| // 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 tls |
| |
| import ( |
| "container/list" |
| "crypto" |
| "crypto/internal/cipherhw" |
| "crypto/rand" |
| "crypto/sha512" |
| "crypto/x509" |
| "errors" |
| "fmt" |
| "io" |
| "math/big" |
| "net" |
| "strings" |
| "sync" |
| "time" |
| ) |
| |
| const ( |
| VersionSSL30 = 0x0300 |
| VersionTLS10 = 0x0301 |
| VersionTLS11 = 0x0302 |
| VersionTLS12 = 0x0303 |
| ) |
| |
| const ( |
| maxPlaintext = 16384 // maximum plaintext payload length |
| maxCiphertext = 16384 + 2048 // maximum ciphertext payload length |
| recordHeaderLen = 5 // record header length |
| maxHandshake = 65536 // maximum handshake we support (protocol max is 16 MB) |
| |
| minVersion = VersionTLS10 |
| maxVersion = VersionTLS12 |
| ) |
| |
| // 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 |
| typeNewSessionTicket uint8 = 4 |
| typeCertificate uint8 = 11 |
| typeServerKeyExchange uint8 = 12 |
| typeCertificateRequest uint8 = 13 |
| typeServerHelloDone uint8 = 14 |
| typeCertificateVerify uint8 = 15 |
| typeClientKeyExchange uint8 = 16 |
| typeFinished uint8 = 20 |
| typeCertificateStatus uint8 = 22 |
| typeNextProtocol uint8 = 67 // 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 |
| extensionALPN uint16 = 16 |
| extensionSCT uint16 = 18 // https://tools.ietf.org/html/rfc6962#section-6 |
| extensionSessionTicket uint16 = 35 |
| extensionNextProtoNeg uint16 = 13172 // not IANA assigned |
| extensionRenegotiationInfo uint16 = 0xff01 |
| ) |
| |
| // 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 ( |
| CurveP256 CurveID = 23 |
| CurveP384 CurveID = 24 |
| CurveP521 CurveID = 25 |
| X25519 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 RFC 4492 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 |
| ) |
| |
| // Hash functions for TLS 1.2 (See RFC 5246, section A.4.1) |
| const ( |
| hashSHA1 uint8 = 2 |
| hashSHA256 uint8 = 4 |
| hashSHA384 uint8 = 5 |
| ) |
| |
| // Signature algorithms for TLS 1.2 (See RFC 5246, section A.4.1) |
| const ( |
| signatureRSA uint8 = 1 |
| signatureECDSA uint8 = 3 |
| ) |
| |
| // signatureAndHash mirrors the TLS 1.2, SignatureAndHashAlgorithm struct. See |
| // RFC 5246, section A.4.1. |
| type signatureAndHash struct { |
| hash, signature uint8 |
| } |
| |
| // defaultSupportedSignatureAlgorithms contains the signature and hash algorithms that |
| // the code advertises as supported in a TLS 1.2 ClientHello and in a TLS 1.2 |
| // CertificateRequest. |
| var defaultSupportedSignatureAlgorithms = []signatureAndHash{ |
| {hashSHA256, signatureRSA}, |
| {hashSHA256, signatureECDSA}, |
| {hashSHA384, signatureRSA}, |
| {hashSHA384, signatureECDSA}, |
| {hashSHA1, signatureRSA}, |
| {hashSHA1, signatureECDSA}, |
| } |
| |
| // 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 (not guaranteed to be from Config.NextProtos) |
| NegotiatedProtocolIsMutual bool // negotiated protocol was advertised by server (client side only) |
| 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 |
| SignedCertificateTimestamps [][]byte // SCTs from the server, if any |
| OCSPResponse []byte // stapled OCSP response from server, if any |
| |
| // TLSUnique contains the "tls-unique" channel binding value (see RFC |
| // 5929, section 3). For resumed sessions this value will be nil |
| // because resumption does not include enough context (see |
| // https://mitls.org/pages/attacks/3SHAKE#channelbindings). This will |
| // change in future versions of Go once the TLS master-secret fix has |
| // been standardized and implemented. |
| TLSUnique []byte |
| } |
| |
| // 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 { |
| 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 |
| serverCertificates []*x509.Certificate // Certificate chain presented by the server |
| verifiedChains [][]*x509.Certificate // Certificate chains we built for verification |
| } |
| |
| // 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. Only ticket-based resumption is supported, not SessionID-based |
| // resumption. |
| 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) |
| } |
| |
| // SignatureScheme identifies a signature algorithm supported by TLS. See |
| // https://tools.ietf.org/html/draft-ietf-tls-tls13-18#section-4.2.3. |
