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, 10 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.
#	User	Rev	Content
1	tdb	1.1	//---PACKAGE DECLARATION---
2			//package uk.org.iscream.cms.server.util;
3
4			//---IMPORTS---
5			import uk.org.iscream.cms.server.util.*;
6	tdb	1.3	import java.util.ArrayList;
7	tdb	1.7	import java.util.StringTokenizer;
8	tdb	1.1	import java.net.InetAddress;
9	tdb	1.4	import java.io.Serializable;
10	tdb	1.1
11			/**
12	tdb	1.2	* 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	tdb	1.1	*
19	tdb	1.6	* @author $Author: tdb $
20			* @version $Id: ACL.java,v 1.5 2001/12/23 01:05:35 tdb Exp $
21	tdb	1.1	*/
22	tdb	1.4	public class ACL implements Serializable {
23	tdb	1.1
24			//---FINAL ATTRIBUTES---
25
26			/**
27			* The current CVS revision of this class
28			*/
29	tdb	1.6	public static final String REVISION = "$Revision: 1.5 $";
30	tdb	1.2
31			/**
32			* static to be used when adding an ALLOW rule to the ACL.
33			*/
34	tdb	1.1	public static final boolean ALLOW = true;
35	tdb	1.2
36			/**
37			* static to be used when adding a DENY rule to the ACL.
38			*/
39	tdb	1.1	public static final boolean DENY = false;
40
41			//---STATIC METHODS---
42
43			//---CONSTRUCTORS---
44
45	tdb	1.2	/**
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	tdb	1.1	public ACL() {
51			// default to ACL.ALLOW
52			this(ACL.ALLOW);
53			}
54
55	tdb	1.2	/**
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	tdb	1.1	public ACL(boolean defaultMode) {
63			_defaultMode = defaultMode;
64			}
65
66			//---PUBLIC METHODS---
67
68	tdb	1.2	/**
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	tdb	1.1	public void add(boolean allow, String expression) {
79	tdb	1.7	// 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	tdb	1.1	}
141
142	tdb	1.2	/**
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	tdb	1.1	public boolean check(String address) {
151	tdb	1.3	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	tdb	1.1	}
156			}
157			return _defaultMode;
158			}
159
160	tdb	1.2	/**
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	tdb	1.1	public boolean check(InetAddress address) {
172	tdb	1.7	String hostname = address.getHostName();
173			String ip = address.getHostAddress();
174			short[] ipaddr = ipStringToShort(ip);
175	tdb	1.3	for(int i=0; i < _acl.size(); i++) {
176			ACLRule rule = (ACLRule) _acl.get(i);
177	tdb	1.7	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	tdb	1.1	}
184	tdb	1.7	else {
185			System.out.println("checking name rule: "+rule._expression);
186			if(StringUtils.wildcardCheck(hostname, rule._expression)) {
187			return rule._allow;
188			}
189	tdb	1.1	}
190	tdb	1.7
191	tdb	1.1	}
192			return _defaultMode;
193			}
194
195	tdb	1.2	/**
196	tdb	1.5	* Gives a String representation of this ACL.
197	tdb	1.2	*
198			* @return A String representation of this ACL.
199			*/
200	tdb	1.5	public String toString() {
201			StringBuffer acl = new StringBuffer();
202			acl.append("{");
203	tdb	1.3	for(int i=0; i < _acl.size(); i++) {
204	tdb	1.6	acl.append((ACLRule) _acl.get(i));
205	tdb	1.5	acl.append(",");
206	tdb	1.1	}
207	tdb	1.3	if(_defaultMode) {
208	tdb	1.5	acl.append("DEFAULT=ALLOW");
209	tdb	1.3	}
210			else {
211	tdb	1.5	acl.append("DEFAULT=DENY");
212	tdb	1.3	}
213	tdb	1.5	acl.append("}");
214			return acl.toString();
215	tdb	1.1	}
216
217			//---PRIVATE METHODS---
218
219	tdb	1.7	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	tdb	1.1	//---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	tdb	1.2
268			/**
269	tdb	1.3	* The ACL is stored in this ArrayList.
270	tdb	1.2	*/
271	tdb	1.3	private ArrayList _acl = new ArrayList();
272	tdb	1.2
273			/**
274			* The default mode of this ACL.
275			*/
276	tdb	1.1	private boolean _defaultMode;
277
278			//---STATIC ATTRIBUTES---
279
280			//---INNER CLASSES---
281
282	tdb	1.2	/**
283			* Wrapper class for an ACL rule.
284			*/
285	tdb	1.4	private class ACLRule implements Serializable {
286	tdb	1.1
287	tdb	1.2	/**
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	tdb	1.7	* @param iprule whether this is an IP rule
293	tdb	1.2	*/
294	tdb	1.7	private ACLRule(boolean allow, String expression, short[] ipaddr, boolean iprule) {
295	tdb	1.1	_allow = allow;
296			_expression = expression;
297	tdb	1.7	_ipaddr = ipaddr;
298			_iprule = iprule;
299	tdb	1.6	}
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	tdb	1.1	}
314
315	tdb	1.2	/**
316			* Whether this is an ALLOW or DENY rule.
317			*/
318	tdb	1.1	private boolean _allow;
319	tdb	1.2
320			/**
321			* What this rule matches.
322			*/
323	tdb	1.1	private String _expression;
324	tdb	1.7
325			private short[] _ipaddr;
326
327			/**
328			* Whether this is an IP rule.
329			*/
330			private boolean _iprule;
331	tdb	1.1
332			}
333
334			}