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comparison src/com/trilead/ssh2/crypto/PEMDecoder.java @ 0:0ce5cc452d02

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initial version
author Carl Byington <carl@five-ten-sg.com>
date Thu, 22 May 2014 10:41:19 -0700
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1
2 package com.trilead.ssh2.crypto;
3
4 import java.io.BufferedReader;
5 import java.io.CharArrayReader;
6 import java.io.IOException;
7 import java.math.BigInteger;
8 import java.security.DigestException;
9 import java.security.KeyFactory;
10 import java.security.KeyPair;
11 import java.security.MessageDigest;
12 import java.security.NoSuchAlgorithmException;
13 import java.security.PrivateKey;
14 import java.security.PublicKey;
15 import java.security.spec.DSAPrivateKeySpec;
16 import java.security.spec.DSAPublicKeySpec;
17 import java.security.spec.ECParameterSpec;
18 import java.security.spec.ECPoint;
19 import java.security.spec.ECPrivateKeySpec;
20 import java.security.spec.ECPublicKeySpec;
21 import java.security.spec.InvalidKeySpecException;
22 import java.security.spec.KeySpec;
23 import java.security.spec.RSAPrivateCrtKeySpec;
24 import java.security.spec.RSAPrivateKeySpec;
25 import java.security.spec.RSAPublicKeySpec;
26
27 import com.trilead.ssh2.crypto.cipher.AES;
28 import com.trilead.ssh2.crypto.cipher.BlockCipher;
29 import com.trilead.ssh2.crypto.cipher.CBCMode;
30 import com.trilead.ssh2.crypto.cipher.DES;
31 import com.trilead.ssh2.crypto.cipher.DESede;
32 import com.trilead.ssh2.signature.ECDSASHA2Verify;
33
34 /**
35 * PEM Support.
36 *
37 * @author Christian Plattner, plattner@trilead.com
38 * @version $Id: PEMDecoder.java,v 1.2 2008/04/01 12:38:09 cplattne Exp $
39 */
40 public class PEMDecoder {
41 public static final int PEM_RSA_PRIVATE_KEY = 1;
42 public static final int PEM_DSA_PRIVATE_KEY = 2;
43 public static final int PEM_EC_PRIVATE_KEY = 3;
44
45 private static final int hexToInt(char c) {
46 if ((c >= 'a') && (c <= 'f')) {
47 return (c - 'a') + 10;
48 }
49
50 if ((c >= 'A') && (c <= 'F')) {
51 return (c - 'A') + 10;
52 }
53
54 if ((c >= '0') && (c <= '9')) {
55 return (c - '0');
56 }
57
58 throw new IllegalArgumentException("Need hex char");
59 }
60
61 private static byte[] hexToByteArray(String hex) {
62 if (hex == null)
63 throw new IllegalArgumentException("null argument");
64
65 if ((hex.length() % 2) != 0)
66 throw new IllegalArgumentException("Uneven string length in hex encoding.");
67
68 byte decoded[] = new byte[hex.length() / 2];
69
70 for (int i = 0; i < decoded.length; i++) {
71 int hi = hexToInt(hex.charAt(i * 2));
72 int lo = hexToInt(hex.charAt((i * 2) + 1));
73 decoded[i] = (byte)(hi * 16 + lo);
74 }
75
76 return decoded;
77 }
78
79 private static byte[] generateKeyFromPasswordSaltWithMD5(byte[] password, byte[] salt, int keyLen)
80 throws IOException {
81 if (salt.length < 8)
82 throw new IllegalArgumentException("Salt needs to be at least 8 bytes for key generation.");
83
84 MessageDigest md5;
85
86 try {
87 md5 = MessageDigest.getInstance("MD5");
88 }
89 catch (NoSuchAlgorithmException e) {
90 throw new IllegalArgumentException("VM does not support MD5", e);
91 }
92
93 byte[] key = new byte[keyLen];
94 byte[] tmp = new byte[md5.getDigestLength()];
95
96 while (true) {
97 md5.update(password, 0, password.length);
98 md5.update(salt, 0, 8); // ARGH we only use the first 8 bytes of the
99 // salt in this step.
100 // This took me two hours until I got AES-xxx running.
