1 /* ssl/tls_srp.c */
2 /* Written by Christophe Renou (christophe.renou@edelweb.fr) with
3 * the precious help of Peter Sylvester (peter.sylvester@edelweb.fr)
4 * for the EdelKey project and contributed to the OpenSSL project 2004.
5 */
6 /* ====================================================================
7 * Copyright (c) 2004-2011 The OpenSSL Project. All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 *
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 *
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in
18 * the documentation and/or other materials provided with the
19 * distribution.
20 *
21 * 3. All advertising materials mentioning features or use of this
22 * software must display the following acknowledgment:
23 * "This product includes software developed by the OpenSSL Project
24 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
25 *
26 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
27 * endorse or promote products derived from this software without
28 * prior written permission. For written permission, please contact
29 * licensing@OpenSSL.org.
30 *
31 * 5. Products derived from this software may not be called "OpenSSL"
32 * nor may "OpenSSL" appear in their names without prior written
33 * permission of the OpenSSL Project.
34 *
35 * 6. Redistributions of any form whatsoever must retain the following
36 * acknowledgment:
37 * "This product includes software developed by the OpenSSL Project
38 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
39 *
40 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
41 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
43 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
44 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
45 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
46 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
47 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
49 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
50 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
51 * OF THE POSSIBILITY OF SUCH DAMAGE.
52 * ====================================================================
53 *
54 * This product includes cryptographic software written by Eric Young
55 * (eay@cryptsoft.com). This product includes software written by Tim
56 * Hudson (tjh@cryptsoft.com).
57 *
58 */
59 #include "ssl_locl.h"
60 #ifndef OPENSSL_NO_SRP
61
62 #include <openssl/rand.h>
63 #include <openssl/srp.h>
64 #include <openssl/err.h>
65
66 int SSL_CTX_SRP_CTX_free(struct ssl_ctx_st *ctx)
67 {
68 if (ctx == NULL)
69 return 0;
70 OPENSSL_free(ctx->srp_ctx.login);
71 BN_free(ctx->srp_ctx.N);
72 BN_free(ctx->srp_ctx.g);
73 BN_free(ctx->srp_ctx.s);
74 BN_free(ctx->srp_ctx.B);
75 BN_free(ctx->srp_ctx.A);
76 BN_free(ctx->srp_ctx.a);
77 BN_free(ctx->srp_ctx.b);
78 BN_free(ctx->srp_ctx.v);
79 ctx->srp_ctx.TLS_ext_srp_username_callback = NULL;
80 ctx->srp_ctx.SRP_cb_arg = NULL;
81 ctx->srp_ctx.SRP_verify_param_callback = NULL;
82 ctx->srp_ctx.SRP_give_srp_client_pwd_callback = NULL;
