Commit 8240d5fa authored by Shane Lontis's avatar Shane Lontis Committed by Matt Caswell
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FIPS 186-4 RSA Generation & Validation

parent d1229190
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+189 −82
Original line number Diff line number Diff line
/*
 * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
 * Copyright 1995-2019 The OpenSSL Project Authors. All Rights Reserved.
 *
 * 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
@@ -19,14 +19,49 @@
 */
#include "bn_prime.h"

static int witness(BIGNUM *w, const BIGNUM *a, const BIGNUM *a1,
                   const BIGNUM *a1_odd, int k, BN_CTX *ctx,
                   BN_MONT_CTX *mont);
static int probable_prime(BIGNUM *rnd, int bits, prime_t *mods);
static int probable_prime_dh_safe(BIGNUM *rnd, int bits,
                                  const BIGNUM *add, const BIGNUM *rem,
                                  BN_CTX *ctx);

#if BN_BITS2 == 64
# define BN_DEF(lo, hi) (BN_ULONG)hi<<32|lo
#else
# define BN_DEF(lo, hi) lo, hi
#endif

/*
 * See SP800 89 5.3.3 (Step f)
 * The product of the set of primes ranging from 3 to 751
 * Generated using process in test/bn_internal_test.c test_bn_small_factors().
 * This includes 751 (which is not currently included in SP 800-89).
 */
static const BN_ULONG small_prime_factors[] = {
    BN_DEF(0x3ef4e3e1, 0xc4309333), BN_DEF(0xcd2d655f, 0x71161eb6),
    BN_DEF(0x0bf94862, 0x95e2238c), BN_DEF(0x24f7912b, 0x3eb233d3),
    BN_DEF(0xbf26c483, 0x6b55514b), BN_DEF(0x5a144871, 0x0a84d817),
    BN_DEF(0x9b82210a, 0x77d12fee), BN_DEF(0x97f050b3, 0xdb5b93c2),
    BN_DEF(0x4d6c026b, 0x4acad6b9), BN_DEF(0x54aec893, 0xeb7751f3),
    BN_DEF(0x36bc85c4, 0xdba53368), BN_DEF(0x7f5ec78e, 0xd85a1b28),
    BN_DEF(0x6b322244, 0x2eb072d8), BN_DEF(0x5e2b3aea, 0xbba51112),
    BN_DEF(0x0e2486bf, 0x36ed1a6c), BN_DEF(0xec0c5727, 0x5f270460),
    (BN_ULONG)0x000017b1
};

#define BN_SMALL_PRIME_FACTORS_TOP OSSL_NELEM(small_prime_factors)
static const BIGNUM _bignum_small_prime_factors = {
    (BN_ULONG *)small_prime_factors,
    BN_SMALL_PRIME_FACTORS_TOP,
    BN_SMALL_PRIME_FACTORS_TOP,
    0,
    BN_FLG_STATIC_DATA
};

const BIGNUM *bn_get0_small_factors(void)
{
    return &_bignum_small_prime_factors;
}

int BN_GENCB_call(BN_GENCB *cb, int a, int b)
{
    /* No callback means continue */
@@ -148,127 +183,199 @@ int BN_is_prime_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed,
    return BN_is_prime_fasttest_ex(a, checks, ctx_passed, 0, cb);
}

int BN_is_prime_fasttest_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed,
/* See FIPS 186-4 C.3.1 Miller Rabin Probabilistic Primality Test. */
int BN_is_prime_fasttest_ex(const BIGNUM *w, int checks, BN_CTX *ctx_passed,
                            int do_trial_division, BN_GENCB *cb)
{
    int i, j, ret = -1;
    int k;
    int i, status, ret = -1;
    BN_CTX *ctx = NULL;
    BIGNUM *A1, *A1_odd, *A3, *check; /* taken from ctx */
    BN_MONT_CTX *mont = NULL;

