diff options
Diffstat (limited to 'crypto/bn/bn_lib.c')
| -rw-r--r-- | crypto/bn/bn_lib.c | 729 |
1 files changed, 412 insertions, 317 deletions
diff --git a/crypto/bn/bn_lib.c b/crypto/bn/bn_lib.c index 27b9bdbc3c28..266a3dd3046b 100644 --- a/crypto/bn/bn_lib.c +++ b/crypto/bn/bn_lib.c @@ -1,76 +1,21 @@ -/* crypto/bn/bn_lib.c */ -/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) - * All rights reserved. - * - * This package is an SSL implementation written - * by Eric Young (eay@cryptsoft.com). - * The implementation was written so as to conform with Netscapes SSL. - * - * This library is free for commercial and non-commercial use as long as - * the following conditions are aheared to. The following conditions - * apply to all code found in this distribution, be it the RC4, RSA, - * lhash, DES, etc., code; not just the SSL code. The SSL documentation - * included with this distribution is covered by the same copyright terms - * except that the holder is Tim Hudson (tjh@cryptsoft.com). - * - * Copyright remains Eric Young's, and as such any Copyright notices in - * the code are not to be removed. - * If this package is used in a product, Eric Young should be given attribution - * as the author of the parts of the library used. - * This can be in the form of a textual message at program startup or - * in documentation (online or textual) provided with the package. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * 3. All advertising materials mentioning features or use of this software - * must display the following acknowledgement: - * "This product includes cryptographic software written by - * Eric Young (eay@cryptsoft.com)" - * The word 'cryptographic' can be left out if the rouines from the library - * being used are not cryptographic related :-). - * 4. If you include any Windows specific code (or a derivative thereof) from - * the apps directory (application code) you must include an acknowledgement: - * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" - * - * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND - * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE - * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL - * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS - * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY - * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF - * SUCH DAMAGE. +/* + * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved. * - * The licence and distribution terms for any publically available version or - * derivative of this code cannot be changed. i.e. this code cannot simply be - * copied and put under another distribution licence - * [including the GNU Public Licence.] + * 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 */ -#ifndef BN_DEBUG -# undef NDEBUG /* avoid conflicting definitions */ -# define NDEBUG -#endif - #include <assert.h> #include <limits.h> -#include <stdio.h> -#include "cryptlib.h" +#include "internal/cryptlib.h" #include "bn_lcl.h" - -const char BN_version[] = "Big Number" OPENSSL_VERSION_PTEXT; +#include <openssl/opensslconf.h> +#include "internal/constant_time_locl.h" /* This stuff appears to be completely unused, so is deprecated */ -#ifndef OPENSSL_NO_DEPRECATED +#if OPENSSL_API_COMPAT < 0x00908000L /*- * For a 32 bit machine * 2 - 4 == 128 @@ -121,15 +66,15 @@ void BN_set_params(int mult, int high, int low, int mont) 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 @@ -139,7 +84,7 @@ const BIGNUM *BN_value_one(void) 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) @@ -197,44 +142,44 @@ int BN_num_bits(const BIGNUM *a) return ((i * BN_BITS2) + BN_num_bits_word(a->d[i])); } -void BN_clear_free(BIGNUM *a) +static void bn_free_d(BIGNUM *a) { - int i; + if (BN_get_flags(a, BN_FLG_SECURE)) + OPENSSL_secure_free(a->d); + else + OPENSSL_free(a->d); +} + +void BN_clear_free(BIGNUM *a) +{ if (a == NULL) return; - bn_check_top(a); - if (a->d != NULL) { + if (a->d != NULL && !BN_get_flags(a, BN_FLG_STATIC_DATA)) { OPENSSL_cleanse(a->d, a->dmax * sizeof(a->d[0])); - if (!