static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words)
{
    BN_ULONG *a = NULL;
    if (words > (INT_MAX / (4 * BN_BITS2))) {
        BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_BIGNUM_TOO_LONG);
        return NULL;
    }
    if (BN_get_flags(b, BN_FLG_STATIC_DATA)) {
        BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
        return NULL;
    }
    if (BN_get_flags(b, BN_FLG_SECURE))
        a = OPENSSL_secure_zalloc(words * sizeof(*a));
    else
        a = OPENSSL_zalloc(words * sizeof(*a));
    if (a == NULL) {
        BNerr(BN_F_BN_EXPAND_INTERNAL, ERR_R_MALLOC_FAILURE);
        return NULL;
    }
    assert(b->top <= words);
    if (b->top > 0)
        memcpy(a, b->d, sizeof(*a) * b->top);
    return a;
}
['int bn_rsa_fips186_4_derive_prime(BIGNUM *Y, BIGNUM *X, const BIGNUM *Xin,\n                                  const BIGNUM *r1, const BIGNUM *r2, int nlen,\n                                  const BIGNUM *e, BN_CTX *ctx, BN_GENCB *cb)\n{\n    int ret = 0;\n    int i, imax;\n    int bits = nlen >> 1;\n    int checks = bn_rsa_fips186_4_prime_MR_min_checks(nlen);\n    BIGNUM *tmp, *R, *r1r2x2, *y1, *r1x2;\n    if (checks == 0)\n        return 0;\n    BN_CTX_start(ctx);\n    R = BN_CTX_get(ctx);\n    tmp = BN_CTX_get(ctx);\n    r1r2x2 = BN_CTX_get(ctx);\n    y1 = BN_CTX_get(ctx);\n    r1x2 = BN_CTX_get(ctx);\n    if (r1x2 == NULL)\n        goto err;\n    if (Xin != NULL && BN_copy(X, Xin) == NULL)\n        goto err;\n    if (!(BN_lshift1(r1x2, r1)\n            && BN_gcd(tmp, r1x2, r2, ctx)\n            && BN_is_one(tmp)\n            && BN_mod_inverse(R, r2, r1x2, ctx)\n            && BN_mul(R, R, r2, ctx)\n            && BN_mod_inverse(tmp, r1x2, r2, ctx)\n            && BN_mul(tmp, tmp, r1x2, ctx)\n            && BN_sub(R, R, tmp)\n            && BN_mul(r1r2x2, r1x2, r2, ctx)))\n        goto err;\n    if (BN_is_negative(R) && !BN_add(R, R, r1r2x2))\n        goto err;\n    imax = 5 * bits;\n    for (;;) {\n        if (Xin == NULL) {\n            if (!BN_priv_rand(X, bits, BN_RAND_TOP_TWO, BN_RAND_BOTTOM_ANY))\n                goto end;\n        }\n        if (!BN_mod_sub(Y, R, X, r1r2x2, ctx) || !BN_add(Y, Y, X))\n            goto err;\n        i = 0;\n        for (;;) {\n            if (BN_num_bits(Y) > bits) {\n                if (Xin == NULL)\n                    break;\n                else\n                    goto err;\n            }\n            BN_GENCB_call(cb, 0, 2);\n            if (BN_copy(y1, Y) == NULL\n                    || !BN_sub_word(y1, 1)\n                    || !BN_gcd(tmp, y1, e, ctx))\n                goto err;\n            if (BN_is_one(tmp)\n                    && BN_is_prime_fasttest_ex(Y, checks, ctx, 1, cb))\n                goto end;\n            if (++i >= imax || !BN_add(Y, Y, r1r2x2))\n                goto err;\n        }\n    }\nend:\n    ret = 1;\n    BN_GENCB_call(cb, 3, 0);\nerr:\n    BN_clear(y1);\n    BN_CTX_end(ctx);\n    return ret;\n}', 'int BN_lshift1(BIGNUM *r, const BIGNUM *a)\n{\n    register BN_ULONG *ap, *rp, t, c;\n    int i;\n    bn_check_top(r);\n    bn_check_top(a);\n    if (r != a) {\n        r->neg = a->neg;\n        if (bn_wexpand(r, a->top + 1) == NULL)\n            return 0;\n        r->top = a->top;\n    } else {\n        if (bn_wexpand(r, a->top + 1) == NULL)\n            return 0;\n    }\n    ap = a->d;\n    rp = r->d;\n    c = 0;\n    for (i = 0; i < a->top; i++) {\n        t = *(ap++);\n        *(rp++) = ((t << 1) | c) & BN_MASK2;\n        c = (t & BN_TBIT) ? 1 : 0;\n    }\n    if (c) {\n        *rp = 1;\n        r->top++;\n    }\n    bn_check_top(r);\n    return 1;\n}', 'int BN_gcd(BIGNUM *r, const BIGNUM *in_a, const BIGNUM *in_b, BN_CTX *ctx)\n{\n    BIGNUM *a, *b, *t;\n    int ret = 0;\n    bn_check_top(in_a);\n    bn_check_top(in_b);\n    BN_CTX_start(ctx);\n    a = BN_CTX_get(ctx);\n    b = BN_CTX_get(ctx);\n    if (b == NULL)\n        goto err;\n    if (BN_copy(a, in_a) == NULL)\n        goto err;\n    if (BN_copy(b, in_b) == NULL)\n        goto err;\n    a->neg = 0;\n    b->neg = 0;\n    if (BN_cmp(a, b) < 0) {\n        t = a;\n        a = b;\n        b = t;\n    }\n    t = euclid(a, b);\n    if (t == NULL)\n        goto err;\n    if (BN_copy(r, t) == NULL)\n        goto err;\n    ret = 1;\n err:\n    BN_CTX_end(ctx);\n    bn_check_top(r);\n    return ret;\n}', 'BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)\n{\n    bn_check_top(b);\n    if (a == b)\n        return a;\n    if (bn_wexpand(a, b->top) == NULL)\n        return NULL;\n    if (b->top > 0)\n        memcpy(a->d, b->d, sizeof(b->d[0]) * b->top);\n    a->neg = b->neg;\n    a->top = b->top;\n    a->flags |= b->flags & BN_FLG_FIXED_TOP;\n    bn_check_top(a);\n    return a;\n}', 'BIGNUM *bn_wexpand(BIGNUM *a, int words)\n{\n    return (words <= a->dmax) ? a : bn_expand2(a, words);\n}', 'BIGNUM *bn_expand2(BIGNUM *b, int words)\n{\n    if (words > b->dmax) {\n        BN_ULONG *a = bn_expand_internal(b, words);\n        if (!a)\n            return NULL;\n        if (b->d) {\n            OPENSSL_cleanse(b->d, b->dmax * sizeof(b->d[0]));\n            bn_free_d(b);\n        }\n        b->d = a;\n        b->dmax = words;\n    }\n    return b;\n}', 'static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words)\n{\n    BN_ULONG *a = NULL;\n    if (words > (INT_MAX / (4 * BN_BITS2))) {\n        BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_BIGNUM_TOO_LONG);\n        return NULL;\n    }\n    if (BN_get_flags(b, BN_FLG_STATIC_DATA)) {\n        BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);\n        return NULL;\n    }\n    if (BN_get_flags(b, BN_FLG_SECURE))\n        a = OPENSSL_secure_zalloc(words * sizeof(*a));\n    else\n        a = OPENSSL_zalloc(words * sizeof(*a));\n    if (a == NULL) {\n        BNerr(BN_F_BN_EXPAND_INTERNAL, ERR_R_MALLOC_FAILURE);\n        return NULL;\n    }\n    assert(b->top <= words);\n    if (b->top > 0)\n        memcpy(a, b->d, sizeof(*a) * b->top);\n    return a;\n}']