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 1.8 2001/12/31 02:57:00 tdb Exp $
 */
public class ACL implements Serializable {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public static final String REVISION = "$Revision: 1.8 $";
    
    /**
     * 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;
        }
        // add the rule to our array
        _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. A rule will either be for a name, or
     * an IP address (this is determined in the add
     * method), and the appropriate comparison will
     * be performed.
     *
     * @param address the InetAddress to check
     * @return whether the InetAddress was permitted by the ACL
     */
    public boolean check(InetAddress address) {
        // gather the details first
        String hostname = address.getHostName();
        String ip = address.getHostAddress();
        short[] ipaddr = ipStringToShort(ip);
        // check each rule against this InetAddress
        for(int i=0; i < _acl.size(); i++) {
            ACLRule rule = (ACLRule) _acl.get(i);
            if(rule._iprule) {
                // if this is an IP rule do a short comparison
                if(compareShorts(ipaddr, rule._ipaddr)) {
                    return rule._allow;
                }
            }
            else {
                // if not do a full blown String comparsion
                if(StringUtils.wildcardCheck(hostname, rule._expression)) {
                    return rule._allow;
                }
            }
            
        }
        // if we haven't matched a rule, return the default
        return _defaultMode;
    }
    
    /**
     * Gives a String representation of this ACL.
     *
     * @return A String representation of this ACL.
     */
    public String toString() {
        StringBuffer acl = new StringBuffer();
        // put in the i-scream toString code
        acl.append(FormatName.getName(_name, getClass().getName(), REVISION));
        acl.append("{");
        // put the value of each Rule in the result
        for(int i=0; i < _acl.size(); i++) {
            acl.append((ACLRule) _acl.get(i));
            acl.append(",");
        }
        // put the default mode in the result
        if(_defaultMode) {
            acl.append("DEFAULT=ALLOW");
        }
        else {
            acl.append("DEFAULT=DENY");
        }
        acl.append("}");
        return acl.toString();
    }

//---PRIVATE METHODS---

    /**
     * Converts an IP address in String format into
     * a short array of length 4. Any wildcards, *,
     * found in the IP address are represented by
     * a -1.
     * 
     * @param ip The IP address in String format
     * @return The IP address in a short[]
     */
    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?
                // we just want to leave it as -1
                // -- actually, maybe we want to do more checks in here?
                //    although in this code context it'll probably be ok,
                //    it might be worth verifying wildcards and that the
                //    number is in range...
            }
        }
        return ipaddr;
    }
    
    /**
     * Compares two short arrays. The array can contain a -1, which
     * will always match any value -- it's a wildcard. They must be
     * the same length to match. At the moment the order of the
     * parameters does not matter.
     *
     * @param first The first array to compare
     * @param second The second array to compare
     * @result the result of the comparison
     */
    private boolean compareShorts(short[] first, short[] second) {
        if(first.length != second.length) {
            return false;
        }
        for(int i=0; i < first.length; i++) {
            // -- might want to consider specify which is the wildcard one?
            if(first[i] == -1 || second[i] == -1) {
                continue;
            }
            if(first[i] != second[i]) {
                return false;
            }
        }
        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 ipaddr the IP address wildcard this rule matches if it's an IP rule
         * @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;
        
        /**
         * The IP wildcard, only valid if this
         * is an IP rule.
         */
        private short[] _ipaddr;
        
        /**
         * Whether this is an IP rule.
         */
        private boolean _iprule;
        
