git-annex/Remote/S3.hs
Joey Hess 2f3c3aa01f glacier, S3: Fix bug that caused embedded creds to not be encypted using the remote's key.
encryptionSetup must be called before setRemoteCredPair. Otherwise,
the RemoteConfig doesn't have the cipher in it, and so no cipher is used to
encrypt the embedded creds.

This is a security fix for non-shared encryption methods!

For encryption=shared, there's no security problem, just an
inconsistentency in whether the embedded creds are encrypted.

This is very important to get right, so used some types to help ensure that
setRemoteCredPair is only run after encryptionSetup. Note that the external
special remote bypasses the type safety, since creds can be set after the
initial remote config, if the external special remote program requests it.
Also note that IA remotes never use encryption, so encryptionSetup is not
run for them at all, and again the type safety is bypassed.

This leaves two open questions:

1. What to do about S3 and glacier remotes that were set up
   using encryption=pubkey/hybrid with embedcreds?
   Such a git repo has a security hole embedded in it, and this needs to be
   communicated to the user. Is the changelog enough?

2. enableremote won't work in such a repo, because git-annex will
   try to decrypt the embedded creds, which are not encrypted, so fails.
   This needs to be dealt with, especially for ecryption=shared repos,
   which are not really broken, just inconsistently configured.

   Noticing that problem for encryption=shared is what led to commit
   fbdeeeed5f, which tried to
   fix the problem by not decrypting the embedded creds.

