS{
blockCipher: b,
gcm: gcm,
gcmIVLen: gcmIV,
gcmIVGen: nonceGenerator{nonceLen: gcmIV},
plainBS: uint64(plainBS),
cipherBS: uint64(cipherBS),
allZeroBlock: make([]byte, cipherBS),
}
}
// Get plaintext block size
func (be *CryptFS) PlainBS() uint64 {
return be.plainBS
}
// Per-block storage overhead
func (be *CryptFS) BlockOverhead() uint64 {
return be.cipherBS - be.plainBS
}

134
cryptfs/names_core.go
View File

@ -1,134 +0,0 @@
package cryptfs
// Filename encryption / decryption functions
import (
"crypto/aes"
"crypto/cipher"
"encoding/base64"
"errors"
"fmt"
"github.com/rfjakob/eme"
)
// DecryptName - decrypt base64-encoded encrypted filename "cipherName"
// The used encryption is either CBC or EME, depending on the "EMENames" argument.
//
// This function is exported because it allows for a very efficient readdir
// implementation (read IV once, decrypt all names using this function).
func (be *CryptFS) DecryptName(cipherName string, iv []byte, EMENames bool) (string, error) {
return be.decryptName(cipherName, iv, EMENames)
}
// decryptName - decrypt base64-encoded encrypted filename "cipherName".
// The used encryption is either CBC or EME, depending on the "EMENames" argument.
func (be *CryptFS) decryptName(cipherName string, iv []byte, EMENames bool) (string, error) {
// Make sure relative symlinks still work after encryption
// by passing these through unchanged
if cipherName == "." || cipherName == ".." {
return cipherName, nil
}
bin, err := base64.URLEncoding.DecodeString(cipherName)
if err != nil {
return "", err
}
if len(bin)%aes.BlockSize != 0 {
return "", fmt.Errorf("Decoded length %d is not a multiple of the AES block size", len(bin))
}
if EMENames {
bin = eme.Transform(be.blockCipher, iv, bin, eme.DirectionDecrypt)
} else {
cbc := cipher.NewCBCDecrypter(be.blockCipher, iv)
cbc.CryptBlocks(bin, bin)
}
bin, err = be.unPad16(bin)
if err != nil {
return "", err
}
plain := string(bin)
return plain, err
}
// encryptName - encrypt "plainName", return base64-encoded "cipherName64"
// The used encryption is either CBC or EME, depending on the "EMENames" argument.
func (be *CryptFS) encryptName(plainName string, iv []byte, EMENames bool) (cipherName64 string) {
// Make sure relative symlinks still work after encryption
// by passing these trough unchanged
if plainName == "." || plainName == ".." {
return plainName
}
bin := []byte(plainName)
bin = be.pad16(bin)
if EMENames {
bin = eme.Transform(be.blockCipher, iv, bin, eme.DirectionEncrypt)
} else {
cbc := cipher.NewCBCEncrypter(be.blockCipher, iv)
cbc.CryptBlocks(bin, bin)
}
cipherName64 = base64.URLEncoding.EncodeToString(bin)
return cipherName64
}
// pad16 - pad filename to 16 byte blocks using standard PKCS#7 padding
// https://tools.ietf.org/html/rfc5652#section-6.3
func (be *CryptFS) pad16(orig []byte) (padded []byte) {
oldLen := len(orig)
if oldLen == 0 {
panic("Padding zero-length string makes no sense")
}
padLen := aes.BlockSize - oldLen%aes.BlockSize
if padLen == 0 {
padLen = aes.BlockSize
}
newLen := oldLen + padLen
padded = make([]byte, newLen)
copy(padded, orig)
padByte := byte(padLen)
for i := oldLen; i < newLen; i++ {
padded[i] = padByte
}
return padded
}
// unPad16 - remove padding
func (be *CryptFS) unPad16(orig []byte) ([]byte, error) {
oldLen := len(orig)
if oldLen%aes.BlockSize != 0 {
return nil, errors.New("Unaligned size")
}
// The last byte is always a padding byte
padByte := orig[oldLen-1]
// The padding byte's value is the padding length
padLen := int(padByte)
// Padding must be at least 1 byte
if padLen <= 0 {
return nil, errors.New("Padding cannot be zero-length")
}
// Larger paddings make no sense
if padLen > aes.BlockSize {
return nil, errors.New("Padding cannot be larger than 16")
}
// All padding bytes must be identical
for i := oldLen - padLen; i < oldLen; i++ {
if orig[i] != padByte {
return nil, errors.New(fmt.Sprintf("Padding byte at i=%d is invalid", i))
}
}
newLen := oldLen - padLen
// Padding an empty string makes no sense
if newLen == 0 {
return nil, errors.New("Unpadded length is zero")
}
return orig[0:newLen], nil
}

