/* $OpenBSD: rsa_eay.c,v 1.56 2022/12/26 07:18:52 jmc Exp $ */ /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * * This package is an SSL implementation written * by Eric Young (eay@cryptsoft.com). * The implementation was written so as to conform with Netscapes SSL. * * This library is free for commercial and non-commercial use as long as * the following conditions are aheared to. The following conditions * apply to all code found in this distribution, be it the RC4, RSA, * lhash, DES, etc., code; not just the SSL code. The SSL documentation * included with this distribution is covered by the same copyright terms * except that the holder is Tim Hudson (tjh@cryptsoft.com). * * Copyright remains Eric Young's, and as such any Copyright notices in * the code are not to be removed. * If this package is used in a product, Eric Young should be given attribution * as the author of the parts of the library used. * This can be in the form of a textual message at program startup or * in documentation (online or textual) provided with the package. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * "This product includes cryptographic software written by * Eric Young (eay@cryptsoft.com)" * The word 'cryptographic' can be left out if the rouines from the library * being used are not cryptographic related :-). * 4. If you include any Windows specific code (or a derivative thereof) from * the apps directory (application code) you must include an acknowledgement: * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" * * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * The licence and distribution terms for any publically available version or * derivative of this code cannot be changed. i.e. this code cannot simply be * copied and put under another distribution licence * [including the GNU Public Licence.] */ /* ==================================================================== * Copyright (c) 1998-2006 The OpenSSL Project. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. All advertising materials mentioning features or use of this * software must display the following acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" * * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to * endorse or promote products derived from this software without * prior written permission. For written permission, please contact * openssl-core@openssl.org. * * 5. Products derived from this software may not be called "OpenSSL" * nor may "OpenSSL" appear in their names without prior written * permission of the OpenSSL Project. * * 6. Redistributions of any form whatsoever must retain the following * acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit (http://www.openssl.org/)" * * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED * OF THE POSSIBILITY OF SUCH DAMAGE. * ==================================================================== * * This product includes cryptographic software written by Eric Young * (eay@cryptsoft.com). This product includes software written by Tim * Hudson (tjh@cryptsoft.com). * */ #include #include #include #include #include #include #include "bn_local.h" #include "rsa_local.h" static int RSA_eay_public_encrypt(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, int padding); static int RSA_eay_private_encrypt(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, int padding); static int RSA_eay_public_decrypt(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, int padding); static int RSA_eay_private_decrypt(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, int padding); static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *i, RSA *rsa, BN_CTX *ctx); static int RSA_eay_init(RSA *rsa); static int RSA_eay_finish(RSA *rsa); static RSA_METHOD rsa_pkcs1_eay_meth = { .name = "Eric Young's PKCS#1 RSA", .rsa_pub_enc = RSA_eay_public_encrypt, .rsa_pub_dec = RSA_eay_public_decrypt, /* signature verification */ .rsa_priv_enc = RSA_eay_private_encrypt, /* signing */ .rsa_priv_dec = RSA_eay_private_decrypt, .rsa_mod_exp = RSA_eay_mod_exp, .bn_mod_exp = BN_mod_exp_mont_ct, /* XXX probably we should not use Montgomery if e == 3 */ .init = RSA_eay_init, .finish = RSA_eay_finish, }; const RSA_METHOD * RSA_PKCS1_OpenSSL(void) { return &rsa_pkcs1_eay_meth; } const RSA_METHOD * RSA_PKCS1_SSLeay(void) { return &rsa_pkcs1_eay_meth; } static int RSA_eay_public_encrypt(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, int padding) { BIGNUM *f, *ret; int i, j, k, num = 0, r = -1; unsigned char *buf = NULL; BN_CTX *ctx = NULL; if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) { RSAerror(RSA_R_MODULUS_TOO_LARGE); return -1; } if (BN_ucmp(rsa->n, rsa->e) <= 0) { RSAerror(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) { RSAerror(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 = malloc(num); if (f == NULL || ret == NULL || buf == NULL) { RSAerror(ERR_R_MALLOC_FAILURE); goto err; } switch (padding) { case RSA_PKCS1_PADDING: i = RSA_padding_add_PKCS1_type_2(buf, num, from, flen); break; #ifndef OPENSSL_NO_SHA case RSA_PKCS1_OAEP_PADDING: i = RSA_padding_add_PKCS1_OAEP(buf, num, from, flen, NULL, 0); break; #endif case RSA_NO_PADDING: i = RSA_padding_add_none(buf, num, from, flen); break; default: RSAerror(RSA_R_UNKNOWN_PADDING_TYPE); goto err; } if (i <= 0) goto err; if (BN_bin2bn(buf, num, f) == NULL) goto err; if (BN_ucmp(f, rsa->n) >= 0) { /* usually the padding functions would catch this */ RSAerror(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; /* put in leading 0 bytes if the number is less than the * length of the modulus */ j = BN_num_bytes(ret); i = BN_bn2bin(ret, &(to[num - j])); for (k = 0; k < num - i; k++) to[k] = 0; r = num; err: if (ctx != NULL) { BN_CTX_end(ctx); BN_CTX_free(ctx); } freezero(buf, num); return r; } static BN_BLINDING * rsa_get_blinding(RSA *rsa, int *local, BN_CTX *ctx) { BN_BLINDING *ret; int got_write_lock = 0; CRYPTO_THREADID cur; CRYPTO_r_lock(CRYPTO_LOCK_RSA); if (rsa->blinding == NULL) { CRYPTO_r_unlock(CRYPTO_LOCK_RSA); CRYPTO_w_lock(CRYPTO_LOCK_RSA); got_write_lock = 1; if (rsa->blinding == NULL) rsa->blinding = RSA_setup_blinding(rsa, ctx); } ret = rsa->blinding; if (ret == NULL) goto err; CRYPTO_THREADID_current(&cur); if (!CRYPTO_THREADID_cmp(&cur, BN_BLINDING_thread_id(ret))) { /* rsa->blinding is ours! */ *local = 1; } else { /* resort to rsa->mt_blinding instead */ /* * Instruct rsa_blinding_convert(), rsa_blinding_invert() * that the BN_BLINDING is shared, meaning that accesses * require locks, and that the blinding factor must be * stored outside the BN_BLINDING */ *local = 0; if (rsa->mt_blinding == NULL) { if (!got_write_lock) { CRYPTO_r_unlock(CRYPTO_LOCK_RSA); CRYPTO_w_lock(CRYPTO_LOCK_RSA); got_write_lock = 1; } if (rsa->mt_blinding == NULL) rsa->mt_blinding = RSA_setup_blinding(rsa, ctx); } ret = rsa->mt_blinding; } err: if (got_write_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RSA); else CRYPTO_r_unlock(CRYPTO_LOCK_RSA); return ret; } static int rsa_blinding_convert(BN_BLINDING *b, BIGNUM *f, BIGNUM *unblind, BN_CTX *ctx) { if (unblind == NULL) /* * Local blinding: store the unblinding factor * in BN_BLINDING. */ return BN_BLINDING_convert_ex(f, NULL, b, ctx); else { /* * Shared blinding: store the unblinding factor * outside BN_BLINDING. */ int ret; CRYPTO_w_lock(CRYPTO_LOCK_RSA_BLINDING); ret = BN_BLINDING_convert_ex(f, unblind, b, ctx); CRYPTO_w_unlock(CRYPTO_LOCK_RSA_BLINDING); return ret; } } static int rsa_blinding_invert(BN_BLINDING *b, BIGNUM *f, BIGNUM *unblind, BN_CTX *ctx) { /* * For local blinding, unblind is set to NULL, and BN_BLINDING_invert_ex * will use the unblinding factor stored in BN_BLINDING. * If BN_BLINDING is shared between threads, unblind must be non-null: * BN_BLINDING_invert_ex will then use the local unblinding factor, * and will only read the modulus from BN_BLINDING. * In both cases it's safe to access the blinding without a lock. */ return BN_BLINDING_invert_ex(f, unblind, b, ctx); } /* signing */ static int RSA_eay_private_encrypt(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, int padding) { BIGNUM *f, *ret, *res; int i, j, k, 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 = malloc(num); if (f == NULL || ret == NULL || buf == NULL) { RSAerror(ERR_R_MALLOC_FAILURE); goto err; } switch (padding) { case RSA_PKCS1_PADDING: i = RSA_padding_add_PKCS1_type_1(buf, num, from, flen); break; case RSA_X931_PADDING: i = RSA_padding_add_X931(buf, num, from, flen); break; case RSA_NO_PADDING: i = RSA_padding_add_none(buf, num, from, flen); break; default: RSAerror(RSA_R_UNKNOWN_PADDING_TYPE); goto err; } if (i <= 0) goto err; if (BN_bin2bn(buf, num, f) == NULL) goto err; if (BN_ucmp(f, rsa->n) >= 0) { /* usually the padding functions would catch this */ RSAerror(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) { RSAerror(ERR_R_INTERNAL_ERROR); goto err; } } if (blinding != NULL) { if (!local_blinding && ((unblind = BN_CTX_get(ctx)) == NULL)) { RSAerror(ERR_R_MALLOC_FAILURE); goto err; } if (!rsa_blinding_convert(blinding, f, unblind, ctx)) goto