git-annex/Utility/Gpg.hs
guilhem ac9807c887 Leverage an ambiguities between Ciphers
Cipher is now a datatype

    data Cipher = Cipher String | MacOnlyCipher String

which makes more precise its interpretation MAC-only vs. MAC + used to
derive a key for symmetric crypto.
2013-09-05 11:09:08 -04:00

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{- gpg interface
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE CPP #-}
module Utility.Gpg where
import Control.Applicative
import Control.Concurrent
import Common
import qualified Build.SysConfig as SysConfig
#ifndef mingw32_HOST_OS
import System.Posix.Types
import Control.Exception (bracket)
import System.Path
import Utility.Env
#else
import Utility.Tmp
#endif
newtype KeyIds = KeyIds { keyIds :: [String] }
deriving (Ord, Eq)
{- If a specific gpg command was found at configure time, use it.
- Otherwise, try to run gpg. -}
gpgcmd :: FilePath
gpgcmd = fromMaybe "gpg" SysConfig.gpg
-- Generate an argument list to asymetrically encrypt to the given recipients.
pkEncTo :: [String] -> [CommandParam]
pkEncTo = concatMap (\r -> [Param "--recipient", Param r])
stdParams :: [CommandParam] -> IO [String]
stdParams params = do
#ifndef mingw32_HOST_OS
-- Enable batch mode if GPG_AGENT_INFO is set, to avoid extraneous
-- gpg output about password prompts. GPG_BATCH is set by the test
-- suite for a similar reason.
e <- getEnv "GPG_AGENT_INFO"
b <- getEnv "GPG_BATCH"
let batch = if isNothing e && isNothing b
then []
else ["--batch", "--no-tty", "--use-agent"]
return $ batch ++ defaults ++ toCommand params
#else
return $ defaults ++ toCommand params
#endif
where
-- Be quiet, even about checking the trustdb. If the one of the
-- default param is already present in 'params', don't include it
-- twice in the output list.
defaults = ["--quiet", "--trust-model", "always"]
{- Usual options for symmetric / public-key encryption. -}
stdEncryptionParams :: Bool -> [CommandParam]
stdEncryptionParams symmetric = [enc symmetric, Param "--force-mdc"]
where
enc True = Param "--symmetric"
-- Force gpg to only encrypt to the specified recipients, not
-- configured defaults. Recipients are assumed to be specified in
-- elsewhere.
enc False = Params "--encrypt --no-encrypt-to --no-default-recipient"
{- Runs gpg with some params and returns its stdout, strictly. -}
readStrict :: [CommandParam] -> IO String
readStrict params = do
params' <- stdParams params
withHandle StdoutHandle createProcessSuccess (proc gpgcmd params') $ \h -> do
hSetBinaryMode h True
hGetContentsStrict h
{- Runs gpg, piping an input value to it, and returning its stdout,
- strictly. -}
pipeStrict :: [CommandParam] -> String -> IO String
pipeStrict params input = do
params' <- stdParams params
withBothHandles createProcessSuccess (proc gpgcmd params') $ \(to, from) -> do
hSetBinaryMode to True
hSetBinaryMode from True
hPutStr to input
hClose to
hGetContentsStrict from
{- Runs gpg with some parameters. First sends it a passphrase (unless it
- is empty) via '--passphrase-fd'. Then runs a feeder action that is
- passed a handle and should write to it all the data to input to gpg.
- Finally, runs a reader action that is passed a handle to gpg's
- output.
-
- Runs gpg in batch mode; this is necessary to avoid gpg 2.x prompting for
- the passphrase.
