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util: Avoid invalid integer negation in FormatMoney: make FormatMoney(const CAmount& n) well-defined also when n is std::numeric_limits<CAmount>::min()

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practicalswift 2020-11-16 15:42:36 +00:00
parent b9f41df1ea
commit 7cc75c9ba3
4 changed files with 20 additions and 7 deletions
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3
src/test/fuzz/integer.cpp
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@ -84,8 +84,7 @@ FUZZ_TARGET_INIT(integer, initialize_integer)
(void)DecompressAmount(u64); (void)DecompressAmount(u64);
(void)FormatISO8601Date(i64); (void)FormatISO8601Date(i64);
(void)FormatISO8601DateTime(i64); (void)FormatISO8601DateTime(i64);
// FormatMoney(i) not defined when i == std::numeric_limits<int64_t>::min() {
if (i64 != std::numeric_limits<int64_t>::min()) {
int64_t parsed_money; int64_t parsed_money;
if (ParseMoney(FormatMoney(i64), parsed_money)) { if (ParseMoney(FormatMoney(i64), parsed_money)) {
assert(parsed_money == i64); assert(parsed_money == i64);

10
src/test/util_tests.cpp
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@ -1180,6 +1180,16 @@ BOOST_AUTO_TEST_CASE(util_FormatMoney)
BOOST_CHECK_EQUAL(FormatMoney(COIN/1000000), "0.000001"); BOOST_CHECK_EQUAL(FormatMoney(COIN/1000000), "0.000001");
BOOST_CHECK_EQUAL(FormatMoney(COIN/10000000), "0.0000001"); BOOST_CHECK_EQUAL(FormatMoney(COIN/10000000), "0.0000001");
BOOST_CHECK_EQUAL(FormatMoney(COIN/100000000), "0.00000001"); BOOST_CHECK_EQUAL(FormatMoney(COIN/100000000), "0.00000001");
BOOST_CHECK_EQUAL(FormatMoney(std::numeric_limits<CAmount>::max()), "92233720368.54775807");
BOOST_CHECK_EQUAL(FormatMoney(std::numeric_limits<CAmount>::max() - 1), "92233720368.54775806");
BOOST_CHECK_EQUAL(FormatMoney(std::numeric_limits<CAmount>::max() - 2), "92233720368.54775805");
BOOST_CHECK_EQUAL(FormatMoney(std::numeric_limits<CAmount>::max() - 3), "92233720368.54775804");
// ...
BOOST_CHECK_EQUAL(FormatMoney(std::numeric_limits<CAmount>::min() + 3), "-92233720368.54775805");
BOOST_CHECK_EQUAL(FormatMoney(std::numeric_limits<CAmount>::min() + 2), "-92233720368.54775806");
BOOST_CHECK_EQUAL(FormatMoney(std::numeric_limits<CAmount>::min() + 1), "-92233720368.54775807");
BOOST_CHECK_EQUAL(FormatMoney(std::numeric_limits<CAmount>::min()), "-92233720368.54775808");
} }
BOOST_AUTO_TEST_CASE(util_ParseMoney) BOOST_AUTO_TEST_CASE(util_ParseMoney)

12
src/util/moneystr.cpp
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@ -9,13 +9,17 @@
#include <util/strencodings.h> #include <util/strencodings.h>
#include <util/string.h> #include <util/string.h>
std::string FormatMoney(const CAmount& n) std::string FormatMoney(const CAmount n)
{ {
// Note: not using straight sprintf here because we do NOT want // Note: not using straight sprintf here because we do NOT want
// localized number formatting. // localized number formatting.
int64_t n_abs = (n > 0 ? n : -n); static_assert(COIN > 1);
int64_t quotient = n_abs/COIN; int64_t quotient = n / COIN;
int64_t remainder = n_abs%COIN; int64_t remainder = n % COIN;
if (n < 0) {
quotient = -quotient;
remainder = -remainder;
}
std::string str = strprintf("%d.%08d", quotient, remainder); std::string str = strprintf("%d.%08d", quotient, remainder);
// Right-trim excess zeros before the decimal point: // Right-trim excess zeros before the decimal point:

2
src/util/moneystr.h
View file

@ -17,7 +17,7 @@
/* Do not use these functions to represent or parse monetary amounts to or from /* Do not use these functions to represent or parse monetary amounts to or from
* JSON but use AmountFromValue and ValueFromAmount for that. * JSON but use AmountFromValue and ValueFromAmount for that.
*/ */
std::string FormatMoney(const CAmount& n); std::string FormatMoney(const CAmount n);
/** Parse an amount denoted in full coins. E.g. "0.0034" supplied on the command line. **/ /** Parse an amount denoted in full coins. E.g. "0.0034" supplied on the command line. **/
[[nodiscard]] bool ParseMoney(const std::string& str, CAmount& nRet); [[nodiscard]] bool ParseMoney(const std::string& str, CAmount& nRet);