Openssl 1.1.0h

2018-04-02 22:33:38 +09:00
commit 1fd4faa81c
2471 changed files with 719220 additions and 0 deletions
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+/*
+ * 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
+ */
+
+#include <assert.h>
+#include <limits.h>
+#include "internal/cryptlib.h"
+#include "bn_lcl.h"
+#include <openssl/opensslconf.h>
+
+/* This stuff appears to be completely unused, so is deprecated */
+#if OPENSSL_API_COMPAT < 0x00908000L
+/*-
+ * For a 32 bit machine
+ * 2 -   4 ==  128
+ * 3 -   8 ==  256
+ * 4 -  16 ==  512
+ * 5 -  32 == 1024
+ * 6 -  64 == 2048
+ * 7 - 128 == 4096
+ * 8 - 256 == 8192
+ */
+static int bn_limit_bits = 0;
+static int bn_limit_num = 8;    /* (1<<bn_limit_bits) */
+static int bn_limit_bits_low = 0;
+static int bn_limit_num_low = 8; /* (1<<bn_limit_bits_low) */
+static int bn_limit_bits_high = 0;
+static int bn_limit_num_high = 8; /* (1<<bn_limit_bits_high) */
+static int bn_limit_bits_mont = 0;
+static int bn_limit_num_mont = 8; /* (1<<bn_limit_bits_mont) */
+
+void BN_set_params(int mult, int high, int low, int mont)
+{
+    if (mult >= 0) {
+        if (mult > (int)(sizeof(int) * 8) - 1)
+            mult = sizeof(int) * 8 - 1;
+        bn_limit_bits = mult;
+        bn_limit_num = 1 << mult;
+    }
+    if (high >= 0) {
+        if (high > (int)(sizeof(int) * 8) - 1)
+            high = sizeof(int) * 8 - 1;
+        bn_limit_bits_high = high;
+        bn_limit_num_high = 1 << high;
+    }
+    if (low >= 0) {
+        if (low > (int)(sizeof(int) * 8) - 1)
+            low = sizeof(int) * 8 - 1;
+        bn_limit_bits_low = low;
+        bn_limit_num_low = 1 << low;
+    }
+    if (mont >= 0) {
+        if (mont > (int)(sizeof(int) * 8) - 1)
+            mont = sizeof(int) * 8 - 1;
+        bn_limit_bits_mont = mont;
+        bn_limit_num_mont = 1 << mont;
+    }
+}
+
+int BN_get_params(int which)
+{
+    if (which == 0)
+        return (bn_limit_bits);
+    else if (which == 1)
+        return (bn_limit_bits_high);
+    else if (which == 2)
+        return (bn_limit_bits_low);
+    else if (which == 3)
+        return (bn_limit_bits_mont);
+    else
+        return (0);
+}
+#endif
+
+const BIGNUM *BN_value_one(void)
+{
+    static const BN_ULONG data_one = 1L;
+    static const BIGNUM const_one =
+        { (BN_ULONG *)&data_one, 1, 1, 0, BN_FLG_STATIC_DATA };
+
+    return (&const_one);
+}
+
+int BN_num_bits_word(BN_ULONG l)
+{
+    BN_ULONG x, mask;
+    int bits = (l != 0);
+
+#if BN_BITS2 > 32
+    x = l >> 32;
+    mask = (0 - x) & BN_MASK2;
+    mask = (0 - (mask >> (BN_BITS2 - 1)));
+    bits += 32 & mask;
+    l ^= (x ^ l) & mask;
+#endif
+
+    x = l >> 16;
+    mask = (0 - x) & BN_MASK2;
+    mask = (0 - (mask >> (BN_BITS2 - 1)));
+    bits += 16 & mask;
+    l ^= (x ^ l) & mask;
+
+    x = l >> 8;
+    mask = (0 - x) & BN_MASK2;
+    mask = (0 - (mask >> (BN_BITS2 - 1)));
+    bits += 8 & mask;
+    l ^= (x ^ l) & mask;
+
+    x = l >> 4;
