/* 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