tls-1.5.1: Network/TLS/Handshake/Server.hs
{-# LANGUAGE OverloadedStrings #-}
-- |
-- Module : Network.TLS.Handshake.Server
-- License : BSD-style
-- Maintainer : Vincent Hanquez <vincent@snarc.org>
-- Stability : experimental
-- Portability : unknown
--
module Network.TLS.Handshake.Server
( handshakeServer
, handshakeServerWith
, requestCertificateServer
, postHandshakeAuthServerWith
) where
import Network.TLS.Parameters
import Network.TLS.Imports
import Network.TLS.Context.Internal
import Network.TLS.Session
import Network.TLS.Struct
import Network.TLS.Struct13
import Network.TLS.Cipher
import Network.TLS.Compression
import Network.TLS.Credentials
import Network.TLS.Crypto
import Network.TLS.Extension
import Network.TLS.Util (bytesEq, catchException, fromJust)
import Network.TLS.IO
import Network.TLS.Types
import Network.TLS.State
import Network.TLS.Handshake.State
import Network.TLS.Handshake.Process
import Network.TLS.Handshake.Key
import Network.TLS.Handshake.Random
import Network.TLS.Measurement
import qualified Data.ByteString as B
import Data.X509 (ExtKeyUsageFlag(..))
import Control.Monad.State.Strict
import Control.Exception (bracket)
import Network.TLS.Handshake.Signature
import Network.TLS.Handshake.Common
import Network.TLS.Handshake.Certificate
import Network.TLS.X509
import Network.TLS.Handshake.State13
import Network.TLS.KeySchedule
import Network.TLS.Handshake.Common13
-- Put the server context in handshake mode.
--
-- Expect to receive as first packet a client hello handshake message
--
-- This is just a helper to pop the next message from the recv layer,
-- and call handshakeServerWith.
handshakeServer :: ServerParams -> Context -> IO ()
handshakeServer sparams ctx = liftIO $ do
hss <- recvPacketHandshake ctx
case hss of
[ch] -> handshakeServerWith sparams ctx ch
_ -> unexpected (show hss) (Just "client hello")
-- | Put the server context in handshake mode.
--
-- Expect a client hello message as parameter.
-- This is useful when the client hello has been already poped from the recv layer to inspect the packet.
--
-- When the function returns, a new handshake has been succesfully negociated.
-- On any error, a HandshakeFailed exception is raised.
--
-- handshake protocol (<- receiving, -> sending, [] optional):
-- (no session) (session resumption)
-- <- client hello <- client hello
-- -> server hello -> server hello
-- -> [certificate]
-- -> [server key xchg]
-- -> [cert request]
-- -> hello done
-- <- [certificate]
-- <- client key xchg
-- <- [cert verify]
-- <- change cipher -> change cipher
-- <- finish -> finish
-- -> change cipher <- change cipher
-- -> finish <- finish
--
handshakeServerWith :: ServerParams -> Context -> Handshake -> IO ()
handshakeServerWith sparams ctx clientHello@(ClientHello legacyVersion _ clientSession ciphers compressions exts _) = do
established <- ctxEstablished ctx
-- renego is not allowed in TLS 1.3
when (established /= NotEstablished) $ do
ver <- usingState_ ctx (getVersionWithDefault TLS10)
when (ver == TLS13) $ throwCore $ Error_Protocol ("renegotiation is not allowed in TLS 1.3", True, UnexpectedMessage)
-- rejecting client initiated renegotiation to prevent DOS.
eof <- ctxEOF ctx
let renegotiation = established == Established && not eof
when (renegotiation && not (supportedClientInitiatedRenegotiation $ ctxSupported ctx)) $
throwCore $ Error_Protocol ("renegotiation is not allowed", False, NoRenegotiation)
-- check if policy allow this new handshake to happens
handshakeAuthorized <- withMeasure ctx (onNewHandshake $ serverHooks sparams)
unless handshakeAuthorized (throwCore $ Error_HandshakePolicy "server: handshake denied")
updateMeasure ctx incrementNbHandshakes
-- Handle Client hello
processHandshake ctx clientHello
-- rejecting SSL2. RFC 6176
when (legacyVersion == SSL2) $ throwCore $ Error_Protocol ("SSL 2.0 is not supported", True, ProtocolVersion)
-- rejecting SSL3. RFC 7568
-- when (legacyVersion == SSL3) $ throwCore $ Error_Protocol ("SSL 3.0 is not supported", True, ProtocolVersion)
-- Fallback SCSV: RFC7507
-- TLS_FALLBACK_SCSV: {0x56, 0x00}
when (supportedFallbackScsv (ctxSupported ctx) &&
(0x5600 `elem` ciphers) &&
legacyVersion < TLS12) $
throwCore $ Error_Protocol ("fallback is not allowed", True, InappropriateFallback)
-- choosing TLS version
let clientVersions = case extensionLookup extensionID_SupportedVersions exts >>= extensionDecode MsgTClientHello of
Just (SupportedVersionsClientHello vers) -> vers
_ -> []
clientVersion = min TLS12 legacyVersion
serverVersions
| renegotiation = filter (< TLS13) (supportedVersions $ ctxSupported ctx)
| otherwise = supportedVersions $ ctxSupported ctx
mVersion = debugVersionForced $ serverDebug sparams
chosenVersion <- case mVersion of
Just cver -> return cver
Nothing ->
if (TLS13 `elem` serverVersions) && clientVersions /= [] then case findHighestVersionFrom13 clientVersions serverVersions of
Nothing -> throwCore $ Error_Protocol ("client versions " ++ show clientVersions ++ " is not supported", True, ProtocolVersion)
Just v -> return v
else case findHighestVersionFrom clientVersion serverVersions of
Nothing -> throwCore $ Error_Protocol ("client version " ++ show clientVersion ++ " is not supported", True, ProtocolVersion)
Just v -> return v
-- SNI (Server Name Indication)
let serverName = case extensionLookup extensionID_ServerName exts >>= extensionDecode MsgTClientHello of
Just (ServerName ns) -> listToMaybe (mapMaybe toHostName ns)
where toHostName (ServerNameHostName hostName) = Just hostName
toHostName (ServerNameOther _) = Nothing
_ -> Nothing
maybe (return ()) (usingState_ ctx . setClientSNI) serverName
-- ALPN (Application Layer Protocol Negotiation)
case extensionLookup extensionID_ApplicationLayerProtocolNegotiation exts >>= extensionDecode MsgTClientHello of
Just (ApplicationLayerProtocolNegotiation protos) -> usingState_ ctx $ setClientALPNSuggest protos
_ -> return ()
extraCreds <- onServerNameIndication (serverHooks sparams) serverName
let allCreds = extraCreds `mappend` sharedCredentials (ctxShared ctx)
-- TLS version dependent
if chosenVersion <= TLS12 then
handshakeServerWithTLS12 sparams ctx chosenVersion allCreds exts ciphers serverName clientVersion compressions clientSession
else do
mapM_ ensureNullCompression compressions
-- fixme: we should check if the client random is the same as
-- that in the first client hello in the case of hello retry.
handshakeServerWithTLS13 sparams ctx chosenVersion allCreds exts ciphers serverName clientSession
handshakeServerWith _ _ _ = throwCore $ Error_Protocol ("unexpected handshake message received in handshakeServerWith", True, HandshakeFailure)
-- TLS 1.2 or earlier
handshakeServerWithTLS12 :: ServerParams
-> Context
-> Version
-> Credentials
-> [ExtensionRaw]
-> [CipherID]
-> Maybe String
-> Version
-> [CompressionID]
-> Session
-> IO ()
handshakeServerWithTLS12 sparams ctx chosenVersion allCreds exts ciphers serverName clientVersion compressions clientSession = do
-- If compression is null, commonCompressions should be [0].
when (null commonCompressions) $ throwCore $
Error_Protocol ("no compression in common with the client", True, HandshakeFailure)
-- When selecting a cipher we must ensure that it is allowed for the
-- TLS version but also that all its key-exchange requirements
-- will be met.
