boringssl/ssl/test/runner/common.go
David Benjamin af56fbd62a Renumber TLS 1.3 signature algorithms.
The old numbers violate a MUST-level requirement in TLS 1.2 to not
advertise anonymous (0x0700 ends in 0x00). The spec has been updated
with new allocations which avoid these.

BUG=webrtc:6342

Change-Id: Ia5663ada98fa1ebf0f8a7f50fe74a0e9206c4194
Reviewed-on: https://boringssl-review.googlesource.com/11131
Reviewed-by: Adam Langley <agl@google.com>
2016-09-21 20:54:15 +00:00

1476 lines
49 KiB
Go

// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package runner
import (
"container/list"
"crypto"
"crypto/ecdsa"
"crypto/rand"
"crypto/x509"
"fmt"
"io"
"math/big"
"strings"
"sync"
"time"
)
const (
VersionSSL30 = 0x0300
VersionTLS10 = 0x0301
VersionTLS11 = 0x0302
VersionTLS12 = 0x0303
VersionTLS13 = 0x0304
)
// The draft version of TLS 1.3 that is implemented here and sent in the draft
// indicator extension.
const tls13DraftVersion = 14
const (
maxPlaintext = 16384 // maximum plaintext payload length
maxCiphertext = 16384 + 2048 // maximum ciphertext payload length
tlsRecordHeaderLen = 5 // record header length
dtlsRecordHeaderLen = 13
maxHandshake = 65536 // maximum handshake we support (protocol max is 16 MB)
minVersion = VersionSSL30
maxVersion = VersionTLS13
)
// TLS record types.
type recordType uint8
const (
recordTypeChangeCipherSpec recordType = 20
recordTypeAlert recordType = 21
recordTypeHandshake recordType = 22
recordTypeApplicationData recordType = 23
)
// TLS handshake message types.
const (
typeHelloRequest uint8 = 0
typeClientHello uint8 = 1
typeServerHello uint8 = 2
typeHelloVerifyRequest uint8 = 3
typeNewSessionTicket uint8 = 4
typeHelloRetryRequest uint8 = 6 // draft-ietf-tls-tls13-13
typeEncryptedExtensions uint8 = 8 // draft-ietf-tls-tls13-13
typeCertificate uint8 = 11
typeServerKeyExchange uint8 = 12
typeCertificateRequest uint8 = 13
typeServerHelloDone uint8 = 14
typeCertificateVerify uint8 = 15
typeClientKeyExchange uint8 = 16
typeFinished uint8 = 20
typeCertificateStatus uint8 = 22
typeKeyUpdate uint8 = 24 // draft-ietf-tls-tls13-13
typeNextProtocol uint8 = 67 // Not IANA assigned
typeChannelID uint8 = 203 // Not IANA assigned
)
// TLS compression types.
const (
compressionNone uint8 = 0
)
// TLS extension numbers
const (
extensionServerName uint16 = 0
extensionStatusRequest uint16 = 5
extensionSupportedCurves uint16 = 10
extensionSupportedPoints uint16 = 11
extensionSignatureAlgorithms uint16 = 13
extensionUseSRTP uint16 = 14
extensionALPN uint16 = 16
extensionSignedCertificateTimestamp uint16 = 18
extensionExtendedMasterSecret uint16 = 23
extensionSessionTicket uint16 = 35
extensionKeyShare uint16 = 40 // draft-ietf-tls-tls13-13
extensionPreSharedKey uint16 = 41 // draft-ietf-tls-tls13-13
extensionEarlyData uint16 = 42 // draft-ietf-tls-tls13-13
extensionCookie uint16 = 44 // draft-ietf-tls-tls13-13
extensionCustom uint16 = 1234 // not IANA assigned
extensionNextProtoNeg uint16 = 13172 // not IANA assigned
extensionRenegotiationInfo uint16 = 0xff01
extensionTLS13Draft uint16 = 0xff02
extensionChannelID uint16 = 30032 // not IANA assigned
)
// TLS signaling cipher suite values
const (
scsvRenegotiation uint16 = 0x00ff
)
// CurveID is the type of a TLS identifier for an elliptic curve. See
// http://www.iana.org/assignments/tls-parameters/tls-parameters.xml#tls-parameters-8
type CurveID uint16
const (
CurveP224 CurveID = 21
CurveP256 CurveID = 23
CurveP384 CurveID = 24
CurveP521 CurveID = 25
CurveX25519 CurveID = 29
)
// TLS Elliptic Curve Point Formats
// http://www.iana.org/assignments/tls-parameters/tls-parameters.xml#tls-parameters-9
const (
pointFormatUncompressed uint8 = 0
)
// TLS CertificateStatusType (RFC 3546)
const (
statusTypeOCSP uint8 = 1
)
// Certificate types (for certificateRequestMsg)
const (
CertTypeRSASign = 1 // A certificate containing an RSA key
CertTypeDSSSign = 2 // A certificate containing a DSA key
CertTypeRSAFixedDH = 3 // A certificate containing a static DH key
CertTypeDSSFixedDH = 4 // A certificate containing a static DH key
// See RFC4492 sections 3 and 5.5.
CertTypeECDSASign = 64 // A certificate containing an ECDSA-capable public key, signed with ECDSA.
CertTypeRSAFixedECDH = 65 // A certificate containing an ECDH-capable public key, signed with RSA.
CertTypeECDSAFixedECDH = 66 // A certificate containing an ECDH-capable public key, signed with ECDSA.