| type SignatureScheme uint16 |
| |
| const ( |
| PKCS1WithSHA1 SignatureScheme = 0x0201 |
| PKCS1WithSHA256 SignatureScheme = 0x0401 |
| PKCS1WithSHA384 SignatureScheme = 0x0501 |
| PKCS1WithSHA512 SignatureScheme = 0x0601 |
| |
| PSSWithSHA256 SignatureScheme = 0x0804 |
| PSSWithSHA384 SignatureScheme = 0x0805 |
| PSSWithSHA512 SignatureScheme = 0x0806 |
| |
| ECDSAWithP256AndSHA256 SignatureScheme = 0x0403 |
| ECDSAWithP384AndSHA384 SignatureScheme = 0x0503 |
| ECDSAWithP521AndSHA512 SignatureScheme = 0x0603 |
| ) |
| |
| // ClientHelloInfo contains information from a ClientHello message in order to |
| // guide certificate selection in the GetCertificate callback. |
| type ClientHelloInfo struct { |
| // CipherSuites lists the CipherSuites supported by the client (e.g. |
| // TLS_RSA_WITH_RC4_128_SHA). |
| CipherSuites []uint16 |
| |
| // ServerName indicates the name of the server requested by the client |
| // in order to support virtual hosting. ServerName is only set if the |
| // client is using SNI (see |
| // http://tools.ietf.org/html/rfc4366#section-3.1). |
| ServerName string |
| |
| // SupportedCurves lists the elliptic curves supported by the client. |
| // SupportedCurves is set only if the Supported Elliptic Curves |
| // Extension is being used (see |
| // http://tools.ietf.org/html/rfc4492#section-5.1.1). |
| SupportedCurves []CurveID |
| |
| // SupportedPoints lists the point formats supported by the client. |
| // SupportedPoints is set only if the Supported Point Formats Extension |
| // is being used (see |
| // http://tools.ietf.org/html/rfc4492#section-5.1.2). |
| SupportedPoints []uint8 |
| |
| // SignatureSchemes lists the signature and hash schemes that the client |
| // is willing to verify. SignatureSchemes is set only if the Signature |
| // Algorithms Extension is being used (see |
| // https://tools.ietf.org/html/rfc5246#section-7.4.1.4.1). |
| SignatureSchemes []SignatureScheme |
| |
| // SupportedProtos lists the application protocols supported by the client. |
| // SupportedProtos is set only if the Application-Layer Protocol |
| // Negotiation Extension is being used (see |
| // https://tools.ietf.org/html/rfc7301#section-3.1). |
| // |
| // Servers can select a protocol by setting Config.NextProtos in a |
| // GetConfigForClient return value. |
| SupportedProtos []string |
| |
| // SupportedVersions lists the TLS versions supported by the client. |
| // For TLS versions less than 1.3, this is extrapolated from the max |
| // version advertised by the client, so values other than the greatest |
| // might be rejected if used. |
| SupportedVersions []uint16 |
| |
| // Conn is the underlying net.Conn for the connection. Do not read |
| // from, or write to, this connection; that will cause the TLS |
| // connection to fail. |
| Conn net.Conn |
| } |
| |
| // CertificateRequestInfo contains information from a server's |
| // CertificateRequest message, which is used to demand a certificate and proof |
| // of control from a client. |
| type CertificateRequestInfo struct { |
| // AcceptableCAs contains zero or more, DER-encoded, X.501 |
| // Distinguished Names. These are the names of root or intermediate CAs |
| // that the server wishes the returned certificate to be signed by. An |
| // empty slice indicates that the server has no preference. |
| AcceptableCAs [][]byte |
| |
| // SignatureSchemes lists the signature schemes that the server is |
| // willing to verify. |
| SignatureSchemes []SignatureScheme |
| } |
| |
| // RenegotiationSupport enumerates the different levels of support for TLS |
| // renegotiation. TLS renegotiation is the act of performing subsequent |
| // handshakes on a connection after the first. This significantly complicates |
| // the state machine and has been the source of numerous, subtle security |
| // issues. Initiating a renegotiation is not supported, but support for |
| // accepting renegotiation requests may be enabled. |
| // |
| // Even when enabled, the server may not change its identity between handshakes |
| // (i.e. the leaf certificate must be the same). Additionally, concurrent |
| // handshake and application data flow is not permitted so renegotiation can |
