tls

package
v1.9.0 Latest Latest
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 Go to latest Published: Sep 26, 2023 License: MIT Imports: 7 Imported by: 0

Documentation

Overview

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

Index

Examples

Constants

View Source 
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_CBC_SHA256         uint16 = 0x003c
	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_ECDSA_WITH_AES_128_CBC_SHA256 uint16 = 0xc023
	TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256   uint16 = 0xc027
	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_ECDHE_RSA_WITH_CHACHA20_POLY1305    uint16 = 0xcca8
	TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305  uint16 = 0xcca9

	// 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
)

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

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

Variables

This section is empty.

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. 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 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 CertificateRequestInfo added in v1.8.0 

type CertificateRequestInfo struct {
	AcceptableCAs [][]byte

	SignatureSchemes []SignatureScheme
}

CertificateRequestInfo contains information from a server's CertificateRequest message, which is used to demand a certificate and proof of control from a client.

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 added in v1.4.0 

type ClientHelloInfo struct {
	CipherSuites []uint16

	ServerName string

	SupportedCurves []CurveID

	SupportedPoints []uint8

	SignatureSchemes []SignatureScheme

	SupportedProtos []string

	SupportedVersions []uint16

	Conn net.Conn
}

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

type ClientSessionCache added in v1.3.0 

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. Only ticket-based resumption is supported, not SessionID-based resumption.

func NewLRUClientSessionCache added in v1.3.0 

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 added in v1.3.0 

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(*ClientHelloInfo) (*Certificate, error)

	GetClientCertificate func(*CertificateRequestInfo) (*Certificate, error)

	GetConfigForClient func(*ClientHelloInfo) (*Config, error)

	VerifyPeerCertificate func(rawCerts [][]byte, verifiedChains [][]*x509.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

	DynamicRecordSizingDisabled bool

	Renegotiation RenegotiationSupport

	KeyLogWriter io.Writer
	// 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.

Example (KeyLogWriter) 
// Debugging TLS applications by decrypting a network traffic capture.

// WARNING: Use of KeyLogWriter compromises security and should only be
// used for debugging.

// Dummy test HTTP server for the example with insecure random so output is
// reproducible.
server := httptest.NewUnstartedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {}))
server.TLS = &tls.Config{
	Rand: zeroSource{}, // for example only; don't do this.
}
server.StartTLS()
defer server.Close()

// Typically the log would go to an open file:
// w, err := os.OpenFile("tls-secrets.txt", os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
w := os.Stdout

client := &http.Client{
	Transport: &http.Transport{
		TLSClientConfig: &tls.Config{
			KeyLogWriter: w,

			Rand:               zeroSource{}, // for reproducible output; don't do this.
			InsecureSkipVerify: true,         // test server certificate is not trusted.
		},
	},
}
resp, err := client.Get(server.URL)
if err != nil {
	log.Fatalf("Failed to get URL: %v", err)
}
resp.Body.Close()

// The resulting file can be used with Wireshark to decrypt the TLS
// connection by setting (Pre)-Master-Secret log filename in SSL Protocol
// preferences.

Output:

CLIENT_RANDOM 0000000000000000000000000000000000000000000000000000000000000000 baca0df460a688e44ce018b025183cc2353ae01f89755ef766eedd3ecc302888ee3b3a22962e45f48c20df15a98c0e80

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) Clone added in v1.8.0 

func (c *Config) Clone() *Config

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 (*Config) SetSessionTicketKeys added in v1.5.0 

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()
}

Output:

func DialWithDialer added in v1.3.0 

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) CloseWrite added in v1.8.0 

func (c *Conn) CloseWrite() error

CloseWrite shuts down the writing side of the connection. It should only be called once the handshake has completed and does not call CloseWrite on the underlying connection. Most callers should just use Close.

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 added in v1.3.0 

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
	X25519    CurveID = 29
)

type RecordHeaderError added in v1.6.0 

type RecordHeaderError struct {
	Msg string

	RecordHeader [5]byte
}

RecordHeaderError results when a TLS record header is invalid.

func (RecordHeaderError) Error added in v1.6.0 

func (e RecordHeaderError) Error() string

type RenegotiationSupport added in v1.7.0 

type RenegotiationSupport int

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. 

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
)

type SignatureScheme added in v1.8.0 

type SignatureScheme uint16

SignatureScheme identifies a signature algorithm supported by TLS. See https://tools.ietf.org/html/draft-ietf-tls-tls13-18#section-4.2.3. 

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
)

Source Files

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