// Rest of these are reserved by the TLS spec
)
// signatureAlgorithm corresponds to a SignatureScheme value from TLS 1.3. Note
// that TLS 1.3 names the production 'SignatureScheme' to avoid colliding with
// TLS 1.2's SignatureAlgorithm but otherwise refers to them as 'signature
// algorithms' throughout. We match the latter.
type signatureAlgorithm uint16
const (
// RSASSA-PKCS1-v1_5 algorithms
signatureRSAPKCS1WithMD5 signatureAlgorithm = 0x0101
signatureRSAPKCS1WithSHA1 signatureAlgorithm = 0x0201
signatureRSAPKCS1WithSHA256 signatureAlgorithm = 0x0401
signatureRSAPKCS1WithSHA384 signatureAlgorithm = 0x0501
signatureRSAPKCS1WithSHA512 signatureAlgorithm = 0x0601
// ECDSA algorithms
signatureECDSAWithSHA1 signatureAlgorithm = 0x0203
signatureECDSAWithP256AndSHA256 signatureAlgorithm = 0x0403
signatureECDSAWithP384AndSHA384 signatureAlgorithm = 0x0503
signatureECDSAWithP521AndSHA512 signatureAlgorithm = 0x0603
// RSASSA-PSS algorithms
signatureRSAPSSWithSHA256 signatureAlgorithm = 0x0804
signatureRSAPSSWithSHA384 signatureAlgorithm = 0x0805
signatureRSAPSSWithSHA512 signatureAlgorithm = 0x0806
// EdDSA algorithms
signatureEd25519 signatureAlgorithm = 0x0807
signatureEd448 signatureAlgorithm = 0x0808
)
// supportedSignatureAlgorithms contains the default supported signature
// algorithms.
var supportedSignatureAlgorithms = []signatureAlgorithm{
signatureRSAPSSWithSHA256,
signatureRSAPKCS1WithSHA256,
signatureECDSAWithP256AndSHA256,
signatureRSAPKCS1WithSHA1,
signatureECDSAWithSHA1,
}
// SRTP protection profiles (See RFC 5764, section 4.1.2)
const (
SRTP_AES128_CM_HMAC_SHA1_80 uint16 = 0x0001
SRTP_AES128_CM_HMAC_SHA1_32 = 0x0002
)
// TicketFlags values (see draft-ietf-tls-tls13-14, section 4.4.1)
const (
ticketAllowEarlyData = 1
ticketAllowDHEResumption = 2
ticketAllowPSKResumption = 4
)
// ConnectionState records basic TLS details about the connection.
type ConnectionState struct {
Version uint16 // TLS version used by the connection (e.g. VersionTLS12)
HandshakeComplete bool // TLS handshake is complete
DidResume bool // connection resumes a previous TLS connection
CipherSuite uint16 // cipher suite in use (TLS_RSA_WITH_RC4_128_SHA, ...)
NegotiatedProtocol string // negotiated next protocol (from Config.NextProtos)
NegotiatedProtocolIsMutual bool // negotiated protocol was advertised by server
NegotiatedProtocolFromALPN bool // protocol negotiated with ALPN
ServerName string // server name requested by client, if any (server side only)
PeerCertificates []*x509.Certificate // certificate chain presented by remote peer
VerifiedChains [][]*x509.Certificate // verified chains built from PeerCertificates
ChannelID *ecdsa.PublicKey // the channel ID for this connection
SRTPProtectionProfile uint16 // the negotiated DTLS-SRTP protection profile
TLSUnique []byte // the tls-unique channel binding
SCTList []byte // signed certificate timestamp list
PeerSignatureAlgorithm signatureAlgorithm // algorithm used by the peer in the handshake
CurveID CurveID // the curve used in ECDHE
}
// ClientAuthType declares the policy the server will follow for
// TLS Client Authentication.
type ClientAuthType int
const (
NoClientCert ClientAuthType = iota
RequestClientCert
RequireAnyClientCert
VerifyClientCertIfGiven
RequireAndVerifyClientCert
)
// ClientSessionState contains the state needed by clients to resume TLS
// sessions.
type ClientSessionState struct {
sessionId []uint8 // Session ID supplied by the server. nil if the session has a ticket.
sessionTicket []uint8 // Encrypted ticket used for session resumption with server
vers uint16 // SSL/TLS version negotiated for the session
cipherSuite uint16 // Ciphersuite negotiated for the session
masterSecret []byte // MasterSecret generated by client on a full handshake
handshakeHash []byte // Handshake hash for Channel ID purposes.
serverCertificates []*x509.Certificate // Certificate chain presented by the server
extendedMasterSecret bool // Whether an extended master secret was used to generate the session
sctList []byte
ocspResponse []byte
ticketCreationTime time.Time
ticketExpiration time.Time
ticketFlags uint32
ticketAgeAdd uint32
}
// ClientSessionCache is a cache of ClientSessionState objects that can be used
// by a client to resume a TLS session with a given server. ClientSessionCache
// implementations should expect to be called concurrently from different
// goroutines.
type ClientSessionCache interface {
// Get searches for a ClientSessionState associated with the given key.
// On return, ok is true if one was found.
Get(sessionKey string) (session *ClientSessionState, ok bool)
// Put adds the ClientSessionState to the cache with the given key.
Put(sessionKey string, cs *ClientSessionState)
}
// ServerSessionCache is a cache of sessionState objects that can be used by a
// client to resume a TLS session with a given server. ServerSessionCache
// implementations should expect to be called concurrently from different
// goroutines.
type ServerSessionCache interface {
// Get searches for a sessionState associated with the given session
// ID. On return, ok is true if one was found.
Get(sessionId string) (session *sessionState, ok bool)
// Put adds the sessionState to the cache with the given session ID.
Put(sessionId string, session *sessionState)
}
// A Config structure is used to configure a TLS client or server.
// After one has been passed to a TLS function it must not be
// modified. A Config may be reused; the tls package will also not
// modify it.
type Config struct {
// Rand provides the source of entropy for nonces and RSA blinding.
// If Rand is nil, TLS uses the cryptographic random reader in package
// crypto/rand.
// The Reader must be safe for use by multiple goroutines.
Rand io.Reader
// Time returns the current time as the number of seconds since the epoch.
// If Time is nil, TLS uses time.Now.
Time func() time.Time
// Certificates contains one or more certificate chains
// to present to the other side of the connection.
// Server configurations must include at least one certificate.
Certificates []Certificate
// NameToCertificate maps from a certificate name to an element of
// Certificates. Note that a certificate name can be of the form
// '*.example.com' and so doesn't have to be a domain name as such.
// See Config.BuildNameToCertificate
// The nil value causes the first element of Certificates to be used
// for all connections.
NameToCertificate map[string]*Certificate
// RootCAs defines the set of root certificate authorities
// that clients use when verifying server certificates.
// If RootCAs is nil, TLS uses the host's root CA set.
RootCAs *x509.CertPool
// NextProtos is a list of supported, application level protocols.
NextProtos []string
// ServerName is used to verify the hostname on the returned
// certificates unless InsecureSkipVerify is given. It is also included
// in the client's handshake to support virtual hosting.
ServerName string
// ClientAuth determines the server's policy for
// TLS Client Authentication. The default is NoClientCert.