-
- Note that to avoid deadlock with the cleanup stage,
- the reader must fully consume gpg's input before returning. -}
feedRead :: [CommandParam] -> String -> (Handle -> IO ()) -> (Handle -> IO a) -> IO a
feedRead params passphrase feeder reader = do
#ifndef mingw32_HOST_OS
-- pipe the passphrase into gpg on a fd
(frompipe, topipe) <- createPipe
void $ forkIO $ do
toh <- fdToHandle topipe
hPutStrLn toh passphrase
hClose toh
let Fd pfd = frompipe
let passphrasefd = [Param "--passphrase-fd", Param $ show pfd]
closeFd frompipe `after` go (passphrasefd ++ params)
#else
-- store the passphrase in a temp file for gpg
withTmpFile "gpg" $ \tmpfile h -> do
hPutStr h passphrase
hClose h
let passphrasefile = [Param "--passphrase-file", File tmpfile]
go $ passphrasefile ++ params
#endif
where
go params' = pipeLazy params' feeder reader
{- Like feedRead, but without passphrase. -}
pipeLazy :: [CommandParam] -> (Handle -> IO ()) -> (Handle -> IO a) -> IO a
pipeLazy params feeder reader = do
params' <- stdParams $ Param "--batch" : params
withBothHandles createProcessSuccess (proc gpgcmd params')
$ \(to, from) -> do
void $ forkIO $ do
feeder to
hClose to
reader from
{- Finds gpg public keys matching some string. (Could be an email address,
- a key id, or a name; See the section 'HOW TO SPECIFY A USER ID' of
- GnuPG's manpage.) -}
findPubKeys :: String -> IO KeyIds
findPubKeys for = KeyIds . parse <$> readStrict params
where
params = [Params "--with-colons --list-public-keys", Param for]
parse = catMaybes . map (keyIdField . split ":") . lines
keyIdField ("pub":_:_:_:f:_) = Just f
keyIdField _ = Nothing
{- Creates a block of high-quality random data suitable to use as a cipher.
- It is armored, to avoid newlines, since gpg only reads ciphers up to the
- first newline. -}
genRandom :: Bool -> Int -> IO String
genRandom highQuality size = checksize <$> readStrict
[ Params params
, Param $ show randomquality
, Param $ show size
]
where
params = "--gen-random --armor"
-- See http://www.gnupg.org/documentation/manuals/gcrypt/Quality-of-random-numbers.html
-- for the meaning of random quality levels.
-- The highest available is 2, which is the default for OpenPGP
-- key generation; Note that it uses the blocking PRNG /dev/random
-- on the Linux kernel, hence the running time may take a while.
randomquality :: Int
randomquality = if highQuality then 2 else 1
{- The size is the number of bytes of entropy desired; the data is
- base64 encoded, so needs 8 bits to represent every 6 bytes of
- entropy. -}
expectedlength = size * 8 `div` 6
checksize s = let len = length s in
if len >= expectedlength
then s
else shortread len
shortread got = error $ unwords
[ "Not enough bytes returned from gpg", params
, "(got", show got, "; expected", show expectedlength, ")"
]
{- A test key. This is provided pre-generated since generating a new gpg
