/*
- * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
+ * 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
#include "internal/cryptlib.h"
#include "bn_lcl.h"
#include <openssl/opensslconf.h>
+#include "internal/constant_time_locl.h"
/* This stuff appears to be completely unused, so is deprecated */
#if OPENSSL_API_COMPAT < 0x00908000L
int BN_get_params(int which)
{
if (which == 0)
- return (bn_limit_bits);
+ return bn_limit_bits;
else if (which == 1)
- return (bn_limit_bits_high);
+ return bn_limit_bits_high;
else if (which == 2)
- return (bn_limit_bits_low);
+ return bn_limit_bits_low;
else if (which == 3)
- return (bn_limit_bits_mont);
+ return bn_limit_bits_mont;
else
- return (0);
+ return 0;
}
#endif
static const BIGNUM const_one =
{ (BN_ULONG *)&data_one, 1, 1, 0, BN_FLG_STATIC_DATA };
- return (&const_one);
+ return &const_one;
}
int BN_num_bits_word(BN_ULONG l)
{
- static const unsigned char bits[256] = {
- 0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4,
- 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
- 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
- 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
- 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
- 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
- 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
- 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
- 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
- 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
- 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
- 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
- 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
- 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
- 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
- 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
- };
-
-#if defined(SIXTY_FOUR_BIT_LONG)
- if (l & 0xffffffff00000000L) {
- if (l & 0xffff000000000000L) {
- if (l & 0xff00000000000000L) {
- return (bits[(int)(l >> 56)] + 56);
- } else
- return (bits[(int)(l >> 48)] + 48);
- } else {
- if (l & 0x0000ff0000000000L) {
- return (bits[(int)(l >> 40)] + 40);
- } else
- return (bits[(int)(l >> 32)] + 32);
- }
- } else
-#else
-# ifdef SIXTY_FOUR_BIT
- if (l & 0xffffffff00000000LL) {
- if (l & 0xffff000000000000LL) {
- if (l & 0xff00000000000000LL) {
- return (bits[(int)(l >> 56)] + 56);
- } else
- return (bits[(int)(l >> 48)] + 48);
- } else {
- if (l & 0x0000ff0000000000LL) {
- return (bits[(int)(l >> 40)] + 40);
- } else
- return (bits[(int)(l >> 32)] + 32);
- }
- } else
-# endif
-#endif
- {
-#if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
- if (l & 0xffff0000L) {
- if (l & 0xff000000L)
- return (bits[(int)(l >> 24L)] + 24);
- else
- return (bits[(int)(l >> 16L)] + 16);
- } else
-#endif
- {
-#if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
- if (l & 0xff00L)
- return (bits[(int)(l >> 8)] + 8);
- else
+ 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
- return (bits[(int)(l)]);
- }
- }
+
+ 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)
if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
BNerr(BN_F_BN_NEW, ERR_R_MALLOC_FAILURE);
- return (NULL);
+ return NULL;
}
ret->flags = BN_FLG_MALLOCED;
bn_check_top(ret);
- return (ret);
+ return ret;
}