ClientAuth ClientAuthType
// ClientCAs defines the set of root certificate authorities
// that servers use if required to verify a client certificate
// by the policy in ClientAuth.
ClientCAs *x509.CertPool
// ClientCertificateTypes defines the set of allowed client certificate
// types. The default is CertTypeRSASign and CertTypeECDSASign.
ClientCertificateTypes []byte
// InsecureSkipVerify controls whether a client verifies the
// server's certificate chain and host name.
// If InsecureSkipVerify is true, TLS accepts any certificate
// presented by the server and any host name in that certificate.
// In this mode, TLS is susceptible to man-in-the-middle attacks.
// This should be used only for testing.
InsecureSkipVerify bool
// CipherSuites is a list of supported cipher suites. If CipherSuites
// is nil, TLS uses a list of suites supported by the implementation.
CipherSuites []uint16
// PreferServerCipherSuites controls whether the server selects the
// client's most preferred ciphersuite, or the server's most preferred
// ciphersuite. If true then the server's preference, as expressed in
// the order of elements in CipherSuites, is used.
PreferServerCipherSuites bool
// SessionTicketsDisabled may be set to true to disable session ticket
// (resumption) support.
SessionTicketsDisabled bool
// SessionTicketKey is used by TLS servers to provide session
// resumption. See RFC 5077. If zero, it will be filled with
// random data before the first server handshake.
//
// If multiple servers are terminating connections for the same host
// they should all have the same SessionTicketKey. If the
// SessionTicketKey leaks, previously recorded and future TLS
// connections using that key are compromised.
SessionTicketKey [32]byte
// ClientSessionCache is a cache of ClientSessionState entries
// for TLS session resumption.
ClientSessionCache ClientSessionCache
// ServerSessionCache is a cache of sessionState entries for TLS session
// resumption.
ServerSessionCache ServerSessionCache
// MinVersion contains the minimum SSL/TLS version that is acceptable.
// If zero, then SSLv3 is taken as the minimum.
MinVersion uint16
// MaxVersion contains the maximum SSL/TLS version that is acceptable.
// If zero, then the maximum version supported by this package is used,
// which is currently TLS 1.2.
MaxVersion uint16
// CurvePreferences contains the elliptic curves that will be used in
// an ECDHE handshake, in preference order. If empty, the default will
// be used.
CurvePreferences []CurveID
// DefaultCurves contains the elliptic curves for which public values will
// be sent in the ClientHello's KeyShare extension. If this value is nil,
// all supported curves will have public values sent. This field is ignored
// on servers.
DefaultCurves []CurveID
// ChannelID contains the ECDSA key for the client to use as
// its TLS Channel ID.
ChannelID *ecdsa.PrivateKey
// RequestChannelID controls whether the server requests a TLS
// Channel ID. If negotiated, the client's public key is
// returned in the ConnectionState.
RequestChannelID bool
// PreSharedKey, if not nil, is the pre-shared key to use with
// the PSK cipher suites.
PreSharedKey []byte
// PreSharedKeyIdentity, if not empty, is the identity to use
// with the PSK cipher suites.
PreSharedKeyIdentity string
// SRTPProtectionProfiles, if not nil, is the list of SRTP
// protection profiles to offer in DTLS-SRTP.
SRTPProtectionProfiles []uint16
// SignSignatureAlgorithms, if not nil, overrides the default set of
// supported signature algorithms to sign with.
SignSignatureAlgorithms []signatureAlgorithm
// VerifySignatureAlgorithms, if not nil, overrides the default set of
// supported signature algorithms that are accepted.
VerifySignatureAlgorithms []signatureAlgorithm
// Bugs specifies optional misbehaviour to be used for testing other
// implementations.
Bugs ProtocolBugs
serverInitOnce sync.Once // guards calling (*Config).serverInit
}
type BadValue int
const (
BadValueNone BadValue = iota
BadValueNegative
BadValueZero
BadValueLimit
BadValueLarge
NumBadValues
)
type RSABadValue int
const (
RSABadValueNone RSABadValue = iota
RSABadValueCorrupt
RSABadValueTooLong
RSABadValueTooShort
RSABadValueWrongVersion
NumRSABadValues
)
type ProtocolBugs struct {
// InvalidSignature specifies that the signature in a ServerKeyExchange
// or CertificateVerify message should be invalid.
InvalidSignature bool
// SendCurve, if non-zero, causes the server to send the specified curve
// ID in ServerKeyExchange (TLS 1.2) or ServerHello (TLS 1.3) rather
// than the negotiated one.
SendCurve CurveID
// SendHelloRetryRequestCurve, if non-zero, causes the server to send
// the specified curve in HelloRetryRequest rather than the negotiated
// one.
SendHelloRetryRequestCurve CurveID
// InvalidECDHPoint, if true, causes the ECC points in
// ServerKeyExchange or ClientKeyExchange messages to be invalid.
InvalidECDHPoint bool
// BadECDSAR controls ways in which the 'r' value of an ECDSA signature
// can be invalid.
BadECDSAR BadValue
BadECDSAS BadValue
// MaxPadding causes CBC records to have the maximum possible padding.
MaxPadding bool
// PaddingFirstByteBad causes the first byte of the padding to be
// incorrect.
PaddingFirstByteBad bool
// PaddingFirstByteBadIf255 causes the first byte of padding to be
// incorrect if there's a maximum amount of padding (i.e. 255 bytes).
PaddingFirstByteBadIf255 bool
// FailIfNotFallbackSCSV causes a server handshake to fail if the
// client doesn't send the fallback SCSV value.
FailIfNotFallbackSCSV bool
// DuplicateExtension causes an extra empty extension of bogus type to
// be emitted in either the ClientHello or the ServerHello.
DuplicateExtension bool
// UnauthenticatedECDH causes the server to pretend ECDHE_RSA
// and ECDHE_ECDSA cipher suites are actually ECDH_anon. No
// Certificate message is sent and no signature is added to
// ServerKeyExchange.
UnauthenticatedECDH bool
// SkipHelloVerifyRequest causes a DTLS server to skip the
// HelloVerifyRequest message.
SkipHelloVerifyRequest bool
// SkipCertificateStatus, if true, causes the server to skip the
// CertificateStatus message. This is legal because CertificateStatus is
// optional, even with a status_request in ServerHello.
SkipCertificateStatus bool
// SkipServerKeyExchange causes the server to skip sending
// ServerKeyExchange messages.