+    mask = (0 - x) & BN_MASK2;
+    mask = (0 - (mask >> (BN_BITS2 - 1)));
+    bits += 4 & mask;
+    l ^= (x ^ l) & mask;
+
+    x = l >> 2;
+    mask = (0 - x) & BN_MASK2;
+    mask = (0 - (mask >> (BN_BITS2 - 1)));
+    bits += 2 & mask;
+    l ^= (x ^ l) & mask;
+
+    x = l >> 1;
+    mask = (0 - x) & BN_MASK2;
+    mask = (0 - (mask >> (BN_BITS2 - 1)));
+    bits += 1 & mask;
+
+    return bits;
+}
+
+int BN_num_bits(const BIGNUM *a)
+{
+    int i = a->top - 1;
+    bn_check_top(a);
+
+    if (BN_is_zero(a))
+        return 0;
+    return ((i * BN_BITS2) + BN_num_bits_word(a->d[i]));
+}
+
+static void bn_free_d(BIGNUM *a)
+{
+    if (BN_get_flags(a, BN_FLG_SECURE))
+        OPENSSL_secure_free(a->d);
+    else
+        OPENSSL_free(a->d);
+}
+
+
+void BN_clear_free(BIGNUM *a)
+{
+    int i;
+
+    if (a == NULL)
+        return;
+    bn_check_top(a);
+    if (a->d != NULL) {
+        OPENSSL_cleanse(a->d, a->dmax * sizeof(a->d[0]));
+        if (!BN_get_flags(a, BN_FLG_STATIC_DATA))
+            bn_free_d(a);
+    }
+    i = BN_get_flags(a, BN_FLG_MALLOCED);
+    OPENSSL_cleanse(a, sizeof(*a));
+    if (i)
+        OPENSSL_free(a);
+}
+
+void BN_free(BIGNUM *a)
+{
+    if (a == NULL)
+        return;
+    bn_check_top(a);
+    if (!BN_get_flags(a, BN_FLG_STATIC_DATA))
+        bn_free_d(a);
+    if (a->flags & BN_FLG_MALLOCED)
+        OPENSSL_free(a);
+    else {
+#if OPENSSL_API_COMPAT < 0x00908000L
+        a->flags |= BN_FLG_FREE;
+#endif
+        a->d = NULL;
+    }
+}
+
+void bn_init(BIGNUM *a)
+{
+    static BIGNUM nilbn;
+
+    *a = nilbn;
+    bn_check_top(a);
+}
+
+BIGNUM *BN_new(void)
+{
+    BIGNUM *ret;
+
+    if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
+        BNerr(BN_F_BN_NEW, ERR_R_MALLOC_FAILURE);
+        return (NULL);
+    }
+    ret->flags = BN_FLG_MALLOCED;
+    bn_check_top(ret);
+    return (ret);
+}
+
+ BIGNUM *BN_secure_new(void)
+ {
+     BIGNUM *ret = BN_new();
+     if (ret != NULL)
+         ret->flags |= BN_FLG_SECURE;
+     return (ret);
+ }
+
+/* This is used by bn_expand2() */
+/* The caller MUST check that words > b->dmax before calling this */
+static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words)
+{
+    BN_ULONG *A, *a = NULL;
+    const BN_ULONG *B;
+    int i;
+
+    bn_check_top(b);
+
+    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 = A = OPENSSL_secure_zalloc(words * sizeof(*a));
+    else
+        a = A = OPENSSL_zalloc(words * sizeof(*a));
+    if (A == NULL) {
+        BNerr(BN_F_BN_EXPAND_INTERNAL, ERR_R_MALLOC_FAILURE);
+        return (NULL);
+    }
+
+#if 1
+    B = b->d;
+    /* Check if the previous number needs to be copied */
+    if (B != NULL) {
+        for (i = b->top >> 2; i > 0; i--, A += 4, B += 4) {
+            /*
+             * The fact that the loop is unrolled
+             * 4-wise is a tribute to Intel. It's
+             * the one that doesn't have enough
+             * registers to accommodate more data.