-- Some ciphers require a signature and a hash. With TLS 1.2 the hash
-- algorithm is selected from a combination of server configuration and
-- the client "supported_signatures" extension. So we cannot pick
-- such a cipher if no hash is available for it. It's best to skip this
-- cipher and pick another one (with another key exchange).
-- Cipher selection is performed in two steps: first server credentials
-- are flagged as not suitable for signature if not compatible with
-- negotiated signature parameters. Then ciphers are evalutated from
-- the resulting credentials.
let possibleGroups = negotiatedGroupsInCommon ctx exts
possibleECGroups = possibleGroups `intersect` availableECGroups
possibleFFGroups = possibleGroups `intersect` availableFFGroups
hasCommonGroupForECDHE = not (null possibleECGroups)
hasCommonGroupForFFDHE = not (null possibleFFGroups)
hasCustomGroupForFFDHE = isJust (serverDHEParams sparams)
canFFDHE = hasCustomGroupForFFDHE || hasCommonGroupForFFDHE
hasCommonGroup cipher =
case cipherKeyExchange cipher of
CipherKeyExchange_DH_Anon -> canFFDHE
CipherKeyExchange_DHE_RSA -> canFFDHE
CipherKeyExchange_DHE_DSS -> canFFDHE
CipherKeyExchange_ECDHE_RSA -> hasCommonGroupForECDHE
CipherKeyExchange_ECDHE_ECDSA -> hasCommonGroupForECDHE
_ -> True -- group not used
-- Ciphers are selected according to TLS version, availability of
-- (EC)DHE group and credential depending on key exchange.
cipherAllowed cipher = cipherAllowedForVersion chosenVersion cipher && hasCommonGroup cipher
selectCipher credentials signatureCredentials = filter cipherAllowed (commonCiphers credentials signatureCredentials)
(creds, signatureCreds, ciphersFilteredVersion)
= case chosenVersion of
TLS12 -> let -- Build a list of all hash/signature algorithms in common between
-- client and server.
possibleHashSigAlgs = hashAndSignaturesInCommon ctx exts
-- Check that a candidate signature credential will be compatible with
-- client & server hash/signature algorithms. This returns Just Int
-- in order to sort credentials according to server hash/signature
-- preference. When the certificate has no matching hash/signature in
-- 'possibleHashSigAlgs' the result is Nothing, and the credential will
-- not be used to sign. This avoids a failure later in 'decideHashSig'.
signingRank cred =
case credentialDigitalSignatureAlg cred of
Just sig -> findIndex (sig `signatureCompatible`) possibleHashSigAlgs
Nothing -> Nothing
-- Finally compute credential lists and resulting cipher list.
--
-- We try to keep certificates supported by the client, but
-- fallback to all credentials if this produces no suitable result
-- (see RFC 5246 section 7.4.2 and RFC 8446 section 4.4.2.2).
-- The condition is based on resulting (EC)DHE ciphers so that
-- filtering credentials does not give advantage to a less secure
-- key exchange like CipherKeyExchange_RSA or CipherKeyExchange_DH_Anon.
cltCreds = filterCredentialsWithHashSignatures exts allCreds
sigCltCreds = filterSortCredentials signingRank cltCreds
sigAllCreds = filterSortCredentials signingRank allCreds
cltCiphers = selectCipher cltCreds sigCltCreds
allCiphers = selectCipher allCreds sigAllCreds
resultTuple = if cipherListCredentialFallback cltCiphers
then (allCreds, sigAllCreds, allCiphers)
else (cltCreds, sigCltCreds, cltCiphers)
in resultTuple
_ -> (allCreds, allCreds, selectCipher allCreds allCreds)
-- The shared cipherlist can become empty after filtering for compatible
-- creds, check now before calling onCipherChoosing, which does not handle
-- empty lists.
when (null ciphersFilteredVersion) $ throwCore $
Error_Protocol ("no cipher in common with the client", True, HandshakeFailure)
let usedCipher = onCipherChoosing (serverHooks sparams) chosenVersion ciphersFilteredVersion
cred <- case cipherKeyExchange usedCipher of
CipherKeyExchange_RSA -> return $ credentialsFindForDecrypting creds
CipherKeyExchange_DH_Anon -> return Nothing
CipherKeyExchange_DHE_RSA -> return $ credentialsFindForSigning KX_RSA signatureCreds
CipherKeyExchange_DHE_DSS -> return $ credentialsFindForSigning KX_DSS signatureCreds
CipherKeyExchange_ECDHE_RSA -> return $ credentialsFindForSigning KX_RSA signatureCreds
CipherKeyExchange_ECDHE_ECDSA -> return $ credentialsFindForSigning KX_ECDSA signatureCreds
_ -> throwCore $ Error_Protocol ("key exchange algorithm not implemented", True, HandshakeFailure)
resumeSessionData <- case clientSession of
(Session (Just clientSessionId)) ->
let resume = liftIO $ sessionResume (sharedSessionManager $ ctxShared ctx) clientSessionId
in validateSession serverName <$> resume
(Session Nothing) -> return Nothing
-- Currently, we don't send back EcPointFormats. In this case,
-- the client chooses EcPointFormat_Uncompressed.
case extensionLookup extensionID_EcPointFormats exts >>= extensionDecode MsgTClientHello of
Just (EcPointFormatsSupported fs) -> usingState_ ctx $ setClientEcPointFormatSuggest fs
_ -> return ()
doHandshake sparams cred ctx chosenVersion usedCipher usedCompression clientSession resumeSessionData exts
where
commonCiphers creds sigCreds = filter ((`elem` ciphers) . cipherID) (getCiphers sparams creds sigCreds)
commonCompressions = compressionIntersectID (supportedCompressions $ ctxSupported ctx) compressions
usedCompression = head commonCompressions
validateSession _ Nothing = Nothing
validateSession sni m@(Just sd)
-- SessionData parameters are assumed to match the local server configuration
-- so we need to compare only to ClientHello inputs. Abbreviated handshake
-- uses the same server_name than full handshake so the same
-- credentials (and thus ciphers) are available.
