The TLS versions configured in a connection spec are only be used if they are also enabled in * the SSL socket. For example, if an SSL socket does not have TLS 1.2 enabled, it will not be used * even if it is present on the connection spec. The same policy also applies to cipher suites. * *
Use {@link Builder#allEnabledTlsVersions()} and {@link Builder#allEnabledCipherSuites} to
* defer all feature selection to the underlying SSL socket.
* @hide This class is not part of the Android public SDK API
*/
public final class ConnectionSpec {
// This is a subset of the cipher suites supported in Chrome 46, current as of 2015-11-05.
// All of these suites are available on Android 5.0; earlier releases support a subset of
// these suites. https://github.com/square/okhttp/issues/330
private static final CipherSuite[] APPROVED_CIPHER_SUITES = new CipherSuite[] {
CipherSuite.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
CipherSuite.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
CipherSuite.TLS_DHE_RSA_WITH_AES_128_GCM_SHA256,
// Note that the following cipher suites are all on HTTP/2's bad cipher suites list. We'll
// continue to include them until better suites are commonly available. For example, none
// of the better cipher suites listed above shipped with Android 4.4 or Java 7.
CipherSuite.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
CipherSuite.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
CipherSuite.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
CipherSuite.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
CipherSuite.TLS_DHE_RSA_WITH_AES_128_CBC_SHA,
CipherSuite.TLS_DHE_RSA_WITH_AES_256_CBC_SHA,
CipherSuite.TLS_RSA_WITH_AES_128_GCM_SHA256,
CipherSuite.TLS_RSA_WITH_AES_128_CBC_SHA,
CipherSuite.TLS_RSA_WITH_AES_256_CBC_SHA,
CipherSuite.TLS_RSA_WITH_3DES_EDE_CBC_SHA,
};
/** A modern TLS connection with extensions like SNI and ALPN available. */
public static final ConnectionSpec MODERN_TLS = new Builder(true)
.cipherSuites(APPROVED_CIPHER_SUITES)
.tlsVersions(TlsVersion.TLS_1_2, TlsVersion.TLS_1_1, TlsVersion.TLS_1_0)
.supportsTlsExtensions(true)
.build();
/** A backwards-compatible fallback connection for interop with obsolete servers. */
public static final ConnectionSpec COMPATIBLE_TLS = new Builder(MODERN_TLS)
.tlsVersions(TlsVersion.TLS_1_0)
.supportsTlsExtensions(true)
.build();
/** Unencrypted, unauthenticated connections for {@code http:} URLs. */
public static final ConnectionSpec CLEARTEXT = new Builder(false).build();
private final boolean tls;
private final boolean supportsTlsExtensions;
private final String[] cipherSuites;
private final String[] tlsVersions;
private ConnectionSpec(Builder builder) {
this.tls = builder.tls;
this.cipherSuites = builder.cipherSuites;
this.tlsVersions = builder.tlsVersions;
this.supportsTlsExtensions = builder.supportsTlsExtensions;
}
public boolean isTls() {
return tls;
}
/**
* Returns the cipher suites to use for a connection. Returns {@code null} if all of the SSL
* socket's enabled cipher suites should be used.
*/
public List For cipher suites, at least one of the {@link #cipherSuites() required cipher suites} must
* match the socket's enabled cipher suites. If there are no required cipher suites the socket
* must have at least one cipher suite enabled.
*
* For protocols, at least one of the {@link #tlsVersions() required protocols} must match the
* socket's enabled protocols.
*/
public boolean isCompatible(SSLSocket socket) {
if (!tls) {
return false;
}
if (tlsVersions != null
&& !nonEmptyIntersection(tlsVersions, socket.getEnabledProtocols())) {
return false;
}
if (cipherSuites != null
&& !nonEmptyIntersection(cipherSuites, socket.getEnabledCipherSuites())) {
return false;
}
return true;
}
/**
* An N*M intersection that terminates if any intersection is found. The sizes of both
* arguments are assumed to be so small, and the likelihood of an intersection so great, that it
* is not worth the CPU cost of sorting or the memory cost of hashing.