    /* Take care of the really small primes 2 & 3 */
    if (BN_is_word(a, 2) || BN_is_word(a, 3))
        return 1;

    /* Check odd and bigger than 1 */
    if (!BN_is_odd(a) || BN_cmp(a, BN_value_one()) <= 0)
    /* w must be bigger than 1 */
    if (BN_cmp(w, BN_value_one()) <= 0)
        return 0;

    if (checks == BN_prime_checks)
        checks = BN_prime_checks_for_size(BN_num_bits(a));
    /* w must be odd */
    if (BN_is_odd(w)) {
        /* Take care of the really small prime 3 */
        if (BN_is_word(w, 3))
            return 1;
    } else {
        /* 2 is the only even prime */
        return BN_is_word(w, 2);
    }

    /* first look for small factors */
    if (do_trial_division) {
        for (i = 1; i < NUMPRIMES; i++) {
            BN_ULONG mod = BN_mod_word(a, primes[i]);
            BN_ULONG mod = BN_mod_word(w, primes[i]);
            if (mod == (BN_ULONG)-1)
                goto err;
                return -1;
            if (mod == 0)
                return BN_is_word(a, primes[i]);
                return BN_is_word(w, primes[i]);
        }
        if (!BN_GENCB_call(cb, 1, -1))
            goto err;
            return -1;
    }

    if (ctx_passed != NULL)
        ctx = ctx_passed;
    else if ((ctx = BN_CTX_new()) == NULL)
        goto err;
    BN_CTX_start(ctx);

    A1 = BN_CTX_get(ctx);
    A3 = BN_CTX_get(ctx);
    A1_odd = BN_CTX_get(ctx);
    check = BN_CTX_get(ctx);
    if (check == NULL)
    ret = bn_miller_rabin_is_prime(w, checks, ctx, cb, 0, &status);
    if (!ret)
        goto err;
    ret = (status == BN_PRIMETEST_PROBABLY_PRIME);
err:
    if (ctx_passed == NULL)
        BN_CTX_free(ctx);
    return ret;
}

    /* compute A1 := a - 1 */
    if (!BN_copy(A1, a) || !BN_sub_word(A1, 1))
/*
 * Refer to FIPS 186-4 C.3.2 Enhanced Miller-Rabin Probabilistic Primality Test.
 * OR C.3.1 Miller-Rabin Probabilistic Primality Test (if enhanced is zero).
 * The Step numbers listed in the code refer to the enhanced case.
 *
 * if enhanced is set, then status returns one of the following:
 *     BN_PRIMETEST_PROBABLY_PRIME
 *     BN_PRIMETEST_COMPOSITE_WITH_FACTOR
 *     BN_PRIMETEST_COMPOSITE_NOT_POWER_OF_PRIME
 * if enhanced is zero, then status returns either
 *     BN_PRIMETEST_PROBABLY_PRIME or
 *     BN_PRIMETEST_COMPOSITE
 *
 * returns 0 if there was an error, otherwise it returns 1.
 */
int bn_miller_rabin_is_prime(const BIGNUM *w, int iterations, BN_CTX *ctx,
                             BN_GENCB *cb, int enhanced, int *status)
{
    int i, j, a, ret = 0;
    BIGNUM *g, *w1, *w3, *x, *m, *z, *b;
    BN_MONT_CTX *mont = NULL;

    /* w must be odd */
    if (!BN_is_odd(w))
        return 0;

    BN_CTX_start(ctx);
    g = BN_CTX_get(ctx);
    w1 = BN_CTX_get(ctx);
    w3 = BN_CTX_get(ctx);
    x = BN_CTX_get(ctx);
    m = BN_CTX_get(ctx);
    z = BN_CTX_get(ctx);
    b = BN_CTX_get(ctx);

    if (!(b != NULL
            /* w1 := w - 1 */
            && BN_copy(w1, w)
            && BN_sub_word(w1, 1)
            /* w3 := w - 3 */
            && BN_copy(w3, w)
            && BN_sub_word(w3, 3)))
        goto err;
    /* compute A3 := a - 3 */
    if (!BN_copy(A3, a) || !BN_sub_word(A3, 3))

