Questions tagged [delegatecall]
The delegatecall tag has no usage guidance.
94
questions
1
vote
1answer
25 views
Usecase for approve and allowance functions of ERC20 token
Could you please enlighten me on how approve and allowance functions work using a usecase? I dont understand the underlying operations of these functions. Especially, when a token owner delegates the ...
0
votes
1answer
24 views
How do you call a fallback function that uses msg.data for parameters
I am trying to complete a homework assignment, so I am not doing something malicious. The goal is to learn the vulnerabilities of contracts. I want to call the fallback function of wallet to trigger ...
2
votes
1answer
54 views
How to perform delegate call inside of view call (staticall)?
Inside view method it's not possible to do delegatecall due to compilation errors. Is there any way to delegate view calls?
0
votes
1answer
34 views
Dynamic Delegate Proxy contract
I'm familiar with proxy contracts in solidity using the 'delegatecall' to separate out the proxy contract from the logic contract. Is there a simple way to choose the logic contract based on an ...
0
votes
1answer
50 views
Factory contract to clone existing contracts
I am researching about Factory contract to clone existing contracts, First is the implementation present at https://github.com/optionality/clone-factory/blob/master/contracts/CloneFactory.sol. I don't ...
1
vote
0answers
38 views
What are “if” and “this” in this function?
function() public {
if(delegate.delegatecall(msg.data)) {
this;
What are the requirements for "if" to execute "this" and what does "this" refer to in this function?
0
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0answers
43 views
Safe usage of delegatecall
Hey guys I have a few questions about delegatecall.
The setup:
I have 2 contracts A and B.
A has 2 uint state variables
B has 4 uint state variables
To ensure storage layout compatibility, B ...
0
votes
1answer
39 views
Upgradable contract proxy pattern: Get the invoked method name in the fallback function
I have a proxy smart contract and I would like to get the name of the called method in the fallback function. Is there a way?
For example, if I call the function getName() (stored in the logic ...
1
vote
0answers
20 views
How dangerous is this: number of contracts contain a function like “approveandcall” which lets anyone call any contract (some thoughts?)
The most common implementation is as follows:
function approveAndCall(address _spender, uint256 _value, bytes _extraData) public returns (bool success) {
tokenRecipient spender = tokenRecipient(...
1
vote
1answer
49 views
How to use call, delegate call?
I have created two contracts A and B as follow:
Contract A:
pragma solidity 0.4.25;
contract A{
// uint public X ;
event MyName(address _from, address sender);
function checkMe(uint val)...
0
votes
0answers
55 views
How to use delegate call with or without arguments functions?
Below is my contract:
contract A{
mapping (address => uint) public balances;
function put() payable public {
balances[msg.sender] = msg.value;
}
function get(address ...
0
votes
1answer
58 views
Using delegatecall for multiple parameters fuction in solidity
Does someone have a exemple of solidity delegatecall for multiple parameters function?
10
votes
2answers
359 views
Pros and Cons of smart contract upgradable patterns
There have been quite many arguments around how to achieve smart contract updates like Upgradeable smart contracts.
I feel Proxycontract with Delegate-call is currently the most famous one. But aside ...
0
votes
0answers
45 views
No Events After Deploying Another Contract in Remix
I am trying to write an upgradable smart contract in Remix. This involves a Proxy contract, a Logic_0_1_0 contract, and a Logic_0_2_0 contract.
I uploaded Proxy and Logic_0_1_0 only, and the ...
2
votes
1answer
220 views
Delegatecall return values solidity 5.0
With solidity 5.0+ , the delegatecall function can return a boolean and a bytes representing return value. I want to understand how does one convert the returned bytes to various datatypes. ex
If ...
0
votes
1answer
26 views
Calling Msg.sender Natively
Caller -> Contract B -> Contract A
Contract A has a msg.sender variable.
I want to use the Caller as Msg.Sender for Contract A through Contract B.
How is this done?
0
votes
1answer
41 views
How do you pause a Proxy-Logic pattern?
Suppose we have a Proxy contract that forwards to call to a Logic contract by using delegatecall.