101 int copy = (keyLen < tmp.length) ? keyLen : tmp.length;
102
103 try {
104 md5.digest(tmp, 0, tmp.length);
105 }
106 catch (DigestException e) {
107 IOException ex = new IOException("could not digest password");
108 ex.initCause(e);
109 throw ex;
110 }
111
112 System.arraycopy(tmp, 0, key, key.length - keyLen, copy);
113 keyLen -= copy;
114
115 if (keyLen == 0)
116 return key;
117
118 md5.update(tmp, 0, tmp.length);
119 }
120 }
121
122 private static byte[] removePadding(byte[] buff, int blockSize) throws IOException {
123 /* Removes RFC 1423/PKCS #7 padding */
124 int rfc_1423_padding = buff[buff.length - 1] & 0xff;
125
126 if ((rfc_1423_padding < 1) || (rfc_1423_padding > blockSize))
127 throw new IOException("Decrypted PEM has wrong padding, did you specify the correct password?");
128
129 for (int i = 2; i <= rfc_1423_padding; i++) {
130 if (buff[buff.length - i] != rfc_1423_padding)
131 throw new IOException("Decrypted PEM has wrong padding, did you specify the correct password?");
132 }
133
134 byte[] tmp = new byte[buff.length - rfc_1423_padding];
135 System.arraycopy(buff, 0, tmp, 0, buff.length - rfc_1423_padding);
136 return tmp;
137 }
138
139 public static final PEMStructure parsePEM(char[] pem) throws IOException {
140 PEMStructure ps = new PEMStructure();
141 String line = null;
142 BufferedReader br = new BufferedReader(new CharArrayReader(pem));
143 String endLine = null;
144
145 while (true) {
146 line = br.readLine();
147
148 if (line == null)
149 throw new IOException("Invalid PEM structure, '-----BEGIN...' missing");
150
151 line = line.trim();
152
153 if (line.startsWith("-----BEGIN DSA PRIVATE KEY-----")) {
154 endLine = "-----END DSA PRIVATE KEY-----";
155 ps.pemType = PEM_DSA_PRIVATE_KEY;
156 break;
157 }
158
159 if (line.startsWith("-----BEGIN RSA PRIVATE KEY-----")) {
160 endLine = "-----END RSA PRIVATE KEY-----";
161 ps.pemType = PEM_RSA_PRIVATE_KEY;
162 break;
163 }
164
165 if (line.startsWith("-----BEGIN EC PRIVATE KEY-----")) {
166 endLine = "-----END EC PRIVATE KEY-----";
167 ps.pemType = PEM_EC_PRIVATE_KEY;
168 break;
169 }
170 }
171
172 while (true) {
173 line = br.readLine();
174
175 if (line == null)
176 throw new IOException("Invalid PEM structure, " + endLine + " missing");
177
178 line = line.trim();
179 int sem_idx = line.indexOf(':');
180
181 if (sem_idx == -1)
182 break;
183
184 String name = line.substring(0, sem_idx + 1);
185 String value = line.substring(sem_idx + 1);
186 String values[] = value.split(",");
187
188 for (int i = 0; i < values.length; i++)
189 values[i] = values[i].trim();
190
191 // Proc-Type: 4,ENCRYPTED
192 // DEK-Info: DES-EDE3-CBC,579B6BE3E5C60483
193
194 if ("Proc-Type:".equals(name)) {
195 ps.procType = values;
196 continue;
197 }
198
199 if ("DEK-Info:".equals(name)) {
200 ps.dekInfo = values;
201 continue;
202 }
203
204 /* Ignore line */
205 }
206
207 StringBuffer keyData = new StringBuffer();
208
209 while (true) {
210 if (line == null)
211 throw new IOException("Invalid PEM structure, " + endLine + " missing");
212
213 line = line.trim();
214
215 if (line.startsWith(endLine))
216 break;
217
218 keyData.append(line);
219 line = br.readLine();
220 }
221
222 char[] pem_chars = new char[keyData.length()];
223 keyData.getChars(0, pem_chars.length, pem_chars, 0);
224 ps.data = Base64.decode(pem_chars);
225
226 if (ps.data.length == 0)
227 throw new IOException("Invalid PEM structure, no data available");
228
229 return ps;
230 }
231
232 private static final void decryptPEM(PEMStructure ps, byte[] pw) throws IOException {
233 if (ps.dekInfo == null)
234 throw new IOException("Broken PEM, no mode and salt given, but encryption enabled");
235
236 if (ps.dekInfo.length != 2)
237 throw new IOException("Broken PEM, DEK-Info is incomplete!");
238
239 String algo = ps.dekInfo[0];
240 byte[] salt = hexToByteArray(ps.dekInfo[1]);
241 BlockCipher bc = null;
242
243 if (algo.equals("DES-EDE3-CBC")) {
244 DESede des3 = new DESede();
