diff options
author | Joey Hess <joeyh@joeyh.name> | 2017-02-24 15:16:56 -0400 |
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committer | Joey Hess <joeyh@joeyh.name> | 2017-02-24 15:16:56 -0400 |
commit | 2f868db90c7ba16eee901b9b1472b1e1a889dd93 (patch) | |
tree | 8a366a36cc50cf1c3899aeaddf10e02d9cffc847 /Key.hs | |
parent | 13fb898fb2379a9ed9b7df2b645453059d296488 (diff) |
add KeyVariety type
Where before the "name" of a key and a backend was a string, this makes
it a concrete data type.
This is groundwork for allowing some varieties of keys to be disabled
in file2key, so git-annex won't use them at all.
Benchmarks ran in my big repo:
old git-annex info:
real 0m3.338s
user 0m3.124s
sys 0m0.244s
new git-annex info:
real 0m3.216s
user 0m3.024s
sys 0m0.220s
new git-annex find:
real 0m7.138s
user 0m6.924s
sys 0m0.252s
old git-annex find:
real 0m7.433s
user 0m7.240s
sys 0m0.232s
Surprising result; I'd have expected it to be slower since it now parses
all the key varieties. But, the parser is very simple and perhaps
sharing KeyVarieties uses less memory or something like that.
This commit was supported by the NSF-funded DataLad project.
Diffstat (limited to 'Key.hs')
-rw-r--r-- | Key.hs | 30 |
1 files changed, 13 insertions, 17 deletions
@@ -35,7 +35,7 @@ import qualified Utility.SimpleProtocol as Proto stubKey :: Key stubKey = Key { keyName = "" - , keyBackendName = "" + , keyVariety = OtherKey "" , keySize = Nothing , keyMtime = Nothing , keyChunkSize = Nothing @@ -69,8 +69,8 @@ fieldSep = '-' - The name field is always shown last, separated by doubled fieldSeps, - and is the only field allowed to contain the fieldSep. -} key2file :: Key -> FilePath -key2file Key { keyBackendName = b, keySize = s, keyMtime = m, keyChunkSize = cs, keyChunkNum = cn, keyName = n } = - b +++ ('s' ?: s) +++ ('m' ?: m) +++ ('S' ?: cs) +++ ('C' ?: cn) +++ (fieldSep : n) +key2file Key { keyVariety = kv, keySize = s, keyMtime = m, keyChunkSize = cs, keyChunkNum = cn, keyName = n } = + formatKeyVariety kv +++ ('s' ?: s) +++ ('m' ?: m) +++ ('S' ?: cs) +++ ('C' ?: cn) +++ (fieldSep : n) where "" +++ y = y x +++ "" = x @@ -80,12 +80,12 @@ key2file Key { keyBackendName = b, keySize = s, keyMtime = m, keyChunkSize = cs, file2key :: FilePath -> Maybe Key file2key s - | key == Just stubKey || (keyName <$> key) == Just "" || (keyBackendName <$> key) == Just "" = Nothing + | key == Just stubKey || (keyName <$> key) == Just "" || (keyVariety <$> key) == Just (OtherKey "") = Nothing | otherwise = key where key = startbackend stubKey s - startbackend k v = sepfield k v addbackend + startbackend k v = sepfield k v addvariety sepfield k v a = case span (/= fieldSep) v of (v', _:r) -> findfields r $ a k v' @@ -96,7 +96,7 @@ file2key s | otherwise = sepfield k v $ addfield c findfields _ v = v - addbackend k v = Just k { keyBackendName = v } + addvariety k v = Just k { keyVariety = parseKeyVariety v } -- This is a strict parser for security reasons; a key -- can contain only 4 fields, which all consist only of numbers. @@ -126,31 +126,27 @@ file2key s | validKeyName k v = Just $ k { keyName = v } | otherwise = Nothing -{- A key with a backend ending in "E" is an extension preserving key, - - using some hash. +{- When a key HasExt, the length of the extension is limited in order to + - mitigate against SHA1 collision attacks (specifically, chosen-prefix + - attacks). - - - The length of the extension is limited in order to mitigate against - - SHA1 collision attacks (specifically, chosen-prefix attacks). - In such an attack, the extension of the key could be made to contain - the collision generation data, with the result that a signed git commit - including such keys would not be secure. - - The maximum extension length ever generated for such a key was 8 - characters; 20 is used here to give a little future wiggle-room. - - The SHA1 common-prefix attack used 128 bytes of data. - - - - This code is here, and not in Backend.Hash (where it really belongs) - - so that file2key can check it whenever a Key is constructed. + - The SHA1 common-prefix attack needs 128 bytes of data. -} validKeyName :: Key -> String -> Bool -validKeyName k v - | end (keyBackendName k) == "E" = length (takeExtensions v) <= 20 +validKeyName k name + | hasExt (keyVariety k) = length (takeExtensions name) <= 20 | otherwise = True instance Arbitrary Key where arbitrary = Key <$> (listOf1 $ elements $ ['A'..'Z'] ++ ['a'..'z'] ++ ['0'..'9'] ++ "-_\r\n \t") - <*> (listOf1 $ elements ['A'..'Z']) -- BACKEND + <*> (parseKeyVariety <$> (listOf1 $ elements ['A'..'Z'])) -- BACKEND <*> ((abs <$>) <$> arbitrary) -- size cannot be negative <*> arbitrary <*> ((abs <$>) <$> arbitrary) -- chunksize cannot be negative |