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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
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package org.jcp.xml.dsig.internal.dom;

import java.net.URI;
import java.net.URISyntaxException;
import java.security.AccessController;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.Security;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Locale;
import java.util.Map;
import java.util.Set;

The secure validation policy as specified by the
jdk.xml.dsig.secureValidationPolicy security property.
/**
 * The secure validation policy as specified by the
 * jdk.xml.dsig.secureValidationPolicy security property.
 */
public final class Policy {

    // all restrictions are initialized to be unconstrained
    private static Set<URI> disallowedAlgs = new HashSet<URI>();
    private static int maxTrans = Integer.MAX_VALUE;
    private static int maxRefs = Integer.MAX_VALUE;
    private static Set<String> disallowedRefUriSchemes = new HashSet<String>();
    private static Map<String, Integer> minKeyMap = new HashMap<String, Integer>();
    private static boolean noDuplicateIds = false;
    private static boolean noRMLoops = false;

    static {
        try {
            initialize();
        } catch (Exception e) {
            throw new SecurityException(
                "Cannot initialize the secure validation policy", e);
        }
    }

    private Policy() {}

    private static void initialize() {
	String prop = AccessController.doPrivileged(new PrivilegedAction<String>() {
                public String run() {
                    return Security.getProperty("jdk.xml.dsig.secureValidationPolicy");
                }
            });

        if (prop == null || prop.isEmpty()) {
            // no policy specified, so don't enforce any restrictions
            return;
        }
        String[] entries = prop.split(",");
        for (String entry : entries) {
            String[] tokens = entry.split("\\s");
            String type = tokens[0];
            if (type.equals("disallowAlg")) {
                if (tokens.length != 2) {
                    error(entry);
                }
                disallowedAlgs.add(URI.create(tokens[1]));
            } else if (type.equals("maxTransforms")) {
                if (tokens.length != 2) {
                    error(entry);
                }
                maxTrans = Integer.parseInt(tokens[1]);
                if (maxTrans < 0) {
                    throw new NumberFormatException(String.format("Illegal leading minus sign " +
                                                                  "on unsigned string %s.", tokens[1]));
                }
            } else if (type.equals("maxReferences")) {
                if (tokens.length != 2) {
                    error(entry);
                }
                maxRefs = Integer.parseInt(tokens[1]);
                if (maxRefs < 0) {
                    throw new NumberFormatException(String.format("Illegal leading minus sign " +
                                                                  "on unsigned string %s.", tokens[1]));
                }
            } else if (type.equals("disallowReferenceUriSchemes")) {
                if (tokens.length == 1) {
                    error(entry);
                }
                for (int i = 1; i < tokens.length; i++) {
                    String scheme = tokens[i];
                    disallowedRefUriSchemes.add(
                        scheme.toLowerCase(Locale.ROOT));
                }
            } else if (type.equals("minKeySize")) {
                if (tokens.length != 3) {
                    error(entry);
                }
                Integer v = Integer.parseInt(tokens[2]);
                if (v < 0) {
                    throw new NumberFormatException(String.format("Illegal leading minus sign " +
                                                                  "on unsigned string %s.", tokens[2]));
                }
                minKeyMap.put(tokens[1], v);
            } else if (type.equals("noDuplicateIds")) {
                if (tokens.length != 1) {
                    error(entry);
                }
                noDuplicateIds = true;
            } else if (type.equals("noRetrievalMethodLoops")) {
                if (tokens.length != 1) {
                    error(entry);
                }
                noRMLoops = true;
            } else {
                error(entry);
            }
        }
    }

    public static boolean restrictAlg(String alg) {
        try {
            URI uri = new URI(alg);
            return disallowedAlgs.contains(uri);
        } catch (URISyntaxException use) {
            return false;
        }
    }

    public static boolean restrictNumTransforms(int numTrans) {
        return (numTrans > maxTrans);
    }

    public static boolean restrictNumReferences(int numRefs) {
        return (numRefs > maxRefs);
    }

    public static boolean restrictReferenceUriScheme(String uri) {
        if (uri != null) {
            String scheme = java.net.URI.create(uri).getScheme();
            if (scheme != null) {
                return disallowedRefUriSchemes.contains(
                    scheme.toLowerCase(Locale.ROOT));
            }
        }
        return false;
    }

    public static boolean restrictKey(String type, int size) {
        return (size < getMinKeyOrDefault(type, 0));
    }

    private static Integer getMinKeyOrDefault(Object key, Integer defaultValue) {
	Integer v;
	return (((v = minKeyMap.get(key)) != null) || minKeyMap.containsKey(key))
            ? v
	    : defaultValue;
    }


    public static boolean restrictDuplicateIds() {
        return noDuplicateIds;
    }

    public static boolean restrictRetrievalMethodLoops() {
        return noRMLoops;
    }

    public static Set<URI> disabledAlgs() {
        return Collections.<URI>unmodifiableSet(disallowedAlgs);
    }

    public static int maxTransforms() {
        return maxTrans;
    }

    public static int maxReferences() {
        return maxRefs;
    }

    public static Set<String> disabledReferenceUriSchemes() {
        return Collections.<String>unmodifiableSet(disallowedRefUriSchemes);
    }

    public static int minKeySize(String type) {
        return getMinKeyOrDefault(type, 0);
    }

    private static void error(String entry) {
        throw new IllegalArgumentException(
            "Invalid jdk.xml.dsig.secureValidationPolicy entry: " + entry);
    }
}