EIP-2677: Limit size of `initcode`


  Ethereum Improvement Proposals
        
        
          
            
              
            
          
        

        AllCoreNetworkingInterfaceERCMetaInformational

      



      
        
  
    

  
    
    
      🛑 Withdrawn
    
    
    
    
      Standards Track: Core
    
  
  
    
      EIP-2677: Limit size of `initcode`
    
    
      
        
      
    
    
      
        
      
    
  

  

  	Authors	Martin Holst Swende (@holiman), Paweł Bylica (@chfast), Alex Beregszaszi (@axic)
	Created	2020-05-18
	Discussion Link	https://ethereum-magicians.org/t/eip-2677-limit-size-of-initcode/4550


  


  

  
    Table of Contents

    	Simple Summary
	Abstract
	Motivation
	Specification
	Rationale
	Backwards Compatibility
	Security Considerations
	Test Cases
	Implementation
	Copyright



  


  
      
      
         Simple Summary
      
      
    


Enforce a maximum size limit (max_initcode_size) of 49152 (0xc000) for initcode.

  
    
      
      
         Abstract
      
      
    


Enforce a maximum size limit (max_initcode_size) for initcode. If the size of initcode exceeds max_initcode_size, then contract creation fails with an out of gas error.


Since EIP-170 was implemented, there has been a size limit of 24576 (0x6000) on contract code. We propose to also limit the size of executable code to 2x the above limit, i.e. 49152 (0xc000).


This also leads to two nice properties:


	instruction offset in code fits 16-bit value,
	code size fits 16-bit value.


  
    
      
      
         Motivation
      
      
    


When a client executes initcode, the client has to perform a jumpdest analysis. In some cases, the client also performs a hash of the code:


	To use as a key in a mapping containing result of a jumpdest analysis
	To use for address calculation within CREATE2.



The work performed during a jumpdest analysis scales linearly with the size of the code. Currently, a transaction can expand the memory once, and reuse the same memory segment (with minor modifications) to force the client to perform a lot of analysis/hashing, leading to slow block processing.


Historically, this was exploited in June 2017, precipitating the 1.6.5-patch release of geth


The work performed during address calculation within CREATE2 is charged in proportion with size of the code.

  
    
      
      
         Specification
      
      
    


There are three situations where this is applicable:


	CREATE,
	CREATE2,
	creation using a transaction with empty receiver.



In all these (and future) cases, the EVM should fail with Out Of Gas error if the code has a length more than max_initcode_size.

  
    
      
      
         Rationale
      
      
    


TBA

  
    
      
      
         Backwards Compatibility
      
      
    


This EIP requires a “network upgrade”, since it modifies consenus-rules.

  
    
      
      
         Security Considerations
      
      
    


For client implementations, this EIP makes attacks based on jumpdest-analysis or hashing of code less problematic, so should increase the robustness of clients.


For layer 2, this EIP introduces failure-modes where there previously were none. There could exist factory-contracts which deploy multi-level contract hierarchies, such that the code for multiple contracts are included in the initcode of the first contract. The author(s) of this EIP are not aware of any such contracts.

  
    
      
      
         Test Cases
      
      
    


Test cases should include the following cases,


	CREATE/CREATE2/tx create with initcode_size at max_initcode_size
	CREATE/CREATE2/tx create with initcode_size at max_initcode_size+1


  
    
      
      
         Implementation
      
      
    


TBA

  
    
      
      
         Copyright
      
      
    

Copyright and related rights waived via CC0.


  Citation

  Please cite this document as:

  
  Martin Holst Swende (@holiman), Paweł Bylica (@chfast), Alex Beregszaszi (@axic), "EIP-2677: Limit size of `initcode` [DRAFT]," Ethereum Improvement Proposals, no. 2677, May 2020. [Online serial]. Available: https://eips.ethereum.org/EIPS/eip-2677.






      
    
  

  

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        Ethereum Improvement Proposals (EIPs) describe standards for the Ethereum platform, including core protocol specifications, client APIs, and contract standards.