959 lines
31 KiB
C
959 lines
31 KiB
C
/* crypto/rsa/rsa_eay.c */
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/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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* All rights reserved.
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*
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* This package is an SSL implementation written
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* by Eric Young (eay@cryptsoft.com).
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* The implementation was written so as to conform with Netscapes SSL.
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*
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* This library is free for commercial and non-commercial use as long as
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* the following conditions are aheared to. The following conditions
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* apply to all code found in this distribution, be it the RC4, RSA,
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* lhash, DES, etc., code; not just the SSL code. The SSL documentation
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* included with this distribution is covered by the same copyright terms
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* except that the holder is Tim Hudson (tjh@cryptsoft.com).
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*
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* Copyright remains Eric Young's, and as such any Copyright notices in
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* the code are not to be removed.
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* If this package is used in a product, Eric Young should be given attribution
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* as the author of the parts of the library used.
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* This can be in the form of a textual message at program startup or
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* in documentation (online or textual) provided with the package.
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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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* 1. Redistributions of source code must retain the copyright
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* notice, this list of conditions and the following disclaimer.
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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 the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* "This product includes cryptographic software written by
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* Eric Young (eay@cryptsoft.com)"
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* The word 'cryptographic' can be left out if the rouines from the library
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* being used are not cryptographic related :-).
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* 4. If you include any Windows specific code (or a derivative thereof) from
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* the apps directory (application code) you must include an acknowledgement:
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* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
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*
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* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* The licence and distribution terms for any publically available version or
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* derivative of this code cannot be changed. i.e. this code cannot simply be
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* copied and put under another distribution licence
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* [including the GNU Public Licence.]
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*/
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/* ====================================================================
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* Copyright (c) 1998-2019 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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* openssl-core@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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#include <stdio.h>
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#include "cryptlib.h"
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#include <openssl/bn.h>
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#include <openssl/rsa.h>
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#include <openssl/rand.h>
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#include "bn_int.h"
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#include "constant_time_locl.h"
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#ifndef RSA_NULL
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static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
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unsigned char *to, RSA *rsa, int padding);
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static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
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unsigned char *to, RSA *rsa, int padding);
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static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
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unsigned char *to, RSA *rsa, int padding);
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static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
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unsigned char *to, RSA *rsa, int padding);
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static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *i, RSA *rsa,
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BN_CTX *ctx);
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static int RSA_eay_init(RSA *rsa);
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static int RSA_eay_finish(RSA *rsa);
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static RSA_METHOD rsa_pkcs1_eay_meth = {
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"Eric Young's PKCS#1 RSA",
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RSA_eay_public_encrypt,
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RSA_eay_public_decrypt, /* signature verification */
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RSA_eay_private_encrypt, /* signing */
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RSA_eay_private_decrypt,
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RSA_eay_mod_exp,
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BN_mod_exp_mont, /* XXX probably we should not use Montgomery
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* if e == 3 */
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RSA_eay_init,
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RSA_eay_finish,
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0, /* flags */
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NULL,
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0, /* rsa_sign */
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0, /* rsa_verify */
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NULL /* rsa_keygen */
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};
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const RSA_METHOD *RSA_PKCS1_SSLeay(void)
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{
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return (&rsa_pkcs1_eay_meth);
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}
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static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
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unsigned char *to, RSA *rsa, int padding)
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{
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BIGNUM *f, *ret;
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int i, num = 0, r = -1;
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unsigned char *buf = NULL;
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BN_CTX *ctx = NULL;
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if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) {
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RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_MODULUS_TOO_LARGE);
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return -1;
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}
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if (BN_ucmp(rsa->n, rsa->e) <= 0) {
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RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE);
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return -1;
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}
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/* for large moduli, enforce exponent limit */
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if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS) {
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if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) {
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RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE);
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return -1;
