aboutsummaryrefslogtreecommitdiffstats
path: root/crypto/srp/srp_lib.c
blob: e9a2e058f687740aa2d251f24e3551c49ffc7024 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
/* crypto/srp/srp_lib.c */
/*
 * Written by Christophe Renou (christophe.renou@edelweb.fr) with the
 * precious help of Peter Sylvester (peter.sylvester@edelweb.fr) for the
 * EdelKey project and contributed to the OpenSSL project 2004.
 */
/* ====================================================================
 * Copyright (c) 2004 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */
#ifndef OPENSSL_NO_SRP
# include "cryptlib.h"
# include "srp_lcl.h"
# include <openssl/srp.h>
# include <openssl/evp.h>

# if (BN_BYTES == 8)
#  if (defined(_WIN32) || defined(_WIN64)) && !defined(__MINGW32__)
#   define bn_pack4(a1,a2,a3,a4) ((a1##UI64<<48)|(a2##UI64<<32)|(a3##UI64<<16)|a4##UI64)
#  elif defined(__arch64__)
#   define bn_pack4(a1,a2,a3,a4) ((a1##UL<<48)|(a2##UL<<32)|(a3##UL<<16)|a4##UL)
#  else
#   define bn_pack4(a1,a2,a3,a4) ((a1##ULL<<48)|(a2##ULL<<32)|(a3##ULL<<16)|a4##ULL)
#  endif
# elif (BN_BYTES == 4)
#  define bn_pack4(a1,a2,a3,a4)  ((a3##UL<<16)|a4##UL), ((a1##UL<<16)|a2##UL)
# else
#  error "unsupported BN_BYTES"
# endif

# include "srp_grps.h"

static BIGNUM *srp_Calc_k(BIGNUM *N, BIGNUM *g)
{
    /* k = SHA1(N | PAD(g)) -- tls-srp draft 8 */

    unsigned char digest[SHA_DIGEST_LENGTH];
    unsigned char *tmp;
    EVP_MD_CTX ctxt;
    int longg;
    int longN = BN_num_bytes(N);

    if (BN_ucmp(g, N) >= 0)
        return NULL;

    if ((tmp = OPENSSL_malloc(longN)) == NULL)
        return NULL;
    BN_bn2bin(N, tmp);

    EVP_MD_CTX_init(&ctxt);
    EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL);
    EVP_DigestUpdate(&ctxt, tmp, longN);

    memset(tmp, 0, longN);
    longg = BN_bn2bin(g, tmp);
    /* use the zeros behind to pad on left */
    EVP_DigestUpdate(&ctxt, tmp + longg, longN - longg);
    EVP_DigestUpdate(&ctxt, tmp, longg);
    OPENSSL_free(tmp);

    EVP_DigestFinal_ex(&ctxt, digest, NULL);
    EVP_MD_CTX_cleanup(&ctxt);
    return BN_bin2bn(digest, sizeof(digest), NULL);
}

BIGNUM *SRP_Calc_u(BIGNUM *A, BIGNUM *B, BIGNUM *N)
{
    /* k = SHA1(PAD(A) || PAD(B) ) -- tls-srp draft 8 */

    BIGNUM *u;
    unsigned char cu[SHA_DIGEST_LENGTH];
    unsigned char *cAB;
    EVP_MD_CTX ctxt;
    int longN;
    if ((A == NULL) || (B == NULL) || (N == NULL))
        return NULL;

    if (BN_ucmp(A, N) >= 0 || BN_ucmp(B, N) >= 0)
        return NULL;

    longN = BN_num_bytes(N);

    if ((cAB = OPENSSL_malloc(2 * longN)) == NULL)
        return NULL;

    memset(cAB, 0, longN);