*/
private static boolean nonEmptyIntersection(String[] a, String[] b) {
if (a == null || b == null || a.length == 0 || b.length == 0) {
return false;
}
for (String toFind : a) {
if (contains(b, toFind)) {
return true;
}
}
return false;
}
@Override public boolean equals(Object other) {
if (!(other instanceof ConnectionSpec)) return false;
if (other == this) return true;
ConnectionSpec that = (ConnectionSpec) other;
if (this.tls != that.tls) return false;
if (tls) {
if (!Arrays.equals(this.cipherSuites, that.cipherSuites)) return false;
if (!Arrays.equals(this.tlsVersions, that.tlsVersions)) return false;
if (this.supportsTlsExtensions != that.supportsTlsExtensions) return false;
}
return true;
}
@Override public int hashCode() {
int result = 17;
if (tls) {
result = 31 * result + Arrays.hashCode(cipherSuites);
result = 31 * result + Arrays.hashCode(tlsVersions);
result = 31 * result + (supportsTlsExtensions ? 0 : 1);
}
return result;
}
@Override public String toString() {
if (!tls) {
return "ConnectionSpec()";
}
String cipherSuitesString = cipherSuites != null ? cipherSuites().toString() : "[all enabled]";
String tlsVersionsString = tlsVersions != null ? tlsVersions().toString() : "[all enabled]";
return "ConnectionSpec("
+ "cipherSuites=" + cipherSuitesString
+ ", tlsVersions=" + tlsVersionsString
+ ", supportsTlsExtensions=" + supportsTlsExtensions
+ ")";
}
/**
* @hide This class is not part of the Android public SDK API
*/
public static final class Builder {
private boolean tls;
private String[] cipherSuites;
private String[] tlsVersions;
private boolean supportsTlsExtensions;
Builder(boolean tls) {
this.tls = tls;
}
public Builder(ConnectionSpec connectionSpec) {
this.tls = connectionSpec.tls;
this.cipherSuites = connectionSpec.cipherSuites;
this.tlsVersions = connectionSpec.tlsVersions;
this.supportsTlsExtensions = connectionSpec.supportsTlsExtensions;
}
public Builder allEnabledCipherSuites() {
if (!tls) throw new IllegalStateException("no cipher suites for cleartext connections");
this.cipherSuites = null;
return this;
}
public Builder cipherSuites(CipherSuite... cipherSuites) {
if (!tls) throw new IllegalStateException("no cipher suites for cleartext connections");
String[] strings = new String[cipherSuites.length];
for (int i = 0; i < cipherSuites.length; i++) {
strings[i] = cipherSuites[i].javaName;
}
return cipherSuites(strings);
}
public Builder cipherSuites(String... cipherSuites) {
if (!tls) throw new IllegalStateException("no cipher suites for cleartext connections");
if (cipherSuites.length == 0) {
throw new IllegalArgumentException("At least one cipher suite is required");
}
this.cipherSuites = cipherSuites.clone(); // Defensive copy.
return this;
}
public Builder allEnabledTlsVersions() {
if (!tls) throw new IllegalStateException("no TLS versions for cleartext connections");
this.tlsVersions = null;
return this;
}
public Builder tlsVersions(TlsVersion... tlsVersions) {
if (!tls) throw new IllegalStateException("no TLS versions for cleartext connections");
String[] strings = new String[tlsVersions.length];
for (int i = 0; i < tlsVersions.length; i++) {
strings[i] = tlsVersions[i].javaName;
}
return tlsVersions(strings);
}
public Builder tlsVersions(String... tlsVersions) {
if (!tls) throw new IllegalStateException("no TLS versions for cleartext connections");
if (tlsVersions.length == 0) {
throw new IllegalArgumentException("At least one TLS version is required");
}
this.tlsVersions = tlsVersions.clone(); // Defensive copy.
return this;
}
public Builder supportsTlsExtensions(boolean supportsTlsExtensions) {
if (!tls) throw new IllegalStateException("no TLS extensions for cleartext connections");
this.supportsTlsExtensions = supportsTlsExtensions;
return this;
}
public ConnectionSpec build() {
return new ConnectionSpec(this);
}
}
}