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

1 files changed, 56 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,
+	}
+}