Bug Summary

File:lib/auth/rsa.c
Location:line 117, column 7
Description:Value stored to 'ret' 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 <random.h>
41#include <gnutls_mpi.h>
42#include <abstract_int.h>
43
44int _gnutls_gen_rsa_client_kx (gnutls_session_t, gnutls_buffer_st*);
45static int proc_rsa_client_kx (gnutls_session_t, opaque *, size_t);
46
47const mod_auth_st rsa_auth_struct = {
48 "RSA",
49 _gnutls_gen_cert_server_certificate,
50 _gnutls_gen_cert_client_certificate,
51 NULL((void*)0), /* gen server kx */
52 _gnutls_gen_rsa_client_kx,
53 _gnutls_gen_cert_client_cert_vrfy, /* gen client cert vrfy */
54 _gnutls_gen_cert_server_cert_req, /* server cert request */
55
56 _gnutls_proc_certificate,
57 _gnutls_proc_certificate,
58 NULL((void*)0), /* proc server kx */
59 proc_rsa_client_kx, /* proc client kx */
60 _gnutls_proc_cert_client_cert_vrfy, /* proc client cert vrfy */
61 _gnutls_proc_cert_cert_req /* proc server cert request */
62};
63
64/* This function reads the RSA parameters from peer's certificate;
65 */
66static int
67_gnutls_get_public_rsa_params (gnutls_session_t session,
68 gnutls_pk_params_st * params)
69{
70 int ret;
71 cert_auth_info_t info;
72 gnutls_pcert_st peer_cert;
73 int i;
74
75 /* normal non export case */
76
77 info = _gnutls_get_auth_info (session);
78
79 if (info == NULL((void*)0) || info->ncerts == 0)
80 {
81 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa.c",81); } while(0);;
82 return GNUTLS_E_INTERNAL_ERROR-59;
83 }
84
85 ret =
86 _gnutls_get_auth_info_pcert (&peer_cert,
87 session->security_parameters.cert_type,
88 info);
89
90 if (ret < 0)
91 {
92 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa.c",92); } while(0);;
93 return ret;
94 }
95
96 gnutls_pk_params_init(params);
97 params->params_nr = RSA_PUBLIC_PARAMS2;
98
99 /* EXPORT case: */
100 if (_gnutls_cipher_suite_get_kx_algo
101 (session->security_parameters.cipher_suite) ==
102 GNUTLS_KX_RSA_EXPORT &&
103 _gnutls_pubkey_is_over_rsa_512(peer_cert.pubkey) == 0)
104 {
105 if (session->key->rsa[0] == NULL((void*)0) || session->key->rsa[1] == NULL((void*)0))
106 {
107 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa.c",107); } while(0);;
108 ret = GNUTLS_E_INTERNAL_ERROR-59;
109 goto cleanup;
110 }
111
112 for (i = 0; i < params->params_nr; i++)
113 {
114 params->params[i] = _gnutls_mpi_copy (session->key->rsa[i])_gnutls_mpi_ops.bigint_set(((void*)0),session->key->rsa
[i]);
115 }
116
117 ret = 0;
Value stored to 'ret' is never read
118 goto cleanup;
119 }
120
121 ret = _gnutls_pubkey_get_mpis(peer_cert.pubkey, params);
122 if (ret < 0)
123 {
124 ret = gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR)gnutls_assert_val_int(-59, "rsa.c", 124);
125 goto cleanup;
126 }
127
128 ret = 0;
129
130cleanup:
131 gnutls_pcert_deinit (&peer_cert);
132
133 return 0;
134}
135
136static int
137proc_rsa_client_kx (gnutls_session_t session, opaque * data,
138 size_t _data_size)
139{
140 gnutls_datum_t plaintext;
141 gnutls_datum_t ciphertext;
142 int ret, dsize;
143 int randomize_key = 0;
144 ssize_t data_size = _data_size;
145
146 if (gnutls_protocol_get_version_gnutls_protocol_get_version (session) == GNUTLS_SSL3)
147 {
148 /* SSL 3.0
149 */
150 ciphertext.data = data;
151 ciphertext.size = data_size;
152 }
153 else
154 {
155 /* TLS 1.0
156 */
157 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.c",157); } while(0);; return -9;} } while (0);
158 ciphertext.data = &data[2];
159 dsize = _gnutls_read_uint16 (data);
160
161 if (dsize != data_size)
162 {
163 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa.c",163); } while(0);;
164 return GNUTLS_E_UNEXPECTED_PACKET_LENGTH-9;
165 }
166 ciphertext.size = dsize;
167 }
168
169 ret =
170 gnutls_privkey_decrypt_data (session->internals.selected_key, 0,
171 &ciphertext, &plaintext);
172
173 if (ret < 0 || plaintext.size != GNUTLS_MASTER_SIZE48)
174 {
175 /* In case decryption fails then don't inform
176 * the peer. Just use a random key. (in order to avoid
177 * attack against pkcs-1 formating).