| // only be used with protocols that synchronise with the renegotiation, such as |
| // HTTPS. |
| type RenegotiationSupport int |
| |
| const ( |
| // RenegotiateNever disables renegotiation. |
| RenegotiateNever RenegotiationSupport = iota |
| |
| // RenegotiateOnceAsClient allows a remote server to request |
| // renegotiation once per connection. |
| RenegotiateOnceAsClient |
| |
| // RenegotiateFreelyAsClient allows a remote server to repeatedly |
| // request renegotiation. |
| RenegotiateFreelyAsClient |
| ) |
| |
| // 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 or else set GetCertificate. Clients doing |
| // client-authentication may set either Certificates or |
| // GetClientCertificate. |
| 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 |
| |
| // GetCertificate returns a Certificate based on the given |
| // ClientHelloInfo. It will only be called if the client supplies SNI |
| // information or if Certificates is empty. |
| // |
| // If GetCertificate is nil or returns nil, then the certificate is |
| // retrieved from NameToCertificate. If NameToCertificate is nil, the |
| // first element of Certificates will be used. |
| GetCertificate func(*ClientHelloInfo) (*Certificate, error) |
| |
| // GetClientCertificate, if not nil, is called when a server requests a |
| // certificate from a client. If set, the contents of Certificates will |
| // be ignored. |
| // |
| // If GetClientCertificate returns an error, the handshake will be |
| // aborted and that error will be returned. Otherwise |
| // GetClientCertificate must return a non-nil Certificate. If |
| // Certificate.Certificate is empty then no certificate will be sent to |
| // the server. If this is unacceptable to the server then it may abort |
| // the handshake. |
| // |
| // GetClientCertificate may be called multiple times for the same |
| // connection if renegotiation occurs or if TLS 1.3 is in use. |
| GetClientCertificate func(*CertificateRequestInfo) (*Certificate, error) |
| |
| // GetConfigForClient, if not nil, is called after a ClientHello is |
| // received from a client. It may return a non-nil Config in order to |
| // change the Config that will be used to handle this connection. If |
| // the returned Config is nil, the original Config will be used. The |
| // Config returned by this callback may not be subsequently modified. |
| // |
| // If GetConfigForClient is nil, the Config passed to Server() will be |
| // used for all connections. |
| // |
| // Uniquely for the fields in the returned Config, session ticket keys |
| // will be duplicated from the original Config if not set. |
| // Specifically, if SetSessionTicketKeys was called on the original |
| // config but not on the returned config then the ticket keys from the |
| // original config will be copied into the new config before use. |
| // Otherwise, if SessionTicketKey was set in the original config but |
| // not in the returned config then it will be copied into the returned |
| // config before use. If neither of those cases applies then the key |
| // material from the returned config will be used for session tickets. |
| GetConfigForClient func(*ClientHelloInfo) (*Config, error) |
| |
| // VerifyPeerCertificate, if not nil, is called after normal |
| // certificate verification by either a TLS client or server. It |
| // receives the raw ASN.1 certificates provided by the peer and also |
| // any verified chains that normal processing found. If it returns a |
| // non-nil error, the handshake is aborted and that error results. |
| // |
| // If normal verification fails then the handshake will abort before |
| // considering this callback. If normal verification is disabled by |
| // setting InsecureSkipVerify then this callback will be considered but |
| // the verifiedChains argument will always be nil. |
| VerifyPeerCertificate func(rawCerts [][]byte, verifiedChains [][]*x509.Certificate) error |
| |
| // 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 unless it is |
| // an IP address. |
| 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 |
| |
| // 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 |
| |
| // SessionCache is a cache of ClientSessionState entries for TLS session |
| // resumption. |
| ClientSessionCache ClientSessionCache |