    }

}
Revision:	1.10
Committed:	Mon Dec 31 19:25:39 2001 UTC (22 years, 10 months ago) by tdb
Branch:	MAIN
Changes since 1.9:	+1 -0 lines
Log Message:	Opps. Lost a bracket. Right, it's time to go out for New Year :-) In fact, this commit log will be mailed at about 1 minute into 2002 ;-)
#	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	tdb	1.9	* @version $Id: ACL.java,v 1.8 2001/12/31 02:57:00 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	1.9	public static final String REVISION = "$Revision: 1.8 $";
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	tdb	1.9	// add the rule to our array
132	tdb	1.7	_acl.add(new ACLRule(allow, expression, ipaddr, ip));
133	tdb	1.1	}
134
135	tdb	1.2	/**
136			* Check to see if a string is permitted by the
137			* ACL. Useful for testing, and non-Socket uses
138			* of this class.
139			*
140			* @param address the string to check
141			* @return whether the address was permitted by the ACL
142			*/
143	tdb	1.1	public boolean check(String address) {
144	tdb	1.3	for(int i=0; i < _acl.size(); i++) {
145			ACLRule rule = (ACLRule) _acl.get(i);
146			if(StringUtils.wildcardCheck(address, rule._expression)) {
147			return rule._allow;
148	tdb	1.1	}
149			}
150			return _defaultMode;
151			}
152
153	tdb	1.2	/**
154			* Check to see if an InetAddress is permitted
155			* by the ACL. Perfect for Socket uses of this
156	tdb	1.9	* class. A rule will either be for a name, or
157			* an IP address (this is determined in the add
158			* method), and the appropriate comparison will
159			* be performed.
160	tdb	1.2	*
161			* @param address the InetAddress to check
162			* @return whether the InetAddress was permitted by the ACL
163			*/
164	tdb	1.1	public boolean check(InetAddress address) {
165	tdb	1.9	// gather the details first
166	tdb	1.7	String hostname = address.getHostName();
167			String ip = address.getHostAddress();
168			short[] ipaddr = ipStringToShort(ip);
169	tdb	1.9	// check each rule against this InetAddress
170	tdb	1.3	for(int i=0; i < _acl.size(); i++) {
171			ACLRule rule = (ACLRule) _acl.get(i);
172	tdb	1.7	if(rule._iprule) {
173	tdb	1.9	// if this is an IP rule do a short comparison
174	tdb	1.7	if(compareShorts(ipaddr, rule._ipaddr)) {
175			return rule._allow;
176			}
177	tdb	1.1	}
178	tdb	1.7	else {
179	tdb	1.9	// if not do a full blown String comparsion
180	tdb	1.7	if(StringUtils.wildcardCheck(hostname, rule._expression)) {
181			return rule._allow;
182			}
183	tdb	1.1	}
184	tdb	1.7
185	tdb	1.1	}
186	tdb	1.9	// if we haven't matched a rule, return the default
187	tdb	1.1	return _defaultMode;
188			}
189
190	tdb	1.2	/**
191	tdb	1.5	* Gives a String representation of this ACL.
192	tdb	1.2	*
193			* @return A String representation of this ACL.
194			*/
195	tdb	1.5	public String toString() {
196			StringBuffer acl = new StringBuffer();
197	tdb	1.9	// put in the i-scream toString code
198	tdb	1.8	acl.append(FormatName.getName(_name, getClass().getName(), REVISION));
199	tdb	1.5	acl.append("{");
200	tdb	1.9	// put the value of each Rule in the result
201	tdb	1.3	for(int i=0; i < _acl.size(); i++) {
202	tdb	1.6	acl.append((ACLRule) _acl.get(i));
203	tdb	1.5	acl.append(",");
204	tdb	1.1	}
205	tdb	1.9	// put the default mode in the result
206	tdb	1.3	if(_defaultMode) {
207	tdb	1.5	acl.append("DEFAULT=ALLOW");
208	tdb	1.3	}
209			else {
210	tdb	1.5	acl.append("DEFAULT=DENY");
211	tdb	1.3	}
212	tdb	1.5	acl.append("}");
213			return acl.toString();
214	tdb	1.1	}
215
216			//---PRIVATE METHODS---
217
218	tdb	1.9	/**
219			* Converts an IP address in String format into
220			* a short array of length 4. Any wildcards, *,
221			* found in the IP address are represented by
222			* a -1.
223			*
224			* @param ip The IP address in String format
225			* @return The IP address in a short[]