83 ctx->srp_ctx.N = NULL;
84 ctx->srp_ctx.g = NULL;
85 ctx->srp_ctx.s = NULL;
86 ctx->srp_ctx.B = NULL;
87 ctx->srp_ctx.A = NULL;
88 ctx->srp_ctx.a = NULL;
89 ctx->srp_ctx.b = NULL;
90 ctx->srp_ctx.v = NULL;
91 ctx->srp_ctx.login = NULL;
92 ctx->srp_ctx.info = NULL;
93 ctx->srp_ctx.strength = SRP_MINIMAL_N;
94 ctx->srp_ctx.srp_Mask = 0;
95 return (1);
96 }
97
98 int SSL_SRP_CTX_free(struct ssl_st *s)
99 {
100 if (s == NULL)
101 return 0;
102 OPENSSL_free(s->srp_ctx.login);
103 BN_free(s->srp_ctx.N);
104 BN_free(s->srp_ctx.g);
105 BN_free(s->srp_ctx.s);
106 BN_free(s->srp_ctx.B);
107 BN_free(s->srp_ctx.A);
108 BN_free(s->srp_ctx.a);
109 BN_free(s->srp_ctx.b);
110 BN_free(s->srp_ctx.v);
111 s->srp_ctx.TLS_ext_srp_username_callback = NULL;
112 s->srp_ctx.SRP_cb_arg = NULL;
113 s->srp_ctx.SRP_verify_param_callback = NULL;
114 s->srp_ctx.SRP_give_srp_client_pwd_callback = NULL;
115 s->srp_ctx.N = NULL;
116 s->srp_ctx.g = NULL;
117 s->srp_ctx.s = NULL;
118 s->srp_ctx.B = NULL;
119 s->srp_ctx.A = NULL;
120 s->srp_ctx.a = NULL;
121 s->srp_ctx.b = NULL;
122 s->srp_ctx.v = NULL;
123 s->srp_ctx.login = NULL;
124 s->srp_ctx.info = NULL;
125 s->srp_ctx.strength = SRP_MINIMAL_N;
126 s->srp_ctx.srp_Mask = 0;
127 return (1);
128 }
129
130 int SSL_SRP_CTX_init(struct ssl_st *s)
131 {
132 SSL_CTX *ctx;
133
134 if ((s == NULL) || ((ctx = s->ctx) == NULL))
135 return 0;
136 s->srp_ctx.SRP_cb_arg = ctx->srp_ctx.SRP_cb_arg;
137 /* set client Hello login callback */
138 s->srp_ctx.TLS_ext_srp_username_callback = ctx->srp_ctx.TLS_ext_srp_username_callback;
139 /* set SRP N/g param callback for verification */
140 s->srp_ctx.SRP_verify_param_callback = ctx->srp_ctx.SRP_verify_param_callback;
141 /* set SRP client passwd callback */
142 s->srp_ctx.SRP_give_srp_client_pwd_callback = ctx->srp_ctx.SRP_give_srp_client_pwd_callback;
143
144 s->srp_ctx.N = NULL;
145 s->srp_ctx.g = NULL;
146 s->srp_ctx.s = NULL;
147 s->srp_ctx.B = NULL;
148 s->srp_ctx.A = NULL;
149 s->srp_ctx.a = NULL;
150 s->srp_ctx.b = NULL;
151 s->srp_ctx.v = NULL;
152 s->srp_ctx.login = NULL;
153 s->srp_ctx.info = ctx->srp_ctx.info;
154 s->srp_ctx.strength = ctx->srp_ctx.strength;
155
156 if (((ctx->srp_ctx.N != NULL) &&
157 ((s->srp_ctx.N = BN_dup(ctx->srp_ctx.N)) == NULL)) ||
158 ((ctx->srp_ctx.g != NULL) &&
159 ((s->srp_ctx.g = BN_dup(ctx->srp_ctx.g)) == NULL)) ||
160 ((ctx->srp_ctx.s != NULL) &&
161 ((s->srp_ctx.s = BN_dup(ctx->srp_ctx.s)) == NULL)) ||
162 ((ctx->srp_ctx.B != NULL) &&
163 ((s->srp_ctx.B = BN_dup(ctx->srp_ctx.B)) == NULL)) ||
164 ((ctx->srp_ctx.A != NULL) &&
165 ((s->srp_ctx.A = BN_dup(ctx->srp_ctx.A)) == NULL)) ||
166 ((ctx->srp_ctx.a != NULL) &&
167 ((s->srp_ctx.a = BN_dup(ctx->srp_ctx.a)) == NULL)) ||
168 ((ctx->srp_ctx.v != NULL) &&
169 ((s->srp_ctx.v = BN_dup(ctx->srp_ctx.v)) == NULL)) ||
170 ((ctx->srp_ctx.b != NULL) &&
171 ((s->srp_ctx.b = BN_dup(ctx->srp_ctx.b)) == NULL)))
172 {
173 SSLerr(SSL_F_SSL_SRP_CTX_INIT,ERR_R_BN_LIB);
174 goto err;
175 }
176 if ((ctx->srp_ctx.login != NULL) &&