15
integration_tests/cli_test.go
View File

@ -7,7 +7,8 @@ import (
"os/exec"
"testing"
"github.com/rfjakob/gocryptfs/cryptfs"
"github.com/rfjakob/gocryptfs/internal/configfile"
"github.com/rfjakob/gocryptfs/internal/nametransform"
)
// Test -init flag
@ -26,7 +27,7 @@ func TestInit(t *testing.T) {
if err != nil {
t.Fatal(err)
}
_, err = os.Stat(dir + cryptfs.ConfDefaultName)
_, err = os.Stat(dir + configfile.ConfDefaultName)
if err != nil {
t.Fatal(err)
}
@ -96,22 +97,22 @@ func TestInitPlaintextNames(t *testing.T) {
if err != nil {
t.Fatal(err)
}
_, err = os.Stat(dir + cryptfs.ConfDefaultName)
_, err = os.Stat(dir + configfile.ConfDefaultName)
if err != nil {
t.Fatal(err)
}
_, err = os.Stat(dir + cryptfs.DIRIV_FILENAME)
_, err = os.Stat(dir + nametransform.DirIVFilename)
if err == nil {
t.Errorf("gocryptfs.diriv should not have been created with -plaintextnames")
}
_, cf, err := cryptfs.LoadConfFile(dir+cryptfs.ConfDefaultName, "test")
_, cf, err := configfile.LoadConfFile(dir+configfile.ConfDefaultName, "test")
if err != nil {
t.Fatal(err)
}
if !cf.IsFeatureFlagSet(cryptfs.FlagPlaintextNames) {
if !cf.IsFeatureFlagSet(configfile.FlagPlaintextNames) {
t.Error("PlaintextNames flag should be set but isnt")
}
if cf.IsFeatureFlagSet(cryptfs.FlagEMENames) || cf.IsFeatureFlagSet(cryptfs.FlagDirIV) {
if cf.IsFeatureFlagSet(configfile.FlagEMENames) || cf.IsFeatureFlagSet(configfile.FlagDirIV) {
t.Error("FlagEMENames and FlagDirIV should be not set")
}
}

6
integration_tests/helpers.go
View File

@ -10,7 +10,7 @@ import (
"syscall"
"testing"
"github.com/rfjakob/gocryptfs/cryptfs"
"github.com/rfjakob/gocryptfs/internal/nametransform"
)
// Note: the code assumes that all have a trailing slash
@ -42,7 +42,7 @@ func resetTmpDir() {
fmt.Println(err)
os.Exit(1)
}
err = cryptfs.WriteDirIV(defaultCipherDir)
err = nametransform.WriteDirIV(defaultCipherDir)
if err != nil {
fmt.Println(err)
os.Exit(1)
@ -58,9 +58,9 @@ func mount(c string, p string, extraArgs ...string) {
args = append(args, c)
args = append(args, p)
cmd := exec.Command(gocryptfsBinary, args...)
cmd.Stderr = os.Stderr
if testing.Verbose() {
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
}
err := cmd.Run()
if err != nil {

29
cryptfs/config_file.go → internal/configfile/config_file.go
View File

@ -1,10 +1,14 @@
package cryptfs
package configfile
import (
"encoding/json"
"fmt"
"io/ioutil"
"log"
"github.com/rfjakob/gocryptfs/internal/cryptocore"
"github.com/rfjakob/gocryptfs/internal/contentenc"
"github.com/rfjakob/gocryptfs/internal/toggledlog"
)
import "os"
@ -36,10 +40,10 @@ type ConfFile struct {
func CreateConfFile(filename string, password string, plaintextNames bool, logN int) error {
var cf ConfFile
cf.filename = filename
cf.Version = HEADER_CURRENT_VERSION
cf.Version = contentenc.CurrentVersion
// Generate new random master key
key := RandBytes(KEY_LEN)
key := cryptocore.RandBytes(cryptocore.KeyLen)
// Encrypt it using the password
// This sets ScryptObject and EncryptedKey
@ -75,11 +79,11 @@ func LoadConfFile(filename string, password string) ([]byte, *ConfFile, error) {
// Unmarshal
err = json.Unmarshal(js, &cf)
if err != nil {
Warn.Printf("Failed to unmarshal config file")
toggledlog.Warn.Printf("Failed to unmarshal config file")
return nil, nil, err
}
if cf.Version != HEADER_CURRENT_VERSION {
if cf.Version != contentenc.CurrentVersion {
return nil, nil, fmt.Errorf("Unsupported on-disk format %d", cf.Version)
}
@ -95,11 +99,13 @@ func LoadConfFile(filename string, password string) ([]byte, *ConfFile, error) {
// Unlock master key using password-based key
// We use stock go GCM instead of OpenSSL here as speed is not important
// and we get better error messages
cfs := NewCryptFS(scryptHash, false, false, false)
key, err := cfs.DecryptBlock(cf.EncryptedKey, 0, nil)
cc := cryptocore.New(scryptHash, false, false)
ce := contentenc.New(cc, 4096)
key, err := ce.DecryptBlock(cf.EncryptedKey, 0, nil)
if err != nil {
Warn.Printf("failed to unlock master key: %s", err.Error())
Warn.Printf("Password incorrect.")
toggledlog.Warn.Printf("failed to unlock master key: %s", err.Error())
toggledlog.Warn.Printf("Password incorrect.")
return nil, nil, err
}
@ -116,8 +122,9 @@ func (cf *ConfFile) EncryptKey(key []byte, password string, logN int) {
scryptHash := cf.ScryptObject.DeriveKey(password)
// Lock master key using password-based key
cfs := NewCryptFS(scryptHash, false, false, false)
cf.EncryptedKey = cfs.EncryptBlock(key, 0, nil)
cc := cryptocore.New(scryptHash, false, false)
ce := contentenc.New(cc, 4096)
cf.EncryptedKey = ce.EncryptBlock(key, 0, nil)
}
// WriteFile - write out config in JSON format to file "filename.tmp"

2
cryptfs/config_test.go → internal/configfile/config_test.go
View File

@ -1,4 +1,4 @@
package cryptfs
package configfile
import (
"fmt"

0
cryptfs/config_test/.gitignore → internal/configfile/config_test/.gitignore vendored
View File

0
cryptfs/config_test/PlaintextNames.conf → internal/configfile/config_test/PlaintextNames.conf
View File

0
cryptfs/config_test/StrangeFeature.conf → internal/configfile/config_test/StrangeFeature.conf
View File

0
cryptfs/config_test/v1.conf → internal/configfile/config_test/v1.conf
View File

0
cryptfs/config_test/v2.conf → internal/configfile/config_test/v2.conf
View File

