tls

Documentation

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

Examples

• Dial

Constants

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/draft-ietf-tls-downgrade-scsv-00.
	TLS_FALLBACK_SCSV uint16 = 0x5600
)

A list of the possible cipher suite ids. Taken from http://www.iana.org/assignments/tls-parameters/tls-parameters.xml

const (
	VersionSSL30 = 0x0300
	VersionTLS10 = 0x0301
	VersionTLS11 = 0x0302
	VersionTLS12 = 0x0303
)

Functions

func Listen

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

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 NewListener

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

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.

Types

type Certificate

type Certificate struct {
	Certificate [][]byte

	PrivateKey crypto.PrivateKey

	OCSPStaple []byte

	SignedCertificateTimestamps [][]byte

	Leaf *x509.Certificate
}

A Certificate is a chain of one or more certificates, leaf first.

func LoadX509KeyPair

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

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

func X509KeyPair

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

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.

type ClientAuthType

type ClientAuthType int

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

const (
	NoClientCert ClientAuthType = iota
	RequestClientCert
	RequireAnyClientCert
	VerifyClientCertIfGiven
	RequireAndVerifyClientCert
)

type ClientHelloInfo

type ClientHelloInfo struct {
	CipherSuites []uint16

	ServerName string

	SupportedCurves []CurveID

	SupportedPoints []uint8
}

ClientHelloInfo contains information from a ClientHello message in order to guide certificate selection in the GetCertificate callback.

type ClientSessionCache

type ClientSessionCache interface {
	Get(sessionKey string) (session *ClientSessionState, ok bool)

	Put(sessionKey string, cs *ClientSessionState)
}

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.

func NewLRUClientSessionCache

func NewLRUClientSessionCache(capacity int) ClientSessionCache

NewLRUClientSessionCache returns a ClientSessionCache with the given capacity that uses an LRU strategy. If capacity is < 1, a default capacity is used instead.

type ClientSessionState

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

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

type Config

type Config struct {
	Rand io.Reader

	Time func() time.Time

	Certificates []Certificate

	NameToCertificate map[string]*Certificate

	GetCertificate func(clientHello *ClientHelloInfo) (*Certificate, error)

	RootCAs *x509.CertPool

	NextProtos []string

	ServerName string

	ClientAuth ClientAuthType

	ClientCAs *x509.CertPool

	InsecureSkipVerify bool

	CipherSuites []uint16

	PreferServerCipherSuites bool

	SessionTicketsDisabled bool

	SessionTicketKey [32]byte

	ClientSessionCache ClientSessionCache

	MinVersion uint16

	MaxVersion uint16

	CurvePreferences []CurveID
	// contains filtered or unexported fields
}

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.

func (*Config) BuildNameToCertificate

func (c *Config) BuildNameToCertificate()

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

func (*Config) SetSessionTicketKeys

func (c *Config) SetSessionTicketKeys(keys [][32]byte)

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.

type Conn

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

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

func Client

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

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 Dial

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

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.

Example

package main

import (
	"crypto/tls"
	"crypto/x509"
)

func main() {
	// Connecting with a custom root-certificate set.

	const rootPEM = `
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----`

	// First, create the set of root certificates. For this example we only
	// have one. It's also possible to omit this in order to use the
	// default root set of the current operating system.
	roots := x509.NewCertPool()
	ok := roots.AppendCertsFromPEM([]byte(rootPEM))
	if !ok {
		panic("failed to parse root certificate")
	}

	conn, err := tls.Dial("tcp", "mail.google.com:443", &tls.Config{
		RootCAs: roots,
	})
	if err != nil {
		panic("failed to connect: " + err.Error())
	}
	conn.Close()
}

func DialWithDialer

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

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 Server

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

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 (*Conn) Close

func (c *Conn) Close() error

Close closes the connection.

func (*Conn) ConnectionState

func (c *Conn) ConnectionState() ConnectionState

ConnectionState returns basic TLS details about the connection.

func (*Conn) Handshake

func (c *Conn) Handshake() error

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 (*Conn) LocalAddr

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

LocalAddr returns the local network address.

func (*Conn) OCSPResponse

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

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

func (*Conn) Read

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

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 (*Conn) RemoteAddr

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

RemoteAddr returns the remote network address.

func (*Conn) SetDeadline

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

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 (*Conn) SetReadDeadline

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

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

func (*Conn) SetWriteDeadline

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

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 (*Conn) VerifyHostname

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

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 (*Conn) Write

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

Write writes data to the connection.

type ConnectionState

type ConnectionState struct {
	Version                     uint16
	HandshakeComplete           bool
	DidResume                   bool
	CipherSuite                 uint16
	NegotiatedProtocol          string
	NegotiatedProtocolIsMutual  bool
	ServerName                  string
	PeerCertificates            []*x509.Certificate
	VerifiedChains              [][]*x509.Certificate
	SignedCertificateTimestamps [][]byte
	OCSPResponse                []byte

	TLSUnique []byte
}

ConnectionState records basic TLS details about the connection.

type CurveID

type CurveID uint16

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

const (
	CurveP256 CurveID = 23
	CurveP384 CurveID = 24
	CurveP521 CurveID = 25
)

type RecordHeaderError

type RecordHeaderError struct {
	Msg string

	RecordHeader [5]byte
}

RecordHeaderError results when a TLS record header is invalid.

func (RecordHeaderError) Error

func (e RecordHeaderError) Error() string