177 ((s->srp_ctx.login = BUF_strdup(ctx->srp_ctx.login)) == NULL))
178 {
179 SSLerr(SSL_F_SSL_SRP_CTX_INIT,ERR_R_INTERNAL_ERROR);
180 goto err;
181 }
182 s->srp_ctx.srp_Mask = ctx->srp_ctx.srp_Mask;
183
184 return (1);
185 err:
186 OPENSSL_free(s->srp_ctx.login);
187 BN_free(s->srp_ctx.N);
188 BN_free(s->srp_ctx.g);
189 BN_free(s->srp_ctx.s);
190 BN_free(s->srp_ctx.B);
191 BN_free(s->srp_ctx.A);
192 BN_free(s->srp_ctx.a);
193 BN_free(s->srp_ctx.b);
194 BN_free(s->srp_ctx.v);
195 return (0);
196 }
197
198 int SSL_CTX_SRP_CTX_init(struct ssl_ctx_st *ctx)
199 {
200 if (ctx == NULL)
201 return 0;
202
203 ctx->srp_ctx.SRP_cb_arg = NULL;
204 /* set client Hello login callback */
205 ctx->srp_ctx.TLS_ext_srp_username_callback = NULL;
206 /* set SRP N/g param callback for verification */
207 ctx->srp_ctx.SRP_verify_param_callback = NULL;
208 /* set SRP client passwd callback */
209 ctx->srp_ctx.SRP_give_srp_client_pwd_callback = NULL;
210
211 ctx->srp_ctx.N = NULL;
212 ctx->srp_ctx.g = NULL;
213 ctx->srp_ctx.s = NULL;
214 ctx->srp_ctx.B = NULL;
215 ctx->srp_ctx.A = NULL;
216 ctx->srp_ctx.a = NULL;
217 ctx->srp_ctx.b = NULL;
218 ctx->srp_ctx.v = NULL;
219 ctx->srp_ctx.login = NULL;
220 ctx->srp_ctx.srp_Mask = 0;
221 ctx->srp_ctx.info = NULL;
222 ctx->srp_ctx.strength = SRP_MINIMAL_N;
223
224 return (1);
225 }
226
227 /* server side */
228 int SSL_srp_server_param_with_username(SSL *s, int *ad)
229 {
230 unsigned char b[SSL_MAX_MASTER_KEY_LENGTH];
231 int al;
232
233 *ad = SSL_AD_UNKNOWN_PSK_IDENTITY;
234 if ((s->srp_ctx.TLS_ext_srp_username_callback !=NULL) &&
235 ((al = s->srp_ctx.TLS_ext_srp_username_callback(s, ad, s->srp_ctx.SRP_cb_arg))!=SSL_ERROR_NONE))
236 return al;
237
238 *ad = SSL_AD_INTERNAL_ERROR;
239 if ((s->srp_ctx.N == NULL) ||
240 (s->srp_ctx.g == NULL) ||
241 (s->srp_ctx.s == NULL) ||
242 (s->srp_ctx.v == NULL))
243 return SSL3_AL_FATAL;
244
245 if (RAND_bytes(b, sizeof(b)) <= 0)
246 return SSL3_AL_FATAL;
247 s->srp_ctx.b = BN_bin2bn(b,sizeof(b),NULL);
248 OPENSSL_cleanse(b,sizeof(b));
249
250 /* Calculate: B = (kv + g^b) % N */
251
252 return ((s->srp_ctx.B = SRP_Calc_B(s->srp_ctx.b, s->srp_ctx.N, s->srp_ctx.g, s->srp_ctx.v)) != NULL)?
253 SSL_ERROR_NONE:SSL3_AL_FATAL;
254 }
255
256 /* If the server just has the raw password, make up a verifier entry on the fly */
257 int SSL_set_srp_server_param_pw(SSL *s, const char *user, const char *pass, const char *grp)
258 {
259 SRP_gN *GN = SRP_get_default_gN(grp);
260 if(GN == NULL) return -1;
261 s->srp_ctx.N = BN_dup(GN->N);
262 s->srp_ctx.g = BN_dup(GN->g);
263 if(s->srp_ctx.v != NULL)
264 {
265 BN_clear_free(s->srp_ctx.v);
266 s->srp_ctx.v = NULL;
267 }
268 if(s->srp_ctx.s != NULL)
269 {
270 BN_clear_free(s->srp_ctx.s);
271 s->srp_ctx.s = NULL;
272 }
273 if(!SRP_create_verifier_BN(user, pass, &s->srp_ctx.s, &s->srp_ctx.v, GN->N, GN->g)) return -1;
274
275 return 1;
276 }
277
278 int SSL_set_srp_server_param(SSL *s, const BIGNUM *N, const BIGNUM *g,
279 BIGNUM *sa, BIGNUM *v, char *info)
280 {
281 if (N!= NULL)
282 {
283 if (s->srp_ctx.N != NULL)
