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Package tls

import "crypto/tls"
Overview
Index
Examples

Overview ▾

Package tls partially implements TLS 1.2, as specified in RFC 5246.

Index ▾

Constants
func Listen(network, laddr string, config *Config) (net.Listener, error)
func NewListener(inner net.Listener, config *Config) net.Listener
type Certificate
    func LoadX509KeyPair(certFile, keyFile string) (Certificate, error)
    func X509KeyPair(certPEMBlock, keyPEMBlock []byte) (Certificate, error)
type ClientAuthType
type ClientHelloInfo
type ClientSessionCache
    func NewLRUClientSessionCache(capacity int) ClientSessionCache
type ClientSessionState
type Config
    func (c *Config) BuildNameToCertificate()
    func (c *Config) SetSessionTicketKeys(keys [][32]byte)
type Conn
    func Client(conn net.Conn, config *Config) *Conn
    func Dial(network, addr string, config *Config) (*Conn, error)
    func DialWithDialer(dialer *net.Dialer, network, addr string, config *Config) (*Conn, error)
    func Server(conn net.Conn, config *Config) *Conn
    func (c *Conn) Close() error
    func (c *Conn) ConnectionState() ConnectionState
    func (c *Conn) Handshake() error
    func (c *Conn) LocalAddr() net.Addr
    func (c *Conn) OCSPResponse() []byte
    func (c *Conn) Read(b []byte) (n int, err error)
    func (c *Conn) RemoteAddr() net.Addr
    func (c *Conn) SetDeadline(t time.Time) error
    func (c *Conn) SetReadDeadline(t time.Time) error
    func (c *Conn) SetWriteDeadline(t time.Time) error
    func (c *Conn) VerifyHostname(host string) error
    func (c *Conn) Write(b []byte) (int, error)
type ConnectionState
type CurveID
type RecordHeaderError
    func (e RecordHeaderError) Error() string
type RenegotiationSupport
Bugs

Examples

Dial

Package files

alert.go cipher_suites.go common.go conn.go handshake_client.go handshake_messages.go handshake_server.go key_agreement.go prf.go ticket.go tls.go

Constants

A list of cipher suite IDs that are, or have been, implemented by this package.

Taken from http://www.iana.org/assignments/tls-parameters/tls-parameters.xml

const (
        TLS_RSA_WITH_RC4_128_SHA                uint16 = 0x0005
        TLS_RSA_WITH_3DES_EDE_CBC_SHA           uint16 = 0x000a
        TLS_RSA_WITH_AES_128_CBC_SHA            uint16 = 0x002f
        TLS_RSA_WITH_AES_256_CBC_SHA            uint16 = 0x0035
        TLS_RSA_WITH_AES_128_GCM_SHA256         uint16 = 0x009c
        TLS_RSA_WITH_AES_256_GCM_SHA384         uint16 = 0x009d
        TLS_ECDHE_ECDSA_WITH_RC4_128_SHA        uint16 = 0xc007
        TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA    uint16 = 0xc009
        TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA    uint16 = 0xc00a
        TLS_ECDHE_RSA_WITH_RC4_128_SHA          uint16 = 0xc011
        TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA     uint16 = 0xc012
        TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA      uint16 = 0xc013
        TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA      uint16 = 0xc014
        TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256   uint16 = 0xc02f
        TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 uint16 = 0xc02b
        TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384   uint16 = 0xc030
        TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 uint16 = 0xc02c

        // TLS_FALLBACK_SCSV isn't a standard cipher suite but an indicator
        // that the client is doing version fallback. See
        // https://tools.ietf.org/html/rfc7507.
        TLS_FALLBACK_SCSV uint16 = 0x5600
)
const (
        VersionSSL30 = 0x0300
        VersionTLS10 = 0x0301
        VersionTLS11 = 0x0302
        VersionTLS12 = 0x0303
)

func Listen

Listen creates a TLS listener accepting connections on the given network address using net.Listen. The configuration config must be non-nil and must include at least one certificate or else set GetCertificate.

func Listen(network, laddr string, config *Config) (net.Listener, error)

func NewListener

NewListener creates a Listener which accepts connections from an inner Listener and wraps each connection with Server. The configuration config must be non-nil and must include at least one certificate or else set GetCertificate.

func NewListener(inner net.Listener, config *Config) net.Listener

type Certificate

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
}

func LoadX509KeyPair

LoadX509KeyPair reads and parses a public/private key pair from a pair of files. The files must contain PEM encoded data. The certificate file may contain intermediate certificates following the leaf certificate to form a certificate chain. On successful return, Certificate.Leaf will be nil because the parsed form of the certificate is not retained.

func LoadX509KeyPair(certFile, keyFile string) (Certificate, error)

func X509KeyPair

X509KeyPair parses a public/private key pair from a pair of PEM encoded data. On successful return, Certificate.Leaf will be nil because the parsed form of the certificate is not retained.

func X509KeyPair(certPEMBlock, keyPEMBlock []byte) (Certificate, error)

type ClientAuthType

ClientAuthType declares the policy the server will follow for TLS Client Authentication.