    /* check w is larger than 3, otherwise the random b will be too small */
    if (BN_is_zero(w3) || BN_is_negative(w3))
        goto err;

    /* write  A1  as  A1_odd * 2^k */
    k = 1;
    while (!BN_is_bit_set(A1, k))
        k++;
    if (!BN_rshift(A1_odd, A1, k))
    /* (Step 1) Calculate largest integer 'a' such that 2^a divides w-1 */
    a = 1;
    while (!BN_is_bit_set(w1, a))
        a++;
    /* (Step 2) m = (w-1) / 2^a */
    if (!BN_rshift(m, w1, a))
        goto err;

    /* Montgomery setup for computations mod a */
    mont = BN_MONT_CTX_new();
    if (mont == NULL)
        goto err;
    if (!BN_MONT_CTX_set(mont, a, ctx))
    if (mont == NULL || !BN_MONT_CTX_set(mont, w, ctx))
        goto err;

    for (i = 0; i < checks; i++) {
        /* 1 < check < a-1 */
        if (!BN_priv_rand_range(check, A3) || !BN_add_word(check, 2))
    if (iterations == BN_prime_checks)
        iterations = BN_prime_checks_for_size(BN_num_bits(w));

    /* (Step 4) */
    for (i = 0; i < iterations; ++i) {
        /* (Step 4.1) obtain a Random string of bits b where 1 < b < w-1 */
        if (!BN_priv_rand_range(b, w3) || !BN_add_word(b, 2)) /* 1 < b < w-1 */
            goto err;

        j = witness(check, a, A1, A1_odd, k, ctx, mont);
        if (j == -1)
        if (enhanced) {
            /* (Step 4.3) */
            if (!BN_gcd(g, b, w, ctx))
                goto err;
        if (j) {
            ret = 0;
            /* (Step 4.4) */
            if (!BN_is_one(g)) {
                *status = BN_PRIMETEST_COMPOSITE_WITH_FACTOR;
                ret = 1;
                goto err;
            }
        }
        /* (Step 4.5) z = b^m mod w */
        if (!BN_mod_exp_mont(z, b, m, w, ctx, mont))
            goto err;
        /* (Step 4.6) if (z = 1 or z = w-1) */
        if (BN_is_one(z) || BN_cmp(z, w1) == 0)
            goto outer_loop;
        /* (Step 4.7) for j = 1 to a-1 */
        for (j = 1; j < a ; ++j) {
            /* (Step 4.7.1 - 4.7.2) x = z. z = x^2 mod w */
            if (!BN_copy(x, z) || !BN_mod_mul(z, x, x, w, ctx))
                goto err;
            /* (Step 4.7.3) */
            if (BN_cmp(z, w1) == 0)
                goto outer_loop;
            /* (Step 4.7.4) */
            if (BN_is_one(z))
                goto composite;
        }
        if (!BN_GENCB_call(cb, 1, i))
            goto err;
        /* At this point z = b^((w-1)/2) mod w */
        /* (Steps 4.8 - 4.9) x = z, z = x^2 mod w */
        if (!BN_copy(x, z) || !BN_mod_mul(z, x, x, w, ctx))
            goto err;
        /* (Step 4.10) */
        if (BN_is_one(z))
            goto composite;
        /* (Step 4.11) x = b^(w-1) mod w */
        if (!BN_copy(x, z))
            goto err;
composite:
        if (enhanced) {
            /* (Step 4.1.2) g = GCD(x-1, w) */
            if (!BN_sub_word(x, 1) || !BN_gcd(g, x, w, ctx))
                goto err;
            /* (Steps 4.1.3 - 4.1.4) */
            if (BN_is_one(g))
                *status = BN_PRIMETEST_COMPOSITE_NOT_POWER_OF_PRIME;
            else
                *status = BN_PRIMETEST_COMPOSITE_WITH_FACTOR;
        } else {
            *status = BN_PRIMETEST_COMPOSITE;
        }
        ret = 1;
        goto err;
outer_loop: ;
        /* (Step 4.1.5) */
    }
    /* (Step 5) */
    *status = BN_PRIMETEST_PROBABLY_PRIME;
    ret = 1;
err:
    if (ctx != NULL) {
    BN_clear(g);
    BN_clear(w1);
    BN_clear(w3);
    BN_clear(x);
    BN_clear(m);
    BN_clear(z);
    BN_clear(b);
    BN_CTX_end(ctx);
        if (ctx_passed == NULL)
            BN_CTX_free(ctx);
    }
    BN_MONT_CTX_free(mont);

