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43 package org.eclipse.jgit.transport;
44
45 import java.io.File;
46 import java.io.UnsupportedEncodingException;
47 import java.security.InvalidKeyException;
48 import java.security.NoSuchAlgorithmException;
49
50 import javax.crypto.Mac;
51 import javax.crypto.spec.SecretKeySpec;
52
53 import org.eclipse.jgit.internal.storage.dfs.DfsRepository;
54 import org.eclipse.jgit.lib.Repository;
55 import org.eclipse.jgit.transport.PushCertificate.NonceStatus;
56
57
58
59
60
61
62 public class HMACSHA1NonceGenerator implements NonceGenerator {
63
64 private Mac mac;
65
66
67
68
69
70 public HMACSHA1NonceGenerator(String seed) throws IllegalStateException {
71 try {
72 byte[] keyBytes = seed.getBytes("ISO-8859-1");
73 SecretKeySpec signingKey = new SecretKeySpec(keyBytes, "HmacSHA1");
74 mac = Mac.getInstance("HmacSHA1");
75 mac.init(signingKey);
76 } catch (InvalidKeyException e) {
77 throw new IllegalStateException(e);
78 } catch (NoSuchAlgorithmException e) {
79 throw new IllegalStateException(e);
80 } catch (UnsupportedEncodingException e) {
81 throw new IllegalStateException(e);
82 }
83 }
84
85 @Override
86 public synchronized String createNonce(Repository repo, long timestamp)
87 throws IllegalStateException {
88 String path;
89 if (repo instanceof DfsRepository) {
90 path = ((DfsRepository) repo).getDescription().getRepositoryName();
91 } else {
92 File directory = repo.getDirectory();
93 if (directory != null) {
94 path = directory.getPath();
95 } else {
96 throw new IllegalStateException();
97 }
98 }
99
100 String input = path + ":" + String.valueOf(timestamp);
101 byte[] rawHmac;
102 try {
103 rawHmac = mac.doFinal(input.getBytes("UTF-8"));
104 } catch (UnsupportedEncodingException e) {
105 throw new IllegalStateException(e);
106 }
107 return Long.toString(timestamp) + "-" + toHex(rawHmac);
108 }
109
110 @Override
111 public NonceStatus verify(String received, String sent,
112 Repository db, boolean allowSlop, int slop) {
113 if (received.isEmpty()) {
114 return NonceStatus.MISSING;
115 } else if (sent.isEmpty()) {
116 return NonceStatus.UNSOLICITED;
117 } else if (received.equals(sent)) {
118 return NonceStatus.OK;
119 }
120
121 if (!allowSlop) {
122 return NonceStatus.BAD;
123 }
124
125
126 int idxSent = sent.indexOf('-');
127 int idxRecv = received.indexOf('-');
128 if (idxSent == -1 || idxRecv == -1) {
129 return NonceStatus.BAD;
130 }
131
132 String signedStampStr = received.substring(0, idxRecv);
133 String advertisedStampStr = sent.substring(0, idxSent);
134 long signedStamp;
135 long advertisedStamp;
136 try {
137 signedStamp = Long.parseLong(signedStampStr);
138 advertisedStamp = Long.parseLong(advertisedStampStr);
139 } catch (IllegalArgumentException e) {
140 return NonceStatus.BAD;
141 }
142
143
144 String expect = createNonce(db, signedStamp);
145
146 if (!expect.equals(received)) {
147 return NonceStatus.BAD;
148 }
149
150 long nonceStampSlop = Math.abs(advertisedStamp - signedStamp);
151
152 if (nonceStampSlop <= slop) {
153 return NonceStatus.OK;
154 } else {
155 return NonceStatus.SLOP;
156 }
157 }
158
159 private static final String HEX = "0123456789ABCDEF";
160
161 private static String toHex(byte[] bytes) {
162 StringBuilder builder = new StringBuilder(2 * bytes.length);
163 for (byte b : bytes) {
164 builder.append(HEX.charAt((b & 0xF0) >> 4));
165 builder.append(HEX.charAt(b & 0xF));
166 }
167 return builder.toString();
168 }
169 }