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}
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}
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if ((ctx = BN_CTX_new()) == NULL)
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goto err;
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BN_CTX_start(ctx);
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f = BN_CTX_get(ctx);
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ret = BN_CTX_get(ctx);
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num = BN_num_bytes(rsa->n);
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buf = OPENSSL_malloc(num);
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if (!f || !ret || !buf) {
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RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, ERR_R_MALLOC_FAILURE);
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goto err;
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}
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switch (padding) {
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case RSA_PKCS1_PADDING:
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i = RSA_padding_add_PKCS1_type_2(buf, num, from, flen);
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break;
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# ifndef OPENSSL_NO_SHA
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case RSA_PKCS1_OAEP_PADDING:
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i = RSA_padding_add_PKCS1_OAEP(buf, num, from, flen, NULL, 0);
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break;
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# endif
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case RSA_SSLV23_PADDING:
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i = RSA_padding_add_SSLv23(buf, num, from, flen);
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break;
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case RSA_NO_PADDING:
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i = RSA_padding_add_none(buf, num, from, flen);
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break;
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default:
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RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_UNKNOWN_PADDING_TYPE);
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goto err;
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}
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if (i <= 0)
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goto err;
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if (BN_bin2bn(buf, num, f) == NULL)
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goto err;
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if (BN_ucmp(f, rsa->n) >= 0) {
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/* usually the padding functions would catch this */
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RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,
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RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
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goto err;
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}
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if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
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if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, CRYPTO_LOCK_RSA,
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rsa->n, ctx))
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goto err;
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if (!rsa->meth->bn_mod_exp(ret, f, rsa->e, rsa->n, ctx,
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rsa->_method_mod_n))
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goto err;
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/*
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* BN_bn2binpad puts in leading 0 bytes if the number is less than
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* the length of the modulus.
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*/
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r = bn_bn2binpad(ret, to, num);
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err:
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if (ctx != NULL) {
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BN_CTX_end(ctx);
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BN_CTX_free(ctx);
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}
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if (buf != NULL) {
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OPENSSL_cleanse(buf, num);
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OPENSSL_free(buf);
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}
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return (r);
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}
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static BN_BLINDING *rsa_get_blinding(RSA *rsa, int *local, BN_CTX *ctx)
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{
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BN_BLINDING *ret;
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int got_write_lock = 0;
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CRYPTO_THREADID cur;
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CRYPTO_r_lock(CRYPTO_LOCK_RSA);
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if (rsa->blinding == NULL) {
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CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
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CRYPTO_w_lock(CRYPTO_LOCK_RSA);
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got_write_lock = 1;
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if (rsa->blinding == NULL)
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rsa->blinding = RSA_setup_blinding(rsa, ctx);
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}
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ret = rsa->blinding;
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if (ret == NULL)
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goto err;
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CRYPTO_THREADID_current(&cur);
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if (!CRYPTO_THREADID_cmp(&cur, BN_BLINDING_thread_id(ret))) {
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/* rsa->blinding is ours! */
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*local = 1;
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} else {
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/* resort to rsa->mt_blinding instead */
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/*
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* instructs rsa_blinding_convert(), rsa_blinding_invert() that the
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* BN_BLINDING is shared, meaning that accesses require locks, and
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* that the blinding factor must be stored outside the BN_BLINDING
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*/
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*local = 0;
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if (rsa->mt_blinding == NULL) {
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if (!got_write_lock) {
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CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
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CRYPTO_w_lock(CRYPTO_LOCK_RSA);
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got_write_lock = 1;
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}
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if (rsa->mt_blinding == NULL)
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rsa->mt_blinding = RSA_setup_blinding(rsa, ctx);
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}
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ret = rsa->mt_blinding;
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}
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err:
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if (got_write_lock)
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CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
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else
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CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
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return ret;
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}
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static int rsa_blinding_convert(BN_BLINDING *b, BIGNUM *f, BIGNUM *unblind,
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BN_CTX *ctx)
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{
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if (unblind == NULL)
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/*
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* Local blinding: store the unblinding factor in BN_BLINDING.
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*/
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return BN_BLINDING_convert_ex(f, NULL, b, ctx);
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else {
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/*
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* Shared blinding: store the unblinding factor outside BN_BLINDING.
