diff options
Diffstat (limited to 'src/crypto/rsa/rsa_impl.c')
| -rw-r--r-- | src/crypto/rsa/rsa_impl.c | 960 |
1 files changed, 960 insertions, 0 deletions
diff --git a/src/crypto/rsa/rsa_impl.c b/src/crypto/rsa/rsa_impl.c new file mode 100644 index 0000000..d950d50 --- /dev/null +++ b/src/crypto/rsa/rsa_impl.c @@ -0,0 +1,960 @@ +/* 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 <string.h> + +#include <openssl/bn.h> +#include <openssl/err.h> +#include <openssl/mem.h> + +#include "internal.h" + + +#define OPENSSL_RSA_MAX_MODULUS_BITS 16384 +#define OPENSSL_RSA_SMALL_MODULUS_BITS 3072 +#define OPENSSL_RSA_MAX_PUBEXP_BITS \ + 64 /* exponent limit enforced for "large" modulus only */ + + +static int finish(RSA *rsa) { + if (rsa->_method_mod_n != NULL) { + BN_MONT_CTX_free(rsa->_method_mod_n); + } + if (rsa->_method_mod_p != NULL) { + BN_MONT_CTX_free(rsa->_method_mod_p); + } + if (rsa->_method_mod_q != NULL) { + BN_MONT_CTX_free(rsa->_method_mod_q); + } + + return 1; +} + +static size_t size(const RSA *rsa) { + return BN_num_bytes(rsa->n); +} + +static int 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 (rsa_size > OPENSSL_RSA_MAX_MODULUS_BITS) { + OPENSSL_PUT_ERROR(RSA, encrypt, RSA_R_MODULUS_TOO_LARGE); + return 0; + } + + if (max_out < rsa_size) { + OPENSSL_PUT_ERROR(RSA, encrypt, RSA_R_OUTPUT_BUFFER_TOO_SMALL); + return 0; + } + + if (BN_ucmp(rsa->n, rsa->e) <= 0) { + OPENSSL_PUT_ERROR(RSA, encrypt, RSA_R_BAD_E_VALUE); + return 0; + } + + /* for large moduli, enforce exponent limit */ + if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS && + BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) { + OPENSSL_PUT_ERROR(RSA, encrypt, RSA_R_BAD_E_VALUE); + 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, encrypt, 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, encrypt, 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, encrypt, 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(result, 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 */ + if (!BN_bn2bin_padded(out, rsa_size, result)) { + OPENSSL_PUT_ERROR(RSA, encrypt, 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) { + BN_BLINDING *ret = NULL; + BN_BLINDING **new_blindings; + uint8_t *new_blindings_inuse; + char overflow = 0; + + CRYPTO_w_lock(CRYPTO_LOCK_RSA_BLINDING); + if (rsa->num_blindings > 0) { + unsigned i, starting_index; + CRYPTO_THREADID threadid; + + /* We start searching the array at a value based on the + * threadid in order to try avoid bouncing the BN_BLINDING + * values around different threads. It's harmless if + * threadid.val is always set to zero. */ + CRYPTO_THREADID_current(&threadid); + starting_index = threadid.val % rsa->num_blindings; + + for (i = starting_index;;) { + if (rsa->blindings_inuse[i] == 0) { + rsa->blindings_inuse[i] = 1; + ret = rsa->blindings[i]; + *index_used = i; + break; + } + i++; + if (i == rsa->num_blindings) { + i = 0; + } + if (i == starting_index) { + break; + } + } + } + + if (ret != NULL) { + CRYPTO_w_unlock(CRYPTO_LOCK_RSA_BLINDING); + 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_w_unlock(CRYPTO_LOCK_RSA_BLINDING); + ret = rsa_setup_blinding(rsa, ctx); + 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_w_lock(CRYPTO_LOCK_RSA_BLINDING); + + new_blindings = + OPENSSL_malloc(sizeof(BN_BLINDING *) * (rsa->num_blindings + 1)); + if (new_blindings == NULL) { + goto err1; + } + 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; + } + memcpy(new_blindings_inuse, rsa->blindings_inuse, rsa->num_blindings); + new_blindings_inuse[rsa->num_blindings] = 1; + *index_used = rsa->num_blindings; + + if (rsa->blindings != NULL) { + OPENSSL_free(rsa->blindings); + } + rsa->blindings = new_blindings; + if (rsa->blindings_inuse != NULL) { + OPENSSL_free(rsa->blindings_inuse); + } + rsa->blindings_inuse = new_blindings_inuse; + rsa->num_blindings++; + + CRYPTO_w_unlock(CRYPTO_LOCK_RSA_BLINDING); + return ret; + +err2: + OPENSSL_free(new_blindings); + +err1: + CRYPTO_w_unlock(CRYPTO_LOCK_RSA_BLINDING); + 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_w_lock(CRYPTO_LOCK_RSA_BLINDING); + rsa->blindings_inuse[blinding_index] = 0; + CRYPTO_w_unlock(CRYPTO_LOCK_RSA_BLINDING); +} + +/* signing */ +static int 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, sign_raw, RSA_R_OUTPUT_BUFFER_TOO_SMALL); + return 0; + } + + buf = OPENSSL_malloc(rsa_size); + if (buf == NULL) { + OPENSSL_PUT_ERROR(RSA, sign_raw, 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, sign_raw, RSA_R_UNKNOWN_PADDING_TYPE); + goto err; + } + + if (i <= 0) { + goto err; + } + + if (!RSA_private_transform(rsa, out, buf, rsa_size)) { + OPENSSL_PUT_ERROR(RSA, sign_raw, ERR_R_INTERNAL_ERROR); + goto err; + } + + *out_len = rsa_size; + ret = 1; + +err: + if (buf != NULL) { + OPENSSL_cleanse(buf, rsa_size); + OPENSSL_free(buf); + } + + return ret; +} + +static int 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, decrypt, RSA_R_OUTPUT_BUFFER_TOO_SMALL); + return 0; + } + + buf = OPENSSL_malloc(rsa_size); + if (buf == NULL) { + OPENSSL_PUT_ERROR(RSA, decrypt, ERR_R_MALLOC_FAILURE); + goto err; + } + + if (in_len != rsa_size) { + OPENSSL_PUT_ERROR(RSA, decrypt, RSA_R_DATA_LEN_NOT_EQUAL_TO_MOD_LEN); + goto err; + } + + if (!RSA_private_transform(rsa, buf, in, rsa_size)) { + OPENSSL_PUT_ERROR(RSA, decrypt, ERR_R_INTERNAL_ERROR); + 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_padding_check_none(out, rsa_size, buf, rsa_size); + break; + default: + OPENSSL_PUT_ERROR(RSA, decrypt, RSA_R_UNKNOWN_PADDING_TYPE); + goto err; + } + + if (r < 0) { + OPENSSL_PUT_ERROR(RSA, decrypt, RSA_R_PADDING_CHECK_FAILED); + } else { + *out_len = r; + ret = 1; + } + +err: + if (buf != NULL) { + OPENSSL_cleanse(buf, rsa_size); + OPENSSL_free(buf); + } + + return ret; +} + +static int 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) { + const unsigned rsa_size = RSA_size(rsa); + BIGNUM *f, *result; + int ret = 0; + int r = -1; + uint8_t *buf = NULL; + BN_CTX *ctx = NULL; + + if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) { + OPENSSL_PUT_ERROR(RSA, verify_raw, RSA_R_MODULUS_TOO_LARGE); + return 0; + } + + if (BN_ucmp(rsa->n, rsa->e) <= 0) { + OPENSSL_PUT_ERROR(RSA, verify_raw, RSA_R_BAD_E_VALUE); + return 0; + } + + if (max_out < rsa_size) { + OPENSSL_PUT_ERROR(RSA, verify_raw, RSA_R_OUTPUT_BUFFER_TOO_SMALL); + return 0; + } + + /* for large moduli, enforce exponent limit */ + if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS && + BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) { + OPENSSL_PUT_ERROR(RSA, verify_raw, RSA_R_BAD_E_VALUE); + 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, verify_raw, ERR_R_MALLOC_FAILURE); + goto err; + } + + if (in_len != rsa_size) { + OPENSSL_PUT_ERROR(RSA, verify_raw, RSA_R_DATA_LEN_NOT_EQUAL_TO_MOD_LEN); + goto err; + } + + if (BN_bin2bn(in, in_len, f) == NULL) { + goto err; + } + + if (BN_ucmp(f, rsa->n) >= 0) { + OPENSSL_PUT_ERROR(RSA, verify_raw, 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(result, f, rsa->e, rsa->n, ctx, + rsa->_method_mod_n)) { + goto err; + } + + if (!BN_bn2bin_padded(buf, rsa_size, result)) { + OPENSSL_PUT_ERROR(RSA, verify_raw, 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_padding_check_none(out, rsa_size, buf, rsa_size); + break; + default: + OPENSSL_PUT_ERROR(RSA, verify_raw, RSA_R_UNKNOWN_PADDING_TYPE); + goto err; + } + + if (r < 0) { + OPENSSL_PUT_ERROR(RSA, verify_raw, RSA_R_PADDING_CHECK_FAILED); + } else { + *out_len = r; + 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; +} + +static int 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, private_transform, 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, private_transform, RSA_R_DATA_TOO_LARGE_FOR_MODULUS); + goto err; + } + + if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) { + blinding = rsa_blinding_get(rsa, &blinding_index, ctx); + if (blinding == NULL) { + OPENSSL_PUT_ERROR(RSA, private_transform, ERR_R_INTERNAL_ERROR); + goto err; + } + if (!BN_BLINDING_convert_ex(f, NULL, blinding, 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->mod_exp(result, f, rsa, ctx)) { + goto err; + } + } else { + BIGNUM local_d; + BIGNUM *d = NULL; + + BN_init(&local_d); + d = &local_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(result, f, d, rsa->n, ctx, rsa->_method_mod_n)) { + goto err; + } + } + + if (blinding) { + if (!BN_BLINDING_invert_ex(result, NULL, blinding, ctx)) { + goto err; + } + } + + if (!BN_bn2bin_padded(out, len, result)) { + OPENSSL_PUT_ERROR(RSA, private_transform, 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) { + BIGNUM *r1, *m1, *vrfy; + BIGNUM local_dmp1, local_dmq1, local_c, local_r1; + 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); + + { + BIGNUM local_p, local_q; + BIGNUM *p = NULL, *q = NULL; + + /* Make sure BN_mod_inverse in Montgomery intialization uses the + * BN_FLG_CONSTTIME flag (unless RSA_FLAG_NO_CONSTTIME is set) */ + BN_init(&local_p); + p = &local_p; + BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME); + + BN_init(&local_q); + q = &local_q; + BN_with_flags(q, rsa->q, BN_FLG_CONSTTIME); + + if (rsa->flags & RSA_FLAG_CACHE_PRIVATE) { + if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_p, CRYPTO_LOCK_RSA, p, ctx)) { + goto err; + } + if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_q, CRYPTO_LOCK_RSA, q, ctx)) { + goto err; + } + } + } + + 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 */ + c = &local_c; + BN_with_flags(c, I, BN_FLG_CONSTTIME); + if (!BN_mod(r1, c, rsa->q, ctx)) { + goto err; + } + + /* compute r1^dmq1 mod q */ + dmq1 = &local_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 */ + c = &local_c; + BN_with_flags(c, I, BN_FLG_CONSTTIME); + if (!BN_mod(r1, c, rsa->p, ctx)) { + goto err; + } + + /* compute r1^dmp1 mod p */ + dmp1 = &local_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 */ + pr1 = &local_r1; + BN_with_flags(pr1, r1, BN_FLG_CONSTTIME); + + if (!BN_mod(r0, pr1, rsa->p, ctx)) { + goto err; + } + + /* If p < q it is occasionally possible for the correction of + * adding 'p' if r0 is negative