- key is too much work (requires too much entropy) for a test suite to
- do.
-
- This key was generated with no exipiration date, and a small keysize.
- It has an empty passphrase. -}
testKeyId :: String
testKeyId = "129D6E0AC537B9C7"
testKey :: String
testKey = keyBlock True
[ "mI0ETvFAZgEEAKnqwWgZqznMhi1RQExem2H8t3OyKDxaNN3rBN8T6LWGGqAYV4wT"
, "r8In5tfsnz64bKpE1Qi68JURFwYmthgUL9N48tbODU8t3xzijdjLOSaTyqkH1ik6"
, "EyulfKN63xLne9i4F9XqNwpiZzukXYbNfHkDA2yb0M6g4UFKLY/fNzGXABEBAAG0"
, "W2luc2VjdXJlIHRlc3Qga2V5ICh0aGlzIGlzIGEgdGVzdCBrZXksIGRvIG5vdCB1"
, "c2UgZm9yIGFjdHVhbCBlbmNyeXB0aW9uKSA8dGVzdEBleGFtcGxlLmNvbT6IuAQT"
, "AQgAIgUCTvFAZgIbAwYLCQgHAwIGFQgCCQoLBBYCAwECHgECF4AACgkQEp1uCsU3"
, "uceQ9wP/YMd1f0+/eLLcwGXNBvGqyVhUOfAKknO1bMzGbqTsq9g60qegy/cldqee"
, "xVxNfy0VN//JeMfgdcb8+RgJYLoaMrTy9CcsUcFPxtwN9tcLmsM0V2/fNmmFBO9t"
, "v75iH+zeFbNg0/FbPkHiN6Mjw7P2gXYKQXgTvQZBWaphk8oQlBm4jQRO8UBmAQQA"
, "vdi50M/WRCkOLt2RsUve8V8brMWYTJBJTTWoHUeRr82v4NCdX7OE1BsoVK8cy/1Q"
, "Y+gLOH9PqinuGGNWRmPV2Ju/RYn5H7sdewXA8E80xWhc4phHRMJ8Jjhg/GVPamkJ"
, "8B5zeKF0jcLFl7cuVdOyQakhoeDWJd0CyfW837nmPtMAEQEAAYifBBgBCAAJBQJO"
, "8UBmAhsMAAoJEBKdbgrFN7nHclAEAKBShuP/toH03atDUQTbGE34CA4yEC9BVghi"
, "7kviOZlOz2s8xAfp/8AYsrECx1kgbXcA7JD902eNyp7NzXsdJX0zJwHqiuZW0XlD"
, "T8ZJu4qrYRYgl/790WPESZ+ValvHD/fqkR38RF4tfxvyoMhhp0roGmJY33GASIG/"
, "+gQkDF9/"
, "=1k11"
]
testSecretKey :: String
testSecretKey = keyBlock False
[ "lQHYBE7xQGYBBACp6sFoGas5zIYtUUBMXpth/Ldzsig8WjTd6wTfE+i1hhqgGFeM"
, "E6/CJ+bX7J8+uGyqRNUIuvCVERcGJrYYFC/TePLWzg1PLd8c4o3Yyzkmk8qpB9Yp"
, "OhMrpXyjet8S53vYuBfV6jcKYmc7pF2GzXx5AwNsm9DOoOFBSi2P3zcxlwARAQAB"
, "AAP+PlRboxy7Z0XjuG70N6+CrzSddQbW5KCwgPFrxYsPk7sAPFcBkmRMVlv9vZpS"
, "phbP4bvDK+MrSntM51g+9uE802yhPhSWdmEbImiWfV2ucEhlLjD8gw7JDex9XZ0a"
, "EbTOV56wOsILuedX/jF/6i6IQzy5YmuMeo+ip1XQIsIN+80CAMyXepOBJgHw/gBD"
, "VdXh/l//vUkQQlhInQYwgkKbr0POCTdr8DM1qdKLcUD9Q1khgNRp0vZGGz+5xsrc"
, "KaODUlMCANSczLJcYWa8yPqB3S14yTe7qmtDiOS362+SeVUwQA7eQ06PcHLPsN+p"
, "NtWoHRfYazxrs+g0JvmoQOYdj4xSQy0CAMq7H/l6aeG1n8tpyMxqE7OvBOsvzdu5"
, "XS7I1AnwllVFgvTadVvqgf7b+hdYd91doeHDUGqSYO78UG1GgaBHJdylqrRbaW5z"
, "ZWN1cmUgdGVzdCBrZXkgKHRoaXMgaXMgYSB0ZXN0IGtleSwgZG8gbm90IHVzZSBm"
, "b3IgYWN0dWFsIGVuY3J5cHRpb24pIDx0ZXN0QGV4YW1wbGUuY29tPoi4BBMBCAAi"
, "BQJO8UBmAhsDBgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAAKCRASnW4KxTe5x5D3"
, "A/9gx3V/T794stzAZc0G8arJWFQ58AqSc7VszMZupOyr2DrSp6DL9yV2p57FXE1/"
, "LRU3/8l4x+B1xvz5GAlguhoytPL0JyxRwU/G3A321wuawzRXb982aYUE722/vmIf"
, "7N4Vs2DT8Vs+QeI3oyPDs/aBdgpBeBO9BkFZqmGTyhCUGZ0B2ARO8UBmAQQAvdi5"
, "0M/WRCkOLt2RsUve8V8brMWYTJBJTTWoHUeRr82v4NCdX7OE1BsoVK8cy/1QY+gL"
, "OH9PqinuGGNWRmPV2Ju/RYn5H7sdewXA8E80xWhc4phHRMJ8Jjhg/GVPamkJ8B5z"
, "eKF0jcLFl7cuVdOyQakhoeDWJd0CyfW837nmPtMAEQEAAQAD/RaVtFFTkF1udun7"
, "YOwzJvQXCO9OWHZvSdEeG4BUNdAwy4YWu0oZzKkBDBS6+lWILqqb/c28U4leUJ1l"
, "H+viz5svN9BWWyj/UpI00uwUo9JaIqalemwfLx6vsh69b54L1B4exLZHYGLvy/B3"