    return ret;
}

static int witness(BIGNUM *w, const BIGNUM *a, const BIGNUM *a1,
                   const BIGNUM *a1_odd, int k, BN_CTX *ctx,
                   BN_MONT_CTX *mont)
{
    if (!BN_mod_exp_mont(w, w, a1_odd, a, ctx, mont)) /* w := w^a1_odd mod a */
        return -1;
    if (BN_is_one(w))
        return 0;               /* probably prime */
    if (BN_cmp(w, a1) == 0)
        return 0;               /* w == -1 (mod a), 'a' is probably prime */
    while (--k) {
        if (!BN_mod_mul(w, w, w, a, ctx)) /* w := w^2 mod a */
            return -1;
        if (BN_is_one(w))
            return 1;           /* 'a' is composite, otherwise a previous 'w'
                                 * would have been == -1 (mod 'a') */
        if (BN_cmp(w, a1) == 0)
            return 0;           /* w == -1 (mod a), 'a' is probably prime */
    }
    /*
     * If we get here, 'w' is the (a-1)/2-th power of the original 'w', and
     * it is neither -1 nor +1 -- so 'a' cannot be prime
     */
    bn_check_top(w);
    return 1;
}

static int probable_prime(BIGNUM *rnd, int bits, prime_t *mods)
{
    int i;
+346 −0
Original line number Diff line number Diff line
/*
 * Copyright 2018-2019 The OpenSSL Project Authors. All Rights Reserved.
 * Copyright (c) 2018-2019, Oracle and/or its affiliates.  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
 */

/*
 * According to NIST SP800-131A "Transitioning the use of cryptographic
 * algorithms and key lengths" Generation of 1024 bit RSA keys are no longer
 * allowed for signatures (Table 2) or key transport (Table 5). In the code
 * below any attempt to generate 1024 bit RSA keys will result in an error (Note
 * that digital signature verification can still use deprecated 1024 bit keys).
 *
 * Also see FIPS1402IG A.14
 * FIPS 186-4 relies on the use of the auxiliary primes p1, p2, q1 and q2 that
 * must be generated before the module generates the RSA primes p and q.
 * Table B.1 in FIPS 186-4 specifies, for RSA modulus lengths of 2048 and
 * 3072 bits only, the min/max total length of the auxiliary primes.
 * When implementing the RSA signature generation algorithm
 * with other approved RSA modulus sizes, the vendor shall use the limitations
 * from Table B.1 that apply to the longest RSA modulus shown in Table B.1 of
 * FIPS 186-4 whose length does not exceed that of the implementation's RSA
 * modulus. In particular, when generating the primes for the 4096-bit RSA
 * modulus the limitations stated for the 3072-bit modulus shall apply.
 */
#include <stdio.h>
#include <openssl/bn.h>
#include "bn_lcl.h"
#include "internal/bn_int.h"

