conflux-rust
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Conflux-Chain
potential arithmetic overflow in `fn finalize`
Actually can we use some tool to detect all potential arithmetic overflow?
The particular place has very low severity since It's not likely to happen outside testing environment, as nobody could spend extremely high gas fee. But how about other places?
The gas used in a transaction can not exceed the maximum gas allowed in one block, which is must less than 2^256
BTW, "charge_all" actually means to charge_75_percent in the code.
Yes, we will refund at most 1/4 * tx.gas.
The gas used in a transaction can not exceed the maximum gas allowed in one block, which is must less than 2^256
3*gas_left may overflow in theory. But unlikely since nobody has too much CFX. I raise this issue mainly to ask if we have a way to find out all potential overflow.
3*gas_left may overflow in theory. But unlikely since nobody has too much CFX.
It is not because of the transanction fee, because the gas_price cound equal to 0. But the maximum gas allowed in the whole block is limited.
I raise this issue mainly to ask if we have a way to find out all potential overflow.
If an overflow happens for struct U256 and U512, the basic operation will cause a panic. You can read the source code of crate uint, which provides a macro implementing fixed-length big integer like U256 and U512.
impl<T> $crate::core_::ops::Add<T> for $name where T: Into<$name> {
type Output = $name;
fn add(self, other: T) -> $name {
let (result, overflow) = self.overflowing_add(other.into());
$crate::panic_on_overflow!(overflow);
result
}
}
impl $crate::core_::ops::Mul<$other> for $name {
type Output = $name;
fn mul(self, other: $other) -> $name {
let bignum: $name = other.into();
let (result, overflow) = self.overflowing_mul(bignum);
$crate::panic_on_overflow!(overflow);
result
}
}
But the addition overflow in u64 will not cause a panic in release mode. I'm sorry for forgotting where I read this.
please, the code is hard to understand. please add more description here. add TODO here, if someone clearly and provides some elegant way, he will fix it later.
