]>
Commit | Line | Data |
---|---|---|
edc032b5 BL |
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 | #define bn_pack4(a1,a2,a3,a4) 0x##a1##a2##a3##a4##ul | |
67 | #endif | |
68 | #if (BN_BYTES == 4) | |
69 | #define bn_pack4(a1,a2,a3,a4) 0x##a3##a4##ul, 0x##a1##a2##ul | |
70 | #endif | |
71 | #if (BN_BYTES == 2) | |
72 | #define bn_pack4(a1,a2,a3,a4) 0x##a4##u,0x##a3##u,0x##a2##u,0x##a1##u | |
73 | #endif | |
74 | ||
75 | ||
76 | #include "srp_grps.h" | |
77 | ||
78 | static BIGNUM *srp_Calc_k(BIGNUM *N, BIGNUM *g) | |
79 | { | |
80 | /* k = SHA1(N | PAD(g)) -- tls-srp draft 8 */ | |
81 | ||
82 | unsigned char digest[SHA_DIGEST_LENGTH]; | |
83 | unsigned char *tmp; | |
84 | EVP_MD_CTX ctxt; | |
85 | int longg ; | |
86 | int longN = BN_num_bytes(N); | |
87 | ||
88 | if ((tmp = OPENSSL_malloc(longN)) == NULL) | |
89 | return NULL; | |
90 | BN_bn2bin(N,tmp) ; | |
91 | ||
92 | EVP_MD_CTX_init(&ctxt); | |
93 | EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL); | |
94 | EVP_DigestUpdate(&ctxt, tmp, longN); | |
95 | ||
96 | memset(tmp, 0, longN); | |
97 | longg = BN_bn2bin(g,tmp) ; | |
98 | /* use the zeros behind to pad on left */ | |
99 | EVP_DigestUpdate(&ctxt, tmp + longg, longN-longg); | |
100 | EVP_DigestUpdate(&ctxt, tmp, longg); | |
101 | OPENSSL_free(tmp); | |
102 | ||
103 | EVP_DigestFinal_ex(&ctxt, digest, NULL); | |
104 | EVP_MD_CTX_cleanup(&ctxt); | |
105 | return BN_bin2bn(digest, sizeof(digest), NULL); | |
106 | } | |
107 | ||
108 | BIGNUM *SRP_Calc_u(BIGNUM *A, BIGNUM *B, BIGNUM *N) | |
109 | { | |
110 | /* k = SHA1(PAD(A) || PAD(B) ) -- tls-srp draft 8 */ | |
111 | ||
112 | BIGNUM *u; | |
113 | unsigned char cu[SHA_DIGEST_LENGTH]; | |
114 | unsigned char *cAB; | |
115 | EVP_MD_CTX ctxt; | |
116 | int longN; | |
117 | if ((A == NULL) ||(B == NULL) || (N == NULL)) | |
118 | return NULL; | |
119 | ||
120 | longN= BN_num_bytes(N); | |
121 | ||
122 | if ((cAB = OPENSSL_malloc(2*longN)) == NULL) | |
123 | return NULL; | |
124 | ||
125 | memset(cAB, 0, longN); | |
126 | ||
127 | EVP_MD_CTX_init(&ctxt); | |
128 | EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL); | |
129 | EVP_DigestUpdate(&ctxt, cAB + BN_bn2bin(A,cAB+longN), longN); | |
130 | EVP_DigestUpdate(&ctxt, cAB + BN_bn2bin(B,cAB+longN), longN); | |
131 | OPENSSL_free(cAB); | |
132 | EVP_DigestFinal_ex(&ctxt, cu, NULL); | |
133 | EVP_MD_CTX_cleanup(&ctxt); | |
134 | ||
135 | if (!(u = BN_bin2bn(cu, sizeof(cu), NULL))) | |
136 | return NULL; | |
137 | if (!BN_is_zero(u)) | |
138 | return u; | |
139 | BN_free(u); | |
140 | return NULL; | |
141 | } | |
142 | ||
143 | BIGNUM *SRP_Calc_server_key(BIGNUM *A, BIGNUM *v, BIGNUM *u, BIGNUM *b, BIGNUM *N) | |
144 | { | |
145 | BIGNUM *tmp = NULL, *S = NULL; | |
146 | BN_CTX *bn_ctx; | |
147 | ||
148 | if (u == NULL || A == NULL || v == NULL || b == NULL || N == NULL) | |
149 | return NULL; | |
150 | ||
151 | if ((bn_ctx = BN_CTX_new()) == NULL || | |
152 | (tmp = BN_new()) == NULL || | |