SkipServerKeyExchange bool
// SkipNewSessionTicket causes the server to skip sending the
// NewSessionTicket message despite promising to in ServerHello.
SkipNewSessionTicket bool
// SkipClientCertificate causes the client to skip the Certificate
// message.
SkipClientCertificate bool
// SkipChangeCipherSpec causes the implementation to skip
// sending the ChangeCipherSpec message (and adjusting cipher
// state accordingly for the Finished message).
SkipChangeCipherSpec bool
// SkipFinished causes the implementation to skip sending the Finished
// message.
SkipFinished bool
// EarlyChangeCipherSpec causes the client to send an early
// ChangeCipherSpec message before the ClientKeyExchange. A value of
// zero disables this behavior. One and two configure variants for 0.9.8
// and 1.0.1 modes, respectively.
EarlyChangeCipherSpec int
// StrayChangeCipherSpec causes every pre-ChangeCipherSpec handshake
// message in DTLS to be prefaced by stray ChangeCipherSpec record. This
// may be used to test DTLS's handling of reordered ChangeCipherSpec.
StrayChangeCipherSpec bool
// FragmentAcrossChangeCipherSpec causes the implementation to fragment
// the Finished (or NextProto) message around the ChangeCipherSpec
// messages.
FragmentAcrossChangeCipherSpec bool
// SendUnencryptedFinished, if true, causes the Finished message to be
// send unencrypted before ChangeCipherSpec rather than after it.
SendUnencryptedFinished bool
// PartialEncryptedExtensionsWithServerHello, if true, causes the TLS
// 1.3 server to send part of EncryptedExtensions unencrypted
// in the same record as ServerHello.
PartialEncryptedExtensionsWithServerHello bool
// PartialClientFinishedWithClientHello, if true, causes the TLS 1.3
// client to send part of Finished unencrypted in the same record as
// ClientHello.
PartialClientFinishedWithClientHello bool
// SendV2ClientHello causes the client to send a V2ClientHello
// instead of a normal ClientHello.
SendV2ClientHello bool
// SendFallbackSCSV causes the client to include
// TLS_FALLBACK_SCSV in the ClientHello.
SendFallbackSCSV bool
// SendRenegotiationSCSV causes the client to include the renegotiation
// SCSV in the ClientHello.
SendRenegotiationSCSV bool
// MaxHandshakeRecordLength, if non-zero, is the maximum size of a
// handshake record. Handshake messages will be split into multiple
// records at the specified size, except that the client_version will
// never be fragmented. For DTLS, it is the maximum handshake fragment
// size, not record size; DTLS allows multiple handshake fragments in a
// single handshake record. See |PackHandshakeFragments|.
MaxHandshakeRecordLength int
// FragmentClientVersion will allow MaxHandshakeRecordLength to apply to
// the first 6 bytes of the ClientHello.
FragmentClientVersion bool
// FragmentAlert will cause all alerts to be fragmented across
// two records.
FragmentAlert bool
// DoubleAlert will cause all alerts to be sent as two copies packed
// within one record.
DoubleAlert bool
// SendSpuriousAlert, if non-zero, will cause an spurious, unwanted
// alert to be sent.
SendSpuriousAlert alert
// BadRSAClientKeyExchange causes the client to send a corrupted RSA
// ClientKeyExchange which would not pass padding checks.
BadRSAClientKeyExchange RSABadValue
// RenewTicketOnResume causes the server to renew the session ticket and
// send a NewSessionTicket message during an abbreviated handshake.
RenewTicketOnResume bool
// SendClientVersion, if non-zero, causes the client to send a different
// TLS version in the ClientHello than the maximum supported version.
SendClientVersion uint16
// NegotiateVersion, if non-zero, causes the server to negotiate the
// specifed TLS version rather than the version supported by either
// peer.
NegotiateVersion uint16
// NegotiateVersionOnRenego, if non-zero, causes the server to negotiate
// the specified TLS version on renegotiation rather than retaining it.
NegotiateVersionOnRenego uint16
// ExpectFalseStart causes the server to, on full handshakes,
// expect the peer to False Start; the server Finished message
// isn't sent until we receive an application data record
// from the peer.
ExpectFalseStart bool
// AlertBeforeFalseStartTest, if non-zero, causes the server to, on full
// handshakes, send an alert just before reading the application data
// record to test False Start. This can be used in a negative False
// Start test to determine whether the peer processed the alert (and
// closed the connection) before or after sending app data.
AlertBeforeFalseStartTest alert
// ExpectServerName, if not empty, is the hostname the client
// must specify in the server_name extension.
ExpectServerName string
// SwapNPNAndALPN switches the relative order between NPN and ALPN in
// both ClientHello and ServerHello.
SwapNPNAndALPN bool
// ALPNProtocol, if not nil, sets the ALPN protocol that a server will
// return.
ALPNProtocol *string
// AcceptAnySession causes the server to resume sessions regardless of
// the version associated with the session or cipher suite. It also
// causes the server to look in both TLS 1.2 and 1.3 extensions to
// process a ticket.
AcceptAnySession bool
// SendBothTickets, if true, causes the client to send tickets in both
// TLS 1.2 and 1.3 extensions.
SendBothTickets bool
// CorruptTicket causes a client to corrupt a session ticket before
// sending it in a resume handshake.
CorruptTicket bool
// OversizedSessionId causes the session id that is sent with a ticket
// resumption attempt to be too large (33 bytes).
OversizedSessionId bool
// ExpectNoTLS12Session, if true, causes the server to fail the
// connection if either a session ID or TLS 1.2 ticket is offered.
ExpectNoTLS12Session bool
// ExpectNoTLS13PSK, if true, causes the server to fail the connection
// if a TLS 1.3 PSK is offered.
ExpectNoTLS13PSK bool
// RequireExtendedMasterSecret, if true, requires that the peer support
// the extended master secret option.
RequireExtendedMasterSecret bool
// NoExtendedMasterSecret causes the client and server to behave as if
// they didn't support an extended master secret in the initial
// handshake.
NoExtendedMasterSecret bool
// NoExtendedMasterSecretOnRenegotiation causes the client and server to
// behave as if they didn't support an extended master secret in
// renegotiation handshakes.
NoExtendedMasterSecretOnRenegotiation bool
// EmptyRenegotiationInfo causes the renegotiation extension to be
// empty in a renegotiation handshake.
