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package configfile
import (
"fmt"
"github.com/rfjakob/gocryptfs/v2/internal/contentenc"
)
// Validate that the combination of settings makes sense and is supported
func (cf *ConfFile) Validate() error {
if cf.Version != contentenc.CurrentVersion {
return fmt.Errorf("Unsupported on-disk format %d", cf.Version)
}
// scrypt params ok?
if err := cf.ScryptObject.validateParams(); err != nil {
return err
}
// All feature flags that are in the config file are known?
for _, flag := range cf.FeatureFlags {
if !isFeatureFlagKnown(flag) {
return fmt.Errorf("Unknown feature flag %q", flag)
}
}
// File content encryption
{
if cf.IsFeatureFlagSet(FlagXChaCha20Poly1305) && cf.IsFeatureFlagSet(FlagAESSIV) {
return fmt.Errorf("Can't have both XChaCha20Poly1305 and AESSIV feature flags")
}
if cf.IsFeatureFlagSet(FlagAESSIV) && !cf.IsFeatureFlagSet(FlagGCMIV128) {
return fmt.Errorf("AESSIV requires GCMIV128 feature flag")
}
if cf.IsFeatureFlagSet(FlagXChaCha20Poly1305) {
if cf.IsFeatureFlagSet(FlagGCMIV128) {
return fmt.Errorf("XChaCha20Poly1305 conflicts with GCMIV128 feature flag")
}
if !cf.IsFeatureFlagSet(FlagHKDF) {
return fmt.Errorf("XChaCha20Poly1305 requires HKDF feature flag")
}
}
// The absence of other flags means AES-GCM (oldest algorithm)
if !cf.IsFeatureFlagSet(FlagXChaCha20Poly1305) && !cf.IsFeatureFlagSet(FlagAESSIV) {
if !cf.IsFeatureFlagSet(FlagGCMIV128) {
return fmt.Errorf("AES-GCM requires GCMIV128 feature flag")
}
}
}
// Filename encryption
{
if cf.IsFeatureFlagSet(FlagPlaintextNames) && cf.IsFeatureFlagSet(FlagEMENames) {
return fmt.Errorf("Can't have both PlaintextNames and EMENames feature flags")
}
if cf.IsFeatureFlagSet(FlagPlaintextNames) {
if cf.IsFeatureFlagSet(FlagDirIV) {
return fmt.Errorf("PlaintextNames conflicts with DirIV feature flag")
}
if cf.IsFeatureFlagSet(FlagLongNames) {
return fmt.Errorf("PlaintextNames conflicts with LongNames feature flag")
}
if cf.IsFeatureFlagSet(FlagRaw64) {
return fmt.Errorf("PlaintextNames conflicts with Raw64 feature flag")
}
}
if cf.IsFeatureFlagSet(FlagEMENames) {
// All combinations of DirIV, LongNames, Raw64 allowed
}
}
return nil
}
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