15
cryptfs/kdf.go → internal/configfile/kdf.go
View File

@ -1,16 +1,19 @@
package cryptfs
package configfile
import (
"fmt"
"golang.org/x/crypto/scrypt"
"math"
"os"
"golang.org/x/crypto/scrypt"
"github.com/rfjakob/gocryptfs/internal/cryptocore"
)
const (
// 1 << 16 uses 64MB of memory,
// takes 4 seconds on my Atom Z3735F netbook
SCRYPT_DEFAULT_LOGN = 16
ScryptDefaultLogN = 16
)
type scryptKdf struct {
@ -23,9 +26,9 @@ type scryptKdf struct {
func NewScryptKdf(logN int) scryptKdf {
var s scryptKdf
s.Salt = RandBytes(KEY_LEN)
s.Salt = cryptocore.RandBytes(cryptocore.KeyLen)
if logN <= 0 {
s.N = 1 << SCRYPT_DEFAULT_LOGN
s.N = 1 << ScryptDefaultLogN
} else {
if logN < 10 {
fmt.Println("Error: scryptn below 10 is too low to make sense. Aborting.")
@ -35,7 +38,7 @@ func NewScryptKdf(logN int) scryptKdf {
}
s.R = 8 // Always 8
s.P = 1 // Always 1
s.KeyLen = KEY_LEN
s.KeyLen = cryptocore.KeyLen
return s
}

2
cryptfs/kdf_test.go → internal/configfile/kdf_test.go
View File

@ -1,4 +1,4 @@
package cryptfs
package configfile
import (
"testing"

49
cryptfs/cryptfs_content.go → internal/contentenc/content.go
View File

@ -1,31 +1,18 @@
package cryptfs
package contentenc
// File content encryption / decryption
import (
"bytes"
"crypto/cipher"
"crypto/md5"
"encoding/binary"
"bytes"
"encoding/hex"
"errors"
"os"
"github.com/rfjakob/gocryptfs/internal/toggledlog"
)
// md5sum - debug helper, return md5 hex string
func md5sum(buf []byte) string {
rawHash := md5.Sum(buf)
hash := hex.EncodeToString(rawHash[:])
return hash
}
type CryptFile struct {
file *os.File
gcm cipher.AEAD
}
// DecryptBlocks - Decrypt a number of blocks
func (be *CryptFS) DecryptBlocks(ciphertext []byte, firstBlockNo uint64, fileId []byte) ([]byte, error) {
func (be *ContentEnc) DecryptBlocks(ciphertext []byte, firstBlockNo uint64, fileId []byte) ([]byte, error) {
cBuf := bytes.NewBuffer(ciphertext)
var err error
var pBuf bytes.Buffer
@ -46,7 +33,7 @@ func (be *CryptFS) DecryptBlocks(ciphertext []byte, firstBlockNo uint64, fileId
//
// Corner case: A full-sized block of all-zero ciphertext bytes is translated
// to an all-zero plaintext block, i.e. file hole passtrough.
func (be *CryptFS) DecryptBlock(ciphertext []byte, blockNo uint64, fileId []byte) ([]byte, error) {
func (be *ContentEnc) DecryptBlock(ciphertext []byte, blockNo uint64, fileId []byte) ([]byte, error) {
// Empty block?
if len(ciphertext) == 0 {
@ -55,30 +42,30 @@ func (be *CryptFS) DecryptBlock(ciphertext []byte, blockNo uint64, fileId []byte
// All-zero block?
if bytes.Equal(ciphertext, be.allZeroBlock) {
Debug.Printf("DecryptBlock: file hole encountered")
toggledlog.Debug.Printf("DecryptBlock: file hole encountered")
return make([]byte, be.plainBS), nil
}
if len(ciphertext) < be.gcmIVLen {
Warn.Printf("DecryptBlock: Block is too short: %d bytes", len(ciphertext))
if len(ciphertext) < be.cryptoCore.IVLen {
toggledlog.Warn.Printf("DecryptBlock: Block is too short: %d bytes", len(ciphertext))
return nil, errors.New("Block is too short")
}
// Extract nonce
nonce := ciphertext[:be.gcmIVLen]
nonce := ciphertext[:be.cryptoCore.IVLen]
ciphertextOrig := ciphertext
ciphertext = ciphertext[be.gcmIVLen:]
ciphertext = ciphertext[be.cryptoCore.IVLen:]
// Decrypt
var plaintext []byte
aData := make([]byte, 8)
aData = append(aData, fileId...)
binary.BigEndian.PutUint64(aData, blockNo)
plaintext, err := be.gcm.Open(plaintext, nonce, ciphertext, aData)
plaintext, err := be.cryptoCore.Gcm.Open(plaintext, nonce, ciphertext, aData)
if err != nil {
Warn.Printf("DecryptBlock: %s, len=%d, md5=%s", err.Error(), len(ciphertextOrig), md5sum(ciphertextOrig))
Debug.Println(hex.Dump(ciphertextOrig))
toggledlog.Warn.Printf("DecryptBlock: %s, len=%d", err.Error(), len(ciphertextOrig))
toggledlog.Debug.Println(hex.Dump(ciphertextOrig))
return nil, err
}
@ -86,7 +73,7 @@ func (be *CryptFS) DecryptBlock(ciphertext []byte, blockNo uint64, fileId []byte
}
// encryptBlock - Encrypt and add IV and MAC
func (be *CryptFS) EncryptBlock(plaintext []byte, blockNo uint64, fileID []byte) []byte {
func (be *ContentEnc) EncryptBlock(plaintext []byte, blockNo uint64, fileID []byte) []byte {
// Empty block?
if len(plaintext) == 0 {
@ -94,7 +81,7 @@ func (be *CryptFS) EncryptBlock(plaintext []byte, blockNo uint64, fileID []byte)
}
// Get fresh nonce
nonce := be.gcmIVGen.Get()
nonce := be.cryptoCore.GcmIVGen.Get()
// Authenticate block with block number and file ID
aData := make([]byte, 8)
@ -102,14 +89,14 @@ func (be *CryptFS) EncryptBlock(plaintext []byte, blockNo uint64, fileID []byte)
aData = append(aData, fileID...)
// Encrypt plaintext and append to nonce
ciphertext := be.gcm.Seal(nonce, nonce, plaintext, aData)
ciphertext := be.cryptoCore.Gcm.Seal(nonce, nonce, plaintext, aData)
return ciphertext
}
// MergeBlocks - Merge newData into oldData at offset
// New block may be bigger than both newData and oldData
func (be *CryptFS) MergeBlocks(oldData []byte, newData []byte, offset int) []byte {
func (be *ContentEnc) MergeBlocks(oldData []byte, newData []byte, offset int) []byte {
// Make block of maximum size
out := make([]byte, be.plainBS)

