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-rw-r--r--Backend/SHA.hs24
-rw-r--r--debian/changelog2
2 files changed, 24 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
diff --git a/debian/changelog b/debian/changelog
index 3c268866d..38e276b1d 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -15,6 +15,8 @@ git-annex (4.20130502) UNRELEASED; urgency=low
* git-annex-shell: Ensure that received files can be read. Files
transferred from some Android devices may have very broken permissions
as received.
+ * SHA: Add a runtime sanity check that sha commands output something
+ that appears to be a real sha.
-- Joey Hess <joeyh@debian.org> Thu, 02 May 2013 20:39:19 -0400