git-annex/Utility/Gpg.hs
Joey Hess c41ca6c832
convert StorableCipher to ByteString
This allows getting rid of the ugly and error prone handling of
"bag of bytes" String in Remote.Helper.Encryptable.
Avoiding breakage like that dealt with by commit
9862d64bf9

And allows converting Utility.Gpg to use ByteString for IO, which is
a welcome change.

Tested the new git-annex interoperability with old, using all 3
encryption= types.

Sponsored-By: the NIH-funded NICEMAN (ReproNim TR&D3) project
2023-11-01 14:39:49 -04:00

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{- gpg interface
-
- Copyright 2011-2023 Joey Hess <id@joeyh.name>
-
- License: BSD-2-clause
-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE CPP #-}
module Utility.Gpg (
KeyId,
KeyIds(..),
GpgCmd(..),
mkGpgCmd,
boolGpgCmd,
pkEncTo,
stdEncryptionParams,
pipeStrict,
pipeStrict',
feedRead,
feedRead',
findPubKeys,
UserId,
secretKeys,
KeyType(..),
maxRecommendedKeySize,
genSecretKey,
genRandom,
testKeyId,
#ifndef mingw32_HOST_OS
testHarness,
checkEncryptionFile,
checkEncryptionStream,
#endif
) where
import Common
import qualified BuildInfo
#ifndef mingw32_HOST_OS
import System.Posix.Types
import System.Posix.IO
import Utility.Env
import Utility.FileMode
#else
import Utility.Tmp
#endif
import Utility.Format (decode_c)
import Control.Concurrent.Async
import Control.Monad.IO.Class
import qualified Data.ByteString as B
import qualified Data.Map as M
import Data.Char
type KeyId = String
newtype KeyIds = KeyIds { keyIds :: [KeyId] }
deriving (Ord, Eq)
newtype GpgCmd = GpgCmd { unGpgCmd :: String }
{- Get gpg command to use, Just what's specified or, if a specific gpg
- command was found at configure time, use it, or otherwise, "gpg". -}
mkGpgCmd :: Maybe FilePath -> GpgCmd
mkGpgCmd (Just c) = GpgCmd c
mkGpgCmd Nothing = GpgCmd (fromMaybe "gpg" BuildInfo.gpg)
boolGpgCmd :: GpgCmd -> [CommandParam] -> IO Bool
boolGpgCmd (GpgCmd cmd) = boolSystem cmd
-- 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 =
[ Param "--encrypt"
, Param "--no-encrypt-to"
, Param "--no-default-recipient"
]
{- Runs gpg with some params and returns its stdout, strictly. -}
readStrict :: GpgCmd -> [CommandParam] -> IO B.ByteString
readStrict c p = readStrict' c p Nothing
readStrict' :: GpgCmd -> [CommandParam] -> Maybe [(String, String)] -> IO B.ByteString
readStrict' (GpgCmd cmd) params environ = do
params' <- stdParams params
let p = (proc cmd params')
{ std_out = CreatePipe
, env = environ
}
withCreateProcess p (go p)
where
go p _ (Just hout) _ pid =
forceSuccessProcess p pid `after` B.hGetContents hout
go _ _ _ _ _ = error "internal"
{- Runs gpg, piping an input value to it, and returning its stdout,
- strictly. -}
pipeStrict :: GpgCmd -> [CommandParam] -> B.ByteString -> IO B.ByteString
pipeStrict c p i = pipeStrict' c p Nothing i
pipeStrict' :: GpgCmd -> [CommandParam] -> Maybe [(String, String)] -> B.ByteString -> IO B.ByteString
pipeStrict' (GpgCmd cmd) params environ input = do
params' <- stdParams params
let p = (proc cmd params')
{ std_in = CreatePipe
, std_out = CreatePipe
, env = environ
}
withCreateProcess p (go p)
where
go p (Just to) (Just from) _ pid = do
B.hPutStr to input
hClose to
forceSuccessProcess p pid `after` B.hGetContents from
