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authorJakob Unterwurzacher2016-02-06 19:20:54 +0100
committerJakob Unterwurzacher2016-02-06 19:22:35 +0100
commit2b8cbd944149afe51fadddbd67ee4499d1d86250 (patch)
tree76361984cc4394bbb9b19ae987aeaff71fb6073b /internal/cryptocore
parentadcfbd79a8b8bb85cbee25996ab622a05de0dbc1 (diff)
Major refactoring: Split up "cryptfs" into several internal packages
"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
Diffstat (limited to 'internal/cryptocore')
-rw-r--r--internal/cryptocore/crypto_api.go56
-rw-r--r--internal/cryptocore/gcm_go1.4.go22
-rw-r--r--internal/cryptocore/gcm_go1.5.go16
-rw-r--r--internal/cryptocore/nonce.go44
-rw-r--r--internal/cryptocore/openssl_aead.go100
-rwxr-xr-xinternal/cryptocore/openssl_benchmark.bash3
-rw-r--r--internal/cryptocore/openssl_test.go75
7 files changed, 316 insertions, 0 deletions
diff --git a/internal/cryptocore/crypto_api.go b/internal/cryptocore/crypto_api.go
new file mode 100644
index 0000000..c6b6869
--- /dev/null
+++ b/internal/cryptocore/crypto_api.go
@@ -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,
+ }
+}
diff --git a/internal/cryptocore/gcm_go1.4.go b/internal/cryptocore/gcm_go1.4.go
new file mode 100644
index 0000000..dba222c
--- /dev/null
+++ b/internal/cryptocore/gcm_go1.4.go
@@ -0,0 +1,22 @@
+// +build !go1.5
+// = go 1.4 or lower
+
+package cryptocore
+
+import (
+ "crypto/cipher"
+ "fmt"
+)
+
+// goGCMWrapper - This wrapper makes sure gocryptfs can be compiled on Go
+// versions 1.4 and lower that lack NewGCMWithNonceSize().
+// 128 bit GCM IVs will not work when using built-in Go crypto, obviously, when
+// compiled on 1.4.
+func goGCMWrapper(bc cipher.Block, nonceSize int) (cipher.AEAD, error) {
+ if nonceSize != 12 {
+ Warn.Printf("128 bit GCM IVs are not supported by Go 1.4 and lower.")
+ Warn.Printf("Please use openssl crypto or recompile using a newer Go runtime.")
+ return nil, fmt.Errorf("128 bit GCM IVs are not supported by Go 1.4 and lower")
+ }
+ return cipher.NewGCM(bc)
+}
diff --git a/internal/cryptocore/gcm_go1.5.go b/internal/cryptocore/gcm_go1.5.go
new file mode 100644
index 0000000..0c9b1a5
--- /dev/null
+++ b/internal/cryptocore/gcm_go1.5.go
@@ -0,0 +1,16 @@
+// +build go1.5
+// = go 1.5 or higher
+
+package cryptocore
+
+import (
+ "crypto/cipher"
+)
+
+// goGCMWrapper - This wrapper makes sure gocryptfs can be compiled on Go
+// versions 1.4 and lower that lack NewGCMWithNonceSize().
+// 128 bit GCM IVs will not work when using built-in Go crypto, obviously, when
+// compiled on 1.4.