/*
 * FIPS 186-4 Table B.1. "Min length of auxiliary primes p1, p2, q1, q2".
 *
 * Params:
 *     nbits The key size in bits.
 * Returns:
 *     The minimum size of the auxiliary primes or 0 if nbits is invalid.
 */
static int bn_rsa_fips186_4_aux_prime_min_size(int nbits)
{
    if (nbits >= 3072)
        return 171;
    if (nbits == 2048)
        return 141;
    return 0;
}

/*
 * FIPS 186-4 Table B.1 "Maximum length of len(p1) + len(p2) and
 * len(q1) + len(q2) for p,q Probable Primes".
 *
 * Params:
 *     nbits The key size in bits.
 * Returns:
 *     The maximum length or 0 if nbits is invalid.
 */
static int bn_rsa_fips186_4_aux_prime_max_sum_size_for_prob_primes(int nbits)
{
    if (nbits >= 3072)
        return 1518;
    if (nbits == 2048)
        return 1007;
    return 0;
}

/*
 * FIPS 186-4 Table C.3 for error probability of 2^-100
 * Minimum number of Miller Rabin Rounds for p1, p2, q1 & q2.
 *
 * Params:
 *     aux_prime_bits The auxiliary prime size in bits.
 * Returns:
 *     The minimum number of Miller Rabin Rounds for an auxiliary prime, or
 *     0 if aux_prime_bits is invalid.
 */
static int bn_rsa_fips186_4_aux_prime_MR_min_checks(int aux_prime_bits)
{
    if (aux_prime_bits > 170)
        return 27;
    if (aux_prime_bits > 140)
        return 32;
    return 0; /* Error case */
}

/*
 * FIPS 186-4 Table C.3 for error probability of 2^-100
 * Minimum number of Miller Rabin Rounds for p, q.
 *
 * Params:
 *     nbits The key size in bits.
 * Returns:
 *     The minimum number of Miller Rabin Rounds required,
 *     or 0 if nbits is invalid.
 */
int bn_rsa_fips186_4_prime_MR_min_checks(int nbits)
{
    if (nbits >= 3072) /* > 170 */
        return 3;
    if (nbits == 2048) /* > 140 */
        return 4;
    return 0; /* Error case */
}

/*
 * Find the first odd integer that is a probable prime.
 *
 * See section FIPS 186-4 B.3.6 (Steps 4.2/5.2).
 *
 * Params:
 *     Xp1 The passed in starting point to find a probably prime.
 *     p1 The returned probable prime (first odd integer >= Xp1)
 *     ctx A BN_CTX object.
 *     cb An optional BIGNUM callback.
 * Returns: 1 on success otherwise it returns 0.
 */
static int bn_rsa_fips186_4_find_aux_prob_prime(const BIGNUM *Xp1,
                                                BIGNUM *p1, BN_CTX *ctx,
                                                BN_GENCB *cb)
{
    int ret = 0;
    int i = 0;
    int checks = bn_rsa_fips186_4_aux_prime_MR_min_checks(BN_num_bits(Xp1));

    if (checks == 0 || BN_copy(p1, Xp1) == NULL)
        return 0;

    /* Find the first odd number >= Xp1 that is probably prime */
    for(;;) {
        i++;
        BN_GENCB_call(cb, 0, i);
        /* MR test with trial division */
        if (BN_is_prime_fasttest_ex(p1, checks, ctx, 1, cb))
            break;
        /* Get next odd number */
        if (!BN_add_word(p1, 2))
            goto err;
    }
    BN_GENCB_call(cb, 2, i);
    ret = 1;
err:
    return ret;
}

