diff --git a/CHANGELOG.md b/CHANGELOG.md --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -1,5 +1,39 @@ # Changelog +## 0.2.0.0 -- 2026-09-08 + +Corrects four FFI signatures that did not match the s2n-tls C API. These were +found by auditing all 245 wrapped functions against the s2n-tls 1.6.4 header. +`cbits/s2n_wrapper.c` does not include `s2n.h`, so none of them were caught at +compile time. + +### Breaking changes + +* `s2n_client_hello_has_extension` and `s2n_cert_get_x509_extension_value` take + `Ptr CBool` for their `bool *` out-parameters, previously `Ptr CInt`. s2n + writes a single byte, so callers that allocated a `CInt` read three bytes of + uninitialized memory and could see a nonzero result for an absent extension. + Callers must switch to `alloca @CBool`. +* `S2nCertTiebreakCallback` is now + `Ptr S2nCertChainAndKey -> Ptr S2nCertChainAndKey -> Ptr Word8 -> Word32 -> IO (Ptr S2nCertChainAndKey)`. + The previous type took the certificate name by value instead of by pointer, + took the name length by pointer instead of by value, and returned `CInt` + where s2n expects a certificate chain pointer. Installing a tiebreak callback + built against the old type would have crashed. +* `S2nMemMallocCallback` takes `Ptr Word32` for its `allocated` out-parameter, + previously `Word32`. A custom allocator had no way to report its allocation + size back to s2n. + +### Fixed + +* Missing optional symbols are recorded in `missingSymbols` again. `dlsym` + throws an `IOError` for an absent symbol rather than returning `nullFunPtr`, + which made the null checks in the loader dead code -- a missing optional + symbol escaped `withS2nTlsFfi` as an opaque `user error` and `missingSymbols` + could never report anything but `[]`. +* A missing error-reporting symbol now raises the typed `RequiredSymbolNotFound` + instead of an untyped `IOError`. + ## 0.1.0.0 -- 2026-04-28 * Initial release diff --git a/cbits/s2n_wrapper.c b/cbits/s2n_wrapper.c --- a/cbits/s2n_wrapper.c +++ b/cbits/s2n_wrapper.c @@ -1393,8 +1393,8 @@ } int s2n_wrap_client_hello_has_extension( - int (*fn)(void *, uint16_t, int *), - void *client_hello, uint16_t extension_iana, int *exists, + int (*fn)(void *, uint16_t, bool *), + void *client_hello, uint16_t extension_iana, bool *exists, const S2nErrorFuncs *err_funcs, S2nErrorInfo *err_out) { int result = fn(client_hello, extension_iana, exists); @@ -2394,8 +2394,8 @@ } int s2n_wrap_cert_get_x509_extension_value( - int (*fn)(void *, const uint8_t *, uint8_t *, uint32_t *, int *), - void *cert, const uint8_t *oid, uint8_t *value, uint32_t *length, int *critical, + int (*fn)(void *, const uint8_t *, uint8_t *, uint32_t *, bool *), + void *cert, const uint8_t *oid, uint8_t *value, uint32_t *length, bool *critical, const S2nErrorFuncs *err_funcs, S2nErrorInfo *err_out) { int result = fn(cert, oid, value, length, critical); diff --git a/cbits/s2n_wrapper.h b/cbits/s2n_wrapper.h --- a/cbits/s2n_wrapper.h +++ b/cbits/s2n_wrapper.h @@ -602,8 +602,8 @@ const S2nErrorFuncs *err_funcs, S2nErrorInfo *err_out); int s2n_wrap_client_hello_has_extension( - int (*fn)(void *, uint16_t, int *), - void *client_hello, uint16_t extension_iana, int *exists, + int (*fn)(void *, uint16_t, bool *), + void *client_hello, uint16_t extension_iana, bool *exists, const S2nErrorFuncs *err_funcs, S2nErrorInfo *err_out); int s2n_wrap_client_hello_get_session_id_length( @@ -985,8 +985,8 @@ const S2nErrorFuncs *err_funcs, S2nErrorInfo *err_out); int s2n_wrap_cert_get_x509_extension_value( - int (*fn)(void *, const uint8_t *, uint8_t *, uint32_t *, int *), - void *cert, const uint8_t *oid, uint8_t *value, uint32_t *length, int *critical, + int (*fn)(void *, const uint8_t *, uint8_t *, uint32_t *, bool *), + void *cert, const uint8_t *oid, uint8_t *value, uint32_t *length, bool *critical, const S2nErrorFuncs *err_funcs, S2nErrorInfo *err_out); int s2n_wrap_cert_get_utf8_string_from_extension_data_length( diff --git a/s2n-tls-ffi.cabal b/s2n-tls-ffi.cabal --- a/s2n-tls-ffi.cabal +++ b/s2n-tls-ffi.cabal @@ -1,6 +1,6 @@ cabal-version: 3.0 name: s2n-tls-ffi -version: 0.1.0.0 +version: 0.2.0.0 synopsis: Low-level FFI bindings to the s2n-tls library description: Low-level FFI bindings to the s2n-tls library. @@ -12,7 +12,7 @@ copyright: 2026 Daniel Goertzen category: Cryptography, FFI, Network build-type: Simple -tested-with: GHC == 9.8.2 +tested-with: GHC == 9.12.2 extra-doc-files: CHANGELOG.md README.md @@ -27,7 +27,7 @@ source-repository this type: git location: https://github.com/goertzenator/s2n-tls-ffi.git - tag: v0.1.0.0 + tag: v0.2.0.0 library exposed-modules: diff --git a/src/S2nTls/Ffi.hs b/src/S2nTls/Ffi.hs --- a/src/S2nTls/Ffi.hs +++ b/src/S2nTls/Ffi.hs @@ -112,7 +112,7 @@ S2nErrorFuncs (..), ) where -import Control.Exception (Exception, bracket, throwIO) +import Control.Exception (Exception, IOException, bracket, catch, throwIO) import Control.Monad (when) import Data.IORef (modifyIORef', newIORef, readIORef) import Data.Word (Word16, Word32, Word64, Word8) @@ -235,13 +235,33 @@ openLib :: FilePath -> IO DL openLib path = dlopen path [RTLD_LAZY, RTLD_LOCAL] --- | Load the error functions (required for meaningful error reporting) +{- | Look up a symbol, yielding 'nullFunPtr' when it is absent. + +'dlsym' signals a missing symbol by throwing an untyped 'IOError' rather than +returning 'nullFunPtr', so every caller that wants to tolerate a missing symbol +has to recover it explicitly. +-} +dlsymMaybe :: DL -> String -> IO (FunPtr a) +dlsymMaybe dl name = dlsym dl name `catch` \(_ :: IOException) -> pure nullFunPtr + +{- | Load the error functions (required for meaningful error reporting). + +Every wrapper calls through these unconditionally -- 's2n_send' and 's2n_recv' +do so even on the success path -- so a null here would be an immediate segfault +inside C. Fail at load time with a typed 'RequiredSymbolNotFound' instead. +-} loadErrorFuncs :: DL -> IO S2nErrorFuncs -loadErrorFuncs dl = do - el <- dlsym dl "s2n_errno_location" - sd <- dlsym dl "s2n_strerror_debug" - et <- dlsym dl "s2n_error_get_type" - pure $ S2nErrorFuncs el sd et +loadErrorFuncs dl = + S2nErrorFuncs + <$> loadRequired "s2n_errno_location" + <*> loadRequired "s2n_strerror_debug" + <*> loadRequired "s2n_error_get_type" + where + loadRequired :: String -> IO (FunPtr a) + loadRequired name = do + ptr <- dlsymMaybe dl name + when (ptr == nullFunPtr) $ throwIO (RequiredSymbolNotFound name) + pure ptr -- | Create a closure that throws MissingSymbol throwMissing :: String -> IO a @@ -262,7 +282,7 @@ -- Helper to load a symbol