git-annex/Utility/Gpg.hs
Joey Hess 1e59df083d Use haskell setenv library to clean up several ugly workarounds for inability to manipulate the environment on windows.
Didn't know that this library existed!

This includes making git-annex not re-exec itself on start on windows, and
making the test suite on Windows run tests without forking.
2014-10-15 20:33:52 -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 Control.Monad.IO.Class
import qualified Data.Map as M
import Common
import qualified Build.SysConfig as SysConfig
#ifndef mingw32_HOST_OS
import System.Posix.Types
import System.Path
import Utility.Env
#else
import Utility.Tmp
#endif
import Utility.Format (decode_c)
type KeyId = String
newtype KeyIds = KeyIds { keyIds :: [KeyId] }
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.
defaults = ["--quiet", "--trust-model", "always"]
{- Usual options for symmetric / public-key encryption. -}
stdEncryptionParams :: Bool -> [CommandParam]
stdEncryptionParams symmetric =
[ enc symmetric
, Param "--force-mdc"
, Param "--no-textmode"
]
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 :: (MonadIO m, MonadMask m) => [CommandParam] -> String -> (Handle -> IO ()) -> (Handle -> m a) -> m a
feedRead params passphrase feeder reader = do
#ifndef mingw32_HOST_OS
-- pipe the passphrase into gpg on a fd
(frompipe, topipe) <- liftIO createPipe
liftIO $ void $ forkIO $ do
toh <- fdToHandle topipe
hPutStrLn toh passphrase
hClose toh
let Fd pfd = frompipe
let passphrasefd = [Param "--passphrase-fd", Param $ show pfd]
liftIO (closeFd frompipe) `after` go (passphrasefd ++ params)
#else
-- store the passphrase in a temp file for gpg
withTmpFile "gpg" $ \tmpfile h -> do
liftIO $ hPutStr h passphrase
liftIO $ 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 :: (MonadIO m, MonadMask m) => [CommandParam] -> (Handle -> IO ()) -> (Handle -> m a) -> m a
pipeLazy params feeder reader = do
params' <- liftIO $ stdParams $ Param "--batch" : params
let p = (proc gpgcmd params')
{ std_in = CreatePipe
, std_out = CreatePipe
, std_err = Inherit
}
bracket (setup p) (cleanup p) go
where
setup = liftIO . createProcess
cleanup p (_, _, _, pid) = liftIO $ forceSuccessProcess p pid
go p = do
let (to, from) = bothHandles p
liftIO $ 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 . lines <$> readStrict params
where
params = [Params "--with-colons --list-public-keys", Param for]
parse = mapMaybe (keyIdField . split ":")
keyIdField ("pub":_:_:_:f:_) = Just f
keyIdField _ = Nothing
type UserId = String
{- All of the user's secret keys, with their UserIds.
- Note that the UserId may be empty. -}
secretKeys :: IO (M.Map KeyId UserId)
secretKeys = catchDefaultIO M.empty makemap
where
makemap = M.fromList . parse . lines <$> readStrict params
params = [Params "--with-colons --list-secret-keys --fixed-list-mode"]
parse = extract [] Nothing . map (split ":")
extract c (Just keyid) (("uid":_:_:_:_:_:_:_:_:userid:_):rest) =
extract ((keyid, decode_c userid):c) Nothing rest
extract c (Just keyid) rest =
extract ((keyid, ""):c) Nothing rest
extract c _ [] = c
extract c _ (("sec":_:_:_:keyid:_):rest) =
extract c (Just keyid) rest
extract c k (_:rest) =
extract c k rest
type Passphrase = String
type Size = Int
data KeyType = Algo Int | DSA | RSA
{- The maximum key size that gpg currently offers in its UI when
- making keys. -}
maxRecommendedKeySize :: Size
maxRecommendedKeySize = 4096
{- Generates a secret key using the experimental batch mode.
- The key is added to the secret key ring.
- Can take a very long time, depending on system entropy levels.
-}
genSecretKey :: KeyType -> Passphrase -> UserId -> Size -> IO ()
genSecretKey keytype passphrase userid keysize =
withHandle StdinHandle createProcessSuccess (proc gpgcmd params) feeder
where
params = ["--batch", "--gen-key"]
feeder h = do
hPutStr h $ unlines $ catMaybes
[ Just $ "Key-Type: " ++
case keytype of
DSA -> "DSA"
RSA -> "RSA"
Algo n -> show n
, Just $ "Key-Length: " ++ show keysize
, Just $ "Name-Real: " ++ userid
, Just "Expire-Date: 0"
, if null passphrase
then Nothing
else Just $ "Passphrase: " ++ passphrase
]
hClose h
{- 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 -> Size -> 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"
setEnv var dir True
-- For some reason, recent gpg needs a trustdb to be set up.
_ <- pipeStrict [Params "--trust-model auto --update-trustdb"] []
_ <- 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 (keyIds <$$> findPubKeys)
[ 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