A global object containing build-specific properties that affect the * behaviour of the generated binaries from this library.
* * @version $Revision: 1.7 $ */ public final class Properties { // Debugging methods and variables // ------------------------------------------------------------------------- private static final String NAME = "Properties"; private static final boolean DEBUG = true; // private static final int debuglevel = 9; private static final PrintWriter err = new PrintWriter(System.out, true); private static void debug(final String s) { err.println(">>> "+NAME+": "+s); } // Constants and variables // ------------------------------------------------------------------------- public static final String PROPERTIES_FILE = "gnu.crypto.properties.file"; public static final String REPRODUCIBLE_PRNG = "gnu.crypto.with.reproducible.prng"; public static final String CHECK_WEAK_KEYS = "gnu.crypto.with.check.for.weak.keys"; public static final String DO_RSA_BLINDING = "gnu.crypto.with.rsa.blinding"; private static final String TRUE = Boolean.TRUE.toString(); private static final String FALSE = Boolean.FALSE.toString(); private static final HashMap props = new HashMap(); private static Properties singleton = null; private boolean reproducible = false; private boolean checkForWeakKeys = true; private boolean doRSABlinding = true; // Constructor(s) // ------------------------------------------------------------------------- /** Trivial constructor to enforce Singleton pattern. */ private Properties() { super(); init(); } // Class methods // ------------------------------------------------------------------------- /** *Returns the string representation of the library global configuration
* property with the designated key.
null if such property is not yet set, or key is
* empty.
*/
public static synchronized final String getProperty(String key) {
if (key == null) {
return null;
}
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(new PropertyPermission(key, "read"));
}
key = key.trim().toLowerCase();
if ("".equals(key)) {
return null;
}
return (String) props.get(key);
}
/**
* Sets the value of a designated library global configuration property, * to a string representation of what should be a legal value.
* * @param key the case-insensitive, non-null and non-empty name of a * configuration property. * @param value the non-null, non-empty string representation of a legal * value of the configuration property named bykey.
*/
public static synchronized final void setProperty(String key, String value) {
if (key == null || value == null) {
return;
}
key = key.trim().toLowerCase();
if ("".equals(key)) {
return;
}
value = value.trim();
if ("".equals(value)) {
return;
}
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(new PropertyPermission(key, "write"));
}
if (key.equals(REPRODUCIBLE_PRNG)
&& (value.equalsIgnoreCase(TRUE) || value.equalsIgnoreCase(FALSE))) {
setReproducible(Boolean.valueOf(value).booleanValue());
} else if (key.equals(CHECK_WEAK_KEYS)
&& (value.equalsIgnoreCase(TRUE) || value.equalsIgnoreCase(FALSE))) {
setCheckForWeakKeys(Boolean.valueOf(value).booleanValue());
} else if (key.equals(DO_RSA_BLINDING)
&& (value.equalsIgnoreCase(TRUE) || value.equalsIgnoreCase(FALSE))) {
setDoRSABlinding(Boolean.valueOf(value).booleanValue());
} else {
props.put(key, value);
}
}
/**
* A convenience method that returns, as a boolean, the library global * configuration property indicating if the default Pseudo Random Number * Generator produces, or not, the same bit stream when instantiated.
* * @returntrue if the default PRNG produces the same bit stream
* with every VM instance. Returns false if the default PRNG is
* seeded with the time of day of its first invocation.
*/
public static synchronized final boolean isReproducible() {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(new PropertyPermission(REPRODUCIBLE_PRNG, "read"));
}
return instance().reproducible;
}
/**
* A convenience method that returns, as a boolean, the library global * configuration property indicating if the implementations of symmetric * key block ciphers check, or not, for possible/potential weak and semi-weak * keys that may be produced in the course of generating round encryption * and/or decryption keys.
* * @returntrue if the cipher implementations check for weak and
* semi-weak keys. Returns false if the cipher implementations
* do not check for weak or semi-weak keys.
*/
public static synchronized final boolean checkForWeakKeys() {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(new PropertyPermission(CHECK_WEAK_KEYS, "read"));
}
return instance().checkForWeakKeys;
}
/**
* A convenience method that returns, as a boolean, the library global * configuration property indicating if RSA decryption (RSADP primitive), * does, or not, blinding against timing attacks.
