Bug Summary

File:lib/auth/rsa_export.c
Location:line 412, column 3
Description:Value stored to 'i' is never read

Annotated Source Code

1/*
2 * Copyright (C) 2000-2012 Free Software Foundation, Inc.
3 *
4 * Author: Nikos Mavrogiannopoulos
5 *
6 * This file is part of GnuTLS.
7 *
8 * The GnuTLS is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public License
10 * as published by the Free Software Foundation; either version 3 of
11 * the License, or (at your option) any later version.
12 *
13 * This library is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public License
19 * along with this program. If not, see <http://www.gnu.org/licenses/>
20 *
21 */
22
23/* This file contains the RSA key exchange part of the certificate
24 * authentication.
25 */
26
27#include "gnutls_int.h"
28#include "gnutls_auth.h"
29#include "gnutls_errors.h"
30#include "gnutls_dh.h"
31#include "gnutls_num.h"
32#include "gnutls_datum.h"
33#include <auth/cert.h>
34#include <gnutls_pk.h>
35#include <algorithms.h>
36#include <gnutls_global.h>
37#include "debug.h"
38#include <gnutls_sig.h>
39#include <gnutls_x509.h>
40#include <gnutls_rsa_export.h>
41#include <gnutls_state.h>
42#include <random.h>
43#include <abstract_int.h>
44
45int _gnutls_gen_rsa_client_kx (gnutls_session_t, gnutls_buffer_st*);
46static int gen_rsa_export_server_kx (gnutls_session_t, gnutls_buffer_st*);
47static int proc_rsa_export_server_kx (gnutls_session_t, opaque *, size_t);
48static int proc_rsa_export_client_kx (gnutls_session_t session, opaque * data,
49 size_t _data_size);
50
51const mod_auth_st rsa_export_auth_struct = {
52 "RSA EXPORT",
53 _gnutls_gen_cert_server_certificate,
54 _gnutls_gen_cert_client_certificate,
55 gen_rsa_export_server_kx,
56 _gnutls_gen_rsa_client_kx,
57 _gnutls_gen_cert_client_cert_vrfy, /* gen client cert vrfy */
58 _gnutls_gen_cert_server_cert_req, /* server cert request */
59
60 _gnutls_proc_certificate,
61 _gnutls_proc_certificate,
62 proc_rsa_export_server_kx,
63 proc_rsa_export_client_kx, /* proc client kx */
64 _gnutls_proc_cert_client_cert_vrfy, /* proc client cert vrfy */
65 _gnutls_proc_cert_cert_req /* proc server cert request */
66};
67
68/* This function reads the RSA parameters from the private key
69 */
70static int
71_gnutls_get_private_rsa_params (gnutls_session_t session,
72 gnutls_pk_params_st** params)
73{
74 int ret;
75 gnutls_certificate_credentials_t cred;
76 gnutls_rsa_params_t rsa_params;
77
78 cred = (gnutls_certificate_credentials_t)
79 _gnutls_get_cred (session->key, GNUTLS_CRD_CERTIFICATE, NULL((void*)0));
80 if (cred == NULL((void*)0))
81 {
82 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",82); } while(0);;
83 return GNUTLS_E_INSUFFICIENT_CREDENTIALS-32;
84 }
85
86 if (session->internals.selected_cert_list == NULL((void*)0))
87 {
88 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",88); } while(0);;
89 return GNUTLS_E_INSUFFICIENT_CREDENTIALS-32;
90 }
91
92 ret = _gnutls_pubkey_is_over_rsa_512(session->internals.selected_cert_list[0].pubkey);
93
94 if (_gnutls_cipher_suite_get_kx_algo
95 (session->security_parameters.cipher_suite)
96 != GNUTLS_KX_RSA_EXPORT || ret < 0)
97 {
98 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",98); } while(0);;
99 return GNUTLS_E_INVALID_REQUEST-50;
100 }
101
102 rsa_params =
103 _gnutls_certificate_get_rsa_params (cred->rsa_params,
104 cred->params_func, session);
105 /* EXPORT case: */
106 if (rsa_params == NULL((void*)0))
107 {
108 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",108); } while(0);;
109 return GNUTLS_E_NO_TEMPORARY_RSA_PARAMS-84;
110 }
111
112 /* In the export case, we do use temporary RSA params
113 * of 512 bits size. The params in the certificate are
114 * used to sign this temporary stuff.