31
internal/contentenc/content_api.go Normal file
View File

@ -0,0 +1,31 @@
package contentenc
import "github.com/rfjakob/gocryptfs/internal/cryptocore"
type ContentEnc struct {
// Cryptographic primitives
cryptoCore *cryptocore.CryptoCore
// Plaintext block size
plainBS uint64
// Ciphertext block size
cipherBS uint64
// All-zero block of size cipherBS, for fast compares
allZeroBlock []byte
}
func New(cc *cryptocore.CryptoCore, plainBS uint64) *ContentEnc {
cipherBS := plainBS + uint64(cc.IVLen) + cryptocore.AuthTagLen
return &ContentEnc{
cryptoCore: cc,
plainBS: plainBS,
cipherBS: cipherBS,
allZeroBlock: make([]byte, cipherBS),
}
}
func (be *ContentEnc) PlainBS() uint64 {
return be.plainBS
}

2
cryptfs/content_test.go → internal/contentenc/content_test.go
View File

@ -1,4 +1,4 @@
package cryptfs
package contentenc
import (
"testing"

18
cryptfs/file_header.go → internal/contentenc/file_header.go
View File

@ -1,4 +1,4 @@
package cryptfs
package contentenc
// Per-file header
//
@ -7,10 +7,14 @@ package cryptfs
import (
"encoding/binary"
"fmt"
"github.com/rfjakob/gocryptfs/internal/cryptocore"
)
const (
HEADER_CURRENT_VERSION = 2 // Current on-disk-format version
// Current On-Disk-Format version
CurrentVersion = 2
HEADER_VERSION_LEN = 2 // uint16
HEADER_ID_LEN = 16 // 128 bit random file id
HEADER_LEN = HEADER_VERSION_LEN + HEADER_ID_LEN // Total header length
@ -23,7 +27,7 @@ type FileHeader struct {
// Pack - serialize fileHeader object
func (h *FileHeader) Pack() []byte {
if len(h.Id) != HEADER_ID_LEN || h.Version != HEADER_CURRENT_VERSION {
if len(h.Id) != HEADER_ID_LEN || h.Version != CurrentVersion {
panic("FileHeader object not properly initialized")
}
buf := make([]byte, HEADER_LEN)
@ -40,8 +44,8 @@ func ParseHeader(buf []byte) (*FileHeader, error) {
}
var h FileHeader
h.Version = binary.BigEndian.Uint16(buf[0:HEADER_VERSION_LEN])
if h.Version != HEADER_CURRENT_VERSION {
return nil, fmt.Errorf("ParseHeader: invalid version: got %d, want %d", h.Version, HEADER_CURRENT_VERSION)
if h.Version != CurrentVersion {
return nil, fmt.Errorf("ParseHeader: invalid version: got %d, want %d", h.Version, CurrentVersion)
}
h.Id = buf[HEADER_VERSION_LEN:]
return &h, nil
@ -50,7 +54,7 @@ func ParseHeader(buf []byte) (*FileHeader, error) {
// RandomHeader - create new fileHeader object with random Id
func RandomHeader() *FileHeader {
var h FileHeader
h.Version = HEADER_CURRENT_VERSION
h.Id = RandBytes(HEADER_ID_LEN)
h.Version = CurrentVersion
h.Id = cryptocore.RandBytes(HEADER_ID_LEN)
return &h
}

4
cryptfs/intrablock.go → internal/contentenc/intrablock.go
View File

@ -1,11 +1,11 @@
package cryptfs
package contentenc
// intraBlock identifies a part of a file block
type intraBlock struct {
BlockNo uint64 // Block number in file
Skip uint64 // Offset into block plaintext
Length uint64 // Length of data from this block
fs *CryptFS
fs *ContentEnc
}
// isPartial - is the block partial? This means we have to do read-modify-write.