err; } 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 d; BN_init(&d); BN_with_flags(&d, rsa->d, BN_FLG_CONSTTIME); 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; if (padding == RSA_X931_PADDING) { if (!BN_sub(f, rsa->n, ret)) goto err; if (BN_cmp(ret, f) > 0) res = f; else res = ret; } else res = ret; /* put in leading 0 bytes if the number is less than the * length of the modulus */ j = BN_num_bytes(res); i = BN_bn2bin(res, &(to[num - j])); for (k = 0; k < num - i; k++) to[k] = 0; r = num; err: if (ctx != NULL) { BN_CTX_end(ctx); BN_CTX_free(ctx); } freezero(buf, num); return r; } 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 *p; 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 = malloc(num); if (!f || !ret || !buf) { RSAerror(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) { RSAerror(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) { RSAerror(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) { RSAerror(ERR_R_INTERNAL_ERROR); goto err; } } if (blinding != NULL) { if (!local_blinding && ((unblind = BN_CTX_get(ctx)) == NULL)) { RSAerror(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 d; BN_init(&d); BN_with_flags(&d, rsa->d, BN_FLG_CONSTTIME); 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; p = buf; j = BN_bn2bin(ret, p); /* j is only used with no-padding mode */ 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_NO_PADDING: r = RSA_padding_check_none(to, num, buf, j, num); break; default: RSAerror(RSA_R_UNKNOWN_PADDING_TYPE); goto err; } if (r < 0) RSAerror(RSA_R_PADDING_CHECK_FAILED); err: if (ctx != NULL) { BN_CTX_end(ctx); BN_CTX_free(ctx); } freezero(buf, num); 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 *p; unsigned char *buf = NULL; BN_CTX *ctx = NULL; if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) { RSAerror(RSA_R_MODULUS_TOO_LARGE); return -1; } if (BN_ucmp(rsa->n, rsa->e) <= 0) { RSAerror(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) { RSAerror(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 = malloc(num); if (!f || !ret || !buf) { RSAerror(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) { RSAerror(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) { RSAerror(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; p = buf; i = BN_bn2bin(ret, p); 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: r = RSA_padding_check_none(to, num, buf, i, num); break; default: RSAerror(RSA_R_UNKNOWN_PADDING_TYPE); goto err; } if (r < 0) RSAerror(RSA_R_PADDING_CHECK_FAILED); err: if (ctx != NULL) { BN_CTX_end(ctx); BN_CTX_free(ctx); } freezero(buf, num); return r; } static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx) { BIGNUM *r1, *m1, *vrfy; BIGNUM dmp1, dmq1, c, pr1; int ret = 0; BN_CTX_start(ctx); r1 = BN_CTX_get(ctx); m1 = BN_CTX_get(ctx); vrfy = BN_CTX_get(ctx); if (r1 == NULL || m1 == NULL || vrfy == NULL) { RSAerror(ERR_R_MALLOC_FAILURE); goto err; } { BIGNUM p, q; /* * Make sure BN_mod_inverse in Montgomery initialization uses the * BN_FLG_CONSTTIME flag */ BN_init(&p); BN_init(&q); BN_with_flags(&p, rsa->p, BN_FLG_CONSTTIME); BN_with_flags(&q, rsa->q, BN_FLG_CONSTTIME); if (rsa->flags & RSA_FLAG_CACHE_PRIVATE) { if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_p, CRYPTO_LOCK_RSA, &p, ctx) || !BN_MONT_CTX_set_locked(&rsa->_method_mod_q, CRYPTO_LOCK_RSA, &q, ctx)) { 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; /* compute I mod q */ BN_init(&c); BN_with_flags(&c, I, BN_FLG_CONSTTIME); if (!BN_mod_ct(r1, &c, rsa->q, ctx)) goto err; /* compute r1^dmq1 mod q */ BN_init(&dmq1); BN_with_flags(&dmq1, rsa->dmq1, BN_FLG_CONSTTIME); if (!rsa->meth->bn_mod_exp(m1, r1, &dmq1, rsa->q, ctx, rsa->_method_mod_q)) goto err; /* compute I mod p */ BN_init(&c); BN_with_flags(&c, I, BN_FLG_CONSTTIME); if (!BN_mod_ct(r1, &c, rsa->p, ctx)) goto err; /* compute r1^dmp1 mod p */ BN_init(&dmp1); BN_with_flags(&dmp1, rsa->dmp1, BN_FLG_CONSTTIME); 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 */ BN_init(&pr1); BN_with_flags(&pr1, r1, BN_FLG_CONSTTIME); if (!BN_mod_ct(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; if (rsa->e && rsa->n) { 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_mod_ct(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_init(&d); 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)) { goto err; } } } 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) { BN_MONT_CTX_free(rsa->_method_mod_n); BN_MONT_CTX_free(rsa->_method_mod_p); BN_MONT_CTX_free(rsa->_method_mod_q); return 1; }