284 {
285 if (!BN_copy(s->srp_ctx.N,N))
286 {
287 BN_free(s->srp_ctx.N);
288 s->srp_ctx.N = NULL;
289 }
290 }
291 else
292 s->srp_ctx.N = BN_dup(N);
293 }
294 if (g!= NULL)
295 {
296 if (s->srp_ctx.g != NULL)
297 {
298 if (!BN_copy(s->srp_ctx.g,g))
299 {
300 BN_free(s->srp_ctx.g);
301 s->srp_ctx.g = NULL;
302 }
303 }
304 else
305 s->srp_ctx.g = BN_dup(g);
306 }
307 if (sa!= NULL)
308 {
309 if (s->srp_ctx.s != NULL)
310 {
311 if (!BN_copy(s->srp_ctx.s,sa))
312 {
313 BN_free(s->srp_ctx.s);
314 s->srp_ctx.s = NULL;
315 }
316 }
317 else
318 s->srp_ctx.s = BN_dup(sa);
319 }
320 if (v!= NULL)
321 {
322 if (s->srp_ctx.v != NULL)
323 {
324 if (!BN_copy(s->srp_ctx.v,v))
325 {
326 BN_free(s->srp_ctx.v);
327 s->srp_ctx.v = NULL;
328 }
329 }
330 else
331 s->srp_ctx.v = BN_dup(v);
332 }
333 s->srp_ctx.info = info;
334
335 if (!(s->srp_ctx.N) ||
336 !(s->srp_ctx.g) ||
337 !(s->srp_ctx.s) ||
338 !(s->srp_ctx.v))
339 return -1;
340
341 return 1;
342 }
343
344 int SRP_generate_server_master_secret(SSL *s,unsigned char *master_key)
345 {
346 BIGNUM *K = NULL, *u = NULL;
347 int ret = -1, tmp_len;
348 unsigned char *tmp = NULL;
349
350 if (!SRP_Verify_A_mod_N(s->srp_ctx.A,s->srp_ctx.N))
351 goto err;
352 if (!(u = SRP_Calc_u(s->srp_ctx.A,s->srp_ctx.B,s->srp_ctx.N)))
353 goto err;
354 if (!(K = SRP_Calc_server_key(s->srp_ctx.A, s->srp_ctx.v, u, s->srp_ctx.b, s->srp_ctx.N)))
355 goto err;
356
357 tmp_len = BN_num_bytes(K);
358 if ((tmp = OPENSSL_malloc(tmp_len)) == NULL)
359 goto err;
360 BN_bn2bin(K, tmp);
361 ret = s->method->ssl3_enc->generate_master_secret(s,master_key,tmp,tmp_len);
362 err:
363 if (tmp)
364 {
365 OPENSSL_cleanse(tmp,tmp_len) ;
366 OPENSSL_free(tmp);
367 }
368 BN_clear_free(K);
369 BN_clear_free(u);
370 return ret;
371 }
372
373 /* client side */
374 int SRP_generate_client_master_secret(SSL *s,unsigned char *master_key)
375 {
376 BIGNUM *x = NULL, *u = NULL, *K = NULL;
377 int ret = -1, tmp_len;
378 char *passwd = NULL;
379 unsigned char *tmp = NULL;
380
381 /* Checks if b % n == 0
382 */
383 if (SRP_Verify_B_mod_N(s->srp_ctx.B,s->srp_ctx.N)==0) goto err;
384 if (!(u = SRP_Calc_u(s->srp_ctx.A,s->srp_ctx.B,s->srp_ctx.N))) goto err;
385 if (s->srp_ctx.SRP_give_srp_client_pwd_callback == NULL) goto err;
386 if (!(passwd = s->srp_ctx.SRP_give_srp_client_pwd_callback(s, s->srp_ctx.SRP_cb_arg))) goto err;
387 if (!(x = SRP_Calc_x(s->srp_ctx.s,s->srp_ctx.login,passwd))) goto err;
388 if (!(K = SRP_Calc_client_key(s->srp_ctx.N, s->srp_ctx.B, s->srp_ctx.g, x, s->srp_ctx.a, u))) goto err;
389
390 tmp_len = BN_num_bytes(K);
391 if ((tmp = OPENSSL_malloc(tmp_len)) == NULL) goto err;
392 BN_bn2bin(K, tmp);
393 ret = s->method->ssl3_enc->generate_master_secret(s,master_key,tmp,tmp_len);
394 err:
395 if (tmp)
396 {
397 OPENSSL_cleanse(tmp,tmp_len) ;
398 OPENSSL_free(tmp);
399 }
400 BN_clear_free(K);
401 BN_clear_free(x);
402 if (passwd)
403 {
404 OPENSSL_cleanse(passwd,strlen(passwd)) ;
405 OPENSSL_free(passwd);
406 }
407 BN_clear_free(u);
408 return ret;
409 }
410