above to leave the result still + * negative. This can break the private key operations: the following + * second correction should *always* correct this rare occurrence. + * This will *never* happen with OpenSSL generated keys because + * they ensure p > q [steve] */ + if (BN_is_negative(r0)) { + if (!BN_add(r0, r0, rsa->p)) { + goto err; + } + } + if (!BN_mul(r1, r0, rsa->q, ctx)) { + goto err; + } + if (!BN_add(r0, r1, m1)) { + goto err; + } + + 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(vrfy, vrfy, rsa->n, ctx)) { + goto err; + } + if (BN_is_negative(vrfy)) { + if (!BN_add(vrfy, vrfy, rsa->n)) { + goto err; + } + } + if (!BN_is_zero(vrfy)) { + /* 'I' and 'vrfy' aren't congruent mod n. Don't leak + * miscalculated CRT output, just do a raw (slower) + * mod_exp and return that instead. */ + + BIGNUM local_d; + BIGNUM *d = NULL; + + d = &local_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 keygen(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb) { + BIGNUM *r0 = NULL, *r1 = NULL, *r2 = NULL, *r3 = NULL, *tmp; + BIGNUM local_r0, local_d, local_p; + BIGNUM *pr0, *d, *p; + int bitsp, bitsq, ok = -1, n = 0; + BN_CTX *ctx = NULL; + + 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 (r3 == NULL) { + goto err; + } + + bitsp = (bits + 1) / 2; + bitsq = bits - bitsp; + + /* 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; + + BN_copy(rsa->e, e_value); + + /* generate p and q */ + for (;;) { + if (!BN_generate_prime_ex(rsa->p, bitsp, 0, NULL, NULL, cb)) + goto err; + if (!BN_sub(r2, rsa->p, BN_value_one())) + goto err; + if (!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; + 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, bitsq, 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, keygen, RSA_R_KEY_SIZE_TOO_SMALL); + goto err; + } + if (!BN_sub(r2, rsa->q, BN_value_one())) + goto err; + if (!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)) + goto err; + if (BN_cmp(rsa->p, rsa->q) < 0) { + tmp = rsa->p; + rsa->p = rsa->q; + rsa->q = tmp; + } + + /* calculate n */ + if (!BN_mul(rsa->n, rsa->p, rsa->q, ctx)) + goto err; + + /* 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) */ + pr0 = &local_r0; + BN_with_flags(pr0, r0, BN_FLG_CONSTTIME); + if (!BN_mod_inverse(rsa->d, rsa->e, pr0, ctx)) + goto err; /* d */ + + /* set up d for correct BN_FLG_CONSTTIME flag */ + d = &local_d; + BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME); + + /* calculate d mod (p-1) */ + if (!BN_mod(rsa->dmp1, d, r1, ctx)) + goto err; + + /* calculate d mod (q-1) */ + if (!BN_mod(rsa->dmq1, d, r2, ctx)) + goto err; + + /* calculate inverse of q mod p */ + p = &local_p; + BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME); + + if (!BN_mod_inverse(rsa->iqmp, rsa->q, p, ctx)) + goto err; + + ok = 1; + +err: + if (ok == -1) { + OPENSSL_PUT_ERROR(RSA, keygen, ERR_LIB_BN); + ok = 0; + } + if (ctx != NULL) { + BN_CTX_end(ctx); + BN_CTX_free(ctx); + } + + return ok; +} + +const struct rsa_meth_st RSA_default_method = { + { + 0 /* references */, + 1 /* is_static */, + }, + NULL /* app_data */, + + NULL /* init */, + finish, + + size, + + NULL /* sign */, + NULL /* verify */, + + encrypt, + sign_raw, + decrypt, + verify_raw, + + private_transform, + + mod_exp /* mod_exp */, + BN_mod_exp_mont /* bn_mod_exp */, + + RSA_FLAG_CACHE_PUBLIC | RSA_FLAG_CACHE_PRIVATE, + + keygen, +}; |