blob: 39e07fae04a51acf45a10b58c001287c21462435 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
{- Copyright 2016 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
{-# LANGUAGE DeriveGeneric, BangPatterns #-}
module BackupRecord where
import Types
import Types.Cost
import Types.Server
import GHC.Generics
import Data.Time.Clock.POSIX
import Data.Aeson
import Data.Maybe
import System.FilePath
import System.Directory
import System.Posix.User
import System.Posix.Files
import qualified Data.ByteString.Lazy as B
-- | Record of a backup.
--
-- If an attacker cracks the user's system and finds this stored
-- on it, it should not help them recover keys from keysafe.
--
-- That's why the Name used is not included; as knowing the name lets
-- an attacker download shards and start password cracking.
--
-- Including the password entropy does let an attacker avoid trying
-- weak passwords and go right to passwords that are strong enough, but
-- this should only half the password crack time at worst.
data BackupRecord = BackupRecord
{ backupDate :: POSIXTime
, backupServers :: [HostName]
, secretKeySource :: String
, passwordEntropy :: Int
} deriving (Show, Generic)
-- BackupRecord is serialized as JSON.
instance ToJSON BackupRecord
instance FromJSON BackupRecord
mkBackupRecord :: [Server] -> SecretKeySource -> Entropy UnknownPassword -> IO BackupRecord
mkBackupRecord servers sks (Entropy n) = BackupRecord
<$> getPOSIXTime
<*> pure (map serverName servers)
<*> pure (show sks)
<*> pure n
backupRecordFile :: IO FilePath
backupRecordFile = do
u <- getUserEntryForID =<< getEffectiveUserID
return $ homeDirectory u </> ".keysafe/backup.log"
readBackupRecords :: IO [BackupRecord]
readBackupRecords = do
f <- backupRecordFile
e <- doesFileExist f
if e
then fromMaybe [] . decode <$> B.readFile f
else return []
storeBackupRecord :: BackupRecord -> IO ()
storeBackupRecord r = do
!rs <- readBackupRecords
f <- backupRecordFile
let d = takeDirectory f
createDirectoryIfMissing True d
setFileMode d $
ownerReadMode
`unionFileModes` ownerWriteMode
`unionFileModes` ownerExecuteMode
setPermissions d
$ setOwnerReadable True
$ setOwnerWritable True
$ setOwnerExecutable True emptyPermissions
B.writeFile f $ encode (r:rs)
|