+             * I'd unroll it 8-wise otherwise:-)
+             *
+             *              <appro@fy.chalmers.se>
+             */
+            BN_ULONG a0, a1, a2, a3;
+            a0 = B[0];
+            a1 = B[1];
+            a2 = B[2];
+            a3 = B[3];
+            A[0] = a0;
+            A[1] = a1;
+            A[2] = a2;
+            A[3] = a3;
+        }
+        switch (b->top & 3) {
+        case 3:
+            A[2] = B[2];
+            /* fall thru */
+        case 2:
+            A[1] = B[1];
+            /* fall thru */
+        case 1:
+            A[0] = B[0];
+            /* fall thru */
+        case 0:
+            /* Without the "case 0" some old optimizers got this wrong. */
+            ;
+        }
+    }
+#else
+    memset(A, 0, sizeof(*A) * words);
+    memcpy(A, b->d, sizeof(b->d[0]) * b->top);
+#endif
+
+    return (a);
+}
+
+/*
+ * This is an internal function that should not be used in applications. It
+ * ensures that 'b' has enough room for a 'words' word number and initialises
+ * any unused part of b->d with leading zeros. It is mostly used by the
+ * various BIGNUM routines. If there is an error, NULL is returned. If not,
+ * 'b' is returned.
+ */
+
+BIGNUM *bn_expand2(BIGNUM *b, int words)
+{
+    bn_check_top(b);
+
+    if (words > b->dmax) {
+        BN_ULONG *a = bn_expand_internal(b, words);
+        if (!a)
+            return NULL;
+        if (b->d) {
+            OPENSSL_cleanse(b->d, b->dmax * sizeof(b->d[0]));
+            bn_free_d(b);
+        }
+        b->d = a;
+        b->dmax = words;
+    }
+
+    bn_check_top(b);
+    return b;
+}
+
+BIGNUM *BN_dup(const BIGNUM *a)
+{
+    BIGNUM *t;
+
+    if (a == NULL)
+        return NULL;
+    bn_check_top(a);
+
+    t = BN_get_flags(a, BN_FLG_SECURE) ? BN_secure_new() : BN_new();
+    if (t == NULL)
+        return NULL;
+    if (!BN_copy(t, a)) {
+        BN_free(t);
+        return NULL;
+    }
+    bn_check_top(t);
+    return t;
+}
+
+BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
+{
+    int i;
+    BN_ULONG *A;
+    const BN_ULONG *B;
+
+    bn_check_top(b);
+
+    if (a == b)
+        return (a);
+    if (bn_wexpand(a, b->top) == NULL)
+        return (NULL);
+
+#if 1
+    A = a->d;
+    B = b->d;
+    for (i = b->top >> 2; i > 0; i--, A += 4, B += 4) {
+        BN_ULONG a0, a1, a2, a3;
+        a0 = B[0];
+        a1 = B[1];
+        a2 = B[2];
+        a3 = B[3];
+        A[0] = a0;
+        A[1] = a1;
+        A[2] = a2;
+        A[3] = a3;
+    }
+    /* ultrix cc workaround, see comments in bn_expand_internal */
+    switch (b->top & 3) {
+    case 3:
+        A[2] = B[2];
+        /* fall thru */
+    case 2:
+        A[1] = B[1];
+        /* fall thru */
+    case 1:
+        A[0] = B[0];
+        /* fall thru */
+    case 0:;
+    }
+#else
+    memcpy(a->d, b->d, sizeof(b->d[0]) * b->top);
+#endif
+
+    a->top = b->top;
+    a->neg = b->neg;
+    bn_check_top(a);
+    return (a);
+}
+
+void BN_swap(BIGNUM *a, BIGNUM *b)
+{
+    int flags_old_a, flags_old_b;
+    BN_ULONG *tmp_d;
+    int tmp_top, tmp_dmax, tmp_neg;
+
+    bn_check_top(a);
+    bn_check_top(b);
+
+    flags_old_a = a->flags;
+    flags_old_b = b->flags;
+
+    tmp_d = a->d;
+    tmp_top = a->top;
+    tmp_dmax = a->dmax;
+    tmp_neg = a->neg;
+
+    a->d = b->d;
+    a->top = b->top;
+    a->dmax = b->dmax;
+    a->neg = b->neg;
+
+    b->d = tmp_d;
+    b->top = tmp_top;
+    b->dmax = tmp_dmax;
+    b->neg = tmp_neg;
+
+    a->flags =
+        (flags_old_a & BN_FLG_MALLOCED) | (flags_old_b & BN_FLG_STATIC_DATA);
+    b->flags =
+        (flags_old_b & BN_FLG_MALLOCED) | (flags_old_a & BN_FLG_STATIC_DATA);
+    bn_check_top(a);
+    bn_check_top(b);
+}
+
