server/ACL/ACL.java

//---PACKAGE DECLARATION---
//package uk.org.iscream.cms.server.util;

//---IMPORTS---
import uk.org.iscream.cms.server.util.*;
import java.util.ArrayList;
import java.util.StringTokenizer;
import java.net.InetAddress;
import java.io.Serializable;

/**
 * Access Control List for use primarily
 * with the ACLServerSocket. It could, however
 * have other uses as it has a fairly generic
 * behaviour. Rules are added using the add
 * method, and then checks can be made using
 * the relevant check method.
 *
 * @author  $Author: tdb $
 * @version $Id: ACL.java,v 1.5 2001/12/23 01:05:35 tdb Exp $
 */
public class ACL implements Serializable {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public static final String REVISION = "$Revision: 1.5 $";
    
    /**
     * static to be used when adding an ALLOW rule to the ACL.
     */
    public static final boolean ALLOW = true;
    
    /**
     * static to be used when adding a DENY rule to the ACL.
     */
    public static final boolean DENY = false;

//---STATIC METHODS---

//---CONSTRUCTORS---

    /**
     * Construct a new Access Control List. The default
     * mode is to ALLOW anything that isn't explicitly
     * blocked by a rule.
     */
    public ACL() {
        // default to ACL.ALLOW
        this(ACL.ALLOW);
    }
    
    /**
     * Construct a new Access Control List with a given
     * default mode. This mode specifies what should
     * happen if a check does not match any rules.
     *
     * @param defaultMode the default mode for non-matched checks
     */
    public ACL(boolean defaultMode) {
        _defaultMode = defaultMode;
    }

//---PUBLIC METHODS---

    /**
     * Add a new rule to the ACL immediately after the
     * previous rule. The rule can either be an ACL.ALLOW
     * rule, or an ACL.DENY rule. The expression can
     * contain a wildcard (a * only). Rules can only be
     * added to the end of the list.
     *
     * param allow whether this is an ALLOW or DENY rule
     * param expression what this rule matches using wildcards
     */
    public void add(boolean allow, String expression) {
        // default to expecting it to be an IP
        // we will try to disprove this :)
        boolean ip = true;
        short[] ipaddr = {-1, -1, -1, -1};
        int i = 0;
        String s = "";
        // tokenize the expression on fullstops, so we can break
        // up the quads of an IP (if it's an IP!)
        StringTokenizer st = new StringTokenizer(expression, ".");
        while(st.hasMoreTokens() && i++ < 4) {
            s = st.nextToken();
            // if it's a wildcard, we'll skip to the next one
            // as no more checks are required
            if(s.equals("*")) {
                continue;
            }
            // attempt to parse it into a short
            try {
                short n = Short.parseShort(s);
                // if it's an int but outside of the
                // valid range, it can't be an IP
                if(n < 0 || n > 255) {
                    ip = false;
                    // give up checking further
                    break;
                }
                ipaddr[i-1] = n;
            }
            // if it didn't parse as an int it can't be an IP
            catch (NumberFormatException e) {
                ip = false;
                // give up checking further
                break;
            }
        }
        // we've done 4 parts, so if there's any
        // more this can't be an IP
        if(st.hasMoreTokens()) {
            ip = false;
        }
        // if we've done less than 4, see if the last one
        // was a wildcard - if it isn't then it's not an IP
        //   -- this allows 129.12.*
        if(i < 4 && !s.equals("*")) {
            ip = false;
        }
        // if we had one or less entries it can't be an IP
        //   -- this disallows * matching as an IP due
        //      to the rule above
        if(i <= 1) {
            ip = false;
        }
        // finally print out what we've found.
        System.out.println("IP("+ip+"): "+expression);
        if(ip) {
            for(int j=0; j < ipaddr.length; j++) {
                System.out.print(ipaddr[j] + " ");
            }
            System.out.println();
        }
        _acl.add(new ACLRule(allow, expression, ipaddr, ip));
    }
    