| |
| // MinVersion contains the minimum SSL/TLS version that is acceptable. |
| // If zero, then TLS 1.0 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 |
| |
| // DynamicRecordSizingDisabled disables adaptive sizing of TLS records. |
| // When true, the largest possible TLS record size is always used. When |
| // false, the size of TLS records may be adjusted in an attempt to |
| // improve latency. |
| DynamicRecordSizingDisabled bool |
| |
| // Renegotiation controls what types of renegotiation are supported. |
| // The default, none, is correct for the vast majority of applications. |
| Renegotiation RenegotiationSupport |
| |
| // KeyLogWriter optionally specifies a destination for TLS master secrets |
| // in NSS key log format that can be used to allow external programs |
| // such as Wireshark to decrypt TLS connections. |
| // See https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/Key_Log_Format. |
| // Use of KeyLogWriter compromises security and should only be |
| // used for debugging. |
| KeyLogWriter io.Writer |
| |
| serverInitOnce sync.Once // guards calling (*Config).serverInit |
| |
| // mutex protects sessionTicketKeys. |
| mutex sync.RWMutex |
| // sessionTicketKeys contains zero or more ticket keys. If the length |
| // is zero, SessionTicketsDisabled must be true. The first key is used |
| // for new tickets and any subsequent keys can be used to decrypt old |
| // tickets. |
| sessionTicketKeys []ticketKey |
| } |
| |
| // ticketKeyNameLen is the number of bytes of identifier that is prepended to |
| // an encrypted session ticket in order to identify the key used to encrypt it. |
| const ticketKeyNameLen = 16 |
| |
| // ticketKey is the internal representation of a session ticket key. |
| type ticketKey struct { |
| // keyName is an opaque byte string that serves to identify the session |
| // ticket key. It's exposed as plaintext in every session ticket. |
| keyName [ticketKeyNameLen]byte |
| aesKey [16]byte |
| hmacKey [16]byte |
| } |
| |
| // ticketKeyFromBytes converts from the external representation of a session |
| // ticket key to a ticketKey. Externally, session ticket keys are 32 random |
| // bytes and this function expands that into sufficient name and key material. |
| func ticketKeyFromBytes(b [32]byte) (key ticketKey) { |
| hashed := sha512.Sum512(b[:]) |
| copy(key.keyName[:], hashed[:ticketKeyNameLen]) |
| copy(key.aesKey[:], hashed[ticketKeyNameLen:ticketKeyNameLen+16]) |
| copy(key.hmacKey[:], hashed[ticketKeyNameLen+16:ticketKeyNameLen+32]) |
| return key |
| } |
| |
| // Clone returns a shallow clone of c. It is safe to clone a Config that is |
| // being used concurrently by a TLS client or server. |
| func (c *Config) Clone() *Config { |
| // Running serverInit ensures that it's safe to read |
| // SessionTicketsDisabled. |
| c.serverInitOnce.Do(func() { c.serverInit(nil) }) |
| |
| var sessionTicketKeys []ticketKey |
| c.mutex.RLock() |
| sessionTicketKeys = c.sessionTicketKeys |
| c.mutex.RUnlock() |
| |
| return &Config{ |
| Rand: c.Rand, |
| Time: c.Time, |
| Certificates: c.Certificates, |
| NameToCertificate: c.NameToCertificate, |
| GetCertificate: c.GetCertificate, |
| GetClientCertificate: c.GetClientCertificate, |
| GetConfigForClient: c.GetConfigForClient, |
| VerifyPeerCertificate: c.VerifyPeerCertificate, |
| RootCAs: c.RootCAs, |
| NextProtos: c.NextProtos, |
| ServerName: c.ServerName, |
| ClientAuth: c.ClientAuth, |
| ClientCAs: c.ClientCAs, |
| InsecureSkipVerify: c.InsecureSkipVerify, |
| CipherSuites: c.CipherSuites, |
| PreferServerCipherSuites: c.PreferServerCipherSuites, |
| SessionTicketsDisabled: c.SessionTicketsDisabled, |
| SessionTicketKey: c.SessionTicketKey, |
| ClientSessionCache: c.ClientSessionCache, |
| MinVersion: c.MinVersion, |
| MaxVersion: c.MaxVersion, |
| CurvePreferences: c.CurvePreferences, |
| DynamicRecordSizingDisabled: c.DynamicRecordSizingDisabled, |
| Renegotiation: c.Renegotiation, |
| KeyLogWriter: c.KeyLogWriter, |
| sessionTicketKeys: sessionTicketKeys, |
| } |
| } |
| |
| // serverInit is run under c.serverInitOnce to do initialization of c. If c was |
| // returned by a GetConfigForClient callback then the argument should be the |
