2 * Copyright 2011-2016 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
10 #ifndef OPENSSL_NO_SRP
11 # include "internal/cryptlib.h"
12 # include <openssl/sha.h>
13 # include <openssl/srp.h>
14 # include <openssl/evp.h>
15 # include "internal/bn_srp.h"
17 static BIGNUM *srp_Calc_k(BIGNUM *N, BIGNUM *g)
19 /* k = SHA1(N | PAD(g)) -- tls-srp draft 8 */
21 unsigned char digest[SHA_DIGEST_LENGTH];
23 EVP_MD_CTX *ctxt = NULL;
25 int longN = BN_num_bytes(N);
28 if (BN_ucmp(g, N) >= 0)
31 ctxt = EVP_MD_CTX_new();
34 if ((tmp = OPENSSL_malloc(longN)) == NULL)
38 EVP_DigestInit_ex(ctxt, EVP_sha1(), NULL);
39 EVP_DigestUpdate(ctxt, tmp, longN);
41 memset(tmp, 0, longN);
42 longg = BN_bn2bin(g, tmp);
43 /* use the zeros behind to pad on left */
44 EVP_DigestUpdate(ctxt, tmp + longg, longN - longg);
45 EVP_DigestUpdate(ctxt, tmp, longg);
48 EVP_DigestFinal_ex(ctxt, digest, NULL);
49 res = BN_bin2bn(digest, sizeof(digest), NULL);
51 EVP_MD_CTX_free(ctxt);
55 BIGNUM *SRP_Calc_u(BIGNUM *A, BIGNUM *B, BIGNUM *N)
57 /* k = SHA1(PAD(A) || PAD(B) ) -- tls-srp draft 8 */
60 unsigned char cu[SHA_DIGEST_LENGTH];
61 unsigned char *cAB = NULL;
62 EVP_MD_CTX *ctxt = NULL;
64 if ((A == NULL) || (B == NULL) || (N == NULL))
67 if (BN_ucmp(A, N) >= 0 || BN_ucmp(B, N) >= 0)
70 longN = BN_num_bytes(N);
72 ctxt = EVP_MD_CTX_new();
75 if ((cAB = OPENSSL_malloc(2 * longN)) == NULL)
78 memset(cAB, 0, longN);
80 EVP_DigestInit_ex(ctxt, EVP_sha1(), NULL);
81 EVP_DigestUpdate(ctxt, cAB + BN_bn2bin(A, cAB + longN), longN);
82 EVP_DigestUpdate(ctxt, cAB + BN_bn2bin(B, cAB + longN), longN);
84 EVP_DigestFinal_ex(ctxt, cu, NULL);
86 if ((u = BN_bin2bn(cu, sizeof(cu), NULL)) == NULL)
93 EVP_MD_CTX_free(ctxt);
98 BIGNUM *SRP_Calc_server_key(BIGNUM *A, BIGNUM *v, BIGNUM *u, BIGNUM *b,
101 BIGNUM *tmp = NULL, *S = NULL;
104 if (u == NULL || A == NULL || v == NULL || b == NULL || N == NULL)
107 if ((bn_ctx = BN_CTX_new()) == NULL || (tmp = BN_new()) == NULL)
110 /* S = (A*v**u) ** b */
112 if (!BN_mod_exp(tmp, v, u, N, bn_ctx))
114 if (!BN_mod_mul(tmp, A, tmp, N, bn_ctx))
118 if (S != NULL && !BN_mod_exp(S, tmp, b, N, bn_ctx)) {
128 BIGNUM *SRP_Calc_B(BIGNUM *b, BIGNUM *N, BIGNUM *g, BIGNUM *v)
130 BIGNUM *kv = NULL, *gb = NULL;
131 BIGNUM *B = NULL, *k = NULL;
134 if (b == NULL || N == NULL || g == NULL || v == NULL ||
135 (bn_ctx = BN_CTX_new()) == NULL)
138 if ((kv = BN_new()) == NULL ||
139 (gb = BN_new()) == NULL || (B = BN_new()) == NULL)
144 if (!BN_mod_exp(gb, g, b, N, bn_ctx)
145 || (k = srp_Calc_k(N, g)) == NULL
146 || !BN_mod_mul(kv, v, k, N, bn_ctx)
147 || !BN_mod_add(B, gb, kv, N, bn_ctx)) {
159 BIGNUM *SRP_Calc_x(BIGNUM *s, const char *user, const char *pass)
161 unsigned char dig[SHA_DIGEST_LENGTH];
166 if ((s == NULL) || (user == NULL) || (pass == NULL))
169 ctxt = EVP_MD_CTX_new();
