TLS (SSL)
Use require('tls')
to access this module.
The tls
module uses OpenSSL to provide Transport Layer Security and/or
Secure Socket Layer: encrypted stream communication.
TLS/SSL is a public/private key infrastructure. Each client and each server must have a private key. A private key is created like this
openssl genrsa -out ryans-key.pem 1024
All severs and some clients need to have a certificate. Certificates are public keys signed by a Certificate Authority or self-signed. The first step to getting a certificate is to create a "Certificate Signing Request" (CSR) file. This is done with:
openssl req -new -key ryans-key.pem -out ryans-csr.pem
To create a self-signed certificate with the CSR, do this:
openssl x509 -req -in ryans-csr.pem -signkey ryans-key.pem -out ryans-cert.pem
Alternatively you can send the CSR to a Certificate Authority for signing.
(TODO: docs on creating a CA, for now interested users should just look at
test/fixtures/keys/Makefile
in the Node source code)
tls.createServer(options, [secureConnectionListener])
Creates a new tls.Server.
The connectionListener
argument is automatically set as a listener for the
secureConnection event.
The options
object has these possibilities:
key
: A string orBuffer
containing the private key of the server in PEM format. (Required)passphrase
: A string of passphrase for the private key.cert
: A string orBuffer
containing the certificate key of the server in PEM format. (Required)ca
: An array of strings orBuffer
s of trusted certificates. If this is omitted several well known "root" CAs will be used, like VeriSign. These are used to authorize connections.requestCert
: Iftrue
the server will request a certificate from clients that connect and attempt to verify that certificate. Default:false
.rejectUnauthorized
: Iftrue
the server will reject any connection which is not authorized with the list of supplied CAs. This option only has an effect ifrequestCert
istrue
. Default:false
.NPNProtocols
: An array orBuffer
of possible NPN protocols. (Protocols should be ordered by their priority).SNICallback
: A function that will be called if client supports SNI TLS extension. Only one argument will be passed to it:servername
. AndSNICallback
should return SecureContext instance. (You can usecrypto.createCredentials(...).context
to get proper SecureContext). IfSNICallback
wasn't provided - default callback with high-level API will be used (see below).sessionIdContext
: A string containing a opaque identifier for session resumption. IfrequestCert
istrue
, the default is MD5 hash value generated from command-line. Otherwise, the default is not provided.
Here is a simple example echo server:
var tls = require('tls');
var fs = require('fs');
var options = {
key: fs.readFileSync('server-key.pem'),
cert: fs.readFileSync('server-cert.pem'),
// This is necessary only if using the client certificate authentication.
requestCert: true,
// This is necessary only if the client uses the self-signed certificate.
ca: [ fs.readFileSync('client-cert.pem') ]
};
var server = tls.createServer(options, function(cleartextStream) {
console.log('server connected',
cleartextStream.authorized ? 'authorized' : 'unauthorized');
cleartextStream.write("welcome!\n");
cleartextStream.setEncoding('utf8');
cleartextStream.pipe(cleartextStream);
});
server.listen(8000, function() {
console.log('server bound');
});
You can test this server by connecting to it with openssl s_client
:
openssl s_client -connect 127.0.0.1:8000
tls.connect(port, [host], [options], [secureConnectListener])
Creates a new client connection to the given port
and host
. (If host
defaults to localhost
.) options
should be an object which specifies
key
: A string orBuffer
containing the private key of the client in PEM format.passphrase
: A string of passphrase for the private key.cert
: A string orBuffer
containing the certificate key of the client in PEM format.ca
: An array of strings orBuffer
s of trusted certificates. If this is omitted several well known "root" CAs will be used, like VeriSign. These are used to authorize connections.NPNProtocols
: An array of string orBuffer
containing supported NPN protocols.Buffer
should have following format:0x05hello0x05world
, where first byte is next protocol name's length. (Passing array should usually be much simplier:['hello', 'world']
.)servername
: Servername for SNI (Server Name Indication) TLS extension.
The secureConnectListener
parameter will be added as a listener for the
'secureConnect' event.
tls.connect()
returns a CleartextStream object.
Here is an example of a client of echo server as described previously:
var tls = require('tls');
var fs = require('fs');
var options = {
// These are necessary only if using the client certificate authentication
key: fs.readFileSync('client-key.pem'),
cert: fs.readFileSync('client-cert.pem'),
// This is necessary only if the server uses the self-signed certificate
ca: [ fs.readFileSync('server-cert.pem') ]
};
var cleartextStream = tls.connect(8000, options, function() {
console.log('client connected',
cleartextStream.authorized ? 'authorized' : 'unauthorized');
process.stdin.pipe(cleartextStream);
process.stdin.resume();
});
cleartextStream.setEncoding('utf8');
cleartextStream.on('data', function(data) {
console.log(data);
});
cleartextStream.on('end', function() {
server.close();
});
Table of Contents #
STARTTLS #
In the v0.4 branch no function exists for starting a TLS session on an
already existing TCP connection. This is possible it just requires a bit of
work. The technique is to use tls.createSecurePair()
which returns two
streams: an encrypted stream and a cleartext stream. The encrypted stream is
then piped to the socket, the cleartext stream is what the user interacts with
thereafter.