go _ _ _ _ _ = error "internal"
{- 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 the reader must fully consume gpg's input before returning. -}
feedRead :: (MonadIO m, MonadMask m) => GpgCmd -> [CommandParam] -> B.ByteString -> (Handle -> IO ()) -> (Handle -> m a) -> m a
feedRead cmd params passphrase feeder reader = do
#ifndef mingw32_HOST_OS
let setup = liftIO $ do
-- pipe the passphrase into gpg on a fd
(frompipe, topipe) <- System.Posix.IO.createPipe
toh <- fdToHandle topipe
t <- async $ do
B.hPutStr toh (passphrase <> "\n")
hClose toh
let Fd pfd = frompipe
let passphrasefd = [Param "--passphrase-fd", Param $ show pfd]
return (passphrasefd, frompipe, toh, t)
let cleanup (_, frompipe, toh, t) = liftIO $ do
closeFd frompipe
hClose toh
cancel t
bracket setup cleanup $ \(passphrasefd, _, _, _) ->
go (passphrasefd ++ params)
#else
-- store the passphrase in a temp file for gpg
withTmpFile "gpg" $ \tmpfile h -> do
liftIO $ B.hPutStr h passphrase
liftIO $ hClose h
let passphrasefile = [Param "--passphrase-file", File tmpfile]
go $ passphrasefile ++ params
#endif
where
go params' = feedRead' cmd params' feeder reader
{- Like feedRead, but without passphrase. -}
feedRead' :: (MonadIO m, MonadMask m) => GpgCmd -> [CommandParam] -> (Handle -> IO ()) -> (Handle -> m a) -> m a
feedRead' (GpgCmd cmd) params feeder reader = do
params' <- liftIO $ stdParams $ Param "--batch" : params
let p = (proc cmd params')
{ std_in = CreatePipe
, std_out = CreatePipe
, std_err = Inherit
}
bracket (setup p) cleanup (go p)
where
setup = liftIO . createProcess
cleanup = liftIO . cleanupProcess
go p (Just to, Just from, _, pid) =
let runfeeder = do
feeder to
hClose to
in bracketIO (async runfeeder) cancel $ const $ do
r <- reader from
liftIO $ forceSuccessProcess p pid
return r
go _ _ = error "internal"
{- 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 :: GpgCmd -> String -> IO KeyIds
findPubKeys cmd = findPubKeys' cmd Nothing
findPubKeys' :: GpgCmd -> Maybe [(String, String)] -> String -> IO KeyIds
findPubKeys' cmd environ for
-- pass forced subkey through as-is rather than
-- looking up the master key.
| isForcedSubKey for = return $ KeyIds [for]
| otherwise = KeyIds . parse . lines . decodeBS
<$> readStrict' cmd params environ
where
params = [Param "--with-colons", Param "--list-public-keys", Param for]
parse = mapMaybe (keyIdField . splitc ':')
keyIdField ("pub":_:_:_:f:_) = Just f
keyIdField _ = Nothing
{- "subkey!" tells gpg to force use of a specific subkey -}
isForcedSubKey :: String -> Bool
isForcedSubKey s = "!" `isSuffixOf` s && all isHexDigit (drop 1 (reverse s))
type UserId = String
{- All of the user's secret keys, with their UserIds.
- Note that the UserId may be empty. -}
secretKeys :: GpgCmd -> IO (M.Map KeyId UserId)
secretKeys cmd = catchDefaultIO M.empty makemap
where
makemap = M.fromList . parse . lines . decodeBS
<$> readStrict cmd params
params = [Param "--with-colons", Param "--list-secret-keys", Param "--fixed-list-mode"]
parse = extract [] Nothing . map (splitc ':')
extract c (Just keyid) (("uid":_:_:_:_:_:_:_:_:userid:_):rest) =
-- If the userid contains a ":" or a few other special
-- characters, gpg will hex-escape it. Use decode_c to
-- undo.