    EVP_MD_CTX_init(&ctxt);
    EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL);
    EVP_DigestUpdate(&ctxt, cAB + BN_bn2bin(A, cAB + longN), longN);
    EVP_DigestUpdate(&ctxt, cAB + BN_bn2bin(B, cAB + longN), longN);
    OPENSSL_free(cAB);
    EVP_DigestFinal_ex(&ctxt, cu, NULL);
    EVP_MD_CTX_cleanup(&ctxt);

    if (!(u = BN_bin2bn(cu, sizeof(cu), NULL)))
        return NULL;
    if (!BN_is_zero(u))
        return u;
    BN_free(u);
    return NULL;
}

BIGNUM *SRP_Calc_server_key(BIGNUM *A, BIGNUM *v, BIGNUM *u, BIGNUM *b,
                            BIGNUM *N)
{
    BIGNUM *tmp = NULL, *S = NULL;
    BN_CTX *bn_ctx;

    if (u == NULL || A == NULL || v == NULL || b == NULL || N == NULL)
        return NULL;

    if ((bn_ctx = BN_CTX_new()) == NULL ||
        (tmp = BN_new()) == NULL || (S = BN_new()) == NULL)
        goto err;

    /* S = (A*v**u) ** b */

    if (!BN_mod_exp(tmp, v, u, N, bn_ctx))
        goto err;
    if (!BN_mod_mul(tmp, A, tmp, N, bn_ctx))
        goto err;
    if (!BN_mod_exp(S, tmp, b, N, bn_ctx))
        goto err;
 err:
    BN_CTX_free(bn_ctx);
    BN_clear_free(tmp);
    return S;
}

BIGNUM *SRP_Calc_B(BIGNUM *b, BIGNUM *N, BIGNUM *g, BIGNUM *v)
{
    BIGNUM *kv = NULL, *gb = NULL;
    BIGNUM *B = NULL, *k = NULL;
    BN_CTX *bn_ctx;

    if (b == NULL || N == NULL || g == NULL || v == NULL ||
        (bn_ctx = BN_CTX_new()) == NULL)
        return NULL;

    if ((kv = BN_new()) == NULL ||
        (gb = BN_new()) == NULL || (B = BN_new()) == NULL)
        goto err;

    /* B = g**b + k*v */

    if (!BN_mod_exp(gb, g, b, N, bn_ctx) ||
        !(k = srp_Calc_k(N, g)) ||
        !BN_mod_mul(kv, v, k, N, bn_ctx) ||
        !BN_mod_add(B, gb, kv, N, bn_ctx)) {
        BN_free(B);
        B = NULL;
    }
 err:
    BN_CTX_free(bn_ctx);
    BN_clear_free(kv);
    BN_clear_free(gb);
    BN_free(k);
    return B;
}

BIGNUM *SRP_Calc_x(BIGNUM *s, const char *user, const char *pass)
{
    unsigned char dig[SHA_DIGEST_LENGTH];
    EVP_MD_CTX ctxt;
    unsigned char *cs;

    if ((s == NULL) || (user == NULL) || (pass == NULL))
        return NULL;

    if ((cs = OPENSSL_malloc(BN_num_bytes(s))) == NULL)
        return NULL;

    EVP_MD_CTX_init(&ctxt);
    EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL);
    EVP_DigestUpdate(&ctxt, user, strlen(user));
    EVP_DigestUpdate(&ctxt, ":", 1);
    EVP_DigestUpdate(&ctxt, pass, strlen(pass));
    EVP_DigestFinal_ex(&ctxt, dig, NULL);

    EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL);
    BN_bn2bin(s, cs);
    EVP_DigestUpdate(&ctxt, cs, BN_num_bytes(s));
    OPENSSL_free(cs);
    EVP_DigestUpdate(&ctxt, dig, sizeof(dig));
    EVP_DigestFinal_ex(&ctxt, dig, NULL);
    EVP_MD_CTX_cleanup(&ctxt);

    return BN_bin2bn(dig, sizeof(dig), NULL);
}

BIGNUM *SRP_Calc_A(BIGNUM *a, BIGNUM *N, BIGNUM *g)
{
    BN_CTX *bn_ctx;
    BIGNUM *A = NULL;

    if (a == NULL || N == NULL || g == NULL ||
        (bn_ctx = BN_CTX_new()) == NULL)
        return NULL;

    if ((A = BN_new()) != NULL && !BN_mod_exp(A, g, a, N, bn_ctx)) {
        BN_free(A);
        A = NULL;
    }
    BN_CTX_free(bn_ctx);
    return A;
}

