[UNI-V2-DAI-ETH] ERC20 Token Smart Contract Technical Assessment

[hexonaut]

[UNI-V2-DAI-ETH] ERC20 Token Smart Contract Technical Assessment

General Information

• Symbol : UNI-V2
• Address(es) :
  • UniswapV2Pair: 0xA478c2975Ab1Ea89e8196811F51A7B7Ade33eB11
• Deployment Date :
  • UniswapV2Pair: May-11-2020 02:30:13 AM +UTC
• Total supply : 7915350838566798281954065 WAD (791,535 units)
• Developers allotment : None
• Collateral Onboarding Application: [UNI-V2-DAI-ETH] Uniswap V2 Dai-Eth Liquidity Token Collateral Application
• Project website : https://app.uniswap.org/
• Github repository :
  • https://github.com/Uniswap
• Can use existing MCD collateral type adapter?
  Partially, the standard GemJoin adapter works if you ignore rewards. A custom gem join adapter is required to distribute UNI rewards.

Risk Summary

• Does the contract implement the ERC20 token standards? Yes.
• Risk analysis : LOW.

Technical Information

• Compiler version : v0.5.16+commit.9c3226ce
• Decimals : 18
• Overflow checks : Yes, the contract uses the SafeMath library for uint operations.
• Mitigation against allowance race-condition : No.
• Upgradeable contract patterns : No.
• Access control or restriction lists : No.
• Non-standard features or behaviors : No.

Formal Verification Considerations:

• Does transfer have simple semantics? Yes.
• Does transferFrom have simple semantics? Yes.
• Can balances be arbitrarily modified by some actor? No.
• Are there any external calls? No.

Testnet Information

• Uniswap is deployed on Ropsten, Rinkeby, Gorli and Kovan. List of relevant addresses here.

Contract Logic Summary

Administrative Addresses

• Fee Setter: 0x5e4be8Bc9637f0EAA1A755019e06A68ce081D58F
  • Fee setter can turn fees on and off and set the target address that recieves fees. This address is controlled by Uniswap Governance and is behind a time lock of 48 hours.

Inheritance Structure

UNI-V2-DAI-ETH uses custom minting/burning logic in UniswapV2Pair which extends UniswapV2ERC20.

Other

UniswapV2ERC20 also implements permit for gasless transactions.

Contract Risk Summary

This is a low risk contract. The ERC20 functions are implemented to industry standard, there are checks to prevent over/underflows, and the contract is non-upgradeable. Uniswap LP tokens are very safe by themselves. The risk comes from the underlying tokens. Both ETH and DAI are safe from a smart contract point of view.

Supporting Materials

Architecture Diagram

Inheritance Diagram

Sūrya’s Description Report

Files Description Table

File Name	SHA-1 Hash
UniswapV2Pair-All.sol	f5e7366252c794b5fe2bf7bd2c1ce82240138de2

Contracts Description Table

Contract	Type	Bases
└	Function Name	Visibility	Mutability	Modifiers
IUniswapV2Pair	Interface
└	name	External		NO❗️
└	symbol	External		NO❗️
└	decimals	External		NO❗️
└	totalSupply	External		NO❗️
└	balanceOf	External		NO❗️
└	allowance	External		NO❗️
└	approve	External		NO❗️
└	transfer	External		NO❗️
└	transferFrom	External		NO❗️
└	DOMAIN_SEPARATOR	External		NO❗️
└	PERMIT_TYPEHASH	External		NO❗️
└	nonces	External		NO❗️
└	permit	External		NO❗️
└	MINIMUM_LIQUIDITY	External		NO❗️
└	factory	External		NO❗️
└	token0	External		NO❗️
└	token1	External		NO❗️
└	getReserves	External		NO❗️
└	price0CumulativeLast	External		NO❗️
└	price1CumulativeLast	External		NO❗️
└	kLast	External		NO❗️
└	mint	External		NO❗️
└	burn	External		NO❗️
└	swap	External		NO❗️
└	skim	External		NO❗️
└	sync	External		NO❗️
└	initialize	External		NO❗️
IUniswapV2ERC20	Interface
└	name	External		NO❗️
└	symbol	External		NO❗️
└	decimals	External		NO❗️
└	totalSupply	External		NO❗️
└	balanceOf	External		NO❗️
└	allowance	External		NO❗️
└	approve	External		NO❗️
└	transfer	External		NO❗️
└	transferFrom	External		NO❗️
└	DOMAIN_SEPARATOR	External		NO❗️
└	PERMIT_TYPEHASH	External		NO❗️
└	nonces	External		NO❗️
└	permit	External		NO❗️
SafeMath	Library
└	add	Internal
└	sub	Internal
└	mul	Internal
UniswapV2ERC20	Implementation	IUniswapV2ERC20
└		Public		NO❗️
└	_mint	Internal
└	_burn	Internal
└	_approve	Private
└	_transfer	Private
└	approve	External		NO❗️
└	transfer	External		NO❗️
└	transferFrom	External		NO❗️
└	permit	External		NO❗️
Math	Library
└	min	Internal
└	sqrt	Internal
UQ112x112	Library
└	encode	Internal
└	uqdiv	Internal
IERC20	Interface
└	name	External		NO❗️
└	symbol	External		NO❗️
└	decimals	External		NO❗️
└	totalSupply	External		NO❗️
└	balanceOf	External		NO❗️
└	allowance	External		NO❗️
└	approve	External		NO❗️
└	transfer	External		NO❗️
└	transferFrom	External		NO❗️
IUniswapV2Factory	Interface
└	feeTo	External		NO❗️
└	feeToSetter	External		NO❗️
└	getPair	External		NO❗️
└	allPairs	External		NO❗️
└	allPairsLength	External		NO❗️
└	createPair	External		NO❗️
└	setFeeTo	External		NO❗️
└	setFeeToSetter	External		NO❗️
IUniswapV2Callee	Interface
└	uniswapV2Call	External		NO❗️
UniswapV2Pair	Implementation	IUniswapV2Pair, UniswapV2ERC20
└	getReserves	Public		NO❗️
└	_safeTransfer	Private
└		Public		NO❗️
└	initialize	External		NO❗️
└	_update	Private
└	_mintFee	Private
└	mint	External		lock
└	burn	External		lock
└	swap	External		lock
└	skim	External		lock
└	sync	External		lock

Legend

Symbol	Meaning
	Function can modify state
	Function is payable