115 */
116 *params = &rsa_params->params;
117
118 return 0;
119}
120
121int
122proc_rsa_export_client_kx (gnutls_session_t session, opaque * data,
123 size_t _data_size)
124{
125 gnutls_datum_t plaintext;
126 gnutls_datum_t ciphertext;
127 int ret, dsize;
128 gnutls_pk_params_st *params;
129 int randomize_key = 0;
130 ssize_t data_size = _data_size;
131
132 if (gnutls_protocol_get_version_gnutls_protocol_get_version (session) == GNUTLS_SSL3)
133 {
134 /* SSL 3.0
135 */
136 ciphertext.data = data;
137 ciphertext.size = data_size;
138 }
139 else
140 {
141 /* TLS 1.0
142 */
143 DECR_LEN (data_size, 2)do { data_size-=2; if (data_size<0) {do { if (__builtin_expect
((_gnutls_log_level >= 2), 0)) _gnutls_log( 2, "ASSERT: %s:%d\n"
, "rsa_export.c",143); } while(0);; return -9;} } while (0);
144 ciphertext.data = &data[2];
145 dsize = _gnutls_read_uint16 (data);
146
147 if (dsize != data_size)
148 {
149 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",149); } while(0);;
150 return GNUTLS_E_UNEXPECTED_PACKET_LENGTH-9;
151 }
152 ciphertext.size = dsize;
153 }
154
155 ret = _gnutls_get_private_rsa_params (session, &params);
156 if (ret < 0)
157 {
158 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",158); } while(0);;
159 return ret;
160 }
161
162 ret = _gnutls_pkcs1_rsa_decrypt (&plaintext, &ciphertext, params, 2); /* btype==2 */
163
164 if (ret < 0 || plaintext.size != GNUTLS_MASTER_SIZE48)
165 {
166 /* In case decryption fails then don't inform
167 * the peer. Just use a random key. (in order to avoid
168 * attack against pkcs-1 formating).
169 */
170 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",170); } while(0);;
171 _gnutls_audit_log (session, "auth_rsa: Possible PKCS #1 format attack\n");
172 randomize_key = 1;
173 }
174 else
175 {
176 /* If the secret was properly formatted, then
177 * check the version number.
178 */
179 if (_gnutls_get_adv_version_major (session)session->internals.adv_version_major != plaintext.data[0]
180 || _gnutls_get_adv_version_minor (session)session->internals.adv_version_minor != plaintext.data[1])
181 {
182 /* No error is returned here, if the version number check
183 * fails. We proceed normally.
184 * That is to defend against the attack described in the paper
185 * "Attacking RSA-based sessions in SSL/TLS" by Vlastimil Klima,
186 * Ondej Pokorny and Tomas Rosa.
187 */
188 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",188); } while(0);;
189 _gnutls_audit_log
190 (session, "auth_rsa: Possible PKCS #1 version check format attack\n");
191 }
192 }
193
194 if (randomize_key != 0)
195 {
196 session->key->key.size = GNUTLS_MASTER_SIZE48;
197 session->key->key.data = gnutls_malloc (session->key->key.size);
198 if (session->key->key.data == NULL((void*)0))
199 {
200 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",200); } while(0);;
201 return GNUTLS_E_MEMORY_ERROR-25;
202 }
203
204 /* we do not need strong random numbers here.
205 */
206 ret = _gnutls_rnd (GNUTLS_RND_NONCE, session->key->key.data,
207 session->key->key.size);
208 if (ret < 0)
209 {
210 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",210); } while(0);;
211 return ret;
212 }
213
214 }
215 else
216 {
217 session->key->key.data = plaintext.data;
218 session->key->key.size = plaintext.size;
219 }
220
221 /* This is here to avoid the version check attack
222 * discussed above.
223 */
224 session->key->key.data[0] = _gnutls_get_adv_version_major (session)session->internals.adv_version_major;
225 session->key->key.data[1] = _gnutls_get_adv_version_minor (session)session->internals.adv_version_minor;
226
227 return 0;
228}
229
230static int
231gen_rsa_export_server_kx (gnutls_session_t session, gnutls_buffer_st* data)
232{
233 gnutls_rsa_params_t rsa_params;
234 const gnutls_pk_params_st *rsa_mpis;
235 int ret = 0;
236 gnutls_pcert_st *apr_cert_list;
237 gnutls_privkey_t apr_pkey;
238 int apr_cert_list_length;
239 gnutls_datum_t signature, ddata;
240 gnutls_certificate_credentials_t cred;
241 gnutls_sign_algorithm_t sign_algo;
242 unsigned int bits = 0;
243
244 cred = (gnutls_certificate_credentials_t)
245 _gnutls_get_cred (session->key, GNUTLS_CRD_CERTIFICATE, NULL((void*)0));
246 if (cred == NULL((void*)0))
247 {
248 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",248); } while(0);;
249 return GNUTLS_E_INSUFFICIENT_CREDENTIALS-32;
250 }
251
252 /* find the appropriate certificate */
253 if ((ret =
254 _gnutls_get_selected_cert (session, &apr_cert_list,
255 &apr_cert_list_length, &apr_pkey)) < 0)
256 {
257 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",257); } while(0);;
258 return ret;
259 }
260
261 /* abort sending this message if we have a certificate
262 * of 512 bits or less.