30
cryptfs/address_translation.go → internal/contentenc/offsets.go
View File

@ -1,29 +1,33 @@
package cryptfs
package contentenc
// CryptFS methods that translate offsets between ciphertext and plaintext
import (
"github.com/rfjakob/gocryptfs/internal/toggledlog"
)
// Contentenc methods that translate offsets between ciphertext and plaintext
// get the block number at plain-text offset
func (be *CryptFS) PlainOffToBlockNo(plainOffset uint64) uint64 {
func (be *ContentEnc) PlainOffToBlockNo(plainOffset uint64) uint64 {
return plainOffset / be.plainBS
}
// get the block number at ciphter-text offset
func (be *CryptFS) CipherOffToBlockNo(cipherOffset uint64) uint64 {
func (be *ContentEnc) CipherOffToBlockNo(cipherOffset uint64) uint64 {
return (cipherOffset - HEADER_LEN) / be.cipherBS
}
// get ciphertext offset of block "blockNo"
func (be *CryptFS) BlockNoToCipherOff(blockNo uint64) uint64 {
func (be *ContentEnc) BlockNoToCipherOff(blockNo uint64) uint64 {
return HEADER_LEN + blockNo*be.cipherBS
}
// get plaintext offset of block "blockNo"
func (be *CryptFS) BlockNoToPlainOff(blockNo uint64) uint64 {
func (be *ContentEnc) BlockNoToPlainOff(blockNo uint64) uint64 {
return blockNo * be.plainBS
}
// PlainSize - calculate plaintext size from ciphertext size
func (be *CryptFS) CipherSizeToPlainSize(cipherSize uint64) uint64 {
func (be *ContentEnc) CipherSizeToPlainSize(cipherSize uint64) uint64 {
// Zero sized files stay zero-sized
if cipherSize == 0 {
@ -31,12 +35,12 @@ func (be *CryptFS) CipherSizeToPlainSize(cipherSize uint64) uint64 {
}
if cipherSize == HEADER_LEN {
Warn.Printf("cipherSize %d == header size: interrupted write?\n", cipherSize)
toggledlog.Warn.Printf("cipherSize %d == header size: interrupted write?\n", cipherSize)
return 0
}
if cipherSize < HEADER_LEN {
Warn.Printf("cipherSize %d < header size: corrupt file\n", cipherSize)
toggledlog.Warn.Printf("cipherSize %d < header size: corrupt file\n", cipherSize)
return 0
}
@ -50,7 +54,7 @@ func (be *CryptFS) CipherSizeToPlainSize(cipherSize uint64) uint64 {
}
// CipherSize - calculate ciphertext size from plaintext size
func (be *CryptFS) PlainSizeToCipherSize(plainSize uint64) uint64 {
func (be *ContentEnc) PlainSizeToCipherSize(plainSize uint64) uint64 {
// Block number at last byte
blockNo := be.PlainOffToBlockNo(plainSize - 1)
@ -62,7 +66,7 @@ func (be *CryptFS) PlainSizeToCipherSize(plainSize uint64) uint64 {
}
// Split a plaintext byte range into (possibly partial) blocks
func (be *CryptFS) ExplodePlainRange(offset uint64, length uint64) []intraBlock {
func (be *ContentEnc) ExplodePlainRange(offset uint64, length uint64) []intraBlock {
var blocks []intraBlock
var nextBlock intraBlock
nextBlock.fs = be
@ -81,6 +85,10 @@ func (be *CryptFS) ExplodePlainRange(offset uint64, length uint64) []intraBlock
return blocks
}
func (be *ContentEnc) BlockOverhead() uint64 {
return be.cipherBS - be.plainBS
}
func MinUint64(x uint64, y uint64) uint64 {
if x < y {
return x

56
internal/cryptocore/crypto_api.go Normal file
View File

@ -0,0 +1,56 @@
package cryptocore
import (
"crypto/cipher"
"crypto/aes"
"fmt"
)
const (
KeyLen = 32 // AES-256
AuthTagLen = 16
)
type CryptoCore struct {
BlockCipher cipher.Block
Gcm cipher.AEAD
GcmIVGen *nonceGenerator
IVLen int
}
func New(key []byte, useOpenssl bool, GCMIV128 bool) *CryptoCore {
if len(key) != KeyLen {
panic(fmt.Sprintf("Unsupported key length %d", len(key)))
}
// We want the IV size in bytes
IVLen := 96 / 8
if GCMIV128 {
IVLen = 128 / 8
}
// We always use built-in Go crypto for blockCipher because it is not
// performance-critical.
blockCipher, err := aes.NewCipher(key)
if err != nil {
panic(err)
}
var gcm cipher.AEAD
if useOpenssl {
gcm = opensslGCM{key}
} else {
gcm, err = goGCMWrapper(blockCipher, IVLen)
if err != nil {
panic(err)
}
}
return &CryptoCore{
BlockCipher: blockCipher,
Gcm: gcm,
GcmIVGen: &nonceGenerator{nonceLen: IVLen},
IVLen: IVLen,
}
}

2
cryptfs/gcm_go1.4.go → internal/cryptocore/gcm_go1.4.go
View File

@ -1,7 +1,7 @@
// +build !go1.5
// = go 1.4 or lower
package cryptfs
package cryptocore
import (
"crypto/cipher"

2
cryptfs/gcm_go1.5.go → internal/cryptocore/gcm_go1.5.go
View File

@ -1,7 +1,7 @@
// +build go1.5
// = go 1.5 or higher
package cryptfs
package cryptocore
import (
"crypto/cipher"

8
cryptfs/nonce.go → internal/cryptocore/nonce.go
View File

@ -1,4 +1,4 @@
package cryptfs
package cryptocore
import (
"bytes"
@ -6,6 +6,8 @@ import (
"encoding/binary"
"encoding/hex"
"fmt"
"github.com/rfjakob/gocryptfs/internal/toggledlog"
)
// Get "n" random bytes from /dev/urandom or panic
@ -29,10 +31,10 @@ type nonceGenerator struct {
nonceLen int // bytes
}
// Get a random 96 bit nonce
// Get a random "nonceLen"-byte nonce
func (n *nonceGenerator) Get() []byte {
nonce := RandBytes(n.nonceLen)
Debug.Printf("nonceGenerator.Get(): %s\n", hex.EncodeToString(nonce))
toggledlog.Debug.Printf("nonceGenerator.Get(): %s\n", hex.EncodeToString(nonce))
if bytes.Equal(nonce, n.lastNonce) {
m := fmt.Sprintf("Got the same nonce twice: %s. This should never happen!", hex.EncodeToString(nonce))
panic(m)

