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0f113f3e | 1 | /* |
3b855b1f TH |
2 | * Copyright 2004-2018 The OpenSSL Project Authors. All Rights Reserved. |
3 | * Copyright (c) 2004, EdelKey Project. All Rights Reserved. | |
edc032b5 | 4 | * |
7428b99b | 5 | * Licensed under the Apache License 2.0 (the "License"). You may not use |
aa6bb135 RS |
6 | * this file except in compliance with the License. You can obtain a copy |
7 | * in the file LICENSE in the source distribution or at | |
8 | * https://www.openssl.org/source/license.html | |
3b855b1f TH |
9 | * |
10 | * Originally written by Christophe Renou and Peter Sylvester, | |
11 | * for the EdelKey project. | |
edc032b5 | 12 | */ |
aa6bb135 | 13 | |
edc032b5 | 14 | #ifndef OPENSSL_NO_SRP |
b39fc560 | 15 | # include "internal/cryptlib.h" |
dfb56425 | 16 | # include <openssl/sha.h> |
0f113f3e MC |
17 | # include <openssl/srp.h> |
18 | # include <openssl/evp.h> | |
25f2138b | 19 | # include "crypto/bn_srp.h" |
edc032b5 | 20 | |
8f332ac9 | 21 | /* calculate = SHA1(PAD(x) || PAD(y)) */ |
0f113f3e | 22 | |
8f332ac9 DSH |
23 | static BIGNUM *srp_Calc_xy(const BIGNUM *x, const BIGNUM *y, const BIGNUM *N) |
24 | { | |
0f113f3e | 25 | unsigned char digest[SHA_DIGEST_LENGTH]; |
c72b8e06 | 26 | unsigned char *tmp = NULL; |
8f332ac9 | 27 | int numN = BN_num_bytes(N); |
6e59a892 | 28 | BIGNUM *res = NULL; |
d63bde78 | 29 | |
8f332ac9 | 30 | if (x != N && BN_ucmp(x, N) >= 0) |
0f113f3e | 31 | return NULL; |
8f332ac9 | 32 | if (y != N && BN_ucmp(y, N) >= 0) |
0f113f3e | 33 | return NULL; |
8f332ac9 | 34 | if ((tmp = OPENSSL_malloc(numN * 2)) == NULL) |
d166ed8c | 35 | goto err; |
8f332ac9 DSH |
36 | if (BN_bn2binpad(x, tmp, numN) < 0 |
37 | || BN_bn2binpad(y, tmp + numN, numN) < 0 | |
38 | || !EVP_Digest(tmp, numN * 2, digest, NULL, EVP_sha1(), NULL)) | |
d166ed8c | 39 | goto err; |
6e59a892 RL |
40 | res = BN_bin2bn(digest, sizeof(digest), NULL); |
41 | err: | |
c72b8e06 | 42 | OPENSSL_free(tmp); |
6e59a892 | 43 | return res; |
0f113f3e | 44 | } |
edc032b5 | 45 | |
8f332ac9 DSH |
46 | static BIGNUM *srp_Calc_k(const BIGNUM *N, const BIGNUM *g) |
47 | { | |
495a1e5c | 48 | /* k = SHA1(N | PAD(g)) -- tls-srp RFC 5054 */ |
8f332ac9 DSH |
49 | return srp_Calc_xy(N, g, N); |
50 | } | |
51 | ||
98370c2d | 52 | BIGNUM *SRP_Calc_u(const BIGNUM *A, const BIGNUM *B, const BIGNUM *N) |
0f113f3e | 53 | { |
495a1e5c | 54 | /* u = SHA1(PAD(A) || PAD(B) ) -- tls-srp RFC 5054 */ |
8f332ac9 | 55 | return srp_Calc_xy(A, B, N); |
edc032b5 BL |
56 | } |
57 | ||
98370c2d MC |
58 | BIGNUM *SRP_Calc_server_key(const BIGNUM *A, const BIGNUM *v, const BIGNUM *u, |