+void BN_clear(BIGNUM *a)
+{
+    bn_check_top(a);
+    if (a->d != NULL)
+        OPENSSL_cleanse(a->d, sizeof(*a->d) * a->dmax);
+    a->top = 0;
+    a->neg = 0;
+}
+
+BN_ULONG BN_get_word(const BIGNUM *a)
+{
+    if (a->top > 1)
+        return BN_MASK2;
+    else if (a->top == 1)
+        return a->d[0];
+    /* a->top == 0 */
+    return 0;
+}
+
+int BN_set_word(BIGNUM *a, BN_ULONG w)
+{
+    bn_check_top(a);
+    if (bn_expand(a, (int)sizeof(BN_ULONG) * 8) == NULL)
+        return (0);
+    a->neg = 0;
+    a->d[0] = w;
+    a->top = (w ? 1 : 0);
+    bn_check_top(a);
+    return (1);
+}
+
+BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
+{
+    unsigned int i, m;
+    unsigned int n;
+    BN_ULONG l;
+    BIGNUM *bn = NULL;
+
+    if (ret == NULL)
+        ret = bn = BN_new();
+    if (ret == NULL)
+        return (NULL);
+    bn_check_top(ret);
+    /* Skip leading zero's. */
+    for ( ; len > 0 && *s == 0; s++, len--)
+        continue;
+    n = len;
+    if (n == 0) {
+        ret->top = 0;
+        return (ret);
+    }
+    i = ((n - 1) / BN_BYTES) + 1;
+    m = ((n - 1) % (BN_BYTES));
+    if (bn_wexpand(ret, (int)i) == NULL) {
+        BN_free(bn);
+        return NULL;
+    }
+    ret->top = i;
+    ret->neg = 0;
+    l = 0;
+    while (n--) {
+        l = (l << 8L) | *(s++);
+        if (m-- == 0) {
+            ret->d[--i] = l;
+            l = 0;
+            m = BN_BYTES - 1;
+        }
+    }
+    /*
+     * need to call this due to clear byte at top if avoiding having the top
+     * bit set (-ve number)
+     */
+    bn_correct_top(ret);
+    return (ret);
+}
+
+/* ignore negative */
+static int bn2binpad(const BIGNUM *a, unsigned char *to, int tolen)
+{
+    int i;
+    BN_ULONG l;
+
+    bn_check_top(a);
+    i = BN_num_bytes(a);
+    if (tolen == -1)
+        tolen = i;
+    else if (tolen < i)
+        return -1;
+    /* Add leading zeroes if necessary */
+    if (tolen > i) {
+        memset(to, 0, tolen - i);
+        to += tolen - i;
+    }
+    while (i--) {
+        l = a->d[i / BN_BYTES];
+        *(to++) = (unsigned char)(l >> (8 * (i % BN_BYTES))) & 0xff;
+    }
+    return tolen;
+}
+
+int BN_bn2binpad(const BIGNUM *a, unsigned char *to, int tolen)
+{
+    if (tolen < 0)
+        return -1;
+    return bn2binpad(a, to, tolen);
+}
+
+int BN_bn2bin(const BIGNUM *a, unsigned char *to)
+{
+    return bn2binpad(a, to, -1);
+}
+
+BIGNUM *BN_lebin2bn(const unsigned char *s, int len, BIGNUM *ret)
+{
+    unsigned int i, m;
+    unsigned int n;
+    BN_ULONG l;
+    BIGNUM *bn = NULL;
+
+    if (ret == NULL)
+        ret = bn = BN_new();
+    if (ret == NULL)
+        return (NULL);
+    bn_check_top(ret);
+    s += len;
+    /* Skip trailing zeroes. */
+    for ( ; len > 0 && s[-1] == 0; s--, len--)
+        continue;
+    n = len;
+    if (n == 0) {
+        ret->top = 0;
+        return ret;
+    }
+    i = ((n - 1) / BN_BYTES) + 1;
+    m = ((n - 1) % (BN_BYTES));
+    if (bn_wexpand(ret, (int)i) == NULL) {
+        BN_free(bn);
+        return NULL;
+    }
+    ret->top = i;
+    ret->neg = 0;
+    l = 0;
+    while (n--) {
+        s--;
+        l = (l << 8L) | *s;
+        if (m-- == 0) {
+            ret->d[--i] = l;
+            l = 0;
+            m = BN_BYTES - 1;
+        }
+    }
+    /*
+     * need to call this due to clear byte at top if avoiding having the top
+     * bit set (-ve number)
+     */
+    bn_correct_top(ret);
+    return ret;
+}
+
+int BN_bn2lebinpad(const BIGNUM *a, unsigned char *to, int tolen)
+{
+    int i;
+    BN_ULONG l;
+    bn_check_top(a);
+    i = BN_num_bytes(a);
+    if (tolen < i)
+        return -1;
+    /* Add trailing zeroes if necessary */
+    if (tolen > i)
+        memset(to + i, 0, tolen - i);