/*
 * Generate a probable prime (p or q).
 *
 * See FIPS 186-4 B.3.6 (Steps 4 & 5)
 *
 * Params:
 *     p The returned probable prime.
 *     Xpout An optionally returned random number used during generation of p.
 *     p1, p2 The returned auxiliary primes. If NULL they are not returned.
 *     Xp An optional passed in value (that is random number used during
 *        generation of p).
 *     Xp1, Xp2 Optional passed in values that are normally generated
 *              internally. Used to find p1, p2.
 *     nlen The bit length of the modulus (the key size).
 *     e The public exponent.
 *     ctx A BN_CTX object.
 *     cb An optional BIGNUM callback.
 * Returns: 1 on success otherwise it returns 0.
 */
int bn_rsa_fips186_4_gen_prob_primes(BIGNUM *p, BIGNUM *Xpout,
                                     BIGNUM *p1, BIGNUM *p2,
                                     const BIGNUM *Xp, const BIGNUM *Xp1,
                                     const BIGNUM *Xp2, int nlen,
                                     const BIGNUM *e, BN_CTX *ctx, BN_GENCB *cb)
{
    int ret = 0;
    BIGNUM *p1i = NULL, *p2i = NULL, *Xp1i = NULL, *Xp2i = NULL;
    int bitlen;

    if (p == NULL || Xpout == NULL)
        return 0;

    BN_CTX_start(ctx);

    p1i = (p1 != NULL) ? p1 : BN_CTX_get(ctx);
    p2i = (p2 != NULL) ? p2 : BN_CTX_get(ctx);
    Xp1i = (Xp1 != NULL) ? (BIGNUM *)Xp1 : BN_CTX_get(ctx);
    Xp2i = (Xp2 != NULL) ? (BIGNUM *)Xp2 : BN_CTX_get(ctx);
    if (p1i == NULL || p2i == NULL || Xp1i == NULL || Xp2i == NULL)
        goto err;

    bitlen = bn_rsa_fips186_4_aux_prime_min_size(nlen);
    if (bitlen == 0)
        goto err;

    /* (Steps 4.1/5.1): Randomly generate Xp1 if it is not passed in */
    if (Xp1 == NULL) {
        /* Set the top and bottom bits to make it odd and the correct size */
        if (!BN_priv_rand(Xp1i, bitlen, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD))
            goto err;
    }
    /* (Steps 4.1/5.1): Randomly generate Xp2 if it is not passed in */
    if (Xp2 == NULL) {
        /* Set the top and bottom bits to make it odd and the correct size */
        if (!BN_priv_rand(Xp2i, bitlen, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD))
            goto err;
    }

    /* (Steps 4.2/5.2) - find first auxiliary probable primes */
    if (!bn_rsa_fips186_4_find_aux_prob_prime(Xp1i, p1i, ctx, cb)
            || !bn_rsa_fips186_4_find_aux_prob_prime(Xp2i, p2i, ctx, cb))
        goto err;
    /* (Table B.1) auxiliary prime Max length check */
    if ((BN_num_bits(p1i) + BN_num_bits(p2i)) >=
            bn_rsa_fips186_4_aux_prime_max_sum_size_for_prob_primes(nlen))
        goto err;
    /* (Steps 4.3/5.3) - generate prime */
    if (!bn_rsa_fips186_4_derive_prime(p, Xpout, Xp, p1i, p2i, nlen, e, ctx, cb))
        goto err;
    ret = 1;
err:
    /* Zeroize any internally generated values that are not returned */
    if (p1 == NULL)
        BN_clear(p1i);
    if (p2 == NULL)
        BN_clear(p2i);
    if (Xp1 == NULL)
        BN_clear(Xp1i);
    if (Xp2 == NULL)
        BN_clear(Xp2i);
    BN_CTX_end(ctx);
    return ret;
}

