| /* |
| * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved. |
| * |
| * Licensed under the OpenSSL license (the "License"). You may not use |
| * this file except in compliance with the License. You can obtain a copy |
| * in the file LICENSE in the source distribution or at |
| * https://www.openssl.org/source/license.html |
| */ |
| |
| /* |
| * NB: these functions have been "upgraded", the deprecated versions (which |
| * are compatibility wrappers using these functions) are in rsa_depr.c. - |
| * Geoff |
| */ |
| |
| #include <stdio.h> |
| #include <time.h> |
| #include "internal/cryptlib.h" |
| #include <openssl/bn.h> |
| #include "rsa_locl.h" |
| |
| static int rsa_builtin_keygen(RSA *rsa, int bits, int primes, BIGNUM *e_value, |
| BN_GENCB *cb); |
| |
| /* |
| * NB: this wrapper would normally be placed in rsa_lib.c and the static |
| * implementation would probably be in rsa_eay.c. Nonetheless, is kept here |
| * so that we don't introduce a new linker dependency. Eg. any application |
| * that wasn't previously linking object code related to key-generation won't |
| * have to now just because key-generation is part of RSA_METHOD. |
| */ |
| int RSA_generate_key_ex(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb) |
| { |
| if (rsa->meth->rsa_keygen != NULL) |
| return rsa->meth->rsa_keygen(rsa, bits, e_value, cb); |
| |
| return RSA_generate_multi_prime_key(rsa, bits, RSA_DEFAULT_PRIME_NUM, |
| e_value, cb); |
| } |
| |
| int RSA_generate_multi_prime_key(RSA *rsa, int bits, int primes, |
| BIGNUM *e_value, BN_GENCB *cb) |
| { |
| /* multi-prime is only supported with the builtin key generation */ |
| if (rsa->meth->rsa_multi_prime_keygen != NULL) { |
| return rsa->meth->rsa_multi_prime_keygen(rsa, bits, primes, |
| e_value, cb); |
| } else if (rsa->meth->rsa_keygen != NULL) { |
| /* |
| * However, if rsa->meth implements only rsa_keygen, then we |
| * have to honour it in 2-prime case and assume that it wouldn't |
| * know what to do with multi-prime key generated by builtin |
| * subroutine... |
| */ |
| if (primes == 2) |
| return rsa->meth->rsa_keygen(rsa, bits, e_value, cb); |
| else |
| return 0; |
| } |
| |
| return rsa_builtin_keygen(rsa, bits, primes, e_value, cb); |
| } |
| |
| static int rsa_builtin_keygen(RSA *rsa, int bits, int primes, BIGNUM *e_value, |
| BN_GENCB *cb) |
| { |
| BIGNUM *r0 = NULL, *r1 = NULL, *r2 = NULL, *tmp, *prime; |
| int ok = -1, n = 0, bitsr[RSA_MAX_PRIME_NUM], bitse = 0; |
| int i = 0, quo = 0, rmd = 0, adj = 0, retries = 0; |
| RSA_PRIME_INFO *pinfo = NULL; |
| STACK_OF(RSA_PRIME_INFO) *prime_infos = NULL; |
| BN_CTX *ctx = NULL; |
| BN_ULONG bitst = 0; |
| unsigned long error = 0; |
| |
| if (bits < RSA_MIN_MODULUS_BITS) { |
| ok = 0; /* we set our own err */ |
| RSAerr(RSA_F_RSA_BUILTIN_KEYGEN, RSA_R_KEY_SIZE_TOO_SMALL); |
| goto err; |
| } |
| |
| if (primes < RSA_DEFAULT_PRIME_NUM || primes > rsa_multip_cap(bits)) { |
| ok = 0; /* we set our own err */ |
| RSAerr(RSA_F_RSA_BUILTIN_KEYGEN, RSA_R_KEY_PRIME_NUM_INVALID); |
| 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); |
| if (r2 == NULL) |
| goto err; |
| |
| /* divide bits into 'primes' pieces evenly */ |
| quo = bits / primes; |
| rmd = bits % primes; |
| |
| for (i = 0; i < primes; i++) |
| bitsr[i] = (i < rmd) ? quo + 1 : quo; |
| |
| /* We need the RSA components non-NULL */ |
| if (!rsa->n && ((rsa->n = BN_new()) == NULL)) |
| goto err; |
| if (!rsa->d && ((rsa->d = BN_secure_new()) == NULL)) |
| goto err; |
| if (!rsa->e && ((rsa->e = BN_new()) == NULL)) |
| goto err; |