| // Config that was passed to Server, otherwise it should be nil. |
| func (c *Config) serverInit(originalConfig *Config) { |
| if c.SessionTicketsDisabled || len(c.ticketKeys()) != 0 { |
| return |
| } |
| |
| alreadySet := false |
| for _, b := range c.SessionTicketKey { |
| if b != 0 { |
| alreadySet = true |
| break |
| } |
| } |
| |
| if !alreadySet { |
| if originalConfig != nil { |
| copy(c.SessionTicketKey[:], originalConfig.SessionTicketKey[:]) |
| } else if _, err := io.ReadFull(c.rand(), c.SessionTicketKey[:]); err != nil { |
| c.SessionTicketsDisabled = true |
| return |
| } |
| } |
| |
| if originalConfig != nil { |
| originalConfig.mutex.RLock() |
| c.sessionTicketKeys = originalConfig.sessionTicketKeys |
| originalConfig.mutex.RUnlock() |
| } else { |
| c.sessionTicketKeys = []ticketKey{ticketKeyFromBytes(c.SessionTicketKey)} |
| } |
| } |
| |
| func (c *Config) ticketKeys() []ticketKey { |
| c.mutex.RLock() |
| // c.sessionTicketKeys is constant once created. SetSessionTicketKeys |
| // will only update it by replacing it with a new value. |
| ret := c.sessionTicketKeys |
| c.mutex.RUnlock() |
| return ret |
| } |
| |
| // SetSessionTicketKeys updates the session ticket keys for a server. The first |
| // key will be used when creating new tickets, while all keys can be used for |
| // decrypting tickets. It is safe to call this function while the server is |
| // running in order to rotate the session ticket keys. The function will panic |
| // if keys is empty. |
| func (c *Config) SetSessionTicketKeys(keys [][32]byte) { |
| if len(keys) == 0 { |
| panic("tls: keys must have at least one key") |
| } |
| |
| newKeys := make([]ticketKey, len(keys)) |
| for i, bytes := range keys { |
| newKeys[i] = ticketKeyFromBytes(bytes) |
| } |
| |
| c.mutex.Lock() |
| c.sessionTicketKeys = newKeys |
| c.mutex.Unlock() |
| } |
| |
| 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 { |
| if needFIPS() { |
| return fipsCipherSuites(c) |
| } |
| s := c.CipherSuites |
| if s == nil { |
| s = defaultCipherSuites() |
| } |
| return s |
| } |
| |
| func (c *Config) minVersion() uint16 { |
| if needFIPS() { |
| return fipsMinVersion(c) |
| } |
| if c == nil || c.MinVersion == 0 { |
| return minVersion |
| } |
| return c.MinVersion |
| } |
| |
| func (c *Config) maxVersion() uint16 { |
| if needFIPS() { |
| return fipsMaxVersion(c) |
| } |
| if c == nil || c.MaxVersion == 0 { |
| return maxVersion |
| } |
| return c.MaxVersion |
| } |
| |
| var defaultCurvePreferences = []CurveID{X25519, CurveP256, CurveP384, CurveP521} |
| |
| func (c *Config) curvePreferences() []CurveID { |
| if needFIPS() { |
| return fipsCurvePreferences(c) |
| } |
| if c == nil || len(c.CurvePreferences) == 0 { |
| return defaultCurvePreferences |
| } |
| return c.CurvePreferences |
| } |
| |
| // mutualVersion returns the protocol version to use given the advertised |
| // version of the peer. |
| func (c *Config) mutualVersion(vers uint16) (uint16, bool) { |
| minVersion := c.minVersion() |
| maxVersion := c.maxVersion() |
| |
| if vers < minVersion { |
| return 0, false |
| } |
| if vers > maxVersion { |
| vers = maxVersion |
| } |
| return vers, true |
| } |
| |
| // getCertificate returns the best certificate for the given ClientHelloInfo, |
| // defaulting to the first element of c.Certificates. |
| func (c *Config) getCertificate(clientHello *ClientHelloInfo) (*Certificate, error) { |
| if c.GetCertificate != nil && |
| (len(c.Certificates) == 0 || len(clientHello.ServerName) > 0) { |
| cert, err := c.GetCertificate(clientHello) |
| if cert != nil || err != nil { |
| return cert, err |
| } |
| } |
| |
| if len(c.Certificates) == 0 { |
| return nil, errors.New("tls: no certificates configured") |
| } |
| |
| if len(c.Certificates) == 1 || c.NameToCertificate == nil { |
| // There's only one choice, so no point doing any work. |
| return &c.Certificates[0], nil |
| } |
| |
| name := strings.ToLower(clientHello.ServerName) |
| for len(name) > 0 && name[len(name)-1] == '.' { |
| name = name[:len(name)-1] |
| } |
| |
| if cert, ok := c.NameToCertificate[name]; ok { |
| return cert, nil |
| } |
| |
| // 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, nil |
| } |
| } |
| |
| // If nothing matches, return the first certificate. |