EmptyRenegotiationInfo bool
// BadRenegotiationInfo causes the renegotiation extension value in a
// renegotiation handshake to be incorrect.
BadRenegotiationInfo bool
// NoRenegotiationInfo disables renegotiation info support in all
// handshakes.
NoRenegotiationInfo bool
// NoRenegotiationInfoInInitial disables renegotiation info support in
// the initial handshake.
NoRenegotiationInfoInInitial bool
// NoRenegotiationInfoAfterInitial disables renegotiation info support
// in renegotiation handshakes.
NoRenegotiationInfoAfterInitial bool
// RequireRenegotiationInfo, if true, causes the client to return an
// error if the server doesn't reply with the renegotiation extension.
RequireRenegotiationInfo bool
// SequenceNumberMapping, if non-nil, is the mapping function to apply
// to the sequence number of outgoing packets. For both TLS and DTLS,
// the two most-significant bytes in the resulting sequence number are
// ignored so that the DTLS epoch cannot be changed.
SequenceNumberMapping func(uint64) uint64
// RSAEphemeralKey, if true, causes the server to send a
// ServerKeyExchange message containing an ephemeral key (as in
// RSA_EXPORT) in the plain RSA key exchange.
RSAEphemeralKey bool
// SRTPMasterKeyIdentifer, if not empty, is the SRTP MKI value that the
// client offers when negotiating SRTP. MKI support is still missing so
// the peer must still send none.
SRTPMasterKeyIdentifer string
// SendSRTPProtectionProfile, if non-zero, is the SRTP profile that the
// server sends in the ServerHello instead of the negotiated one.
SendSRTPProtectionProfile uint16
// NoSignatureAlgorithms, if true, causes the client to omit the
// signature and hashes extension.
//
// For a server, it will cause an empty list to be sent in the
// CertificateRequest message. None the less, the configured set will
// still be enforced.
NoSignatureAlgorithms bool
// NoSupportedCurves, if true, causes the client to omit the
// supported_curves extension.
NoSupportedCurves bool
// RequireSameRenegoClientVersion, if true, causes the server
// to require that all ClientHellos match in offered version
// across a renego.
RequireSameRenegoClientVersion bool
// ExpectInitialRecordVersion, if non-zero, is the expected
// version of the records before the version is determined.
ExpectInitialRecordVersion uint16
// MaxPacketLength, if non-zero, is the maximum acceptable size for a
// packet.
MaxPacketLength int
// SendCipherSuite, if non-zero, is the cipher suite value that the
// server will send in the ServerHello. This does not affect the cipher
// the server believes it has actually negotiated.
SendCipherSuite uint16
// AppDataBeforeHandshake, if not nil, causes application data to be
// sent immediately before the first handshake message.
AppDataBeforeHandshake []byte
// AppDataAfterChangeCipherSpec, if not nil, causes application data to
// be sent immediately after ChangeCipherSpec.
AppDataAfterChangeCipherSpec []byte
// AlertAfterChangeCipherSpec, if non-zero, causes an alert to be sent
// immediately after ChangeCipherSpec.
AlertAfterChangeCipherSpec alert
// TimeoutSchedule is the schedule of packet drops and simulated
// timeouts for before each handshake leg from the peer.
TimeoutSchedule []time.Duration
// PacketAdaptor is the packetAdaptor to use to simulate timeouts.
PacketAdaptor *packetAdaptor
// ReorderHandshakeFragments, if true, causes handshake fragments in
// DTLS to overlap and be sent in the wrong order. It also causes
// pre-CCS flights to be sent twice. (Post-CCS flights consist of
// Finished and will trigger a spurious retransmit.)
ReorderHandshakeFragments bool
// ReverseHandshakeFragments, if true, causes handshake fragments in
// DTLS to be reversed within a flight.
ReverseHandshakeFragments bool
// MixCompleteMessageWithFragments, if true, causes handshake
// messages in DTLS to redundantly both fragment the message
// and include a copy of the full one.
MixCompleteMessageWithFragments bool
// SendInvalidRecordType, if true, causes a record with an invalid
// content type to be sent immediately following the handshake.
SendInvalidRecordType bool
// SendWrongMessageType, if non-zero, causes messages of the specified
// type to be sent with the wrong value.
SendWrongMessageType byte
// SendTrailingMessageData, if non-zero, causes messages of the
// specified type to be sent with trailing data.
SendTrailingMessageData byte
// FragmentMessageTypeMismatch, if true, causes all non-initial
// handshake fragments in DTLS to have the wrong message type.
FragmentMessageTypeMismatch bool
// FragmentMessageLengthMismatch, if true, causes all non-initial
// handshake fragments in DTLS to have the wrong message length.
FragmentMessageLengthMismatch bool
// SplitFragments, if non-zero, causes the handshake fragments in DTLS
// to be split across two records. The value of |SplitFragments| is the
// number of bytes in the first fragment.
SplitFragments int
// SendEmptyFragments, if true, causes handshakes to include empty
// fragments in DTLS.
SendEmptyFragments bool
// SendSplitAlert, if true, causes an alert to be sent with the header
// and record body split across multiple packets. The peer should
// discard these packets rather than process it.
SendSplitAlert bool
// FailIfResumeOnRenego, if true, causes renegotiations to fail if the
// client offers a resumption or the server accepts one.
FailIfResumeOnRenego bool
// IgnorePeerCipherPreferences, if true, causes the peer's cipher
// preferences to be ignored.
IgnorePeerCipherPreferences bool
// IgnorePeerSignatureAlgorithmPreferences, if true, causes the peer's
// signature algorithm preferences to be ignored.
IgnorePeerSignatureAlgorithmPreferences bool
// IgnorePeerCurvePreferences, if true, causes the peer's curve
// preferences to be ignored.
IgnorePeerCurvePreferences bool
// BadFinished, if true, causes the Finished hash to be broken.
BadFinished bool
// DHGroupPrime, if not nil, is used to define the (finite field)
// Diffie-Hellman group. The generator used is always two.
DHGroupPrime *big.Int
// PackHandshakeFragments, if true, causes handshake fragments in DTLS
// to be packed into individual handshake records, up to the specified
// record size.
PackHandshakeFragments int
// PackHandshakeRecords, if true, causes handshake records in DTLS to be
// packed into individual packets, up to the specified packet size.
PackHandshakeRecords int
// PackHandshakeFlight, if true, causes each handshake flight in TLS to
// be packed into records, up to the largest size record available.