245 des3.init(false, generateKeyFromPasswordSaltWithMD5(pw, salt, 24));
246 bc = new CBCMode(des3, salt, false);
247 }
248 else if (algo.equals("DES-CBC")) {
249 DES des = new DES();
250 des.init(false, generateKeyFromPasswordSaltWithMD5(pw, salt, 8));
251 bc = new CBCMode(des, salt, false);
252 }
253 else if (algo.equals("AES-128-CBC")) {
254 AES aes = new AES();
255 aes.init(false, generateKeyFromPasswordSaltWithMD5(pw, salt, 16));
256 bc = new CBCMode(aes, salt, false);
257 }
258 else if (algo.equals("AES-192-CBC")) {
259 AES aes = new AES();
260 aes.init(false, generateKeyFromPasswordSaltWithMD5(pw, salt, 24));
261 bc = new CBCMode(aes, salt, false);
262 }
263 else if (algo.equals("AES-256-CBC")) {
264 AES aes = new AES();
265 aes.init(false, generateKeyFromPasswordSaltWithMD5(pw, salt, 32));
266 bc = new CBCMode(aes, salt, false);
267 }
268 else {
269 throw new IOException("Cannot decrypt PEM structure, unknown cipher " + algo);
270 }
271
272 if ((ps.data.length % bc.getBlockSize()) != 0)
273 throw new IOException("Invalid PEM structure, size of encrypted block is not a multiple of "
274 + bc.getBlockSize());
275
276 /* Now decrypt the content */
277 byte[] dz = new byte[ps.data.length];
278
279 for (int i = 0; i < ps.data.length / bc.getBlockSize(); i++) {
280 bc.transformBlock(ps.data, i * bc.getBlockSize(), dz, i * bc.getBlockSize());
281 }
282
283 /* Now check and remove RFC 1423/PKCS #7 padding */
284 dz = removePadding(dz, bc.getBlockSize());
285 ps.data = dz;
286 ps.dekInfo = null;
287 ps.procType = null;
288 }
289
290 public static final boolean isPEMEncrypted(PEMStructure ps) throws IOException {
291 if (ps.procType == null)
292 return false;
293
294 if (ps.procType.length != 2)
295 throw new IOException("Unknown Proc-Type field.");
296
297 if ("4".equals(ps.procType[0]) == false)
298 throw new IOException("Unknown Proc-Type field (" + ps.procType[0] + ")");
299
300 if ("ENCRYPTED".equals(ps.procType[1]))
301 return true;
302
303 return false;
304 }
305
306 public static KeyPair decode(char[] pem, String password) throws IOException {
307 PEMStructure ps = parsePEM(pem);
308 return decode(ps, password);
309 }
310
311 public static KeyPair decode(PEMStructure ps, String password) throws IOException {
312 if (isPEMEncrypted(ps)) {
313 if (password == null)
314 throw new IOException("PEM is encrypted, but no password was specified");
315
316 decryptPEM(ps, password.getBytes("ISO-8859-1"));
317 }
318
319 if (ps.pemType == PEM_DSA_PRIVATE_KEY) {
320 SimpleDERReader dr = new SimpleDERReader(ps.data);
321 byte[] seq = dr.readSequenceAsByteArray();
322
323 if (dr.available() != 0)
324 throw new IOException("Padding in DSA PRIVATE KEY DER stream.");
325
326 dr.resetInput(seq);
327 BigInteger version = dr.readInt();
328
329 if (version.compareTo(BigInteger.ZERO) != 0)
330 throw new IOException("Wrong version (" + version + ") in DSA PRIVATE KEY DER stream.");
331
332 BigInteger p = dr.readInt();
333 BigInteger q = dr.readInt();
334 BigInteger g = dr.readInt();
335 BigInteger y = dr.readInt();
336 BigInteger x = dr.readInt();
337
338 if (dr.available() != 0)
339 throw new IOException("Padding in DSA PRIVATE KEY DER stream.");
340
341 DSAPrivateKeySpec privSpec = new DSAPrivateKeySpec(x, p, q, g);
342 DSAPublicKeySpec pubSpec = new DSAPublicKeySpec(y, p, q, g);
343 return generateKeyPair("DSA", privSpec, pubSpec);
344 }
345
346 if (ps.pemType == PEM_RSA_PRIVATE_KEY) {
347 SimpleDERReader dr = new SimpleDERReader(ps.data);
348 byte[] seq = dr.readSequenceAsByteArray();
349
350 if (dr.available() != 0)
351 throw new IOException("Padding in RSA PRIVATE KEY DER stream.");
352
353 dr.resetInput(seq);
354 BigInteger version = dr.readInt();
355
356 if ((version.compareTo(BigInteger.ZERO) != 0) && (version.compareTo(BigInteger.ONE) != 0))
357 throw new IOException("Wrong version (" + version + ") in RSA PRIVATE KEY DER stream.");
358
359 BigInteger n = dr.readInt();
360 BigInteger e = dr.readInt();
361 BigInteger d = dr.readInt();
362 // TODO: is this right?
