mirror of
https://github.com/monero-project/monero.git
synced 2024-11-06 00:17:37 +00:00
113 lines
4.7 KiB
C
113 lines
4.7 KiB
C
// Copyright (c) 2014-2015, The Monero Project
|
|
//
|
|
// All rights reserved.
|
|
//
|
|
// 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 above 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. Neither the name of the copyright holder nor the names of its contributors may be
|
|
// used to endorse or promote products derived from this software without specific
|
|
// prior written permission.
|
|
//
|
|
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT HOLDER 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.
|
|
//
|
|
// Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers
|
|
|
|
#include <assert.h>
|
|
#include <stddef.h>
|
|
#include <string.h>
|
|
|
|
#include "hash-ops.h"
|
|
|
|
#ifndef __FreeBSD__
|
|
#include <alloca.h>
|
|
#else
|
|
#include <stdlib.h>
|
|
#endif
|
|
|
|
/// Quick check if this is power of two (use on unsigned types; in this case for size_t only)
|
|
bool ispowerof2_size_t(size_t x) {
|
|
return x && !(x & (x - 1));
|
|
}
|
|
|
|
/***
|
|
* Round to power of two, for count>=3 and for count being not too large (as reasonable for tree hash calculations)
|
|
*/
|
|
size_t tree_hash_cnt(size_t count) {
|
|
assert( count >= 3); // cases for 0,1,2 are handled elsewhere
|
|
// Round down the count size: fun(2**n)= 2**(n-1) to round down to power of two
|
|
size_t tmp = count - 1;
|
|
size_t jj = 1;
|
|
for (jj=1 ; tmp != 0 ; ++jj) {
|
|
tmp /= 2; // dividing by 2 until to get how many powers of 2 fits size_to tmp
|
|
}
|
|
size_t cnt = 1 << (jj-2); // cnt is the count, but rounded down to power of two
|
|
// printf("count=%zu cnt=%zu jj=%zu tmp=%zu \n" , count,cnt,jj,tmp);
|
|
assert( cnt > 0 ); assert( cnt >= count/2 ); assert( cnt <= count );
|
|
assert( ispowerof2_size_t( cnt ));
|
|
return cnt;
|
|
}
|
|
|
|
void tree_hash(const char (*hashes)[HASH_SIZE], size_t count, char *root_hash) {
|
|
// The blockchain block at height 202612 http://monerochain.info/block/bbd604d2ba11ba27935e006ed39c9bfdd99b76bf4a50654bc1e1e61217962698
|
|
// contained 514 transactions, that triggered bad calculation of variable "cnt" in the original version of this function
|
|
// as from CryptoNote code.
|
|
//
|
|
// This bug applies to all CN altcoins.
|
|
//
|
|
// Mathematical bug here was first published on 14:45:34 (GMT+2) 2014-09-04 by Rafal Freeman <rfree>
|
|
// https://github.com/rfree2monero/bitmonero/commit/b417abfb7a297d09f1bbb6de29030f8de9952ac8
|
|
// and soon also applied to CryptoNote (15:10 GMT+2), and BoolBerry used not fully correct work around:
|
|
// the work around of sizeof(size_t)*8 or <<3 as used before in 2 coins and in BBL later was blocking
|
|
// exploitation on normal platforms, how ever we strongly recommend the following fix because it removes
|
|
// mistake in mathematical formula.
|
|
|
|
assert(count > 0);
|
|
if (count == 1) {
|
|
memcpy(root_hash, hashes, HASH_SIZE);
|
|
} else if (count == 2) {
|
|
cn_fast_hash(hashes, 2 * HASH_SIZE, root_hash);
|
|
} else {
|
|
size_t i, j;
|
|
|
|
size_t cnt = tree_hash_cnt( count );
|
|
size_t max_size_t = (size_t) -1; // max allowed value of size_t
|
|
assert( cnt < max_size_t/2 ); // reasonable size to avoid any overflows. /2 is extra; Anyway should be limited much stronger by logical code
|
|
// as we have sane limits on transactions counts in blockchain rules
|
|
|
|
char (*ints)[HASH_SIZE];
|
|
size_t ints_size = cnt * HASH_SIZE;
|
|
ints = alloca(ints_size); memset( ints , 0 , ints_size); // allocate, and zero out as extra protection for using uninitialized mem
|
|
|
|
memcpy(ints, hashes, (2 * cnt - count) * HASH_SIZE);
|
|
|
|
for (i = 2 * cnt - count, j = 2 * cnt - count; j < cnt; i += 2, ++j) {
|
|
cn_fast_hash(hashes[i], 64, ints[j]);
|
|
}
|
|
assert(i == count);
|
|
|
|
while (cnt > 2) {
|
|
cnt >>= 1;
|
|
for (i = 0, j = 0; j < cnt; i += 2, ++j) {
|
|
cn_fast_hash(ints[i], 64, ints[j]);
|
|
}
|
|
}
|
|
|
|
cn_fast_hash(ints[0], 64, root_hash);
|
|
}
|
|
}
|