PackHandshakeFlight bool
// EnableAllCiphers, if true, causes all configured ciphers to be
// enabled.
EnableAllCiphers bool
// EmptyCertificateList, if true, causes the server to send an empty
// certificate list in the Certificate message.
EmptyCertificateList bool
// ExpectNewTicket, if true, causes the client to abort if it does not
// receive a new ticket.
ExpectNewTicket bool
// RequireClientHelloSize, if not zero, is the required length in bytes
// of the ClientHello /record/. This is checked by the server.
RequireClientHelloSize int
// CustomExtension, if not empty, contains the contents of an extension
// that will be added to client/server hellos.
CustomExtension string
// ExpectedCustomExtension, if not nil, contains the expected contents
// of a custom extension.
ExpectedCustomExtension *string
// NoCloseNotify, if true, causes the close_notify alert to be skipped
// on connection shutdown.
NoCloseNotify bool
// SendAlertOnShutdown, if non-zero, is the alert to send instead of
// close_notify on shutdown.
SendAlertOnShutdown alert
// ExpectCloseNotify, if true, requires a close_notify from the peer on
// shutdown. Records from the peer received after close_notify is sent
// are not discard.
ExpectCloseNotify bool
// SendLargeRecords, if true, allows outgoing records to be sent
// arbitrarily large.
SendLargeRecords bool
// NegotiateALPNAndNPN, if true, causes the server to negotiate both
// ALPN and NPN in the same connetion.
NegotiateALPNAndNPN bool
// SendALPN, if non-empty, causes the server to send the specified
// string in the ALPN extension regardless of the content or presence of
// the client offer.
SendALPN string
// SendEmptySessionTicket, if true, causes the server to send an empty
// session ticket.
SendEmptySessionTicket bool
// FailIfSessionOffered, if true, causes the server to fail any
// connections where the client offers a non-empty session ID or session
// ticket.
FailIfSessionOffered bool
// SendHelloRequestBeforeEveryAppDataRecord, if true, causes a
// HelloRequest handshake message to be sent before each application
// data record. This only makes sense for a server.
SendHelloRequestBeforeEveryAppDataRecord bool
// SendHelloRequestBeforeEveryHandshakeMessage, if true, causes a
// HelloRequest handshake message to be sent before each handshake
// message. This only makes sense for a server.
SendHelloRequestBeforeEveryHandshakeMessage bool
// SendKeyUpdateBeforeEveryAppDataRecord, if true, causes a KeyUpdate
// handshake message to be sent before each application data record.
SendKeyUpdateBeforeEveryAppDataRecord bool
// RequireDHPublicValueLen causes a fatal error if the length (in
// bytes) of the server's Diffie-Hellman public value is not equal to
// this.
RequireDHPublicValueLen int
// BadChangeCipherSpec, if not nil, is the body to be sent in
// ChangeCipherSpec records instead of {1}.
BadChangeCipherSpec []byte
// BadHelloRequest, if not nil, is what to send instead of a
// HelloRequest.
BadHelloRequest []byte
// RequireSessionTickets, if true, causes the client to require new
// sessions use session tickets instead of session IDs.
RequireSessionTickets bool
// NullAllCiphers, if true, causes every cipher to behave like the null
// cipher.
NullAllCiphers bool
// SendSCTListOnResume, if not nil, causes the server to send the
// supplied SCT list in resumption handshakes.
SendSCTListOnResume []byte
// CECPQ1BadX25519Part corrupts the X25519 part of a CECPQ1 key exchange, as
// a trivial proof that it is actually used.
CECPQ1BadX25519Part bool
// CECPQ1BadNewhopePart corrupts the Newhope part of a CECPQ1 key exchange,
// as a trivial proof that it is actually used.
CECPQ1BadNewhopePart bool
// RecordPadding is the number of bytes of padding to add to each
// encrypted record in TLS 1.3.
RecordPadding int
// OmitRecordContents, if true, causes encrypted records in TLS 1.3 to
// be missing their body and content type. Padding, if configured, is
// still added.
OmitRecordContents bool
// OuterRecordType, if non-zero, is the outer record type to use instead
// of application data.
OuterRecordType recordType
// SendSignatureAlgorithm, if non-zero, causes all signatures to be sent
// with the given signature algorithm rather than the one negotiated.
SendSignatureAlgorithm signatureAlgorithm
// SkipECDSACurveCheck, if true, causes all ECDSA curve checks to be
// skipped.
SkipECDSACurveCheck bool
// IgnoreSignatureVersionChecks, if true, causes all signature
// algorithms to be enabled at all TLS versions.
IgnoreSignatureVersionChecks bool
// NegotiateRenegotiationInfoAtAllVersions, if true, causes
// Renegotiation Info to be negotiated at all versions.
NegotiateRenegotiationInfoAtAllVersions bool
// NegotiateChannelIDAtAllVersions, if true, causes Channel ID to be
// negotiated at all versions.
NegotiateChannelIDAtAllVersions bool
// NegotiateNPNAtAllVersions, if true, causes NPN to be negotiated at
// all versions.
NegotiateNPNAtAllVersions bool
// NegotiateEMSAtAllVersions, if true, causes EMS to be negotiated at
// all versions.
NegotiateEMSAtAllVersions bool
// AdvertiseTicketExtension, if true, causes the ticket extension to be
// advertised in server extensions
AdvertiseTicketExtension bool
// MissingKeyShare, if true, causes the TLS 1.3 implementation to skip
// sending a key_share extension and use the zero ECDHE secret
// instead.
MissingKeyShare bool
// SecondClientHelloMissingKeyShare, if true, causes the second TLS 1.3
// ClientHello to skip sending a key_share extension and use the zero
// ECDHE secret instead.
SecondClientHelloMissingKeyShare bool
// MisinterpretHelloRetryRequestCurve, if non-zero, causes the TLS 1.3
// client to pretend the server requested a HelloRetryRequest with the
// given curve rather than the actual one.
MisinterpretHelloRetryRequestCurve CurveID
// DuplicateKeyShares, if true, causes the TLS 1.3 client to send two
// copies of each KeyShareEntry.
DuplicateKeyShares bool
// EmptyEncryptedExtensions, if true, causes the TLS 1.3 server to
// emit an empty EncryptedExtensions block.