, "5T6bT0gpOE+53BRtKcJaOh/McQeJAgDTOCBU5weWOf6Bhqnw3Vr/gRfxntAz2okN"
, "gqz/h79mWbCc/lHKoYQSsrCdMiwziHSjXwvehUrdWE/AcomtW0vbAgDmGJqJ2fNr"
, "HvdsGx4Ld/BxyiZbCURJLUQ5CwzfHGIvBu9PMT8zM26NOSncaXRjxDna2Ggh8Uum"
, "ANEwbnhxFwZpAf9L9RLYIMTtAqwBjfXJg/lHcc2R+VP0hL5c8zFz+S+w7bRqINwL"
, "ff1JstKuHT2nJnu0ustK66by8YI3T0hDFFahnNCInwQYAQgACQUCTvFAZgIbDAAK"
, "CRASnW4KxTe5x3JQBACgUobj/7aB9N2rQ1EE2xhN+AgOMhAvQVYIYu5L4jmZTs9r"
, "PMQH6f/AGLKxAsdZIG13AOyQ/dNnjcqezc17HSV9MycB6ormVtF5Q0/GSbuKq2EW"
, "IJf+/dFjxEmflWpbxw/36pEd/EReLX8b8qDIYadK6BpiWN9xgEiBv/oEJAxffw=="
, "=LDsg"
]
keyBlock :: Bool -> [String] -> String
keyBlock public ls = unlines
[ "-----BEGIN PGP "++t++" KEY BLOCK-----"
, "Version: GnuPG v1.4.11 (GNU/Linux)"
, ""
, unlines ls
, "-----END PGP "++t++" KEY BLOCK-----"
]
where
t
| public = "PUBLIC"
| otherwise = "PRIVATE"
#ifndef mingw32_HOST_OS
{- Runs an action using gpg in a test harness, in which gpg does
- not use ~/.gpg/, but a directory with the test key set up to be used. -}
testHarness :: IO a -> IO a
testHarness a = do
orig <- getEnv var
bracket setup (cleanup orig) (const a)
where
var = "GNUPGHOME"
setup = do
base <- getTemporaryDirectory
dir <- mktmpdir $ base </> "gpgtmpXXXXXX"
void $ setEnv var dir True
_ <- pipeStrict [Params "--import -q"] $ unlines
[testSecretKey, testKey]
return dir
cleanup orig tmpdir = removeDirectoryRecursive tmpdir >> reset orig
reset (Just v) = setEnv var v True
reset _ = unsetEnv var
{- Tests the test harness. -}
testTestHarness :: IO Bool
testTestHarness = do
keys <- testHarness $ findPubKeys testKeyId
return $ KeyIds [testKeyId] == keys
#endif
#ifndef mingw32_HOST_OS
checkEncryptionFile :: FilePath -> Maybe KeyIds -> IO Bool
checkEncryptionFile filename keys =
checkGpgPackets keys =<< readStrict params
where
params = [Params "--list-packets --list-only", File filename]
checkEncryptionStream :: String -> Maybe KeyIds -> IO Bool
checkEncryptionStream stream keys =
checkGpgPackets keys =<< pipeStrict params stream
where
params = [Params "--list-packets --list-only"]
{- Parses an OpenPGP packet list, and checks whether data is
- symmetrically encrypted (keys is Nothing), or encrypted to some
- public key(s).
- /!\ The key needs to be in the keyring! -}
checkGpgPackets :: Maybe KeyIds -> String -> IO Bool
checkGpgPackets keys str = do
let (asym,sym) = partition (pubkeyEncPacket `isPrefixOf`) $
filter (\l' -> pubkeyEncPacket `isPrefixOf` l' ||
symkeyEncPacket `isPrefixOf` l') $
takeWhile (/= ":encrypted data packet:") $
lines str
case (keys,asym,sym) of
(Nothing, [], [_]) -> return True
(Just (KeyIds ks), ls, []) -> do
-- Find the master key associated with the
-- encryption subkey.
ks' <- concat <$> mapM (findPubKeys >=*> keyIds)
[ k | k:"keyid":_ <- map (reverse . words) ls ]
return $ sort (nub ks) == sort (nub ks')
_ -> return False
where
pubkeyEncPacket = ":pubkey enc packet: "
symkeyEncPacket = ":symkey enc packet: "
#endif