| clientVersion < sessionVersion sd = Nothing
| sessionCipher sd `notElem` ciphers = Nothing
| sessionCompression sd `notElem` compressions = Nothing
| isJust sni && sessionClientSNI sd /= sni = Nothing
| otherwise = m
doHandshake :: ServerParams -> Maybe Credential -> Context -> Version -> Cipher
-> Compression -> Session -> Maybe SessionData
-> [ExtensionRaw] -> IO ()
doHandshake sparams mcred ctx chosenVersion usedCipher usedCompression clientSession resumeSessionData exts = do
case resumeSessionData of
Nothing -> do
handshakeSendServerData
liftIO $ contextFlush ctx
-- Receive client info until client Finished.
recvClientData sparams ctx
sendChangeCipherAndFinish ctx ServerRole
Just sessionData -> do
usingState_ ctx (setSession clientSession True)
serverhello <- makeServerHello clientSession
sendPacket ctx $ Handshake [serverhello]
let masterSecret = sessionSecret sessionData
usingHState ctx $ setMasterSecret chosenVersion ServerRole masterSecret
logKey ctx (MasterSecret masterSecret)
sendChangeCipherAndFinish ctx ServerRole
recvChangeCipherAndFinish ctx
handshakeTerminate ctx
where
---
-- When the client sends a certificate, check whether
-- it is acceptable for the application.
--
---
makeServerHello session = do
srand <- serverRandom ctx chosenVersion $ supportedVersions $ serverSupported sparams
case mcred of
Just cred -> storePrivInfoServer ctx cred
_ -> return () -- return a sensible error
-- in TLS12, we need to check as well the certificates we are sending if they have in the extension
-- the necessary bits set.
secReneg <- usingState_ ctx getSecureRenegotiation
secRengExt <- if secReneg
then do
vf <- usingState_ ctx $ do
cvf <- getVerifiedData ClientRole
svf <- getVerifiedData ServerRole
return $ extensionEncode (SecureRenegotiation cvf $ Just svf)
return [ ExtensionRaw extensionID_SecureRenegotiation vf ]
else return []
protoExt <- applicationProtocol ctx exts sparams
sniExt <- do
resuming <- usingState_ ctx isSessionResuming
if resuming
then return []
else do
msni <- usingState_ ctx getClientSNI
case msni of
-- RFC6066: In this event, the server SHALL include
-- an extension of type "server_name" in the
-- (extended) server hello. The "extension_data"
-- field of this extension SHALL be empty.
Just _ -> return [ ExtensionRaw extensionID_ServerName ""]
Nothing -> return []
let extensions = secRengExt ++ protoExt ++ sniExt
usingState_ ctx (setVersion chosenVersion)
usingHState ctx $ setServerHelloParameters chosenVersion srand usedCipher usedCompression
return $ ServerHello chosenVersion srand session (cipherID usedCipher)
(compressionID usedCompression) extensions
handshakeSendServerData = do
serverSession <- newSession ctx
usingState_ ctx (setSession serverSession False)
serverhello <- makeServerHello serverSession
-- send ServerHello & Certificate & ServerKeyXchg & CertReq
let certMsg = case mcred of
Just (srvCerts, _) -> Certificates srvCerts
_ -> Certificates $ CertificateChain []
sendPacket ctx $ Handshake [ serverhello, certMsg ]
-- send server key exchange if needed
skx <- case cipherKeyExchange usedCipher of
CipherKeyExchange_DH_Anon -> Just <$> generateSKX_DH_Anon
CipherKeyExchange_DHE_RSA -> Just <$> generateSKX_DHE KX_RSA
CipherKeyExchange_DHE_DSS -> Just <$> generateSKX_DHE KX_DSS
CipherKeyExchange_ECDHE_RSA -> Just <$> generateSKX_ECDHE KX_RSA
CipherKeyExchange_ECDHE_ECDSA -> Just <$> generateSKX_ECDHE KX_ECDSA
_ -> return Nothing
maybe (return ()) (sendPacket ctx . Handshake . (:[]) . ServerKeyXchg) skx
-- FIXME we don't do this on a Anonymous server
-- When configured, send a certificate request with the DNs of all
-- configured CA certificates.
--
-- Client certificates MUST NOT be accepted if not requested.
--
when (serverWantClientCert sparams) $ do
usedVersion <- usingState_ ctx getVersion
let defaultCertTypes = [ CertificateType_RSA_Sign
, CertificateType_DSS_Sign
, CertificateType_ECDSA_Sign
]
(certTypes, hashSigs)
| usedVersion < TLS12 = (defaultCertTypes, Nothing)
| otherwise =
let as = supportedHashSignatures $ ctxSupported ctx
in (nub $ mapMaybe hashSigToCertType as, Just as)
creq = CertRequest certTypes hashSigs
(map extractCAname $ serverCACertificates sparams)
usingHState ctx $ setCertReqSent True
sendPacket ctx (Handshake [creq])
-- Send HelloDone
sendPacket ctx (Handshake [ServerHelloDone])
setup_DHE = do
let possibleFFGroups = negotiatedGroupsInCommon ctx exts `intersect` availableFFGroups
(dhparams, priv, pub) <-
case possibleFFGroups of
[] ->
let dhparams = fromJust "server DHE Params" $ serverDHEParams sparams
in case findFiniteFieldGroup dhparams of
Just g -> do
usingHState ctx $ setNegotiatedGroup g
generateFFDHE ctx g
Nothing -> do
(priv, pub) <- generateDHE ctx dhparams
return (dhparams, priv, pub)
g:_ -> do
usingHState ctx $ setNegotiatedGroup g
generateFFDHE ctx g
let serverParams = serverDHParamsFrom dhparams pub
usingHState ctx $ setServerDHParams serverParams
usingHState ctx $ setDHPrivate priv
return serverParams
-- Choosing a hash algorithm to sign (EC)DHE parameters
-- in ServerKeyExchange. Hash algorithm is not suggested by
-- the chosen cipher suite. So, it should be selected based on
-- the "signature_algorithms" extension in a client hello.