/*
 * Constructs a probable prime (a candidate for p or q) using 2 auxiliary
 * prime numbers and the Chinese Remainder Theorem.
 *
 * See FIPS 186-4 C.9 "Compute a Probable Prime Factor Based on Auxiliary
 * Primes". Used by FIPS 186-4 B.3.6 Section (4.3) for p and Section (5.3) for q.
 *
 * Params:
 *     Y The returned prime factor (private_prime_factor) of the modulus n.
 *     X The returned random number used during generation of the prime factor.
 *     Xin An optional passed in value for X used for testing purposes.
 *     r1 An auxiliary prime.
 *     r2 An auxiliary prime.
 *     nlen The desired length of n (the RSA modulus).
 *     e The public exponent.
 *     ctx A BN_CTX object.
 *     cb An optional BIGNUM callback object.
 * Returns: 1 on success otherwise it returns 0.
 * Assumptions:
 *     Y, X, r1, r2, e are not NULL.
 */
int bn_rsa_fips186_4_derive_prime(BIGNUM *Y, BIGNUM *X, const BIGNUM *Xin,
                                  const BIGNUM *r1, const BIGNUM *r2, int nlen,
                                  const BIGNUM *e, BN_CTX *ctx, BN_GENCB *cb)
{
    int ret = 0;
    int i, imax;
    int bits = nlen >> 1;
    int checks = bn_rsa_fips186_4_prime_MR_min_checks(nlen);
    BIGNUM *tmp, *R, *r1r2x2, *y1, *r1x2;

    if (checks == 0)
        return 0;
    BN_CTX_start(ctx);

    R = BN_CTX_get(ctx);
    tmp = BN_CTX_get(ctx);
    r1r2x2 = BN_CTX_get(ctx);
    y1 = BN_CTX_get(ctx);
    r1x2 = BN_CTX_get(ctx);
    if (r1x2 == NULL)
        goto err;

    if (Xin != NULL && BN_copy(X, Xin) == NULL)
        goto err;

    if (!(BN_lshift1(r1x2, r1)
            /* (Step 1) GCD(2r1, r2) = 1 */
            && BN_gcd(tmp, r1x2, r2, ctx)
            && BN_is_one(tmp)
            /* (Step 2) R = ((r2^-1 mod 2r1) * r2) - ((2r1^-1 mod r2)*2r1) */
            && BN_mod_inverse(R, r2, r1x2, ctx)
            && BN_mul(R, R, r2, ctx) /* R = (r2^-1 mod 2r1) * r2 */
            && BN_mod_inverse(tmp, r1x2, r2, ctx)
            && BN_mul(tmp, tmp, r1x2, ctx) /* tmp = (2r1^-1 mod r2)*2r1 */
            && BN_sub(R, R, tmp)
            /* Calculate 2r1r2 */
            && BN_mul(r1r2x2, r1x2, r2, ctx)))
        goto err;
    /* Make positive by adding the modulus */
    if (BN_is_negative(R) && !BN_add(R, R, r1r2x2))
        goto err;

    imax = 5 * bits; /* max = 5/2 * nbits */
    for (;;) {
        if (Xin == NULL) {
            /*
             * (Step 3) Choose Random X such that
             *    sqrt(2) * 2^(nlen/2-1) < Random X < (2^(nlen/2)) - 1.
             *
             * For the lower bound:
             *   sqrt(2) * 2^(nlen/2 - 1) == sqrt(2)/2 * 2^(nlen/2)
             *   where sqrt(2)/2 = 0.70710678.. = 0.B504FC33F9DE...
             *   so largest number will have B5... as the top byte
             *   Setting the top 2 bits gives 0xC0.
             */
            if (!BN_priv_rand(X, bits, BN_RAND_TOP_TWO, BN_RAND_BOTTOM_ANY))
                goto end;
        }
        /* (Step 4) Y = X + ((R - X) mod 2r1r2) */
        if (!BN_mod_sub(Y, R, X, r1r2x2, ctx) || !BN_add(Y, Y, X))
            goto err;
        /* (Step 5) */
        i = 0;
        for (;;) {
            /* (Step 6) */
            if (BN_num_bits(Y) > bits) {
                if (Xin == NULL)
                    break; /* Randomly Generated X so Go back to Step 3 */
                else
                    goto err; /* X is not random so it will always fail */
            }
            BN_GENCB_call(cb, 0, 2);