Here is some code that does it.
NPN and SNI #
NPN (Next Protocol Negotitation) and SNI (Server Name Indication) are TLS handshake extensions allowing you:
- NPN - to use one TLS server for multiple protocols (HTTP, SPDY)
- SNI - to use one TLS server for multiple hostnames with different SSL certificates.
pair = tls.createSecurePair([credentials], [isServer], [requestCert], [rejectUnauthorized]) #
Creates a new secure pair object with two streams, one of which reads/writes encrypted data, and one reads/writes cleartext data. Generally the encrypted one is piped to/from an incoming encrypted data stream, and the cleartext one is used as a replacement for the initial encrypted stream.
credentials
: A credentials object from crypto.createCredentials( ... )isServer
: A boolean indicating whether this tls connection should be opened as a server or a client.requestCert
: A boolean indicating whether a server should request a certificate from a connecting client. Only applies to server connections.rejectUnauthorized
: A boolean indicating whether a server should automatically reject clients with invalid certificates. Only applies to servers withrequestCert
enabled.
tls.createSecurePair()
returns a SecurePair object with
cleartext and encrypted
stream properties.
Event: 'secure'
The event is emitted from the SecurePair once the pair has successfully established a secure connection.
Similarly to the checking for the server 'secureConnection' event, pair.cleartext.authorized should be checked to confirm whether the certificate used properly authorized.
tls.Server #
This class is a subclass of net.Server
and has the same methods on it.
Instead of accepting just raw TCP connections, this accepts encrypted
connections using TLS or SSL.
Event: 'secureConnection'
function (cleartextStream) {}
This event is emitted after a new connection has been successfully handshaked. The argument is a instance of CleartextStream. It has all the common stream methods and events.
cleartextStream.authorized
is a boolean value which indicates if the
client has verified by one of the supplied certificate authorities for the
server. If cleartextStream.authorized
is false, then
cleartextStream.authorizationError
is set to describe how authorization
failed. Implied but worth mentioning: depending on the settings of the TLS
server, you unauthorized connections may be accepted.
cleartextStream.npnProtocol
is a string containing selected NPN protocol.
cleartextStream.servername
is a string containing servername requested with
SNI.
server.listen(port, [host], [callback])
Begin accepting connections on the specified port
and host
. If the
host
is omitted, the server will accept connections directed to any
IPv4 address (INADDR_ANY
).
This function is asynchronous. The last parameter callback
will be called
when the server has been bound.
See net.Server
for more information.
server.close()
Stops the server from accepting new connections. This function is
asynchronous, the server is finally closed when the server emits a 'close'
event.
server.address()
Returns the bound address and port of the server as reported by the operating system. See net.Server.address() for more information.
server.addContext(hostname, credentials)
Add secure context that will be used if client request's SNI hostname is
matching passed hostname
(wildcards can be used). credentials
can contain
key
, cert
and ca
.
server.maxConnections
Set this property to reject connections when the server's connection count gets high.
server.connections
The number of concurrent connections on the server.
tls.CleartextStream #
This is a stream on top of the Encrypted stream that makes it possible to read/write an encrypted data as a cleartext data.
This instance implements a duplex Stream interfaces. It has all the common stream methods and events.
Event: 'secureConnect'
function () {}
This event is emitted after a new connection has been successfully handshaked.
The listener will be called no matter if the server's certificate was
authorized or not. It is up to the user to test cleartextStream.authorized
to see if the server certificate was signed by one of the specified CAs.
If cleartextStream.authorized === false
then the error can be found in
cleartextStream.authorizationError
. Also if NPN was used - you can check
cleartextStream.npnProtocol
for negotiated protocol.
cleartextStream.authorized
A boolean that is true
if the peer certificate was signed by one of the
specified CAs, otherwise false
cleartextStream.authorizationError
The reason why the peer's certificate has not been verified. This property
becomes available only when cleartextStream.authorized === false
.
cleartextStream.getPeerCertificate()
Returns an object representing the peer's certicicate. The returned object has some properties corresponding to the field of the certificate.
Example:
{ subject:
{ C: 'UK',
ST: 'Acknack Ltd',
L: 'Rhys Jones',
O: 'node.js',
OU: 'Test TLS Certificate',
CN: 'localhost' },
issuer:
{ C: 'UK',
ST: 'Acknack Ltd',
L: 'Rhys Jones',
O: 'node.js',
OU: 'Test TLS Certificate',
CN: 'localhost' },
valid_from: 'Nov 11 09:52:22 2009 GMT',
valid_to: 'Nov 6 09:52:22 2029 GMT',
fingerprint: '2A:7A:C2:DD:E5:F9:CC:53:72:35:99:7A:02:5A:71:38:52:EC:8A:DF' }
If the peer does not provide a certificate, it returns null
or an empty
object.
cleartextStream.address()
Returns the bound address and port of the underlying socket as reported by the
operating system. Returns an object with two properties, e.g.
{"address":"192.168.57.1", "port":62053}
cleartextStream.remoteAddress
The string representation of the remote IP address. For example,
'74.125.127.100'
or '2001:4860:a005::68'
.
cleartextStream.remotePort
The numeric representation of the remote port. For example, 443
.
Documentation generated by mdoc.