59 | const BIGNUM *b, const BIGNUM *N) | |
0f113f3e MC |
60 | { |
61 | BIGNUM *tmp = NULL, *S = NULL; | |
62 | BN_CTX *bn_ctx; | |
63 | ||
64 | if (u == NULL || A == NULL || v == NULL || b == NULL || N == NULL) | |
65 | return NULL; | |
66 | ||
308ff286 | 67 | if ((bn_ctx = BN_CTX_new()) == NULL || (tmp = BN_new()) == NULL) |
0f113f3e MC |
68 | goto err; |
69 | ||
70 | /* S = (A*v**u) ** b */ | |
71 | ||
72 | if (!BN_mod_exp(tmp, v, u, N, bn_ctx)) | |
73 | goto err; | |
74 | if (!BN_mod_mul(tmp, A, tmp, N, bn_ctx)) | |
75 | goto err; | |
308ff286 MC |
76 | |
77 | S = BN_new(); | |
78 | if (S != NULL && !BN_mod_exp(S, tmp, b, N, bn_ctx)) { | |
79 | BN_free(S); | |
80 | S = NULL; | |
81 | } | |
0f113f3e MC |
82 | err: |
83 | BN_CTX_free(bn_ctx); | |
84 | BN_clear_free(tmp); | |
85 | return S; | |
86 | } | |
edc032b5 | 87 | |
98370c2d MC |
88 | BIGNUM *SRP_Calc_B(const BIGNUM *b, const BIGNUM *N, const BIGNUM *g, |
89 | const BIGNUM *v) | |
0f113f3e MC |
90 | { |
91 | BIGNUM *kv = NULL, *gb = NULL; | |
92 | BIGNUM *B = NULL, *k = NULL; | |
93 | BN_CTX *bn_ctx; | |
94 | ||
95 | if (b == NULL || N == NULL || g == NULL || v == NULL || | |
96 | (bn_ctx = BN_CTX_new()) == NULL) | |
97 | return NULL; | |
98 | ||
99 | if ((kv = BN_new()) == NULL || | |
100 | (gb = BN_new()) == NULL || (B = BN_new()) == NULL) | |
101 | goto err; | |
102 | ||
103 | /* B = g**b + k*v */ | |
104 | ||
75ebbd9a RS |
105 | if (!BN_mod_exp(gb, g, b, N, bn_ctx) |
106 | || (k = srp_Calc_k(N, g)) == NULL | |
107 | || !BN_mod_mul(kv, v, k, N, bn_ctx) | |
108 | || !BN_mod_add(B, gb, kv, N, bn_ctx)) { | |
0f113f3e MC |
109 | BN_free(B); |
110 | B = NULL; | |
111 | } | |
112 | err: | |
113 | BN_CTX_free(bn_ctx); | |
114 | BN_clear_free(kv); | |
115 | BN_clear_free(gb); | |
116 | BN_free(k); | |
117 | return B; | |
118 | } | |
edc032b5 | 119 | |
98370c2d | 120 | BIGNUM *SRP_Calc_x(const BIGNUM *s, const char *user, const char *pass) |
0f113f3e MC |
121 | { |
122 | unsigned char dig[SHA_DIGEST_LENGTH]; | |
6e59a892 | 123 | EVP_MD_CTX *ctxt; |
4162c7d3 | 124 | unsigned char *cs = NULL; |
6e59a892 | 125 | BIGNUM *res = NULL; |
0f113f3e MC |
126 | |
127 | if ((s == NULL) || (user == NULL) || (pass == NULL)) | |
128 | return NULL; | |
129 | ||
bfb0641f | 130 | ctxt = EVP_MD_CTX_new(); |
6e59a892 | 131 | if (ctxt == NULL) |
0f113f3e | 132 | return NULL; |
6e59a892 RL |
133 | if ((cs = OPENSSL_malloc(BN_num_bytes(s))) == NULL) |
134 | goto err; | |
0f113f3e | 135 | |
d166ed8c DSH |
136 | if (!EVP_DigestInit_ex(ctxt, EVP_sha1(), NULL) |