    /**
     * Check to see if a string is permitted by the
     * ACL. Useful for testing, and non-Socket uses
     * of this class.
     *
     * @param address the string to check
     * @return whether the address was permitted by the ACL
     */
    public boolean check(String address) {
        for(int i=0; i < _acl.size(); i++) {
            ACLRule rule = (ACLRule) _acl.get(i);
            if(StringUtils.wildcardCheck(address, rule._expression)) {
                return rule._allow;
            }
        }
        return _defaultMode;
    }
    
    /**
     * Check to see if an InetAddress is permitted
     * by the ACL. Perfect for Socket uses of this
     * class. It should be made clear that this will
     * check both the hostname AND IP address against
     * each rule in turn. The hostname will always be
     * checked BEFORE the IP address.
     *
     * @param address the InetAddress to check
     * @return whether the InetAddress was permitted by the ACL
     */
    public boolean check(InetAddress address) {
        String hostname = address.getHostName();
        String ip = address.getHostAddress();
        short[] ipaddr = ipStringToShort(ip);
        for(int i=0; i < _acl.size(); i++) {
            ACLRule rule = (ACLRule) _acl.get(i);
            if(rule._iprule) {
                System.out.println("checking ip rule "+rule._expression);
                //if(StringUtils.wildcardCheck(ip, rule._expression)) {
                if(compareShorts(ipaddr, rule._ipaddr)) {
                    return rule._allow;
                }
            }
            else {
                System.out.println("checking name rule: "+rule._expression);
                if(StringUtils.wildcardCheck(hostname, rule._expression)) {
                    return rule._allow;
                }
            }
            
        }
        return _defaultMode;
    }
    
    /**
     * Gives a String representation of this ACL.
     *
     * @return A String representation of this ACL.
     */
    public String toString() {
        StringBuffer acl = new StringBuffer();
        acl.append("{");
        for(int i=0; i < _acl.size(); i++) {
            acl.append((ACLRule) _acl.get(i));
            acl.append(",");
        }
        if(_defaultMode) {
            acl.append("DEFAULT=ALLOW");
        }
        else {
            acl.append("DEFAULT=DENY");
        }
        acl.append("}");
        return acl.toString();
    }

//---PRIVATE METHODS---

    private short[] ipStringToShort(String ip) {
        short[] ipaddr = {-1, -1, -1, -1};
        StringTokenizer st = new StringTokenizer(ip, ".");
        for(int i=0; i < 4 && st.hasMoreTokens(); i++) {
            try {
                ipaddr[i] = Short.parseShort(st.nextToken());
            }
            catch(NumberFormatException e) {
                // do nothing?
            }
        }
        return ipaddr;
    }
    
    private boolean compareShorts(short[] first, short[] second) {
        if(first.length != second.length) {
            System.out.println("not equal length");
            return false;
        }
        for(int i=0; i < first.length; i++) {
            // -- might want to consider specify which is the wildcard one?
            System.out.println(i + ":" + first[i] + "," + second[i]);
            if(first[i] == -1 || second[i] == -1) {
                continue;
            }
            if(first[i] != second[i]) {
                System.out.println("not equal");
                return false;
            }
        }
        System.out.println("equal");
        return true;
    }

//---ACCESSOR/MUTATOR METHODS---

//---ATTRIBUTES---

    /**
     * This is the friendly identifier of the
     * component this class is running in.
     * eg, a Filter may be called "filter1",
     * If this class does not have an owning
     * component,  a name from the configuration
     * can be placed here.  This name could also
     * be changed to null for utility classes.
     */
    private String _name = null;
    
    /**
     * The ACL is stored in this ArrayList.
     */
    private ArrayList _acl = new ArrayList();
    
    /**
     * The default mode of this ACL.
     */
    private boolean _defaultMode;

