/*
* Get the active protocol versions.
*
* In TLS 1.1, many weak or vulnerable cipher suites were obsoleted,
* such as TLS_RSA_EXPORT_WITH_RC4_40_MD5. The implementation MUST NOT
* negotiate these cipher suites in TLS 1.1 or later mode.
*
* For example, if "TLS_RSA_EXPORT_WITH_RC4_40_MD5" is the
* only enabled cipher suite, the client cannot request TLS 1.1 or
* later, even though TLS 1.1 or later is enabled. We need to create a
* subset of the enabled protocols, called the active protocols, which
* contains protocols appropriate to the list of enabled Ciphersuites.
*
* Return empty list instead of null if no active protocol versions.
*/
ProtocolList getActiveProtocols() {
if (activeProtocols == null) {
ArrayList<ProtocolVersion> protocols = new ArrayList<>(4);
for (ProtocolVersion protocol : enabledProtocols.collection()) {
boolean found = false;
for (CipherSuite suite : enabledCipherSuites.collection()) {
if (suite.isAvailable()
&& suite.obsoleted > protocol.v
&& suite.supported <= protocol.v) {
if (algorithmConstraints.permits(
EnumSet.of(CryptoPrimitive.KEY_AGREEMENT), suite.name, null)) {
protocols.add(protocol);
found = true;
break;
} else if (debug != null && Debug.isOn("verbose")) {
System.out.println("Ignoring disabled cipher suite: " + suite + " for " + protocol);
}
} else if (debug != null && Debug.isOn("verbose")) {
System.out.println("Ignoring unsupported cipher suite: " + suite + " for " + protocol);
}
}
if (!found && (debug != null) && Debug.isOn("handshake")) {
System.out.println("No available cipher suite for " + protocol);
}
}
activeProtocols = new ProtocolList(protocols);
}
return activeProtocols;
}
/**
* Check if the given ciphersuite is enabled and available. Does not check if the required server
* certificates are available.
*/
boolean isNegotiable(CipherSuite s) {
if (activeCipherSuites == null) {
activeCipherSuites = getActiveCipherSuites();
}
return activeCipherSuites.contains(s) && s.isNegotiable();
}
/**
* Get the active cipher suites.
*
* <p>In TLS 1.1, many weak or vulnerable cipher suites were obsoleted, such as
* TLS_RSA_EXPORT_WITH_RC4_40_MD5. The implementation MUST NOT negotiate these cipher suites in
* TLS 1.1 or later mode.
*
* <p>Therefore, when the active protocols only include TLS 1.1 or later, the client cannot
* request to negotiate those obsoleted cipher suites. That is, the obsoleted suites should not be
* included in the client hello. So we need to create a subset of the enabled cipher suites, the
* active cipher suites, which does not contain obsoleted cipher suites of the minimum active
* protocol.
*
* <p>Return empty list instead of null if no active cipher suites.
*/
CipherSuiteList getActiveCipherSuites() {
if (activeCipherSuites == null) {
if (activeProtocols == null) {
activeProtocols = getActiveProtocols();
}
ArrayList<CipherSuite> suites = new ArrayList<>();
if (!(activeProtocols.collection().isEmpty())
&& activeProtocols.min.v != ProtocolVersion.NONE.v) {
for (CipherSuite suite : enabledCipherSuites.collection()) {
if (suite.obsoleted > activeProtocols.min.v && suite.supported <= activeProtocols.max.v) {
if (algorithmConstraints.permits(
EnumSet.of(CryptoPrimitive.KEY_AGREEMENT), suite.name, null)) {
suites.add(suite);
}
} else if (debug != null && Debug.isOn("verbose")) {
if (suite.obsoleted <= activeProtocols.min.v) {
System.out.println("Ignoring obsoleted cipher suite: " + suite);
} else {
System.out.println("Ignoring unsupported cipher suite: " + suite);
}
}
}
}
activeCipherSuites = new CipherSuiteList(suites);
}
return activeCipherSuites;
}
/**
* Prior to handshaking, activate the handshake and initialize the version, input stream and
* output stream.
*/
void activate(ProtocolVersion helloVersion) throws IOException {
if (activeProtocols == null) {
activeProtocols = getActiveProtocols();
}
if (activeProtocols.collection().isEmpty() || activeProtocols.max.v == ProtocolVersion.NONE.v) {
throw new SSLHandshakeException("No appropriate protocol");
}
if (activeCipherSuites == null) {
activeCipherSuites = getActiveCipherSuites();
}
if (activeCipherSuites.collection().isEmpty()) {
throw new SSLHandshakeException("No appropriate cipher suite");
}
// temporary protocol version until the actual protocol version
// is negotiated in the Hello exchange. This affects the record
// version we sent with the ClientHello.
if (!isInitialHandshake) {
protocolVersion = activeProtocolVersion;
} else {
protocolVersion = activeProtocols.max;
}
if (helloVersion == null || helloVersion.v == ProtocolVersion.NONE.v) {
helloVersion = activeProtocols.helloVersion;
}
// We accumulate digests of the handshake messages so that
// we can read/write CertificateVerify and Finished messages,
// getting assurance against some particular active attacks.
Set<String> localSupportedHashAlgorithms =
SignatureAndHashAlgorithm.getHashAlgorithmNames(getLocalSupportedSignAlgs());
handshakeHash = new HandshakeHash(!isClient, needCertVerify, localSupportedHashAlgorithms);
// Generate handshake input/output stream.
input = new HandshakeInStream(handshakeHash);
if (conn != null) {
output = new HandshakeOutStream(protocolVersion, helloVersion, handshakeHash, conn);
conn.getAppInputStream().r.setHandshakeHash(handshakeHash);
conn.getAppInputStream().r.setHelloVersion(helloVersion);
conn.getAppOutputStream().r.setHelloVersion(helloVersion);
} else {
output = new HandshakeOutStream(protocolVersion, helloVersion, handshakeHash, engine);
engine.inputRecord.setHandshakeHash(handshakeHash);
engine.inputRecord.setHelloVersion(helloVersion);
engine.outputRecord.setHelloVersion(helloVersion);
}
// move state to activated
state = -1;
}