/* 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 */,
};