14
cryptfs/openssl_aead.go → internal/cryptocore/openssl_aead.go
View File

@ -1,4 +1,4 @@
package cryptfs
package cryptocore
// Implements cipher.AEAD with OpenSSL backend
@ -13,7 +13,7 @@ type opensslGCM struct {
}
func (be opensslGCM) Overhead() int {
return AUTH_TAG_LEN
return AuthTagLen
}
func (be opensslGCM) NonceSize() int {
@ -28,11 +28,11 @@ func (be opensslGCM) Seal(dst, nonce, plaintext, data []byte) []byte {
// Preallocate output buffer
var cipherBuf bytes.Buffer
cipherBuf.Grow(len(dst) + len(plaintext) + AUTH_TAG_LEN)
cipherBuf.Grow(len(dst) + len(plaintext) + AuthTagLen)
// Output will be appended to dst
cipherBuf.Write(dst)
ectx, err := openssl.NewGCMEncryptionCipherCtx(KEY_LEN*8, nil, be.key, nonce)
ectx, err := openssl.NewGCMEncryptionCipherCtx(KeyLen*8, nil, be.key, nonce)
if err != nil {
panic(err)
}
@ -69,11 +69,11 @@ func (be opensslGCM) Seal(dst, nonce, plaintext, data []byte) []byte {
func (be opensslGCM) Open(dst, nonce, ciphertext, data []byte) ([]byte, error) {
l := len(ciphertext)
tag := ciphertext[l-AUTH_TAG_LEN : l]
ciphertext = ciphertext[0 : l-AUTH_TAG_LEN]
tag := ciphertext[l-AuthTagLen : l]
ciphertext = ciphertext[0 : l-AuthTagLen]
plainBuf := bytes.NewBuffer(dst)
dctx, err := openssl.NewGCMDecryptionCipherCtx(KEY_LEN*8, nil, be.key, nonce)
dctx, err := openssl.NewGCMDecryptionCipherCtx(KeyLen*8, nil, be.key, nonce)
if err != nil {
return nil, err
}

0
cryptfs/openssl_benchmark.bash → internal/cryptocore/openssl_benchmark.bash
View File

2
cryptfs/openssl_test.go → internal/cryptocore/openssl_test.go
View File

@ -1,4 +1,4 @@
package cryptfs
package cryptocore
// Benchmark go built-int GCM against spacemonkey openssl bindings
//

16
internal/nametransform/name_api.go Normal file
View File

@ -0,0 +1,16 @@
package nametransform
import "github.com/rfjakob/gocryptfs/internal/cryptocore"
type NameTransform struct {
cryptoCore *cryptocore.CryptoCore
useEME bool
DirIVCache dirIVCache
}
func New(c *cryptocore.CryptoCore, useEME bool) *NameTransform {
return &NameTransform{
cryptoCore: c,
useEME: useEME,
}
}

63
internal/nametransform/names_core.go Normal file
View File

@ -0,0 +1,63 @@
package nametransform
// Filename encryption / decryption functions
import (
"crypto/aes"
"crypto/cipher"
"encoding/base64"
"fmt"
"github.com/rfjakob/eme"
)
// DecryptName - decrypt base64-encoded encrypted filename "cipherName"
// The used encryption is either CBC or EME, depending on "useEME".
//
// This function is exported because it allows for a very efficient readdir
// implementation (read IV once, decrypt all names using this function).
func (n *NameTransform) DecryptName(cipherName string, iv []byte) (string, error) {
bin, err := base64.URLEncoding.DecodeString(cipherName)
if err != nil {
return "", err
}
if len(bin)%aes.BlockSize != 0 {
return "", fmt.Errorf("Decoded length %d is not a multiple of the AES block size", len(bin))
}
if n.useEME {
bin = eme.Transform(n.cryptoCore.BlockCipher, iv, bin, eme.DirectionDecrypt)
} else {
cbc := cipher.NewCBCDecrypter(n.cryptoCore.BlockCipher, iv)
cbc.CryptBlocks(bin, bin)
}
bin, err = unPad16(bin)
if err != nil {
return "", err
}
plain := string(bin)
return plain, err
}
// encryptName - encrypt "plainName", return base64-encoded "cipherName64"
// The used encryption is either CBC or EME, depending on "useEME".
func (n *NameTransform) encryptName(plainName string, iv []byte) (cipherName64 string) {
bin := []byte(plainName)
bin = pad16(bin)
if n.useEME {
bin = eme.Transform(n.cryptoCore.BlockCipher, iv, bin, eme.DirectionEncrypt)
} else {
cbc := cipher.NewCBCEncrypter(n.cryptoCore.BlockCipher, iv)
cbc.CryptBlocks(bin, bin)
}
cipherName64 = base64.URLEncoding.EncodeToString(bin)
return cipherName64
}