263 */
264 gnutls_privkey_get_pk_algorithm (apr_pkey, &bits);
265 if (apr_pkey && bits <= 512)
266 {
267 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",267); } while(0);;
268 return GNUTLS_E_INT_RET_0-1251;
269 }
270
271 rsa_params =
272 _gnutls_certificate_get_rsa_params (cred->rsa_params, cred->params_func,
273 session);
274 rsa_mpis = _gnutls_rsa_params_to_mpi (rsa_params);
275 if (rsa_mpis == NULL((void*)0))
276 {
277 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",277); } while(0);;
278 return GNUTLS_E_NO_TEMPORARY_RSA_PARAMS-84;
279 }
280
281 if ((ret = _gnutls_auth_info_set (session, GNUTLS_CRD_CERTIFICATE,
282 sizeof (cert_auth_info_st), 0)) < 0)
283 {
284 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",284); } while(0);;
285 return ret;
286 }
287
288 _gnutls_rsa_export_set_pubkey (session, rsa_mpis->params[1], rsa_mpis->params[0]);
289
290 ret = _gnutls_buffer_append_mpi( data, 16, rsa_mpis->params[0], 0);
291 if (ret < 0)
292 return gnutls_assert_val(ret)gnutls_assert_val_int(ret, "rsa_export.c", 292);
293
294 ret = _gnutls_buffer_append_mpi( data, 16, rsa_mpis->params[1], 0);
295 if (ret < 0)
296 return gnutls_assert_val(ret)gnutls_assert_val_int(ret, "rsa_export.c", 296);
297
298 /* Generate the signature. */
299
300 ddata.data = data->data;
301 ddata.size = data->length;
302
303 if (apr_cert_list_length > 0)
304 {
305 if ((ret =
306 _gnutls_handshake_sign_data (session, &apr_cert_list[0],
307 apr_pkey, &ddata, &signature,
308 &sign_algo)) < 0)
309 {
310 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",310); } while(0);;
311 return ret;
312 }
313 }
314 else
315 {
316 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",316); } while(0);;
317 return data->length; /* do not put a signature - ILLEGAL! */
318 }
319
320 ret = _gnutls_buffer_append_data_prefix( data, 16, signature.data, signature.size);
321 _gnutls_free_datum (&signature)_gnutls_free_datum_m(&signature, gnutls_free);
322
323 if (ret < 0)
324 return gnutls_assert_val(ret)gnutls_assert_val_int(ret, "rsa_export.c", 324);
325
326 return data->length;
327}
328
329/* if the peer's certificate is of 512 bits or less, returns non (0).