BIGNUM *BN_secure_new(void)
BIGNUM *ret = BN_new();
if (ret != NULL)
ret->flags |= BN_FLG_SECURE;
- return (ret);
+ return ret;
}
/* This is used by bn_expand2() */
{
BN_ULONG *a = NULL;
- 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);
+ return NULL;
}
if (BN_get_flags(b, BN_FLG_SECURE))
a = OPENSSL_secure_zalloc(words * sizeof(*a));
a = OPENSSL_zalloc(words * sizeof(*a));
if (a == NULL) {
BNerr(BN_F_BN_EXPAND_INTERNAL, ERR_R_MALLOC_FAILURE);
- return (NULL);
+ return NULL;
}
assert(b->top <= words);
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)
b->dmax = words;
}
- bn_check_top(b);
return b;
}
if (b->top > 0)
memcpy(a->d, b->d, sizeof(b->d[0]) * b->top);
- if (BN_get_flags(b, BN_FLG_CONSTTIME) != 0)
- BN_set_flags(a, BN_FLG_CONSTTIME);
-
- a->top = b->top;
a->neg = b->neg;
+ a->top = b->top;
+ a->flags |= b->flags & BN_FLG_FIXED_TOP;
bn_check_top(a);
return a;
}
+#define FLAGS_DATA(flags) ((flags) & (BN_FLG_STATIC_DATA \
+ | BN_FLG_CONSTTIME \
+ | BN_FLG_SECURE \
+ | BN_FLG_FIXED_TOP))
+#define FLAGS_STRUCT(flags) ((flags) & (BN_FLG_MALLOCED))
+
void BN_swap(BIGNUM *a, BIGNUM *b)
{
int flags_old_a, flags_old_b;
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);
+ a->flags = FLAGS_STRUCT(flags_old_a) | FLAGS_DATA(flags_old_b);
+ b->flags = FLAGS_STRUCT(flags_old_b) | FLAGS_DATA(flags_old_a);
bn_check_top(a);
bn_check_top(b);
}
bn_check_top(a);
if (a->d != NULL)
OPENSSL_cleanse(a->d, sizeof(*a->d) * a->dmax);
- a->top = 0;
a->neg = 0;
+ a->top = 0;
+ a->flags &= ~BN_FLG_FIXED_TOP;
}
BN_ULONG BN_get_word(const BIGNUM *a)
{
bn_check_top(a);
if (bn_expand(a, (int)sizeof(BN_ULONG) * 8) == NULL)
- return (0);
+ return 0;
a->neg = 0;
a->d[0] = w;
a->top = (w ? 1 : 0);
+ a->flags &= ~BN_FLG_FIXED_TOP;
bn_check_top(a);
return 1;
}
if (ret == NULL)
ret = bn = BN_new();
if (ret == NULL)
- return (NULL);
+ return NULL;
bn_check_top(ret);
/* Skip leading zero's. */
for ( ; len > 0 && *s == 0; s++, len--)
n = len;
if (n == 0) {
ret->top = 0;
- return (ret);
+ return ret;
}
i = ((n - 1) / BN_BYTES) + 1;
m = ((n - 1) % (BN_BYTES));
* bit set (-ve number)
*/
bn_correct_top(ret);
- return (ret);
+ return ret;
}
/* ignore negative */
static int bn2binpad(const BIGNUM *a, unsigned char *to, int tolen)
{
- int i;
+ int n;
+ size_t i, lasti, j, atop, mask;
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;
+ /*
+ * In case |a| is fixed-top, BN_num_bytes can return bogus length,
+ * but it's assumed that fixed-top inputs ought to be "nominated"
+ * even for padded output, so it works out...
+ */
+ n = BN_num_bytes(a);
+ if (tolen == -1) {
+ tolen = n;
+ } else if (tolen < n) { /* uncommon/unlike case */
+ BIGNUM temp = *a;
+
+ bn_correct_top(&temp);
+ n = BN_num_bytes(&temp);
+ if (tolen < n)
+ return -1;
}
- while (i--) {
+
+ /* Swipe through whole available data and don't give away padded zero. */
+ atop = a->dmax * BN_BYTES;
+ if (atop == 0) {
+ OPENSSL_cleanse(to, tolen);
+ return tolen;
+ }
+
+ lasti = atop - 1;
+ atop = a->top * BN_BYTES;
+ for (i = 0, j = 0, to += tolen; j < (size_t)tolen; j++) {
l = a->d[i / BN_BYTES];
- *(to++) = (unsigned char)(l >> (8 * (i % BN_BYTES))) & 0xff;
+ mask = 0 - ((j - atop) >> (8 * sizeof(i) - 1));
+ *--to = (unsigned char)(l >> (8 * (i % BN_BYTES)) & mask);
