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A utility to add certs to the trust store from a connection attempt, originially written by Oracle
package usn.net.ssl.util;
import java.io.IOException;
import java.net.Socket;
/**
* A STARTTLS protocol extension wrapper class that makes an effort to decide on
* the application protocol to try and runs an appropriate protocol handler.
*/
public class Starttls {
// TODO implement NNTP/STARTTLS (119) some day...
// TODO implement XMPP/STARTTLS (5222) some day...
/**
* Enumeration of known application-level TCP-based protocols that support
* STARTTLS extension, with their standard port numbers.
*/
public enum Protocol {
SMTP(25),
POP3(110),
IMAP(143),
LDAP(389),
LDAPS(636),
LDAPGC(3268),
LDAPGCS(3269),
POSTGRES(5432);
/**
* The standard port for a protocol
*/
int port;
/**
* The constructor for a given standard port
*
* @param port the standard port for a protocol
*/
Protocol(int port) {
this.port = port;
} // Protocols
/**
* Guess a protocol with given port number
*
* @param port the port number to try
* @return a {@link Protocol} enumeration constant, or null
* if no appropriate protocol found
*/
static public Starttls.Protocol getByPort(int port) {
for (Starttls.Protocol p : Protocol.values()) {
if (p.port == port) {
return p;
}
}
return null;
} // getByPort
} // enum Protocol
/**
* Make an effort to guess the right application protocol for STARTTLS
* extension, either by standard port or by interrogating the user; then
* obtain the appropriate protocol handler and run it.
*
* @param host the host to connect to
* @param port the port to connect to
* @return true if getting a certificate via STARTTLS handler
* is believed to be successful, false otherwise
* @throws IOException
*/
public static boolean consider(String host, int port, Socket proxyTunnel)
throws IOException, Exception {
Starttls.Protocol protocolForPort = Protocol.getByPort(port);
if (protocolForPort != null) {
return obtainProtocolHandlerAndRun(protocolForPort.name(), host, port, proxyTunnel);
} else {
//let's just try everything
Protocol[] vals = Protocol.values();
for (int i = 0; i < vals.length; i++) {
if (obtainProtocolHandlerAndRun(vals[i].name(), host, port,proxyTunnel)) {
return true;
}
}
return false;
}
} // consider
/**
* Load a given application specific protocol STARTTLS handler and run it.
*
* @param handlerSuffix the protocol handler name suffix, named after
* protocol itself
* @param host the host to connect to
* @param port the port to connect to
* @return true if getting a certificate via STARTTLS handler
* is believed to be successful, false otherwise
*/
private static boolean obtainProtocolHandlerAndRun(String handlerSuffix, String host, int port, Socket proxyTunnel) throws Exception {
Class handlerClass = null;
try {
// avoid static linking to JavaMail library and other
// protocol-specific libraries
@SuppressWarnings("unchecked")
Class handlerUncheckedClass
= (Class) Class.forName(StarttlsHandler.class.getName() + handlerSuffix);
handlerClass = handlerUncheckedClass;
} catch (ClassNotFoundException e) {
// not really observed, but we should expect may happen...
throw e;
} catch (NoClassDefFoundError e) {
if (e.getCause().getClass()
.equals(ClassNotFoundException.class)
&& e.getCause().getMessage()
.equals("javax.mail.NoSuchProviderException")) {
System.out.println("ERROR loading protocol-specific STARTTLS handler: "
+ e.toString());
System.out.println("Looks like you need to make JavaMail library "
+ "available on your classpath, something like this:\n"
+ " java -cp " + System.getProperty("java.class.path")
+ System.getProperty("path.separator") + "..."
+ System.getProperty("file.separator") + "javax.mail.jar "
+ "usn.net.ssl.util.InstallCert ");
throw e;
} else {
// provide more info for analysis...
throw e;
}
}
StarttlsHandler handler = null;
try {
handler = handlerClass.newInstance();
} catch (InstantiationException e) {
// should not happen...
e.printStackTrace();
return false;
} catch (IllegalAccessException e) {
// should not happen...
e.printStackTrace();
return false;
}
return handler.run(host, port, proxyTunnel);
} // obtainProtocolHandlerAndRun
} // class Starttls