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*/
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int ret;
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CRYPTO_w_lock(CRYPTO_LOCK_RSA_BLINDING);
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ret = BN_BLINDING_convert_ex(f, unblind, b, ctx);
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CRYPTO_w_unlock(CRYPTO_LOCK_RSA_BLINDING);
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return ret;
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}
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}
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static int rsa_blinding_invert(BN_BLINDING *b, BIGNUM *f, BIGNUM *unblind,
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BN_CTX *ctx)
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{
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/*
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* For local blinding, unblind is set to NULL, and BN_BLINDING_invert_ex
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* will use the unblinding factor stored in BN_BLINDING. If BN_BLINDING
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* is shared between threads, unblind must be non-null:
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* BN_BLINDING_invert_ex will then use the local unblinding factor, and
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* will only read the modulus from BN_BLINDING. In both cases it's safe
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* to access the blinding without a lock.
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*/
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return BN_BLINDING_invert_ex(f, unblind, b, ctx);
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}
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/* signing */
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static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
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unsigned char *to, RSA *rsa, int padding)
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{
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BIGNUM *f, *ret, *res;
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int i, num = 0, r = -1;
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unsigned char *buf = NULL;
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BN_CTX *ctx = NULL;
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int local_blinding = 0;
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/*
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* Used only if the blinding structure is shared. A non-NULL unblind
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* instructs rsa_blinding_convert() and rsa_blinding_invert() to store
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* the unblinding factor outside the blinding structure.
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*/
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BIGNUM *unblind = NULL;
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BN_BLINDING *blinding = NULL;
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if ((ctx = BN_CTX_new()) == NULL)
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goto err;
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BN_CTX_start(ctx);
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f = BN_CTX_get(ctx);
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ret = BN_CTX_get(ctx);
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num = BN_num_bytes(rsa->n);
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buf = OPENSSL_malloc(num);
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if (!f || !ret || !buf) {
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RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, ERR_R_MALLOC_FAILURE);
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goto err;
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}
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switch (padding) {
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case RSA_PKCS1_PADDING:
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i = RSA_padding_add_PKCS1_type_1(buf, num, from, flen);
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break;
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case RSA_X931_PADDING:
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i = RSA_padding_add_X931(buf, num, from, flen);
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break;
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case RSA_NO_PADDING:
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i = RSA_padding_add_none(buf, num, from, flen);
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break;
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case RSA_SSLV23_PADDING:
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default:
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RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, RSA_R_UNKNOWN_PADDING_TYPE);
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goto err;
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}
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if (i <= 0)
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goto err;
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if (BN_bin2bn(buf, num, f) == NULL)
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goto err;
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if (BN_ucmp(f, rsa->n) >= 0) {
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/* usually the padding functions would catch this */
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RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,
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RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
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goto err;
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}
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if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
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if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, CRYPTO_LOCK_RSA,
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rsa->n, ctx))
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goto err;
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if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) {
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blinding = rsa_get_blinding(rsa, &local_blinding, ctx);
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if (blinding == NULL) {
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RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, ERR_R_INTERNAL_ERROR);
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goto err;
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}
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}
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if (blinding != NULL) {
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if (!local_blinding && ((unblind = BN_CTX_get(ctx)) == NULL)) {
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RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, ERR_R_MALLOC_FAILURE);
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goto err;
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}
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if (!rsa_blinding_convert(blinding, f, unblind, ctx))
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goto err;
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}
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if ((rsa->flags & RSA_FLAG_EXT_PKEY) ||
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((rsa->p != NULL) &&
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(rsa->q != NULL) &&
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(rsa->dmp1 != NULL) && (rsa->dmq1 != NULL) && (rsa->iqmp != NULL))) {
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if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx))
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goto err;
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} else {
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BIGNUM local_d;
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BIGNUM *d = NULL;
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if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
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BN_init(&local_d);
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d = &local_d;
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BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
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} else
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d = rsa->d;
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if (!rsa->meth->bn_mod_exp(ret, f, d, rsa->n, ctx,
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rsa->_method_mod_n))
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goto err;
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}
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if (blinding)
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if (!rsa_blinding_invert(blinding, ret, unblind, ctx))
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goto err;
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if (padding == RSA_X931_PADDING) {
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BN_sub(f, rsa->n, ret);
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if (BN_cmp(ret, f) > 0)
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res = f;
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else
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res = ret;
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} else
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res = ret;
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/*
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* BN_bn2binpad puts in leading 0 bytes if the number is less than
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* the length of the modulus.
