1 /* crypto/srp/srp_lib.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 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 #ifndef OPENSSL_NO_SRP
60 #include "cryptlib.h"
61 #include "srp_lcl.h"
62 #include <openssl/srp.h>
63 #include <openssl/evp.h>
64
65 #if (BN_BYTES == 8)
66 # if (defined(_WIN32) || defined(_WIN64)) && !defined(__MINGW32__)
67 # define bn_pack4(a1,a2,a3,a4) ((a1##UI64<<48)|(a2##UI64<<32)|(a3##UI64<<16)|a4##UI64)
68 # elif defined(__arch64__)
69 # define bn_pack4(a1,a2,a3,a4) ((a1##UL<<48)|(a2##UL<<32)|(a3##UL<<16)|a4##UL)
70 # else
71 # define bn_pack4(a1,a2,a3,a4) ((a1##ULL<<48)|(a2##ULL<<32)|(a3##ULL<<16)|a4##ULL)
72 # endif
73 #elif (BN_BYTES == 4)
74 # define bn_pack4(a1,a2,a3,a4) ((a3##UL<<16)|a4##UL), ((a1##UL<<16)|a2##UL)
75 #else
76 # error "unsupported BN_BYTES"
77 #endif
78
79
80 #include "srp_grps.h"
81
82 static BIGNUM *srp_Calc_k(BIGNUM *N, BIGNUM *g)
83 {
84 /* k = SHA1(N | PAD(g)) -- tls-srp draft 8 */
85
86 unsigned char digest[SHA_DIGEST_LENGTH];
87 unsigned char *tmp;
88 EVP_MD_CTX ctxt;
89 int longg ;
90 int longN = BN_num_bytes(N);
91
92 if (BN_ucmp(g, N) >= 0)
93 return NULL;
94
95 if ((tmp = OPENSSL_malloc(longN)) == NULL)
96 return NULL;
97 BN_bn2bin(N,tmp) ;
98
99 EVP_MD_CTX_init(&ctxt);
100 EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL);
101 EVP_DigestUpdate(&ctxt, tmp, longN);
102
103 memset(tmp, 0, longN);
104 longg = BN_bn2bin(g,tmp) ;
105 /* use the zeros behind to pad on left */
106 EVP_DigestUpdate(&ctxt, tmp + longg, longN-longg);
107 EVP_DigestUpdate(&ctxt, tmp, longg);
108 OPENSSL_free(tmp);
109
110 EVP_DigestFinal_ex(&ctxt, digest, NULL);
111 EVP_MD_CTX_cleanup(&ctxt);
112 return BN_bin2bn(digest, sizeof(digest), NULL);
113 }
114
115 BIGNUM *SRP_Calc_u(BIGNUM *A, BIGNUM *B, BIGNUM *N)
116 {
117 /* k = SHA1(PAD(A) || PAD(B) ) -- tls-srp draft 8 */
118
119 BIGNUM *u;
120 unsigned char cu[SHA_DIGEST_LENGTH];
121 unsigned char *cAB;
122 EVP_MD_CTX ctxt;
123 int longN;
124 if ((A == NULL) ||(B == NULL) || (N == NULL))
125 return NULL;
126
127 if (BN_ucmp(A, N) >= 0 || BN_ucmp(B, N) >= 0)
128 return NULL;
129
130 longN= BN_num_bytes(N);
131
132 if ((cAB = OPENSSL_malloc(2*longN)) == NULL)
133 return NULL;
134
135 memset(cAB, 0, longN);
136
137 EVP_MD_CTX_init(&ctxt);
138 EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL);
139 EVP_DigestUpdate(&ctxt, cAB + BN_bn2bin(A,cAB+longN), longN);
140 EVP_DigestUpdate(&ctxt, cAB + BN_bn2bin(B,cAB+longN), longN);
141 OPENSSL_free(cAB);
142 EVP_DigestFinal_ex(&ctxt, cu, NULL);
143 EVP_MD_CTX_cleanup(&ctxt);
144
