|
- /* 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.] */
-
- #include <openssl/rsa.h>
-
- #include <assert.h>
- #include <string.h>
-
- #include <openssl/bn.h>
- #include <openssl/err.h>
- #include <openssl/mem.h>
- #include <openssl/thread.h>
-
- #include "internal.h"
- #include "../bn/internal.h"
- #include "../internal.h"
-
-
- static int check_modulus_and_exponent_sizes(const RSA *rsa) {
- unsigned rsa_bits = BN_num_bits(rsa->n);
-
- if (rsa_bits > 16 * 1024) {
- OPENSSL_PUT_ERROR(RSA, RSA_R_MODULUS_TOO_LARGE);
- return 0;
- }
-
- /* Mitigate DoS attacks by limiting the exponent size. 33 bits was chosen as
- * the limit based on the recommendations in [1] and [2]. Windows CryptoAPI
- * doesn't support values larger than 32 bits [3], so it is unlikely that
- * exponents larger than 32 bits are being used for anything Windows commonly
- * does.
- *
- * [1] https://www.imperialviolet.org/2012/03/16/rsae.html
- * [2] https://www.imperialviolet.org/2012/03/17/rsados.html
- * [3] https://msdn.microsoft.com/en-us/library/aa387685(VS.85).aspx */
- static const unsigned kMaxExponentBits = 33;
-
- if (BN_num_bits(rsa->e) > kMaxExponentBits) {
- OPENSSL_PUT_ERROR(RSA, RSA_R_BAD_E_VALUE);
- return 0;
- }
-
- /* Verify |n > e|. Comparing |rsa_bits| to |kMaxExponentBits| is a small
- * shortcut to comparing |n| and |e| directly. In reality, |kMaxExponentBits|
- * is much smaller than the minimum RSA key size that any application should
- * accept. */
- if (rsa_bits <= kMaxExponentBits) {
- OPENSSL_PUT_ERROR(RSA, RSA_R_KEY_SIZE_TOO_SMALL);
- return 0;
- }
- assert(BN_ucmp(rsa->n, rsa->e) > 0);
-
- return 1;
- }
-
- size_t rsa_default_size(const RSA *rsa) {
- return BN_num_bytes(rsa->n);
- }
-
- int rsa_default_encrypt(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out,
- const uint8_t *in, size_t in_len, int padding) {
- const unsigned rsa_size = RSA_size(rsa);
- BIGNUM *f, *result;
- uint8_t *buf = NULL;
- BN_CTX *ctx = NULL;
- int i, ret = 0;
-
- if (max_out < rsa_size) {
- OPENSSL_PUT_ERROR(RSA, RSA_R_OUTPUT_BUFFER_TOO_SMALL);
- return 0;
- }
-
- if (!check_modulus_and_exponent_sizes(rsa)) {
- return 0;
- }
-
- ctx = BN_CTX_new();
- if (ctx == NULL) {
- goto err;
- }
-
- BN_CTX_start(ctx);
- f = BN_CTX_get(ctx);
- result = BN_CTX_get(ctx);
- buf = OPENSSL_malloc(rsa_size);
- if (!f || !result || !buf) {
- OPENSSL_PUT_ERROR(RSA, ERR_R_MALLOC_FAILURE);
- goto err;
- }
-
- switch (padding) {
- case RSA_PKCS1_PADDING:
- i = RSA_padding_add_PKCS1_type_2(buf, rsa_size, in, in_len);
- break;
- case RSA_PKCS1_OAEP_PADDING:
- /* Use the default parameters: SHA-1 for both hashes and no label. */
- i = RSA_padding_add_PKCS1_OAEP_mgf1(buf, rsa_size, in, in_len,
- NULL, 0, NULL, NULL);
- break;
- case RSA_NO_PADDING:
- i = RSA_padding_add_none(buf, rsa_size, in, in_len);
- break;
- default:
- OPENSSL_PUT_ERROR(RSA, RSA_R_UNKNOWN_PADDING_TYPE);
- goto err;
- }
-
- if (i <= 0) {
- goto err;
- }
-
- if (BN_bin2bn(buf, rsa_size, f) == NULL) {
- goto err;
- }
-
- if (BN_ucmp(f, rsa->n) >= 0) {
- /* usually the padding functions would catch this */
- OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
- goto err;
- }
-
- if (!BN_MONT_CTX_set_locked(&rsa->mont_n, &rsa->lock, rsa->n, ctx) ||
- !BN_mod_exp_mont(result, f, rsa->e, rsa->n, ctx, rsa->mont_n)) {
- goto err;
- }
-
- /* put in leading 0 bytes if the number is less than the length of the
- * modulus */
- if (!BN_bn2bin_padded(out, rsa_size, result)) {
- OPENSSL_PUT_ERROR(RSA, ERR_R_INTERNAL_ERROR);
- goto err;
- }
-
- *out_len = rsa_size;
- ret = 1;
-
- err:
- if (ctx != NULL) {
- BN_CTX_end(ctx);
- BN_CTX_free(ctx);
- }
- if (buf != NULL) {
- OPENSSL_cleanse(buf, rsa_size);
- OPENSSL_free(buf);
- }
-
- return ret;
- }
-
- /* MAX_BLINDINGS_PER_RSA defines the maximum number of cached BN_BLINDINGs per
- * RSA*. Then this limit is exceeded, BN_BLINDING objects will be created and
- * destroyed as needed. */
- #define MAX_BLINDINGS_PER_RSA 1024
-
- /* rsa_blinding_get returns a BN_BLINDING to use with |rsa|. It does this by
- * allocating one of the cached BN_BLINDING objects in |rsa->blindings|. If
- * none are free, the cache will be extended by a extra element and the new
- * BN_BLINDING is returned.
