/* 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 #include #include #include #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); BIGNUM *f, *result; uint8_t *buf = NULL; BN_CTX *ctx = NULL; unsigned blinding_index = 0; BN_BLINDING *blinding = NULL; int i, ret = 0; if (max_out < rsa_size) { OPENSSL_PUT_ERROR(RSA, sign_raw, RSA_R_OUTPUT_BUFFER_TOO_SMALL); 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, 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 (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, sign_raw, 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, sign_raw, 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, rsa_size, result)) { OPENSSL_PUT_ERROR(RSA, sign_raw, 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); } if (blinding != NULL) { rsa_blinding_release(rsa, blinding, blinding_index); } 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); BIGNUM *f, *result; int r = -1; uint8_t *buf = NULL; BN_CTX *ctx = NULL; unsigned blinding_index; BN_BLINDING *blinding = NULL; int ret = 0; if (max_out < rsa_size) { OPENSSL_PUT_ERROR(RSA, decrypt, RSA_R_OUTPUT_BUFFER_TOO_SMALL); 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, decrypt, ERR_R_MALLOC_FAILURE); goto err; } /* This check was for equality but PGP does evil things * and chops off the top '0' bytes. * TODO(fork): investigate this. */ if (in_len > rsa_size) { OPENSSL_PUT_ERROR(RSA, decrypt, RSA_R_DATA_GREATER_THAN_MOD_LEN); goto err; } /* make data into a big number */ if (BN_bin2bn(in, (int)in_len, f) == NULL) { goto err; } if (BN_ucmp(f, rsa->n) >= 0) { OPENSSL_PUT_ERROR(RSA, decrypt, 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, decrypt, ERR_R_INTERNAL_ERROR); goto err; } if (!BN_BLINDING_convert_ex(f, NULL, blinding, 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->mod_exp(result, f, rsa, ctx)) { goto err; } } else { BIGNUM local_d; BIGNUM *d = NULL; 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(buf, rsa_size, result)) { 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 (ctx != NULL) { BN_CTX_end(ctx); BN_CTX_free(ctx); } if (buf != NULL) { OPENSSL_cleanse(buf, rsa_size); OPENSSL_free(buf); } if (blinding != NULL) { rsa_blinding_release(rsa, blinding, blinding_index); } 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; } /* This check was for equality but PGP does evil things * and chops off the top '0' bytes. * TODO(fork): investigate */ if (in_len > rsa_size) { OPENSSL_PUT_ERROR(RSA, verify_raw, RSA_R_DATA_GREATER_THAN_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 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, mod_exp /* mod_exp */, BN_mod_exp_mont /* bn_mod_exp */, RSA_FLAG_CACHE_PUBLIC | RSA_FLAG_CACHE_PRIVATE, keygen, };