/*
- * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
*
- * Licensed under the OpenSSL license (the "License"). You may not use
+ * Licensed under the Apache License 2.0 (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
* Geoff
*/
+/*
+ * RSA low level APIs are deprecated for public use, but still ok for
+ * internal use.
+ */
+#include "internal/deprecated.h"
+
#include <stdio.h>
#include <time.h>
#include "internal/cryptlib.h"
#include <openssl/bn.h>
-#include "rsa_locl.h"
+#include <openssl/self_test.h>
+#include "rsa_local.h"
-static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value,
- BN_GENCB *cb);
+static int rsa_keygen_pairwise_test(RSA *rsa, OSSL_CALLBACK *cb, void *cbarg);
+static int rsa_keygen(OPENSSL_CTX *libctx, RSA *rsa, int bits, int primes,
+ BIGNUM *e_value, BN_GENCB *cb, int pairwise_test);
/*
* NB: this wrapper would normally be placed in rsa_lib.c and the static
*/
int RSA_generate_key_ex(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb)
{
- if (rsa->meth->rsa_keygen)
+ if (rsa->meth->rsa_keygen != NULL)
return rsa->meth->rsa_keygen(rsa, bits, e_value, cb);
- return rsa_builtin_keygen(rsa, bits, e_value, cb);
+
+ return RSA_generate_multi_prime_key(rsa, bits, RSA_DEFAULT_PRIME_NUM,
+ e_value, cb);
}
-static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value,
- BN_GENCB *cb)
+int RSA_generate_multi_prime_key(RSA *rsa, int bits, int primes,
+ BIGNUM *e_value, BN_GENCB *cb)
{
- BIGNUM *r0 = NULL, *r1 = NULL, *r2 = NULL, *r3 = NULL, *tmp;
- int bitsp, bitsq, ok = -1, n = 0;
+#ifndef FIPS_MODULE
+ /* 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;
+ }
+#endif /* FIPS_MODUKE */
+ return rsa_keygen(rsa->libctx, rsa, bits, primes, e_value, cb, 0);
+}
+
+#ifndef FIPS_MODULE
+static int rsa_multiprime_keygen(RSA *rsa, int bits, int primes,
+ BIGNUM *e_value, BN_GENCB *cb)
+{
+ BIGNUM *r0 = NULL, *r1 = NULL, *r2 = NULL, *tmp, *prime;
+ int 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;
+ int ok = -1;
+
+ if (bits < RSA_MIN_MODULUS_BITS) {
+ ok = 0; /* we set our own err */
+ RSAerr(0, RSA_R_KEY_SIZE_TOO_SMALL);
+ goto err;
+ }
+
+ /* A bad value for e can cause infinite loops */
+ if (e_value != NULL && !rsa_check_public_exponent(e_value)) {
+ RSAerr(0, RSA_R_PUB_EXPONENT_OUT_OF_RANGE);
+ return 0;
+ }
+
+ if (primes < RSA_DEFAULT_PRIME_NUM || primes > rsa_multip_cap(bits)) {
+ ok = 0; /* we set our own err */
+ RSAerr(0, RSA_R_KEY_PRIME_NUM_INVALID);
+ goto err;
+ }
ctx = BN_CTX_new();
if (ctx == NULL)
r0 = BN_CTX_get(ctx);
r1 = BN_CTX_get(ctx);
r2 = BN_CTX_get(ctx);
- r3 = BN_CTX_get(ctx);
- if (r3 == NULL)
+ if (r2 == NULL)
goto err;
- bitsp = (bits + 1) / 2;
- bitsq = bits - bitsp;
+ /* 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;
+
+ rsa->dirty_cnt++;
/* 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;
+ BN_set_flags(rsa->d, BN_FLG_CONSTTIME);
if (!rsa->e && ((rsa->e = BN_new()) == NULL))
goto err;
if (!rsa->p && ((rsa->p = BN_secure_new()) == NULL))
goto err;
+ BN_set_flags(rsa->p, BN_FLG_CONSTTIME);
if (!rsa->q && ((rsa->q = BN_secure_new()) == NULL))
goto err;
+ BN_set_flags(rsa->q, BN_FLG_CONSTTIME);
if (!rsa->dmp1 && ((rsa->dmp1 = BN_secure_new()) == NULL))
goto err;
+ BN_set_flags(rsa->dmp1, BN_FLG_CONSTTIME);
if (!rsa->dmq1 && ((rsa->dmq1 = BN_secure_new()) == NULL))
goto err;
+ BN_set_flags(rsa->dmq1, BN_FLG_CONSTTIME);
if (!rsa->iqmp && ((rsa->iqmp = BN_secure_new()) == NULL))
goto err;
+ BN_set_flags(rsa->iqmp, BN_FLG_CONSTTIME);
- 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++))
+ /* 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_GENCB_call(cb, 3, 0))
+
+ if (BN_copy(rsa->e, e_value) == NULL)
goto err;
- for (;;) {
+
+ /* 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;
+ }
/*
- * 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.
+ * 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.