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*/
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r = bn_bn2binpad(res, to, num);
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err:
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if (ctx != NULL) {
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BN_CTX_end(ctx);
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BN_CTX_free(ctx);
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}
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if (buf != NULL) {
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OPENSSL_cleanse(buf, num);
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OPENSSL_free(buf);
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}
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return (r);
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}
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|
|
|
static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
|
|
unsigned char *to, RSA *rsa, int padding)
|
|
{
|
|
BIGNUM *f, *ret;
|
|
int j, num = 0, r = -1;
|
|
unsigned char *buf = NULL;
|
|
BN_CTX *ctx = NULL;
|
|
int local_blinding = 0;
|
|
/*
|
|
* Used only if the blinding structure is shared. A non-NULL unblind
|
|
* instructs rsa_blinding_convert() and rsa_blinding_invert() to store
|
|
* the unblinding factor outside the blinding structure.
|
|
*/
|
|
BIGNUM *unblind = NULL;
|
|
BN_BLINDING *blinding = NULL;
|
|
|
|
if ((ctx = BN_CTX_new()) == NULL)
|
|
goto err;
|
|
BN_CTX_start(ctx);
|
|
f = BN_CTX_get(ctx);
|
|
ret = BN_CTX_get(ctx);
|
|
num = BN_num_bytes(rsa->n);
|
|
buf = OPENSSL_malloc(num);
|
|
if (!f || !ret || !buf) {
|
|
RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_MALLOC_FAILURE);
|
|
goto err;
|
|
}
|
|
|
|
/*
|
|
* This check was for equality but PGP does evil things and chops off the
|
|
* top '0' bytes
|
|
*/
|
|
if (flen > num) {
|
|
RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,
|
|
RSA_R_DATA_GREATER_THAN_MOD_LEN);
|
|
goto err;
|
|
}
|
|
|
|
/* make data into a big number */
|
|
if (BN_bin2bn(from, (int)flen, f) == NULL)
|
|
goto err;
|
|
|
|
if (BN_ucmp(f, rsa->n) >= 0) {
|
|
RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,
|
|
RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
|
|
goto err;
|
|
}
|
|
|
|
if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) {
|
|
blinding = rsa_get_blinding(rsa, &local_blinding, ctx);
|
|
if (blinding == NULL) {
|
|
RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_INTERNAL_ERROR);
|
|
goto err;
|
|
}
|
|
}
|
|
|
|
if (blinding != NULL) {
|
|
if (!local_blinding && ((unblind = BN_CTX_get(ctx)) == NULL)) {
|
|
RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_MALLOC_FAILURE);
|
|
goto err;
|
|
}
|
|
if (!rsa_blinding_convert(blinding, f, unblind, ctx))
|
|
goto err;
|
|
}
|
|
|
|
/* do the decrypt */
|
|
if ((rsa->flags & RSA_FLAG_EXT_PKEY) ||
|
|
((rsa->p != NULL) &&
|
|
(rsa->q != NULL) &&
|
|
(rsa->dmp1 != NULL) && (rsa->dmq1 != NULL) && (rsa->iqmp != NULL))) {
|
|
if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx))
|
|
goto err;
|
|
} else {
|
|
BIGNUM local_d;
|
|
BIGNUM *d = NULL;
|
|
|
|
if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
|
|
d = &local_d;
|
|
BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
|
|
} else
|
|
d = rsa->d;
|
|
|
|
