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tls_srp.c
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1 /* ssl/tls_srp.c */
2 /* Written by Christophe Renou ([email protected]) with
3  * the precious help of Peter Sylvester ([email protected])
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.
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11  * are met:
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14  * notice, this list of conditions and the following disclaimer.
15  *
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17  * notice, this list of conditions and the following disclaimer in
18  * the documentation and/or other materials provided with the
19  * distribution.
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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/)"
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36  * acknowledgment:
37  * "This product includes software developed by the OpenSSL Project
38  * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
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40  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
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49  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
50  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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53  *
54  * This product includes cryptographic software written by Eric Young
55  * ([email protected]). This product includes software written by Tim
56  * Hudson ([email protected]).
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  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 */
256 int 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 
277 int 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 
343 int 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);
361 err:
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 */
373 int 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);
393 err:
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 
410 int 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 
435 BIGNUM *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 
442 BIGNUM *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 
449 char *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 
456 char *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 
466 int 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 
471 int 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 
476 int 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 
482 int 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 
488 int 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 
493 int 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 
500 int 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
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