226			*/
227	tdb	1.7	private short[] ipStringToShort(String ip) {
228			short[] ipaddr = {-1, -1, -1, -1};
229			StringTokenizer st = new StringTokenizer(ip, ".");
230			for(int i=0; i < 4 && st.hasMoreTokens(); i++) {
231			try {
232			ipaddr[i] = Short.parseShort(st.nextToken());
233			}
234			catch(NumberFormatException e) {
235			// do nothing?
236	tdb	1.9	// we just want to leave it as -1
237			// -- actually, maybe we want to do more checks in here?
238			// although in this code context it'll probably be ok,
239			// it might be worth verifying wildcards and that the
240			// number is in range...
241	tdb	1.7	}
242			}
243			return ipaddr;
244			}
245
246	tdb	1.9	/**
247			* Compares two short arrays. The array can contain a -1, which
248			* will always match any value -- it's a wildcard. They must be
249			* the same length to match. At the moment the order of the
250			* parameters does not matter.
251			*
252			* @param first The first array to compare
253			* @param second The second array to compare
254			* @result the result of the comparison
255			*/
256	tdb	1.7	private boolean compareShorts(short[] first, short[] second) {
257			if(first.length != second.length) {
258			return false;
259			}
260			for(int i=0; i < first.length; i++) {
261			// -- might want to consider specify which is the wildcard one?
262			if(first[i] == -1 \|\| second[i] == -1) {
263			continue;
264			}
265			if(first[i] != second[i]) {
266			return false;
267			}
268	tdb	1.10	}
269	tdb	1.7	return true;
270			}
271
272	tdb	1.1	//---ACCESSOR/MUTATOR METHODS---
273
274			//---ATTRIBUTES---
275
276			/**
277			* This is the friendly identifier of the
278			* component this class is running in.
279			* eg, a Filter may be called "filter1",
280			* If this class does not have an owning
281			* component, a name from the configuration
282			* can be placed here. This name could also
283			* be changed to null for utility classes.
284			*/
285			private String _name = null;
286	tdb	1.2
287			/**
288	tdb	1.3	* The ACL is stored in this ArrayList.
289	tdb	1.2	*/
290	tdb	1.3	private ArrayList _acl = new ArrayList();
291	tdb	1.2
292			/**
293			* The default mode of this ACL.
294			*/
295	tdb	1.1	private boolean _defaultMode;
296
297			//---STATIC ATTRIBUTES---
298
299			//---INNER CLASSES---
300
301	tdb	1.2	/**
302			* Wrapper class for an ACL rule.
303			*/
304	tdb	1.4	private class ACLRule implements Serializable {
305	tdb	1.1
306	tdb	1.2	/**
307			* Construct an ACL rule.
308			*
309			* @param allow whether this is an ALLOW or DENY rule
310			* @param expression what this rule matches
311	tdb	1.9	* @param ipaddr the IP address wildcard this rule matches if it's an IP rule
312	tdb	1.7	* @param iprule whether this is an IP rule
313	tdb	1.2	*/
314	tdb	1.7	private ACLRule(boolean allow, String expression, short[] ipaddr, boolean iprule) {
315	tdb	1.1	_allow = allow;
316			_expression = expression;
317	tdb	1.7	_ipaddr = ipaddr;
318			_iprule = iprule;
319	tdb	1.6	}
320
321			/**
322			* Returns a String representation of this rule.
323			*
324			* @return A String representation of this rule.
325			*/
326			public String toString() {
327			if(_allow) {
328			return _expression + "=ALLOW";
329			}
330			else {
331			return _expression + "=DENY";
332			}
333	tdb	1.1	}
334
335	tdb	1.2	/**
336			* Whether this is an ALLOW or DENY rule.
337			*/
338	tdb	1.1	private boolean _allow;
339	tdb	1.2
340			/**
341			* What this rule matches.
342			*/
343	tdb	1.1	private String _expression;
344	tdb	1.7
345	tdb	1.9	/**
346			* The IP wildcard, only valid if this
347			* is an IP rule.
348			*/
349	tdb	1.7	private short[] _ipaddr;
350
351			/**
352			* Whether this is an IP rule.
353			*/
354			private boolean _iprule;
355	tdb	1.1
356			}
357
358			}