//---STATIC ATTRIBUTES---

//---INNER CLASSES---

    /**
     * Wrapper class for an ACL rule.
     */
    private class ACLRule implements Serializable {
        
        /**
         * Construct an ACL rule.
         *
         * @param allow whether this is an ALLOW or DENY rule
         * @param expression what this rule matches
         * @param iprule whether this is an IP rule
         */
        private ACLRule(boolean allow, String expression, short[] ipaddr, boolean iprule) {
            _allow = allow;
            _expression = expression;
            _ipaddr = ipaddr;
            _iprule = iprule;
        }
        
        /**
         * Returns a String representation of this rule.
         *
         * @return A String representation of this rule.
         */
        public String toString() {
            if(_allow) {
                return _expression + "=ALLOW";
            }
            else {
                return _expression + "=DENY";
            }
        }
        
        /**
         * Whether this is an ALLOW or DENY rule.
         */
        private boolean _allow;
        
        /**
         * What this rule matches.
         */
        private String _expression;
        
        private short[] _ipaddr;
        
        /**
         * Whether this is an IP rule.
         */
        private boolean _iprule;
        
    }

}
Revision:	1.7
Committed:	Mon Dec 31 01:49:13 2001 UTC (22 years, 4 months ago) by tdb
Branch:	MAIN
Changes since 1.6:	+122 -6 lines
Log Message:	Some significant internal changes. It should be noted that this code is still in the debugging stage, and thus contains lots of println's :-) The most obvious change is that when adding a rule we try to determine if it's and IP address given as the expression. If it is, we store this in a short[] in the ACLRule inner class. Then when performing a check we look to see if it's an IP address rule, and then do a special check for IP addresses - which is much more efficient than comparing two strings. We have also halved the checks done by only comparing a rule to either the name or IP, rather than both.
#	Content
1	//---PACKAGE DECLARATION---
2	//package uk.org.iscream.cms.server.util;
3
4	//---IMPORTS---
5	import uk.org.iscream.cms.server.util.*;
6	import java.util.ArrayList;
7	import java.util.StringTokenizer;
8	import java.net.InetAddress;
9	import java.io.Serializable;
10
11	/**
12	* Access Control List for use primarily
13	* with the ACLServerSocket. It could, however
14	* have other uses as it has a fairly generic
15	* behaviour. Rules are added using the add
16	* method, and then checks can be made using
17	* the relevant check method.
18	*
19	* @author $Author: tdb $
20	* @version $Id: ACL.java,v 1.5 2001/12/23 01:05:35 tdb Exp $
21	*/
22	public class ACL implements Serializable {
23
24	//---FINAL ATTRIBUTES---
25
26	/**
27	* The current CVS revision of this class
28	*/
29	public static final String REVISION = "$Revision: 1.5 $";
30
31	/**
32	* static to be used when adding an ALLOW rule to the ACL.
33	*/
34	public static final boolean ALLOW = true;
35
36	/**
37	* static to be used when adding a DENY rule to the ACL.
38	*/
39	public static final boolean DENY = false;
40
41	//---STATIC METHODS---
42
43	//---CONSTRUCTORS---
44
45	/**
46	* Construct a new Access Control List. The default
47	* mode is to ALLOW anything that isn't explicitly
48	* blocked by a rule.
49	*/
50	public ACL() {
51	// default to ACL.ALLOW
52	this(ACL.ALLOW);
53	}
54
55	/**
56	* Construct a new Access Control List with a given
57	* default mode. This mode specifies what should
58	* happen if a check does not match any rules.