137 | || !EVP_DigestUpdate(ctxt, user, strlen(user)) | |
138 | || !EVP_DigestUpdate(ctxt, ":", 1) | |
139 | || !EVP_DigestUpdate(ctxt, pass, strlen(pass)) | |
140 | || !EVP_DigestFinal_ex(ctxt, dig, NULL) | |
141 | || !EVP_DigestInit_ex(ctxt, EVP_sha1(), NULL)) | |
142 | goto err; | |
d63bde78 MC |
143 | if (BN_bn2bin(s, cs) < 0) |
144 | goto err; | |
d166ed8c DSH |
145 | if (!EVP_DigestUpdate(ctxt, cs, BN_num_bytes(s))) |
146 | goto err; | |
4162c7d3 | 147 | |
d166ed8c DSH |
148 | if (!EVP_DigestUpdate(ctxt, dig, sizeof(dig)) |
149 | || !EVP_DigestFinal_ex(ctxt, dig, NULL)) | |
150 | goto err; | |
0f113f3e | 151 | |
6e59a892 | 152 | res = BN_bin2bn(dig, sizeof(dig), NULL); |
4162c7d3 | 153 | |
6e59a892 | 154 | err: |
4162c7d3 | 155 | OPENSSL_free(cs); |
bfb0641f | 156 | EVP_MD_CTX_free(ctxt); |
6e59a892 | 157 | return res; |
0f113f3e | 158 | } |
edc032b5 | 159 | |
98370c2d | 160 | BIGNUM *SRP_Calc_A(const BIGNUM *a, const BIGNUM *N, const BIGNUM *g) |
0f113f3e MC |
161 | { |
162 | BN_CTX *bn_ctx; | |
163 | BIGNUM *A = NULL; | |
164 | ||
23a1d5e9 | 165 | if (a == NULL || N == NULL || g == NULL || (bn_ctx = BN_CTX_new()) == NULL) |
0f113f3e MC |
166 | return NULL; |
167 | ||
168 | if ((A = BN_new()) != NULL && !BN_mod_exp(A, g, a, N, bn_ctx)) { | |
169 | BN_free(A); | |
170 | A = NULL; | |
171 | } | |
172 | BN_CTX_free(bn_ctx); | |
173 | return A; | |
174 | } | |
175 | ||
98370c2d MC |
176 | BIGNUM *SRP_Calc_client_key(const BIGNUM *N, const BIGNUM *B, const BIGNUM *g, |
177 | const BIGNUM *x, const BIGNUM *a, const BIGNUM *u) | |
0f113f3e MC |
178 | { |
179 | BIGNUM *tmp = NULL, *tmp2 = NULL, *tmp3 = NULL, *k = NULL, *K = NULL; | |
180 | BN_CTX *bn_ctx; | |
181 | ||
182 | if (u == NULL || B == NULL || N == NULL || g == NULL || x == NULL | |
183 | || a == NULL || (bn_ctx = BN_CTX_new()) == NULL) | |
184 | return NULL; | |
185 | ||
186 | if ((tmp = BN_new()) == NULL || | |
187 | (tmp2 = BN_new()) == NULL || | |
308ff286 | 188 | (tmp3 = BN_new()) == NULL) |
0f113f3e MC |
189 | goto err; |
190 | ||
191 | if (!BN_mod_exp(tmp, g, x, N, bn_ctx)) | |
192 | goto err; | |
75ebbd9a | 193 | if ((k = srp_Calc_k(N, g)) == NULL) |
0f113f3e MC |
194 | goto err; |
195 | if (!BN_mod_mul(tmp2, tmp, k, N, bn_ctx)) | |
196 | goto err; | |
197 | if (!BN_mod_sub(tmp, B, tmp2, N, bn_ctx)) | |
198 | goto err; | |
c9141a43 | 199 | if (!BN_mul(tmp3, u, x, bn_ctx)) |
0f113f3e | 200 | goto err; |
c9141a43 | 201 | if (!BN_add(tmp2, a, tmp3)) |
0f113f3e | 202 | goto err; |
308ff286 MC |
203 | K = BN_new(); |
204 | if (K != NULL && !BN_mod_exp(K, tmp, tmp2, N, bn_ctx)) { | |
205 | BN_free(K); | |
