4a23b12a03
Invalid parameters passed to the SRP code can be overrun an internal buffer. Add sanity check that g, A, B < N to SRP code. Thanks to Sean Devlin and Watson Ladd of Cryptography Services, NCC Group for reporting this issue.
367 lines
9.4 KiB
C
367 lines
9.4 KiB
C
/* crypto/srp/srp_lib.c */
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/* Written by Christophe Renou (christophe.renou@edelweb.fr) with
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* the precious help of Peter Sylvester (peter.sylvester@edelweb.fr)
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* for the EdelKey project and contributed to the OpenSSL project 2004.
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*/
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/* ====================================================================
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* Copyright (c) 2004 The OpenSSL Project. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* 3. All advertising materials mentioning features or use of this
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* software must display the following acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
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*
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* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
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* endorse or promote products derived from this software without
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* prior written permission. For written permission, please contact
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* licensing@OpenSSL.org.
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*
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* 5. Products derived from this software may not be called "OpenSSL"
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* nor may "OpenSSL" appear in their names without prior written
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* permission of the OpenSSL Project.
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*
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* 6. Redistributions of any form whatsoever must retain the following
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* acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
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*
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* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
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* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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* ====================================================================
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*
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* This product includes cryptographic software written by Eric Young
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* (eay@cryptsoft.com). This product includes software written by Tim
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* Hudson (tjh@cryptsoft.com).
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*
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*/
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#ifndef OPENSSL_NO_SRP
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#include "cryptlib.h"
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#include "srp_lcl.h"
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#include <openssl/srp.h>
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#include <openssl/evp.h>
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#if (BN_BYTES == 8)
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# if (defined(_WIN32) || defined(_WIN64)) && !defined(__MINGW32__)
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# define bn_pack4(a1,a2,a3,a4) ((a1##UI64<<48)|(a2##UI64<<32)|(a3##UI64<<16)|a4##UI64)
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# elif defined(__arch64__)
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# define bn_pack4(a1,a2,a3,a4) ((a1##UL<<48)|(a2##UL<<32)|(a3##UL<<16)|a4##UL)
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# else
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# define bn_pack4(a1,a2,a3,a4) ((a1##ULL<<48)|(a2##ULL<<32)|(a3##ULL<<16)|a4##ULL)
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# endif
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#elif (BN_BYTES == 4)
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# define bn_pack4(a1,a2,a3,a4) ((a3##UL<<16)|a4##UL), ((a1##UL<<16)|a2##UL)
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#else
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# error "unsupported BN_BYTES"
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#endif
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#include "srp_grps.h"
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static BIGNUM *srp_Calc_k(BIGNUM *N, BIGNUM *g)
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{
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/* k = SHA1(N | PAD(g)) -- tls-srp draft 8 */
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unsigned char digest[SHA_DIGEST_LENGTH];
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unsigned char *tmp;
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EVP_MD_CTX ctxt;
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int longg ;
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int longN = BN_num_bytes(N);
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if (BN_ucmp(g, N) >= 0)
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return NULL;
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if ((tmp = OPENSSL_malloc(longN)) == NULL)
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return NULL;
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BN_bn2bin(N,tmp) ;
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EVP_MD_CTX_init(&ctxt);
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EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL);
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EVP_DigestUpdate(&ctxt, tmp, longN);
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memset(tmp, 0, longN);
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longg = BN_bn2bin(g,tmp) ;
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/* use the zeros behind to pad on left */
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EVP_DigestUpdate(&ctxt, tmp + longg, longN-longg);
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EVP_DigestUpdate(&ctxt, tmp, longg);
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OPENSSL_free(tmp);
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EVP_DigestFinal_ex(&ctxt, digest, NULL);
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EVP_MD_CTX_cleanup(&ctxt);
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return BN_bin2bn(digest, sizeof(digest), NULL);
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}
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BIGNUM *SRP_Calc_u(BIGNUM *A, BIGNUM *B, BIGNUM *N)
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{
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/* k = SHA1(PAD(A) || PAD(B) ) -- tls-srp draft 8 */
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BIGNUM *u;
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unsigned char cu[SHA_DIGEST_LENGTH];
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unsigned char *cAB;
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EVP_MD_CTX ctxt;
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int longN;
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if ((A == NULL) ||(B == NULL) || (N == NULL))