145 if (!(u = BN_bin2bn(cu, sizeof(cu), NULL)))
146 return NULL;
147 if (!BN_is_zero(u))
148 return u;
149 BN_free(u);
150 return NULL;
151 }
152
153 BIGNUM *SRP_Calc_server_key(BIGNUM *A, BIGNUM *v, BIGNUM *u, BIGNUM *b, BIGNUM *N)
154 {
155 BIGNUM *tmp = NULL, *S = NULL;
156 BN_CTX *bn_ctx;
157
158 if (u == NULL || A == NULL || v == NULL || b == NULL || N == NULL)
159 return NULL;
160
161 if ((bn_ctx = BN_CTX_new()) == NULL ||
162 (tmp = BN_new()) == NULL ||
163 (S = BN_new()) == NULL )
164 goto err;
165
166 /* S = (A*v**u) ** b */
167
168 if (!BN_mod_exp(tmp,v,u,N,bn_ctx))
169 goto err;
170 if (!BN_mod_mul(tmp,A,tmp,N,bn_ctx))
171 goto err;
172 if (!BN_mod_exp(S,tmp,b,N,bn_ctx))
173 goto err;
174 err:
175 BN_CTX_free(bn_ctx);
176 BN_clear_free(tmp);
177 return S;
178 }
179
180 BIGNUM *SRP_Calc_B(BIGNUM *b, BIGNUM *N, BIGNUM *g, BIGNUM *v)
181 {
182 BIGNUM *kv = NULL, *gb = NULL;
183 BIGNUM *B = NULL, *k = NULL;
184 BN_CTX *bn_ctx;
185
186 if (b == NULL || N == NULL || g == NULL || v == NULL ||
187 (bn_ctx = BN_CTX_new()) == NULL)
188 return NULL;
189
190 if ( (kv = BN_new()) == NULL ||
191 (gb = BN_new()) == NULL ||
192 (B = BN_new())== NULL)
193 goto err;
194
195 /* B = g**b + k*v */
196
197 if (!BN_mod_exp(gb,g,b,N,bn_ctx) ||
198 !(k = srp_Calc_k(N,g)) ||
199 !BN_mod_mul(kv,v,k,N,bn_ctx) ||
200 !BN_mod_add(B,gb,kv,N,bn_ctx))
201 {
202 BN_free(B);
203 B = NULL;
204 }
205 err:
206 BN_CTX_free(bn_ctx);
207 BN_clear_free(kv);
208 BN_clear_free(gb);
209 BN_free(k);
210 return B;
211 }
212
213 BIGNUM *SRP_Calc_x(BIGNUM *s, const char *user, const char *pass)
214 {
215 unsigned char dig[SHA_DIGEST_LENGTH];
216 EVP_MD_CTX ctxt;
217 unsigned char *cs;
218
219 if ((s == NULL) ||
220 (user == NULL) ||
221 (pass == NULL))
222 return NULL;
223
224 if ((cs = OPENSSL_malloc(BN_num_bytes(s))) == NULL)
225 return NULL;
226
227 EVP_MD_CTX_init(&ctxt);
228 EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL);
229 EVP_DigestUpdate(&ctxt, user, strlen(user));
230 EVP_DigestUpdate(&ctxt, ":", 1);
231 EVP_DigestUpdate(&ctxt, pass, strlen(pass));
232 EVP_DigestFinal_ex(&ctxt, dig, NULL);
233
234 EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL);
235 BN_bn2bin(s,cs);
236 EVP_DigestUpdate(&ctxt, cs, BN_num_bytes(s));
237 OPENSSL_free(cs);
238 EVP_DigestUpdate(&ctxt, dig, sizeof(dig));
239 EVP_DigestFinal_ex(&ctxt, dig, NULL);
240 EVP_MD_CTX_cleanup(&ctxt);
241
242 return BN_bin2bn(dig, sizeof(dig), NULL);
243 }
244
245 BIGNUM *SRP_Calc_A(BIGNUM *a, BIGNUM *N, BIGNUM *g)
246 {
247 BN_CTX *bn_ctx;
248 BIGNUM * A = NULL;
249
