001/**
002 *
003 * Copyright © 2014-2019 Florian Schmaus
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License");
006 * you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 *     http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.jxmpp.stringprep.simple;
018
019import java.util.Arrays;
020import java.util.Locale;
021
022import org.jxmpp.JxmppContext;
023import org.jxmpp.XmppAddressParttype;
024import org.jxmpp.stringprep.XmppStringprep;
025import org.jxmpp.stringprep.XmppStringprepException;
026import org.jxmpp.util.ArraysUtil;
027
028public final class SimpleXmppStringprep implements XmppStringprep {
029
030        private static SimpleXmppStringprep instance;
031
032        public static final String NAME = "simple";
033
034        /**
035         * Setup Simple XMPP Stringprep as implementation to use.
036         */
037        public static void setup() {
038                JxmppContext.setDefaultXmppStringprep(getInstance());
039        }
040
041        /**
042         * Get the Simple XMPP Stringprep singleton.
043         *
044         * @return the simple XMPP Stringprep singleton.
045         */
046        public static SimpleXmppStringprep getInstance() {
047                if (instance == null) {
048                        instance = new SimpleXmppStringprep();
049                }
050                return instance;
051        }
052
053        private SimpleXmppStringprep() {
054        }
055
056        /**
057         * From <a href="https://tools.ietf.org/html/rfc7622#section-3.3.1">RFC 7622 §
058         * 3.3.1</a>.
059         */
060        // @formatter:off
061        private static final char[] LOCALPART_FURTHER_EXCLUDED_CHARACTERS = new char[] {
062                '"',   // U+0022 (QUOTATION MARK) , i.e., "
063                '&',   // U+0026 (AMPERSAND), i.e., &
064                '\'',  // U+0027 (APOSTROPHE), i.e., '
065                '/',   // U+002F (SOLIDUS), i.e., /
066                ':',   // U+003A (COLON), i.e., :
067                '<',   // U+003C (LESS-THAN SIGN), i.e., <
068                '>',   // U+003E (GREATER-THAN SIGN), i.e., >
069                '@',   // U+0040 (COMMERCIAL AT), i.e., @
070        };
071        // @formatter:on
072
073        // @formatter:off
074        private static final char[] USERNAME_CASE_MAPPED_EXCLUDED_CHARACTERS = new char[] {
075                ' ',   // U+0020 (SPACE) - forbidden by PRECIS IdentifierClass.
076        };
077        // @formatter:on
078
079        private static final char[] LOCALPART_EXCLUDED_CHARACTERS;
080
081        static {
082                // Ensure that the char array is sorted as we use Arrays.binarySearch() on it.
083                Arrays.sort(LOCALPART_FURTHER_EXCLUDED_CHARACTERS);
084
085                // Combine LOCALPART_FURTHER_EXCLUDED_CHARACTERS and USERNAME_CASE_MAPPED_EXCLUDED_CHARACTERS into
086                // LOCALPART_EXCLUDED_CHARACTERS.
087                LOCALPART_EXCLUDED_CHARACTERS = ArraysUtil.concatenate(
088                                LOCALPART_FURTHER_EXCLUDED_CHARACTERS,
089                                USERNAME_CASE_MAPPED_EXCLUDED_CHARACTERS);
090                Arrays.sort(LOCALPART_EXCLUDED_CHARACTERS);
091        }
092
093        @Override
094        public String localprep(String string) throws XmppStringprepException {
095                string = simpleStringprep(string);
096                ensurePartDoesNotContain(XmppAddressParttype.localpart, string, LOCALPART_EXCLUDED_CHARACTERS);
097                return string;
098        }
099
100        private static void ensurePartDoesNotContain(XmppAddressParttype parttype, String input, char[] excludedChars)
101                        throws XmppStringprepException {
102                assert isSorted(excludedChars);
103
104                for (char c : input.toCharArray()) {
105                        int forbiddenCharPos = Arrays.binarySearch(excludedChars, c);
106                        if (forbiddenCharPos >= 0) {
107                                throw new XmppStringprepException(input, parttype.getCapitalizedName() + " must not contain '"
108                                                + LOCALPART_FURTHER_EXCLUDED_CHARACTERS[forbiddenCharPos] + "'");
109                        }
110                }
111        }
112
113        /**
114         * Ensure that the input string does not contain any of the further excluded characters of XMPP localparts.
115         *
116         * @param localpart the input string.
117         * @throws XmppStringprepException if one of the further excluded characters is found.
118         * @see <a href="https://tools.ietf.org/html/rfc7622#section-3.3.1">RFC 7622 § 3.3.1</a>
119         */
120        public static void ensureLocalpartDoesNotIncludeFurtherExcludedCharacters(String localpart)
121                        throws XmppStringprepException {
122                ensurePartDoesNotContain(XmppAddressParttype.localpart, localpart, LOCALPART_FURTHER_EXCLUDED_CHARACTERS);
123        }
124
125        @Override
126        public String domainprep(String string) throws XmppStringprepException {
127                return simpleStringprep(string);
128        }
129
130        @Override
131        public String resourceprep(String string) throws XmppStringprepException {
132                // rfc6122-bis specifies that resourceprep uses saslprep-bis OpaqueString Profile which says that
133                // "Uppercase and titlecase characters MUST NOT be mapped to their lowercase equivalents."
134
135                // TODO apply Unicode Normalization Form C (NFC) with help of java.text.Normalize
136                // but unfortunately this is API is only available on Android API 9 or higher and Smack is currently API 8
137                return string;
138        }
139
140        private static String simpleStringprep(String string) {
141                String res = string.toLowerCase(Locale.US);
142                return res;
143        }
144
145        private static boolean isSorted(char[] chars) {
146                for (int i = 1; i < chars.length; i++) {
147                        if (chars[i-1] > chars[i]) {
148                                return false;
149                        }
150                }
151                return true;
152        }
153}