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976 lines
29 KiB
C
976 lines
29 KiB
C
/*
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* Copyright 1995-2019 The OpenSSL Project Authors. All Rights Reserved.
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*
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* Licensed under the OpenSSL license (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://www.openssl.org/source/license.html
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*/
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#include "internal/cryptlib.h"
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#include "crypto/bn.h"
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#include "rsa_local.h"
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#include "internal/constant_time.h"
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static int rsa_ossl_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_ossl_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_ossl_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_ossl_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_ossl_mod_exp(BIGNUM *r0, const BIGNUM *i, RSA *rsa,
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BN_CTX *ctx);
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static int rsa_ossl_init(RSA *rsa);
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static int rsa_ossl_finish(RSA *rsa);
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static RSA_METHOD rsa_pkcs1_ossl_meth = {
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"OpenSSL PKCS#1 RSA",
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rsa_ossl_public_encrypt,
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rsa_ossl_public_decrypt, /* signature verification */
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rsa_ossl_private_encrypt, /* signing */
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rsa_ossl_private_decrypt,
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rsa_ossl_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_ossl_init,
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rsa_ossl_finish,
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RSA_FLAG_FIPS_METHOD, /* 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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NULL /* rsa_multi_prime_keygen */
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};
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static const RSA_METHOD *default_RSA_meth = &rsa_pkcs1_ossl_meth;
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void RSA_set_default_method(const RSA_METHOD *meth)
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{
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default_RSA_meth = meth;
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}
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const RSA_METHOD *RSA_get_default_method(void)
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{
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return default_RSA_meth;
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}
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const RSA_METHOD *RSA_PKCS1_OpenSSL(void)
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{
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return &rsa_pkcs1_ossl_meth;
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}
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const RSA_METHOD *RSA_null_method(void)
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{
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return NULL;
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}
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static int rsa_ossl_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_OSSL_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_OSSL_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_OSSL_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 (ret == NULL || buf == NULL) {
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RSAerr(RSA_F_RSA_OSSL_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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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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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_OSSL_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_OSSL_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, rsa->lock,
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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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BN_CTX_end(ctx);
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BN_CTX_free(ctx);
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OPENSSL_clear_free(buf, num);
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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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CRYPTO_THREAD_write_lock(rsa->lock);
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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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if (BN_BLINDING_is_current_thread(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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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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CRYPTO_THREAD_unlock(rsa->lock);
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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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BN_BLINDING_lock(b);
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ret = BN_BLINDING_convert_ex(f, unblind, b, ctx);
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BN_BLINDING_unlock(b);
