lbrycrd/src/uint256.cpp
Wladimir J. van der Laan 085cac6b90
Merge #14734: fix an undefined behavior in uint::SetHex
0f459d868d fix an undefined behavior in uint::SetHex (Kaz Wesley)

Pull request description:

  Decrementing psz beyond the beginning of the string is UB, even though
  the out-of-bounds pointer is never dereferenced.

  I don't think any clang sanitizer covers this, so I don't see any way a test could catch the original behavior.

ACKs for top commit:
  promag:
    utACK 0f459d8.
  l2a5b1:
    utACK 0f459d868d

Tree-SHA512: 388223254ea6e955f643d2ebdf74d15a3d494e9f0597d9f05987ebb708d7a1cc06ce64bd25d447d75b5f5561bdae9630dcf25adb7bd75f7a382298b95d127162
2019-07-03 14:18:29 +02:00

78 lines
2.2 KiB
C++

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2018 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include <uint256.h>
#include <util/strencodings.h>
#include <stdio.h>
#include <string.h>
template <unsigned int BITS>
base_blob<BITS>::base_blob(const std::vector<unsigned char>& vch)
{
assert(vch.size() == sizeof(data));
memcpy(data, vch.data(), sizeof(data));
}
template <unsigned int BITS>
std::string base_blob<BITS>::GetHex() const
{
return HexStr(std::reverse_iterator<const uint8_t*>(data + sizeof(data)), std::reverse_iterator<const uint8_t*>(data));
}
template <unsigned int BITS>
void base_blob<BITS>::SetHex(const char* psz)
{
memset(data, 0, sizeof(data));
// skip leading spaces
while (IsSpace(*psz))
psz++;
// skip 0x
if (psz[0] == '0' && ToLower(psz[1]) == 'x')
psz += 2;
// hex string to uint
size_t digits = 0;
while (::HexDigit(psz[digits]) != -1)
digits++;
unsigned char* p1 = (unsigned char*)data;
unsigned char* pend = p1 + WIDTH;
while (digits > 0 && p1 < pend) {
*p1 = ::HexDigit(psz[--digits]);
if (digits > 0) {
*p1 |= ((unsigned char)::HexDigit(psz[--digits]) << 4);
p1++;
}
}
}
template <unsigned int BITS>
void base_blob<BITS>::SetHex(const std::string& str)
{
SetHex(str.c_str());
}
template <unsigned int BITS>
std::string base_blob<BITS>::ToString() const
{
return (GetHex());
}
// Explicit instantiations for base_blob<160>
template base_blob<160>::base_blob(const std::vector<unsigned char>&);
template std::string base_blob<160>::GetHex() const;
template std::string base_blob<160>::ToString() const;
template void base_blob<160>::SetHex(const char*);
template void base_blob<160>::SetHex(const std::string&);
// Explicit instantiations for base_blob<256>
template base_blob<256>::base_blob(const std::vector<unsigned char>&);
template std::string base_blob<256>::GetHex() const;
template std::string base_blob<256>::ToString() const;
template void base_blob<256>::SetHex(const char*);
template void base_blob<256>::SetHex(const std::string&);