(BN_get_flags(a, BN_FLG_STATIC_DATA))) - OPENSSL_free(a->d); + bn_free_d(a); } - i = BN_get_flags(a, BN_FLG_MALLOCED); - OPENSSL_cleanse(a, sizeof(BIGNUM)); - if (i) + if (BN_get_flags(a, BN_FLG_MALLOCED)) { + OPENSSL_cleanse(a, sizeof(*a)); OPENSSL_free(a); + } } void BN_free(BIGNUM *a) { if (a == NULL) return; - bn_check_top(a); - if ((a->d != NULL) && !(BN_get_flags(a, BN_FLG_STATIC_DATA))) - OPENSSL_free(a->d); + if (!BN_get_flags(a, BN_FLG_STATIC_DATA)) + bn_free_d(a); if (a->flags & BN_FLG_MALLOCED) OPENSSL_free(a); - else { -#ifndef OPENSSL_NO_DEPRECATED - a->flags |= BN_FLG_FREE; -#endif - a->d = NULL; - } } -void BN_init(BIGNUM *a) +void bn_init(BIGNUM *a) { - memset(a, 0, sizeof(BIGNUM)); + static BIGNUM nilbn; + + *a = nilbn; bn_check_top(a); } @@ -242,28 +187,28 @@ BIGNUM *BN_new(void) { BIGNUM *ret; - if ((ret = (BIGNUM *)OPENSSL_malloc(sizeof(BIGNUM))) == NULL) { + 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; - ret->top = 0; - ret->neg = 0; - ret->dmax = 0; - ret->d = NULL; bn_check_top(ret); - return (ret); + return ret; } -/* This is used both by bn_expand2() and bn_dup_expand() */ + 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); + BN_ULONG *a = NULL; if (words > (INT_MAX / (4 * BN_BITS2))) { BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_BIGNUM_TOO_LONG); @@ -271,124 +216,25 @@ static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words) } 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; } - a = A = (BN_ULONG *)OPENSSL_malloc(sizeof(BN_ULONG) * words); - if (A == 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); + return NULL; } -#ifdef PURIFY - /* - * Valgrind complains in BN_consttime_swap because we process the whole - * array even if it's not initialised yet. This doesn't matter in that - * function - what's important is constant time operation (we're not - * actually going to use the data) - */ - memset(a, 0, sizeof(BN_ULONG) * words); -#endif -#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 accomodate 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; - } - /* - * workaround for ultrix cc: without 'case 0', the optimizer does - * the switch table by doing a=top&3; a--; goto jump_table[a]; - * which fails for top== 0 - */ - switch (b->top & 3) { - case 3: - A[2] = B[2]; - case 2: - A[1] = B[1]; - case 1: - A[0] = B[0]; - case 0: - ; - } - } -#else - memset(A, 0, sizeof(BN_ULONG) * words); - memcpy(A, b->d, sizeof(b->d[0]) * b->top); -#endif + assert(b->top <= words); + if (b->top > 0) + memcpy(a, b->d, sizeof(*a) * b->top); - return (a); + return a; } /* - * This is an internal function that can be used instead of bn_expand2() when - * there is a need to copy BIGNUMs instead of only expanding the data part, - * while still expanding them. Especially useful when needing to expand - * BIGNUMs that are declared 'const' and should therefore not be changed. The - * reason to use this instead of a BN_dup() followed by a bn_expand2() is - * memory allocation overhead. A BN_dup() followed by a bn_expand2() will - * allocate new memory for the BIGNUM data twice, and free it once, while - * bn_dup_expand() makes sure allocation is made only once. - */ - -#ifndef OPENSSL_NO_DEPRECATED -BIGNUM *bn_dup_expand(const BIGNUM *b, int words) -{ - BIGNUM *r = NULL; - - bn_check_top(b); - - /* - * This function does not work if words <= b->dmax && top < words because - * BN_dup() does not preserve 'dmax'! (But bn_dup_expand() is not used - * anywhere yet.) - */ - - if (words > b->dmax) { - BN_ULONG *a = bn_expand_internal(b, words); - - if (a) { - r = BN_new(); - if (r) { - r->top = b->top; - r->dmax = words; - r->neg = b->neg; - r->d = a; - } else { - /* r == NULL, BN_new failure */ - OPENSSL_free(a); - } - } - /* - * If a == NULL, there was an error in allocation in - * bn_expand_internal(), and NULL should be returned - */ - } else { - r = BN_dup(b); - } - - bn_check_top(r); - return r; -} -#endif - -/* * 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 @@ -398,42 +244,18 @@ BIGNUM *bn_dup_expand(const BIGNUM *b, int 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) return NULL; - if (b->d) - OPENSSL_free(b->d); + if (b->d) { + OPENSSL_cleanse(b->d, b->dmax * sizeof(b->d[0])); + bn_free_d(b); + } b->d = a; b->dmax = words; } -/* None of this should be necessary because of what b->top means! */ -#if 0 - /* - * NB: bn_wexpand() calls this only if the BIGNUM really has to grow - */ - if (b->top < b->dmax) { - int i; - BN_ULONG *A = &(b->d[b->top]); - for (i = (b->dmax - b->top) >> 3; i > 0; i--, A += 8) { - A[0] = 0; - A[1] = 0; - A[2] = 0; - A[3] = 0; - A[4] = 0; - A[5] = 0; - A[6] = 0; - A[7] = 0; - } - for (i = (b->dmax - b->top) & 7; i > 0; i--, A++) - A[0] = 0; - assert(A == &(b->d[b->dmax])); - } -#endif - bn_check_top(b); return b; } @@ -445,7 +267,7 @@ BIGNUM *BN_dup(const BIGNUM *a) return NULL; bn_check_top(a); - t = BN_new(); + t = BN_get_flags(a, BN_FLG_SECURE) ? BN_secure_new() : BN_new(); if (t == NULL) return NULL; if (!BN_copy(t, a)) { @@ -458,51 +280,29 @@ BIGNUM *BN_dup(const BIGNUM *a) 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); + 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]; - case 2: - A[1] = B[1]; - case 1: - A[0] = B[0]; - case 0:; - } -#else - memcpy(a->d, b->d, sizeof(b->d[0]) * b->top); -#endif + return NULL; + + if (b->top > 0) + memcpy(a->d, b->d, sizeof(b->d[0]) * b->top); - 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); + 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; @@ -530,10 +330,8 @@ void BN_swap(BIGNUM *a, BIGNUM *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); } @@ -542,9 +340,10 @@ void BN_clear(BIGNUM *a) { bn_check_top(a); if (a->d != NULL) - OPENSSL_cleanse(a->d, a->dmax * sizeof(a->d[0])); - a->top = 0; + OPENSSL_cleanse(a->d, sizeof(*a->d) * a->dmax); a->neg = 0; + a->top = 0; + a->flags &= ~BN_FLG_FIXED_TOP; } BN_ULONG BN_get_word(const BIGNUM *a) @@ -561,12 +360,13 @@ 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); + 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); + return 1; } BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret) @@ -579,23 +379,25 @@ BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret) if (ret == NULL) ret = bn = BN_new(); if (ret == NULL) - return (NULL); + return NULL; bn_check_top(ret); - l = 0; + /* Skip leading zero's. */ + for ( ; len > 0 && *s == 0; s++, len--) + continue; n = len; if (n == 0) { ret->top = 0; - return (ret); + return ret; } i = ((n - 1) / BN_BYTES) + 1; m = ((n - 1) % (BN_BYTES)); if (bn_wexpand(ret, (int)i) == NULL) { - if (bn) - BN_free(bn); + BN_free(bn); return NULL; } ret->top = i; ret->neg = 0; + l = 0; while (n--) { l = (l << 8L) | *(s++); if (m-- == 0) { @@ -609,22 +411,129 @@ BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret) * 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 