- *
- * On success, the index of the assigned BN_BLINDING is written to
- * |*index_used| and must be passed to |rsa_blinding_release| when finished. */
- static BN_BLINDING *rsa_blinding_get(RSA *rsa, unsigned *index_used,
- BN_CTX *ctx) {
- assert(ctx != NULL);
- assert(rsa->mont_n != NULL);
-
- BN_BLINDING *ret = NULL;
- BN_BLINDING **new_blindings;
- uint8_t *new_blindings_inuse;
- char overflow = 0;
-
- CRYPTO_MUTEX_lock_write(&rsa->lock);
-
- unsigned i;
- for (i = 0; i < rsa->num_blindings; i++) {
- if (rsa->blindings_inuse[i] == 0) {
- rsa->blindings_inuse[i] = 1;
- ret = rsa->blindings[i];
- *index_used = i;
- break;
- }
- }
-
- if (ret != NULL) {
- CRYPTO_MUTEX_unlock_write(&rsa->lock);
- return ret;
- }
-
- overflow = rsa->num_blindings >= MAX_BLINDINGS_PER_RSA;
-
- /* We didn't find a free BN_BLINDING to use so increase the length of
- * the arrays by one and use the newly created element. */
-
- CRYPTO_MUTEX_unlock_write(&rsa->lock);
- ret = BN_BLINDING_new();
- if (ret == NULL) {
- return NULL;
- }
-
- if (overflow) {
- /* We cannot add any more cached BN_BLINDINGs so we use |ret|
- * and mark it for destruction in |rsa_blinding_release|. */
- *index_used = MAX_BLINDINGS_PER_RSA;
- return ret;
- }
-
- CRYPTO_MUTEX_lock_write(&rsa->lock);
-
- new_blindings =
- OPENSSL_malloc(sizeof(BN_BLINDING *) * (rsa->num_blindings + 1));
- if (new_blindings == NULL) {
- goto err1;
- }
- OPENSSL_memcpy(new_blindings, rsa->blindings,
- sizeof(BN_BLINDING *) * rsa->num_blindings);
- new_blindings[rsa->num_blindings] = ret;
-
- new_blindings_inuse = OPENSSL_malloc(rsa->num_blindings + 1);
- if (new_blindings_inuse == NULL) {
- goto err2;
- }
- OPENSSL_memcpy(new_blindings_inuse, rsa->blindings_inuse, rsa->num_blindings);
- new_blindings_inuse[rsa->num_blindings] = 1;
- *index_used = rsa->num_blindings;
-
- OPENSSL_free(rsa->blindings);
- rsa->blindings = new_blindings;
- OPENSSL_free(rsa->blindings_inuse);
- rsa->blindings_inuse = new_blindings_inuse;
- rsa->num_blindings++;
-
- CRYPTO_MUTEX_unlock_write(&rsa->lock);
- return ret;
-
- err2:
- OPENSSL_free(new_blindings);
-
- err1:
- CRYPTO_MUTEX_unlock_write(&rsa->lock);
- BN_BLINDING_free(ret);
- return NULL;
- }
-
- /* rsa_blinding_release marks the cached BN_BLINDING at the given index as free
- * for other threads to use. */
- static void rsa_blinding_release(RSA *rsa, BN_BLINDING *blinding,
- unsigned blinding_index) {
- if (blinding_index == MAX_BLINDINGS_PER_RSA) {
- /* This blinding wasn't cached. */
- BN_BLINDING_free(blinding);
- return;
- }
-
- CRYPTO_MUTEX_lock_write(&rsa->lock);
- rsa->blindings_inuse[blinding_index] = 0;
- CRYPTO_MUTEX_unlock_write(&rsa->lock);
- }
-
- /* signing */
- int rsa_default_sign_raw(RSA *rsa, size_t *out_len, uint8_t *out,
- size_t max_out, const uint8_t *in, size_t in_len,