| if (!rsa->p && ((rsa->p = BN_secure_new()) == NULL)) |
| goto err; |
| if (!rsa->q && ((rsa->q = BN_secure_new()) == NULL)) |
| goto err; |
| if (!rsa->dmp1 && ((rsa->dmp1 = BN_secure_new()) == NULL)) |
| goto err; |
| if (!rsa->dmq1 && ((rsa->dmq1 = BN_secure_new()) == NULL)) |
| goto err; |
| if (!rsa->iqmp && ((rsa->iqmp = BN_secure_new()) == NULL)) |
| goto err; |
| |
| /* initialize multi-prime components */ |
| if (primes > RSA_DEFAULT_PRIME_NUM) { |
| rsa->version = RSA_ASN1_VERSION_MULTI; |
| prime_infos = sk_RSA_PRIME_INFO_new_reserve(NULL, primes - 2); |
| if (prime_infos == NULL) |
| goto err; |
| if (rsa->prime_infos != NULL) { |
| /* could this happen? */ |
| sk_RSA_PRIME_INFO_pop_free(rsa->prime_infos, rsa_multip_info_free); |
| } |
| rsa->prime_infos = prime_infos; |
| |
| /* prime_info from 2 to |primes| -1 */ |
| for (i = 2; i < primes; i++) { |
| pinfo = rsa_multip_info_new(); |
| if (pinfo == NULL) |
| goto err; |
| (void)sk_RSA_PRIME_INFO_push(prime_infos, pinfo); |
| } |
| } |
| |
| if (BN_copy(rsa->e, e_value) == NULL) |
| goto err; |
| |
| /* generate p, q and other primes (if any) */ |
| for (i = 0; i < primes; i++) { |
| adj = 0; |
| retries = 0; |
| |
| if (i == 0) { |
| prime = rsa->p; |
| } else if (i == 1) { |
| prime = rsa->q; |
| } else { |
| pinfo = sk_RSA_PRIME_INFO_value(prime_infos, i - 2); |
| prime = pinfo->r; |
| } |
| BN_set_flags(prime, BN_FLG_CONSTTIME); |
| |
| for (;;) { |
| redo: |
| if (!BN_generate_prime_ex(prime, bitsr[i] + adj, 0, NULL, NULL, cb)) |
| goto err; |
| /* |
| * prime should not be equal to p, q, r_3... |
| * (those primes prior to this one) |
| */ |
| { |
| int j; |
| |
| for (j = 0; j < i; j++) { |
| BIGNUM *prev_prime; |
| |
| if (j == 0) |
| prev_prime = rsa->p; |
| else if (j == 1) |
| prev_prime = rsa->q; |
| else |
| prev_prime = sk_RSA_PRIME_INFO_value(prime_infos, |
| j - 2)->r; |
| |
| if (!BN_cmp(prime, prev_prime)) { |
| goto redo; |
| } |
| } |
| } |
| if (!BN_sub(r2, prime, BN_value_one())) |
| goto err; |
| ERR_set_mark(); |
| BN_set_flags(r2, BN_FLG_CONSTTIME); |
| if (BN_mod_inverse(r1, r2, rsa->e, ctx) != NULL) { |
| /* GCD == 1 since inverse exists */ |
| break; |
| } |
| error = ERR_peek_last_error(); |
| if (ERR_GET_LIB(error) == ERR_LIB_BN |
| && ERR_GET_REASON(error) == BN_R_NO_INVERSE) { |
| /* GCD != 1 */ |
| ERR_pop_to_mark(); |
| } else { |
| goto err; |
| } |
| if (!BN_GENCB_call(cb, 2, n++)) |
| goto err; |
| } |
| |
| bitse += bitsr[i]; |
| |
| /* calculate n immediately to see if it's sufficient */ |
| if (i == 1) { |
| /* we get at least 2 primes */ |
| if (!BN_mul(r1, rsa->p, rsa->q, ctx)) |
| goto err; |
| } else if (i != 0) { |
| /* modulus n = p * q * r_3 * r_4 ... */ |
| if (!BN_mul(r1, rsa->n, prime, ctx)) |
| goto err; |
| } else { |
| /* i == 0, do nothing */ |
| if (!BN_GENCB_call(cb, 3, i)) |
| goto err; |
| continue; |
| } |
| /* |
| * if |r1|, product of factors so far, is not as long as expected |
| * (by checking the first 4 bits are less than 0x9 or greater than |
| * 0xF). If so, re-generate the last prime. |
| * |
| * NOTE: This actually can't happen in two-prime case, because of |
| * the way factors are generated. |
| * |
| * Besides, another consideration is, for multi-prime case, even the |
| * length modulus is as long as expected, the modulus could start at |
| * 0x8, which could be utilized to distinguish a multi-prime private |
| * key by using the modulus in a certificate. This is also covered |
| * by checking the length should not be less than 0x9. |
| */ |
| if (!BN_rshift(r2, r1, bitse - 4)) |