-- If RSA is also used for key exchange, this function is
-- not called.
decideHashSig sigAlg = do
usedVersion <- usingState_ ctx getVersion
case usedVersion of
TLS12 -> do
let hashSigs = hashAndSignaturesInCommon ctx exts
case filter (sigAlg `signatureCompatible`) hashSigs of
[] -> error ("no hash signature for " ++ show sigAlg)
x:_ -> return $ Just x
_ -> return Nothing
generateSKX_DHE kxsAlg = do
serverParams <- setup_DHE
sigAlg <- getLocalDigitalSignatureAlg ctx
mhashSig <- decideHashSig sigAlg
signed <- digitallySignDHParams ctx serverParams sigAlg mhashSig
case kxsAlg of
KX_RSA -> return $ SKX_DHE_RSA serverParams signed
KX_DSS -> return $ SKX_DHE_DSS serverParams signed
_ -> error ("generate skx_dhe unsupported key exchange signature: " ++ show kxsAlg)
generateSKX_DH_Anon = SKX_DH_Anon <$> setup_DHE
setup_ECDHE grp = do
usingHState ctx $ setNegotiatedGroup grp
(srvpri, srvpub) <- generateECDHE ctx grp
let serverParams = ServerECDHParams grp srvpub
usingHState ctx $ setServerECDHParams serverParams
usingHState ctx $ setGroupPrivate srvpri
return serverParams
generateSKX_ECDHE kxsAlg = do
let possibleECGroups = negotiatedGroupsInCommon ctx exts `intersect` availableECGroups
grp <- case possibleECGroups of
[] -> throwCore $ Error_Protocol ("no common group", True, HandshakeFailure)
g:_ -> return g
serverParams <- setup_ECDHE grp
sigAlg <- getLocalDigitalSignatureAlg ctx
mhashSig <- decideHashSig sigAlg
signed <- digitallySignECDHParams ctx serverParams sigAlg mhashSig
case kxsAlg of
KX_RSA -> return $ SKX_ECDHE_RSA serverParams signed
KX_ECDSA -> return $ SKX_ECDHE_ECDSA serverParams signed
_ -> error ("generate skx_ecdhe unsupported key exchange signature: " ++ show kxsAlg)
-- create a DigitallySigned objects for DHParams or ECDHParams.
-- | receive Client data in handshake until the Finished handshake.
--
-- <- [certificate]
-- <- client key xchg
-- <- [cert verify]
-- <- change cipher
-- <- finish
--
recvClientData :: ServerParams -> Context -> IO ()
recvClientData sparams ctx = runRecvState ctx (RecvStateHandshake processClientCertificate)
where processClientCertificate (Certificates certs) = do
clientCertificate sparams ctx certs
-- FIXME: We should check whether the certificate
-- matches our request and that we support
-- verifying with that certificate.
return $ RecvStateHandshake processClientKeyExchange
processClientCertificate p = processClientKeyExchange p
-- cannot use RecvStateHandshake, as the next message could be a ChangeCipher,
-- so we must process any packet, and in case of handshake call processHandshake manually.
processClientKeyExchange (ClientKeyXchg _) = return $ RecvStateNext processCertificateVerify
processClientKeyExchange p = unexpected (show p) (Just "client key exchange")
-- Check whether the client correctly signed the handshake.
-- If not, ask the application on how to proceed.
--
processCertificateVerify (Handshake [hs@(CertVerify dsig)]) = do
processHandshake ctx hs
certs <- checkValidClientCertChain ctx "change cipher message expected"
usedVersion <- usingState_ ctx getVersion
-- Fetch all handshake messages up to now.
msgs <- usingHState ctx $ B.concat <$> getHandshakeMessages
sigAlgExpected <- getRemoteSignatureAlg
verif <- checkCertificateVerify ctx usedVersion sigAlgExpected msgs dsig
clientCertVerify sparams ctx certs verif
return $ RecvStateNext expectChangeCipher
processCertificateVerify p = do
chain <- usingHState ctx getClientCertChain
case chain of
Just cc | isNullCertificateChain cc -> return ()
| otherwise -> throwCore $ Error_Protocol ("cert verify message missing", True, UnexpectedMessage)
Nothing -> return ()
expectChangeCipher p
getRemoteSignatureAlg = do
pk <- usingHState ctx getRemotePublicKey
case fromPubKey pk of
Nothing -> throwCore $ Error_Protocol ("unsupported remote public key type", True, HandshakeFailure)
Just sig -> return sig
expectChangeCipher ChangeCipherSpec = do
return $ RecvStateHandshake expectFinish
expectChangeCipher p = unexpected (show p) (Just "change cipher")
expectFinish (Finished _) = return RecvStateDone
expectFinish p = unexpected (show p) (Just "Handshake Finished")
checkValidClientCertChain :: MonadIO m => Context -> String -> m CertificateChain
checkValidClientCertChain ctx errmsg = do
chain <- usingHState ctx getClientCertChain
let throwerror = Error_Protocol (errmsg , True, UnexpectedMessage)
case chain of
Nothing -> throwCore throwerror
Just cc | isNullCertificateChain cc -> throwCore throwerror
| otherwise -> return cc
hashAndSignaturesInCommon :: Context -> [ExtensionRaw] -> [HashAndSignatureAlgorithm]
hashAndSignaturesInCommon ctx exts =
let cHashSigs = case extensionLookup extensionID_SignatureAlgorithms exts >>= extensionDecode MsgTClientHello of
-- See Section 7.4.1.4.1 of RFC 5246.
Nothing -> [(HashSHA1, SignatureECDSA)
,(HashSHA1, SignatureRSA)
,(HashSHA1, SignatureDSS)]
Just (SignatureAlgorithms sas) -> sas
sHashSigs = supportedHashSignatures $ ctxSupported ctx
-- The values in the "signature_algorithms" extension
-- are in descending order of preference.
-- However here the algorithms are selected according
-- to server preference in 'supportedHashSignatures'.
in sHashSigs `intersect` cHashSigs
negotiatedGroupsInCommon :: Context -> [ExtensionRaw] -> [Group]
negotiatedGroupsInCommon ctx exts = case extensionLookup extensionID_NegotiatedGroups exts >>= extensionDecode MsgTClientHello of
Just (NegotiatedGroups clientGroups) ->
let serverGroups = supportedGroups (ctxSupported ctx)
in serverGroups `intersect` clientGroups
_ -> []
credentialDigitalSignatureAlg :: Credential -> Maybe DigitalSignatureAlg
credentialDigitalSignatureAlg cred =
findDigitalSignatureAlg (credentialPublicPrivateKeys cred)
filterSortCredentials :: Ord a => (Credential -> Maybe a) -> Credentials -> Credentials
filterSortCredentials rankFun (Credentials creds) =
let orderedPairs = sortOn fst [ (rankFun cred, cred) | cred <- creds ]
in Credentials [ cred | (Just _, cred) <- orderedPairs ]
-- Filters a list of candidate credentials with credentialMatchesHashSignatures.
--
-- Algorithms to filter with are taken from "signature_algorithms_cert"
-- extension when it exists, else from "signature_algorithms" when clients do
-- not implement the new extension (see RFC 8446 section 4.2.3).
--
-- Resulting credential list can be used as input to the hybrid cipher-and-
-- certificate selection for TLS12, or to the direct certificate selection
-- simplified with TLS13. As filtering credential signatures with client-
-- advertised algorithms is not supposed to cause negotiation failure, in case
-- of dead end with the subsequent selection process, this process should always
-- be restarted with the unfiltered credential list as input (see fallback
-- certificate chains, described in same RFC section).