- int padding) {
- const unsigned rsa_size = RSA_size(rsa);
- uint8_t *buf = NULL;
- int i, ret = 0;
-
- if (max_out < rsa_size) {
- OPENSSL_PUT_ERROR(RSA, RSA_R_OUTPUT_BUFFER_TOO_SMALL);
- return 0;
- }
-
- buf = OPENSSL_malloc(rsa_size);
- if (buf == NULL) {
- OPENSSL_PUT_ERROR(RSA, ERR_R_MALLOC_FAILURE);
- goto err;
- }
-
- switch (padding) {
- case RSA_PKCS1_PADDING:
- i = RSA_padding_add_PKCS1_type_1(buf, rsa_size, in, in_len);
- break;
- case RSA_NO_PADDING:
- i = RSA_padding_add_none(buf, rsa_size, in, in_len);
- break;
- default:
- OPENSSL_PUT_ERROR(RSA, RSA_R_UNKNOWN_PADDING_TYPE);
- goto err;
- }
-
- if (i <= 0) {
- goto err;
- }
-
- if (!RSA_private_transform(rsa, out, buf, rsa_size)) {
- goto err;
- }
-
- *out_len = rsa_size;
- ret = 1;
-
- err:
- if (buf != NULL) {
- OPENSSL_cleanse(buf, rsa_size);
- OPENSSL_free(buf);
- }
-
- return ret;
- }
-
- int rsa_default_decrypt(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out,
- const uint8_t *in, size_t in_len, int padding) {
- const unsigned rsa_size = RSA_size(rsa);
- int r = -1;
- uint8_t *buf = NULL;
- int ret = 0;
-
- if (max_out < rsa_size) {
- OPENSSL_PUT_ERROR(RSA, RSA_R_OUTPUT_BUFFER_TOO_SMALL);
- return 0;
- }
-
- if (padding == RSA_NO_PADDING) {
- buf = out;
- } else {
- /* Allocate a temporary buffer to hold the padded plaintext. */
- buf = OPENSSL_malloc(rsa_size);
- if (buf == NULL) {
- OPENSSL_PUT_ERROR(RSA, ERR_R_MALLOC_FAILURE);
- goto err;
- }
- }
-
- if (in_len != rsa_size) {
- OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_LEN_NOT_EQUAL_TO_MOD_LEN);
- goto err;
- }
-
- if (!RSA_private_transform(rsa, buf, in, rsa_size)) {
- goto err;
- }
-
- switch (padding) {
- case RSA_PKCS1_PADDING:
- r = RSA_padding_check_PKCS1_type_2(out, rsa_size, buf, rsa_size);
- break;
- case RSA_PKCS1_OAEP_PADDING:
- /* Use the default parameters: SHA-1 for both hashes and no label. */
- r = RSA_padding_check_PKCS1_OAEP_mgf1(out, rsa_size, buf, rsa_size,
- NULL, 0, NULL, NULL);
- break;
- case RSA_NO_PADDING:
- r = rsa_size;
- break;
- default:
- OPENSSL_PUT_ERROR(RSA, RSA_R_UNKNOWN_PADDING_TYPE);
- goto err;
- }
-
- if (r < 0) {
- OPENSSL_PUT_ERROR(RSA, RSA_R_PADDING_CHECK_FAILED);
- } else {
- *out_len = r;
- ret = 1;
- }
-
- err:
- if (padding != RSA_NO_PADDING && buf != NULL) {
- OPENSSL_cleanse(buf, rsa_size);
- OPENSSL_free(buf);
- }
-
- return ret;
- }
-
- static int mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx);
-
- int RSA_verify_raw(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out,
- const uint8_t *in, size_t in_len, int padding) {
- if (rsa->n == NULL || rsa->e == NULL) {
- OPENSSL_PUT_ERROR(RSA, RSA_R_VALUE_MISSING);
- return 0;
- }
-
- const unsigned rsa_size = RSA_size(rsa);
- BIGNUM *f, *result;
- int r = -1;
-
