EIP-2970: IS_STATIC opcode


  Ethereum Improvement Proposals
        
        
          
            
              
            
          
        

        AllCoreNetworkingInterfaceERCMetaInformational

      



      
        
  
    

  
    
      🚧 Stagnant
    
    
    
    
    
      Standards Track: Core
    
  
  
    
      EIP-2970: IS_STATIC opcode
    
    
      
        
      
    
    
      
        
      
    
  

  

  	Authors	Vitalik Buterin (@vbuterin)
	Created	2020-09-13
	Discussion Link	https://ethereum-magicians.org/t/is-static-opcode-useful-for-aa/4609


  


  

  
    Table of Contents

    	Simple Summary
	Abstract
	Motivation
	Specification
	Rationale
	Backwards Compatibility
	Security Considerations
	Copyright



  


  
      
      
         Simple Summary
      
      
    


Add a IS_STATIC (0x4A) opcode that pushes 1 if the current context is static (ie. the execution is in a STATICCALL or a descendant thereof, so state-changing operations are not possible), and 0 if it is not.

  
    
      
      
         Abstract
      
      
    

  
    
      
      
         Motivation
      
      
    


The main intended use case is to allow account abstraction (EIP 2938) to be extended so that accounts can allow static calls from the outside (which are harmless to AA’s security model) but not state-changing calls.

  
    
      
      
         Specification
      
      
    


Add a IS_STATIC (0x4A) opcode that pushes 1 if the current context is static (ie. the execution is in a STATICCALL or a descendant thereof, so state-changing operations are not possible), and 0 if it is not.

  
    
      
      
         Rationale
      
      
    


Determining staticness is already possibly using the following hacky technique: make a CALL with limited gas, and inside that CALL issue one LOG and exit. If the context is static, the CALL would fail and leave a 0 on the stack; if the context is non-static, the CALL would succeed. However, this technique is fragile against changes to gas costs, and is needlessly wasteful. Hence, the status quo neither allows a reasonably effective way of determining whether or not the context is static, nor provides any kind of invariant that executions that do not fail outright will execute the same way in a static and non-static context. This EIP provides a cleaner way of determining staticness.

  
    
      
      
         Backwards Compatibility
      
      
    


TBD

  
    
      
      
         Security Considerations
      
      
    


TBD

  
    
      
      
         Copyright
      
      
    

Copyright and related rights waived via CC0.


  Citation

  Please cite this document as:

  
  Vitalik Buterin (@vbuterin), "EIP-2970: IS_STATIC opcode [DRAFT]," Ethereum Improvement Proposals, no. 2970, September 2020. [Online serial]. Available: https://eips.ethereum.org/EIPS/eip-2970.






      
    
  

  

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