contentenc: add GCM-SIV support

Also add ReverseDummyNonce nonce generation.

2 files changed, 20 insertions, 3 deletions

diff --git a/internal/configfile/config_file.go b/internal/configfile/config_file.go
index 178890b..b1504b4 100644
--- a/internal/configfile/config_file.go
+++ b/internal/configfile/config_file.go
@@ -45,7 +45,7 @@ type ConfFile struct {
 // CreateConfFile - create a new config with a random key encrypted with
 // "password" and write it to "filename".
 // Uses scrypt with cost parameter logN.
-func CreateConfFile(filename string, password string, plaintextNames bool, logN int, creator string) error {
+func CreateConfFile(filename string, password string, plaintextNames bool, logN int, creator string, reverse bool) error {
 	var cf ConfFile
 	cf.filename = filename
 	cf.Creator = creator
@@ -67,6 +67,9 @@ func CreateConfFile(filename string, password string, plaintextNames bool, logN
 		cf.FeatureFlags = append(cf.FeatureFlags, knownFlags[FlagEMENames])
 		cf.FeatureFlags = append(cf.FeatureFlags, knownFlags[FlagLongNames])
 	}
+	if reverse {
+		cf.FeatureFlags = append(cf.FeatureFlags, knownFlags[FlagGCMSIV])
+	}
 
 	// Write file to disk
 	return cf.WriteFile()
@@ -165,7 +168,7 @@ func (cf *ConfFile) EncryptKey(key []byte, password string, logN int) {
 	// Lock master key using password-based key
 	cc := cryptocore.New(scryptHash, cryptocore.BackendGoGCM, 96)
 	ce := contentenc.New(cc, 4096)
-	cf.EncryptedKey = ce.EncryptBlock(key, 0, nil)
+	cf.EncryptedKey = ce.EncryptBlock(key, 0, nil, contentenc.RandomNonce)
 }
 
 // WriteFile - write out config in JSON format to file "filename.tmp"
diff --git a/internal/configfile/config_test.go b/internal/configfile/config_test.go
index e34a3cd..72c25f6 100644
--- a/internal/configfile/config_test.go
+++ b/internal/configfile/config_test.go
@@ -60,7 +60,7 @@ func TestLoadV2StrangeFeature(t *testing.T) {
 }
 
 func TestCreateConfFile(t *testing.T) {
-	err := CreateConfFile("config_test/tmp.conf", "test", false, 10, "test")
+	err := CreateConfFile("config_test/tmp.conf", "test", false, 10, "test", false)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -71,6 +71,20 @@ func TestCreateConfFile(t *testing.T) {
 
 }
 
+func TestCreateConfFileReverse(t *testing.T) {
+	err := CreateConfFile("config_test/tmp.conf", "test", false, 10, "test", true)
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, c, err := LoadConfFile("config_test/tmp.conf", "test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !c.IsFeatureFlagSet(FlagGCMSIV) {
+		t.Error("GCMSIV flag should be set but is not")
+	}
+}
+
 func TestIsFeatureFlagKnown(t *testing.T) {
 	// Test a few hardcoded values
 	testKnownFlags := []string{"DirIV", "PlaintextNames", "EMENames", "GCMIV128", "LongNames"}