363 BigInteger primeP = dr.readInt();
364 BigInteger primeQ = dr.readInt();
365 BigInteger expP = dr.readInt();
366 BigInteger expQ = dr.readInt();
367 BigInteger coeff = dr.readInt();
368 RSAPrivateKeySpec privSpec = new RSAPrivateCrtKeySpec(n, e, d, primeP, primeQ, expP, expQ, coeff);
369 RSAPublicKeySpec pubSpec = new RSAPublicKeySpec(n, e);
370 return generateKeyPair("RSA", privSpec, pubSpec);
371 }
372
373 if (ps.pemType == PEM_EC_PRIVATE_KEY) {
374 SimpleDERReader dr = new SimpleDERReader(ps.data);
375 byte[] seq = dr.readSequenceAsByteArray();
376
377 if (dr.available() != 0)
378 throw new IOException("Padding in EC PRIVATE KEY DER stream.");
379
380 dr.resetInput(seq);
381 BigInteger version = dr.readInt();
382
383 if ((version.compareTo(BigInteger.ONE) != 0))
384 throw new IOException("Wrong version (" + version + ") in EC PRIVATE KEY DER stream.");
385
386 byte[] privateBytes = dr.readOctetString();
387 String curveOid = null;
388 byte[] publicBytes = null;
389
390 while (dr.available() > 0) {
391 int type = dr.readConstructedType();
392 SimpleDERReader cr = dr.readConstructed();
393
394 switch (type) {
395 case 0:
396 curveOid = cr.readOid();
397 break;
398
399 case 1:
400 publicBytes = cr.readOctetString();
401 break;
402 }
403 }
404
405 ECParameterSpec params = ECDSASHA2Verify.getCurveForOID(curveOid);
406
407 if (params == null)
408 throw new IOException("invalid OID");
409
410 BigInteger s = new BigInteger(privateBytes);
411 byte[] publicBytesSlice = new byte[publicBytes.length - 1];
412 System.arraycopy(publicBytes, 1, publicBytesSlice, 0, publicBytesSlice.length);
413 ECPoint w = ECDSASHA2Verify.decodeECPoint(publicBytesSlice, params.getCurve());
414 ECPrivateKeySpec privSpec = new ECPrivateKeySpec(s, params);
415 ECPublicKeySpec pubSpec = new ECPublicKeySpec(w, params);
416 return generateKeyPair("EC", privSpec, pubSpec);
417 }
418
419 throw new IOException("PEM problem: it is of unknown type");
420 }
421
422 /**
423 * Generate a {@code KeyPair} given an {@code algorithm} and {@code KeySpec}.
424 */
425 private static KeyPair generateKeyPair(String algorithm, KeySpec privSpec, KeySpec pubSpec)
426 throws IOException {
427 try {
428 final KeyFactory kf = KeyFactory.getInstance(algorithm);
429 final PublicKey pubKey = kf.generatePublic(pubSpec);
430 final PrivateKey privKey = kf.generatePrivate(privSpec);
431 return new KeyPair(pubKey, privKey);
432 }
433 catch (NoSuchAlgorithmException ex) {
434 IOException ioex = new IOException();
435 ioex.initCause(ex);
436 throw ioex;
437 }
438 catch (InvalidKeySpecException ex) {
439 IOException ioex = new IOException("invalid keyspec");
440 ioex.initCause(ex);
441 throw ioex;
442 }
443 }
444 }