250 if (a == NULL || N == NULL || g == NULL ||
251 (bn_ctx = BN_CTX_new()) == NULL)
252 return NULL;
253
254 if ((A = BN_new()) != NULL &&
255 !BN_mod_exp(A,g,a,N,bn_ctx))
256 {
257 BN_free(A);
258 A = NULL;
259 }
260 BN_CTX_free(bn_ctx);
261 return A;
262 }
263
264
265 BIGNUM *SRP_Calc_client_key(BIGNUM *N, BIGNUM *B, BIGNUM *g, BIGNUM *x, BIGNUM *a, BIGNUM *u)
266 {
267 BIGNUM *tmp = NULL, *tmp2 = NULL, *tmp3 = NULL , *k = NULL, *K = NULL;
268 BN_CTX *bn_ctx;
269
270 if (u == NULL || B == NULL || N == NULL || g == NULL || x == NULL || a == NULL ||
271 (bn_ctx = BN_CTX_new()) == NULL)
272 return NULL;
273
274 if ((tmp = BN_new()) == NULL ||
275 (tmp2 = BN_new())== NULL ||
276 (tmp3 = BN_new())== NULL ||
277 (K = BN_new()) == NULL)
278 goto err;
279
280 if (!BN_mod_exp(tmp,g,x,N,bn_ctx))
281 goto err;
282 if (!(k = srp_Calc_k(N,g)))
283 goto err;
284 if (!BN_mod_mul(tmp2,tmp,k,N,bn_ctx))
285 goto err;
286 if (!BN_mod_sub(tmp,B,tmp2,N,bn_ctx))
287 goto err;
288
289 if (!BN_mod_mul(tmp3,u,x,N,bn_ctx))
290 goto err;
291 if (!BN_mod_add(tmp2,a,tmp3,N,bn_ctx))
292 goto err;
293 if (!BN_mod_exp(K,tmp,tmp2,N,bn_ctx))
294 goto err;
295
296 err :
297 BN_CTX_free(bn_ctx);
298 BN_clear_free(tmp);
299 BN_clear_free(tmp2);
300 BN_clear_free(tmp3);
301 BN_free(k);
302 return K;
303 }
304
305 int SRP_Verify_B_mod_N(BIGNUM *B, BIGNUM *N)
306 {
307 BIGNUM *r;
308 BN_CTX *bn_ctx;
309 int ret = 0;
310
311 if (B == NULL || N == NULL ||
312 (bn_ctx = BN_CTX_new()) == NULL)
313 return 0;
314
315 if ((r = BN_new()) == NULL)
316 goto err;
317 /* Checks if B % N == 0 */
318 if (!BN_nnmod(r,B,N,bn_ctx))
319 goto err;
320 ret = !BN_is_zero(r);
321 err:
322 BN_CTX_free(bn_ctx);
323 BN_free(r);
324 return ret;
325 }
326
327 int SRP_Verify_A_mod_N(BIGNUM *A, BIGNUM *N)
328 {
329 /* Checks if A % N == 0 */
330 return SRP_Verify_B_mod_N(A,N) ;
331 }
332
333
334 /* Check if G and N are kwown parameters.
335 The values have been generated from the ietf-tls-srp draft version 8
336 */
337 char *SRP_check_known_gN_param(BIGNUM *g, BIGNUM *N)
338 {
339 size_t i;
340 if ((g == NULL) || (N == NULL))
341 return 0;
342
343 srp_bn_print(g);
344 srp_bn_print(N);
345
346 for(i = 0; i < KNOWN_GN_NUMBER; i++)
347 {
348 if (BN_cmp(knowngN[i].g, g) == 0 && BN_cmp(knowngN[i].N, N) == 0)
349 return knowngN[i].id;
350 }
351 return NULL;
352 }
353
354 SRP_gN *SRP_get_default_gN(const char *id)
355 {
356 size_t i;
357
358 if (id == NULL)
359 return knowngN;
360 for(i = 0; i < KNOWN_GN_NUMBER; i++)
361 {
362 if (strcmp(knowngN[i].id, id)==0)
363 return knowngN + i;
364 }
365 return NULL;
366 }
367 #endif