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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_ossl_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 (ret == NULL || buf == NULL) {
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RSAerr(RSA_F_RSA_OSSL_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_OSSL_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_OSSL_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, rsa->lock,
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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_OSSL_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_OSSL_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->version == RSA_ASN1_VERSION_MULTI) ||
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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 *d = BN_new();
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if (d == NULL) {
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RSAerr(RSA_F_RSA_OSSL_PRIVATE_ENCRYPT, ERR_R_MALLOC_FAILURE);
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goto err;
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}
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if (rsa->d == NULL) {
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RSAerr(RSA_F_RSA_OSSL_PRIVATE_ENCRYPT, RSA_R_MISSING_PRIVATE_KEY);
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BN_free(d);
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goto err;
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}
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BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
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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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BN_free(d);
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goto err;
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}
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/* We MUST free d before any further use of rsa->d */
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BN_free(d);
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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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if (!BN_sub(f, rsa->n, ret))
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goto err;
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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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/*
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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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BN_CTX_end(ctx);
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BN_CTX_free(ctx);
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OPENSSL_clear_free(buf, num);
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return r;
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}
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static int rsa_ossl_private_decrypt(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 j, 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 (ret == NULL || buf == NULL) {
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RSAerr(RSA_F_RSA_OSSL_PRIVATE_DECRYPT, ERR_R_MALLOC_FAILURE);
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goto err;
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}
|
|
|
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/*
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* This check was for equality but PGP does evil things and chops off the
|
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* top '0' bytes
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*/
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if (flen > num) {
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RSAerr(RSA_F_RSA_OSSL_PRIVATE_DECRYPT,
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RSA_R_DATA_GREATER_THAN_MOD_LEN);
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goto err;
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}
|
|
|
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/* make data into a big number */
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if (BN_bin2bn(from, (int)flen, f) == NULL)
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goto err;
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|
|
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if (BN_ucmp(f, rsa->n) >= 0) {
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RSAerr(RSA_F_RSA_OSSL_PRIVATE_DECRYPT,
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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_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_OSSL_PRIVATE_DECRYPT, ERR_R_INTERNAL_ERROR);
|
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goto err;
|
|
}
|
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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_OSSL_PRIVATE_DECRYPT, 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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/* do the decrypt */
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if ((rsa->flags & RSA_FLAG_EXT_PKEY) ||
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(rsa->version == RSA_ASN1_VERSION_MULTI) ||
|
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((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))
|
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goto err;
|
|
} else {
|
|
BIGNUM *d = BN_new();
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|
if (d == NULL) {
|
|
RSAerr(RSA_F_RSA_OSSL_PRIVATE_DECRYPT, ERR_R_MALLOC_FAILURE);
|
|
goto err;
|
|
}
|
|
if (rsa->d == NULL) {
|
|
RSAerr(RSA_F_RSA_OSSL_PRIVATE_DECRYPT, RSA_R_MISSING_PRIVATE_KEY);
|
|
BN_free(d);
|
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goto err;
|
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}
|
|
BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
|
|
|
