Mercurial > hg > bitcoin
changeset 2730:08da9d05fd0b draft
Don't overflow signed ints in CBigNum::setint64().
CBigNum::setint64() does 'n <<= 8', where n is of type "long long".
This leads to shifting onto and past the sign bit, which is undefined
behavior in C++11 and can cause problems in the future.
author | Ricardo M. Correia <rcorreia@wizy.org> |
---|---|
date | Mon, 14 May 2012 02:50:01 +0200 |
parents | b9a0ca01e731 |
children | bc9d81f89e3f |
files | src/bignum.h |
diffstat | 1 files changed, 11 insertions(+), 5 deletions(-) [+] |
line wrap: on
line diff
--- a/src/bignum.h +++ b/src/bignum.h @@ -122,16 +122,22 @@ return (n > (unsigned long)std::numeric_limits<int>::max() ? std::numeric_limits<int>::min() : -(int)n); } - void setint64(int64 n) + void setint64(int64 sn) { - unsigned char pch[sizeof(n) + 6]; + unsigned char pch[sizeof(sn) + 6]; unsigned char* p = pch + 4; - bool fNegative = false; - if (n < (int64)0) + bool fNegative; + uint64 n; + + if (sn < (int64)0) { - n = -n; + n = -sn; fNegative = true; + } else { + n = sn; + fNegative = false; } + bool fLeadingZeroes = true; for (int i = 0; i < 8; i++) {