330 */
331int
332_gnutls_peers_cert_less_512 (gnutls_session_t session)
333{
334 gnutls_pcert_st peer_cert;
335 int ret;
336 cert_auth_info_t info = _gnutls_get_auth_info (session);
337
338 if (info == NULL((void*)0) || info->ncerts == 0)
339 {
340 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",340); } while(0);;
341 /* we need this in order to get peer's certificate */
342 return 0;
343 }
344
345 if ((ret =
346 _gnutls_get_auth_info_pcert (&peer_cert,
347 session->security_parameters.cert_type,
348 info)) < 0)
349 {
350 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",350); } while(0);;
351 return 0;
352 }
353
354 if (gnutls_pubkey_get_pk_algorithm(peer_cert.pubkey, NULL((void*)0)) != GNUTLS_PK_RSA)
355 {
356 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",356); } while(0);;
357 gnutls_pcert_deinit (&peer_cert);
358 return 0;
359 }
360
361 if (_gnutls_pubkey_is_over_rsa_512(peer_cert.pubkey) < 0)
362 {
363 gnutls_pcert_deinit (&peer_cert);
364 return 1;
365 }
366
367 gnutls_pcert_deinit (&peer_cert);
368
369 return 0;
370}
371
372static int
373proc_rsa_export_server_kx (gnutls_session_t session,
374 opaque * data, size_t _data_size)
375{
376 uint16_t n_m, n_e;
377 size_t _n_m, _n_e;
378 uint8_t *data_m;
379 uint8_t *data_e;
380 int i, sigsize;
381 gnutls_datum_t vparams, signature;
382 int ret;
383 ssize_t data_size = _data_size;
384 cert_auth_info_t info;
385 gnutls_pcert_st peer_cert;
386
387 info = _gnutls_get_auth_info (session);
388 if (info == NULL((void*)0) || info->ncerts == 0)
389 {
390 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",390); } while(0);;
391 /* we need this in order to get peer's certificate */
392 return GNUTLS_E_INTERNAL_ERROR-59;
393 }
394
395
396 i = 0;
397
398 DECR_LEN (data_size, 2)do { data_size-=2; if (data_size<0) {do { if (__builtin_expect
((_gnutls_log_level >= 2), 0)) _gnutls_log( 2, "ASSERT: %s:%d\n"
, "rsa_export.c",398); } while(0);; return -9;} } while (0);
399 n_m = _gnutls_read_uint16 (&data[i]);
400 i += 2;
401
402 DECR_LEN (data_size, n_m)do { data_size-=n_m; if (data_size<0) {do { if (__builtin_expect
((_gnutls_log_level >= 2), 0)) _gnutls_log( 2, "ASSERT: %s:%d\n"
, "rsa_export.c",402); } while(0);; return -9;} } while (0);
403 data_m = &data[i];
404 i += n_m;
405
406 DECR_LEN (data_size, 2)do { data_size-=2; if (data_size<0) {do { if (__builtin_expect
((_gnutls_log_level >= 2), 0)) _gnutls_log( 2, "ASSERT: %s:%d\n"
, "rsa_export.c",406); } while(0);; return -9;} } while (0);
407 n_e = _gnutls_read_uint16 (&data[i]);
408 i += 2;
409
410 DECR_LEN (data_size, n_e)do { data_size-=n_e; if (data_size<0) {do { if (__builtin_expect
((_gnutls_log_level >= 2), 0)) _gnutls_log( 2, "ASSERT: %s:%d\n"
, "rsa_export.c",410); } while(0);; return -9;} } while (0);
411 data_e = &data[i];
412 i += n_e;
Value stored to 'i' is never read
413
414 _n_e = n_e;
415 _n_m = n_m;
416
417 if (_gnutls_mpi_scan_nz (&session->key->rsa[0], data_m, _n_m) != 0)
418 {
419 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",419); } while(0);;
420 return GNUTLS_E_MPI_SCAN_FAILED-23;
421 }
422
423 if (_gnutls_mpi_scan_nz (&session->key->rsa[1], data_e, _n_e) != 0)
424 {
425 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",425); } while(0);;
426 return GNUTLS_E_MPI_SCAN_FAILED-23;
427 }
428
429 _gnutls_rsa_export_set_pubkey (session, session->key->rsa[1],
430 session->key->rsa[0]);
431
432 /* VERIFY SIGNATURE */
433
434 vparams.size = n_m + n_e + 4;
435 vparams.data = data;
436
437 DECR_LEN (data_size, 2)do { data_size-=2; if (data_size<0) {do { if (__builtin_expect
((_gnutls_log_level >= 2), 0)) _gnutls_log( 2, "ASSERT: %s:%d\n"
, "rsa_export.c",437); } while(0);; return -9;} } while (0);
438 sigsize = _gnutls_read_uint16 (&data[vparams.size]);
439
440 DECR_LEN (data_size, sigsize)do { data_size-=sigsize; if (data_size<0) {do { if (__builtin_expect
((_gnutls_log_level >= 2), 0)) _gnutls_log( 2, "ASSERT: %s:%d\n"
, "rsa_export.c",440); } while(0);; return -9;} } while (0);
441 signature.data = &data[vparams.size + 2];
442 signature.size = sigsize;
443
444 if ((ret =
445 _gnutls_get_auth_info_pcert (&peer_cert,
446 session->security_parameters.cert_type,
447 info)) < 0)
448 {
449 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",449); } while(0);;
450 return ret;
451 }
452
453 ret =
454 _gnutls_handshake_verify_data (session, &peer_cert, &vparams, &signature,
455 GNUTLS_SIGN_UNKNOWN);
456
457 gnutls_pcert_deinit (&peer_cert);
458 if (ret < 0)
459 {
460 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa_export.c",460); } while(0);;
461 }
462
463 return ret;
464}