diff options
Diffstat (limited to 'Backend/SHA.hs')
| -rw-r--r-- | Backend/SHA.hs | 24 |
1 files changed, 22 insertions, 2 deletions
diff --git a/Backend/SHA.hs b/Backend/SHA.hs index 77bd2c124..258caafd1 100644 --- a/Backend/SHA.hs +++ b/Backend/SHA.hs @@ -57,8 +57,9 @@ shaN shasize file filesize = do showAction "checksum" case shaCommand shasize filesize of Left sha -> liftIO $ sha <$> L.readFile file - Right command -> liftIO $ parse command . lines <$> - readsha command (toCommand [File file]) + Right command -> liftIO $ + sanitycheck command . parse command . lines <$> + readsha command (toCommand [File file]) where parse command [] = bad command parse command (l:_) @@ -69,6 +70,7 @@ shaN shasize file filesize = do where sha = fst $ separate (== ' ') l bad command = error $ command ++ " parse error" + {- sha commands output the filename, so need to set fileEncoding -} readsha command args = withHandle StdoutHandle createProcessSuccess p $ \h -> do @@ -79,6 +81,24 @@ shaN shasize file filesize = do where p = (proc command args) { std_out = CreatePipe } + {- Check that we've correctly parsing the output of the command, + - by making sure the sha we read is of the expected length. -} + sanitycheck command sha + | length sha /= expectedlen = + error $ "Failed to parse the output of " ++ command + | any (`notElem` "0123456789abcdef") sha' = + error $ "Unexpected character in output of " ++ command ++ "\"" ++ sha ++ "\"" + | otherwise = sha' + where + sha' = map toLower sha + expectedlen = case shasize of + 1 -> 40 + 256 -> 64 + 512 -> 128 + 224 -> 56 + 384 -> 96 + _ -> 0 + shaCommand :: SHASize -> Integer -> Either (L.ByteString -> String) String shaCommand shasize filesize | shasize == 1 = use SysConfig.sha1 sha1 |