+    to += i;
+    while (i--) {
+        l = a->d[i / BN_BYTES];
+        to--;
+        *to = (unsigned char)(l >> (8 * (i % BN_BYTES))) & 0xff;
+    }
+    return tolen;
+}
+
+int BN_ucmp(const BIGNUM *a, const BIGNUM *b)
+{
+    int i;
+    BN_ULONG t1, t2, *ap, *bp;
+
+    bn_check_top(a);
+    bn_check_top(b);
+
+    i = a->top - b->top;
+    if (i != 0)
+        return (i);
+    ap = a->d;
+    bp = b->d;
+    for (i = a->top - 1; i >= 0; i--) {
+        t1 = ap[i];
+        t2 = bp[i];
+        if (t1 != t2)
+            return ((t1 > t2) ? 1 : -1);
+    }
+    return (0);
+}
+
+int BN_cmp(const BIGNUM *a, const BIGNUM *b)
+{
+    int i;
+    int gt, lt;
+    BN_ULONG t1, t2;
+
+    if ((a == NULL) || (b == NULL)) {
+        if (a != NULL)
+            return (-1);
+        else if (b != NULL)
+            return (1);
+        else
+            return (0);
+    }
+
+    bn_check_top(a);
+    bn_check_top(b);
+
+    if (a->neg != b->neg) {
+        if (a->neg)
+            return (-1);
+        else
+            return (1);
+    }
+    if (a->neg == 0) {
+        gt = 1;
+        lt = -1;
+    } else {
+        gt = -1;
+        lt = 1;
+    }
+
+    if (a->top > b->top)
+        return (gt);
+    if (a->top < b->top)
+        return (lt);
+    for (i = a->top - 1; i >= 0; i--) {
+        t1 = a->d[i];
+        t2 = b->d[i];
+        if (t1 > t2)
+            return (gt);
+        if (t1 < t2)
+            return (lt);
+    }
+    return (0);
+}
+
+int BN_set_bit(BIGNUM *a, int n)
+{
+    int i, j, k;
+
+    if (n < 0)
+        return 0;
+
+    i = n / BN_BITS2;
+    j = n % BN_BITS2;
+    if (a->top <= i) {
+        if (bn_wexpand(a, i + 1) == NULL)
+            return (0);
+        for (k = a->top; k < i + 1; k++)
+            a->d[k] = 0;
+        a->top = i + 1;
+    }
+
+    a->d[i] |= (((BN_ULONG)1) << j);
+    bn_check_top(a);
+    return (1);
+}
+
+int BN_clear_bit(BIGNUM *a, int n)
+{
+    int i, j;
+
+    bn_check_top(a);
+    if (n < 0)
+        return 0;
+
+    i = n / BN_BITS2;
+    j = n % BN_BITS2;
+    if (a->top <= i)
+        return (0);
+
+    a->d[i] &= (~(((BN_ULONG)1) << j));
+    bn_correct_top(a);
+    return (1);
+}
+
+int BN_is_bit_set(const BIGNUM *a, int n)
+{
+    int i, j;
+
+    bn_check_top(a);
+    if (n < 0)
+        return 0;
+    i = n / BN_BITS2;
+    j = n % BN_BITS2;
+    if (a->top <= i)
+        return 0;
+    return (int)(((a->d[i]) >> j) & ((BN_ULONG)1));
+}
+
+int BN_mask_bits(BIGNUM *a, int n)
+{
+    int b, w;
+
+    bn_check_top(a);
+    if (n < 0)
+        return 0;
+
+    w = n / BN_BITS2;
+    b = n % BN_BITS2;
+    if (w >= a->top)
+        return 0;
+    if (b == 0)
+        a->top = w;
+    else {
+        a->top = w + 1;
+        a->d[w] &= ~(BN_MASK2 << b);
+    }
+    bn_correct_top(a);
+    return (1);
+}
+
+void BN_set_negative(BIGNUM *a, int b)
+{
+    if (b && !BN_is_zero(a))
+        a->neg = 1;
+    else
+        a->neg = 0;
+}
+
+int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n)
+{
+    int i;
+    BN_ULONG aa, bb;
+
+    aa = a[n - 1];
+    bb = b[n - 1];
+    if (aa != bb)
+        return ((aa > bb) ? 1 : -1);
+    for (i = n - 2; i >= 0; i--) {
+        aa = a[i];
+        bb = b[i];
+        if (aa != bb)
+            return ((aa > bb) ? 1 : -1);
+    }
+    return (0);
+}
+
+/*
+ * Here follows a specialised variants of bn_cmp_words().  It has the
+ * capability of performing the operation on arrays of different sizes. The
+ * sizes of those arrays is expressed through cl, which is the common length
+ * ( basically, min(len(a),len(b)) ), and dl, which is the delta between the
+ * two lengths, calculated as len(a)-len(b). All lengths are the number of
+ * BN_ULONGs...