extract ((keyid, decodeBS (decode_c (encodeBS userid))):c) Nothing rest
extract c (Just keyid) rest@(("sec":_):_) =
extract ((keyid, ""):c) Nothing rest
extract c (Just keyid) (_:rest) =
extract c (Just keyid) 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 :: GpgCmd -> KeyType -> Passphrase -> UserId -> Size -> IO ()
genSecretKey (GpgCmd cmd) keytype passphrase userid keysize =
let p = (proc cmd params)
{ std_in = CreatePipe }
in withCreateProcess p (go p)
where
params = ["--batch", "--gen-key"]
go p (Just h) _ _ pid = 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
forceSuccessProcess p pid
go _ _ _ _ _ = error "internal"
{- 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 :: GpgCmd -> Bool -> Size -> IO B.ByteString
genRandom cmd highQuality size = do
s <- readStrict cmd params
checksize s
return s
where
params =
[ Param "--gen-random"
, Param "--armor"
, Param $ show randomquality
, Param $ show size
]
-- 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 = B.length s in
unless (len >= expectedlength) $
shortread len
shortread got = giveup $ unwords
[ "Not enough bytes returned from gpg", show 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"
#ifndef mingw32_HOST_OS
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"
{- Runs an action using gpg in a test harness, in which gpg does
- not use ~/.gpg/, but sets up the test key in a subdirectory of
- the passed directory and uses it.
-
- If the test harness is not able to be set up (eg, because gpg is not
- installed or because there is some problem importing the test key,
- perhaps related to the agent socket), the action is not run, and Nothing
- is returned.
-}
testHarness :: FilePath -> GpgCmd -> ([(String, String)] -> IO a) -> IO (Maybe a)
testHarness tmpdir cmd a = ifM (inSearchPath (unGpgCmd cmd))
( bracket (eitherToMaybe <$> tryNonAsync setup) cleanup go
, return Nothing
)
where
var = "GNUPGHOME"
setup = do
subdir <- makenewdir (1 :: Integer)
origenviron <- getEnvironment
let environ = addEntry var subdir origenviron
-- gpg is picky about permissions on its home dir
liftIO $ void $ tryIO $ modifyFileMode (toRawFilePath subdir) $
removeModes $ otherGroupModes
-- For some reason, recent gpg needs a trustdb to be set up.
_ <- pipeStrict' cmd [Param "--trust-model", Param "auto", Param "--update-trustdb"] (Just environ) mempty
_ <- pipeStrict' cmd [Param "--import", Param "-q"] (Just environ) $ encodeBS $ unlines
[testSecretKey, testKey]
return environ
cleanup Nothing = return ()
cleanup (Just environ) = stopgpgagent environ
-- Recent versions of gpg automatically start gpg-agent, or perhaps
-- other daemons. Stop them when done. This only affects
-- daemons started for the GNUPGHOME that was used.
-- Older gpg may not support this, so ignore failure.
stopgpgagent environ = whenM (inSearchPath "gpgconf") $
void $ boolSystemEnv "gpgconf" [Param "--kill", Param "all"]
(Just environ)
go (Just environ) = Just <$> a environ
go Nothing = return Nothing
makenewdir n = do
let subdir = tmpdir </> show n
catchIOErrorType AlreadyExists (const $ makenewdir $ n + 1) $ do
createDirectory subdir
return subdir
checkEncryptionFile :: GpgCmd -> Maybe [(String, String)] -> FilePath -> Maybe KeyIds -> IO Bool
checkEncryptionFile cmd environ filename keys =
checkGpgPackets cmd environ keys =<< readStrict' cmd params environ
where
params = [Param "--list-packets", Param "--list-only", File filename]
checkEncryptionStream :: GpgCmd -> Maybe [(String, String)] -> B.ByteString -> Maybe KeyIds -> IO Bool
checkEncryptionStream cmd environ stream keys =
checkGpgPackets cmd environ keys =<< pipeStrict' cmd params environ stream
where
params = [Param "--list-packets", Param "--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 :: GpgCmd -> Maybe [(String, String)] -> Maybe KeyIds -> B.ByteString -> IO Bool
checkGpgPackets cmd environ keys str = do
let (asym,sym) = partition (pubkeyEncPacket `isPrefixOf`) $
filter (\l' -> pubkeyEncPacket `isPrefixOf` l' ||
symkeyEncPacket `isPrefixOf` l') $
takeWhile (/= ":encrypted data packet:") $
lines (decodeBS 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' cmd environ)
[ 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