*/
- 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 */
- RSAerr(RSA_F_RSA_BUILTIN_KEYGEN, RSA_R_KEY_SIZE_TOO_SMALL);
+ 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 efficient 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;
}
- if (!BN_sub(r2, rsa->q, BN_value_one()))
+ /* 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_gcd(r1, r2, rsa->e, ctx))
+ if (BN_copy(rsa->n, r1) == NULL)
goto err;
- if (BN_is_one(r1))
- break;
- if (!BN_GENCB_call(cb, 2, n++))
+ if (!BN_GENCB_call(cb, 3, i))
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 */
+
+ /* p - 1 */
if (!BN_sub(r1, rsa->p, BN_value_one()))
- goto err; /* p-1 */
+ goto err;
+ /* q - 1 */
if (!BN_sub(r2, rsa->q, BN_value_one()))
- goto err; /* q-1 */
+ goto err;
+ /* (p - 1)(q - 1) */
if (!BN_mul(r0, r1, r2, ctx))
- goto err; /* (p-1)(q-1) */
+ 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);
if (d == NULL)
goto err;
+
BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
- if ( /* calculate d mod (p-1) */
- !BN_mod(rsa->dmp1, d, r1, ctx)
- /* calculate d mod (q-1) */
+ /* 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);
}
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);
+ RSAerr(0, ERR_LIB_BN);
ok = 0;
}
- if (ctx != NULL)
- BN_CTX_end(ctx);
+ BN_CTX_end(ctx);
BN_CTX_free(ctx);
+ return ok;
+}
+#endif /* FIPS_MODULE */
+
+static int rsa_keygen(OPENSSL_CTX *libctx, RSA *rsa, int bits, int primes,
+ BIGNUM *e_value, BN_GENCB *cb, int pairwise_test)
+{
+ int ok = 0;
+ /*
+ * Only multi-prime keys or insecure keys with a small key length will use
+ * the older rsa_multiprime_keygen().
+ */
+ if (primes == 2 && bits >= 2048)
+ ok = rsa_sp800_56b_generate_key(rsa, bits, e_value, cb);
+#ifndef FIPS_MODULE
+ else
+ ok = rsa_multiprime_keygen(rsa, bits, primes, e_value, cb);
+#endif /* FIPS_MODULE */
+
+#ifdef FIPS_MODULE
+ pairwise_test = 1; /* FIPS MODE needs to always run the pairwise test */
+#endif
+ if (pairwise_test && ok > 0) {
+ OSSL_CALLBACK *stcb = NULL;
+ void *stcbarg = NULL;
+
+ OSSL_SELF_TEST_get_callback(libctx, &stcb, &stcbarg);
+ ok = rsa_keygen_pairwise_test(rsa, stcb, stcbarg);
+ if (!ok) {
+ /* Clear intermediate results */
+ BN_clear_free(rsa->d);
+ BN_clear_free(rsa->p);
+ BN_clear_free(rsa->q);
+ BN_clear_free(rsa->dmp1);
+ BN_clear_free(rsa->dmq1);
+ BN_clear_free(rsa->iqmp);
+ }
+ }
return ok;
}
+
+/*
+ * For RSA key generation it is not known whether the key pair will be used
+ * for key transport or signatures. FIPS 140-2 IG 9.9 states that in this case
+ * either a signature verification OR an encryption operation may be used to
+ * perform the pairwise consistency check. The simpler encrypt/decrypt operation
+ * has been chosen for this case.
+ */
+static int rsa_keygen_pairwise_test(RSA *rsa, OSSL_CALLBACK *cb, void *cbarg)
+{
+ int ret = 0;
+ unsigned int ciphertxt_len;
+ unsigned char *ciphertxt = NULL;
+ const unsigned char plaintxt[16] = {0};
+ unsigned char decoded[256];
+ unsigned int decoded_len;
+ unsigned int plaintxt_len = (unsigned int)sizeof(plaintxt_len);
+ int padding = RSA_PKCS1_PADDING;
+ OSSL_SELF_TEST *st = NULL;
+
+ st = OSSL_SELF_TEST_new(cb, cbarg);
+ if (st == NULL)
+ goto err;
+ OSSL_SELF_TEST_onbegin(st, OSSL_SELF_TEST_TYPE_PCT,
+ OSSL_SELF_TEST_DESC_PCT_RSA_PKCS1);
+
+ ciphertxt_len = RSA_size(rsa);
+ ciphertxt = OPENSSL_zalloc(ciphertxt_len);
+ if (ciphertxt == NULL)
+ goto err;
+
+ ciphertxt_len = RSA_public_encrypt(plaintxt_len, plaintxt, ciphertxt, rsa,
+ padding);
+ if (ciphertxt_len <= 0)
+ goto err;
+ if (ciphertxt_len == plaintxt_len
+ && memcmp(ciphertxt, plaintxt, plaintxt_len) == 0)
+ goto err;
+
+ OSSL_SELF_TEST_oncorrupt_byte(st, ciphertxt);
+
+ decoded_len = RSA_private_decrypt(ciphertxt_len, ciphertxt, decoded, rsa,
+ padding);
+ if (decoded_len != plaintxt_len
+ || memcmp(decoded, plaintxt, decoded_len) != 0)
+ goto err;
+
+ ret = 1;
+err:
+ OSSL_SELF_TEST_onend(st, ret);
+ OSSL_SELF_TEST_free(st);
+ OPENSSL_free(ciphertxt);
+
+ return ret;
+}