- if (max_out < rsa_size) {
- OPENSSL_PUT_ERROR(RSA, RSA_R_OUTPUT_BUFFER_TOO_SMALL);
- return 0;
- }
-
- if (in_len != rsa_size) {
- OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_LEN_NOT_EQUAL_TO_MOD_LEN);
- return 0;
- }
-
- if (!check_modulus_and_exponent_sizes(rsa)) {
- return 0;
- }
-
- BN_CTX *ctx = BN_CTX_new();
- if (ctx == NULL) {
- return 0;
- }
-
- int ret = 0;
- uint8_t *buf = NULL;
-
- BN_CTX_start(ctx);
- f = BN_CTX_get(ctx);
- result = BN_CTX_get(ctx);
- if (f == NULL || result == NULL) {
- OPENSSL_PUT_ERROR(RSA, ERR_R_MALLOC_FAILURE);
- goto err;
- }
-
- if (padding == RSA_NO_PADDING) {
- buf = out;
- } else {
- /* Allocate a temporary buffer to hold the padded plaintext. */
- buf = OPENSSL_malloc(rsa_size);
- if (buf == NULL) {
- OPENSSL_PUT_ERROR(RSA, ERR_R_MALLOC_FAILURE);
- goto err;
- }
- }
-
- if (BN_bin2bn(in, in_len, f) == NULL) {
- goto err;
- }
-
- if (BN_ucmp(f, rsa->n) >= 0) {
- OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
- goto err;
- }
-
- if (!BN_MONT_CTX_set_locked(&rsa->mont_n, &rsa->lock, rsa->n, ctx) ||
- !BN_mod_exp_mont(result, f, rsa->e, rsa->n, ctx, rsa->mont_n)) {
- goto err;
- }
-
- if (!BN_bn2bin_padded(buf, rsa_size, result)) {
- OPENSSL_PUT_ERROR(RSA, ERR_R_INTERNAL_ERROR);
- goto err;
- }
-
- switch (padding) {
- case RSA_PKCS1_PADDING:
- r = RSA_padding_check_PKCS1_type_1(out, rsa_size, buf, rsa_size);
- break;
- case RSA_NO_PADDING:
- r = rsa_size;
- break;
- default:
- OPENSSL_PUT_ERROR(RSA, RSA_R_UNKNOWN_PADDING_TYPE);
- goto err;
- }
-
- if (r < 0) {
- OPENSSL_PUT_ERROR(RSA, RSA_R_PADDING_CHECK_FAILED);
- } else {
- *out_len = r;
- ret = 1;
- }
-
- err:
- BN_CTX_end(ctx);
- BN_CTX_free(ctx);
- if (buf != out) {
- OPENSSL_free(buf);
- }
- return ret;
- }
-
- int rsa_default_private_transform(RSA *rsa, uint8_t *out, const uint8_t *in,
- size_t len) {
- BIGNUM *f, *result;
- BN_CTX *ctx = NULL;
- unsigned blinding_index = 0;
- BN_BLINDING *blinding = NULL;
- int ret = 0;
-
- ctx = BN_CTX_new();
- if (ctx == NULL) {
- goto err;
- }
- BN_CTX_start(ctx);
- f = BN_CTX_get(ctx);
- result = BN_CTX_get(ctx);
-
- if (f == NULL || result == NULL) {
- OPENSSL_PUT_ERROR(RSA, ERR_R_MALLOC_FAILURE);
- goto err;
- }
-
- if (BN_bin2bn(in, len, f) == NULL) {
- goto err;
- }
-
- if (BN_ucmp(f, rsa->n) >= 0) {
- /* Usually the padding functions would catch this. */
- OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
- goto err;
- }
-
- if (!BN_MONT_CTX_set_locked(&rsa->mont_n, &rsa->lock, rsa->n, ctx)) {
- OPENSSL_PUT_ERROR(RSA, ERR_R_INTERNAL_ERROR);
- goto err;
- }
-
- /* We cannot do blinding or verification without |e|, and continuing without
- * those countermeasures is dangerous. However, the Java/Android RSA API
- * requires support for keys where only |d| and |n| (and not |e|) are known.