+ i += (i - lasti) >> (8 * sizeof(i) - 1); /* stay on last limb */
}
+
return tolen;
}
if (ret == NULL)
ret = bn = BN_new();
if (ret == NULL)
- return (NULL);
+ return NULL;
bn_check_top(ret);
s += len;
/* Skip trailing zeroes. */
i = a->top - b->top;
if (i != 0)
- return (i);
+ return i;
ap = a->d;
bp = b->d;
for (i = a->top - 1; i >= 0; i--) {
if (t1 != t2)
return ((t1 > t2) ? 1 : -1);
}
- return (0);
+ return 0;
}
int BN_cmp(const BIGNUM *a, const BIGNUM *b)
if ((a == NULL) || (b == NULL)) {
if (a != NULL)
- return (-1);
+ return -1;
else if (b != NULL)
return 1;
else
- return (0);
+ return 0;
}
bn_check_top(a);
if (a->neg != b->neg) {
if (a->neg)
- return (-1);
+ return -1;
else
return 1;
}
}
if (a->top > b->top)
- return (gt);
+ return gt;
if (a->top < b->top)
- return (lt);
+ return lt;
for (i = a->top - 1; i >= 0; i--) {
t1 = a->d[i];
t2 = b->d[i];
if (t1 > t2)
- return (gt);
+ return gt;
if (t1 < t2)
- return (lt);
+ return lt;
}
- return (0);
+ return 0;
}
int BN_set_bit(BIGNUM *a, int n)
j = n % BN_BITS2;
if (a->top <= i) {
if (bn_wexpand(a, i + 1) == NULL)
- return (0);
+ return 0;
for (k = a->top; k < i + 1; k++)
a->d[k] = 0;
a->top = i + 1;
+ a->flags &= ~BN_FLG_FIXED_TOP;
}
a->d[i] |= (((BN_ULONG)1) << j);
i = n / BN_BITS2;
j = n % BN_BITS2;
if (a->top <= i)
- return (0);
+ return 0;
a->d[i] &= (~(((BN_ULONG)1) << j));
bn_correct_top(a);
if (aa != bb)
return ((aa > bb) ? 1 : -1);
}
- return (0);
+ return 0;
}
/*
a->top ^= t;
b->top ^= t;
+ t = (a->neg ^ b->neg) & condition;
+ a->neg ^= t;
+ b->neg ^= t;
+
+ /*-
+ * BN_FLG_STATIC_DATA: indicates that data may not be written to. Intention
+ * is actually to treat it as it's read-only data, and some (if not most)
+ * of it does reside in read-only segment. In other words observation of
+ * BN_FLG_STATIC_DATA in BN_consttime_swap should be treated as fatal
+ * condition. It would either cause SEGV or effectively cause data
+ * corruption.
+ *
+ * BN_FLG_MALLOCED: refers to BN structure itself, and hence must be
+ * preserved.
+ *
+ * BN_FLG_SECURE: must be preserved, because it determines how x->d was
+ * allocated and hence how to free it.
+ *
+ * BN_FLG_CONSTTIME: sufficient to mask and swap
+ *
+ * BN_FLG_FIXED_TOP: indicates that we haven't called bn_correct_top() on
+ * the data, so the d array may be padded with additional 0 values (i.e.
+ * top could be greater than the minimal value that it could be). We should
+ * be swapping it
+ */
+
+#define BN_CONSTTIME_SWAP_FLAGS (BN_FLG_CONSTTIME | BN_FLG_FIXED_TOP)
+
+ t = ((a->flags ^ b->flags) & BN_CONSTTIME_SWAP_FLAGS) & condition;
+ a->flags ^= t;
+ b->flags ^= t;
+
#define BN_CONSTTIME_SWAP(ind) \
do { \
t = (a->d[ind] ^ b->d[ind]) & condition; \
int secbits, bits;
if (L >= 15360)
secbits = 256;
- else if (L >= 7690)
+ else if (L >= 7680)
secbits = 192;
else if (L >= 3072)
secbits = 128;
void BN_zero_ex(BIGNUM *a)
{
- a->top = 0;
a->neg = 0;
+ a->top = 0;
+ a->flags &= ~BN_FLG_FIXED_TOP;
}
int BN_abs_is_word(const BIGNUM *a, const BN_ULONG w)
if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL) {
BNerr(BN_F_BN_GENCB_NEW, ERR_R_MALLOC_FAILURE);
- return (NULL);
+ return NULL;
}
return ret;
}
if (a->top == 0)
a->neg = 0;
+ a->flags &= ~BN_FLG_FIXED_TOP;
bn_pollute(a);
}
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