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if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
|
|
if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, rsa->lock,
|
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rsa->n, ctx)) {
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|
BN_free(d);
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goto err;
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|
}
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|
if (!rsa->meth->bn_mod_exp(ret, f, d, rsa->n, ctx,
|
|
rsa->_method_mod_n)) {
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|
BN_free(d);
|
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goto err;
|
|
}
|
|
/* We MUST free d before any further use of rsa->d */
|
|
BN_free(d);
|
|
}
|
|
|
|
if (blinding)
|
|
if (!rsa_blinding_invert(blinding, ret, unblind, ctx))
|
|
goto err;
|
|
|
|
j = BN_bn2binpad(ret, buf, num);
|
|
|
|
switch (padding) {
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|
case RSA_PKCS1_PADDING:
|
|
r = RSA_padding_check_PKCS1_type_2(to, num, buf, j, num);
|
|
break;
|
|
case RSA_PKCS1_OAEP_PADDING:
|
|
r = RSA_padding_check_PKCS1_OAEP(to, num, buf, j, num, NULL, 0);
|
|
break;
|
|
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_OSSL_PRIVATE_DECRYPT, RSA_R_UNKNOWN_PADDING_TYPE);
|
|
goto err;
|
|
}
|
|
RSAerr(RSA_F_RSA_OSSL_PRIVATE_DECRYPT, RSA_R_PADDING_CHECK_FAILED);
|
|
err_clear_last_constant_time(1 & ~constant_time_msb(r));
|
|
|
|
err:
|
|
BN_CTX_end(ctx);
|
|
BN_CTX_free(ctx);
|
|
OPENSSL_clear_free(buf, num);
|
|
return r;
|
|
}
|
|
|
|
/* signature verification */
|
|
static int rsa_ossl_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_OSSL_PUBLIC_DECRYPT, RSA_R_MODULUS_TOO_LARGE);
|
|
return -1;
|
|
}
|
|
|
|
if (BN_ucmp(rsa->n, rsa->e) <= 0) {
|
|
RSAerr(RSA_F_RSA_OSSL_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_OSSL_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 (ret == NULL || buf == NULL) {
|
|
RSAerr(RSA_F_RSA_OSSL_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_OSSL_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_OSSL_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, rsa->lock,
|
|
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) && ((bn_get_words(ret)[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_OSSL_PUBLIC_DECRYPT, RSA_R_UNKNOWN_PADDING_TYPE);
|
|
goto err;
|
|
}
|
|
if (r < 0)
|
|
RSAerr(RSA_F_RSA_OSSL_PUBLIC_DECRYPT, RSA_R_PADDING_CHECK_FAILED);
|
|
|
|
err:
|
|
BN_CTX_end(ctx);
|
|
BN_CTX_free(ctx);
|
|
OPENSSL_clear_free(buf, num);
|
|
return r;
|
|
}
|
|
|
|
static int rsa_ossl_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
|
|
{
|
|
BIGNUM *r1, *m1, *vrfy, *r2, *m[RSA_MAX_PRIME_NUM - 2];
|
|
int ret = 0, i, ex_primes = 0, smooth = 0;
|
|
RSA_PRIME_INFO *pinfo;
|
|
|
|
BN_CTX_start(ctx);
|
|
|
|
r1 = BN_CTX_get(ctx);
|
|
r2 = BN_CTX_get(ctx);
|
|
m1 = BN_CTX_get(ctx);
|
|
vrfy = BN_CTX_get(ctx);
|
|
if (vrfy == NULL)
|
|
goto err;
|
|
|
|
if (rsa->version == RSA_ASN1_VERSION_MULTI
|
|
&& ((ex_primes = sk_RSA_PRIME_INFO_num(rsa->prime_infos)) <= 0
|
|
|| ex_primes > RSA_MAX_PRIME_NUM - 2))
|
|
goto err;
|
|
|
|
if (rsa->flags & RSA_FLAG_CACHE_PRIVATE) {
|
|
BIGNUM *factor = BN_new();
|
|
|
|
if (factor == NULL)
|
|
goto err;
|
|
|
|
/*
|
|
* Make sure BN_mod_inverse in Montgomery initialization uses the
|
|
* BN_FLG_CONSTTIME flag
|
|
*/
|
|
if (!(BN_with_flags(factor, rsa->p, BN_FLG_CONSTTIME),
|
|
BN_MONT_CTX_set_locked(&rsa->_method_mod_p, rsa->lock,
|
|
factor, ctx))
|
|
|| !(BN_with_flags(factor, rsa->q, BN_FLG_CONSTTIME),
|
|
BN_MONT_CTX_set_locked(&rsa->_method_mod_q, rsa->lock,
|
|
factor, ctx))) {
|
|
BN_free(factor);
|
|
goto err;
|
|
}
|
|
for (i = 0; i < ex_primes; i++) {
|
|
pinfo = sk_RSA_PRIME_INFO_value(rsa->prime_infos, i);
|
|
BN_with_flags(factor, pinfo->r, BN_FLG_CONSTTIME);
|
|
if (!BN_MONT_CTX_set_locked(&pinfo->m, rsa->lock, factor, ctx)) {
|
|
BN_free(factor);
|
|
goto err;
|
|
}
|
|
}
|
|
/*
|
|
* We MUST free |factor| before any further use of the prime factors
|
|
*/
|
|
BN_free(factor);
|
|
|
|
smooth = (ex_primes == 0)
|
|
&& (rsa->meth->bn_mod_exp == BN_mod_exp_mont)
|
|
&& (BN_num_bits(rsa->q) == BN_num_bits(rsa->p));
|
|
}
|
|
|
|
if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
|
|
if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, rsa->lock,
|
|
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 */
|
|
{
|
|
BIGNUM *c = BN_new();
|
|
if (c == NULL)
|
|
goto err;
|
|
BN_with_flags(c, I, BN_FLG_CONSTTIME);
|
|
|
|
if (!BN_mod(r1, c, rsa->q, ctx)) {
|
|
BN_free(c);
|
|
goto err;
|
|
}
|
|
|
|
{
|
|
BIGNUM *dmq1 = BN_new();
|
|
if (dmq1 == NULL) {
|
|
BN_free(c);
|
|
goto err;
|
|
}
|
|
BN_with_flags(dmq1, rsa->dmq1, BN_FLG_CONSTTIME);
|
|
|
|
/* compute r1^dmq1 mod q */
|
|
if (!rsa->meth->bn_mod_exp(m1, r1, dmq1, rsa->q, ctx,
|
|
rsa->_method_mod_q)) {
|
|
BN_free(c);
|
|
BN_free(dmq1);
|
|
goto err;
|
|
}
|
|
/* We MUST free dmq1 before any further use of rsa->dmq1 */
|
|
BN_free(dmq1);
|
|
}
|
|
|
|
/* compute I mod p */
|
|
if (!BN_mod(r1, c, rsa->p, ctx)) {
|
|
BN_free(c);
|
|
goto err;
|
|
}
|
|
/* We MUST free c before any further use of I */
|
|
BN_free(c);
|
|
}
|
|
|
|
{
|
|
BIGNUM *dmp1 = BN_new();
|
|
if (dmp1 == NULL)
|
|
goto err;
|
|
BN_with_flags(dmp1, rsa->dmp1, BN_FLG_CONSTTIME);
|
|
|
|
/* compute r1^dmp1 mod p */
|
|
if (!rsa->meth->bn_mod_exp(r0, r1, dmp1, rsa->p, ctx,
|
|
rsa->_method_mod_p)) {
|
|
BN_free(dmp1);
|
|
goto err;
|
|
}
|
|
/* We MUST free dmp1 before any further use of rsa->dmp1 */
|
|
BN_free(dmp1);
|
|
}
|
|
|
|
/*
|
|
* calculate m_i in multi-prime case
|
|
*
|
|
* TODO:
|
|
* 1. squash the following two loops and calculate |m_i| there.
|
|
* 2. remove cc and reuse |c|.
|
|
* 3. remove |dmq1| and |dmp1| in previous block and use |di|.
|
|
*
|
|
* If these things are done, the code will be more readable.