153 | (S = BN_new()) == NULL ) | |
154 | goto err; | |
155 | ||
156 | /* S = (A*v**u) ** b */ | |
157 | ||
158 | if (!BN_mod_exp(tmp,v,u,N,bn_ctx)) | |
159 | goto err; | |
160 | if (!BN_mod_mul(tmp,A,tmp,N,bn_ctx)) | |
161 | goto err; | |
162 | if (!BN_mod_exp(S,tmp,b,N,bn_ctx)) | |
163 | goto err; | |
164 | err: | |
165 | BN_CTX_free(bn_ctx); | |
166 | BN_clear_free(tmp); | |
167 | return S; | |
168 | } | |
169 | ||
170 | BIGNUM *SRP_Calc_B(BIGNUM *b, BIGNUM *N, BIGNUM *g, BIGNUM *v) | |
171 | { | |
172 | BIGNUM *kv = NULL, *gb = NULL; | |
173 | BIGNUM *B = NULL, *k = NULL; | |
174 | BN_CTX *bn_ctx; | |
175 | ||
176 | if (b == NULL || N == NULL || g == NULL || v == NULL || | |
177 | (bn_ctx = BN_CTX_new()) == NULL) | |
178 | return NULL; | |
179 | ||
180 | if ( (kv = BN_new()) == NULL || | |
181 | (gb = BN_new()) == NULL || | |
182 | (B = BN_new())== NULL) | |
183 | goto err; | |
184 | ||
185 | /* B = g**b + k*v */ | |
186 | ||
187 | if (!BN_mod_exp(gb,g,b,N,bn_ctx) || | |
188 | !(k = srp_Calc_k(N,g)) || | |
189 | !BN_mod_mul(kv,v,k,N,bn_ctx) || | |
190 | !BN_mod_add(B,gb,kv,N,bn_ctx)) | |
191 | { | |
192 | BN_free(B); | |
193 | B = NULL; | |
194 | } | |
195 | err: | |
196 | BN_CTX_free(bn_ctx); | |
197 | BN_clear_free(kv); | |
198 | BN_clear_free(gb); | |
199 | BN_free(k); | |
200 | return B; | |
201 | } | |
202 | ||
203 | BIGNUM *SRP_Calc_x(BIGNUM *s, const char *user, const char *pass) | |
204 | { | |
205 | unsigned char dig[SHA_DIGEST_LENGTH]; | |
206 | EVP_MD_CTX ctxt; | |
207 | unsigned char *cs; | |
208 | ||
209 | if ((s == NULL) || | |
210 | (user == NULL) || | |
211 | (pass == NULL)) | |
212 | return NULL; | |
213 | ||
214 | if ((cs = OPENSSL_malloc(BN_num_bytes(s))) == NULL) | |
215 | return NULL; | |
216 | ||
217 | EVP_MD_CTX_init(&ctxt); | |
218 | EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL); | |
219 | EVP_DigestUpdate(&ctxt, user, strlen(user)); | |
220 | EVP_DigestUpdate(&ctxt, ":", 1); | |
221 | EVP_DigestUpdate(&ctxt, pass, strlen(pass)); | |
222 | EVP_DigestFinal_ex(&ctxt, dig, NULL); | |
223 | ||
224 | EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL); | |
225 | BN_bn2bin(s,cs); | |
226 | EVP_DigestUpdate(&ctxt, cs, BN_num_bytes(s)); | |
227 | OPENSSL_free(cs); | |
228 | EVP_DigestUpdate(&ctxt, dig, sizeof(dig)); | |
229 | EVP_DigestFinal_ex(&ctxt, dig, NULL); | |
230 | EVP_MD_CTX_cleanup(&ctxt); | |
231 | ||
232 | return BN_bin2bn(dig, sizeof(dig), NULL); | |
233 | } | |
234 | ||
235 | BIGNUM *SRP_Calc_A(BIGNUM *a, BIGNUM *N, BIGNUM *g) | |
236 | { | |
237 | BN_CTX *bn_ctx; | |
238 | BIGNUM * A = NULL; | |
239 | ||
240 | if (a == NULL || N == NULL || g == NULL || | |
241 | (bn_ctx = BN_CTX_new()) == NULL) | |
242 | return NULL; | |
243 | ||
244 | if ((A = BN_new()) != NULL && | |
245 | !BN_mod_exp(A,g,a,N,bn_ctx)) | |
246 | { | |
247 | BN_free(A); | |
248 | A = NULL; | |
249 | } | |
250 | BN_CTX_free(bn_ctx); | |
251 | return A; | |