172 if ((cs = OPENSSL_malloc(BN_num_bytes(s))) == NULL)
175 EVP_DigestInit_ex(ctxt, EVP_sha1(), NULL);
176 EVP_DigestUpdate(ctxt, user, strlen(user));
177 EVP_DigestUpdate(ctxt, ":", 1);
178 EVP_DigestUpdate(ctxt, pass, strlen(pass));
179 EVP_DigestFinal_ex(ctxt, dig, NULL);
181 EVP_DigestInit_ex(ctxt, EVP_sha1(), NULL);
183 EVP_DigestUpdate(ctxt, cs, BN_num_bytes(s));
185 EVP_DigestUpdate(ctxt, dig, sizeof(dig));
186 EVP_DigestFinal_ex(ctxt, dig, NULL);
188 res = BN_bin2bn(dig, sizeof(dig), NULL);
190 EVP_MD_CTX_free(ctxt);
194 BIGNUM *SRP_Calc_A(BIGNUM *a, BIGNUM *N, BIGNUM *g)
199 if (a == NULL || N == NULL || g == NULL || (bn_ctx = BN_CTX_new()) == NULL)
202 if ((A = BN_new()) != NULL && !BN_mod_exp(A, g, a, N, bn_ctx)) {
210 BIGNUM *SRP_Calc_client_key(BIGNUM *N, BIGNUM *B, BIGNUM *g, BIGNUM *x,
211 BIGNUM *a, BIGNUM *u)
213 BIGNUM *tmp = NULL, *tmp2 = NULL, *tmp3 = NULL, *k = NULL, *K = NULL;
216 if (u == NULL || B == NULL || N == NULL || g == NULL || x == NULL
217 || a == NULL || (bn_ctx = BN_CTX_new()) == NULL)
220 if ((tmp = BN_new()) == NULL ||
221 (tmp2 = BN_new()) == NULL ||
222 (tmp3 = BN_new()) == NULL)
225 if (!BN_mod_exp(tmp, g, x, N, bn_ctx))
227 if ((k = srp_Calc_k(N, g)) == NULL)
229 if (!BN_mod_mul(tmp2, tmp, k, N, bn_ctx))
231 if (!BN_mod_sub(tmp, B, tmp2, N, bn_ctx))
233 if (!BN_mul(tmp3, u, x, bn_ctx))
235 if (!BN_add(tmp2, a, tmp3))
238 if (K != NULL && !BN_mod_exp(K, tmp, tmp2, N, bn_ctx)) {
252 int SRP_Verify_B_mod_N(BIGNUM *B, BIGNUM *N)
258 if (B == NULL || N == NULL || (bn_ctx = BN_CTX_new()) == NULL)
261 if ((r = BN_new()) == NULL)
263 /* Checks if B % N == 0 */
264 if (!BN_nnmod(r, B, N, bn_ctx))
266 ret = !BN_is_zero(r);
273 int SRP_Verify_A_mod_N(BIGNUM *A, BIGNUM *N)
275 /* Checks if A % N == 0 */
276 return SRP_Verify_B_mod_N(A, N);
279 static SRP_gN knowngN[] = {
280 {"8192", (BIGNUM *)&bn_generator_19, (BIGNUM *)&bn_group_8192},
281 {"6144", (BIGNUM *)&bn_generator_5, (BIGNUM *)&bn_group_6144},
282 {"4096", (BIGNUM *)&bn_generator_5, (BIGNUM *)&bn_group_4096},
283 {"3072", (BIGNUM *)&bn_generator_5, (BIGNUM *)&bn_group_3072},
284 {"2048", (BIGNUM *)&bn_generator_2, (BIGNUM *)&bn_group_2048},
285 {"1536", (BIGNUM *)&bn_generator_2, (BIGNUM *)&bn_group_1536},
286 {"1024", (BIGNUM *)&bn_generator_2, (BIGNUM *)&bn_group_1024},
289 # define KNOWN_GN_NUMBER sizeof(knowngN) / sizeof(SRP_gN)
292 * Check if G and N are known parameters. The values have been generated
293 * from the ietf-tls-srp draft version 8
295 char *SRP_check_known_gN_param(BIGNUM *g, BIGNUM *N)
298 if ((g == NULL) || (N == NULL))
301 for (i = 0; i < KNOWN_GN_NUMBER; i++) {
302 if (BN_cmp(knowngN[i].g, g) == 0 && BN_cmp(knowngN[i].N, N) == 0)
303 return knowngN[i].id;
308 SRP_gN *SRP_get_default_gN(const char *id)
314 for (i = 0; i < KNOWN_GN_NUMBER; i++) {
315 if (strcmp(knowngN[i].id, id) == 0)