with forgiving behavior load :: String -> MethodRequirement -> IO (FunPtr a) load name req = do - ptr <- dlsym dl name + ptr <- dlsymMaybe dl name when (ptr == nullFunPtr) $ do modifyIORef' missingRef (name :) if ptr == nullFunPtr && req == Mandatory @@ -784,7 +804,7 @@ foreign import ccall safe "s2n_wrap_client_hello_get_extensions" c_wrap_client_hello_get_extensions :: FunPtr () -> Ptr S2nClientHello -> Ptr Word8 -> Word32 -> Ptr S2nErrorFuncs -> Ptr S2nError -> IO CSsize foreign import ccall safe "s2n_wrap_client_hello_get_extension_length" c_wrap_client_hello_get_extension_length :: FunPtr () -> Ptr S2nClientHello -> S2nTlsExtensionType -> Ptr S2nErrorFuncs -> Ptr S2nError -> IO CSsize foreign import ccall safe "s2n_wrap_client_hello_get_extension_by_id" c_wrap_client_hello_get_extension_by_id :: FunPtr () -> Ptr S2nClientHello -> S2nTlsExtensionType -> Ptr Word8 -> Word32 -> Ptr S2nErrorFuncs -> Ptr S2nError -> IO CSsize -foreign import ccall safe "s2n_wrap_client_hello_has_extension" c_wrap_client_hello_has_extension :: FunPtr () -> Ptr S2nClientHello -> Word16 -> Ptr CInt -> Ptr S2nErrorFuncs -> Ptr S2nError -> IO CInt +foreign import ccall safe "s2n_wrap_client_hello_has_extension" c_wrap_client_hello_has_extension :: FunPtr () -> Ptr S2nClientHello -> Word16 -> Ptr CBool -> Ptr S2nErrorFuncs -> Ptr S2nError -> IO CInt foreign import ccall safe "s2n_wrap_client_hello_get_session_id_length" c_wrap_client_hello_get_session_id_length :: FunPtr () -> Ptr S2nClientHello -> Ptr Word32 -> Ptr S2nErrorFuncs -> Ptr S2nError -> IO CInt foreign import ccall safe "s2n_wrap_client_hello_get_session_id" c_wrap_client_hello_get_session_id :: FunPtr () -> Ptr S2nClientHello -> Ptr Word8 -> Ptr Word32 -> Word32 -> Ptr S2nErrorFuncs -> Ptr S2nError -> IO CInt foreign import ccall safe "s2n_wrap_client_hello_get_compression_methods_length" c_wrap_client_hello_get_compression_methods_length :: FunPtr () -> Ptr S2nClientHello -> Ptr Word32 -> Ptr S2nErrorFuncs -> Ptr S2nError -> IO CInt @@ -857,7 +877,7 @@ foreign import ccall safe "s2n_wrap_cert_get_der" c_wrap_cert_get_der :: FunPtr () -> Ptr S2nCert -> Ptr (Ptr Word8) -> Ptr Word32 -> Ptr S2nErrorFuncs -> Ptr S2nError -> IO CInt foreign import ccall safe "s2n_wrap_connection_get_peer_cert_chain" c_wrap_connection_get_peer_cert_chain :: FunPtr () -> Ptr S2nConnection -> Ptr S2nCertChainAndKey -> Ptr S2nErrorFuncs -> Ptr S2nError -> IO CInt foreign import ccall safe "s2n_wrap_cert_get_x509_extension_value_length" c_wrap_cert_get_x509_extension_value_length :: FunPtr () -> Ptr S2nCert -> Ptr Word8 -> Ptr Word32 -> Ptr S2nErrorFuncs -> Ptr S2nError -> IO CInt -foreign import ccall safe "s2n_wrap_cert_get_x509_extension_value" c_wrap_cert_get_x509_extension_value :: FunPtr () -> Ptr S2nCert -> Ptr Word8 -> Ptr Word8 -> Ptr Word32 -> Ptr CInt -> Ptr S2nErrorFuncs -> Ptr S2nError -> IO CInt +foreign import ccall safe "s2n_wrap_cert_get_x509_extension_value" c_wrap_cert_get_x509_extension_value :: FunPtr () -> Ptr S2nCert -> Ptr Word8 -> Ptr Word8 -> Ptr Word32 -> Ptr CBool -> Ptr S2nErrorFuncs -> Ptr S2nError -> IO CInt foreign import ccall safe "s2n_wrap_cert_get_utf8_string_from_extension_data_length" c_wrap_cert_get_utf8_string_from_extension_data_length :: FunPtr () -> Ptr Word8 -> Word32 -> Ptr