if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
|
|
if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, CRYPTO_LOCK_RSA,
|
|
rsa->n, ctx))
|
|
goto err;
|
|
if (!rsa->meth->bn_mod_exp(ret, f, d, rsa->n, ctx,
|
|
rsa->_method_mod_n))
|
|
goto err;
|
|
}
|
|
|
|
if (blinding)
|
|
if (!rsa_blinding_invert(blinding, ret, unblind, ctx))
|
|
goto err;
|
|
|
|
j = bn_bn2binpad(ret, buf, num);
|
|
|
|
switch (padding) {
|
|
case RSA_PKCS1_PADDING:
|
|
r = RSA_padding_check_PKCS1_type_2(to, num, buf, j, num);
|
|
break;
|
|
# ifndef OPENSSL_NO_SHA
|
|
case RSA_PKCS1_OAEP_PADDING:
|
|
r = RSA_padding_check_PKCS1_OAEP(to, num, buf, j, num, NULL, 0);
|
|
break;
|
|
# endif
|
|
case RSA_SSLV23_PADDING:
|
|
r = RSA_padding_check_SSLv23(to, num, buf, j, num);
|
|
break;
|
|
case RSA_NO_PADDING:
|
|
memcpy(to, buf, (r = j));
|
|
break;
|
|
default:
|
|
RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, RSA_R_UNKNOWN_PADDING_TYPE);
|
|
goto err;
|
|
}
|
|
RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, RSA_R_PADDING_CHECK_FAILED);
|
|
err_clear_last_constant_time(1 & ~constant_time_msb(r));
|
|
|
|
err:
|
|
if (ctx != NULL) {
|
|
BN_CTX_end(ctx);
|
|
BN_CTX_free(ctx);
|
|
}
|
|
if (buf != NULL) {
|
|
OPENSSL_cleanse(buf, num);
|
|
OPENSSL_free(buf);
|
|
}
|
|
return (r);
|
|
}
|
|
|
|
/* signature verification */
|
|
static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
|
|
unsigned char *to, RSA *rsa, int padding)
|
|
{
|
|
BIGNUM *f, *ret;
|
|
int i, num = 0, r = -1;
|
|
unsigned char *buf = NULL;
|
|
BN_CTX *ctx = NULL;
|
|
|
|
if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) {
|
|
RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_MODULUS_TOO_LARGE);
|
|
return -1;
|
|
}
|
|
|
|
if (BN_ucmp(rsa->n, rsa->e) <= 0) {
|
|
RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE);
|
|
return -1;
|
|
}
|
|
|
|
/* for large moduli, enforce exponent limit */
|
|
if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS) {
|
|
if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) {
|
|
RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE);
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
if ((ctx = BN_CTX_new()) == NULL)
|
|
goto err;
|
|
BN_CTX_start(ctx);
|
|
f = BN_CTX_get(ctx);
|
|
ret = BN_CTX_get(ctx);
|
|
num = BN_num_bytes(rsa->n);
|
|
buf = OPENSSL_malloc(num);
|
|
if (!f || !ret || !buf) {
|
|
RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, ERR_R_MALLOC_FAILURE);
|
|
goto err;
|
|
}
|
|
|
|
/*
|
|
* This check was for equality but PGP does evil things and chops off the
|
|
* top '0' bytes
|
|
*/
|
|
if (flen > num) {
|
|
RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_DATA_GREATER_THAN_MOD_LEN);
|
|
goto err;
|
|
}
|
|
|
|
if (BN_bin2bn(from, flen, f) == NULL)
|
|
goto err;
|
|
|
|
if (BN_ucmp(f, rsa->n) >= 0) {
|
|
RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,
|
|
RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
|
|
goto err;
|
|
}
|
|
|
|
if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
|
|
if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, CRYPTO_LOCK_RSA,
|
|
rsa->n, ctx))
|
|
goto err;
|
|
|
|
if (!rsa->meth->bn_mod_exp(ret, f, rsa->e, rsa->n, ctx,
|
|
rsa->_method_mod_n))
|
|
goto err;
|
|
|
|
if ((padding == RSA_X931_PADDING) && ((ret->d[0] & 0xf) != 12))
|
|
if (!BN_sub(ret, rsa->n, ret))
|
|