BIGNUM *SRP_Calc_client_key(BIGNUM *N, BIGNUM *B, BIGNUM *g, BIGNUM *x,
                            BIGNUM *a, BIGNUM *u)
{
    BIGNUM *tmp = NULL, *tmp2 = NULL, *tmp3 = NULL, *k = NULL, *K = NULL;
    BN_CTX *bn_ctx;

    if (u == NULL || B == NULL || N == NULL || g == NULL || x == NULL
        || a == NULL || (bn_ctx = BN_CTX_new()) == NULL)
        return NULL;

    if ((tmp = BN_new()) == NULL ||
        (tmp2 = BN_new()) == NULL ||
        (tmp3 = BN_new()) == NULL || (K = BN_new()) == NULL)
        goto err;

    if (!BN_mod_exp(tmp, g, x, N, bn_ctx))
        goto err;
    if (!(k = srp_Calc_k(N, g)))
        goto err;
    if (!BN_mod_mul(tmp2, tmp, k, N, bn_ctx))
        goto err;
    if (!BN_mod_sub(tmp, B, tmp2, N, bn_ctx))
        goto err;

    if (!BN_mod_mul(tmp3, u, x, N, bn_ctx))
        goto err;
    if (!BN_mod_add(tmp2, a, tmp3, N, bn_ctx))
        goto err;
    if (!BN_mod_exp(K, tmp, tmp2, N, bn_ctx))
        goto err;

 err:
    BN_CTX_free(bn_ctx);
    BN_clear_free(tmp);
    BN_clear_free(tmp2);
    BN_clear_free(tmp3);
    BN_free(k);
    return K;
}

int SRP_Verify_B_mod_N(BIGNUM *B, BIGNUM *N)
{
    BIGNUM *r;
    BN_CTX *bn_ctx;
    int ret = 0;

    if (B == NULL || N == NULL || (bn_ctx = BN_CTX_new()) == NULL)
        return 0;

    if ((r = BN_new()) == NULL)
        goto err;
    /* Checks if B % N == 0 */
    if (!BN_nnmod(r, B, N, bn_ctx))
        goto err;
    ret = !BN_is_zero(r);
 err:
    BN_CTX_free(bn_ctx);
    BN_free(r);
    return ret;
}

int SRP_Verify_A_mod_N(BIGNUM *A, BIGNUM *N)
{
    /* Checks if A % N == 0 */
    return SRP_Verify_B_mod_N(A, N);
}

/*
 * Check if G and N are kwown parameters. The values have been generated
 * from the ietf-tls-srp draft version 8
 */
char *SRP_check_known_gN_param(BIGNUM *g, BIGNUM *N)
{
    size_t i;
    if ((g == NULL) || (N == NULL))
        return 0;

    srp_bn_print(g);
    srp_bn_print(N);

    for (i = 0; i < KNOWN_GN_NUMBER; i++) {
        if (BN_cmp(knowngN[i].g, g) == 0 && BN_cmp(knowngN[i].N, N) == 0)
            return knowngN[i].id;
    }
    return NULL;
}

SRP_gN *SRP_get_default_gN(const char *id)
{
    size_t i;

    if (id == NULL)
        return knowngN;
    for (i = 0; i < KNOWN_GN_NUMBER; i++) {
        if (strcmp(knowngN[i].id, id) == 0)
            return knowngN + i;
    }
    return NULL;
}
#endif