+ */
+
+int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b, int cl, int dl)
+{
+    int n, i;
+    n = cl - 1;
+
+    if (dl < 0) {
+        for (i = dl; i < 0; i++) {
+            if (b[n - i] != 0)
+                return -1;      /* a < b */
+        }
+    }
+    if (dl > 0) {
+        for (i = dl; i > 0; i--) {
+            if (a[n + i] != 0)
+                return 1;       /* a > b */
+        }
+    }
+    return bn_cmp_words(a, b, cl);
+}
+
+/*
+ * Constant-time conditional swap of a and b.
+ * a and b are swapped if condition is not 0.  The code assumes that at most one bit of condition is set.
+ * nwords is the number of words to swap.  The code assumes that at least nwords are allocated in both a and b,
+ * and that no more than nwords are used by either a or b.
+ * a and b cannot be the same number
+ */
+void BN_consttime_swap(BN_ULONG condition, BIGNUM *a, BIGNUM *b, int nwords)
+{
+    BN_ULONG t;
+    int i;
+
+    bn_wcheck_size(a, nwords);
+    bn_wcheck_size(b, nwords);
+
+    assert(a != b);
+    assert((condition & (condition - 1)) == 0);
+    assert(sizeof(BN_ULONG) >= sizeof(int));
+
+    condition = ((condition - 1) >> (BN_BITS2 - 1)) - 1;
+
+    t = (a->top ^ b->top) & condition;
+    a->top ^= t;
+    b->top ^= t;
+
+#define BN_CONSTTIME_SWAP(ind) \
+        do { \
+                t = (a->d[ind] ^ b->d[ind]) & condition; \
+                a->d[ind] ^= t; \
+                b->d[ind] ^= t; \
+        } while (0)
+
+    switch (nwords) {
+    default:
+        for (i = 10; i < nwords; i++)
+            BN_CONSTTIME_SWAP(i);
+        /* Fallthrough */
+    case 10:
+        BN_CONSTTIME_SWAP(9);   /* Fallthrough */
+    case 9:
+        BN_CONSTTIME_SWAP(8);   /* Fallthrough */
+    case 8:
+        BN_CONSTTIME_SWAP(7);   /* Fallthrough */
+    case 7:
+        BN_CONSTTIME_SWAP(6);   /* Fallthrough */
+    case 6:
+        BN_CONSTTIME_SWAP(5);   /* Fallthrough */
+    case 5:
+        BN_CONSTTIME_SWAP(4);   /* Fallthrough */
+    case 4:
+        BN_CONSTTIME_SWAP(3);   /* Fallthrough */
+    case 3:
+        BN_CONSTTIME_SWAP(2);   /* Fallthrough */
+    case 2:
+        BN_CONSTTIME_SWAP(1);   /* Fallthrough */
+    case 1:
+        BN_CONSTTIME_SWAP(0);
+    }
+#undef BN_CONSTTIME_SWAP
+}
+
+/* Bits of security, see SP800-57 */
+
+int BN_security_bits(int L, int N)
+{
+    int secbits, bits;
+    if (L >= 15360)
+        secbits = 256;
+    else if (L >= 7680)
+        secbits = 192;
+    else if (L >= 3072)
+        secbits = 128;
+    else if (L >= 2048)
+        secbits = 112;
+    else if (L >= 1024)
+        secbits = 80;
+    else
+        return 0;
+    if (N == -1)
+        return secbits;
+    bits = N / 2;
+    if (bits < 80)
+        return 0;
+    return bits >= secbits ? secbits : bits;