goto err;
|
|
|
|
i = bn_bn2binpad(ret, buf, num);
|
|
|
|
switch (padding) {
|
|
case RSA_PKCS1_PADDING:
|
|
r = RSA_padding_check_PKCS1_type_1(to, num, buf, i, num);
|
|
break;
|
|
case RSA_X931_PADDING:
|
|
r = RSA_padding_check_X931(to, num, buf, i, num);
|
|
break;
|
|
case RSA_NO_PADDING:
|
|
memcpy(to, buf, (r = i));
|
|
break;
|
|
default:
|
|
RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_UNKNOWN_PADDING_TYPE);
|
|
goto err;
|
|
}
|
|
if (r < 0)
|
|
RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_PADDING_CHECK_FAILED);
|
|
|
|
err:
|
|
if (ctx != NULL) {
|
|
BN_CTX_end(ctx);
|
|
BN_CTX_free(ctx);
|
|
}
|
|
if (buf != NULL) {
|
|
OPENSSL_cleanse(buf, num);
|
|
OPENSSL_free(buf);
|
|
}
|
|
return (r);
|
|
}
|
|
|
|
static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
|
|
{
|
|
BIGNUM *r1, *m1, *vrfy;
|
|
BIGNUM local_dmp1, local_dmq1, local_c, local_r1;
|
|
BIGNUM *dmp1, *dmq1, *c, *pr1;
|
|
int ret = 0, smooth = 0;
|
|
|
|
BN_CTX_start(ctx);
|
|
r1 = BN_CTX_get(ctx);
|
|
m1 = BN_CTX_get(ctx);
|
|
vrfy = BN_CTX_get(ctx);
|
|
|
|
{
|
|
BIGNUM local_p, local_q;
|
|
BIGNUM *p = NULL, *q = NULL;
|
|
|
|
/*
|
|
* Make sure BN_mod_inverse in Montgomery intialization uses the
|
|
* BN_FLG_CONSTTIME flag (unless RSA_FLAG_NO_CONSTTIME is set)
|
|
*/
|
|
if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
|
|
BN_init(&local_p);
|
|
p = &local_p;
|
|
BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME);
|
|
|
|
BN_init(&local_q);
|
|
q = &local_q;
|
|
BN_with_flags(q, rsa->q, BN_FLG_CONSTTIME);
|
|
} else {
|
|
p = rsa->p;
|
|
q = rsa->q;
|
|
}
|
|
|
|
if (rsa->flags & RSA_FLAG_CACHE_PRIVATE) {
|
|
if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_p, CRYPTO_LOCK_RSA,
|
|
p, ctx))
|
|
goto err;
|
|
if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_q, CRYPTO_LOCK_RSA,
|
|
q, ctx))
|
|
goto err;
|
|
|
|
smooth = (rsa->meth->bn_mod_exp == BN_mod_exp_mont)
|
|
&& (BN_num_bits(q) == BN_num_bits(p));
|
|
}
|
|
}
|
|
|
|
if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
|
|
if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, CRYPTO_LOCK_RSA,
|
|
rsa->n, ctx))
|
|
goto err;
|
|
|
|
if (smooth) {
|
|
/*
|
|
* Conversion from Montgomery domain, a.k.a. Montgomery reduction,
|
|
* accepts values in [0-m*2^w) range. w is m's bit width rounded up
|
|
* to limb width. So that at the very least if |I| is fully reduced,
|
|
* i.e. less than p*q, we can count on from-to round to perform
|
|
* below modulo operations on |I|. Unlike BN_mod it's constant time.
|
|
*/
|
|
if (/* m1 = I moq q */
|
|
!bn_from_mont_fixed_top(m1, I, rsa->_method_mod_q, ctx)
|
|
|| !bn_to_mont_fixed_top(m1, m1, rsa->_method_mod_q, ctx)
|
|
/* m1 = m1^dmq1 mod q */
|
|
|| !BN_mod_exp_mont_consttime(m1, m1, rsa->dmq1, rsa->q, ctx,
|
|
rsa->_method_mod_q)
|
|
/* r1 = I mod p */
|
|
|| !bn_from_mont_fixed_top(r1, I, rsa->_method_mod_p, ctx)
|
|
|| !bn_to_mont_fixed_top(r1, r1, rsa->_method_mod_p, ctx)
|
|
/* r1 = r1^dmp1 mod p */
|
|
|| !BN_mod_exp_mont_consttime(r1, r1, rsa->dmp1, rsa->p, ctx,
|
|
rsa->_method_mod_p)
|
|
/* r1 = (r1 - m1) mod p */
|
|
/*
|
|
* bn_mod_sub_fixed_top is not regular modular subtraction,
|
|
* it can tolerate subtrahend to be larger than modulus, but
|
|
* not bit-wise wider. This makes up for uncommon q>p case,
|
|
* when |m1| can be larger than |rsa->p|.
