release/src/router/openssl/crypto/srp/srp_lib.c

   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         size_t 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         size_t 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