- * The callers that require that bad behavior set |RSA_FLAG_NO_BLINDING|. */
- int disable_security = (rsa->flags & RSA_FLAG_NO_BLINDING) && rsa->e == NULL;
-
- if (!disable_security) {
- /* Keys without public exponents must have blinding explicitly disabled to
- * be used. */
- if (rsa->e == NULL) {
- OPENSSL_PUT_ERROR(RSA, RSA_R_NO_PUBLIC_EXPONENT);
- goto err;
- }
-
- blinding = rsa_blinding_get(rsa, &blinding_index, ctx);
- if (blinding == NULL) {
- OPENSSL_PUT_ERROR(RSA, ERR_R_INTERNAL_ERROR);
- goto err;
- }
- if (!BN_BLINDING_convert(f, blinding, rsa->e, rsa->mont_n, ctx)) {
- goto err;
- }
- }
-
- if (rsa->p != NULL && rsa->q != NULL && rsa->e != NULL && rsa->dmp1 != NULL &&
- rsa->dmq1 != NULL && rsa->iqmp != NULL) {
- if (!mod_exp(result, f, rsa, ctx)) {
- goto err;
- }
- } else if (!BN_mod_exp_mont_consttime(result, f, rsa->d, rsa->n, ctx,
- rsa->mont_n)) {
- goto err;
- }
-
- /* Verify the result to protect against fault attacks as described in the
- * 1997 paper "On the Importance of Checking Cryptographic Protocols for
- * Faults" by Dan Boneh, Richard A. DeMillo, and Richard J. Lipton. Some
- * implementations do this only when the CRT is used, but we do it in all
- * cases. Section 6 of the aforementioned paper describes an attack that
- * works when the CRT isn't used. That attack is much less likely to succeed
- * than the CRT attack, but there have likely been improvements since 1997.
- *
- * This check is cheap assuming |e| is small; it almost always is. */
- if (!disable_security) {
- BIGNUM *vrfy = BN_CTX_get(ctx);
- if (vrfy == NULL ||
- !BN_mod_exp_mont(vrfy, result, rsa->e, rsa->n, ctx, rsa->mont_n) ||
- !BN_equal_consttime(vrfy, f)) {
- OPENSSL_PUT_ERROR(RSA, ERR_R_INTERNAL_ERROR);
- goto err;
- }
-
- if (!BN_BLINDING_invert(result, blinding, rsa->mont_n, ctx)) {
- goto err;
- }
- }
-
- if (!BN_bn2bin_padded(out, len, result)) {
- OPENSSL_PUT_ERROR(RSA, ERR_R_INTERNAL_ERROR);
- goto err;
- }
-
- ret = 1;
-
- err:
- if (ctx != NULL) {
- BN_CTX_end(ctx);
- BN_CTX_free(ctx);
- }
- if (blinding != NULL) {
- rsa_blinding_release(rsa, blinding, blinding_index);
- }
-
- return ret;
- }
-
- static int mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx) {
- assert(ctx != NULL);
-
- assert(rsa->n != NULL);
- assert(rsa->e != NULL);
- assert(rsa->d != NULL);
- assert(rsa->p != NULL);
- assert(rsa->q != NULL);
- assert(rsa->dmp1 != NULL);
- assert(rsa->dmq1 != NULL);
- assert(rsa->iqmp != NULL);
-
- BIGNUM *r1, *m1, *vrfy;
- int ret = 0;
- size_t i, num_additional_primes = 0;
-
- if (rsa->additional_primes != NULL) {
- num_additional_primes = sk_RSA_additional_prime_num(rsa->additional_primes);
- }
-
- 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) {
- goto err;
- }
-
- if (!BN_MONT_CTX_set_locked(&rsa->mont_p, &rsa->lock, rsa->p, ctx) ||
- !BN_MONT_CTX_set_locked(&rsa->mont_q, &rsa->lock, rsa->q, ctx)) {
- goto err;
- }
-
- if (!BN_MONT_CTX_set_locked(&rsa->mont_n, &rsa->lock, rsa->n, ctx)) {
- goto err;
- }
-
- /* compute I mod q */
- if (!BN_mod(r1, I, rsa->q, ctx)) {
- goto err;
- }
-
- /* compute r1^dmq1 mod q */
- if (!BN_mod_exp_mont_consttime(m1, r1, rsa->dmq1, rsa->q, ctx, rsa->mont_q)) {
