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
66int 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
98int 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
130int 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);
185err:
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
198int 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 */
228int 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	RAND_bytes(b, sizeof(b));
246	s->srp_ctx.b = BN_bin2bn(b,sizeof(b),NULL);
247	OPENSSL_cleanse(b,sizeof(b));
248
249	/* Calculate:  B = (kv + g^b) % N  */
250
251	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)?
252			SSL_ERROR_NONE:SSL3_AL_FATAL;
253	}
254
255/* If the server just has the raw password, make up a verifier entry on the fly */
256int SSL_set_srp_server_param_pw(SSL *s, const char *user, const char *pass, const char *grp)
257	{
258	SRP_gN *GN = SRP_get_default_gN(grp);
259	if(GN == NULL) return -1;
260	s->srp_ctx.N = BN_dup(GN->N);
261	s->srp_ctx.g = BN_dup(GN->g);
262	if(s->srp_ctx.v != NULL)
263		{
264		BN_clear_free(s->srp_ctx.v);
265		s->srp_ctx.v = NULL;
266		}
267	if(s->srp_ctx.s != NULL)
268		{
269		BN_clear_free(s->srp_ctx.s);
270		s->srp_ctx.s = NULL;
271		}
272	if(!SRP_create_verifier_BN(user, pass, &s->srp_ctx.s, &s->srp_ctx.v, GN->N, GN->g)) return -1;
273
274	return 1;
275	}
276
277int SSL_set_srp_server_param(SSL *s, const BIGNUM *N, const BIGNUM *g,
278			     BIGNUM *sa, BIGNUM *v, char *info)
279	{
280	if (N!= NULL)
281		{
282		if (s->srp_ctx.N != NULL)
283			{
284			if (!BN_copy(s->srp_ctx.N,N))
285				{
286				BN_free(s->srp_ctx.N);
287				s->srp_ctx.N = NULL;
288				}
289			}
290		else
291			s->srp_ctx.N = BN_dup(N);
292		}
293	if (g!= NULL)
294		{
295		if (s->srp_ctx.g != NULL)
296			{
297			if (!BN_copy(s->srp_ctx.g,g))
298				{
299				BN_free(s->srp_ctx.g);
300				s->srp_ctx.g = NULL;
301				}
302			}
303		else
304			s->srp_ctx.g = BN_dup(g);
305		}
306	if (sa!= NULL)
307		{
308		if (s->srp_ctx.s != NULL)
309			{
310			if (!BN_copy(s->srp_ctx.s,sa))
311				{
312				BN_free(s->srp_ctx.s);
313				s->srp_ctx.s = NULL;
314				}
315			}
316		else
317			s->srp_ctx.s = BN_dup(sa);
318		}
319	if (v!= NULL)
320		{
321		if (s->srp_ctx.v != NULL)
322			{
323			if (!BN_copy(s->srp_ctx.v,v))
324				{
325				BN_free(s->srp_ctx.v);
326				s->srp_ctx.v = NULL;
327				}
328			}
329		else
330			s->srp_ctx.v = BN_dup(v);
331		}
332	s->srp_ctx.info = info;
333
334	if (!(s->srp_ctx.N) ||
335		!(s->srp_ctx.g) ||
336		!(s->srp_ctx.s) ||
337		!(s->srp_ctx.v))
338		return -1;
339
340	return 1;
341	}
342
343int SRP_generate_server_master_secret(SSL *s,unsigned char *master_key)
344	{
345	BIGNUM *K = NULL, *u = NULL;
346	int ret = -1, tmp_len;
347	unsigned char *tmp = NULL;
348
349	if (!SRP_Verify_A_mod_N(s->srp_ctx.A,s->srp_ctx.N))
350		goto err;
351	if (!(u = SRP_Calc_u(s->srp_ctx.A,s->srp_ctx.B,s->srp_ctx.N)))
352		goto err;
353	if (!(K = SRP_Calc_server_key(s->srp_ctx.A, s->srp_ctx.v, u, s->srp_ctx.b, s->srp_ctx.N)))
354		goto err;
355
356	tmp_len = BN_num_bytes(K);
357	if ((tmp = OPENSSL_malloc(tmp_len)) == NULL)
358		goto err;
359	BN_bn2bin(K, tmp);
360	ret = s->method->ssl3_enc->generate_master_secret(s,master_key,tmp,tmp_len);
361err:
362	if (tmp)
363		{
364		OPENSSL_cleanse(tmp,tmp_len) ;
365		OPENSSL_free(tmp);
366		}
367	BN_clear_free(K);
368	BN_clear_free(u);
369	return ret;
370	}
371
372/* client side */
373int SRP_generate_client_master_secret(SSL *s,unsigned char *master_key)
374	{
375	BIGNUM *x = NULL, *u = NULL, *K = NULL;
376	int ret = -1, tmp_len;
377	char *passwd = NULL;
378	unsigned char *tmp = NULL;
379