59	*
60	* @param defaultMode the default mode for non-matched checks
61	*/
62	public ACL(boolean defaultMode) {
63	_defaultMode = defaultMode;
64	}
65
66	//---PUBLIC METHODS---
67
68	/**
69	* Add a new rule to the ACL immediately after the
70	* previous rule. The rule can either be an ACL.ALLOW
71	* rule, or an ACL.DENY rule. The expression can
72	* contain a wildcard (a * only). Rules can only be
73	* added to the end of the list.
74	*
75	* param allow whether this is an ALLOW or DENY rule
76	* param expression what this rule matches using wildcards
77	*/
78	public void add(boolean allow, String expression) {
79	// default to expecting it to be an IP
80	// we will try to disprove this :)
81	boolean ip = true;
82	short[] ipaddr = {-1, -1, -1, -1};
83	int i = 0;
84	String s = "";
85	// tokenize the expression on fullstops, so we can break
86	// up the quads of an IP (if it's an IP!)
87	StringTokenizer st = new StringTokenizer(expression, ".");
88	while(st.hasMoreTokens() && i++ < 4) {
89	s = st.nextToken();
90	// if it's a wildcard, we'll skip to the next one
91	// as no more checks are required
92	if(s.equals("*")) {
93	continue;
94	}
95	// attempt to parse it into a short
96	try {
97	short n = Short.parseShort(s);
98	// if it's an int but outside of the
99	// valid range, it can't be an IP
100	if(n < 0 \|\| n > 255) {
101	ip = false;
102	// give up checking further
103	break;
104	}
105	ipaddr[i-1] = n;
106	}
107	// if it didn't parse as an int it can't be an IP
108	catch (NumberFormatException e) {
109	ip = false;
110	// give up checking further
111	break;
112	}
113	}
114	// we've done 4 parts, so if there's any
115	// more this can't be an IP
116	if(st.hasMoreTokens()) {
117	ip = false;
118	}
119	// if we've done less than 4, see if the last one
120	// was a wildcard - if it isn't then it's not an IP
121	// -- this allows 129.12.*
122	if(i < 4 && !s.equals("*")) {
123	ip = false;
124	}
125	// if we had one or less entries it can't be an IP
126	// -- this disallows * matching as an IP due
127	// to the rule above
128	if(i <= 1) {
129	ip = false;
130	}
131	// finally print out what we've found.
132	System.out.println("IP("+ip+"): "+expression);
133	if(ip) {
134	for(int j=0; j < ipaddr.length; j++) {
135	System.out.print(ipaddr[j] + " ");
136	}
137	System.out.println();
138	}
139	_acl.add(new ACLRule(allow, expression, ipaddr, ip));
140	}
141
142	/**
143	* Check to see if a string is permitted by the
144	* ACL. Useful for testing, and non-Socket uses
145	* of this class.
146	*
147	* @param address the string to check
148	* @return whether the address was permitted by the ACL
149	*/
150	public boolean check(String address) {
151	for(int i=0; i < _acl.size(); i++) {
152	ACLRule rule = (ACLRule) _acl.get(i);
153	if(StringUtils.wildcardCheck(address, rule._expression)) {
154	return rule._allow;
155	}
156	}
157	return _defaultMode;
158	}
159
160	/**
161	* Check to see if an InetAddress is permitted
162	* by the ACL. Perfect for Socket uses of this
163	* class. It should be made clear that this will
164	* check both the hostname AND IP address against
165	* each rule in turn. The hostname will always be
166	* checked BEFORE the IP address.
167	*
168	* @param address the InetAddress to check
169	* @return whether the InetAddress was permitted by the ACL
170	*/
171	public boolean check(InetAddress address) {
172	String hostname = address.getHostName();
173	String ip = address.getHostAddress();
174	short[] ipaddr = ipStringToShort(ip);
175	for(int i=0; i < _acl.size(); i++) {
176	ACLRule rule = (ACLRule) _acl.get(i);
177	if(rule._iprule) {