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return NULL;
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if (BN_ucmp(A, N) >= 0 || BN_ucmp(B, N) >= 0)
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return NULL;
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longN= BN_num_bytes(N);
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if ((cAB = OPENSSL_malloc(2*longN)) == NULL)
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return NULL;
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memset(cAB, 0, longN);
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EVP_MD_CTX_init(&ctxt);
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EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL);
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EVP_DigestUpdate(&ctxt, cAB + BN_bn2bin(A,cAB+longN), longN);
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EVP_DigestUpdate(&ctxt, cAB + BN_bn2bin(B,cAB+longN), longN);
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OPENSSL_free(cAB);
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EVP_DigestFinal_ex(&ctxt, cu, NULL);
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EVP_MD_CTX_cleanup(&ctxt);
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if (!(u = BN_bin2bn(cu, sizeof(cu), NULL)))
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return NULL;
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if (!BN_is_zero(u))
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return u;
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BN_free(u);
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return NULL;
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}
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BIGNUM *SRP_Calc_server_key(BIGNUM *A, BIGNUM *v, BIGNUM *u, BIGNUM *b, BIGNUM *N)
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{
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BIGNUM *tmp = NULL, *S = NULL;
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BN_CTX *bn_ctx;
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if (u == NULL || A == NULL || v == NULL || b == NULL || N == NULL)
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return NULL;
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if ((bn_ctx = BN_CTX_new()) == NULL ||
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(tmp = BN_new()) == NULL ||
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(S = BN_new()) == NULL )
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goto err;
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/* S = (A*v**u) ** b */
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if (!BN_mod_exp(tmp,v,u,N,bn_ctx))
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goto err;
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if (!BN_mod_mul(tmp,A,tmp,N,bn_ctx))
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goto err;
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if (!BN_mod_exp(S,tmp,b,N,bn_ctx))
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goto err;
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err:
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BN_CTX_free(bn_ctx);
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BN_clear_free(tmp);
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return S;
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}
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BIGNUM *SRP_Calc_B(BIGNUM *b, BIGNUM *N, BIGNUM *g, BIGNUM *v)
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{
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BIGNUM *kv = NULL, *gb = NULL;
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BIGNUM *B = NULL, *k = NULL;
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BN_CTX *bn_ctx;
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if (b == NULL || N == NULL || g == NULL || v == NULL ||
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(bn_ctx = BN_CTX_new()) == NULL)
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return NULL;
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if ( (kv = BN_new()) == NULL ||
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(gb = BN_new()) == NULL ||
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(B = BN_new())== NULL)
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goto err;
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/* B = g**b + k*v */
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if (!BN_mod_exp(gb,g,b,N,bn_ctx) ||
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!(k = srp_Calc_k(N,g)) ||
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!BN_mod_mul(kv,v,k,N,bn_ctx) ||
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!BN_mod_add(B,gb,kv,N,bn_ctx))
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{
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BN_free(B);
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B = NULL;
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}
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err:
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BN_CTX_free(bn_ctx);
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BN_clear_free(kv);
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BN_clear_free(gb);
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BN_free(k);
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return B;
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}
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BIGNUM *SRP_Calc_x(BIGNUM *s, const char *user, const char *pass)
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{
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unsigned char dig[SHA_DIGEST_LENGTH];
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EVP_MD_CTX ctxt;
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unsigned char *cs;
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if ((s == NULL) ||
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(user == NULL) ||
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(pass == NULL))
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return NULL;
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if ((cs = OPENSSL_malloc(BN_num_bytes(s))) == NULL)
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return NULL;
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EVP_MD_CTX_init(&ctxt);
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EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL);
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EVP_DigestUpdate(&ctxt, user, strlen(user));
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EVP_DigestUpdate(&ctxt, ":", 1);
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EVP_DigestUpdate(&ctxt, pass, strlen(pass));
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EVP_DigestFinal_ex(&ctxt, dig, NULL);
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EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL);
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BN_bn2bin(s,cs);
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EVP_DigestUpdate(&ctxt, cs, BN_num_bytes(s));
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OPENSSL_free(cs);
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EVP_DigestUpdate(&ctxt, dig, sizeof(dig));
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EVP_DigestFinal_ex(&ctxt, dig, NULL);
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EVP_MD_CTX_cleanup(&ctxt);
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return BN_bin2bn(dig, sizeof(dig), NULL);
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}