This commit was sponsored by Josh Taylor.
2014-09-18 17:26:12 -04:00

345 lines
11 KiB
Haskell

{- S3 remotes
-
- Copyright 2011-2013 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Remote.S3 (remote, iaHost, isIA, isIAHost, iaItemUrl) where
import Network.AWS.AWSConnection
import Network.AWS.S3Object hiding (getStorageClass)
import Network.AWS.S3Bucket hiding (size)
import Network.AWS.AWSResult
import qualified Data.Text as T
import qualified Data.Text.Encoding as T
import qualified Data.ByteString.Lazy as L
import qualified Data.Map as M
import Data.Char
import Network.Socket (HostName)
import Common.Annex
import Types.Remote
import Types.Key
import qualified Git
import Config
import Config.Cost
import Remote.Helper.Special
import qualified Remote.Helper.AWS as AWS
import Creds
import Utility.Metered
import Annex.UUID
import Logs.Web
type Bucket = String
remote :: RemoteType
remote = RemoteType {
typename = "S3",
enumerate = findSpecialRemotes "s3",
generate = gen,
setup = s3Setup
}
gen :: Git.Repo -> UUID -> RemoteConfig -> RemoteGitConfig -> Annex (Maybe Remote)
gen r u c gc = new <$> remoteCost gc expensiveRemoteCost
where
new cst = Just $ specialRemote c
(prepareStore this)
(prepareRetrieve this)
(simplyPrepare $ remove this c)
(simplyPrepare $ checkKey this)
this
where
this = Remote {
uuid = u,
cost = cst,
name = Git.repoDescribe r,
storeKey = storeKeyDummy,
retrieveKeyFile = retreiveKeyFileDummy,
retrieveKeyFileCheap = retrieveCheap,
removeKey = removeKeyDummy,
checkPresent = checkPresentDummy,
checkPresentCheap = False,
whereisKey = Nothing,
remoteFsck = Nothing,
repairRepo = Nothing,
config = c,
repo = r,
gitconfig = gc,
localpath = Nothing,
readonly = False,
availability = GloballyAvailable,
remotetype = remote,
mkUnavailable = gen r u (M.insert "host" "!dne!" c) gc
}
s3Setup :: Maybe UUID -> Maybe CredPair -> RemoteConfig -> Annex (RemoteConfig, UUID)
s3Setup mu mcreds c = do
u <- maybe (liftIO genUUID) return mu
s3Setup' u mcreds c
s3Setup' :: UUID -> Maybe CredPair -> RemoteConfig -> Annex (RemoteConfig, UUID)
s3Setup' u mcreds c = if isIA c then archiveorg else defaulthost
where
remotename = fromJust (M.lookup "name" c)
defbucket = remotename ++ "-" ++ fromUUID u
defaults = M.fromList
[ ("datacenter", T.unpack $ AWS.defaultRegion AWS.S3)
, ("storageclass", "STANDARD")
, ("host", defaultAmazonS3Host)
, ("port", show defaultAmazonS3Port)
, ("bucket", defbucket)
]
use fullconfig = do
gitConfigSpecialRemote u fullconfig "s3" "true"
return (fullconfig, u)
defaulthost = do
(c', encsetup) <- encryptionSetup c
c'' <- setRemoteCredPair encsetup c' (AWS.creds u) mcreds
let fullconfig = c'' `M.union` defaults
genBucket fullconfig u
use fullconfig
archiveorg = do
showNote "Internet Archive mode"
void $ setRemoteCredPair noEncryptionUsed c (AWS.creds u) mcreds
-- Ensure user enters a valid bucket name, since
-- this determines the name of the archive.org item.
let bucket = replace " " "-" $ map toLower $
fromMaybe (error "specify bucket=") $
getBucket c
let archiveconfig =
-- hS3 does not pass through x-archive-* headers
M.mapKeys (replace "x-archive-" "x-amz-") $
-- encryption does not make sense here
M.insert "encryption" "none" $
M.insert "bucket" bucket $
M.union c $
-- special constraints on key names
M.insert "mungekeys" "ia" $
-- bucket created only when files are uploaded
M.insert "x-amz-auto-make-bucket" "1" defaults
writeUUIDFile archiveconfig u
use archiveconfig
prepareStore :: Remote -> Preparer Storer
prepareStore r = resourcePrepare (const $ s3Action r False) $ \(conn, bucket) ->
fileStorer $ \k src p -> do
ok <- s3Bool =<< liftIO (store (conn, bucket) r k p src)
-- Store public URL to item in Internet Archive.
when (ok && isIA (config r) && not (isChunkKey k)) $
setUrlPresent k (iaKeyUrl r k)
return ok
store :: (AWSConnection, Bucket) -> Remote -> Key -> MeterUpdate -> FilePath -> IO (AWSResult ())
store (conn, bucket) r k p file = do
size <- (fromIntegral . fileSize <$> getFileStatus file) :: IO Integer
withMeteredFile file p $ \content -> do
-- size is provided to S3 so the whole content
-- does not need to be buffered to calculate it
let object = S3Object
bucket (bucketFile r k) ""
(("Content-Length", show size) : getXheaders (config r))
content
sendObject conn $
setStorageClass (getStorageClass $ config r) object
prepareRetrieve :: Remote -> Preparer Retriever
prepareRetrieve r = resourcePrepare (const $ s3Action r False) $ \(conn, bucket) ->
byteRetriever $ \k sink ->
liftIO (getObject conn $ bucketKey r bucket k)
>>= either s3Error (sink . obj_data)
retrieveCheap :: Key -> FilePath -> Annex Bool
retrieveCheap _ _ = return False
{- Internet Archive doesn't easily allow removing content.
- While it may remove the file, there are generally other files
- derived from it that it does not remove. -}
remove :: Remote -> RemoteConfig -> Remover
remove r c k
| isIA c = do
warning "Cannot remove content from the Internet Archive"
return False
| otherwise = remove' r k
remove' :: Remote -> Key -> Annex Bool
remove' r k = s3Action r False $ \(conn, bucket) ->
s3Bool =<< liftIO (deleteObject conn $ bucketKey r bucket k)
checkKey :: Remote -> CheckPresent
checkKey r k = s3Action r noconn $ \(conn, bucket) -> do
showAction $ "checking " ++ name r