| return &c.Certificates[0], nil |
| } |
| |
| // 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 |
| } |
| } |
| } |
| |
| // writeKeyLog logs client random and master secret if logging was enabled by |
| // setting c.KeyLogWriter. |
| func (c *Config) writeKeyLog(clientRandom, masterSecret []byte) error { |
| if c.KeyLogWriter == nil { |
| return nil |
| } |
| |
| logLine := []byte(fmt.Sprintf("CLIENT_RANDOM %x %x\n", clientRandom, masterSecret)) |
| |
| writerMutex.Lock() |
| _, err := c.KeyLogWriter.Write(logLine) |
| writerMutex.Unlock() |
| |
| return err |
| } |
| |
| // writerMutex protects all KeyLogWriters globally. It is rarely enabled, |
| // and is only for debugging, so a global mutex saves space. |
| var writerMutex sync.Mutex |
| |
| // A Certificate is a chain of one or more certificates, leaf first. |
| type Certificate struct { |
| Certificate [][]byte |
| // PrivateKey contains the private key corresponding to the public key |
| // in Leaf. For a server, this must implement crypto.Signer and/or |
| // crypto.Decrypter, with an RSA or ECDSA PublicKey. For a client |
| // (performing client authentication), this must be a crypto.Signer |
| // with an RSA or ECDSA PublicKey. |
| PrivateKey crypto.PrivateKey |
| // OCSPStaple contains an optional OCSP response which will be served |
| // to clients that request it. |
| OCSPStaple []byte |
| // SignedCertificateTimestamps contains an optional list of Signed |
| // Certificate Timestamps which will be served to clients that request it. |
| SignedCertificateTimestamps [][]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 |
| } |
| |
| type handshakeMessage interface { |
| marshal() []byte |
| unmarshal([]byte) bool |
| } |
| |
| // lruSessionCache is a ClientSessionCache 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 *ClientSessionState |
| } |
| |
| // 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 &lruSessionCache{ |
| m: make(map[string]*list.Element), |
| q: list.New(), |
| capacity: capacity, |
| } |
| } |
| |
| // Put adds the provided (sessionKey, cs) pair to the cache. |
| func (c *lruSessionCache) Put(sessionKey string, cs *ClientSessionState) { |
| 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 ClientSessionState value associated with a given key. It |
| // returns (nil, false) if no value is found. |
| func (c *lruSessionCache) Get(sessionKey string) (*ClientSessionState, 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 |
| } |
| |
| // 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() { |
| var topCipherSuites []uint16 |
| if cipherhw.AESGCMSupport() { |
| // If AES-GCM hardware is provided then prioritise AES-GCM |
| // cipher suites. |
| topCipherSuites = []uint16{ |
| TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, |
| TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, |
| TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, |
| TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, |
| TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305, |
| TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, |
| } |
| } else { |
| // Without AES-GCM hardware, we put the ChaCha20-Poly1305 |
| // cipher suites first. |
| topCipherSuites = []uint16{ |
| TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305, |
| TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, |
| TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, |
| TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, |
| TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, |
| TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, |
| } |
| } |
| |
| varDefaultCipherSuites = make([]uint16, 0, len(cipherSuites)) |
| varDefaultCipherSuites = append(varDefaultCipherSuites, topCipherSuites...) |
| |
| NextCipherSuite: |
| for _, suite := range cipherSuites { |
| if suite.flags&suiteDefaultOff != 0 { |
| continue |
| } |
| for _, existing := range varDefaultCipherSuites { |
| if existing == suite.id { |
| continue NextCipherSuite |
| } |
| } |
| 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 isSupportedSignatureAndHash(sigHash signatureAndHash, sigHashes []signatureAndHash) bool { |
| for _, s := range sigHashes { |
| if s == sigHash { |
| return true |
| } |
| } |
| return false |
| } |