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reverse: add panics against API abuse

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These should help prevent later programming errors.
This commit is contained in:
Jakob Unterwurzacher 2016-10-09 17:05:12 +02:00
parent f754c8a200
commit d3b78fea95
2 changed files with 10 additions and 2 deletions
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4
internal/cryptocore/cryptocore.go
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@ -72,6 +72,10 @@ func New(key []byte, backend BackendTypeEnum, IVBitLen int) *CryptoCore {
case BackendGoGCM: case BackendGoGCM:
aeadCipher, err = goGCMWrapper(blockCipher, IVLen) aeadCipher, err = goGCMWrapper(blockCipher, IVLen)
case BackendAESSIV: case BackendAESSIV:
if IVLen != 16 {
// SIV supports any nonce size, but we only use 16.
panic("AES-SIV must use 16-byte nonces")
}
// AES-SIV uses 1/2 of the key for authentication, 1/2 for // AES-SIV uses 1/2 of the key for authentication, 1/2 for
// encryption, so we need a 64-bytes key for AES-256. Derive it from // encryption, so we need a 64-bytes key for AES-256. Derive it from
// the master key by hashing it with SHA-512. // the master key by hashing it with SHA-512.

8
internal/fusefrontend_reverse/rfs.go
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@ -46,10 +46,14 @@ type reverseFS struct {
var _ pathfs.FileSystem = &reverseFS{} var _ pathfs.FileSystem = &reverseFS{}
// NewFS returns an encrypted FUSE overlay filesystem // NewFS returns an encrypted FUSE overlay filesystem.
// In this case (reverse mode) the backing directory is plain-text and
// reverseFS provides an encrypted view.
func NewFS(args fusefrontend.Args) pathfs.FileSystem { func NewFS(args fusefrontend.Args) pathfs.FileSystem {
if args.CryptoBackend != cryptocore.BackendAESSIV {
panic("reverse mode must use AES-SIV, everything else is insecure")
}
initLongnameCache() initLongnameCache()
cryptoCore := cryptocore.New(args.Masterkey, args.CryptoBackend, contentenc.DefaultIVBits) cryptoCore := cryptocore.New(args.Masterkey, args.CryptoBackend, contentenc.DefaultIVBits)
contentEnc := contentenc.New(cryptoCore, contentenc.DefaultBS) contentEnc := contentenc.New(cryptoCore, contentenc.DefaultBS)
nameTransform := nametransform.New(cryptoCore, args.LongNames) nameTransform := nametransform.New(cryptoCore, args.LongNames)