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BIGNUM *SRP_Calc_A(BIGNUM *a, BIGNUM *N, BIGNUM *g)
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{
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BN_CTX *bn_ctx;
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BIGNUM * A = NULL;
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if (a == NULL || N == NULL || g == NULL ||
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(bn_ctx = BN_CTX_new()) == NULL)
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return NULL;
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if ((A = BN_new()) != NULL &&
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!BN_mod_exp(A,g,a,N,bn_ctx))
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{
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BN_free(A);
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A = NULL;
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}
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BN_CTX_free(bn_ctx);
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return A;
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}
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BIGNUM *SRP_Calc_client_key(BIGNUM *N, BIGNUM *B, BIGNUM *g, BIGNUM *x, BIGNUM *a, BIGNUM *u)
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{
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BIGNUM *tmp = NULL, *tmp2 = NULL, *tmp3 = NULL , *k = NULL, *K = NULL;
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BN_CTX *bn_ctx;
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if (u == NULL || B == NULL || N == NULL || g == NULL || x == NULL || a == NULL ||
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(bn_ctx = BN_CTX_new()) == NULL)
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return NULL;
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if ((tmp = BN_new()) == NULL ||
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(tmp2 = BN_new())== NULL ||
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(tmp3 = BN_new())== NULL ||
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(K = BN_new()) == NULL)
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goto err;
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if (!BN_mod_exp(tmp,g,x,N,bn_ctx))
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goto err;
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if (!(k = srp_Calc_k(N,g)))
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goto err;
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if (!BN_mod_mul(tmp2,tmp,k,N,bn_ctx))
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goto err;
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if (!BN_mod_sub(tmp,B,tmp2,N,bn_ctx))
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goto err;
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if (!BN_mod_mul(tmp3,u,x,N,bn_ctx))
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goto err;
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if (!BN_mod_add(tmp2,a,tmp3,N,bn_ctx))
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goto err;
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if (!BN_mod_exp(K,tmp,tmp2,N,bn_ctx))
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goto err;
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err :
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BN_CTX_free(bn_ctx);
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BN_clear_free(tmp);
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BN_clear_free(tmp2);
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BN_clear_free(tmp3);
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BN_free(k);
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return K;
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}
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int SRP_Verify_B_mod_N(BIGNUM *B, BIGNUM *N)
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{
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BIGNUM *r;
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BN_CTX *bn_ctx;
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int ret = 0;
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if (B == NULL || N == NULL ||
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(bn_ctx = BN_CTX_new()) == NULL)
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return 0;
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if ((r = BN_new()) == NULL)
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goto err;
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/* Checks if B % N == 0 */
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if (!BN_nnmod(r,B,N,bn_ctx))
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goto err;
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ret = !BN_is_zero(r);
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err:
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BN_CTX_free(bn_ctx);
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BN_free(r);
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return ret;
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}
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int SRP_Verify_A_mod_N(BIGNUM *A, BIGNUM *N)
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{
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/* Checks if A % N == 0 */
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return SRP_Verify_B_mod_N(A,N) ;
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}
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/* Check if G and N are kwown parameters.
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The values have been generated from the ietf-tls-srp draft version 8
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*/
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char * SRP_check_known_gN_param(BIGNUM* g, BIGNUM* N)
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{
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size_t i;
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if ((g == NULL) || (N == NULL))
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return 0;
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srp_bn_print(g);
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srp_bn_print(N);
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for(i = 0; i < KNOWN_GN_NUMBER; i++)
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{
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if (BN_cmp(knowngN[i].g, g) == 0 && BN_cmp(knowngN[i].N, N) == 0)
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return knowngN[i].id;
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}
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return NULL;
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}
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SRP_gN *SRP_get_default_gN(const char *id)
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{
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size_t i;
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if (id == NULL)
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return knowngN;
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for(i = 0; i < KNOWN_GN_NUMBER; i++)
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{
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if (strcmp(knowngN[i].id, id)==0)
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return knowngN + i;
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}
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return NULL;
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}
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#endif
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