| goto err; |
| bitst = BN_get_word(r2); |
| |
| if (bitst < 0x9 || bitst > 0xF) { |
| /* |
| * For keys with more than 4 primes, we attempt longer factor to |
| * meet length requirement. |
| * |
| * Otherwise, we just re-generate the prime with the same length. |
| * |
| * This strategy has the following goals: |
| * |
| * 1. 1024-bit factors are effcient when using 3072 and 4096-bit key |
| * 2. stay the same logic with normal 2-prime key |
| */ |
| bitse -= bitsr[i]; |
| if (!BN_GENCB_call(cb, 2, n++)) |
| goto err; |
| if (primes > 4) { |
| if (bitst < 0x9) |
| adj++; |
| else |
| adj--; |
| } else if (retries == 4) { |
| /* |
| * re-generate all primes from scratch, mainly used |
| * in 4 prime case to avoid long loop. Max retry times |
| * is set to 4. |
| */ |
| i = -1; |
| bitse = 0; |
| continue; |
| } |
| retries++; |
| goto redo; |
| } |
| /* save product of primes for further use, for multi-prime only */ |
| if (i > 1 && BN_copy(pinfo->pp, rsa->n) == NULL) |
| goto err; |
| if (BN_copy(rsa->n, r1) == NULL) |
| goto err; |
| if (!BN_GENCB_call(cb, 3, i)) |
| goto err; |
| } |
| |
| if (BN_cmp(rsa->p, rsa->q) < 0) { |
| tmp = rsa->p; |
| rsa->p = rsa->q; |
| rsa->q = tmp; |
| } |
| |
| /* calculate d */ |
| |
| /* p - 1 */ |
| if (!BN_sub(r1, rsa->p, BN_value_one())) |
| goto err; |
| /* q - 1 */ |
| if (!BN_sub(r2, rsa->q, BN_value_one())) |
| goto err; |
| /* (p - 1)(q - 1) */ |
| if (!BN_mul(r0, r1, r2, ctx)) |
| goto err; |
| /* multi-prime */ |
| for (i = 2; i < primes; i++) { |
| pinfo = sk_RSA_PRIME_INFO_value(prime_infos, i - 2); |
| /* save r_i - 1 to pinfo->d temporarily */ |
| if (!BN_sub(pinfo->d, pinfo->r, BN_value_one())) |
| goto err; |
| if (!BN_mul(r0, r0, pinfo->d, ctx)) |
| goto err; |
| } |
| |
| { |
| BIGNUM *pr0 = BN_new(); |
| |
| if (pr0 == NULL) |
| goto err; |
| |
| BN_with_flags(pr0, r0, BN_FLG_CONSTTIME); |
| if (!BN_mod_inverse(rsa->d, rsa->e, pr0, ctx)) { |
| BN_free(pr0); |
| goto err; /* d */ |
| } |
| /* We MUST free pr0 before any further use of r0 */ |
| BN_free(pr0); |
| } |
| |
| { |
| BIGNUM *d = BN_new(); |
| |
| if (d == NULL) |
| goto err; |
| |
| BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME); |
| |
| /* calculate d mod (p-1) and d mod (q - 1) */ |
| if (!BN_mod(rsa->dmp1, d, r1, ctx) |
| || !BN_mod(rsa->dmq1, d, r2, ctx)) { |
| BN_free(d); |
| goto err; |
| } |
| |
| /* calculate CRT exponents */ |
| for (i = 2; i < primes; i++) { |
| pinfo = sk_RSA_PRIME_INFO_value(prime_infos, i - 2); |
| /* pinfo->d == r_i - 1 */ |
| if (!BN_mod(pinfo->d, d, pinfo->d, ctx)) { |
| BN_free(d); |
| goto err; |
| } |
| } |
| |
| /* We MUST free d before any further use of rsa->d */ |
| BN_free(d); |
| } |
| |
| { |
| BIGNUM *p = BN_new(); |
| |
| if (p == NULL) |
| goto err; |
| BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME); |
| |
| /* calculate inverse of q mod p */ |
| if (!BN_mod_inverse(rsa->iqmp, rsa->q, p, ctx)) { |
| BN_free(p); |
| goto err; |
| } |
| |
| /* calculate CRT coefficient for other primes */ |
| for (i = 2; i < primes; i++) { |
| pinfo = sk_RSA_PRIME_INFO_value(prime_infos, i - 2); |
| BN_with_flags(p, pinfo->r, BN_FLG_CONSTTIME); |
| if (!BN_mod_inverse(pinfo->t, pinfo->pp, p, ctx)) { |
| BN_free(p); |
| goto err; |
| } |
| } |
| |
| /* We MUST free p before any further use of rsa->p */ |
| BN_free(p); |
| } |
| |
| ok = 1; |
| err: |
| if (ok == -1) { |
| RSAerr(RSA_F_RSA_BUILTIN_KEYGEN, ERR_LIB_BN); |
| ok = 0; |
| } |
| if (ctx != NULL) |
| BN_CTX_end(ctx); |
| BN_CTX_free(ctx); |
| return ok; |
| } |