411 int srp_verify_server_param(SSL *s, int *al)
412 {
413 SRP_CTX *srp = &s->srp_ctx;
414 /* Sanity check parameters: we can quickly check B % N == 0
415 * by checking B != 0 since B < N
416 */
417 if (BN_ucmp(srp->g, srp->N) >=0 || BN_ucmp(srp->B, srp->N) >= 0
418 || BN_is_zero(srp->B))
419 {
420 *al = SSL3_AD_ILLEGAL_PARAMETER;
421 return 0;
422 }
423
424 if (BN_num_bits(srp->N) < srp->strength)
425 {
426 *al = TLS1_AD_INSUFFICIENT_SECURITY;
427 return 0;
428 }
429
430 if (srp->SRP_verify_param_callback)
431 {
432 if (srp->SRP_verify_param_callback(s, srp->SRP_cb_arg) <= 0)
433 {
434 *al = TLS1_AD_INSUFFICIENT_SECURITY;
435 return 0;
436 }
437 }
438 else if(!SRP_check_known_gN_param(srp->g, srp->N))
439 {
440 *al = TLS1_AD_INSUFFICIENT_SECURITY;
441 return 0;
442 }
443
444 return 1;
445 }
446
447
448 int SRP_Calc_A_param(SSL *s)
449 {
450 unsigned char rnd[SSL_MAX_MASTER_KEY_LENGTH];
451
452 RAND_bytes(rnd, sizeof(rnd));
453 s->srp_ctx.a = BN_bin2bn(rnd, sizeof(rnd), s->srp_ctx.a);
454 OPENSSL_cleanse(rnd, sizeof(rnd));
455
456 if (!(s->srp_ctx.A = SRP_Calc_A(s->srp_ctx.a,s->srp_ctx.N,s->srp_ctx.g)))
457 return -1;
458
459 return 1;
460 }
461
462 BIGNUM *SSL_get_srp_g(SSL *s)
463 {
464 if (s->srp_ctx.g != NULL)
465 return s->srp_ctx.g;
466 return s->ctx->srp_ctx.g;
467 }
468
469 BIGNUM *SSL_get_srp_N(SSL *s)
470 {
471 if (s->srp_ctx.N != NULL)
472 return s->srp_ctx.N;
473 return s->ctx->srp_ctx.N;
474 }
475
476 char *SSL_get_srp_username(SSL *s)
477 {
478 if (s->srp_ctx.login != NULL)
479 return s->srp_ctx.login;
480 return s->ctx->srp_ctx.login;
481 }
482
483 char *SSL_get_srp_userinfo(SSL *s)
484 {
485 if (s->srp_ctx.info != NULL)
486 return s->srp_ctx.info;
487 return s->ctx->srp_ctx.info;
488 }
489
490 #define tls1_ctx_ctrl ssl3_ctx_ctrl
491 #define tls1_ctx_callback_ctrl ssl3_ctx_callback_ctrl
492
493 int SSL_CTX_set_srp_username(SSL_CTX *ctx,char *name)
494 {
495 return tls1_ctx_ctrl(ctx,SSL_CTRL_SET_TLS_EXT_SRP_USERNAME,0,name);
496 }
497
498 int SSL_CTX_set_srp_password(SSL_CTX *ctx,char *password)
499 {
500 return tls1_ctx_ctrl(ctx,SSL_CTRL_SET_TLS_EXT_SRP_PASSWORD,0,password);
501 }
502
503 int SSL_CTX_set_srp_strength(SSL_CTX *ctx, int strength)
504 {
505 return tls1_ctx_ctrl(ctx, SSL_CTRL_SET_TLS_EXT_SRP_STRENGTH, strength,
506 NULL);
507 }
508
509 int SSL_CTX_set_srp_verify_param_callback(SSL_CTX *ctx, int (*cb)(SSL *,void *))
510 {
511 return tls1_ctx_callback_ctrl(ctx,SSL_CTRL_SET_SRP_VERIFY_PARAM_CB,
512 (void (*)(void))cb);
513 }
514
515 int SSL_CTX_set_srp_cb_arg(SSL_CTX *ctx, void *arg)
516 {
517 return tls1_ctx_ctrl(ctx,SSL_CTRL_SET_SRP_ARG,0,arg);
518 }
519
520 int SSL_CTX_set_srp_username_callback(SSL_CTX *ctx,
521 int (*cb)(SSL *,int *,void *))
522 {
523 return tls1_ctx_callback_ctrl(ctx,SSL_CTRL_SET_TLS_EXT_SRP_USERNAME_CB,
524 (void (*)(void))cb);
525 }
526
527 int SSL_CTX_set_srp_client_pwd_callback(SSL_CTX *ctx, char *(*cb)(SSL *,void *))
528 {
529 return tls1_ctx_callback_ctrl(ctx,SSL_CTRL_SET_SRP_GIVE_CLIENT_PWD_CB,
530 (void (*)(void))cb);
531 }
532
533 #endif