|
|
*/
|
|
if (ex_primes > 0) {
|
|
BIGNUM *di = BN_new(), *cc = BN_new();
|
|
|
|
if (cc == NULL || di == NULL) {
|
|
BN_free(cc);
|
|
BN_free(di);
|
|
goto err;
|
|
}
|
|
|
|
for (i = 0; i < ex_primes; i++) {
|
|
/* prepare m_i */
|
|
if ((m[i] = BN_CTX_get(ctx)) == NULL) {
|
|
BN_free(cc);
|
|
BN_free(di);
|
|
goto err;
|
|
}
|
|
|
|
pinfo = sk_RSA_PRIME_INFO_value(rsa->prime_infos, i);
|
|
|
|
/* prepare c and d_i */
|
|
BN_with_flags(cc, I, BN_FLG_CONSTTIME);
|
|
BN_with_flags(di, pinfo->d, BN_FLG_CONSTTIME);
|
|
|
|
if (!BN_mod(r1, cc, pinfo->r, ctx)) {
|
|
BN_free(cc);
|
|
BN_free(di);
|
|
goto err;
|
|
}
|
|
/* compute r1 ^ d_i mod r_i */
|
|
if (!rsa->meth->bn_mod_exp(m[i], r1, di, pinfo->r, ctx, pinfo->m)) {
|
|
BN_free(cc);
|
|
BN_free(di);
|
|
goto err;
|
|
}
|
|
}
|
|
|
|
BN_free(cc);
|
|
BN_free(di);
|
|
}
|
|
|
|
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;
|
|
|
|
{
|
|
BIGNUM *pr1 = BN_new();
|
|
if (pr1 == NULL)
|
|
goto err;
|
|
BN_with_flags(pr1, r1, BN_FLG_CONSTTIME);
|
|
|
|
if (!BN_mod(r0, pr1, rsa->p, ctx)) {
|
|
BN_free(pr1);
|
|
goto err;
|
|
}
|
|
/* We MUST free pr1 before any further use of r1 */
|
|
BN_free(pr1);
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
|
|
/* add m_i to m in multi-prime case */
|
|
if (ex_primes > 0) {
|
|
BIGNUM *pr2 = BN_new();
|
|
|
|
if (pr2 == NULL)
|
|
goto err;
|
|
|
|
for (i = 0; i < ex_primes; i++) {
|
|
pinfo = sk_RSA_PRIME_INFO_value(rsa->prime_infos, i);
|
|
if (!BN_sub(r1, m[i], r0)) {
|
|
BN_free(pr2);
|
|
goto err;
|
|
}
|
|
|
|
if (!BN_mul(r2, r1, pinfo->t, ctx)) {
|
|
BN_free(pr2);
|
|
goto err;
|
|
}
|
|
|
|
BN_with_flags(pr2, r2, BN_FLG_CONSTTIME);
|
|
|
|
if (!BN_mod(r1, pr2, pinfo->r, ctx)) {
|
|
BN_free(pr2);
|
|
goto err;
|
|
}
|
|
|
|
if (BN_is_negative(r1))
|
|
if (!BN_add(r1, r1, pinfo->r)) {
|
|
BN_free(pr2);
|
|
goto err;
|
|
}
|
|
if (!BN_mul(r1, r1, pinfo->pp, ctx)) {
|
|
BN_free(pr2);
|
|
goto err;
|
|
}
|
|
if (!BN_add(r0, r0, r1)) {
|
|
BN_free(pr2);
|
|
goto err;
|
|
}
|
|
}
|
|
BN_free(pr2);
|
|
}
|
|
|
|
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 *d = BN_new();
|
|
if (d == NULL)
|
|
goto err;
|
|
BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
|
|
|
|
if (!rsa->meth->bn_mod_exp(r0, I, d, rsa->n, ctx,
|
|
rsa->_method_mod_n)) {
|
|
BN_free(d);
|
|
goto err;
|
|
}
|
|
/* We MUST free d before any further use of rsa->d */
|
|
BN_free(d);
|
|
}
|
|
}
|
|
/*
|
|
* 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_ossl_init(RSA *rsa)
|
|
{
|
|
rsa->flags |= RSA_FLAG_CACHE_PUBLIC | RSA_FLAG_CACHE_PRIVATE;
|
|
return 1;
|
|
}
|
|
|
|
static int rsa_ossl_finish(RSA *rsa)
|
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{
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int i;
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RSA_PRIME_INFO *pinfo;
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BN_MONT_CTX_free(rsa->_method_mod_n);
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BN_MONT_CTX_free(rsa->_method_mod_p);
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BN_MONT_CTX_free(rsa->_method_mod_q);
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for (i = 0; i < sk_RSA_PRIME_INFO_num(rsa->prime_infos); i++) {
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pinfo = sk_RSA_PRIME_INFO_value(rsa->prime_infos, i);
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BN_MONT_CTX_free(pinfo->m);
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}
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return 1;
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}
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