EmptyEncryptedExtensions bool
// EncryptedExtensionsWithKeyShare, if true, causes the TLS 1.3 server to
// include the KeyShare extension in the EncryptedExtensions block.
EncryptedExtensionsWithKeyShare bool
// UnnecessaryHelloRetryRequest, if true, causes the TLS 1.3 server to
// send a HelloRetryRequest regardless of whether it needs to.
UnnecessaryHelloRetryRequest bool
// SecondHelloRetryRequest, if true, causes the TLS 1.3 server to send
// two HelloRetryRequests instead of one.
SecondHelloRetryRequest bool
// SendServerHelloVersion, if non-zero, causes the server to send the
// specified version in ServerHello rather than the true version.
SendServerHelloVersion uint16
// SkipHelloRetryRequest, if true, causes the TLS 1.3 server to not send
// HelloRetryRequest.
SkipHelloRetryRequest bool
// PackHelloRequestWithFinished, if true, causes the TLS server to send
// HelloRequest in the same record as Finished.
PackHelloRequestWithFinished bool
// ExpectMissingKeyShare, if true, causes the TLS server to fail the
// connection if the selected curve appears in the client's initial
// ClientHello. That is, it requires that a HelloRetryRequest be sent.
ExpectMissingKeyShare bool
// SendExtraFinished, if true, causes an extra Finished message to be
// sent.
SendExtraFinished bool
// SendRequestContext, if not empty, is the request context to send in
// a TLS 1.3 CertificateRequest.
SendRequestContext []byte
// SendSNIWarningAlert, if true, causes the server to send an
// unrecognized_name alert before the ServerHello.
SendSNIWarningAlert bool
// SendCompressionMethods, if not nil, is the compression method list to
// send in the ClientHello.
SendCompressionMethods []byte
// AlwaysSendPreSharedKeyIdentityHint, if true, causes the server to
// always send a ServerKeyExchange for PSK ciphers, even if the identity
// hint is empty.
AlwaysSendPreSharedKeyIdentityHint bool
// TrailingKeyShareData, if true, causes the client key share list to
// include a trailing byte.
TrailingKeyShareData bool
}
func (c *Config) serverInit() {
if c.SessionTicketsDisabled {
return
}
// If the key has already been set then we have nothing to do.
for _, b := range c.SessionTicketKey {
if b != 0 {
return
}
}
if _, err := io.ReadFull(c.rand(), c.SessionTicketKey[:]); err != nil {
c.SessionTicketsDisabled = true
}
}
func (c *Config) rand() io.Reader {
r := c.Rand
if r == nil {
return rand.Reader
}
return r
}
func (c *Config) time() time.Time {
t := c.Time
if t == nil {
t = time.Now
}
return t()
}
func (c *Config) cipherSuites() []uint16 {
s := c.CipherSuites
if s == nil {
s = defaultCipherSuites()
}
return s
}
func (c *Config) minVersion(isDTLS bool) uint16 {
ret := uint16(minVersion)
if c != nil && c.MinVersion != 0 {
ret = c.MinVersion
}
if isDTLS {
// The lowest version of DTLS is 1.0. There is no DSSL 3.0.
if ret < VersionTLS10 {
return VersionTLS10
}
// There is no such thing as DTLS 1.1.
if ret == VersionTLS11 {
return VersionTLS12
}
}
return ret
}
func (c *Config) maxVersion(isDTLS bool) uint16 {
ret := uint16(maxVersion)
if c != nil && c.MaxVersion != 0 {
ret = c.MaxVersion
}
if isDTLS {
// We only implement up to DTLS 1.2.
if ret > VersionTLS12 {
return VersionTLS12
}
// There is no such thing as DTLS 1.1.
if ret == VersionTLS11 {
return VersionTLS10
}
}
return ret
}
var defaultCurvePreferences = []CurveID{CurveX25519, CurveP256, CurveP384, CurveP521}
func (c *Config) curvePreferences() []CurveID {
if c == nil || len(c.CurvePreferences) == 0 {
return defaultCurvePreferences
}
return c.CurvePreferences
}
func (c *Config) defaultCurves() map[CurveID]bool {
defaultCurves := make(map[CurveID]bool)
curves := c.DefaultCurves
if c == nil || c.DefaultCurves == nil {
curves = c.curvePreferences()
}
for _, curveID := range curves {
defaultCurves[curveID] = true
}
return defaultCurves
}
// mutualVersion returns the protocol version to use given the advertised
// version of the peer.
func (c *Config) mutualVersion(vers uint16, isDTLS bool) (uint16, bool) {
// There is no such thing as DTLS 1.1.
if isDTLS && vers == VersionTLS11 {
vers = VersionTLS10
}
minVersion := c.minVersion(isDTLS)
maxVersion := c.maxVersion(isDTLS)
if vers < minVersion {
return 0, false
}
if vers > maxVersion {
vers = maxVersion
}
return vers, true
}
// getCertificateForName returns the best certificate for the given name,
// defaulting to the first element of c.Certificates if there are no good
// options.
func (c *Config) getCertificateForName(name string) *Certificate {
if len(c.Certificates) == 1 || c.NameToCertificate == nil {
// There's only one choice, so no point doing any work.
return &c.Certificates[0]
}
name = strings.ToLower(name)
for len(name) > 0 && name[len(name)-1] == '.' {
name = name[:len(name)-1]
}
if cert, ok := c.NameToCertificate[name]; ok {
return cert
}
// try replacing labels in the name with wildcards until we get a
// match.
labels := strings.Split(name, ".")
for i := range labels {
labels[i] = "*"
candidate := strings.Join(labels, ".")
if cert, ok := c.NameToCertificate[candidate]; ok {
return cert
}
}
// If nothing matches, return the first certificate.
return &c.Certificates[0]
}
func (c *Config) signSignatureAlgorithms() []signatureAlgorithm {
if c != nil && c.SignSignatureAlgorithms != nil {
return c.SignSignatureAlgorithms
}
return supportedSignatureAlgorithms
}
func (c *Config) verifySignatureAlgorithms() []signatureAlgorithm {
if c != nil && c.VerifySignatureAlgorithms != nil {
return c.VerifySignatureAlgorithms
}
return supportedSignatureAlgorithms
}
// BuildNameToCertificate parses c.Certificates and builds c.NameToCertificate
// from the CommonName and SubjectAlternateName fields of each of the leaf
// certificates.
func (c *Config) BuildNameToCertificate() {
c.NameToCertificate = make(map[string]*Certificate)
for i := range c.Certificates {
cert := &c.Certificates[i]
x509Cert, err := x509.ParseCertificate(cert.Certificate[0])
if err != nil {
continue
}
if len(x509Cert.Subject.CommonName) > 0 {
c.NameToCertificate[x509Cert.Subject.CommonName] = cert
}
for _, san := range x509Cert.DNSNames {
c.NameToCertificate[san] = cert
}
}
}
// A Certificate is a chain of one or more certificates, leaf first.
type Certificate struct {
Certificate [][]byte
PrivateKey crypto.PrivateKey // supported types: *rsa.PrivateKey, *ecdsa.PrivateKey
// OCSPStaple contains an optional OCSP response which will be served
// to clients that request it.
