commit 41855291dc1943189ade89d7d519c002f32cd721
parent 56d27f6673b4a125218f55ff1ee0d2d74889183b
Author: Jared Tobin <jared@jtobin.io>
Date: Sun, 25 Jan 2026 10:29:31 +0400
fix: reject unknown even TLV types in extensions
Per BOLT #1, unknown even TLV types must cause failure. The previous
implementation used decodeTlvStreamRaw for extensions, which accepts
all types without enforcing the even/odd rule.
Now decodeEnvelope uses decodeTlvStreamWith (const False), which:
- Rejects unknown even types (fails per spec)
- Skips unknown odd types (ignores per spec)
Also updates decodeTlvStreamRaw docstring to clarify it does NOT
enforce the BOLT #1 unknown-even-type rule.
Tests updated to verify:
- Unknown even types in extensions cause DecodeInvalidExtension error
- Unknown odd types in extensions are skipped (not returned)
- Mixed even/odd extensions fail on the even type
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Diffstat:
2 files changed, 35 insertions(+), 23 deletions(-)
diff --git a/lib/Lightning/Protocol/BOLT1.hs b/lib/Lightning/Protocol/BOLT1.hs
@@ -250,8 +250,9 @@ instance NFData TlvError
-- - Types must be strictly increasing
-- - Lengths must not exceed bounds
--
--- All records are returned regardless of type. Use this for parsing
--- extension TLVs or when you want to handle type validation separately.
+-- All records are returned regardless of type. Note: this does NOT
+-- enforce the BOLT #1 unknown-even-type rule. Use 'decodeTlvStreamWith'
+-- with an appropriate predicate for spec-compliant parsing.
decodeTlvStreamRaw :: BS.ByteString -> Either TlvError TlvStream
decodeTlvStreamRaw = go Nothing []
where
@@ -748,9 +749,10 @@ decodeEnvelope !bs = do
_ -> do
(msg, rest2) <- decodeMessage msgType rest1
-- Parse any remaining bytes as extension TLV
+ -- Per BOLT #1: unknown even types must fail, unknown odd are ignored
ext <- if BS.null rest2
then Right Nothing
- else case decodeTlvStreamRaw rest2 of
+ else case decodeTlvStreamWith (const False) rest2 of
Left e -> Left (DecodeInvalidExtension e)
Right s -> Right (Just s)
Right (Just msg, ext)
diff --git a/test/Main.hs b/test/Main.hs
@@ -326,46 +326,55 @@ envelope_tests = testGroup "Envelope" [
extension_tests :: TestTree
extension_tests = testGroup "Extension TLV" [
- testCase "encode envelope with extension" $ do
+ testCase "encode envelope with extension (odd type)" $ do
let msg = MsgPingVal (Ping 10 "")
- ext = TlvStream [TlvRecord 100 "extension data"]
+ ext = TlvStream [TlvRecord 101 "extension data"] -- odd type
case encodeEnvelope msg (Just ext) of
Left e -> assertFailure $ "encode failed: " ++ show e
Right encoded -> do
-- Should contain message + extension
assertBool "encoded should be longer" (BS.length encoded > 6)
- , testCase "decode envelope with extension roundtrip" $ do
+ , testCase "decode envelope with odd extension - skipped per BOLT#1" $ do
+ -- Per BOLT #1: unknown odd types are ignored (skipped)
let msg = MsgPingVal (Ping 10 "")
- ext = TlvStream [TlvRecord 101 "ext"]
+ ext = TlvStream [TlvRecord 101 "ext"] -- odd type
case encodeEnvelope msg (Just ext) of
Left e -> assertFailure $ "encode failed: " ++ show e
Right encoded -> case decodeEnvelope encoded of
- Right (Just decoded, Just decodedExt) -> do
+ Right (Just decoded, Just (TlvStream [])) -> do
+ -- Extension is empty because unknown odd types are skipped
decoded @?= msg
- length (unTlvStream decodedExt) @?= 1
other -> assertFailure $ "unexpected: " ++ show other
- , testCase "decode envelope extension is parsed" $ do
- -- Manually construct ping + extension TLV
+ , testCase "decode envelope with unknown even extension fails" $ do
+ -- Per BOLT #1: unknown even types must cause failure
let pingPayload = mconcat [encodeU16 10, encodeU16 0] -- numPong=10, len=0
- extTlv = mconcat [encodeBigSize 200, encodeBigSize 3, "abc"]
+ extTlv = mconcat [encodeBigSize 100, encodeBigSize 3, "abc"] -- even!
envelope = encodeU16 18 <> pingPayload <> extTlv -- type 18 = ping
case decodeEnvelope envelope of
- Right (Just (MsgPingVal ping), Just (TlvStream [r])) -> do
- pingNumPongBytes ping @?= 10
- tlvType r @?= 200
- tlvValue r @?= "abc"
- other -> assertFailure $ "unexpected: " ++ show other
+ Left (DecodeInvalidExtension (TlvUnknownEvenType 100)) -> pure ()
+ other -> assertFailure $ "expected unknown even error: " ++ show other
, testCase "decode envelope with invalid extension fails" $ do
-- Ping + invalid TLV (non-strictly-increasing)
let pingPayload = mconcat [encodeU16 10, encodeU16 0]
badTlv = mconcat [
- encodeBigSize 100, encodeBigSize 1, "a"
- , encodeBigSize 50, encodeBigSize 1, "b" -- 50 < 100, invalid
+ encodeBigSize 101, encodeBigSize 1, "a" -- odd types for this test
+ , encodeBigSize 51, encodeBigSize 1, "b" -- 51 < 101, invalid
]
envelope = encodeU16 18 <> pingPayload <> badTlv
case decodeEnvelope envelope of
Left (DecodeInvalidExtension TlvNotStrictlyIncreasing) -> pure ()
other -> assertFailure $ "expected invalid extension: " ++ show other
+ , testCase "unknown even in extension fails even with odd types present" $ do
+ -- Mixed odd and even - should fail on the even type
+ let pingPayload = mconcat [encodeU16 10, encodeU16 0]
+ extTlv = mconcat [
+ encodeBigSize 101, encodeBigSize 1, "a" -- odd, would be skipped
+ , encodeBigSize 200, encodeBigSize 1, "b" -- even, must fail
+ ]
+ envelope = encodeU16 18 <> pingPayload <> extTlv
+ case decodeEnvelope envelope of
+ Left (DecodeInvalidExtension (TlvUnknownEvenType 200)) -> pure ()
+ other -> assertFailure $ "expected unknown even error: " ++ show other
]
-- Bounds checking tests -------------------------------------------------------
@@ -450,15 +459,16 @@ property_tests = testGroup "Properties" [
Right (MsgErrorVal decoded, rest) ->
decoded == msg && BS.null rest
_ -> False
- , testProperty "Envelope with extension roundtrip" $ \bs ->
+ , testProperty "Envelope with odd extension (skipped per BOLT#1)" $ \bs ->
+ -- Unknown odd types in extensions are skipped per BOLT #1
let msg = MsgPingVal (Ping 42 "")
extData = BS.pack (take 100 bs)
- ext = TlvStream [TlvRecord 101 extData]
+ ext = TlvStream [TlvRecord 101 extData] -- odd type, will be skipped
in case encodeEnvelope msg (Just ext) of
Left _ -> False
Right encoded -> case decodeEnvelope encoded of
- Right (Just decoded, Just (TlvStream [r])) ->
- decoded == msg && tlvType r == 101 && tlvValue r == extData
+ -- Extension should be empty (odd types skipped)
+ Right (Just decoded, Just (TlvStream [])) -> decoded == msg
_ -> False
]