206 | K = NULL; | |
207 | } | |
0f113f3e MC |
208 | |
209 | err: | |
210 | BN_CTX_free(bn_ctx); | |
211 | BN_clear_free(tmp); | |
212 | BN_clear_free(tmp2); | |
213 | BN_clear_free(tmp3); | |
214 | BN_free(k); | |
215 | return K; | |
216 | } | |
edc032b5 | 217 | |
98370c2d | 218 | int SRP_Verify_B_mod_N(const BIGNUM *B, const BIGNUM *N) |
0f113f3e MC |
219 | { |
220 | BIGNUM *r; | |
221 | BN_CTX *bn_ctx; | |
222 | int ret = 0; | |
223 | ||
224 | if (B == NULL || N == NULL || (bn_ctx = BN_CTX_new()) == NULL) | |
225 | return 0; | |
226 | ||
227 | if ((r = BN_new()) == NULL) | |
228 | goto err; | |
229 | /* Checks if B % N == 0 */ | |
230 | if (!BN_nnmod(r, B, N, bn_ctx)) | |
231 | goto err; | |
232 | ret = !BN_is_zero(r); | |
233 | err: | |
234 | BN_CTX_free(bn_ctx); | |
235 | BN_free(r); | |
236 | return ret; | |
237 | } | |
edc032b5 | 238 | |
98370c2d | 239 | int SRP_Verify_A_mod_N(const BIGNUM *A, const BIGNUM *N) |
0f113f3e MC |
240 | { |
241 | /* Checks if A % N == 0 */ | |
242 | return SRP_Verify_B_mod_N(A, N); | |
243 | } | |
244 | ||
8cf27823 | 245 | static SRP_gN knowngN[] = { |
98370c2d MC |
246 | {"8192", &bn_generator_19, &bn_group_8192}, |
247 | {"6144", &bn_generator_5, &bn_group_6144}, | |
248 | {"4096", &bn_generator_5, &bn_group_4096}, | |
249 | {"3072", &bn_generator_5, &bn_group_3072}, | |
250 | {"2048", &bn_generator_2, &bn_group_2048}, | |
251 | {"1536", &bn_generator_2, &bn_group_1536}, | |
252 | {"1024", &bn_generator_2, &bn_group_1024}, | |
8cf27823 DSH |
253 | }; |
254 | ||
255 | # define KNOWN_GN_NUMBER sizeof(knowngN) / sizeof(SRP_gN) | |
256 | ||
0f113f3e | 257 | /* |
0d4fb843 | 258 | * Check if G and N are known parameters. The values have been generated |
495a1e5c | 259 | * from the IETF RFC 5054 |
0f113f3e | 260 | */ |
98370c2d | 261 | char *SRP_check_known_gN_param(const BIGNUM *g, const BIGNUM *N) |
0f113f3e MC |
262 | { |
263 | size_t i; | |
264 | if ((g == NULL) || (N == NULL)) | |
495a1e5c | 265 | return NULL; |
0f113f3e | 266 | |
0f113f3e MC |
267 | for (i = 0; i < KNOWN_GN_NUMBER; i++) { |
268 | if (BN_cmp(knowngN[i].g, g) == 0 && BN_cmp(knowngN[i].N, N) == 0) | |
269 | return knowngN[i].id; | |
270 | } | |
271 | return NULL; | |
272 | } | |
edc032b5 | 273 | |
71fa4513 | 274 | SRP_gN *SRP_get_default_gN(const char *id) |
0f113f3e MC |
275 | { |
276 | size_t i; | |
277 | ||
278 | if (id == NULL) | |
279 | return knowngN; | |
280 | for (i = 0; i < KNOWN_GN_NUMBER; i++) { | |
281 | if (strcmp(knowngN[i].id, id) == 0) | |
282 | return knowngN + i; | |
283 | } | |
284 | return NULL; | |
285 | } | |
edc032b5 | 286 | #endif |