+func goGCMWrapper(bc cipher.Block, nonceSize int) (cipher.AEAD, error) {
+ return cipher.NewGCMWithNonceSize(bc, nonceSize)
+}
diff --git a/internal/cryptocore/nonce.go b/internal/cryptocore/nonce.go
new file mode 100644
index 0000000..72d8588
--- /dev/null
+++ b/internal/cryptocore/nonce.go
@@ -0,0 +1,44 @@
+package cryptocore
+
+import (
+ "bytes"
+ "crypto/rand"
+ "encoding/binary"
+ "encoding/hex"
+ "fmt"
+
+ "github.com/rfjakob/gocryptfs/internal/toggledlog"
+)
+
+// Get "n" random bytes from /dev/urandom or panic
+func RandBytes(n int) []byte {
+ b := make([]byte, n)
+ _, err := rand.Read(b)
+ if err != nil {
+ panic("Failed to read random bytes: " + err.Error())
+ }
+ return b
+}
+
+// Return a secure random uint64
+func RandUint64() uint64 {
+ b := RandBytes(8)
+ return binary.BigEndian.Uint64(b)
+}
+
+type nonceGenerator struct {
+ lastNonce []byte
+ nonceLen int // bytes
+}
+
+// Get a random "nonceLen"-byte nonce
+func (n *nonceGenerator) Get() []byte {
+ nonce := RandBytes(n.nonceLen)
+ 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)
+ }
+ n.lastNonce = nonce
+ return nonce
+}
diff --git a/internal/cryptocore/openssl_aead.go b/internal/cryptocore/openssl_aead.go
new file mode 100644
index 0000000..d4ed64b
--- /dev/null
+++ b/internal/cryptocore/openssl_aead.go
@@ -0,0 +1,100 @@
+package cryptocore
+
+// Implements cipher.AEAD with OpenSSL backend
+
+import (
+ "bytes"
+ "github.com/spacemonkeygo/openssl"
+)
+
+// Supports all nonce sizes
+type opensslGCM struct {
+ key []byte
+}
+
+func (be opensslGCM) Overhead() int {
+ return AuthTagLen
+}
+
+func (be opensslGCM) NonceSize() int {
+ // We support any nonce size
+ return -1
+}
+
+// Seal encrypts and authenticates plaintext, authenticates the
+// additional data and appends the result to dst, returning the updated
+// slice. opensslGCM supports any nonce size.
+func (be opensslGCM) Seal(dst, nonce, plaintext, data []byte) []byte {
+
+ // Preallocate output buffer
+ var cipherBuf bytes.Buffer
+ cipherBuf.Grow(len(dst) + len(plaintext) + AuthTagLen)
+ // Output will be appended to dst
+ cipherBuf.Write(dst)
+
+ ectx, err := openssl.NewGCMEncryptionCipherCtx(KeyLen*8, nil, be.key, nonce)
+ if err != nil {
+ panic(err)
+ }
+ err = ectx.ExtraData(data)
+ if err != nil {
+ panic(err)
+ }
+ part, err := ectx.EncryptUpdate(plaintext)
+ if err != nil {
+ panic(err)
+ }
+ cipherBuf.Write(part)
+ part, err = ectx.EncryptFinal()
+ if err != nil {
+ panic(err)
+ }
+ cipherBuf.Write(part)
+ part, err = ectx.GetTag()
+ if err != nil {
+ panic(err)
+ }
+ cipherBuf.Write(part)
+
+ return cipherBuf.Bytes()
+}
+
+// Open decrypts and authenticates ciphertext, authenticates the
+// additional data and, if successful, appends the resulting plaintext
+// to dst, returning the updated slice. The nonce must be NonceSize()
+// bytes long and both it and the additional data must match the
+// value passed to Seal.
+//
+// The ciphertext and dst may alias exactly or not at all.