OCSPStaple []byte
// SignedCertificateTimestampList contains an optional encoded
// SignedCertificateTimestampList structure which will be
// served to clients that request it.
SignedCertificateTimestampList []byte
// Leaf is the parsed form of the leaf certificate, which may be
// initialized using x509.ParseCertificate to reduce per-handshake
// processing for TLS clients doing client authentication. If nil, the
// leaf certificate will be parsed as needed.
Leaf *x509.Certificate
}
// A TLS record.
type record struct {
contentType recordType
major, minor uint8
payload []byte
}
type handshakeMessage interface {
marshal() []byte
unmarshal([]byte) bool
}
// lruSessionCache is a client or server session cache implementation
// that uses an LRU caching strategy.
type lruSessionCache struct {
sync.Mutex
m map[string]*list.Element
q *list.List
capacity int
}
type lruSessionCacheEntry struct {
sessionKey string
state interface{}
}
// Put adds the provided (sessionKey, cs) pair to the cache.
func (c *lruSessionCache) Put(sessionKey string, cs interface{}) {
c.Lock()
defer c.Unlock()
if elem, ok := c.m[sessionKey]; ok {
entry := elem.Value.(*lruSessionCacheEntry)
entry.state = cs
c.q.MoveToFront(elem)
return
}
if c.q.Len() < c.capacity {
entry := &lruSessionCacheEntry{sessionKey, cs}
c.m[sessionKey] = c.q.PushFront(entry)
return
}
elem := c.q.Back()
entry := elem.Value.(*lruSessionCacheEntry)
delete(c.m, entry.sessionKey)
entry.sessionKey = sessionKey
entry.state = cs
c.q.MoveToFront(elem)
c.m[sessionKey] = elem
}
// Get returns the value associated with a given key. It returns (nil,
// false) if no value is found.
func (c *lruSessionCache) Get(sessionKey string) (interface{}, bool) {
c.Lock()
defer c.Unlock()
if elem, ok := c.m[sessionKey]; ok {
c.q.MoveToFront(elem)
return elem.Value.(*lruSessionCacheEntry).state, true
}
return nil, false
}
// lruClientSessionCache is a ClientSessionCache implementation that
// uses an LRU caching strategy.
type lruClientSessionCache struct {
lruSessionCache
}
func (c *lruClientSessionCache) Put(sessionKey string, cs *ClientSessionState) {
c.lruSessionCache.Put(sessionKey, cs)
}
func (c *lruClientSessionCache) Get(sessionKey string) (*ClientSessionState, bool) {
cs, ok := c.lruSessionCache.Get(sessionKey)
if !ok {
return nil, false
}
return cs.(*ClientSessionState), true
}
// lruServerSessionCache is a ServerSessionCache implementation that
// uses an LRU caching strategy.
type lruServerSessionCache struct {
lruSessionCache
}
func (c *lruServerSessionCache) Put(sessionId string, session *sessionState) {
c.lruSessionCache.Put(sessionId, session)
}
func (c *lruServerSessionCache) Get(sessionId string) (*sessionState, bool) {
cs, ok := c.lruSessionCache.Get(sessionId)
if !ok {
return nil, false
}
return cs.(*sessionState), true
}
// NewLRUClientSessionCache returns a ClientSessionCache with the given
// capacity that uses an LRU strategy. If capacity is < 1, a default capacity
// is used instead.
func NewLRUClientSessionCache(capacity int) ClientSessionCache {
const defaultSessionCacheCapacity = 64
if capacity < 1 {
capacity = defaultSessionCacheCapacity
}
return &lruClientSessionCache{
lruSessionCache{
m: make(map[string]*list.Element),
q: list.New(),
capacity: capacity,
},
}
}
// NewLRUServerSessionCache returns a ServerSessionCache with the given
// capacity that uses an LRU strategy. If capacity is < 1, a default capacity
// is used instead.
func NewLRUServerSessionCache(capacity int) ServerSessionCache {
const defaultSessionCacheCapacity = 64
if capacity < 1 {
capacity = defaultSessionCacheCapacity
}
return &lruServerSessionCache{
lruSessionCache{
m: make(map[string]*list.Element),
q: list.New(),
capacity: capacity,
},
}
}
// TODO(jsing): Make these available to both crypto/x509 and crypto/tls.
type dsaSignature struct {
R, S *big.Int
}
type ecdsaSignature dsaSignature
var emptyConfig Config
func defaultConfig() *Config {
return &emptyConfig
}
var (
once sync.Once
varDefaultCipherSuites []uint16
)
func defaultCipherSuites() []uint16 {
once.Do(initDefaultCipherSuites)
return varDefaultCipherSuites
}
func initDefaultCipherSuites() {
for _, suite := range cipherSuites {
if suite.flags&suitePSK == 0 {
varDefaultCipherSuites = append(varDefaultCipherSuites, suite.id)
}
}
}
func unexpectedMessageError(wanted, got interface{}) error {
return fmt.Errorf("tls: received unexpected handshake message of type %T when waiting for %T", got, wanted)
}
func isSupportedSignatureAlgorithm(sigAlg signatureAlgorithm, sigAlgs []signatureAlgorithm) bool {
for _, s := range sigAlgs {
if s == sigAlg {
return true
}
}
return false
}
var (
// See draft-ietf-tls-tls13-13, section 6.3.1.2.
downgradeTLS13 = []byte{0x44, 0x4f, 0x57, 0x4e, 0x47, 0x52, 0x44, 0x01}
downgradeTLS12 = []byte{0x44, 0x4f, 0x57, 0x4e, 0x47, 0x52, 0x44, 0x00}
)