380	/* Checks if b % n == 0
381	 */
382	if (SRP_Verify_B_mod_N(s->srp_ctx.B,s->srp_ctx.N)==0) goto err;
383	if (!(u = SRP_Calc_u(s->srp_ctx.A,s->srp_ctx.B,s->srp_ctx.N))) goto err;
384	if (s->srp_ctx.SRP_give_srp_client_pwd_callback == NULL) goto err;
385	if (!(passwd = s->srp_ctx.SRP_give_srp_client_pwd_callback(s, s->srp_ctx.SRP_cb_arg))) goto err;
386	if (!(x = SRP_Calc_x(s->srp_ctx.s,s->srp_ctx.login,passwd))) goto err;
387	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;
388
389	tmp_len = BN_num_bytes(K);
390	if ((tmp = OPENSSL_malloc(tmp_len)) == NULL) goto err;
391	BN_bn2bin(K, tmp);
392	ret = s->method->ssl3_enc->generate_master_secret(s,master_key,tmp,tmp_len);
393err:
394	if (tmp)
395		{
396		OPENSSL_cleanse(tmp,tmp_len) ;
397		OPENSSL_free(tmp);
398		}
399	BN_clear_free(K);
400	BN_clear_free(x);
401	if (passwd)
402		{
403		OPENSSL_cleanse(passwd,strlen(passwd)) ;
404		OPENSSL_free(passwd);
405		}
406	BN_clear_free(u);
407	return ret;
408	}
409
410int SRP_Calc_A_param(SSL *s)
411	{
412	unsigned char rnd[SSL_MAX_MASTER_KEY_LENGTH];
413
414	if (BN_num_bits(s->srp_ctx.N) < s->srp_ctx.strength)
415		return -1;
416
417	if (s->srp_ctx.SRP_verify_param_callback ==NULL &&
418		!SRP_check_known_gN_param(s->srp_ctx.g,s->srp_ctx.N))
419		return -1 ;
420
421	RAND_bytes(rnd, sizeof(rnd));
422	s->srp_ctx.a = BN_bin2bn(rnd, sizeof(rnd), s->srp_ctx.a);
423	OPENSSL_cleanse(rnd, sizeof(rnd));
424
425	if (!(s->srp_ctx.A = SRP_Calc_A(s->srp_ctx.a,s->srp_ctx.N,s->srp_ctx.g)))
426		return -1;
427
428	/* We can have a callback to verify SRP param!! */
429	if (s->srp_ctx.SRP_verify_param_callback !=NULL)
430		return s->srp_ctx.SRP_verify_param_callback(s,s->srp_ctx.SRP_cb_arg);
431
432	return 1;
433	}
434
435BIGNUM *SSL_get_srp_g(SSL *s)
436	{
437	if (s->srp_ctx.g != NULL)
438		return s->srp_ctx.g;
439	return s->ctx->srp_ctx.g;
440	}
441
442BIGNUM *SSL_get_srp_N(SSL *s)
443	{
444	if (s->srp_ctx.N != NULL)
445		return s->srp_ctx.N;
446	return s->ctx->srp_ctx.N;
447	}
448
449char *SSL_get_srp_username(SSL *s)
450	{
451	if (s->srp_ctx.login != NULL)
452		return s->srp_ctx.login;
453	return s->ctx->srp_ctx.login;
454	}
455
456char *SSL_get_srp_userinfo(SSL *s)
457	{
458	if (s->srp_ctx.info != NULL)
459		return s->srp_ctx.info;
460	return s->ctx->srp_ctx.info;
461	}
462
463#define tls1_ctx_ctrl ssl3_ctx_ctrl
464#define tls1_ctx_callback_ctrl ssl3_ctx_callback_ctrl
465
466int SSL_CTX_set_srp_username(SSL_CTX *ctx,char *name)
467	{
468	return tls1_ctx_ctrl(ctx,SSL_CTRL_SET_TLS_EXT_SRP_USERNAME,0,name);
469	}
470
471int SSL_CTX_set_srp_password(SSL_CTX *ctx,char *password)
472	{
473	return tls1_ctx_ctrl(ctx,SSL_CTRL_SET_TLS_EXT_SRP_PASSWORD,0,password);
474	}
475
476int SSL_CTX_set_srp_strength(SSL_CTX *ctx, int strength)
477	{
478	return tls1_ctx_ctrl(ctx, SSL_CTRL_SET_TLS_EXT_SRP_STRENGTH, strength,
479			     NULL);
480	}
481
482int SSL_CTX_set_srp_verify_param_callback(SSL_CTX *ctx, int (*cb)(SSL *,void *))
483	{
484	return tls1_ctx_callback_ctrl(ctx,SSL_CTRL_SET_SRP_VERIFY_PARAM_CB,
485				      (void (*)(void))cb);
486	}
487
488int SSL_CTX_set_srp_cb_arg(SSL_CTX *ctx, void *arg)
489	{
490	return tls1_ctx_ctrl(ctx,SSL_CTRL_SET_SRP_ARG,0,arg);
491	}
492
493int SSL_CTX_set_srp_username_callback(SSL_CTX *ctx,
494				      int (*cb)(SSL *,int *,void *))
495	{
496	return tls1_ctx_callback_ctrl(ctx,SSL_CTRL_SET_TLS_EXT_SRP_USERNAME_CB,
497				      (void (*)(void))cb);
498	}
499
500int SSL_CTX_set_srp_client_pwd_callback(SSL_CTX *ctx, char *(*cb)(SSL *,void *))
501	{
502	return tls1_ctx_callback_ctrl(ctx,SSL_CTRL_SET_SRP_GIVE_CLIENT_PWD_CB,
503				      (void (*)(void))cb);
504	}
505
506#endif
507