--
-- Calling code should not forget to apply constraints of extension
-- "signature_algorithms" to any signature-based key exchange derived from the
-- output credentials. Respecting client constraints on KX signatures is
-- mandatory but not implemented by this function.
filterCredentialsWithHashSignatures :: [ExtensionRaw] -> Credentials -> Credentials
filterCredentialsWithHashSignatures exts =
case withExt extensionID_SignatureAlgorithmsCert of
Just (SignatureAlgorithmsCert sas) -> withAlgs sas
Nothing ->
case withExt extensionID_SignatureAlgorithms of
Nothing -> id
Just (SignatureAlgorithms sas) -> withAlgs sas
where
withExt extId = extensionLookup extId exts >>= extensionDecode MsgTClientHello
withAlgs sas = filterCredentials (credentialMatchesHashSignatures sas)
filterCredentials p (Credentials l) = Credentials (filter p l)
-- returns True if certificate filtering with "signature_algorithms_cert" /
-- "signature_algorithms" produced no ephemeral D-H nor TLS13 cipher (so
-- handshake with lower security)
cipherListCredentialFallback :: [Cipher] -> Bool
cipherListCredentialFallback = all nonDH
where
nonDH x = case cipherKeyExchange x of
CipherKeyExchange_DHE_RSA -> False
CipherKeyExchange_DHE_DSS -> False
CipherKeyExchange_ECDHE_RSA -> False
CipherKeyExchange_ECDHE_ECDSA -> False
CipherKeyExchange_TLS13 -> False
_ -> True
storePrivInfoServer :: MonadIO m => Context -> Credential -> m ()
storePrivInfoServer ctx (cc, privkey) = void (storePrivInfo ctx cc privkey)
-- TLS 1.3 or later
handshakeServerWithTLS13 :: ServerParams
-> Context
-> Version
-> Credentials
-> [ExtensionRaw]
-> [CipherID]
-> Maybe String
-> Session
-> IO ()
handshakeServerWithTLS13 sparams ctx chosenVersion allCreds exts clientCiphers _serverName clientSession = do
when (any (\(ExtensionRaw eid _) -> eid == extensionID_PreSharedKey) $ init exts) $
throwCore $ Error_Protocol ("extension pre_shared_key must be last", True, IllegalParameter)
-- Deciding cipher.
-- The shared cipherlist can become empty after filtering for compatible
-- creds, check now before calling onCipherChoosing, which does not handle
-- empty lists.
when (null ciphersFilteredVersion) $ throwCore $
Error_Protocol ("no cipher in common with the client", True, HandshakeFailure)
let usedCipher = onCipherChoosing (serverHooks sparams) chosenVersion ciphersFilteredVersion
usedHash = cipherHash usedCipher
rtt0 = case extensionLookup extensionID_EarlyData exts >>= extensionDecode MsgTClientHello of
Just (EarlyDataIndication _) -> True
Nothing -> False
when rtt0 $
-- mark a 0-RTT attempt before a possible HRR, and before updating the
-- status again if 0-RTT successful
setEstablished ctx (EarlyDataNotAllowed 3) -- hardcoding
-- Deciding key exchange from key shares
keyShares <- case extensionLookup extensionID_KeyShare exts >>= extensionDecode MsgTClientHello of
Just (KeyShareClientHello kses) -> return kses
Just _ -> error "handshakeServerWithTLS13: invalid KeyShare value"
_ -> throwCore $ Error_Protocol ("key exchange not implemented, expected key_share extension", True, HandshakeFailure)
case findKeyShare keyShares serverGroups of
Nothing -> helloRetryRequest sparams ctx chosenVersion usedCipher exts serverGroups clientSession
Just keyShare -> doHandshake13 sparams ctx allCreds chosenVersion usedCipher exts usedHash keyShare clientSession rtt0
where
ciphersFilteredVersion = filter ((`elem` clientCiphers) . cipherID) serverCiphers
serverCiphers = filter (cipherAllowedForVersion chosenVersion) (supportedCiphers $ serverSupported sparams)
serverGroups = supportedGroups (ctxSupported ctx)
findKeyShare _ [] = Nothing
findKeyShare ks (g:gs) = case find (\ent -> keyShareEntryGroup ent == g) ks of
Just k -> Just k
Nothing -> findKeyShare ks gs
doHandshake13 :: ServerParams -> Context -> Credentials -> Version
-> Cipher -> [ExtensionRaw]
-> Hash -> KeyShareEntry
-> Session -> Bool
-> IO ()
doHandshake13 sparams ctx allCreds chosenVersion usedCipher exts usedHash clientKeyShare clientSession rtt0 = do
newSession ctx >>= \ss -> usingState_ ctx $ do
setSession ss False
setClientSupportsPHA supportsPHA
usingHState ctx $ setNegotiatedGroup $ keyShareEntryGroup clientKeyShare
srand <- setServerParameter
(psk, binderInfo, is0RTTvalid) <- choosePSK
hCh <- transcriptHash ctx
let earlySecret = hkdfExtract usedHash zero psk
clientEarlyTrafficSecret = deriveSecret usedHash earlySecret "c e traffic" hCh
logKey ctx (ClientEarlyTrafficSecret clientEarlyTrafficSecret)
extensions <- checkBinder earlySecret binderInfo
hrr <- usingState_ ctx getTLS13HRR
let authenticated = isJust binderInfo
rtt0OK = authenticated && not hrr && rtt0 && rtt0accept && is0RTTvalid
----------------------------------------------------------------
established <- ctxEstablished ctx
if established /= NotEstablished then
if rtt0OK then do
usingHState ctx $ setTLS13HandshakeMode RTT0
usingHState ctx $ setTLS13RTT0Status RTT0Accepted
else do
usingHState ctx $ setTLS13HandshakeMode RTT0
usingHState ctx $ setTLS13RTT0Status RTT0Rejected
else
if authenticated then
usingHState ctx $ setTLS13HandshakeMode PreSharedKey
else
-- FullHandshake or HelloRetryRequest
return ()
mCredInfo <- if authenticated then return Nothing else decideCredentialInfo
(ecdhe,keyShare) <- makeServerKeyShare ctx clientKeyShare
ensureRecvComplete ctx
let handshakeSecret = hkdfExtract usedHash (deriveSecret usedHash earlySecret "derived" (hash usedHash "")) ecdhe
clientHandshakeTrafficSecret <- runPacketFlight ctx $ do
sendServerHello keyShare srand extensions
sendChangeCipherSpec13 ctx
----------------------------------------------------------------
hChSh <- transcriptHash ctx
let clientHandshakeTrafficSecret = deriveSecret usedHash handshakeSecret "c hs traffic" hChSh
serverHandshakeTrafficSecret = deriveSecret usedHash handshakeSecret "s hs traffic" hChSh
liftIO $ do
logKey ctx (ServerHandshakeTrafficSecret serverHandshakeTrafficSecret)
logKey ctx (ClientHandshakeTrafficSecret clientHandshakeTrafficSecret)
setRxState ctx usedHash usedCipher $ if rtt0OK then clientEarlyTrafficSecret else clientHandshakeTrafficSecret
setTxState ctx usedHash usedCipher serverHandshakeTrafficSecret
----------------------------------------------------------------
sendExtensions rtt0OK
case mCredInfo of
Nothing -> return ()
Just (cred, hashSig) -> sendCertAndVerify cred hashSig