41
cryptfs/names_diriv.go → internal/nametransform/names_diriv.go
View File

@ -1,4 +1,4 @@
package cryptfs
package nametransform
import (
"fmt"
@ -7,6 +7,17 @@ import (
"path/filepath"
"strings"
"sync"
"github.com/rfjakob/gocryptfs/internal/toggledlog"
"github.com/rfjakob/gocryptfs/internal/cryptocore"
)
const (
// identical to AES block size
dirIVLen = 16
// dirIV is stored in this file. Exported because we have to ignore this
// name in directory listing.
DirIVFilename = "gocryptfs.diriv"
)
// A simple one-entry DirIV cache
@ -50,23 +61,23 @@ func (c *dirIVCache) Clear() {
}
// readDirIV - read the "gocryptfs.diriv" file from "dir" (absolute ciphertext path)
func (be *CryptFS) ReadDirIV(dir string) (iv []byte, readErr error) {
ivfile := filepath.Join(dir, DIRIV_FILENAME)
Debug.Printf("ReadDirIV: reading %s\n", ivfile)
func (be *NameTransform) ReadDirIV(dir string) (iv []byte, readErr error) {
ivfile := filepath.Join(dir, DirIVFilename)
toggledlog.Debug.Printf("ReadDirIV: reading %s\n", ivfile)
iv, readErr = ioutil.ReadFile(ivfile)
if readErr != nil {
// The directory may have been concurrently deleted or moved. Failure to
// read the diriv is not an error in that case.
_, statErr := os.Stat(dir)
if os.IsNotExist(statErr) {
Debug.Printf("ReadDirIV: Dir %s was deleted under our feet", dir)
toggledlog.Debug.Printf("ReadDirIV: Dir %s was deleted under our feet", dir)
} else {
// This should not happen
Warn.Printf("ReadDirIV: Dir exists but diriv does not: %v\n", readErr)
toggledlog.Warn.Printf("ReadDirIV: Dir exists but diriv does not: %v\n", readErr)
}
return nil, readErr
}
if len(iv) != DIRIV_LEN {
if len(iv) != dirIVLen {
return nil, fmt.Errorf("ReadDirIV: Invalid length %d\n", len(iv))
}
return iv, nil
@ -76,14 +87,14 @@ func (be *CryptFS) ReadDirIV(dir string) (iv []byte, readErr error) {
// This function is exported because it is used from pathfs_frontend, main,
// and also the automated tests.
func WriteDirIV(dir string) error {
iv := RandBytes(DIRIV_LEN)
file := filepath.Join(dir, DIRIV_FILENAME)
iv := cryptocore.RandBytes(dirIVLen)
file := filepath.Join(dir, DirIVFilename)
// 0444 permissions: the file is not secret but should not be written to
return ioutil.WriteFile(file, iv, 0444)
}
// EncryptPathDirIV - encrypt path using EME with DirIV
func (be *CryptFS) EncryptPathDirIV(plainPath string, rootDir string, eme bool) (cipherPath string, err error) {
func (be *NameTransform) EncryptPathDirIV(plainPath string, rootDir string) (cipherPath string, err error) {
// Empty string means root directory
if plainPath == "" {
return plainPath, nil
@ -94,7 +105,7 @@ func (be *CryptFS) EncryptPathDirIV(plainPath string, rootDir string, eme bool)
if found {
//fmt.Print("h")
baseName := filepath.Base(plainPath)
cBaseName := be.encryptName(baseName, iv, eme)
cBaseName := be.encryptName(baseName, iv)
cipherPath = cParentDir + "/" + cBaseName
return cipherPath, nil
}
@ -107,7 +118,7 @@ func (be *CryptFS) EncryptPathDirIV(plainPath string, rootDir string, eme bool)
if err != nil {
return "", err
}
encryptedName := be.encryptName(plainName, iv, eme)
encryptedName := be.encryptName(plainName, iv)
encryptedNames = append(encryptedNames, encryptedName)
wd = filepath.Join(wd, encryptedName)
}
@ -119,17 +130,17 @@ func (be *CryptFS) EncryptPathDirIV(plainPath string, rootDir string, eme bool)
}
// DecryptPathDirIV - decrypt path using EME with DirIV
func (be *CryptFS) DecryptPathDirIV(encryptedPath string, rootDir string, eme bool) (string, error) {
func (be *NameTransform) DecryptPathDirIV(encryptedPath string, rootDir string, eme bool) (string, error) {
var wd = rootDir
var plainNames []string
encryptedNames := strings.Split(encryptedPath, "/")
Debug.Printf("DecryptPathDirIV: decrypting %v\n", encryptedNames)
toggledlog.Debug.Printf("DecryptPathDirIV: decrypting %v\n", encryptedNames)
for _, encryptedName := range encryptedNames {
iv, err := be.ReadDirIV(wd)
if err != nil {
return "", err
}
plainName, err := be.decryptName(encryptedName, iv, eme)
plainName, err := be.DecryptName(encryptedName, iv)
if err != nil {
return "", err
}

14
cryptfs/names_noiv.go → internal/nametransform/names_noiv.go
View File

@ -1,4 +1,4 @@
package cryptfs
package nametransform
import (
"strings"
@ -12,7 +12,7 @@ const (
// DecryptPathNoIV - decrypt path using CBC without any IV.
// This function is deprecated by the the more secure DirIV variant and only retained
// for compatability with old filesystems.
func (be *CryptFS) DecryptPathNoIV(cipherPath string) (plainPath string, err error) {
func (be *NameTransform) DecryptPathNoIV(cipherPath string) (plainPath string, err error) {
plainPath, err = be.translatePathNoIV(cipherPath, OpDecrypt)
return plainPath, err
}
@ -20,14 +20,14 @@ func (be *CryptFS) DecryptPathNoIV(cipherPath string) (plainPath string, err err
// EncryptPathNoIV - decrypt path using CBC without any IV.
// This function is deprecated by the the more secure DirIV variant and only retained
// for compatability with old filesystems.
func (be *CryptFS) EncryptPathNoIV(plainPath string) (cipherPath string) {
func (be *NameTransform) EncryptPathNoIV(plainPath string) (cipherPath string) {
cipherPath, _ = be.translatePathNoIV(plainPath, OpEncrypt)
return cipherPath
}
// translatePathZeroIV - encrypt or decrypt path using CBC with an all-zero IV.
// Just splits the string on "/" and hands the parts to encryptName() / decryptName()
func (be *CryptFS) translatePathNoIV(path string, op int) (string, error) {
func (be *NameTransform) translatePathNoIV(path string, op int) (string, error) {
var err error
// Empty string means root directory
@ -35,7 +35,7 @@ func (be *CryptFS) translatePathNoIV(path string, op int) (string, error) {
return path, err
}
zeroIV := make([]byte, DIRIV_LEN)
zeroIV := make([]byte, dirIVLen)
// Run operation on each path component
var translatedParts []string
@ -49,9 +49,9 @@ func (be *CryptFS) translatePathNoIV(path string, op int) (string, error) {
}
var newPart string
if op == OpEncrypt {
newPart = be.encryptName(part, zeroIV, false)
newPart = be.encryptName(part, zeroIV)
} else {
newPart, err = be.decryptName(part, zeroIV, false)
newPart, err = be.DecryptName(part, zeroIV)
if err != nil {
return "", err
}