|
|
*/
|
|
|| !bn_mod_sub_fixed_top(r1, r1, m1, rsa->p)
|
|
|
|
/* r1 = r1 * iqmp mod p */
|
|
|| !bn_to_mont_fixed_top(r1, r1, rsa->_method_mod_p, ctx)
|
|
|| !bn_mul_mont_fixed_top(r1, r1, rsa->iqmp, rsa->_method_mod_p,
|
|
ctx)
|
|
/* r0 = r1 * q + m1 */
|
|
|| !bn_mul_fixed_top(r0, r1, rsa->q, ctx)
|
|
|| !bn_mod_add_fixed_top(r0, r0, m1, rsa->n))
|
|
goto err;
|
|
|
|
goto tail;
|
|
}
|
|
|
|
/* compute I mod q */
|
|
if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
|
|
c = &local_c;
|
|
BN_with_flags(c, I, BN_FLG_CONSTTIME);
|
|
if (!BN_mod(r1, c, rsa->q, ctx))
|
|
goto err;
|
|
} else {
|
|
if (!BN_mod(r1, I, rsa->q, ctx))
|
|
goto err;
|
|
}
|
|
|
|
/* compute r1^dmq1 mod q */
|
|
if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
|
|
dmq1 = &local_dmq1;
|
|
BN_with_flags(dmq1, rsa->dmq1, BN_FLG_CONSTTIME);
|
|
} else
|
|
dmq1 = rsa->dmq1;
|
|
if (!rsa->meth->bn_mod_exp(m1, r1, dmq1, rsa->q, ctx, rsa->_method_mod_q))
|
|
goto err;
|
|
|
|
/* compute I mod p */
|
|
if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
|
|
c = &local_c;
|
|
BN_with_flags(c, I, BN_FLG_CONSTTIME);
|
|
if (!BN_mod(r1, c, rsa->p, ctx))
|
|
goto err;
|
|
} else {
|
|
if (!BN_mod(r1, I, rsa->p, ctx))
|
|
goto err;
|
|
}
|
|
|
|
/* compute r1^dmp1 mod p */
|
|
if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
|
|
dmp1 = &local_dmp1;
|
|
BN_with_flags(dmp1, rsa->dmp1, BN_FLG_CONSTTIME);
|
|
} else
|
|
dmp1 = rsa->dmp1;
|
|
if (!rsa->meth->bn_mod_exp(r0, r1, dmp1, rsa->p, ctx, rsa->_method_mod_p))
|
|
goto err;
|
|
|
|
if (!BN_sub(r0, r0, m1))
|
|
goto err;
|
|
/*
|
|
* This will help stop the size of r0 increasing, which does affect the
|
|
* multiply if it optimised for a power of 2 size
|
|
*/
|
|
if (BN_is_negative(r0))
|
|
if (!BN_add(r0, r0, rsa->p))
|
|
goto err;
|
|
|
|
if (!BN_mul(r1, r0, rsa->iqmp, ctx))
|
|
goto err;
|
|
|
|
/* Turn BN_FLG_CONSTTIME flag on before division operation */
|
|
if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
|
|
pr1 = &local_r1;
|
|
BN_with_flags(pr1, r1, BN_FLG_CONSTTIME);
|
|
} else
|
|
pr1 = r1;
|
|
if (!BN_mod(r0, pr1, rsa->p, ctx))
|
|
goto err;
|
|
|
|
/*
|
|
* If p < q it is occasionally possible for the correction of adding 'p'
|
|
* if r0 is negative above to leave the result still negative. This can
|
|
* break the private key operations: the following second correction
|
|
* should *always* correct this rare occurrence. This will *never* happen
|
|
* with OpenSSL generated keys because they ensure p > q [steve]
|
|
*/
|
|
if (BN_is_negative(r0))