n; + size_t i, lasti, j, atop, mask; + BN_ULONG l; + + /* + * 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; + } + + /* 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]; + 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; +} + +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) { - int n, i; + 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); - n = i = BN_num_bytes(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++) = (unsigned char)(l >> (8 * (i % BN_BYTES))) & 0xff; + to--; + *to = (unsigned char)(l >> (8 * (i % BN_BYTES))) & 0xff; } - return (n); + return tolen; } int BN_ucmp(const BIGNUM *a, const BIGNUM *b) @@ -637,7 +546,7 @@ int BN_ucmp(const BIGNUM *a, const BIGNUM *b) 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--) { @@ -646,7 +555,7 @@ int BN_ucmp(const BIGNUM *a, const BIGNUM *b) if (t1 != t2) return ((t1 > t2) ? 1 : -1); } - return (0); + return 0; } int BN_cmp(const BIGNUM *a, const BIGNUM *b) @@ -657,11 +566,11 @@ 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); + return 1; else - return (0); + return 0; } bn_check_top(a); @@ -669,9 +578,9 @@ int BN_cmp(const BIGNUM *a, const BIGNUM *b) if (a->neg != b->neg) { if (a->neg) - return (-1); + return -1; else - return (1); + return 1; } if (a->neg == 0) { gt = 1; @@ -682,18 +591,18 @@ int BN_cmp(const BIGNUM *a, const BIGNUM *b) } 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) @@ -707,15 +616,16 @@ 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); bn_check_top(a); - return (1); + return 1; } int BN_clear_bit(BIGNUM *a, int n) @@ -729,11 +639,11 @@ int BN_clear_bit(BIGNUM *a, int n) 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); - return (1); + return 1; } int BN_is_bit_set(const BIGNUM *a, int n) @@ -769,7 +679,7 @@ int BN_mask_bits(BIGNUM *a, int n) a->d[w] &= ~(BN_MASK2 << b); } bn_correct_top(a); - return (1); + return 1; } void BN_set_negative(BIGNUM *a, int b) @@ -795,14 +705,14 @@ int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n) if (aa != bb) return ((aa > bb) ? 1 : -1); } - return (0); + return 0; } /* * Here follows a specialised variants of bn_cmp_words(). It has the - * property of performing the operation on arrays of different sizes. 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 - * ( basicall, min(len(a),len(b)) ), and dl, which is the delta between the + * ( 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... */ @@ -852,6 +762,34 @@ void BN_consttime_swap(BN_ULONG condition, BIGNUM *a, BIGNUM *b, int nwords) a->top ^= t; b->top ^= t; + t = (a->neg ^ b->neg) & condition; + a->neg ^= t; + b->neg ^= t; + + /*- + * Idea behind BN_FLG_STATIC_DATA is actually to + * indicate 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. Remaining flags are + * BN_FLG_CONSTIME and BN_FLG_SECURE. Latter must be + * preserved, because it determines how x->d was + * allocated and hence how to free it. This leaves + * BN_FLG_CONSTTIME that one can do something about. + * To summarize it's sufficient to mask and swap + * BN_FLG_CONSTTIME alone. BN_FLG_STATIC_DATA should + * be treated as fatal. + */ + t = ((a->flags ^ b->flags) & BN_FLG_CONSTTIME) & condition; + a->flags ^= t; + b->flags ^= t; + #define BN_CONSTTIME_SWAP(ind) \ do { \ t = (a->d[ind] ^ b->d[ind]) & condition; \ @@ -887,3 +825,160 @@ void BN_consttime_swap(BN_ULONG condition, BIGNUM *a, BIGNUM *b, int nwords) } #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->neg = 0; + a->top = 0; + a->flags &= ~BN_FLG_FIXED_TOP; +} + +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; + a->flags &= ~BN_FLG_FIXED_TOP; + bn_pollute(a); +} |