rawFinished <- makeFinished ctx usedHash serverHandshakeTrafficSecret
loadPacket13 ctx $ Handshake13 [rawFinished]
return clientHandshakeTrafficSecret
sfSentTime <- getCurrentTimeFromBase
----------------------------------------------------------------
let masterSecret = hkdfExtract usedHash (deriveSecret usedHash handshakeSecret "derived" (hash usedHash "")) zero
hChSf <- transcriptHash ctx
let clientApplicationTrafficSecret0 = deriveSecret usedHash masterSecret "c ap traffic" hChSf
serverApplicationTrafficSecret0 = deriveSecret usedHash masterSecret "s ap traffic" hChSf
exporterMasterSecret = deriveSecret usedHash masterSecret "exp master" hChSf
usingState_ ctx $ setExporterMasterSecret exporterMasterSecret
----------------------------------------------------------------
logKey ctx (ServerTrafficSecret0 serverApplicationTrafficSecret0)
logKey ctx (ClientTrafficSecret0 clientApplicationTrafficSecret0)
setTxState ctx usedHash usedCipher serverApplicationTrafficSecret0
----------------------------------------------------------------
if rtt0OK then
setEstablished ctx (EarlyDataAllowed rtt0max)
else when (established == NotEstablished) $
setEstablished ctx (EarlyDataNotAllowed 3) -- hardcoding
let expectFinished hChBeforeCf (Finished13 verifyData) = liftIO $ do
checkFinished usedHash clientHandshakeTrafficSecret hChBeforeCf verifyData
handshakeTerminate13 ctx
setRxState ctx usedHash usedCipher clientApplicationTrafficSecret0
sendNewSessionTicket masterSecret sfSentTime
expectFinished _ hs = unexpected (show hs) (Just "finished 13")
let expectEndOfEarlyData EndOfEarlyData13 =
setRxState ctx usedHash usedCipher clientHandshakeTrafficSecret
expectEndOfEarlyData hs = unexpected (show hs) (Just "end of early data")
if not authenticated && serverWantClientCert sparams then
runRecvHandshake13 $ do
skip <- recvHandshake13 ctx expectCertificate
unless skip $ recvHandshake13hash ctx (expectCertVerify sparams ctx)
recvHandshake13hash ctx expectFinished
ensureRecvComplete ctx
else if rtt0OK then
setPendingActions ctx [PendingAction True expectEndOfEarlyData
,PendingActionHash True expectFinished]
else
runRecvHandshake13 $ do
recvHandshake13hash ctx expectFinished
ensureRecvComplete ctx
where
setServerParameter = do
srand <- serverRandom ctx chosenVersion $ supportedVersions $ serverSupported sparams
usingState_ ctx $ setVersion chosenVersion
failOnEitherError $ usingHState ctx $ setHelloParameters13 usedCipher
return srand
supportsPHA = case extensionLookup extensionID_PostHandshakeAuth exts >>= extensionDecode MsgTClientHello of
Just PostHandshakeAuth -> True
Nothing -> False
choosePSK = case extensionLookup extensionID_PreSharedKey exts >>= extensionDecode MsgTClientHello of
Just (PreSharedKeyClientHello (PskIdentity sessionId obfAge:_) bnds@(bnd:_)) -> do
when (null dhModes) $
throwCore $ Error_Protocol ("no psk_key_exchange_modes extension", True, MissingExtension)
if PSK_DHE_KE `elem` dhModes then do
let len = sum (map (\x -> B.length x + 1) bnds) + 2
mgr = sharedSessionManager $ serverShared sparams
msdata <- if rtt0 then sessionResumeOnlyOnce mgr sessionId
else sessionResume mgr sessionId
case msdata of
Just sdata -> do
let Just tinfo = sessionTicketInfo sdata
psk = sessionSecret sdata
isFresh <- checkFreshness tinfo obfAge
(isPSKvalid, is0RTTvalid) <- checkSessionEquality sdata
if isPSKvalid && isFresh then
return (psk, Just (bnd,0::Int,len),is0RTTvalid)
else
-- fall back to full handshake
return (zero, Nothing, False)
_ -> return (zero, Nothing, False)
else return (zero, Nothing, False)
_ -> return (zero, Nothing, False)
checkSessionEquality sdata = do
msni <- usingState_ ctx getClientSNI
malpn <- usingState_ ctx getNegotiatedProtocol
let isSameSNI = sessionClientSNI sdata == msni
isSameCipher = sessionCipher sdata == cipherID usedCipher
ciphers = supportedCiphers $ serverSupported sparams
isSameKDF = case find (\c -> cipherID c == sessionCipher sdata) ciphers of
Nothing -> False
Just c -> cipherHash c == cipherHash usedCipher
isSameVersion = chosenVersion == sessionVersion sdata
isSameALPN = sessionALPN sdata == malpn
isPSKvalid = isSameKDF && isSameSNI -- fixme: SNI is not required
is0RTTvalid = isSameVersion && isSameCipher && isSameALPN
return (isPSKvalid, is0RTTvalid)
rtt0max = safeNonNegative32 $ serverEarlyDataSize sparams
rtt0accept = serverEarlyDataSize sparams > 0
checkBinder _ Nothing = return []
checkBinder earlySecret (Just (binder,n,tlen)) = do
binder' <- makePSKBinder ctx earlySecret usedHash tlen Nothing
unless (binder `bytesEq` binder') $
decryptError "PSK binder validation failed"
let selectedIdentity = extensionEncode $ PreSharedKeyServerHello $ fromIntegral n
return [ExtensionRaw extensionID_PreSharedKey selectedIdentity]
decideCredentialInfo = do
cHashSigs <- case extensionLookup extensionID_SignatureAlgorithms exts >>= extensionDecode MsgTClientHello of
Nothing -> throwCore $ Error_Protocol ("no signature_algorithms extension", True, MissingExtension)
Just (SignatureAlgorithms sas) -> return sas
-- When deciding signature algorithm and certificate, we try to keep
-- certificates supported by the client, but fallback to all credentials
-- if this produces no suitable result (see RFC 5246 section 7.4.2 and
-- RFC 8446 section 4.4.2.2).
let sHashSigs = filter isHashSignatureValid13 $ supportedHashSignatures $ ctxSupported ctx
hashSigs = sHashSigs `intersect` cHashSigs
cltCreds = filterCredentialsWithHashSignatures exts allCreds
case credentialsFindForSigning13 hashSigs cltCreds of
Nothing ->
case credentialsFindForSigning13 hashSigs allCreds of
Nothing -> throwCore $ Error_Protocol ("credential not found", True, HandshakeFailure)
mcs -> return mcs
mcs -> return mcs
sendServerHello keyShare srand extensions = do
let serverKeyShare = extensionEncode $ KeyShareServerHello keyShare
selectedVersion = extensionEncode $ SupportedVersionsServerHello chosenVersion
extensions' = ExtensionRaw extensionID_KeyShare serverKeyShare
: ExtensionRaw extensionID_SupportedVersions selectedVersion
: extensions
helo = ServerHello13 srand clientSession (cipherID usedCipher) extensions'
loadPacket13 ctx $ Handshake13 [helo]
sendCertAndVerify cred@(certChain, _) hashSig = do
storePrivInfoServer ctx cred
when (serverWantClientCert sparams) $ do
let certReqCtx = "" -- this must be zero length here.