If we pause the Proxy, users will still be able to directly interact with the Logic contract. While ...
1
vote
1answer
132 views
What's the equivalent of Vyper's create_forwarder_to in Solidity?
In Vyper, there's a built-in function called create_forwarder_to, which
Duplicates a contract’s code and deploys it as a new instance, by means of a DELEGATECALL.
If my understanding is correct, ...
1
vote
0answers
91 views
delegatecall (assembly) didn't change state variable in Remix with Web3 Provider
I am trying to test proxy pattern in Remix, which connected to my private chain with Web3 Provider. By the way, miner is working all the time. After invoking add function of Proxy contract, the state ...
1
vote
0answers
114 views
Anything like a static delegatecall from a view function?
let's say there are two contracts A and B, where A calls methods in B. I understand that A can modify and read storage in B with B.call() and B.staticcall(), ie. A can execute B's methods in the ...
0
votes
1answer
42 views
pass storage through interface to library
Here is what am i doing:
There is a library, accept storage argument as parameter, then do some math and return the result.
And there is a contract to call the function in the library, and an extra ...
1
vote
1answer
112 views
Correct way to make a delegatecall? [duplicate]
I made a delegatecall to the REP contract to approve my contract to spend tokens on behalf of a user and my transaction is failing for some reason here is my code:
(bool b,) = REPAddress.delegatecall(...
0
votes
1answer
43 views
Unstructured storage proxies. Variables not being overwritten?
When using delegate call I was under the impression that storage slots declared in the proxy will be overwritten by the implementation.
Unstructured storage implementations declare bytes32 variables ...
1
vote
1answer
67 views
How to prevent the code of my contract being used in a CALLCODE?
Simple question but I couldn’t find the answer anywhere.
How to know if the code of my contract is used in a CALLCODE or DELEGATECALL by third party sinceaddress(this)returns the address of the caller ...
0
votes
0answers
60 views
Delegatecall not changing state
I was trying the code in https://gist.github.com/sogoiii/f0ced0a4e569b5f38d302e7072d78b43 to observe the difference between call and delegatecall.
pragma solidity ^0.4.18;
contract D {
uint public ...
0
votes
1answer
206 views
Difference in “delegate call via assembly”
I came across a different version of delegate call via assembly and also tried all of them - no different result so far. How does it differ and which is the best version to use?
OpenZepplin version:
...
1
vote
0answers
68 views
Subtraces of delegatecall in Parity trace
I'm investigating transactions using Parity trace which provides useful data over a transaction flow. Among this data is the Subtraces field which allows me to understand how many sub-calls each ...
0
votes
1answer
59 views
DelegateCall to internal function doesn't store variable
Why isn't delegate call able to run internal functions?
What is the difference between a self directed delegate call and a contract normally calling one of it's internal function?
contract ...
0
votes
2answers
136 views
Code Example from “Mastering Ethereum: Building Smart Contracts and DApps” doesn't work
I'm reading the Ethereum book of Gavin Wood right know and the following code example gives an error message when I try to compile it with truffle:
pragma solidity ^0.4.22;
contract calledContract {
...
1
vote
0answers
122 views
Proxy contract DELEGATECALL to pass a DYNAMIC array to a function in the target contract
I'm trying to get a Proxy contract to correctly do a delegatecall to a function in another 'target' contract. The problem is, that I need to pass a dynamic array as the parameter to this function.
Q: ...
1
vote
0answers
39 views
Replaying the Bad Parity Hack
On a locally hosted instance of Ethererum I am trying to replay and understand the Bad Parity hack. I have a Wallet and a Wallet Library Contract.
Wallet.sol
constructor(address lib) public payable {...
0
votes
1answer
290 views
Is it possible to send Ether using delegatecall?
I tested this in Remix and it seems that the ether remains in the delegator contract and doesn't get forwarded. Using the code below to test:
contract SomeContract {
address public sender;
...
1
vote
0answers
152 views
How would you use a proxy erc20 contract if you cannot preserve msg.sender?
Let's say I use a proxy contract which allows me to make an ERC20 token transfer from my account.
At the moment the only way to do so is to use tx.origin which gets the original EOA address of the ...