- goto err;
- }
-
- /* compute I mod p */
- if (!BN_mod(r1, I, rsa->p, ctx)) {
- goto err;
- }
-
- /* compute r1^dmp1 mod p */
- if (!BN_mod_exp_mont_consttime(r0, r1, rsa->dmp1, rsa->p, ctx, rsa->mont_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;
- }
-
- if (!BN_mod(r0, r1, 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;
- }
-
- for (i = 0; i < num_additional_primes; i++) {
- /* multi-prime RSA. */
- RSA_additional_prime *ap =
- sk_RSA_additional_prime_value(rsa->additional_primes, i);
-
- /* c will already point to a BIGNUM with the correct flags. */
- if (!BN_mod(r1, I, ap->prime, ctx)) {
- goto err;
- }
-
- if (!BN_MONT_CTX_set_locked(&ap->mont, &rsa->lock, ap->prime, ctx) ||
- !BN_mod_exp_mont_consttime(m1, r1, ap->exp, ap->prime, ctx, ap->mont)) {
- goto err;
- }
-
- if (!BN_sub(m1, m1, r0) ||
- !BN_mul(m1, m1, ap->coeff, ctx) ||
- !BN_mod(m1, m1, ap->prime, ctx) ||
- (BN_is_negative(m1) && !BN_add(m1, m1, ap->prime)) ||
- !BN_mul(m1, m1, ap->r, ctx) ||
- !BN_add(r0, r0, m1)) {
- goto err;
- }
- }
-
- ret = 1;
-
- err:
- BN_CTX_end(ctx);
- return ret;
- }
-
- int rsa_default_multi_prime_keygen(RSA *rsa, int bits, int num_primes,
- BIGNUM *e_value, BN_GENCB *cb) {
- BIGNUM *r0 = NULL, *r1 = NULL, *r2 = NULL, *r3 = NULL, *tmp;
- int prime_bits, ok = -1, n = 0, i, j;
- BN_CTX *ctx = NULL;
- STACK_OF(RSA_additional_prime) *additional_primes = NULL;
-
- if (num_primes < 2) {
- ok = 0; /* we set our own err */
- OPENSSL_PUT_ERROR(RSA, RSA_R_MUST_HAVE_AT_LEAST_TWO_PRIMES);
- goto err;
- }
-
- ctx = BN_CTX_new();
- if (ctx == NULL) {
- goto err;
- }
- BN_CTX_start(ctx);
- r0 = BN_CTX_get(ctx);
- r1 = BN_CTX_get(ctx);
- r2 = BN_CTX_get(ctx);
- r3 = BN_CTX_get(ctx);
- if (r0 == NULL || r1 == NULL || r2 == NULL || r3 == NULL) {
- goto err;
- }
-
- if (num_primes > 2) {
- additional_primes = sk_RSA_additional_prime_new_null();
- if (additional_primes == NULL) {
- goto err;
- }
- }
-
- for (i = 2; i < num_primes; i++) {
- RSA_additional_prime *ap = OPENSSL_malloc(sizeof(RSA_additional_prime));
- if (ap == NULL) {
- goto err;
- }
- OPENSSL_memset(ap, 0, sizeof(RSA_additional_prime));
- ap->prime = BN_new();
- ap->exp = BN_new();
- ap->coeff = BN_new();
- ap->r = BN_new();
- if (ap->prime == NULL ||
- ap->exp == NULL ||
- ap->coeff == NULL ||
- ap->r == NULL ||
- !sk_RSA_additional_prime_push(additional_primes, ap)) {
- RSA_additional_prime_free(ap);
- goto err;
- }
- }
-
- /* We need the RSA components non-NULL */
- if (!rsa->n && ((rsa->n = BN_new()) == NULL)) {
- goto err;
- }
- if (!rsa->d && ((rsa->d = BN_new()) == NULL)) {
- goto err;
- }
- if (!rsa->e && ((rsa->e = BN_new()) == NULL)) {
- goto err;
- }
- if (!rsa->p && ((rsa->p = BN_new()) == NULL)) {
- goto err;
- }
- if (!rsa->q && ((rsa->q = BN_new()) == NULL)) {
- goto err;
- }
- if (!rsa->dmp1 && ((rsa->dmp1 = BN_new()) == NULL)) {
- goto err;
- }
- if (!rsa->dmq1 && ((rsa->dmq1 = BN_new()) == NULL)) {
- goto err;
- }
- if (!rsa->iqmp && ((rsa->iqmp = BN_new()) == NULL)) {
- goto err;
- }
-
- if (!BN_copy(rsa->e, e_value)) {
- goto err;
- }
-
- /* generate p and q */
- prime_bits = (bits + (num_primes - 1)) / num_primes;
- for (;;) {