certReq = makeCertRequest sparams ctx certReqCtx
loadPacket13 ctx $ Handshake13 [certReq]
usingHState ctx $ setCertReqSent True
let CertificateChain cs = certChain
ess = replicate (length cs) []
loadPacket13 ctx $ Handshake13 [Certificate13 "" certChain ess]
hChSc <- transcriptHash ctx
sigAlg <- getLocalDigitalSignatureAlg ctx
vrfy <- makeCertVerify ctx sigAlg hashSig hChSc
loadPacket13 ctx $ Handshake13 [vrfy]
sendExtensions rtt0OK = do
protoExt <- liftIO $ applicationProtocol ctx exts sparams
msni <- liftIO $ usingState_ ctx getClientSNI
let sniExtension = case msni of
-- RFC6066: In this event, the server SHALL include
-- an extension of type "server_name" in the
-- (extended) server hello. The "extension_data"
-- field of this extension SHALL be empty.
Just _ -> Just $ ExtensionRaw extensionID_ServerName ""
Nothing -> Nothing
mgroup <- usingHState ctx getNegotiatedGroup
let serverGroups = supportedGroups (ctxSupported ctx)
groupExtension
| null serverGroups = Nothing
| maybe True (== head serverGroups) mgroup = Nothing
| otherwise = Just $ ExtensionRaw extensionID_NegotiatedGroups $ extensionEncode (NegotiatedGroups serverGroups)
let earlyDataExtension
| rtt0OK = Just $ ExtensionRaw extensionID_EarlyData $ extensionEncode (EarlyDataIndication Nothing)
| otherwise = Nothing
let extensions = catMaybes [earlyDataExtension, groupExtension, sniExtension] ++ protoExt
loadPacket13 ctx $ Handshake13 [EncryptedExtensions13 extensions]
sendNewSessionTicket masterSecret sfSentTime = when sendNST $ do
cfRecvTime <- getCurrentTimeFromBase
let rtt = cfRecvTime - sfSentTime
hChCf <- transcriptHash ctx
nonce <- getStateRNG ctx 32
let resumptionMasterSecret = deriveSecret usedHash masterSecret "res master" hChCf
life = toSeconds $ serverTicketLifetime sparams
psk = hkdfExpandLabel usedHash resumptionMasterSecret "resumption" nonce hashSize
(label, add) <- generateSession life psk rtt0max rtt
let nst = createNewSessionTicket life add nonce label rtt0max
sendPacket13 ctx $ Handshake13 [nst]
where
sendNST = PSK_DHE_KE `elem` dhModes
generateSession life psk maxSize rtt = do
Session (Just sessionId) <- newSession ctx
tinfo <- createTLS13TicketInfo life (Left ctx) (Just rtt)
sdata <- getSessionData13 ctx usedCipher tinfo maxSize psk
let mgr = sharedSessionManager $ serverShared sparams
sessionEstablish mgr sessionId sdata
return (sessionId, ageAdd tinfo)
createNewSessionTicket life add nonce label maxSize =
NewSessionTicket13 life add nonce label extensions
where
tedi = extensionEncode $ EarlyDataIndication $ Just $ fromIntegral maxSize
extensions = [ExtensionRaw extensionID_EarlyData tedi]
toSeconds i | i < 0 = 0
| i > 604800 = 604800
| otherwise = fromIntegral i
dhModes = case extensionLookup extensionID_PskKeyExchangeModes exts >>= extensionDecode MsgTClientHello of
Just (PskKeyExchangeModes ms) -> ms
Nothing -> []
expectCertificate :: Handshake13 -> RecvHandshake13M IO Bool
expectCertificate (Certificate13 certCtx certs _ext) = liftIO $ do
when (certCtx /= "") $ throwCore $ Error_Protocol ("certificate request context MUST be empty", True, IllegalParameter)
-- fixme checking _ext
clientCertificate sparams ctx certs
return $ isNullCertificateChain certs
expectCertificate hs = unexpected (show hs) (Just "certificate 13")
hashSize = hashDigestSize usedHash
zero = B.replicate hashSize 0
expectCertVerify :: MonadIO m => ServerParams -> Context -> ByteString -> Handshake13 -> m ()
expectCertVerify sparams ctx hChCc (CertVerify13 sigAlg sig) = liftIO $ do
certs@(CertificateChain cc) <- checkValidClientCertChain ctx "finished 13 message expected"
pubkey <- case cc of
[] -> throwCore $ Error_Protocol ("client certificate missing", True, HandshakeFailure)
c:_ -> return $ certPubKey $ getCertificate c
usingHState ctx $ setPublicKey pubkey
let keyAlg = fromJust "fromPubKey" (fromPubKey pubkey)
verif <- checkCertVerify ctx keyAlg sigAlg sig hChCc
clientCertVerify sparams ctx certs verif
expectCertVerify _ _ _ hs = unexpected (show hs) (Just "certificate verify 13")
helloRetryRequest :: MonadIO m => ServerParams -> Context -> Version -> Cipher -> [ExtensionRaw] -> [Group] -> Session -> m ()
helloRetryRequest sparams ctx chosenVersion usedCipher exts serverGroups clientSession = liftIO $ do
twice <- usingState_ ctx getTLS13HRR
when twice $
throwCore $ Error_Protocol ("Hello retry not allowed again", True, HandshakeFailure)
usingState_ ctx $ setTLS13HRR True
failOnEitherError $ usingHState ctx $ setHelloParameters13 usedCipher
let clientGroups = case extensionLookup extensionID_NegotiatedGroups exts >>= extensionDecode MsgTClientHello of
Just (NegotiatedGroups gs) -> gs
Nothing -> []
possibleGroups = serverGroups `intersect` clientGroups
case possibleGroups of
[] -> throwCore $ Error_Protocol ("no group in common with the client for HRR", True, HandshakeFailure)
g:_ -> do
let serverKeyShare = extensionEncode $ KeyShareHRR g
selectedVersion = extensionEncode $ SupportedVersionsServerHello chosenVersion
extensions = [ExtensionRaw extensionID_KeyShare serverKeyShare
,ExtensionRaw extensionID_SupportedVersions selectedVersion]
hrr = ServerHello13 hrrRandom clientSession (cipherID usedCipher) extensions
usingHState ctx $ setTLS13HandshakeMode HelloRetryRequest
runPacketFlight ctx $ do
loadPacket13 ctx $ Handshake13 [hrr]
sendChangeCipherSpec13 ctx
handshakeServer sparams ctx
findHighestVersionFrom :: Version -> [Version] -> Maybe Version
findHighestVersionFrom clientVersion allowedVersions =
case filter (clientVersion >=) $ sortOn Down allowedVersions of
[] -> Nothing
v:_ -> Just v
-- We filter our allowed ciphers here according to dynamic credential lists.
-- Credentials 'creds' come from server parameters but also SNI callback.
