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(const BIGNUM *N, const 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(const BIGNUM *A, const BIGNUM *B, const 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(const BIGNUM *A, const BIGNUM *v, const BIGNUM *u,
99 const BIGNUM *b, const BIGNUM *N)
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(const BIGNUM *b, const BIGNUM *N, const BIGNUM *g,
131 BIGNUM *kv = NULL, *gb = NULL;
132 BIGNUM *B = NULL, *k = NULL;
135 if (b == NULL || N == NULL || g == NULL || v == NULL ||
136 (bn_ctx = BN_CTX_new()) == NULL)
139 if ((kv = BN_new()) == NULL ||
140 (gb = BN_new()) == NULL || (B = BN_new()) == NULL)
145 if (!BN_mod_exp(gb, g, b, N, bn_ctx)
146 || (k = srp_Calc_k(N, g)) == NULL
147 || !BN_mod_mul(kv, v, k, N, bn_ctx)
148 || !BN_mod_add(B, gb, kv, N, bn_ctx)) {
160 BIGNUM *SRP_Calc_x(const BIGNUM *s, const char *user, const char *pass)
162 unsigned char dig[SHA_DIGEST_LENGTH];
167 if ((s == NULL) || (user == NULL) || (pass == NULL))
170 ctxt = EVP_MD_CTX_new();
173 if ((cs = OPENSSL_malloc(BN_num_bytes(s))) == NULL)
176 EVP_DigestInit_ex(ctxt, EVP_sha1(), NULL);
177 EVP_DigestUpdate(ctxt, user, strlen(user));
178 EVP_DigestUpdate(ctxt, ":", 1);
179 EVP_DigestUpdate(ctxt, pass, strlen(pass));
180 EVP_DigestFinal_ex(ctxt, dig, NULL);
182 EVP_DigestInit_ex(ctxt, EVP_sha1(), NULL);
184 EVP_DigestUpdate(ctxt, cs, BN_num_bytes(s));
186 EVP_DigestUpdate(ctxt, dig, sizeof(dig));
187 EVP_DigestFinal_ex(ctxt, dig, NULL);
189 res = BN_bin2bn(dig, sizeof(dig), NULL);
191 EVP_MD_CTX_free(ctxt);
195 BIGNUM *SRP_Calc_A(const BIGNUM *a, const BIGNUM *N, const BIGNUM *g)
200 if (a == NULL || N == NULL || g == NULL || (bn_ctx = BN_CTX_new()) == NULL)
203 if ((A = BN_new()) != NULL && !BN_mod_exp(A, g, a, N, bn_ctx)) {
211 BIGNUM *SRP_Calc_client_key(const BIGNUM *N, const BIGNUM *B, const BIGNUM *g,
212 const BIGNUM *x, const BIGNUM *a, const BIGNUM *u)
214 BIGNUM *tmp = NULL, *tmp2 = NULL, *tmp3 = NULL, *k = NULL, *K = NULL;
217 if (u == NULL || B == NULL || N == NULL || g == NULL || x == NULL
218 || a == NULL || (bn_ctx = BN_CTX_new()) == NULL)
221 if ((tmp = BN_new()) == NULL ||
222 (tmp2 = BN_new()) == NULL ||
223 (tmp3 = BN_new()) == NULL)
226 if (!BN_mod_exp(tmp, g, x, N, bn_ctx))
228 if ((k = srp_Calc_k(N, g)) == NULL)
230 if (!BN_mod_mul(tmp2, tmp, k, N, bn_ctx))
232 if (!BN_mod_sub(tmp, B, tmp2, N, bn_ctx))
234 if (!BN_mul(tmp3, u, x, bn_ctx))
236 if (!BN_add(tmp2, a, tmp3))
239 if (K != NULL && !BN_mod_exp(K, tmp, tmp2, N, bn_ctx)) {
253 int SRP_Verify_B_mod_N(const BIGNUM *B, const BIGNUM *N)
259 if (B == NULL || N == NULL || (bn_ctx = BN_CTX_new()) == NULL)
262 if ((r = BN_new()) == NULL)
264 /* Checks if B % N == 0 */
265 if (!BN_nnmod(r, B, N, bn_ctx))
267 ret = !BN_is_zero(r);
274 int SRP_Verify_A_mod_N(const BIGNUM *A, const BIGNUM *N)
276 /* Checks if A % N == 0 */
277 return SRP_Verify_B_mod_N(A, N);
280 static SRP_gN knowngN[] = {
281 {"8192", &bn_generator_19, &bn_group_8192},
282 {"6144", &bn_generator_5, &bn_group_6144},
283 {"4096", &bn_generator_5, &bn_group_4096},
284 {"3072", &bn_generator_5, &bn_group_3072},
285 {"2048", &bn_generator_2, &bn_group_2048},
286 {"1536", &bn_generator_2, &bn_group_1536},
287 {"1024", &bn_generator_2, &bn_group_1024},
290 # define KNOWN_GN_NUMBER sizeof(knowngN) / sizeof(SRP_gN)
293 * Check if G and N are known parameters. The values have been generated
294 * from the ietf-tls-srp draft version 8
296 char *SRP_check_known_gN_param(const BIGNUM *g, const BIGNUM *N)
299 if ((g == NULL) || (N == NULL))
302 for (i = 0; i < KNOWN_GN_NUMBER; i++) {
303 if (BN_cmp(knowngN[i].g, g) == 0 && BN_cmp(knowngN[i].N, N) == 0)
304 return knowngN[i].id;
309 SRP_gN *SRP_get_default_gN(const char *id)
315 for (i = 0; i < KNOWN_GN_NUMBER; i++) {
316 if (strcmp(knowngN[i].id, id) == 0)