0
votes
1answer
149 views
Delegatecall: Storing values
Using a delegatecall() to call another contract will have that contract run from within your context (e.g. if it calls a contract on its turn as a result, msg.sender will be your address). I am aware ...
0
votes
0answers
153 views
How to allow delegatecall only from specific contract?
I have a token contract, when transfer is called it calls other contract's transfer with data. Other contract checks msg.sender and allows only the first contract to pass and performs some important ...
0
votes
1answer
411 views
How to use Role-Based Access Control via Proxy?
I have a PermissionsManager contract that uses OpenZeppelin's Role-Based Access Control (RBAC) template as a base. Currently function modifiers in my app call PermissionsManager directly to check for ...
2
votes
1answer
2k views
How does delegatecall work from Solidity 0.5.0 onwards?
I am trying, for learning purposes only, to make a mutable smart contract, but I couldn't find anything useful on stackexchange because everything I found was using pragma solidity ^0.4.x;
So, I have ...
1
vote
0answers
95 views
Can anyone give me a working DELEGATECALL example? [duplicate]
I tried many variants of DELEGATECALL, but not one of them gave me the desired result.
When used in assembly: = delegatecall (), I also don't get the result.
I also used different versions of Solidity ...
2
votes
1answer
358 views
Calling fallback function in truffle to delegate a call
I'm playing with the upgradeable contracts via DelegateProxy in Solidity.
This pattern posits that a MutableForwarder contract is deployed once, and all the subsequent calls to the upgradeable ...
0
votes
1answer
168 views
Proxy Contract Not Updating Store Data
I want to setup a proxy contract that my users can interact with. The proxy contract is a store contract with stores the user's age for now. When I call writeData to update my age, I expect it to call ...
1
vote
1answer
236 views
contract kill function
as per ethereum docs
Even if a contract’s code does not contain a call to selfdestruct, it
can still perform that operation using delegatecall or callcode.
is this real?
1.if it is then even if ...
2
votes
1answer
119 views
How does a contract know which library to query or know the library address?
How does a contract know which library to query? For Example in the code below (The code is from solidity docs: https://solidity.readthedocs.io/en/v0.4.24/contracts.html?highlight=library#libraries
...
3
votes
0answers
35 views
Delegatecall Scope - Correct me if I'm wrong
When any contract function is called - delegatecall or otherwise - the EVM loads the requisite pointers & values into that call frame's volatile stack/memory.
Example:
Let's say we have contract ...
2
votes
3answers
597 views
Scope confusion using delegate call
I am having trouble understanding the scope with delegatecall method. Here are my two contracts:
contract Caller {
uint public testVar = 88;
uint public myVariable = 6;
function ...
2
votes
2answers
552 views
Double delegate call doesn't work
To create an upgradeable contract I have to use multiple proxies. The contract applies to Proxy A, then Proxy A applies to Proxy B. But delegatecall doesn't work in this case.
The simplified code of ...
2
votes
1answer
352 views
Use of delegatecall with msg.data
I'm trying to understand below code:
pragma solidity ^0.4.23;
contract Relay {
address public currentVersion;
address public owner;
modifier onlyOwner() {
require(msg.sender == ...
0
votes
1answer
168 views
Delegatecall require statement does not cause an abortion in any way
This is a sequel to a previous question of mine.
I want to implement a validation function (e.g. for passwords) within a central contract, that could be used by other contracts. It is important to ...
0
votes
1answer
122 views
What method can I use instead of delegatecall?
I see the warning security/no-low-level-calls: Avoid using low-level function 'delegatecall' when I use delegatecall function in my code.
I understand why it's not a good way, but I still need that ...
1
vote
0answers
102 views
delegatecall for Smart Contract versioning
I've a state variable
address public current;
which stores the address of the latest updated contract. This value can be modified with a function.
Then, I've a function of this kind
function ...
1
vote
1answer
784 views
Solidity - selfdestruct
I'm just wondering what would happen if I don't put a selfdestrut() method in my smart contract.
As I read from the Solidity documentation (Self-destruct):
Even if a contract’s code does not ...
