do {
// Don't overflow.
- if (result > (UINT64_MAX - 9) / 10)
+ if (result > UINT64_MAX / 10)
goto error;
result *= 10;
- result += *value - '0';
+
+ // Another overflow check
+ const uint32_t add = *value - '0';
+ if (UINT64_MAX - add < result)
+ goto error;
+
+ result += add;
++value;
} while (*value >= '0' && *value <= '9');
/// \brief Convert a string to uint64_t
///
/// This is rudely copied from src/xz/util.c and modified a little. :-(
+/// Since this function is used only for parsing the memory usage limit,
+/// this cheats a little and saturates too big values to UINT64_MAX instead
+/// of giving an error.
///
/// \param max Return value when the string "max" was specified.
///
do {
// Don't overflow.
- if (result > (UINT64_MAX - 9) / 10)
+ if (result > UINT64_MAX / 10)
return UINT64_MAX;
result *= 10;
- result += *value - '0';
+
+ // Another overflow check
+ const uint32_t add = *value - '0';
+ if (UINT64_MAX - add < result)
+ return UINT64_MAX;
+
+ result += add;
++value;
} while (*value >= '0' && *value <= '9');