+}
+
+void BN_zero_ex(BIGNUM *a)
+{
+    a->top = 0;
+    a->neg = 0;
+}
+
+int BN_abs_is_word(const BIGNUM *a, const BN_ULONG w)
+{
+    return ((a->top == 1) && (a->d[0] == w)) || ((w == 0) && (a->top == 0));
+}
+
+int BN_is_zero(const BIGNUM *a)
+{
+    return a->top == 0;
+}
+
+int BN_is_one(const BIGNUM *a)
+{
+    return BN_abs_is_word(a, 1) && !a->neg;
+}
+
+int BN_is_word(const BIGNUM *a, const BN_ULONG w)
+{
+    return BN_abs_is_word(a, w) && (!w || !a->neg);
+}
+
+int BN_is_odd(const BIGNUM *a)
+{
+    return (a->top > 0) && (a->d[0] & 1);
+}
+
+int BN_is_negative(const BIGNUM *a)
+{
+    return (a->neg != 0);
+}
+
+int BN_to_montgomery(BIGNUM *r, const BIGNUM *a, BN_MONT_CTX *mont,
+                     BN_CTX *ctx)
+{
+    return BN_mod_mul_montgomery(r, a, &(mont->RR), mont, ctx);
+}
+
+void BN_with_flags(BIGNUM *dest, const BIGNUM *b, int flags)
+{
+    dest->d = b->d;
+    dest->top = b->top;
+    dest->dmax = b->dmax;
+    dest->neg = b->neg;
+    dest->flags = ((dest->flags & BN_FLG_MALLOCED)
+                   | (b->flags & ~BN_FLG_MALLOCED)
+                   | BN_FLG_STATIC_DATA | flags);
+}
+
+BN_GENCB *BN_GENCB_new(void)
+{
+    BN_GENCB *ret;
+
+    if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL) {
+        BNerr(BN_F_BN_GENCB_NEW, ERR_R_MALLOC_FAILURE);
+        return (NULL);
+    }
+
+    return ret;
+}
+
+void BN_GENCB_free(BN_GENCB *cb)
+{
+    if (cb == NULL)
+        return;
+    OPENSSL_free(cb);
+}
+
+void BN_set_flags(BIGNUM *b, int n)
+{
+    b->flags |= n;
+}
+
+int BN_get_flags(const BIGNUM *b, int n)
+{
+    return b->flags & n;
+}
+
+/* Populate a BN_GENCB structure with an "old"-style callback */
+void BN_GENCB_set_old(BN_GENCB *gencb, void (*callback) (int, int, void *),
+                      void *cb_arg)
+{
+    BN_GENCB *tmp_gencb = gencb;
+    tmp_gencb->ver = 1;
+    tmp_gencb->arg = cb_arg;
+    tmp_gencb->cb.cb_1 = callback;
+}
+
+/* Populate a BN_GENCB structure with a "new"-style callback */
+void BN_GENCB_set(BN_GENCB *gencb, int (*callback) (int, int, BN_GENCB *),
+                  void *cb_arg)
+{
+    BN_GENCB *tmp_gencb = gencb;
+    tmp_gencb->ver = 2;
+    tmp_gencb->arg = cb_arg;
+    tmp_gencb->cb.cb_2 = callback;
+}
+
+void *BN_GENCB_get_arg(BN_GENCB *cb)
+{
+    return cb->arg;
+}
+
+BIGNUM *bn_wexpand(BIGNUM *a, int words)
+{
+    return (words <= a->dmax) ? a : bn_expand2(a, words);
+}
+
+void bn_correct_top(BIGNUM *a)
+{
+    BN_ULONG *ftl;
+    int tmp_top = a->top;
+
+    if (tmp_top > 0) {
+        for (ftl = &(a->d[tmp_top]); tmp_top > 0; tmp_top--) {
+            ftl--;
+            if (*ftl != 0)
+                break;
+        }
+        a->top = tmp_top;
+    }
+    if (a->top == 0)
+        a->neg = 0;
+    bn_pollute(a);
+}