mirror of https://github.com/status-im/EIPs.git
122 lines
4.2 KiB
Markdown
122 lines
4.2 KiB
Markdown
|
---
|
|||
|
|
eip: 1985
|
|||
|
|
title: Sane limits for certain EVM parameters
|
|||
|
|
author: Alex Beregszaszi (@axic), Paweł Bylica (@chfast)
|
|||
|
|
discussions-to: https://ethereum-magicians.org/t/eip-1985-sane-limits-for-certain-evm-parameters/3224
|
|||
|
|
status: Draft
|
|||
|
|
type: Standards Track
|
|||
|
|
category: Core
|
|||
|
|
created: 2018-08-01
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
## Abstract
|
|||
|
|
|
|||
|
|
Introduce an explicit value range for certain EVM parameters
|
|||
|
|
(such as gas limit, block number, block timestamp, size field when returning/copying data within EVM).
|
|||
|
|
Some of these already have an implicit value range due to various (practical) reasons.
|
|||
|
|
|
|||
|
|
## Motivation
|
|||
|
|
|
|||
|
|
Having such an explicit value range can help in creating compatible client implementations,
|
|||
|
|
in certain cases it can also offer minor speed improvements,
|
|||
|
|
and can reduce the effort needed to create consensus critical test cases
|
|||
|
|
by eliminating unrealistic edge cases.
|
|||
|
|
|
|||
|
|
## Specification
|
|||
|
|
|
|||
|
|
If `block.number >= {FORK_BLOCK}`, the following value ranges are introduced.
|
|||
|
|
They restrict the results (i.e. values pushed to the stack) of the opcodes listed below.
|
|||
|
|
|
|||
|
|
1. *gas*, *gas limit*, *block gas limit*
|
|||
|
|
is a range between `0` and `9223372036854775807` (`2**63 - 1`).
|
|||
|
|
It affects following the opcodes:
|
|||
|
|
- `GASLIMIT` (`0x45`),
|
|||
|
|
- `GAS` (`0x5a`).
|
|||
|
|
|
|||
|
|
2. *block number*, *timestamp*
|
|||
|
|
is a range between `0` and `9223372036854775807` (`2**63 - 1`).
|
|||
|
|
It affects the following opcodes:
|
|||
|
|
- `TIMESTAMP` (`0x42`),
|
|||
|
|
- `NUMBER` (`0x43`).
|
|||
|
|
|
|||
|
|
3. *account address*
|
|||
|
|
is a range between `0` and `1461501637330902918203684832716283019655932542975` (`2**160 - 1`).
|
|||
|
|
It affects the following opcodes:
|
|||
|
|
- `ADDRESS` (`0x30`),
|
|||
|
|
- `ORIGIN` (`0x32`),
|
|||
|
|
- `CALLER` (`0x33`),
|
|||
|
|
- `COINBASE` (`0x41`),
|
|||
|
|
- `CREATE` (`0xf0`),
|
|||
|
|
- `CREATE2` (`0xf5`).
|
|||
|
|
|
|||
|
|
4. *buffer size*
|
|||
|
|
is a range between `0` and `4294967295` (`2**32 - 1`).
|
|||
|
|
It affects the following opcodes:
|
|||
|
|
- `CALLDATASIZE` (`0x36`),
|
|||
|
|
- `CODESIZE` (`0x38`),
|
|||
|
|
- `EXTCODESIZE` (`0x3b`),
|
|||
|
|
- `RETURNDATASIZE` (`0x3d`),
|
|||
|
|
- `MSIZE` (`0x59`).
|
|||
|
|
|
|||
|
|
|
|||
|
|
## Rationale
|
|||
|
|
|
|||
|
|
These limits have been:
|
|||
|
|
- proposed by [EVMC]
|
|||
|
|
- implemented partially by certain clients, such as [Aleth], [geth], [Parity] and [ethereumjs]
|
|||
|
|
- allowed by certain test cases in the [Ethereum testing suite]
|
|||
|
|
- and implicitly also allowed by certain assumptions, such as due to gas limits some of these values cannot grow past a certain limit
|
|||
|
|
|
|||
|
|
Most of the limits proposed in this document have been previously explored and tested in [EVMC].
|
|||
|
|
|
|||
|
|
Using the `2**63 - 1` constant to limit some of the ranges:
|
|||
|
|
- allows using signed 64-bit integer type to represent it,
|
|||
|
|
what helps programming languages not having unsigned types,
|
|||
|
|
- makes arithmetic simpler (e.g. checking out-of-gas conditions is simple as `gas_counter < 0`).
|
|||
|
|
|
|||
|
|
### Timestamp
|
|||
|
|
|
|||
|
|
The [Yellow Paper] defines the timestamp in block as "A scalar value equal to the reasonable output of Unix’s time() at this block’s inception".
|
|||
|
|
IEEE Std 1003.1-2001 (POSIX.1) leaves that definition implementation defined.
|
|||
|
|
|
|||
|
|
### Addresses
|
|||
|
|
|
|||
|
|
The size of addresses is specified in the [Yellow Paper] as 20 bytes.
|
|||
|
|
E.g. the `COINBASE` instruction is specified to return *H*<sub>c</sub> ∈ 𝔹<sub>20</sub> which has 20 bytes.
|
|||
|
|
|
|||
|
|
### Comparing current implementations
|
|||
|
|
|
|||
|
|
- Timestamp is implemented as a 64-bit value in [Aleth], [geth] and [Parity]
|
|||
|
|
- Block gas limit is implemented as a 64-bit in [Aleth] and [geth]
|
|||
|
|
|
|||
|
|
## Backwards Compatibility
|
|||
|
|
|
|||
|
|
All of these limits are already enforced mostly through the block gas limit. Since the out of range case results in a transaction failure, there should not be a change in behaviour.
|
|||
|
|
|
|||
|
|
## Test Cases
|
|||
|
|
|
|||
|
|
TBA
|
|||
|
|
|
|||
|
|
## Implementation
|
|||
|
|
|
|||
|
|
TBA
|
|||
|
|
|
|||
|
|
## References
|
|||
|
|
|
|||
|
|
[EIP-106](https://github.com/ethereum/EIPs/issues/106) proposed the block gas limit to be limited at `2**63 - 1`.
|
|||
|
|
|
|||
|
|
## TODO
|
|||
|
|
|
|||
|
|
1. Does the gas limit apply to the gas argument for call instructions?
|
|||
|
|
|
|||
|
|
## Copyright
|
|||
|
|
Copyright and related rights waived via [CC0](https://creativecommons.org/publicdomain/zero/1.0/).
|
|||
|
|
|
|||
|
|
[EVMC]: https://github.com/ethereum/evmc
|
|||
|
|
[Aleth]: https://github.com/ethereum/aleth
|
|||
|
|
[geth]: https://github.com/ethereum/go-ethereum
|
|||
|
|
[Parity]: https://github.com/paritytech/parity-ethereum
|
|||
|
|
[ethereumjs]: https://github.com/ethereumjs
|
|||
|
|
[Ethereum testing suite]: https://github.com/ethereum/tests
|
|||
|
|
[Yellow Paper]: https://github.com/ethereum/yellowpaper
|