            /* (Step 7) If GCD(Y-1) == 1 & Y is probably prime then return Y */
            if (BN_copy(y1, Y) == NULL
                    || !BN_sub_word(y1, 1)
                    || !BN_gcd(tmp, y1, e, ctx))
                goto err;
            if (BN_is_one(tmp)
                    && BN_is_prime_fasttest_ex(Y, checks, ctx, 1, cb))
                goto end;
            /* (Step 8-10) */
            if (++i >= imax || !BN_add(Y, Y, r1r2x2))
                goto err;
        }
    }
end:
    ret = 1;
    BN_GENCB_call(cb, 3, 0);
err:
    BN_clear(y1);
    BN_CTX_end(ctx);
    return ret;
}
+2 −1
Original line number Diff line number Diff line
@@ -5,7 +5,8 @@ SOURCE[../../libcrypto]=\
        bn_kron.c bn_sqrt.c bn_gcd.c bn_prime.c bn_err.c bn_sqr.c \
        {- $target{bn_asm_src} -} \
        bn_recp.c bn_mont.c bn_mpi.c bn_exp2.c bn_gf2m.c bn_nist.c \
        bn_depr.c bn_const.c bn_x931p.c bn_intern.c bn_dh.c bn_srp.c
        bn_depr.c bn_const.c bn_x931p.c bn_intern.c bn_dh.c bn_srp.c \
        bn_rsa_fips186_4.c
INCLUDE[../../libcrypto]=../../crypto/include

INCLUDE[bn_exp.o]=..
+27 −0
Original line number Diff line number Diff line
@@ -87,4 +87,31 @@ int bn_rshift_fixed_top(BIGNUM *r, const BIGNUM *a, int n);
int bn_div_fixed_top(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m,
                     const BIGNUM *d, BN_CTX *ctx);

#define BN_PRIMETEST_COMPOSITE                    0
#define BN_PRIMETEST_COMPOSITE_WITH_FACTOR        1
#define BN_PRIMETEST_COMPOSITE_NOT_POWER_OF_PRIME 2
#define BN_PRIMETEST_PROBABLY_PRIME               3

int bn_miller_rabin_is_prime(const BIGNUM *w, int iterations, BN_CTX *ctx,
                             BN_GENCB *cb, int enhanced, int *status);

const BIGNUM *bn_get0_small_factors(void);

int bn_rsa_fips186_4_prime_MR_min_checks(int nbits);

int bn_rsa_fips186_4_gen_prob_primes(BIGNUM *p, BIGNUM *Xpout,
                                     BIGNUM *p1, BIGNUM *p2,
                                     const BIGNUM *Xp, const BIGNUM *Xp1,
                                     const BIGNUM *Xp2, int nlen,
                                     const BIGNUM *e, BN_CTX *ctx,
                                     BN_GENCB *cb);

int bn_rsa_fips186_4_derive_prime(BIGNUM *Y, BIGNUM *X, const BIGNUM *Xin,
                                  const BIGNUM *r1, const BIGNUM *r2, int nlen,
                                  const BIGNUM *e, BN_CTX *ctx, BN_GENCB *cb);

#ifdef  __cplusplus
}
#endif

#endif
+2 −1
Original line number Diff line number Diff line
@@ -3,4 +3,5 @@ SOURCE[../../libcrypto]=\
        rsa_ossl.c rsa_gen.c rsa_lib.c rsa_sign.c rsa_saos.c rsa_err.c \
        rsa_pk1.c rsa_ssl.c rsa_none.c rsa_oaep.c rsa_chk.c \
        rsa_pss.c rsa_x931.c rsa_asn1.c rsa_depr.c rsa_ameth.c rsa_prn.c \
        rsa_pmeth.c rsa_crpt.c rsa_x931g.c rsa_meth.c rsa_mp.c
        rsa_pmeth.c rsa_crpt.c rsa_x931g.c rsa_meth.c rsa_mp.c \
        rsa_sp800_56b_gen.c rsa_sp800_56b_check.c
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