- if (!BN_generate_prime_ex(rsa->p, prime_bits, 0, NULL, NULL, cb) ||
- !BN_sub(r2, rsa->p, BN_value_one()) ||
- !BN_gcd(r1, r2, rsa->e, ctx)) {
- goto err;
- }
- if (BN_is_one(r1)) {
- break;
- }
- if (!BN_GENCB_call(cb, 2, n++)) {
- goto err;
- }
- }
- if (!BN_GENCB_call(cb, 3, 0)) {
- goto err;
- }
- prime_bits = ((bits - prime_bits) + (num_primes - 2)) / (num_primes - 1);
- for (;;) {
- /* When generating ridiculously small keys, we can get stuck
- * continually regenerating the same prime values. Check for
- * this and bail if it happens 3 times. */
- unsigned int degenerate = 0;
- do {
- if (!BN_generate_prime_ex(rsa->q, prime_bits, 0, NULL, NULL, cb)) {
- goto err;
- }
- } while ((BN_cmp(rsa->p, rsa->q) == 0) && (++degenerate < 3));
- if (degenerate == 3) {
- ok = 0; /* we set our own err */
- OPENSSL_PUT_ERROR(RSA, RSA_R_KEY_SIZE_TOO_SMALL);
- goto err;
- }
- if (!BN_sub(r2, rsa->q, BN_value_one()) ||
- !BN_gcd(r1, r2, rsa->e, ctx)) {
- goto err;
- }
- if (BN_is_one(r1)) {
- break;
- }
- if (!BN_GENCB_call(cb, 2, n++)) {
- goto err;
- }
- }
-
- if (!BN_GENCB_call(cb, 3, 1) ||
- !BN_mul(rsa->n, rsa->p, rsa->q, ctx)) {
- goto err;
- }
-
- for (i = 2; i < num_primes; i++) {
- RSA_additional_prime *ap =
- sk_RSA_additional_prime_value(additional_primes, i - 2);
- prime_bits = ((bits - BN_num_bits(rsa->n)) + (num_primes - (i + 1))) /
- (num_primes - i);
-
- for (;;) {
- if (!BN_generate_prime_ex(ap->prime, prime_bits, 0, NULL, NULL, cb)) {
- goto err;
- }
- if (BN_cmp(rsa->p, ap->prime) == 0 ||
- BN_cmp(rsa->q, ap->prime) == 0) {
- continue;
- }
-
- for (j = 0; j < i - 2; j++) {
- if (BN_cmp(sk_RSA_additional_prime_value(additional_primes, j)->prime,
- ap->prime) == 0) {
- break;
- }
- }
- if (j != i - 2) {
- continue;
- }
-
- if (!BN_sub(r2, ap->prime, BN_value_one()) ||
- !BN_gcd(r1, r2, rsa->e, ctx)) {
- goto err;
- }
-
- if (!BN_is_one(r1)) {
- continue;
- }
- if (i != num_primes - 1) {
- break;
- }
-
- /* For the last prime we'll check that it makes n large enough. In the
- * two prime case this isn't a problem because we generate primes with
- * the top two bits set and so the product is always of the expected
- * size. In the multi prime case, this doesn't follow. */
- if (!BN_mul(r1, rsa->n, ap->prime, ctx)) {
- goto err;
- }
- if (BN_num_bits(r1) == (unsigned) bits) {
- break;
- }
-
- if (!BN_GENCB_call(cb, 2, n++)) {
- goto err;
- }
- }
-
- /* ap->r is is the product of all the primes prior to the current one
- * (including p and q). */
- if (!BN_copy(ap->r, rsa->n)) {
- goto err;
- }
- if (i == num_primes - 1) {
- /* In the case of the last prime, we calculated n as |r1| in the loop
- * above. */
- if (!BN_copy(rsa->n, r1)) {
- goto err;
- }
- } else if (!BN_mul(rsa->n, rsa->n, ap->prime, ctx)) {
- goto err;
- }
-
- if (!BN_GENCB_call(cb, 3, 1)) {
- goto err;
- }
- }
-
- if (BN_cmp(rsa->p, rsa->q) < 0) {
- tmp = rsa->p;
- rsa->p = rsa->q;
- rsa->q = tmp;
- }
-
- /* calculate d */
- if (!BN_sub(r1, rsa->p, BN_value_one())) {
- goto err; /* p-1 */
- }
- if (!BN_sub(r2, rsa->q, BN_value_one())) {
- goto err; /* q-1 */
- }
- if (!BN_mul(r0, r1, r2, ctx)) {
- goto err; /* (p-1)(q-1) */
- }
- for (i = 2; i < num_primes; i++) {
