diff options
| -rw-r--r-- | Crypto.hs | 35 | ||||
| -rw-r--r-- | doc/bugs/S3_bucket_uses_the_same_key_for_encryption_and_hashing.mdwn | 4 |
2 files changed, 29 insertions, 10 deletions
@@ -45,6 +45,24 @@ import RemoteClass import Utility import CryptoTypes +{- The first half of a Cipher is used for HMAC; the remainder + - is used as the GPG symmetric encryption passphrase. + - + - 256 is enough for gpg's symetric cipher; unlike weaker public key + - crypto, the key does not need to be too large. + -} +cipherHalf :: Int +cipherHalf = 256 + +cipherSize :: Int +cipherSize = cipherHalf * 2 + +cipherPassphrase :: Cipher -> String +cipherPassphrase (Cipher c) = drop cipherHalf c + +cipherHmac :: Cipher -> String +cipherHmac (Cipher c) = take cipherHalf c + {- Creates a new Cipher, encrypted as specified in the remote's configuration -} genCipher :: RemoteConfig -> IO EncryptedCipher genCipher c = do @@ -58,10 +76,10 @@ genCipher c = do -- newline. [ Params "--gen-random --armor" , Param $ show randomquality - , Param $ show ciphersize + , Param $ show cipherSize ] - randomquality = 1 :: Int -- 1 is /dev/urandom; 2 is /dev/random - ciphersize = 256 :: Int + -- 1 is /dev/urandom; 2 is /dev/random + randomquality = 1 :: Int {- Updates an existing Cipher, re-encrypting it to add KeyIds specified in - the remote's configuration. -} @@ -110,10 +128,11 @@ decryptCipher _ (EncryptedCipher encipher _) = - reversable, nor does it need to be the same type of encryption used - on content. It does need to be repeatable. -} encryptKey :: Cipher -> Key -> IO Key -encryptKey (Cipher c) k = +encryptKey c k = return Key { - keyName = showDigest $ - hmacSha1 (fromString $ show k) (fromString c), + keyName = showDigest $ hmacSha1 + (fromString $ show k) + (fromString $ cipherHmac c), keyBackendName = "GPGHMACSHA1", keySize = Nothing, -- size and mtime omitted keyMtime = Nothing -- to avoid leaking data @@ -153,12 +172,12 @@ gpgPipeStrict params input = do {- Runs gpg with a cipher and some parameters, feeding it an input, - and passing a handle to its output to an action. -} gpgCipherHandle :: [CommandParam] -> Cipher -> L.ByteString -> (Handle -> IO a) -> IO a -gpgCipherHandle params (Cipher c) input a = do +gpgCipherHandle params c input a = do -- pipe the passphrase into gpg on a fd (frompipe, topipe) <- createPipe _ <- forkIO $ do toh <- fdToHandle topipe - hPutStrLn toh c + hPutStrLn toh $ cipherPassphrase c hClose toh let Fd passphrasefd = frompipe let passphrase = [Param "--passphrase-fd", Param $ show passphrasefd] diff --git a/doc/bugs/S3_bucket_uses_the_same_key_for_encryption_and_hashing.mdwn b/doc/bugs/S3_bucket_uses_the_same_key_for_encryption_and_hashing.mdwn index 1980a8f44..9fc31fa48 100644 --- a/doc/bugs/S3_bucket_uses_the_same_key_for_encryption_and_hashing.mdwn +++ b/doc/bugs/S3_bucket_uses_the_same_key_for_encryption_and_hashing.mdwn @@ -4,5 +4,5 @@ Also, ttbomk, HMAC needs two keys, not one. Are you re-using the same key twice? Compability for old buckets and support for different ones can be maintained by introducing a new option and simply copying over the encryption key's identifier into this new option should it be missing. -> See [[design/encryption]]. I don't think this bug needs to be kept -> open. [[done]] --[[Joey]] +> Bug was filed prematurely, but was a good bit of paranoia, and gpg and +> hmac are given different secret keys [[done]] --[[Joey]] |