git-annex/Git/CheckAttr.hs
Joey Hess cd544e548b
filter out control characters in error messages
giveup changed to filter out control characters. (It is too low level to
make it use StringContainingQuotedPath.)

error still does not, but it should only be used for internal errors,
where the message is not attacker-controlled.

Changed a lot of existing error to giveup when it is not strictly an
internal error.

Of course, other exceptions can still be thrown, either by code in
git-annex, or a library, that include some attacker-controlled value.
This does not guard against those.

Sponsored-by: Noam Kremen on Patreon
2023-04-10 13:50:51 -04:00

101 lines
3 KiB
Haskell

{- git check-attr interface
-
- Copyright 2010-2021 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module Git.CheckAttr where
import Common
import Git
import Git.Command
import qualified Utility.CoProcess as CoProcess
import qualified Utility.RawFilePath as R
import System.IO.Error
import qualified Data.ByteString as B
type CheckAttrHandle = (CoProcess.CoProcessHandle, [Attr], RawFilePath)
type Attr = String
{- Starts git check-attr running to look up the specified attributes
- and returns a handle. -}
checkAttrStart :: [Attr] -> Repo -> IO CheckAttrHandle
checkAttrStart attrs repo = do
currdir <- R.getCurrentDirectory
h <- gitCoProcessStart True params repo
return (h, attrs, currdir)
where
params =
[ Param "check-attr"
, Param "-z"
, Param "--stdin"
] ++ map Param attrs ++
[ Param "--" ]
checkAttrStop :: CheckAttrHandle -> IO ()
checkAttrStop (h, _, _) = CoProcess.stop h
checkAttr :: CheckAttrHandle -> Attr -> RawFilePath -> IO String
checkAttr h want file = checkAttrs h [want] file >>= return . \case
(v:_) -> v
[] -> ""
{- Gets attributes of a file. When an attribute is not specified,
- returns "" for it. -}
checkAttrs :: CheckAttrHandle -> [Attr] -> RawFilePath -> IO [String]
checkAttrs (h, attrs, currdir) want file = do
l <- CoProcess.query h send (receive "")
return (getvals l want)
where
getvals _ [] = []
getvals l (x:xs) = case map snd $ filter (\(attr, _) -> attr == x) l of
["unspecified"] -> "" : getvals l xs
[v] -> v : getvals l xs
_ -> giveup $ "unable to determine " ++ x ++ " attribute of " ++ fromRawFilePath file
send to = B.hPutStr to $ file' `B.snoc` 0
receive c from = do
s <- hGetSomeString from 1024
if null s
then eofError
else do
let v = c ++ s
maybe (receive v from) return (parse v)
eofError = ioError $ mkIOError userErrorType "git check-attr EOF" Nothing Nothing
parse s
-- new null separated output
| '\0' `elem` s = if "\0" `isSuffixOf` s
then
let bits = segment (== '\0') s
in if length bits == (numattrs * 3) + 1
then Just $ getattrvalues bits []
else Nothing -- more attributes to come
else Nothing -- output incomplete
-- old one line per value output
| otherwise = if "\n" `isSuffixOf` s
then
let ls = lines s
in if length ls == numattrs
then Just $ map (\(attr, val) -> (attr, oldattrvalue attr val))
(zip attrs ls)
else Nothing -- more attributes to come
else Nothing -- line incomplete
numattrs = length attrs
{- git check-attr chokes on some absolute filenames,
- so make sure the filename is relative. -}
file' = relPathDirToFileAbs currdir $ absPathFrom currdir file
oldattrvalue attr l = end bits !! 0
where
bits = split sep l
sep = ": " ++ attr ++ ": "
getattrvalues (_filename:attr:val:rest) c = getattrvalues rest ((attr,val):c)
getattrvalues _ c = c
{- User may enter this to override a previous attr setting, when they wish
- to not specify an attr for some files. -}
unspecifiedAttr :: String
unspecifiedAttr = "!"