178	System.out.println("checking ip rule "+rule._expression);
179	//if(StringUtils.wildcardCheck(ip, rule._expression)) {
180	if(compareShorts(ipaddr, rule._ipaddr)) {
181	return rule._allow;
182	}
183	}
184	else {
185	System.out.println("checking name rule: "+rule._expression);
186	if(StringUtils.wildcardCheck(hostname, rule._expression)) {
187	return rule._allow;
188	}
189	}
190
191	}
192	return _defaultMode;
193	}
194
195	/**
196	* Gives a String representation of this ACL.
197	*
198	* @return A String representation of this ACL.
199	*/
200	public String toString() {
201	StringBuffer acl = new StringBuffer();
202	acl.append("{");
203	for(int i=0; i < _acl.size(); i++) {
204	acl.append((ACLRule) _acl.get(i));
205	acl.append(",");
206	}
207	if(_defaultMode) {
208	acl.append("DEFAULT=ALLOW");
209	}
210	else {
211	acl.append("DEFAULT=DENY");
212	}
213	acl.append("}");
214	return acl.toString();
215	}
216
217	//---PRIVATE METHODS---
218
219	private short[] ipStringToShort(String ip) {
220	short[] ipaddr = {-1, -1, -1, -1};
221	StringTokenizer st = new StringTokenizer(ip, ".");
222	for(int i=0; i < 4 && st.hasMoreTokens(); i++) {
223	try {
224	ipaddr[i] = Short.parseShort(st.nextToken());
225	}
226	catch(NumberFormatException e) {
227	// do nothing?
228	}
229	}
230	return ipaddr;
231	}
232
233	private boolean compareShorts(short[] first, short[] second) {
234	if(first.length != second.length) {
235	System.out.println("not equal length");
236	return false;
237	}
238	for(int i=0; i < first.length; i++) {
239	// -- might want to consider specify which is the wildcard one?
240	System.out.println(i + ":" + first[i] + "," + second[i]);
241	if(first[i] == -1 \|\| second[i] == -1) {
242	continue;
243	}
244	if(first[i] != second[i]) {
245	System.out.println("not equal");
246	return false;
247	}
248	}
249	System.out.println("equal");
250	return true;
251	}
252
253	//---ACCESSOR/MUTATOR METHODS---
254
255	//---ATTRIBUTES---
256
257	/**
258	* This is the friendly identifier of the
259	* component this class is running in.
260	* eg, a Filter may be called "filter1",
261	* If this class does not have an owning
262	* component, a name from the configuration
263	* can be placed here. This name could also
264	* be changed to null for utility classes.
265	*/
266	private String _name = null;
267
268	/**
269	* The ACL is stored in this ArrayList.
270	*/
271	private ArrayList _acl = new ArrayList();
272
273	/**
274	* The default mode of this ACL.
275	*/
276	private boolean _defaultMode;
277
278	//---STATIC ATTRIBUTES---
279
280	//---INNER CLASSES---
281
282	/**
283	* Wrapper class for an ACL rule.
284	*/
285	private class ACLRule implements Serializable {
286
287	/**
288	* Construct an ACL rule.
289	*
290	* @param allow whether this is an ALLOW or DENY rule
291	* @param expression what this rule matches
292	* @param iprule whether this is an IP rule
293	*/
294	private ACLRule(boolean allow, String expression, short[] ipaddr, boolean iprule) {
295	_allow = allow;
296	_expression = expression;
297	_ipaddr = ipaddr;
298	_iprule = iprule;
299	}
300
301	/**
302	* Returns a String representation of this rule.
303	*
304	* @return A String representation of this rule.
305	*/
306	public String toString() {
307	if(_allow) {
308	return _expression + "=ALLOW";
309	}
310	else {
311	return _expression + "=DENY";
312	}
313	}
314
315	/**
316	* Whether this is an ALLOW or DENY rule.
317	*/
318	private boolean _allow;
319
320	/**
321	* What this rule matches.
322	*/
323	private String _expression;
324
325	private short[] _ipaddr;
326
327	/**
328	* Whether this is an IP rule.
329	*/
330	private boolean _iprule;
331
332	}
333
334	}