* * @returntrue if the RSA decryption primitive includes a
* blinding operation. Returns false if the RSA decryption
* primitive does not include the additional blinding operation.
*/
public static synchronized final boolean doRSABlinding() {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(new PropertyPermission(DO_RSA_BLINDING, "read"));
}
return instance().doRSABlinding;
}
/**
* A convenience method to set the global property for reproducibility of * the default PRNG bit stream output.
* * @param value iftrue then the default PRNG bit stream output
* is the same with every invocation of the VM.
*/
public static synchronized final void setReproducible(final boolean value) {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(new PropertyPermission(REPRODUCIBLE_PRNG, "write"));
}
instance().reproducible = value;
props.put(REPRODUCIBLE_PRNG, String.valueOf(value));
}
/**
* A convenience method to set the global property for checking for weak * and semi-weak cipher keys.
* * @param value iftrue then the cipher implementations will
* invoke additional checks for weak and semi-weak key values that may get
* generated.
*/
public static synchronized final void setCheckForWeakKeys(final boolean value) {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(new PropertyPermission(CHECK_WEAK_KEYS, "write"));
}
instance().checkForWeakKeys = value;
props.put(CHECK_WEAK_KEYS, String.valueOf(value));
}
/**
* A convenience method to set the global property fo adding a blinding * operation when executing the RSA decryption primitive.
* * @param value iftrue then the code for performing the RSA
* decryption primitive will include a blinding operation.
*/
public static synchronized final void setDoRSABlinding(final boolean value) {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(new PropertyPermission(DO_RSA_BLINDING, "write"));
}
instance().doRSABlinding = value;
props.put(DO_RSA_BLINDING, String.valueOf(value));
}
private static synchronized final Properties instance() {
if (singleton == null) {
singleton = new Properties();
}
return singleton;
}
// Instance methods
// -------------------------------------------------------------------------
private void init() {
// default values
props.put(REPRODUCIBLE_PRNG, new Boolean(reproducible).toString());
props.put(CHECK_WEAK_KEYS, new Boolean(checkForWeakKeys).toString());
props.put(DO_RSA_BLINDING, new Boolean(doRSABlinding).toString());
// 1. allow site-wide override by reading a properties file
String propFile = null;
try {
propFile = (String) AccessController.doPrivileged(
new PrivilegedAction() {
public Object run() {
return System.getProperty(PROPERTIES_FILE);
}
}
);
} catch (SecurityException se) {
if (DEBUG) debug("Reading property "+PROPERTIES_FILE+" not allowed. Ignored.");
}
if (propFile != null) {
try {
final java.util.Properties temp = new java.util.Properties();
final FileInputStream fin = new FileInputStream(propFile);
temp.load(fin);
temp.list(System.out);
props.putAll(temp);
} catch (IOException ioe) {
if (DEBUG) debug("IO error reading "+propFile+": "+ioe.getMessage());
} catch (SecurityException se) {
if (DEBUG) debug("Security error reading "+propFile+": "+se.getMessage());
}
}
// 2. allow vm-specific override by allowing -D options in launcher
handleBooleanProperty(REPRODUCIBLE_PRNG);
handleBooleanProperty(CHECK_WEAK_KEYS);
handleBooleanProperty(DO_RSA_BLINDING);
// re-sync the 'known' properties
reproducible = new Boolean((String) props.get(REPRODUCIBLE_PRNG)).booleanValue();
checkForWeakKeys = new Boolean((String) props.get(CHECK_WEAK_KEYS)).booleanValue();
doRSABlinding = new Boolean((String) props.get(DO_RSA_BLINDING)).booleanValue();
}
private void handleBooleanProperty(final String name) {
String s = null;
try {
s = System.getProperty(name);
} catch (SecurityException x) {
if (DEBUG) debug("SecurityManager forbids reading system properties. Ignored");
}
if (s != null) {
s = s.trim().toLowerCase();
// we have to test for explicit "true" or "false". anything else may
// hide valid value set previously
if (s.equals(TRUE) || s.equals(FALSE)) {
if (DEBUG) debug("Setting "+name+" to '"+s+"'");
props.put(name, s);
} else {
if (DEBUG) debug("Invalid value for -D"+name+": "+s+". Ignored");
}
}
}
}