use hmac in balanced preferred content
This deals with the possible security problem that someone could make an unusually low UUID and generate keys that are all constructed to hash to a number that, mod the number of repositories in the group, == 0. So balanced preferred content would always put those keys in the repository with the low UUID as long as the group contains the number of repositories that the attacker anticipated. Presumably the attacker than holds the data for ransom? Dunno. Anyway, the partial solution is to use HMAC (sha256) with all the UUIDs combined together as the "secret", and the key as the "message". Now any change in the set of UUIDs in a group will invalidate the attacker's constructed keys from hashing to anything in particular. Given that there are plenty of other things someone can do if they can write to the repository -- including modifying preferred content so only their repository wants files, and numcopies so other repositories drom them -- this seems like safeguard enough. Note that, in balancedPicker, combineduuids is memoized.
This commit is contained in:
parent
bde58e6c71
commit
bd5affa362
10 changed files with 68 additions and 47 deletions
|
@ -6,6 +6,7 @@
|
|||
-}
|
||||
|
||||
{-# LANGUAGE BangPatterns, PackageImports #-}
|
||||
{-# LANGUAGE RankNTypes #-}
|
||||
{-# LANGUAGE CPP #-}
|
||||
|
||||
module Utility.Hash (
|
||||
|
@ -16,7 +17,6 @@ module Utility.Hash (
|
|||
sha2_224_context,
|
||||
sha2_256,
|
||||
sha2_256_context,
|
||||
sha2_256s,
|
||||
sha2_384,
|
||||
sha2_384_context,
|
||||
sha2_512,
|
||||
|
@ -107,9 +107,6 @@ sha2_256 = hashlazy
|
|||
sha2_256_context :: Context SHA256
|
||||
sha2_256_context = hashInit
|
||||
|
||||
sha2_256s :: S.ByteString -> Digest SHA256
|
||||
sha2_256s = hash
|
||||
|
||||
sha2_384 :: L.ByteString -> Digest SHA384
|
||||
sha2_384 = hashlazy
|
||||
|
||||
|
@ -267,25 +264,26 @@ data Mac = HmacSha1 | HmacSha224 | HmacSha256 | HmacSha384 | HmacSha512
|
|||
deriving (Eq)
|
||||
|
||||
calcMac
|
||||
:: Mac -- ^ MAC
|
||||
:: (forall a. Digest a -> t) -- ^ applied to MAC'ed message
|
||||
-> Mac -- ^ MAC
|
||||
-> S.ByteString -- ^ secret key
|
||||
-> S.ByteString -- ^ message
|
||||
-> String -- ^ MAC'ed message, in hexadecimal
|
||||
calcMac mac = case mac of
|
||||
-> t
|
||||
calcMac f mac = case mac of
|
||||
HmacSha1 -> use SHA1
|
||||
HmacSha224 -> use SHA224
|
||||
HmacSha256 -> use SHA256
|
||||
HmacSha384 -> use SHA384
|
||||
HmacSha512 -> use SHA512
|
||||
where
|
||||
use alg k m = show (hmacGetDigest (hmacWitnessAlg alg k m))
|
||||
use alg k m = f (hmacGetDigest (hmacWitnessAlg alg k m))
|
||||
|
||||
hmacWitnessAlg :: HashAlgorithm a => a -> S.ByteString -> S.ByteString -> HMAC a
|
||||
hmacWitnessAlg _ = hmac
|
||||
|
||||
-- Check that all the MACs continue to produce the same.
|
||||
props_macs_stable :: [(String, Bool)]
|
||||
props_macs_stable = map (\(desc, mac, result) -> (desc ++ " stable", calcMac mac key msg == result))
|
||||
props_macs_stable = map (\(desc, mac, result) -> (desc ++ " stable", calcMac show mac key msg == result))
|
||||
[ ("HmacSha1", HmacSha1, "46b4ec586117154dacd49d664e5d63fdc88efb51")
|
||||
, ("HmacSha224", HmacSha224, "4c1f774863acb63b7f6e9daa9b5c543fa0d5eccf61e3ffc3698eacdd")
|
||||
, ("HmacSha256", HmacSha256, "f9320baf0249169e73850cd6156ded0106e2bb6ad8cab01b7bbbebe6d1065317")
|
||||
|
|
Loading…
Add table
Add a link
Reference in a new issue