Word32 -> Ptr S2nErrorFuncs -> Ptr S2nError -> IO CInt foreign import ccall safe "s2n_wrap_cert_get_utf8_string_from_extension_data" c_wrap_cert_get_utf8_string_from_extension_data :: FunPtr () -> Ptr Word8 -> Word32 -> Ptr Word8 -> Ptr Word32 -> Ptr S2nErrorFuncs -> Ptr S2nError -> IO CInt foreign import ccall safe "s2n_wrap_external_psk_new" c_wrap_external_psk_new :: FunPtr () -> Ptr S2nErrorFuncs -> Ptr S2nError -> IO (Ptr S2nPsk) diff --git a/src/S2nTls/Ffi/Types.hs b/src/S2nTls/Ffi/Types.hs --- a/src/S2nTls/Ffi/Types.hs +++ b/src/S2nTls/Ffi/Types.hs @@ -790,7 +790,7 @@ type S2nMemCleanupCallback = FunPtr (IO CInt) -- | Memory allocation callback. -type S2nMemMallocCallback = FunPtr (Ptr (Ptr ()) -> Word32 -> Word32 -> IO CInt) +type S2nMemMallocCallback = FunPtr (Ptr (Ptr ()) -> Word32 -> Ptr Word32 -> IO CInt) -- | Memory free callback. type S2nMemFreeCallback = FunPtr (Ptr () -> Word32 -> IO CInt) @@ -811,7 +811,7 @@ type S2nClientHelloFn = FunPtr (Ptr S2nConnection -> Ptr () -> IO CInt) -- | Certificate tiebreak callback. -type S2nCertTiebreakCallback = FunPtr (Ptr S2nCertChainAndKey -> Ptr S2nCertChainAndKey -> Word8 -> Ptr (Ptr S2nCertChainAndKey) -> IO CInt) +type S2nCertTiebreakCallback = FunPtr (Ptr S2nCertChainAndKey -> Ptr S2nCertChainAndKey -> Ptr Word8 -> Word32 -> IO (Ptr S2nCertChainAndKey)) -- | Verify host callback. type S2nVerifyHostFn = FunPtr (CString -> CSize -> Ptr () -> IO Word8) @@ -972,7 +972,7 @@ , s2n_client_hello_get_extensions :: Ptr S2nClientHello -> Ptr Word8 -> Word32 -> IO (Either S2nError CSsize) , s2n_client_hello_get_extension_length :: Ptr S2nClientHello -> S2nTlsExtensionType -> IO (Either S2nError CSsize) , s2n_client_hello_get_extension_by_id :: Ptr S2nClientHello -> S2nTlsExtensionType -> Ptr Word8 -> Word32 -> IO (Either S2nError CSsize) - , s2n_client_hello_has_extension :: Ptr S2nClientHello -> Word16 -> Ptr CInt -> IO (Either S2nError CInt) + , s2n_client_hello_has_extension :: Ptr S2nClientHello -> Word16 -> Ptr CBool -> IO (Either S2nError CInt) , s2n_client_hello_get_session_id_length :: Ptr S2nClientHello -> Ptr Word32 -> IO (Either S2nError CInt) , s2n_client_hello_get_session_id :: Ptr S2nClientHello -> Ptr Word8 -> Ptr Word32 -> Word32 -> IO (Either S2nError CInt) , s2n_client_hello_get_compression_methods_length :: Ptr S2nClientHello -> Ptr Word32 -> IO (Either S2nError CInt) @@ -1062,7 +1062,7 @@ , s2n_cert_get_der :: Ptr S2nCert -> Ptr (Ptr Word8) -> Ptr Word32 -> IO (Either S2nError CInt) , s2n_connection_get_peer_cert_chain :: Ptr S2nConnection -> Ptr S2nCertChainAndKey -> IO (Either S2nError CInt) , s2n_cert_get_x509_extension_value_length :: Ptr S2nCert -> Ptr Word8 -> Ptr Word32 -> IO (Either S2nError CInt) - , s2n_cert_get_x509_extension_value :: Ptr S2nCert -> Ptr Word8 -> Ptr Word8 -> Ptr Word32 -> Ptr CInt -> IO (Either S2nError CInt) + , s2n_cert_get_x509_extension_value :: Ptr S2nCert -> Ptr Word8 -> Ptr Word8 -> Ptr Word32 -> Ptr CBool -> IO (Either S2nError CInt) , s2n_cert_get_utf8_string_from_extension_data_length :: Ptr Word8 -> Word32 -> Ptr Word32 -> IO (Either S2nError CInt) , s2n_cert_get_utf8_string_from_extension_data :: Ptr Word8 -> Word32 -> Ptr Word8 -> Ptr Word32 -> IO (Either S2nError CInt) , s2n_external_psk_new :: IO (Either S2nError (Ptr S2nPsk))