type ClientAuthType int
const (
        NoClientCert ClientAuthType = iota
        RequestClientCert
        RequireAnyClientCert
        VerifyClientCertIfGiven
        RequireAndVerifyClientCert
)

type ClientHelloInfo

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
}

type ClientSessionCache

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)
}

func NewLRUClientSessionCache

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

type ClientSessionState

ClientSessionState contains the state needed by clients to resume TLS sessions.

type ClientSessionState struct {
        // contains filtered or unexported fields
}

type Config

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.
        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(clientHello *ClientHelloInfo) (*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
        // contains filtered or unexported fields
}

func (*Config) BuildNameToCertificate

BuildNameToCertificate parses c.Certificates and builds c.NameToCertificate from the CommonName and SubjectAlternateName fields of each of the leaf certificates.

func (c *Config) BuildNameToCertificate()

func (*Config) SetSessionTicketKeys

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)

type Conn

A Conn represents a secured connection. It implements the net.Conn interface.

type Conn struct {
        // contains filtered or unexported fields
}

func Client

Client returns a new TLS client side connection using conn as the underlying transport. The config cannot be nil: users must set either ServerName or InsecureSkipVerify in the config.

func Client(conn net.Conn, config *Config) *Conn

func Dial

Dial connects to the given network address using net.Dial and then initiates a TLS handshake, returning the resulting TLS connection. Dial interprets a nil configuration as equivalent to the zero configuration; see the documentation of Config for the defaults.

func Dial(network, addr string, config *Config) (*Conn, error)

Example

func DialWithDialer

DialWithDialer connects to the given network address using dialer.Dial and then initiates a TLS handshake, returning the resulting TLS connection. Any timeout or deadline given in the dialer apply to connection and TLS handshake as a whole.

DialWithDialer interprets a nil configuration as equivalent to the zero configuration; see the documentation of Config for the defaults.

func DialWithDialer(dialer *net.Dialer, network, addr string, config *Config) (*Conn, error)

func Server

Server returns a new TLS server side connection using conn as the underlying transport. The configuration config must be non-nil and must include at least one certificate or else set GetCertificate.

func Server(conn net.Conn, config *Config) *Conn

func (*Conn) Close

Close closes the connection.

func (c *Conn) Close() error

func (*Conn) ConnectionState

ConnectionState returns basic TLS details about the connection.

func (c *Conn) ConnectionState() ConnectionState

func (*Conn) Handshake

Handshake runs the client or server handshake protocol if it has not yet been run. Most uses of this package need not call Handshake explicitly: the first Read or Write will call it automatically.

func (c *Conn) Handshake() error

func (*Conn) LocalAddr

LocalAddr returns the local network address.

func (c *Conn) LocalAddr() net.Addr

func (*Conn) OCSPResponse

OCSPResponse returns the stapled OCSP response from the TLS server, if any. (Only valid for client connections.)

func (c *Conn) OCSPResponse() []byte

func (*Conn) Read

Read can be made to time out and return a net.Error with Timeout() == true after a fixed time limit; see SetDeadline and SetReadDeadline.

func (c *Conn) Read(b []byte) (n int, err error)

func (*Conn) RemoteAddr

RemoteAddr returns the remote network address.

func (c *Conn) RemoteAddr() net.Addr

func (*Conn) SetDeadline

SetDeadline sets the read and write deadlines associated with the connection. A zero value for t means Read and Write will not time out. After a Write has timed out, the TLS state is corrupt and all future writes will return the same error.

func (c *Conn) SetDeadline(t time.Time) error

func (*Conn) SetReadDeadline

SetReadDeadline sets the read deadline on the underlying connection. A zero value for t means Read will not time out.

func (c *Conn) SetReadDeadline(t time.Time) error

func (*Conn) SetWriteDeadline

SetWriteDeadline sets the write deadline on the underlying connection. A zero value for t means Write will not time out. After a Write has timed out, the TLS state is corrupt and all future writes will return the same error.

func (c *Conn) SetWriteDeadline(t time.Time) error

func (*Conn) VerifyHostname

VerifyHostname checks that the peer certificate chain is valid for connecting to host. If so, it returns nil; if not, it returns an error describing the problem.

func (c *Conn) VerifyHostname(host string) error

func (*Conn) Write

Write writes data to the connection.

func (c *Conn) Write(b []byte) (int, error)

type ConnectionState

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
        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://secure-resumption.com/#channelbindings). This will change in
        // future versions of Go once the TLS master-secret fix has been
        // standardized and implemented.
        TLSUnique []byte
}

type CurveID

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
)

type RecordHeaderError

RecordHeaderError results when a TLS record header is invalid.

type RecordHeaderError struct {
        // Msg contains a human readable string that describes the error.
        Msg string
        // RecordHeader contains the five bytes of TLS record header that
        // triggered the error.
        RecordHeader [5]byte
}

func (RecordHeaderError) Error

func (e RecordHeaderError) Error() string

type RenegotiationSupport

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
)

Bugs