|
|
if (!BN_add(r0, r0, rsa->p))
|
|
goto err;
|
|
if (!BN_mul(r1, r0, rsa->q, ctx))
|
|
goto err;
|
|
if (!BN_add(r0, r1, m1))
|
|
goto err;
|
|
|
|
tail:
|
|
if (rsa->e && rsa->n) {
|
|
if (rsa->meth->bn_mod_exp == BN_mod_exp_mont) {
|
|
if (!BN_mod_exp_mont(vrfy, r0, rsa->e, rsa->n, ctx,
|
|
rsa->_method_mod_n))
|
|
goto err;
|
|
} else {
|
|
bn_correct_top(r0);
|
|
if (!rsa->meth->bn_mod_exp(vrfy, r0, rsa->e, rsa->n, ctx,
|
|
rsa->_method_mod_n))
|
|
goto err;
|
|
}
|
|
/*
|
|
* If 'I' was greater than (or equal to) rsa->n, the operation will
|
|
* be equivalent to using 'I mod n'. However, the result of the
|
|
* verify will *always* be less than 'n' so we don't check for
|
|
* absolute equality, just congruency.
|
|
*/
|
|
if (!BN_sub(vrfy, vrfy, I))
|
|
goto err;
|
|
if (BN_is_zero(vrfy)) {
|
|
bn_correct_top(r0);
|
|
ret = 1;
|
|
goto err; /* not actually error */
|
|
}
|
|
if (!BN_mod(vrfy, vrfy, rsa->n, ctx))
|
|
goto err;
|
|
if (BN_is_negative(vrfy))
|
|
if (!BN_add(vrfy, vrfy, rsa->n))
|
|
goto err;
|
|
if (!BN_is_zero(vrfy)) {
|
|
/*
|
|
* 'I' and 'vrfy' aren't congruent mod n. Don't leak
|
|
* miscalculated CRT output, just do a raw (slower) mod_exp and
|
|
* return that instead.
|
|
*/
|
|
|
|
BIGNUM local_d;
|
|
BIGNUM *d = NULL;
|
|
|
|
if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
|
|
d = &local_d;
|
|
BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
|
|
} else
|
|
d = rsa->d;
|
|
if (!rsa->meth->bn_mod_exp(r0, I, d, rsa->n, ctx,
|
|
rsa->_method_mod_n))
|
|
goto err;
|
|
}
|
|
}
|
|
/*
|
|
* It's unfortunate that we have to bn_correct_top(r0). What hopefully
|
|
* saves the day is that correction is highly unlike, and private key
|
|
* operations are customarily performed on blinded message. Which means
|
|
* that attacker won't observe correlation with chosen plaintext.
|
|
* Secondly, remaining code would still handle it in same computational
|
|
* time and even conceal memory access pattern around corrected top.
|
|
*/
|
|
bn_correct_top(r0);
|
|
ret = 1;
|
|
err:
|
|
BN_CTX_end(ctx);
|
|
return (ret);
|
|
}
|
|
|
|
static int RSA_eay_init(RSA *rsa)
|
|
{
|
|
rsa->flags |= RSA_FLAG_CACHE_PUBLIC | RSA_FLAG_CACHE_PRIVATE;
|
|
return (1);
|
|
}
|
|
|
|
static int RSA_eay_finish(RSA *rsa)
|
|
{
|
|
if (rsa->_method_mod_n != NULL)
|
|
BN_MONT_CTX_free(rsa->_method_mod_n);
|
|
if (rsa->_method_mod_p != NULL)
|
|
BN_MONT_CTX_free(rsa->_method_mod_p);
|
|
if (rsa->_method_mod_q != NULL)
|
|
BN_MONT_CTX_free(rsa->_method_mod_q);
|
|
return (1);
|
|
}
|
|
|
|
#endif
|