252 | } | |
253 | ||
254 | ||
255 | BIGNUM *SRP_Calc_client_key(BIGNUM *N, BIGNUM *B, BIGNUM *g, BIGNUM *x, BIGNUM *a, BIGNUM *u) | |
256 | { | |
257 | BIGNUM *tmp = NULL, *tmp2 = NULL, *tmp3 = NULL , *k = NULL, *K = NULL; | |
258 | BN_CTX *bn_ctx; | |
259 | ||
260 | if (u == NULL || B == NULL || N == NULL || g == NULL || x == NULL || a == NULL || | |
261 | (bn_ctx = BN_CTX_new()) == NULL) | |
262 | return NULL; | |
263 | ||
264 | if ((tmp = BN_new()) == NULL || | |
265 | (tmp2 = BN_new())== NULL || | |
266 | (tmp3 = BN_new())== NULL || | |
267 | (K = BN_new()) == NULL) | |
268 | goto err; | |
269 | ||
270 | if (!BN_mod_exp(tmp,g,x,N,bn_ctx)) | |
271 | goto err; | |
272 | if (!(k = srp_Calc_k(N,g))) | |
273 | goto err; | |
274 | if (!BN_mod_mul(tmp2,tmp,k,N,bn_ctx)) | |
275 | goto err; | |
276 | if (!BN_mod_sub(tmp,B,tmp2,N,bn_ctx)) | |
277 | goto err; | |
278 | ||
279 | if (!BN_mod_mul(tmp3,u,x,N,bn_ctx)) | |
280 | goto err; | |
281 | if (!BN_mod_add(tmp2,a,tmp3,N,bn_ctx)) | |
282 | goto err; | |
283 | if (!BN_mod_exp(K,tmp,tmp2,N,bn_ctx)) | |
284 | goto err; | |
285 | ||
286 | err : | |
287 | BN_CTX_free(bn_ctx); | |
288 | BN_clear_free(tmp); | |
289 | BN_clear_free(tmp2); | |
290 | BN_clear_free(tmp3); | |
291 | BN_free(k); | |
292 | return K; | |
293 | } | |
294 | ||
295 | int SRP_Verify_B_mod_N(BIGNUM *B, BIGNUM *N) | |
296 | { | |
297 | BIGNUM *r; | |
298 | BN_CTX *bn_ctx; | |
299 | int ret = 0; | |
300 | ||
301 | if (B == NULL || N == NULL || | |
302 | (bn_ctx = BN_CTX_new()) == NULL) | |
303 | return 0; | |
304 | ||
305 | if ((r = BN_new()) == NULL) | |
306 | goto err; | |
307 | /* Checks if B % N == 0 */ | |
308 | if (!BN_nnmod(r,B,N,bn_ctx)) | |
309 | goto err; | |
310 | ret = !BN_is_zero(r); | |
311 | err: | |
312 | BN_CTX_free(bn_ctx); | |
313 | BN_free(r); | |
314 | return ret; | |
315 | } | |
316 | ||
317 | int SRP_Verify_A_mod_N(BIGNUM *A, BIGNUM *N) | |
318 | { | |
319 | /* Checks if A % N == 0 */ | |
320 | return SRP_Verify_B_mod_N(A,N) ; | |
321 | } | |
322 | ||
323 | ||
324 | /* Check if G and N are kwown parameters. | |
325 | The values have been generated from the ietf-tls-srp draft version 8 | |
326 | */ | |
327 | char * SRP_check_known_gN_param(BIGNUM* g, BIGNUM* N) | |
328 | { | |
329 | int i; | |
330 | if ((g == NULL) || (N == NULL)) | |
331 | return 0; | |
332 | ||
333 | srp_bn_print(g); | |
334 | srp_bn_print(N); | |
335 | ||
336 | for(i = 0; i < KNOWN_GN_NUMBER; i++) | |
337 | { | |
338 | if (BN_cmp(knowngN[i].g,g) == 0 && BN_cmp(knowngN[i].N,N) == 0) | |
339 | return knowngN[i].id; | |
340 | } | |
341 | return NULL; | |
342 | } | |
343 | ||
344 | SRP_gN *SRP_get_default_gN(const char * id) | |
345 | { | |
346 | int i; | |
347 | ||
348 | if (id == NULL) | |
349 | return knowngN; | |
350 | for(i = 0; i < KNOWN_GN_NUMBER; i++) | |
351 | { | |
352 | if (strcmp(knowngN[i].id,id)==0) | |
353 | return knowngN+i; | |
354 | } | |
355 | return NULL; | |
356 | } | |
357 | #endif |