-- When the key exchange requires a signature, we use a
-- subset of this list named 'sigCreds'. This list has been filtered in order
-- to remove certificates that are not compatible with hash/signature
-- restrictions (TLS 1.2).
getCiphers :: ServerParams -> Credentials -> Credentials -> [Cipher]
getCiphers sparams creds sigCreds = filter authorizedCKE (supportedCiphers $ serverSupported sparams)
where authorizedCKE cipher =
case cipherKeyExchange cipher of
CipherKeyExchange_RSA -> canEncryptRSA
CipherKeyExchange_DH_Anon -> True
CipherKeyExchange_DHE_RSA -> canSignRSA
CipherKeyExchange_DHE_DSS -> canSignDSS
CipherKeyExchange_ECDHE_RSA -> canSignRSA
CipherKeyExchange_ECDHE_ECDSA -> canSignECDSA
-- unimplemented: non ephemeral DH & ECDH.
-- Note, these *should not* be implemented, and have
-- (for example) been removed in OpenSSL 1.1.0
--
CipherKeyExchange_DH_DSS -> False
CipherKeyExchange_DH_RSA -> False
CipherKeyExchange_ECDH_ECDSA -> False
CipherKeyExchange_ECDH_RSA -> False
CipherKeyExchange_TLS13 -> False -- not reached
canSignDSS = KX_DSS `elem` signingAlgs
canSignRSA = KX_RSA `elem` signingAlgs
canSignECDSA = KX_ECDSA `elem` signingAlgs
canEncryptRSA = isJust $ credentialsFindForDecrypting creds
signingAlgs = credentialsListSigningAlgorithms sigCreds
findHighestVersionFrom13 :: [Version] -> [Version] -> Maybe Version
findHighestVersionFrom13 clientVersions serverVersions = case svs `intersect` cvs of
[] -> Nothing
v:_ -> Just v
where
svs = sortOn Down serverVersions
cvs = sortOn Down clientVersions
applicationProtocol :: Context -> [ExtensionRaw] -> ServerParams -> IO [ExtensionRaw]
applicationProtocol ctx exts sparams
| clientALPNSuggest = do
suggest <- usingState_ ctx getClientALPNSuggest
case (onALPNClientSuggest $ serverHooks sparams, suggest) of
(Just io, Just protos) -> do
proto <- io protos
usingState_ ctx $ do
setExtensionALPN True
setNegotiatedProtocol proto
return [ ExtensionRaw extensionID_ApplicationLayerProtocolNegotiation
(extensionEncode $ ApplicationLayerProtocolNegotiation [proto]) ]
(_, _) -> return []
| otherwise = return []
where
clientALPNSuggest = isJust $ extensionLookup extensionID_ApplicationLayerProtocolNegotiation exts
credentialsFindForSigning13 :: [HashAndSignatureAlgorithm] -> Credentials -> Maybe (Credential, HashAndSignatureAlgorithm)
credentialsFindForSigning13 hss0 creds = loop hss0
where
loop [] = Nothing
loop (hs:hss) = case credentialsFindForSigning13' hs creds of
Nothing -> credentialsFindForSigning13 hss creds
Just cred -> Just (cred, hs)
-- See credentialsFindForSigning.
credentialsFindForSigning13' :: HashAndSignatureAlgorithm -> Credentials -> Maybe Credential
credentialsFindForSigning13' sigAlg (Credentials l) = find forSigning l
where
forSigning cred = case credentialDigitalSignatureAlg cred of
Nothing -> False
Just sig -> sig `signatureCompatible` sigAlg
clientCertificate :: ServerParams -> Context -> CertificateChain -> IO ()
clientCertificate sparams ctx certs = do
-- run certificate recv hook
ctxWithHooks ctx (`hookRecvCertificates` certs)
-- Call application callback to see whether the
-- certificate chain is acceptable.
--
usage <- liftIO $ catchException (onClientCertificate (serverHooks sparams) certs) rejectOnException
case usage of
CertificateUsageAccept -> verifyLeafKeyUsage [KeyUsage_digitalSignature] certs
CertificateUsageReject reason -> certificateRejected reason
-- Remember cert chain for later use.
--
usingHState ctx $ setClientCertChain certs
clientCertVerify :: ServerParams -> Context -> CertificateChain -> Bool -> IO ()
clientCertVerify sparams ctx certs verif = do
if verif then do
-- When verification succeeds, commit the
-- client certificate chain to the context.
--
usingState_ ctx $ setClientCertificateChain certs
return ()
else do
-- Either verification failed because of an
-- invalid format (with an error message), or
-- the signature is wrong. In either case,
-- ask the application if it wants to
-- proceed, we will do that.
res <- liftIO $ onUnverifiedClientCert (serverHooks sparams)
if res then do
-- When verification fails, but the
-- application callbacks accepts, we
-- also commit the client certificate
-- chain to the context.
usingState_ ctx $ setClientCertificateChain certs
else decryptError "verification failed"
newCertReqContext :: Context -> IO CertReqContext
newCertReqContext ctx = getStateRNG ctx 32
requestCertificateServer :: ServerParams -> Context -> IO Bool
requestCertificateServer sparams ctx = do
tls13 <- tls13orLater ctx
supportsPHA <- usingState_ ctx getClientSupportsPHA
let ok = tls13 && supportsPHA
when ok $ do
certReqCtx <- newCertReqContext ctx
let certReq = makeCertRequest sparams ctx certReqCtx
bracket (saveHState ctx) (restoreHState ctx) $ \_ -> do
addCertRequest13 ctx certReq
sendPacket13 ctx $ Handshake13 [certReq]
return ok
postHandshakeAuthServerWith :: ServerParams -> Context -> Handshake13 -> IO ()
postHandshakeAuthServerWith sparams ctx h@(Certificate13 certCtx certs _ext) = do
mCertReq <- getCertRequest13 ctx certCtx
when (isNothing mCertReq) $ throwCore $ Error_Protocol ("unknown certificate request context", True, DecodeError)
let certReq = fromJust "certReq" mCertReq
-- fixme checking _ext
clientCertificate sparams ctx certs
baseHState <- saveHState ctx
processHandshake13 ctx certReq
processHandshake13 ctx h
(usedHash, _, applicationTrafficSecretN) <- getRxState ctx
let expectFinished hChBeforeCf (Finished13 verifyData) = do
checkFinished usedHash applicationTrafficSecretN hChBeforeCf verifyData
void $ restoreHState ctx baseHState
expectFinished _ hs = unexpected (show hs) (Just "finished 13")
-- Note: here the server could send updated NST too, however the library
-- currently has no API to handle resumption and client authentication
-- together, see discussion in #133
if isNullCertificateChain certs
then setPendingActions ctx [ PendingActionHash False expectFinished ]
else setPendingActions ctx [ PendingActionHash False (expectCertVerify sparams ctx)
, PendingActionHash False expectFinished
]
postHandshakeAuthServerWith _ _ _ =
throwCore $ Error_Protocol ("unexpected handshake message received in postHandshakeAuthServerWith", True, UnexpectedMessage)