org.apache.sentry.provider.file.WildcardPermission.java Source code

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Here is the source code for org.apache.sentry.provider.file.WildcardPermission.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

// copied from apache shiro

package org.apache.sentry.provider.file;

import static org.apache.sentry.provider.file.PolicyFileConstants.AUTHORIZABLE_JOINER;
import static org.apache.sentry.provider.file.PolicyFileConstants.AUTHORIZABLE_SPLITTER;

import java.io.Serializable;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.List;

import org.apache.commons.lang.text.StrSubstitutor;
import org.apache.sentry.core.AccessConstants;
import org.apache.sentry.core.Authorizable.AuthorizableType;
import org.apache.shiro.authz.Permission;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;

// XXX this class is made ugly by the fact that Action is not a Authorizable.
public class WildcardPermission implements Permission, Serializable {
    private static final Logger LOGGER = LoggerFactory.getLogger(WildcardPermission.class);
    private static final long serialVersionUID = -6785051263922740818L;

    private final ImmutableList<KeyValue> parts;

    public WildcardPermission(String wildcardString) {
        wildcardString = Strings.nullToEmpty(wildcardString).trim();
        if (wildcardString.isEmpty()) {
            throw new IllegalArgumentException("Wildcard string cannot be null or empty.");
        }
        List<KeyValue> parts = Lists.newArrayList();
        for (String authorizable : AUTHORIZABLE_SPLITTER.trimResults().split(wildcardString)) {
            if (authorizable.isEmpty()) {
                throw new IllegalArgumentException("Privilege '" + wildcardString + "' has an empty section");
            }
            parts.add(new KeyValue(authorizable));
        }
        if (parts.isEmpty()) {
            throw new AssertionError("Should never occur: " + wildcardString);
        }
        this.parts = ImmutableList.copyOf(parts);
    }

    @Override
    public boolean implies(Permission p) {
        // By default only supports comparisons with other WildcardPermissions
        if (!(p instanceof WildcardPermission)) {
            return false;
        }

        WildcardPermission wp = (WildcardPermission) p;

        List<KeyValue> otherParts = wp.parts;
        if (equals(wp)) {
            return true;
        }
        int index = 0;
        for (KeyValue otherPart : otherParts) {
            // If this permission has less parts than the other permission, everything
            // after the number of parts contained
            // in this permission is automatically implied, so return true
            if (parts.size() - 1 < index) {
                return true;
            } else {
                KeyValue part = parts.get(index);
                // are the keys even equal
                if (!part.getKey().equalsIgnoreCase(otherPart.getKey())) {
                    return false;
                }
                if (!impliesKeyValue(part, otherPart)) {
                    return false;
                }
                index++;
            }
        }
        // If this permission has more parts than
        // the other parts, only imply it if
        // all of the other parts are wildcards
        for (; index < parts.size(); index++) {
            KeyValue part = parts.get(index);
            if (!part.getValue().equals(AccessConstants.ALL)) {
                return false;
            }
        }

        return true;
    }

    private boolean impliesKeyValue(KeyValue policyPart, KeyValue requestPart) {
        Preconditions.checkState(policyPart.getKey().equalsIgnoreCase(requestPart.getKey()),
                "Please report, this method should not be called with two different keys");
        if (policyPart.getValue().equals(AccessConstants.ALL) || policyPart.equals(requestPart)) {
            return true;
        } else if (!PolicyFileConstants.PRIVILEGE_NAME.equalsIgnoreCase(policyPart.getKey())
                && AccessConstants.ALL.equalsIgnoreCase(requestPart.getValue())) {
            /* permission request is to match with any object of given type */
            return true;
        } else if (policyPart.getKey().equalsIgnoreCase(AuthorizableType.URI.name())) {
            return impliesURI(policyPart.getValue(), requestPart.getValue());
        }
        return false;
    }

    /**
     * URI is a a special case. For URI's, /a implies /a/b.
     * Therefore the test is "/a/b".startsWith("/a");
     */
    @VisibleForTesting
    protected static boolean impliesURI(String policy, String request) {
        try {
            URI policyURI = new URI(new StrSubstitutor(System.getProperties()).replace(policy));
            URI requestURI = new URI(request);
            if (policyURI.getScheme() == null || policyURI.getPath() == null) {
                LOGGER.warn("Policy URI " + policy + " is not valid. Either no scheme or no path.");
                return false;
            }
            if (requestURI.getScheme() == null || requestURI.getPath() == null) {
                LOGGER.warn("Request URI " + request + " is not valid. Either no scheme or no path.");
                return false;
            }
            // schemes are equal &&
            // request path does not contain relative parts /a/../b &&
            // request path starts with policy path &&
            // authorities (nullable) are equal
            if (policyURI.getScheme().equals(requestURI.getScheme())
                    && requestURI.getPath().equals(new URI(request).normalize().getPath())
                    && requestURI.getPath().startsWith(policyURI.getPath())
                    && Strings.nullToEmpty(policyURI.getAuthority())
                            .equals(Strings.nullToEmpty(requestURI.getAuthority()))) {
                return true;
            }
            return false;
        } catch (URISyntaxException e) {
            LOGGER.warn("Request URI " + request + " is not a URI", e);
            return false;
        }
    }

    @Override
    public String toString() {
        return AUTHORIZABLE_JOINER.join(parts);
    }

    @Override
    public boolean equals(Object o) {
        if (o instanceof WildcardPermission) {
            WildcardPermission wp = (WildcardPermission) o;
            return parts.equals(wp.parts);
        }
        return false;
    }

    @Override
    public int hashCode() {
        return parts.hashCode();
    }

}