- RSA_additional_prime *ap =
- sk_RSA_additional_prime_value(additional_primes, i - 2);
- if (!BN_sub(r3, ap->prime, BN_value_one()) ||
- !BN_mul(r0, r0, r3, ctx)) {
- goto err;
- }
- }
- if (!BN_mod_inverse(rsa->d, rsa->e, r0, ctx)) {
- goto err; /* d */
- }
-
- /* calculate d mod (p-1) */
- if (!BN_mod(rsa->dmp1, rsa->d, r1, ctx)) {
- goto err;
- }
-
- /* calculate d mod (q-1) */
- if (!BN_mod(rsa->dmq1, rsa->d, r2, ctx)) {
- goto err;
- }
-
- /* Calculate inverse of q mod p. Note that although RSA key generation is far
- * from constant-time, |bn_mod_inverse_secret_prime| uses the same modular
- * exponentation logic as in RSA private key operations and, if the RSAZ-1024
- * code is enabled, will be optimized for common RSA prime sizes. */
- if (!BN_MONT_CTX_set_locked(&rsa->mont_p, &rsa->lock, rsa->p, ctx) ||
- !bn_mod_inverse_secret_prime(rsa->iqmp, rsa->q, rsa->p, ctx,
- rsa->mont_p)) {
- goto err;
- }
-
- for (i = 2; i < num_primes; i++) {
- RSA_additional_prime *ap =
- sk_RSA_additional_prime_value(additional_primes, i - 2);
- if (!BN_sub(ap->exp, ap->prime, BN_value_one()) ||
- !BN_mod(ap->exp, rsa->d, ap->exp, ctx) ||
- !BN_MONT_CTX_set_locked(&ap->mont, &rsa->lock, ap->prime, ctx) ||
- !bn_mod_inverse_secret_prime(ap->coeff, ap->r, ap->prime, ctx,
- ap->mont)) {
- goto err;
- }
- }
-
- rsa->additional_primes = additional_primes;
- additional_primes = NULL;
-
- /* The key generation process is complex and thus error-prone. It could be
- * disastrous to generate and then use a bad key so double-check that the key
- * makes sense. */
- ok = RSA_check_key(rsa);
- if (!ok) {
- OPENSSL_PUT_ERROR(RSA, RSA_R_INTERNAL_ERROR);
- }
-
- err:
- if (ok == -1) {
- OPENSSL_PUT_ERROR(RSA, ERR_LIB_BN);
- ok = 0;
- }
- if (ctx != NULL) {
- BN_CTX_end(ctx);
- BN_CTX_free(ctx);
- }
- sk_RSA_additional_prime_pop_free(additional_primes,
- RSA_additional_prime_free);
- return ok;
- }
-
- int rsa_default_keygen(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb) {
- return rsa_default_multi_prime_keygen(rsa, bits, 2 /* num primes */, e_value,
- cb);
- }
-
- /* All of the methods are NULL to make it easier for the compiler/linker to drop
- * unused functions. The wrapper functions will select the appropriate
- * |rsa_default_*| implementation. */
- const RSA_METHOD RSA_default_method = {
- {
- 0 /* references */,
- 1 /* is_static */,
- },
- NULL /* app_data */,
-
- NULL /* init */,
- NULL /* finish (defaults to rsa_default_finish) */,
-
- NULL /* size (defaults to rsa_default_size) */,
-
- NULL /* sign */,
- NULL /* verify */,
-
- NULL /* encrypt (defaults to rsa_default_encrypt) */,
- NULL /* sign_raw (defaults to rsa_default_sign_raw) */,
- NULL /* decrypt (defaults to rsa_default_decrypt) */,
- NULL /* verify_raw (defaults to rsa_default_verify_raw) */,
-
- NULL /* private_transform (defaults to rsa_default_private_transform) */,
-
- NULL /* mod_exp (ignored) */,
- NULL /* bn_mod_exp (ignored) */,
-
- RSA_FLAG_CACHE_PUBLIC | RSA_FLAG_CACHE_PRIVATE,
-
- NULL /* keygen (defaults to rsa_default_keygen) */,
- NULL /* multi_prime_keygen (defaults to rsa_default_multi_prime_keygen) */,
-
- NULL /* supports_digest */,
- };
|