178 */
179 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa.c",179); } while(0);;
180 _gnutls_audit_log (session, "auth_rsa: Possible PKCS #1 format attack\n");
181 randomize_key = 1;
182 }
183 else
184 {
185 /* If the secret was properly formatted, then
186 * check the version number.
187 */
188 if (_gnutls_get_adv_version_major (session)session->internals.adv_version_major != plaintext.data[0]
189 || _gnutls_get_adv_version_minor (session)session->internals.adv_version_minor != plaintext.data[1])
190 {
191 /* No error is returned here, if the version number check
192 * fails. We proceed normally.
193 * That is to defend against the attack described in the paper
194 * "Attacking RSA-based sessions in SSL/TLS" by Vlastimil Klima,
195 * Ondej Pokorny and Tomas Rosa.
196 */
197 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa.c",197); } while(0);;
198 _gnutls_audit_log
199 (session, "auth_rsa: Possible PKCS #1 version check format attack\n");
200 }
201 }
202
203 if (randomize_key != 0)
204 {
205 session->key->key.size = GNUTLS_MASTER_SIZE48;
206 session->key->key.data = gnutls_malloc (session->key->key.size);
207 if (session->key->key.data == NULL((void*)0))
208 {
209 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa.c",209); } while(0);;
210 return GNUTLS_E_MEMORY_ERROR-25;
211 }
212
213 /* we do not need strong random numbers here.
214 */
215 ret = _gnutls_rnd (GNUTLS_RND_NONCE, session->key->key.data,
216 session->key->key.size);
217 if (ret < 0)
218 {
219 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa.c",219); } while(0);;
220 return ret;
221 }
222
223 }
224 else
225 {
226 session->key->key.data = plaintext.data;
227 session->key->key.size = plaintext.size;
228 }
229
230 /* This is here to avoid the version check attack
231 * discussed above.
232 */
233 session->key->key.data[0] = _gnutls_get_adv_version_major (session)session->internals.adv_version_major;
234 session->key->key.data[1] = _gnutls_get_adv_version_minor (session)session->internals.adv_version_minor;
235
236 return 0;
237}
238
239
240
241/* return RSA(random) using the peers public key
242 */
243int
244_gnutls_gen_rsa_client_kx (gnutls_session_t session, gnutls_buffer_st* data)
245{
246 cert_auth_info_t auth = session->key->auth_info;
247 gnutls_datum_t sdata; /* data to send */
248 gnutls_pk_params_st params;
249 int ret;
250 gnutls_protocol_t ver;
251
252 if (auth == NULL((void*)0))
253 {
254 /* this shouldn't have happened. The proc_certificate
255 * function should have detected that.
256 */
257 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa.c",257); } while(0);;
258 return GNUTLS_E_INSUFFICIENT_CREDENTIALS-32;
259 }
260
261 session->key->key.size = GNUTLS_MASTER_SIZE48;
262 session->key->key.data = gnutls_malloc (session->key->key.size);
263
264 if (session->key->key.data == NULL((void*)0))
265 {
266 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa.c",266); } while(0);;
267 return GNUTLS_E_MEMORY_ERROR-25;
268 }
269
270 ret = _gnutls_rnd (GNUTLS_RND_RANDOM, session->key->key.data,
271 session->key->key.size);
272 if (ret < 0)
273 {
274 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa.c",274); } while(0);;
275 return ret;
276 }
277
278 ver = _gnutls_get_adv_version (session);
279
280 if (session->internals.rsa_pms_version[0] == 0)
281 {
282 session->key->key.data[0] = _gnutls_version_get_major (ver);
283 session->key->key.data[1] = _gnutls_version_get_minor (ver);
284 }
285 else
286 { /* use the version provided */
287 session->key->key.data[0] = session->internals.rsa_pms_version[0];
288 session->key->key.data[1] = session->internals.rsa_pms_version[1];
289 }
290
291 /* move RSA parameters to key (session).
292 */
293 if ((ret =
294 _gnutls_get_public_rsa_params (session, &params)) < 0)
295 {
296 gnutls_assert ()do { if (__builtin_expect((_gnutls_log_level >= 2), 0)) _gnutls_log
( 2, "ASSERT: %s:%d\n", "rsa.c",296); } while(0);;
297 return ret;
298 }
299
300 ret =
301 _gnutls_pkcs1_rsa_encrypt (&sdata, &session->key->key,
302 &params, 2);
303
304 gnutls_pk_params_release(&params);
305
306 if (ret < 0)
307 return gnutls_assert_val(ret)gnutls_assert_val_int(ret, "rsa.c", 307);
308
309
310 if (gnutls_protocol_get_version_gnutls_protocol_get_version (session) == GNUTLS_SSL3)
311 {
312 /* SSL 3.0 */
313 _gnutls_buffer_replace_data( data, &sdata);
314
315 return data->length;
316 }
317 else
318 { /* TLS 1 */
319 ret = _gnutls_buffer_append_data_prefix( data, 16, sdata.data, sdata.size);
320
321 _gnutls_free_datum (&sdata)_gnutls_free_datum_m(&sdata, gnutls_free);
322 return ret;
323 }
324
325}