2
cryptfs/names_test.go → internal/nametransform/names_test.go
View File

@ -1,4 +1,4 @@
package cryptfs
package nametransform
import (
"bytes"

60
internal/nametransform/pad16.go Normal file
View File

@ -0,0 +1,60 @@
package nametransform
import (
"fmt"
"crypto/aes"
"errors"
)
// pad16 - pad data to AES block size (=16 byte) using standard PKCS#7 padding
// https://tools.ietf.org/html/rfc5652#section-6.3
func pad16(orig []byte) (padded []byte) {
oldLen := len(orig)
if oldLen == 0 {
panic("Padding zero-length string makes no sense")
}
padLen := aes.BlockSize - oldLen%aes.BlockSize
if padLen == 0 {
padLen = aes.BlockSize
}
newLen := oldLen + padLen
padded = make([]byte, newLen)
copy(padded, orig)
padByte := byte(padLen)
for i := oldLen; i < newLen; i++ {
padded[i] = padByte
}
return padded
}
// unPad16 - remove padding
func unPad16(padded []byte) ([]byte, error) {
oldLen := len(padded)
if oldLen%aes.BlockSize != 0 {
return nil, errors.New("Unaligned size")
}
// The last byte is always a padding byte
padByte := padded[oldLen-1]
// The padding byte's value is the padding length
padLen := int(padByte)
// Padding must be at least 1 byte
if padLen <= 0 {
return nil, errors.New("Padding cannot be zero-length")
}
// Larger paddings make no sense
if padLen > aes.BlockSize {
return nil, fmt.Errorf("Padding too long, padLen = %d > 16", padLen)
}
// All padding bytes must be identical
for i := oldLen - padLen; i < oldLen; i++ {
if padded[i] != padByte {
return nil, fmt.Errorf("Padding byte at i=%d is invalid", i)
}
}
newLen := oldLen - padLen
// Padding an empty string makes no sense
if newLen == 0 {
return nil, errors.New("Unpadded length is zero")
}
return padded[0:newLen], nil
}

6
cryptfs/log.go → internal/toggledlog/log.go
View File

@ -1,4 +1,4 @@
package cryptfs
package toggledlog
import (
"encoding/json"
@ -7,6 +7,10 @@ import (
"os"
)
const (
ProgramName = "gocryptfs"
)
func JSONDump(obj interface{}) string {
b, err := json.MarshalIndent(obj, "", "\t")
if err != nil {

2
cryptfs/log_go1.4.go → internal/toggledlog/log_go1.4.go
View File

@ -1,7 +1,7 @@
// +build !go1.5
// = go 1.4 or lower
package cryptfs
package toggledlog
import (
"log/syslog"

4
cryptfs/log_go1.5.go → internal/toggledlog/log_go1.5.go
View File

@ -1,14 +1,14 @@
// +build go1.5
// = go 1.5 or higher
package cryptfs
package toggledlog
import (
"log/syslog"
)
func (l *toggledLogger) SwitchToSyslog(p syslog.Priority) {
w, err := syslog.New(p, PROGRAM_NAME)
w, err := syslog.New(p, ProgramName)
if err != nil {
Warn.Printf("Cannot switch 0x%02x to syslog: %v", p, err)
} else {

106
main.go
View File

@ -16,12 +16,16 @@ import (
"golang.org/x/crypto/ssh/terminal"
"github.com/rfjakob/gocryptfs/cryptfs"
"github.com/rfjakob/gocryptfs/pathfs_frontend"
"github.com/hanwen/go-fuse/fuse"
"github.com/hanwen/go-fuse/fuse/nodefs"
"github.com/hanwen/go-fuse/fuse/pathfs"
"github.com/rfjakob/gocryptfs/pathfs_frontend"
"github.com/rfjakob/gocryptfs/internal/configfile"
"github.com/rfjakob/gocryptfs/internal/toggledlog"
"github.com/rfjakob/gocryptfs/internal/nametransform"
"github.com/rfjakob/gocryptfs/internal/contentenc"
"github.com/rfjakob/gocryptfs/internal/cryptocore"
)
const (
@ -56,9 +60,9 @@ func initDir(args *argContainer) {
}
// Create gocryptfs.conf
cryptfs.Info.Printf("Choose a password for protecting your files.")
toggledlog.Info.Printf("Choose a password for protecting your files.")
password := readPasswordTwice(args.extpass)
err = cryptfs.CreateConfFile(args.config, password, args.plaintextnames, args.scryptn)
err = configfile.CreateConfFile(args.config, password, args.plaintextnames, args.scryptn)
if err != nil {
fmt.Println(err)
os.Exit(ERREXIT_INIT)
@ -66,30 +70,30 @@ func initDir(args *argContainer) {
if args.diriv && !args.plaintextnames {