+func (be opensslGCM) Open(dst, nonce, ciphertext, data []byte) ([]byte, error) {
+
+ l := len(ciphertext)
+ tag := ciphertext[l-AuthTagLen : l]
+ ciphertext = ciphertext[0 : l-AuthTagLen]
+ plainBuf := bytes.NewBuffer(dst)
+
+ dctx, err := openssl.NewGCMDecryptionCipherCtx(KeyLen*8, nil, be.key, nonce)
+ if err != nil {
+ return nil, err
+ }
+ err = dctx.ExtraData(data)
+ if err != nil {
+ return nil, err
+ }
+ part, err := dctx.DecryptUpdate(ciphertext)
+ if err != nil {
+ return nil, err
+ }
+ plainBuf.Write(part)
+ err = dctx.SetTag(tag)
+ if err != nil {
+ return nil, err
+ }
+ part, err = dctx.DecryptFinal()
+ if err != nil {
+ return nil, err
+ }
+ plainBuf.Write(part)
+
+ return plainBuf.Bytes(), nil
+}
diff --git a/internal/cryptocore/openssl_benchmark.bash b/internal/cryptocore/openssl_benchmark.bash
new file mode 100755
index 0000000..df29628
--- /dev/null
+++ b/internal/cryptocore/openssl_benchmark.bash
@@ -0,0 +1,3 @@
+#!/bin/bash
+
+go test -run NONE -bench BenchmarkEnc
diff --git a/internal/cryptocore/openssl_test.go b/internal/cryptocore/openssl_test.go
new file mode 100644
index 0000000..94b696a
--- /dev/null
+++ b/internal/cryptocore/openssl_test.go
@@ -0,0 +1,75 @@
+package cryptocore
+
+// Benchmark go built-int GCM against spacemonkey openssl bindings
+//
+// Note: The benchmarks in this file supersede the ones in the openssl_benchmark
+// directory as they use the same code paths that gocryptfs actually uses.
+//
+// Run benchmark:
+// go test -bench Enc
+
+import (
+ "crypto/aes"
+ "testing"
+)
+
+func benchmarkGoEnc(b *testing.B, plaintext []byte, key []byte, nonce []byte) (ciphertext []byte) {
+ b.SetBytes(int64(len(plaintext)))
+ aes, err := aes.NewCipher(key[:])
+ if err != nil {
+ b.Fatal(err)
+ }
+ aesgcm, err := goGCMWrapper(aes, len(nonce))
+ if err != nil {
+ b.Fatal(err)
+ }
+ // This would be fileID + blockNo
+ aData := make([]byte, 24)
+ b.ResetTimer()
+ for i := 0; i < b.N; i++ {
+ // Encrypt plaintext and append to nonce
+ ciphertext = aesgcm.Seal(nonce, nonce, plaintext, aData)
+ }
+ return ciphertext
+}
+
+func benchmarkOpensslEnc(b *testing.B, plaintext []byte, key []byte, nonce []byte) (ciphertext []byte) {
+ b.SetBytes(int64(len(plaintext)))
+ var aesgcm opensslGCM
+ aesgcm.key = key
+ // This would be fileID + blockNo
+ aData := make([]byte, 24)
+ for i := 0; i < b.N; i++ {
+ // Encrypt plaintext and append to nonce
+ ciphertext = aesgcm.Seal(nonce, nonce, plaintext, aData)
+ }
+ return ciphertext
+}
+
+func BenchmarkEnc_Go_4k_AES256_nonce96(b *testing.B) {
+ plaintext := make([]byte, 4048)
+ key := make([]byte, 256/8)
+ nonce := make([]byte, 96/8)
+ benchmarkGoEnc(b, plaintext, key, nonce)
+}
+
+func BenchmarkEnc_Go_4k_AES256_nonce128(b *testing.B) {
+ plaintext := make([]byte, 4048)
+ key := make([]byte, 256/8)
+ nonce := make([]byte, 128/8)
+ benchmarkGoEnc(b, plaintext, key, nonce)
+}
+
+func BenchmarkEnc_OpenSSL_4k_AES256_nonce96(b *testing.B) {
+ plaintext := make([]byte, 4048)
+ key := make([]byte, 256/8)
+ nonce := make([]byte, 96/8)
+ benchmarkOpensslEnc(b, plaintext, key, nonce)
+}
+
+func BenchmarkEnc_OpenSSL_4k_AES256_nonce128(b *testing.B) {
+ plaintext := make([]byte, 4048)
+ key := make([]byte, 256/8)
+ nonce := make([]byte, 96/8)
+ benchmarkOpensslEnc(b, plaintext, key, nonce)
+}