res <- liftIO $ getObjectInfo conn $ bucketKey r bucket k
case res of
Right _ -> return True
Left (AWSError _ _) -> return False
Left e -> s3Error e
where
noconn = error "S3 not configured"
s3Warning :: ReqError -> Annex Bool
s3Warning e = do
warning $ prettyReqError e
return False
s3Error :: ReqError -> a
s3Error e = error $ prettyReqError e
s3Bool :: AWSResult () -> Annex Bool
s3Bool (Right _) = return True
s3Bool (Left e) = s3Warning e
s3Action :: Remote -> a -> ((AWSConnection, Bucket) -> Annex a) -> Annex a
s3Action r noconn action = do
let bucket = M.lookup "bucket" $ config r
conn <- s3Connection (config r) (uuid r)
case (bucket, conn) of
(Just b, Just c) -> action (c, b)
_ -> return noconn
bucketFile :: Remote -> Key -> FilePath
bucketFile r = munge . key2file
where
munge s = case M.lookup "mungekeys" c of
Just "ia" -> iaMunge $ filePrefix c ++ s
_ -> filePrefix c ++ s
c = config r
filePrefix :: RemoteConfig -> String
filePrefix = M.findWithDefault "" "fileprefix"
bucketKey :: Remote -> Bucket -> Key -> S3Object
bucketKey r bucket k = S3Object bucket (bucketFile r k) "" [] L.empty
{- Internet Archive limits filenames to a subset of ascii,
- with no whitespace. Other characters are xml entity
- encoded. -}
iaMunge :: String -> String
iaMunge = (>>= munge)
where
munge c
| isAsciiUpper c || isAsciiLower c || isNumber c = [c]
| c `elem` "_-.\"" = [c]
| isSpace c = []
| otherwise = "&" ++ show (ord c) ++ ";"
{- Generate the bucket if it does not already exist, including creating the
- UUID file within the bucket.
-
- To check if the bucket exists, ask for its location. However, some ACLs
- can allow read/write to buckets, but not querying location, so first
- check if the UUID file already exists and we can skip doing anything.
-}
genBucket :: RemoteConfig -> UUID -> Annex ()
genBucket c u = do
conn <- s3ConnectionRequired c u
showAction "checking bucket"
unlessM ((== Right True) <$> checkUUIDFile c u conn) $ do
loc <- liftIO $ getBucketLocation conn bucket
case loc of
Right _ -> writeUUIDFile c u
Left err@(NetworkError _) -> s3Error err
Left (AWSError _ _) -> do
showAction $ "creating bucket in " ++ datacenter
res <- liftIO $ createBucketIn conn bucket datacenter
case res of
Right _ -> writeUUIDFile c u
Left err -> s3Error err
where
bucket = fromJust $ getBucket c
datacenter = fromJust $ M.lookup "datacenter" c
{- Writes the UUID to an annex-uuid file within the bucket.
-
- If the file already exists in the bucket, it must match.
-
- Note that IA items do not get created by createBucketIn.
- Rather, they are created the first time a file is stored in them.
- So this also takes care of that.
-}
writeUUIDFile :: RemoteConfig -> UUID -> Annex ()
writeUUIDFile c u = do
conn <- s3ConnectionRequired c u
v <- checkUUIDFile c u conn
case v of
Left e -> error e
Right True -> return ()
Right False -> do
let object = setStorageClass (getStorageClass c) (mkobject uuidb)
either s3Error return =<< liftIO (sendObject conn object)
where
file = uuidFile c
uuidb = L.fromChunks [T.encodeUtf8 $ T.pack $ fromUUID u]
bucket = fromJust $ getBucket c
mkobject = S3Object bucket file "" (getXheaders c)
{- Checks if the UUID file exists in the bucket and has the specified UUID already. -}
checkUUIDFile :: RemoteConfig -> UUID -> AWSConnection -> Annex (Either String Bool)
checkUUIDFile c u conn = check <$> liftIO (tryNonAsync $ getObject conn $ mkobject L.empty)
where
check (Right (Right o))
| obj_data o == uuidb = Right True
| otherwise = Left $ "This bucket is already in use by a different S3 special remote, with UUID: " ++ show (obj_data o)
check _ = Right False
uuidb = L.fromChunks [T.encodeUtf8 $ T.pack $ fromUUID u]
bucket = fromJust $ getBucket c
file = uuidFile c
mkobject = S3Object bucket file "" (getXheaders c)
uuidFile :: RemoteConfig -> FilePath
uuidFile c = filePrefix c ++ "annex-uuid"
s3ConnectionRequired :: RemoteConfig -> UUID -> Annex AWSConnection
s3ConnectionRequired c u =
maybe (error "Cannot connect to S3") return =<< s3Connection c u
s3Connection :: RemoteConfig -> UUID -> Annex (Maybe AWSConnection)
s3Connection c u = go =<< getRemoteCredPairFor "S3" c (AWS.creds u)
where
go Nothing = return Nothing
go (Just (ak, sk)) = return $ Just $ AWSConnection host port ak sk
host = fromJust $ M.lookup "host" c
port = let s = fromJust $ M.lookup "port" c in
case reads s of
[(p, _)] -> p
_ -> error $ "bad S3 port value: " ++ s
getBucket :: RemoteConfig -> Maybe Bucket
getBucket = M.lookup "bucket"
getStorageClass :: RemoteConfig -> StorageClass
getStorageClass c = case fromJust $ M.lookup "storageclass" c of
"REDUCED_REDUNDANCY" -> REDUCED_REDUNDANCY
_ -> STANDARD
getXheaders :: RemoteConfig -> [(String, String)]
getXheaders = filter isxheader . M.assocs
where
isxheader (h, _) = "x-amz-" `isPrefixOf` h
{- Hostname to use for archive.org S3. -}
iaHost :: HostName
iaHost = "s3.us.archive.org"
isIA :: RemoteConfig -> Bool
isIA c = maybe False isIAHost (M.lookup "host" c)
isIAHost :: HostName -> Bool
isIAHost h = ".archive.org" `isSuffixOf` map toLower h
iaItemUrl :: Bucket -> URLString
iaItemUrl bucket = "http://archive.org/details/" ++ bucket
iaKeyUrl :: Remote -> Key -> URLString
iaKeyUrl r k = "http://archive.org/download/" ++ bucket ++ "/" ++ bucketFile r k
where
bucket = fromMaybe "" $ getBucket $ config r